Dan Twelker

Interests

Research

I am site Principal Investigator of the CHAMP Myopia Study, a clinical trail of 2 concentrations of dilute atropine versus placebo.

Teaching

I enjoy teaching clinical procedures such as retinoscopy and refraction. I fit contact lenses, both soft and rigid gas permeable.

Courses

No activities entered.

Scholarly Contributions

Journals/Publications

• Mutti, D. O., Sinnott, L. T., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Zadnik, K. (2025). Axial length as a function of age, sex, and ethnicity: Results from the CLEERE study. Optometry and vision science : official publication of the American Academy of Optometry, 102(Issue 11). doi:10.1097/opx.0000000000002304
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  SIGNIFICANCE: Axial length is emerging as the primary outcome variable used for assessing myopia control efficacy, in both clinic and clinical trials. This report provides a model of axial length as a function of age, sex, and race/ethnicity, in addition to percentiles of axial length across age in childhood. PURPOSE: To model axial length in juvenile-onset myopia and children in general as a function of age, sex, race/ethnicity, parental history of myopia, diopter-hours of near work, and hours of outdoor/sports activities. METHODS: Axial length from the time of myopia onset was modeled using quadratic fits as a function of age, sex, race/ethnicity, and other covariates. Myopic participants were 590 children in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) study with at least three annual visits: one without myopia, an onset visit 1 year later (spherical equivalent at least -0.75 D), and another visit after myopia onset. Percentiles for axial length from the entire CLEERE sample were determined using 23,154 observations from 4877 children. RESULTS: Axial elongation in myopic children was greatest at younger ages, slowing with age in a quadratic trajectory between 6 and 14 years. The average rate of elongation at a given age, however, was independent of the age of myopia onset. In the general sample of children, axial length percentiles at age 6 years were similar across racial/ethnic groups, but Asian American children had the steepest increases in axial length with age, followed by Native American and Hispanic children. The shallowest increases occurred in Black and White children. Females had shorter axial lengths than males by 0.4 to 0.5 mm, but a higher probability of being myopic for a given age and axial length percentile. Parental history of myopia, time spent reading, and time spent in outdoor/sports activity were not significant factors for axial length in multivariate models. CONCLUSIONS: The models of axial length as a function of age, sex, and race/ethnicity, along with their percentiles, may prove useful in sample size planning for clinical trials, for judging efficacy of myopia control in individual children, and for comparison to more recent datasets.
• Mutti, D. O., Sinnott, L. T., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., Zadnik, K., & , C. S. (2025). Axial length as a function of age, sex, and ethnicity: Results from the CLEERE study. Optometry and vision science : official publication of the American Academy of Optometry, 102(11), 681-690.
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  Axial length is emerging as the primary outcome variable used for assessing myopia control efficacy, in both clinic and clinical trials. This report provides a model of axial length as a function of age, sex, and race/ethnicity, in addition to percentiles of axial length across age in childhood.
• Sanchez, J., Gerhart, K., Arthur, A. W., Harvey, E., Twelker, J. D., Hsu, C. H., Dennis, L. K., & Miller, J. M. (2025). Vision and developmental delay in toddlers. Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus, 104650.
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  Research investigating an association between vision impairment and toddlers' ability to reach developmental milestones is sparse. Medical records of children 11-37 months of age who had automated vision screening were retrospectively reviewed to evaluate whether such an association was present. A lower likelihood of development delay was associated with female sex and Hispanic patients. However, developmental delay diagnosis was not associated with failing automated vision screening.
• Sanchez, J., Gerhart, K., Arthur, A. W., Harvey, E., Twelker, J. D., Hsu, C. H., Dennis, L. K., & Miller, J. M. (2025). Vision and developmental delay in toddlers. Journal of AAPOS, 29(Issue 5). doi:10.1016/j.jaapos.2025.104650
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  Research investigating an association between vision impairment and toddlers’ ability to reach developmental milestones is sparse. Medical records of children 11-37 months of age who had automated vision screening were retrospectively reviewed to evaluate whether such an association was present. A lower likelihood of development delay was associated with female sex and Hispanic patients. However, developmental delay diagnosis was not associated with failing automated vision screening.
• Twelker, J. D., Arthur, A. W., Bhakta, R., Davis, A. L., Dennis, L. K., Enriquez, S. G., Gerhart, K. D., Hsu, C. H., González Marshall, M. S., Martin, J., McGrath, E. R., Miller, J. M., Ramesh, D., & Harvey, E. M. (2025). Agreement between the Spot Vision Screener and cycloplegic retinoscopy for toddlers with astigmatism. Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus, 104656.
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  We investigated the agreement between the Spot Vision Screener (Welch Allyn) and gold standard cycloplegic retinoscopy in infants and toddlers, with special attention to astigmatism.
• Twelker, J. D., Arthur, A. W., Bhakta, R., Davis, A. L., Dennis, L. K., Enriquez, S. G., Gerhart, K. D., Hsu, C. H., González Marshall, M. S., Martin, J., McGrath, E. R., Miller, J. M., Ramesh, D., & Harvey, E. M. (2025). Agreement between the Spot Vision Screener and cycloplegic retinoscopy for toddlers with astigmatism. Journal of AAPOS, 29(Issue 5). doi:10.1016/j.jaapos.2025.104656
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  Background: We investigated the agreement between the Spot Vision Screener (Welch Allyn) and gold standard cycloplegic retinoscopy in infants and toddlers, with special attention to astigmatism. Methods: Participants were children 12-35 months of age who failed a routine photoscreening using the Spot conducted at a recent well-child visit and who subsequently received a cycloplegic eye examination through the Spectacle Prescribing in Early Childhood Study (SPECS). Results: The final sample included 410 children, with an average age of 20.24 months. The Spot mean spherical equivalent value (M) was significantly less hyperopic than cycloplegic retinoscopy M (+0.35 D vs +0.80 D, t[409] < 0.001), and mean Spot Vision Screener cylinder (CYL) was significantly higher than cycloplegic retinoscopy CYL (1.84 D. vs 1.58 D, t[409] < 0.001). Conclusions: Cycloplegic retinoscopy found more hyperopic, or conversely, less myopic sphere power, in 60% of participants at the clinically significant level of >0.50 D. When using the Spot, this could result in under-referral to an eye care professional for moderate to high hyperopia. About 1 in 4 subjects showed higher clinically significant cylinder (>1.00 D) using the Spot compared with cycloplegic retinoscopy, which could result in over-referral for astigmatism when using the 2013 criteria for astigmatism.
• Mutti, D. O., Sinnott, L. T., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Zadnik, K. (2024). Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study. Optometry and Vision Science, 101(Issue 4). doi:10.1097/opx.0000000000002127
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  SIGNIFICANCE Clinicians and researchers would benefit from being able to predict the onset of myopia for an individual child. This report provides a model for calculating the probability of myopia onset, year-by-year and cumulatively, based on results from the largest, most ethnically diverse study of myopia onset in the United States. PURPOSE This study aimed to model the probability of the onset of myopia in previously nonmyopic school-aged children. METHODS Children aged 6 years to less than 14 years of age at baseline participating in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study who were nonmyopic and less hyperopic than +3.00 D (spherical equivalent) were followed up for 1 to 7 years through eighth grade. Annual measurements included cycloplegic autorefraction, keratometry, ultrasound axial dimensions, and parental report of children's near work and time spent in outdoor and/or sports activities. The onset of myopia was defined as the first visit with at least -0.75 D of myopia in each principal meridian. The predictive model was built using discrete time survival analysis and evaluated with C statistics. RESULTS The model of the probability of the onset of myopia included cycloplegic spherical equivalent refractive error, the horizontal/vertical component of astigmatism (J0), age, sex, and race/ethnicity. Onset of myopia was more likely with lower amounts of hyperopia and less positive/more negative values of J0. Younger Asian American females had the highest eventual probability of onset, whereas older White males had the lowest. Model performance increased with older baseline age, with C statistics ranging from 0.83 at 6 years of age to 0.92 at 13 years. CONCLUSIONS The probability of the onset of myopia can be estimated for children in the major racial/ethnic groups within the United States on a year-by-year and cumulative basis up to age 14 years based on a simple set of refractive error and demographic variables.
• Mutti, D. O., Sinnott, L. T., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Zadnik, K. (2024). Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study. Optometry and vision science : official publication of the American Academy of Optometry, 101(4), 179-186.
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  Clinicians and researchers would benefit from being able to predict the onset of myopia for an individual child. This report provides a model for calculating the probability of myopia onset, year-by-year and cumulatively, based on results from the largest, most ethnically diverse study of myopia onset in the United States.
• Zadnik, K., Schulman, E., Flitcroft, I., Fogt, J. S., Blumenfeld, L. C., Fong, T. M., Lang, E., Hemmati, H. D., Chandler, S. P., & , C. T. (2023). Efficacy and Safety of 0.01% and 0.02% Atropine for the Treatment of Pediatric Myopia Progression Over 3 Years: A Randomized Clinical Trial. JAMA ophthalmology, 141(10), 990-999.
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  The global prevalence of myopia is predicted to approach 50% by 2050, increasing the risk of visual impairment later in life. No pharmacologic therapy is approved for treating childhood myopia progression.
• Mutti, D. O., Sinnott, L. T., Brennan, N. A., Cheng, X., Zadnik, K., & , C. L. (2022). The Limited Value of Prior Change in Predicting Future Progression of Juvenile-onset Myopia. Optometry and vision science : official publication of the American Academy of Optometry, 99(5), 424-433.
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  Identifying children at highest risk for rapid myopia progression and/or rapid axial elongation could help prioritize who should receive clinical treatment or be enrolled in randomized clinical trials. Our models suggest that these goals are difficult to accomplish.
• Jones-Jordan, L. A., Sinnott, L. T., Chu, R. H., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Mutti, D. O., Twelker, J. D., Zadnik, K., & , C. S. (2021). Myopia Progression as a Function of Sex, Age, and Ethnicity. Investigative ophthalmology & visual science, 62(10), 36.
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  To model juvenile-onset myopia progression as a function of race/ethnicity, age, sex, parental history of myopia, and time spent reading or in outdoor/sports activity.
• Kleinstein, R. N., Mutti, D. O., Sinnott, L. T., Jones-Jordan, L. A., Cotter, S. A., Manny, R. E., Twelker, J. D., & Zadnik, K. (2021). Uncorrected Refractive Error and Distance Visual Acuity in Children Aged 6 to 14 Years. Optometry and Vision Science, 98(1), 3-12. doi:10.1097/opx.0000000000001630
• Kleinstein, R. N., Mutti, D. O., Sinnott, L. T., Jones-Jordan, L. A., Cotter, S. A., Manny, R. E., Twelker, J. D., Zadnik, K., & , C. L. (2021). Uncorrected Refractive Error and Distance Visual Acuity in Children Aged 6 to 14 Years. Optometry and vision science : official publication of the American Academy of Optometry, 98(1), 3-12.
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  This study presents the relationship between distance visual acuity and a range of uncorrected refractive errors, a complex association that is fundamental to clinical eye care and the identification of children needing refractive correction.
• Walline, J. J., Lindsley, K. B., Vedula, S. S., Cotter, S. A., Mutti, D. O., Ng, S. M., & Twelker, J. D. (2020). Interventions to slow progression of myopia in children. The Cochrane database of systematic reviews, 1, CD004916.
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  Nearsightedness (myopia) causes blurry vision when one is looking at distant objects. Interventions to slow the progression of myopia in children include multifocal spectacles, contact lenses, and pharmaceutical agents.
• Dennis, L. K., Twelker, J. D., Miller, J. M., Davis, A. L., Romer McGrath, E. F., & Harvey, E. M. (2018). A Preliminary Study of Astigmatism and Early Childhood Development. Journal of AAPOS.
• Dennis, L. K., Twelker, J. D., Miller, J. M., McGrath, E. R., & Harvey, E. M. (2018). A Preliminary Study of Astigmatism and Early Childhood Development. Journal of American Association of Pediatric Ophthalmology and Strabismus.
• Harvey, E. M., McGrath, E. R., Miller, J. M., Davis, A. L., Twelker, J. D., & Dennis, L. K. (2018). A preliminary study of astigmatism and early childhood development. Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus, 22(4), 294-298.
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  To determine whether uncorrected astigmatism in toddlers is associated with poorer performance on the Bayley Scales of Infant and Toddler Development, 3rd edition (BSITD-III).
• Harvey, E. M., Miller, J. M., Davis, A. L., Twelker, J. D., & Dennis, L. K. (2018). Spectacle Wear in Toddlers: Frequency of Wear and Impact of Treatment on the Child and Family. Translational vision science & technology, 7(6), 43.
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  We assessed the frequency of spectacle wear and impact of spectacle treatment in toddlers.
• Harvey, E. M., Leonard-Green, T. K., Mohan, K. M., Kulp, M. T., Davis, A. L., Miller, J. M., Twelker, J. D., Campus, I., & Dennis, L. K. (2017). Interrater and Test-Retest Reliability of the Beery Visual-Motor Integration in Schoolchildren. Optometry and vision science : official publication of the American Academy of Optometry, 94(5), 598-605.
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  To assess interrater and test-retest reliability of the 6th Edition Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and test-retest reliability of the VMI Visual Perception Supplemental Test (VMIp) in school-age children.
• Harvey, E. M., Leonard-Green, T. K., Mohan, K., Kulp, M. T., Davis, A. L., Miller, J. M., Twelker, J. D., Campus, I., & Dennis, L. K. (2017). Interrater and Test-Retest Reliability of the Beery Visual-Motor Integration in Schoolchildren. Optometry and Vision Science, 94(5), 598-605.
• Harvey, E. M., Twelker, J. D., Miller, J. M., Leonard-Green, T. K., Mohan, K. M., Davis, A. L., & Campus, I. (2017). Visual Motor and Perceptual Task Performance in Astigmatic Students. Journal of ophthalmology, 2017, 6460281.
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  . To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. . Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D) or bilateral astigmatism group (right and left eye ≥ 1.00 D) based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI) and Visual Perception (VMIp). Astigmats were randomly assigned to testing with/without correction and control group was tested uncorrected. Analyses compared VMI and VMIp scores for corrected and uncorrected astigmats to the control group. . The sample included 333 students (control group 170, astigmats tested with correction 75, and astigmats tested uncorrected 88). Mean VMI score in corrected astigmats did not differ from the control group ( = 0.829). Uncorrected astigmats had lower VMI scores than the control group ( = 0.038) and corrected astigmats ( = 0.007). Mean VMIp scores for uncorrected ( = 0.209) and corrected astigmats ( = 0.124) did not differ from the control group. Uncorrected astigmats had lower mean scores than the corrected astigmats ( = 0.003). . Uncorrected astigmatism influences visual motor and perceptual task performance. Previously spectacle treated astigmats do not show developmental deficits on visual motor or perceptual tasks when tested with correction.
• Mutti, D. O., Mitchell, G. L., Jones-Jordan, L. A., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., Zadnik, K., & , C. S. (2017). The Response AC/A Ratio Before and After the Onset of Myopia. Investigative ophthalmology & visual science, 58(3), 1594-1602.
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  To investigate the ratio of accommodative convergence per diopter of accommodative response (AC/A ratio) before, during, and after myopia onset.
• Davis, A. L., Harvey, E. M., Twelker, J. D., Miller, J. M., Leonard-Green, T., & Campus, I. (2016). Convergence Insufficiency, Accommodative Insufficiency, Visual Symptoms, and Astigmatism in Tohono O'odham Students. Journal of ophthalmology, 2016, 6963976.
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  Purpose. To determine rate of convergence insufficiency (CI) and accommodative insufficiency (AI) and assess the relation between CI, AI, visual symptoms, and astigmatism in school-age children. Methods. 3rd-8th-grade students completed the Convergence Insufficiency Symptom Survey (CISS) and binocular vision testing with correction if prescribed. Students were categorized by astigmatism magnitude (no/low:
• Harvey, E. M., Miller, J. M., Twelker, J. D., & Davis, A. L. (2016). Reading Fluency in School-Aged Children with Bilateral Astigmatism. Optometry and vision science : official publication of the American Academy of Optometry, 93(2), 118-25.
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  To compare oral reading fluency (ORF) in students with no/low astigmatism and moderate/high astigmatism and to assess the impact of spectacle correction on ORF in moderate and high astigmats.
• Twelker, J. D., Leonard-Green, T. K., Davis, A. L., Crescioni, M., Campus, I., Mohan, K., Miller, J. M., & Harvey, E. M. (2016). Convergence Insufficiency, Accommodative Insufficiency, Visual Symptoms, and Astigmatism in Tohono O'odham Students.. Journal of Ophthalmology.
• Harvey, E. M., Miller, J. M., Twelker, J. D., & Sherrill, D. L. (2015). Longitudinal change and stability of refractive, keratometric, and internal astigmatism in childhood. Investigative ophthalmology & visual science, 56(1), 190-8.
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  To assess longitudinal change in refractive, keratometric, and internal astigmatism in a sample of students from a population with a high prevalence of with-the-rule (WTR) astigmatism and to determine the optical origins of changes in refractive astigmatism.
• Zadnik, K., Sinnott, L. T., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Mutti, D. O. (2015). Prediction of Juvenile-Onset Myopia. JAMA ophthalmology, 133(6), 683-9.
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  Myopia (nearsightedness) has its onset in childhood and affects about one-third of adults in the United States. Along with its high prevalence, myopia is expensive to correct and is associated with ocular diseases that include glaucoma and retinal detachment.
• Crescioni, M., Messer, D. H., Warholak, T. L., Miller, J. M., Twelker, J. D., & Harvey, E. M. (2014). Rasch analysis of the Student Refractive Error and Eyeglass Questionnaire. Optometry and vision science : official publication of the American Academy of Optometry, 91(6), 624-33.
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  To evaluate and refine a newly developed instrument, the Student Refractive Error and Eyeglasses Questionnaire (SREEQ), designed to measure the impact of uncorrected and corrected refractive error on vision-related quality of life (VRQoL) in school-aged children.
• Harvey, E. M., Miller, J. M., Apple, H. P., Parashar, P., Twelker, J. D., Crescioni, M., Davis, A. L., Leonard-Green, T. K., Campus, I., & Sherrill, D. L. (2014). Accommodation in astigmatic children during visual task performance. Investigative ophthalmology & visual science, 55(8), 5420-30.
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  To determine the accuracy and stability of accommodation in uncorrected children during visual task performance.
• Jones-Jordan, L. A., Sinnott, L. T., Graham, N. D., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Mutti, D. O., Twelker, J. D., & Zadnik, K. (2014). The contributions of near work and outdoor activity to the correlation between siblings in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study. Investigative ophthalmology & visual science, 55(10), 6333-9.
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  We determined the correlation between sibling refractive errors adjusted for shared and unique environmental factors using data from the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study.
• Twelker, J. D., Miller, J. M., Sherrill, D. L., & Harvey, E. M. (2013). Astigmatism and myopia in Tohono O'odham Native American children. Optometry and vision science : official publication of the American Academy of Optometry, 90(11), 1267-73.
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  To describe change in spherical equivalent (M) in a longitudinal sample of Tohono O'odham students ages 3 to 18 years and to test the hypothesis that astigmatism creates complex cues to emmetropization, resulting in increased change in M in the direction of increasing myopia and increased occurrence of myopia.
• Jones-Jordan, L. A., Sinnott, L. T., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Mutti, D. O., Twelker, J. D., & Zadnik, K. (2012). Time outdoors, visual activity, and myopia progression in juvenile-onset myopes. Investigative ophthalmology & visual science, 53(11), 7169-75.
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  To investigate the association between myopia progression and time spent outdoors and in various visual activities.
• Manny, R. E., Sinnott, L. T., Jones-Jordan, L. A., Messer, D., Twelker, J. D., Cotter, S. A., Kleinstein, R. N., & Crescioni, M. (2012). Predictors of adequate correction following vision screening failure. Optometry and vision science : official publication of the American Academy of Optometry, 89(6), 892-900.
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  To determine whether compliance with referral 1 year after vision screening failure was associated with care model, demographic, or ocular factors.
• Messer, D. H., Mitchell, G. L., Twelker, J. D., & Crescioni, M. (2012). Spectacle wear in children given spectacles through a school-based program. Optometry and vision science : official publication of the American Academy of Optometry, 89(1), 19-26.
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  To investigate factors associated with spectacle wear in a group of primarily Native-American children provided spectacles free of charge through a school-based vision program.
• Mutti, D. O., Mitchell, G. L., Sinnott, L. T., Jones-Jordan, L. A., Moeschberger, M. L., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Zadnik, K. (2012). Corneal and crystalline lens dimensions before and after myopia onset. Optometry and vision science : official publication of the American Academy of Optometry, 89(3), 251-62.
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  To describe corneal and crystalline lens dimensions before, during, and after myopia onset compared with age-matched emmetropic values.
• Jones-Jordan, L. A., Mitchell, G. L., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Mutti, D. O., Twelker, J. D., Sims, J. R., & Zadnik, K. (2011). Visual activity before and after the onset of juvenile myopia. Investigative ophthalmology & visual science, 52(3), 1841-50.
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  To investigate visual activities before and after the onset of juvenile myopia.
• Manny, R. E., Mitchell, G. L., Cotter, S. A., Jones-Jordan, L. A., Kleinstein, R. N., Mutti, D. O., Twelker, J. D., & Zadnik, K. (2011). Intraocular pressure, ethnicity, and refractive error. Optometry and vision science : official publication of the American Academy of Optometry, 88(12), 1445-53.
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  The ethnically diverse Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study cohort provides a unique opportunity to explore associations among intraocular pressure (IOP), ethnicity, and refractive error while adjusting for potential confounding variables.
• Mutti, D. O., Sinnott, L. T., Mitchell, G. L., Jones-Jordan, L. A., Moeschberger, M. L., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D., & Zadnik, K. (2011). Relative peripheral refractive error and the risk of onset and progression of myopia in children. Investigative ophthalmology & visual science, 52(1), 199-205.
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  To investigate whether relative peripheral hyperopia is a risk factor for either the onset of myopia in children or the rate of myopic progression.
• Walline, J. J., Lindsley, K., Vedula, S. S., Cotter, S. A., Mutti, D. O., & Twelker, J. D. (2011). Interventions to slow progression of myopia in children. The Cochrane database of systematic reviews, CD004916.
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  Nearsightedness (myopia) causes blurry vision when looking at distant objects. Highly nearsighted people are at greater risk of several vision-threatening problems such as retinal detachments, choroidal atrophy, cataracts and glaucoma. Interventions that have been explored to slow the progression of myopia include bifocal spectacles, cycloplegic drops, intraocular pressure-lowering drugs, muscarinic receptor antagonists and contact lenses. The purpose of this review was to systematically assess the effectiveness of strategies to control progression of myopia in children.
• Hargadon, D. D., Wood, J., Twelker, J. D., Harvey, E. M., & Dobson, V. (2010). Recognition acuity, grating acuity, contrast sensitivity, and visual fields in 6-year-old children. Archives of ophthalmology (Chicago, Ill. : 1960), 128(1), 70-4.
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  To measure monocular distance visual acuity (VA), grating VA, contrast sensitivity, and visual field extent in full-term, 6-year-old children.
• Zadnik, K., Manny, R. E., Yu, J. A., Mitchell, G. L., Cotter, S. A., Quiralte, J. C., Shipp, M. D., Friedman, N. E., Kleinstein, R. N., Walker, T. W., Jones, L. A., Moeschberger, M. L., Mutti, D. O., Hullett, S., Sims, J., Weeks, R., Williams, S., Calvin, L. A., Qualley, P., , Crossnoe, C. J., et al. (2003). Ocular component data in schoolchildren as a function of age and gender. Optometry and Vision Science, 80(Issue 3). doi:10.1097/00006324-200303000-00012
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  Purpose. To describe the refractive error and ocular components of a large group of school-aged children as a function of age and gender. Methods. In this report, we describe the refractive error and ocular components of 2583 school-aged children (49.3% girls, overall mean [±SD] age 10.0 ± 2.3). Measurement methods included cycloplegic autorefraction, autokeratometry, videophakometry, and A-scan ultrasonography. For statistical comparisons across gender and age, a critical point of α = 0.005 was used to assess significance because of the large sample size and the large number of comparisons made. Results. Of these 2583 children, 10.1% were myopic (-0.75 D or more myopia in both meridians), and 8.6% were hyperopic (+1.25 D or more hyperopia in both meridians). As would be expected, there was a significant effect of age on refractive error (spherical equivalent, p < 0.0001), toward less hyperopia/more myopia. There was no significant difference in the average refractive error between girls and boys (p = 0.0192). Girls had steeper corneas than boys (0.74 D steeper in the vertical meridian and 0.63 D steeper in the horizontal meridian, p < 0.0001). There were no significant differences in corneal power with age (p = 0.16). Both older age and male gender were significantly associated with deeper anterior chambers (p < 0.0001 for both). The crystalline lens showed significant thinning with age (p < 0.0001), however, there was no significant difference in the lens thickness between girls and boys (p = 0.66). Both Gullstrand lens power and calculated lens power showed significant effects of age and gender (p < 0.0001 for both). Girls, on average, had Gullstrand lens powers that were 0.28 D steeper and calculated lens powers that were 0.80 D more powerful than boys. Axial length also showed significant effects of age and gender (p < 0.0001 for both). Girls' eyes were, on average, 0.32 mm shorter than those of boys. Conclusions. These cross-sectional data show a general pattern of ocular growth, no change in corneal power, and crystalline lens thinning and flattening between the ages of 6 and 14 years. Girls tended to have steeper corneas, stronger crystalline lenses, and shorter eyes compared with boys.
• Twelker, J. D., Bailey, I. L., Mannis, M. J., & Satariano, W. A. (2000). Evaluating pterygium severity: A survey of corneal specialists. Cornea, 19(Issue 3). doi:10.1097/00003226-200005000-00007
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  Purpose. Accurate and reliable evaluation techniques are essential for clinical and epidemiologic studies. This survey of corneal specialists was designed to lay a foundation for the further development of methods for evaluating and staging pterygium. Methods. In a self-administered, mailed questionnaire, 213 corneal specialists rated the importance of nine symptoms, nine signs, and nine clinical tests for the severity of primary pterygium. Severity was defined as the present need for surgical intervention. Results. The most important factors for determining primary pterygium severity were the extent of encroachment onto the cornea, decreased visual acuity, restricted ocular motility, and increased rate of growth. Many patient symptoms were rated as moderately to highly important. The questionnaire was shown to have good response reliability by test-retest comparisons. Cronbach's α was 0.89, which indicates very good internal consistency reliability. Conclusion. The survey identifies the priorities of experts in determining the severity of pterygium. More precise and clearly defined evaluation methods will enhance future clinical and epidemiologic studies of pterygium. The ranked list of pterygium signs, symptoms, and tests can serve as a guide for developing pterygium evaluation methods in the future. There is a need for a method that accurately and precisely quantifies the distance of pterygium encroachment onto the cornea and the pterygium progression rate. Furthermore, there is a need for an assessment of patient symptoms.
• Moore, B., Lyons, S. A., Walline, J., Bartolone, A., Harris, M., Kattouf, V., Mutti, D., Sarita Soni, P., & Daniel Twelker, J. (1999). A clinical review of hyperopia in young children. Optometry, 70(Issue 4).
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  Background: Hyperopia is the most common refractive error of children. Children with mild (or even moderate) levels of hyperopia usually do not experience visual problems resulting from this hyperopia. However, children with moderate-to-high degrees of hyperopia are at significantly increased risk for the development of amblyopia and strabismus. It is this association with these visually threatening disorders that makes hyperopia in children an important public health problem. In addition, even lesser degrees of hyperopia may affect the child's ability to perform well in near-related tasks, such as reading. The effect hyperopia has on an individual child is dependent on a variety of factors, including the magnitude of hyperopia, the age of the individual, the status of the accommodative and convergence system, and the demands placed on the visual system. Early detection and treatment of hyperopia may help prevention of potential complications from adversely impacting the child's vision. Although much is known about childhood hyperopia and its effects on vision, there is also much that is not known. The natural history, ocular biometry, relationship to accommodative function, the indications for treatment, and the most effective treatment modalities are among the underlying issues and clinical considerations awaiting more complete understanding.
• Daniel Twelker, J., Kirschbaum, S., Zadnik, K., & Mutti, D. O. (1997). Comparison of corneal versus through-the-lid A-scan ultrasound biometry. Optometry and Vision Science, 74(Issue 10). doi:10.1097/00006324-199710000-00024
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  Background. Accurate ultrasonography data on axial ocular dimensions in infants and toddlers are essential for understanding ocular development. Conventional methods using corneal contact with topical anesthesia but without sedation are not feasible for most of these patients. We evaluate an alternative method which places the probe on the closed eyelid. Methods. We compared A-scan ultrasound biometry measurements taken with the probe directly on the cornea with those with the probe on the closed eyelid on the right eye of 35 young adult subjects. Results. There was no significant difference between methods for mean anterior chamber depth (corneal = 3.83 mm, lid = 3.87 mm, p = 0.13, paired t-test). The mean lens thickness (corneal = 3.63 mm, lid = 3.75 mm, p = 0.0001, paired t-test) and mean vitreous chamber depth (corneal = 17.50 mm, lid = 17.68 mm, p = 0.0440, paired t-test) were significantly different. Conclusion. Ultrasonography through the closed eyelid appears to be a viable method with acceptable validity compared with corneal ultrasound. Poorer agreement for lens thickness and vitreous chamber depth may be undesirable, but these data should be useful for planning future studies of infants and toddlers. Background. Accurate ultrasonography data on axial ocular dimensions in infants and toddlers are essential for understanding ocular development. Conventional methods using corneal contact with topical anesthesia but without sedation are not feasible for most of these patients. We evaluate an alternative method which places the probe on the closed eyelid. Methods. We compared A-scan ultrasound biometry measurements taken with the probe directly on the cornea with those with the probe on the closed eyelid on the right eye of 35 young adult subjects. Results. There was no significant difference between methods for mean anterior chamber depth (corneal = 3.83 mm, lid = 3.87 mm, p = 0.13, paired t-test). The mean lens thickness (corneal = 3.63 mm, lid = 3.75 mm, p = 0.0001, paired t-test) and mean vitreous chamber depth (corneal = 17.50 mm, lid = 17.68 mm, p = 0.0440, paired t-test) were significantly different. Conclusion. Ultrasonography through the closed eyelid appears to be a viable method with acceptable validity compared with corneal ultrasound. Poorer agreement for lens thickness and vitreous chamber depth may be undesirable, but these data should be useful for planning future studies of infants and toddlers.
• Bullimore, M. A., Adams, C. W., Fusaro, R. E., Bauman, M., Cotteral, R. M., Ng Sarver, J., Twelker, J. D., & Graham, A. D. (1996). Acceptance of auto-refractor and clinician prescriptions: A randomized clinical trial. Investigative Ophthalmology and Visual Science, 37(Issue 3).
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  Purpose. We compared patient acceptance of spectacle prescriptions from an autorefractor with those obtained from a clinician in a randomized clinical trial. Methods. Two hundred and three patients (17 to 57 years) were recruited from the campus community and attended for examination by one of four clinicians. Contact lens wearers, optometry students, patients with acuities worse than 20/30 in either eye, and individuals with systemic diseases affecting refractive error were excluded. Seven patients were deemed by the clinician not to need a spectacle prescription after the exam and were excluded from the study. Additionally, two patients were lost to follow-up. Five auto-refractor readings were taken per eye, and later averaged, prior to a comprehensive exam by a study clinician. The two spectacle prescriptions were made up in a frame of the patient's choice. Patients wore the two spectacle prescriptions in double-masked, randomized, cross-over design, each for at least three weeks. Following each wearing period, subjects completed a short questionnaire regarding wearing schedule, adaptation and satisfaction. At the end of their participation, they were asked to select and retain their preferred prescription. Results. In response to the question "If you had purchased these spectacles for $100, would you be happy with them?", 115 patients considered both pairs acceptable, 42 accepted the clinician prescription only, 20 accepted the auto-refractor prescription only, and the remaining 17 rejected both pairs (p < 0.05). When asked which prescription they would like to keep, 99 patients preferred the clinician prescription, 54 preferred the auto-refractor prescription, and the remainder considered both equally acceptable. Patients rated the quality of vision significant higher for the clinician prescription and less difficulty with adaptation (p < 0.05). There was no significant difference for visual acuity nor wearing time. Conclusions. Overall, patient acceptance and satisfaction was lower for autorefractor prescriptions than for the clinician prescriptions.
• Twelker, J. D., Kirschbaum, S. K., Zadnik, K., & Mutti, D. O. (1996). Meridional development of the infant crystalline lens. Investigative Ophthalmology and Visual Science, 37(Issue 3).
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  Purpose. We previously presented biometric data from infants 4 to 15 months of age (ARVO, 1994). We are continuing our investigation of ocular growth and refractive development by examining two meridians of the crystalline lens in older infants. Methods. We evaluated the right eye of 11 subjects ranging from 9 to 29 months under cycloplegia (cyclopentolate 1% after proparacaine 0.5%). We assessed refractive error by retinoscopy, axial dimensions by A-scan ultrasonography, and corneal radius, crystalline lens radius, and crystalline lens power using a video-based keratophakometer which records Purkinje images I, III, and IV in two orthogonal meridians. Results. In the horizontal meridian, the mean anterior crystalline lens radius was 9.10 ± 0.79mm and the mean posterior radius was 4.79 ± 0.37mm. In the vertical meridian, the mean anterior crystalline lens radius was 9.35 ± 0.88mm and the mean posterior radius was 5.03 ± 0.38mm. The posterior crystalline lens radius in the horizontal meridian flattened with age (radius=3.98+0.05(age (months)), r=0.73, p=0.03) while the anterior crystalline lens radius was not quite statistically significant for age-related flattening (radius=7.57+0.09(age (months)), r=0.64, p=0.06). There were no statistically significant age-related trends in the anterior and posterior crystalline lens radius in the vertical meridian (anterior: r=0.52, p=0.10; posterior: r=0.16, p=0.64). Conclusions. In contrast to previous pilot data in infants from 4 to 15 months, which showed no age-related changes in crystalline lens radius, our data from older infants and toddlers show flatter crystalline lens radii in the horizontal posterior meridian with increasing age. The flattening of the horizontal posterior crystalline lens radius, while the other crystalline lens radii stayed the same, may contribute to a shift toward with-the-rule astigmatism. These cross-sectional trends require confirmation by longitudinal studies.
• Mutti, D. O., Zadnik, K., Egashira, S., Kish, L., Twelker, J. D., & Adams, A. J. (1994). The effect of cycloplegia on measurement of the ocular components. Investigative Ophthalmology and Visual Science, 35(Issue 2).
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  Purpose. The purpose of this study was to examine the effect of cycloplegic agent on the measurement of refractive error and the ocular components. Methods. We compared two commonly used topical cycloplegic agents, 1% tropicamide and 1% cyclopentolate, for their effect on the measurement of refractive error (by Canon R-1 autorefraction), accommodative response (by Canon R-1 autorefraction and by the conventional, subjective 'pushup' method), crystalline lens power (by video phakometry and by calculation), and axial ocular dimensions (by A-scan ultrasonography) in 20 emmetropic to moderately hyperopic children. Results. Comparison of refractive error at each drug's reported time of maximum cycloplegia (30 minutes for tropicamide and 60 minutes for cyclopentolate) showed that distance autorefraction in the vertical meridian differed by +0.20 ± 0.30 diopters (D) (P = 0.008). The average difference was +0.07 ± 0.10 mm for anterior chamber depth (P = 0.004), -0.03 ± 0.05 mm for crystalline lens thickness (P = 0.025), -0.65 ± 0.69 D for phakometrically measured crystalline lens power (P < 0.001), +0.03 ± 1.55 D for calculated crystalline lens power (P = 0.94), and -0.09 ± 0.19 mm for vitreous chamber depth (P = 0.062, all paired t tests; positive signs denote greater values with cyclopentolate). Residual accommodation was 0.47 and 0.67 D greater with tropicamide when measured by autorefraction and the pushup method (P = 0.013 and 0.08 respectively, paired t test). All significant differences were consistently in the direction of poorer cycloplegia with tropicamide. Conclusions. Although tropicamide, as expected, showed poorer cycloplegia compared to cyclopentolate, the degree of difference appeared to be small, with minimal effect on the measurement of distance refractive error and the ocular optical components.
• Egashira, S. M., Kish, L. L., Twelker, J. D., Mutti, D. O., Zadnik, K., & Adams, A. J. (1993). Comparison of cyclopentolate versus tropicamide cycloplegia in children. Optometry and Vision Science, 70(Issue 12). doi:10.1097/00006324-199312000-00005
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  This double masked study compares the cycloplegic effects of tropicamide 1% and cyclopentolate 1% in 20 nonstrabismic, nonamblyopic, hyperopic 6- to 12-year old children with a mean refractive error=+1.48 ± 1.10 diopters (D). Unlike previous studies which used only amplitude of accommodation to measure the depth of cycloplegia, this study compares refractive error as determined by retinoscopy, distance subjective refraction, and distance autorefraction (Canon R-1). In addition, we compare the amplitude of accommodation as measured by subjective push-up and objective autorefraction methods. There is no statistically significant difference between cyclopentolate and tropicamide for either cycloplegic retinoscopy or distance subjective refraction. Autorefraction measurement of refractive error shows a statistically significant but clinically unimportant bias (0.14 ± 0.30 D) toward more hyperopia with cyclopentolate. Both drops reveal latent hyperopia, and the mean latencies are not statistically different between the two cycloplegic agents. Latent hyperopia is not systematically related to the degree of hyperopia after tropicamide, but this relation is significant after cyclopentolate. No differences were found between refractive results with either agent at 30 min compared to 60 min after drop instillation. When measured objectively with the autorefractor, accommodation is inhibited more effectively by cyclopentolate than by tropicamide. Our results suggest that although tropicamide is not as effective as cyclopentolate in inhibiting accommodation it is, nevertheless, a useful cycloplegic agent for measuring distance refractive error of low to moderate hyperopia in school-aged children. © 1993 American Academy of Optometry.
• Johnson, C. A., Adams, A. J., Twelker, J. D., & Quigg, J. M. (1988). Age-related changes in the central visual field for short-wavelength-sensitive pathways. Journal of the Optical Society of America A: Optics and Image Science, and Vision, 5(Issue 12). doi:10.1364/josaa.5.002131
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  The sensitivity of short-wavelength-sensitive (SWS) cone pathways throughout the central 30-deg visual field was determined in both eyes of 62 normal volunteers between the ages of 20 and 72 years. We found an average SWS cone pathway sensitivity decrease with age of ˜0.15 log unit per decade. The sensitivity reduction was approximately linear, with a slightly larger decrease beyond the age of 50 years. The age-related SWS cone pathway sensitivity reductions also became larger as a function of increasing stimulus eccentricity. Measurements of ocular-media absorption characteristics in each eye revealed that 30-40% of the age-related sensitivity loss could be attributed to reductions in transmission of short-wavelength light by the ocular media. After corrections for preretinal media transmission loss, the decrease in the sensitivity of SWS cone pathways with age was ˜0.09 log unit per decade. This age-related loss is greater than age-related sensitivity decreases in the middle-wavelength-sensitive and/or long-wavelength-sensitive cones (appoximately 0.06 to 0.07 log unit per decade). In the age group older than 60 years, there was an inverse relationship between media-corrected SWS cone pathway sensitivity and media absorption characteristics (i.e., media-corrected SWS cone pathway sensitivity was higher in eyes with lower media transmission of short wavelengths). This relationship was not so evident for younger subjects. A similar inverse relationship between transmission loss in the ocular media and SWS cone pathway sensitivity was found between left and right eyes of the same individual. These findings raise the possibility that reductions in short-wavelength transmission by the ocular media may have a long-term protective effect against light-induced damage to SWS cone pathways. © 1988 Optical Society of America.

Presentations

• Miller, J. M., Ober, C., Leonard-Green, T., Twelker, J. D., Kramer, T. R., Miller, H., Mercer, D., & Harvey, E. M. (2013, Jun). Comparison of Objective Measures of Visual Acuity for Assessing Potential Change in Vision Following Cord Blood Transplant in Preverbal Children. Annual Meeting of the International Cord Blood Symposium. San Francisco, CA: Cord Blood Association.

Poster Presentations

• Twelker, J. D., Harvey, E. M., Arthur, A. W., Dennis, L. K., Davis, A. L., Enriquez, S., Gerhart, K., Hsu, C., Marshall-Gonzales, M. S., Martin, J. A., Romer McGrath, E. F., Miller, J. M., & Divya, R. (2023, April). Agreement between the Welch Allyn Spot Vision Screener and Cycloplegic Retinoscopy in Toddlers.. ARVO. New Orleans, LA: ARVO.
• Twelker, J. D., Harvey, E. M., Arthur, A. W., Dennis, L. K., Davis, A. L., Enriquez, S., Gerhart, K., Hsu, C., Marshall-Gonzales, M. S., Martin, J. A., Romer McGrath, E. F., Miller, J. M., & Divya, R. (2023, April). Agreement between the Welch Allyn Spot Vision Screener and Cycloplegic Retinoscopy in Toddlers.. Association for Research in Vision and Ophthalmology Annual Meeting. New Orleans, LA: ARVO.
• Campus, I., Leonard-Green, T., Davis, A., Twelker, J. D., Apple, H., Miller, J. M., & Harvey, E. M. (2017, May). Perception of Global Form and Motion in Students with Bilateral Astigmatism. Association for Research in Vision and Ophthalmology Annual Meeting.
• Harvey, E. M., Harvey, E. M., Harvey, E. M., Leonard-Green, T. K., Leonard-Green, T. K., Leonard-Green, T. K., Mohan, K., Mohan, K., Mohan, K., Kulp, M. T., Kulp, M. T., Kulp, M. T., Davis, A. L., Davis, A. L., Davis, A. L., Miller, J. M., Miller, J. M., Miller, J. M., Twelker, J. D., , Twelker, J. D., et al. (2016, May). Inter-Scorer and Test-Retest Reliability of the Beery-Buktenica Developmental Test of Visual-Motor Integration in School-Age Children. Association for Research in Vision and Ophthalmology Annual Meeting. Seattle, WA.
• Crescioni, M., Crescioni, M., Warholak, T. L., Warholak, T. L., Harvey, E. M., Harvey, E. M., Leonard Green, T., Green, T. K., Campus, I., Campus, I., Twelker, J. D., Twelker, J. D., Miller, J. M., & Miller, J. M. (2015, May). Validation of Self-Reported Spectacle Compliance Among School Aged Children and Parents Using Rasch Analysis. Annual Meeting of Association for Research in Vision and Ophthalmology. Denver, CO: Association for Research in Vision and Ophthalmology.
• Davis, A., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2015, May). The Relation Between Convergence Insufficiency and Astigmatism. Annual Meeting of the Association for Research in Vision and Ophthalmology. Denver, CO: Association for Research in Vision and Ophthalmology.
• Crescioni, M., Warholak, T. L., Twelker, J. D., Miller, J. M., Davis, A. L., & Harvey, E. M. (2014, May). Rasch Analysis of the Convergence Insufficiency Symptoms Survey (CISS) Used to Assess Symptom Reduction with Spectacle Correction Among Students. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Davis, A. L., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2014, May). Inter-Observer and Intra-Observer Reliability of Measurements of the Obliquity of Palpebral Fissures. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Green, T. K., Davis, A., Crescioni, M., Campus, I., Mohan, K., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2015, May). Comparison of Best-Corrected vs. Uncorrected Performance on the Beery VMI Developmental Test of Visual Perception in Astigmatic Children. Annual Meeting of Association for Research in Vision and Ophthalmology. Denver, CO: Association for Research in Vision and Ophthalmology.
• Harvey, E. M., Miller, J. M., Apple, H. P., Parasha, P., Apple, D., Twelker, J. D., Crescioni, M., Leonard-Green, T. K., & Davis, A. L. (2014, May). Accommodation Patterns in Astigmatic Children During Visual Task Performance. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Leonard-Green, T. K., Apple, H. P., Apple, D., Crescioni, M., Miller, J. M., Twelker, J. D., Davis, A. L., Campus, I., & Harvey, E. M. (2014, May). Meridional Amblyopia in Astigmatic Students Documented with Computer Generated Stimuli on Commercial Displays. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Miller, J. M., Harvey, E. M., Twelker, J. D., Belin, M. W., & Sherrill, D. L. (2014, May). Posterior Corneal Curvature Conforms to Anterior Cornea Curvature in Astigmatic Tohono O’odham Native American Schoolchildren. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Twelker, J. D., Miller, J. M., & Harvey, E. M. (2014, May). Native American Schoolchildren Tend to Emmetropize to the Spherical Equivalent, Regardless of Level of Astigmatism. Annual Meeting of Association for Research in Vision and Ophthalmology. Orlando, FL: Association for Research in Vision and Ophthalmology.
• Campus, I., Crescioni, M., Green, T. K., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2013, May). Effects of Eyeglass Correction on Oral Reading Fluency in Elementary and Middle School Children. Annual Meeting of Association for Research in Vision and Ophthalmology. Seattle, WA: Association for Research in Vision and Ophthalmology.
• Crescioni, M., Twelker, J. D., Miller, J. M., Green, T. K., Campus, I., & Harvey, E. M. (2013, May). Relation Between Grade and Gender and Reasons for Spectacle Non-Compliance Among School Aged Children. Annual Meeting of Association for Research in Vision and Ophthalmology. Seattle, WA: Association for Research in Vision and Ophthalmology.
• Harvey, E. M., Twelker, J. D., & Miller, J. M. (2013, May). Relation Between Refractive Astigmatism and Change in Spherical Equivalent with Age in a Sample of Native American Children Age 3 to 18 Years of Age. Annual Meeting of Association for Research in Vision and Ophthalmology. Seattle, WA: Association for Research in Vision and Ophthalmology.
• Twelker, J. D., Miller, J. M., Messer, D. H., & Harvey, E. M. (2013, May). The Magnitude and Symmetry of Corneal and Refractive Astigmatism. Annual Meeting of Association for Research in Vision and Ophthalmology. Seattle, WA: Association for Research in Vision and Ophthalmology.
• Adams, I., Crescioni, M., Messer, D. H., Green, T. K., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2012, May). Test-Retest Agreement on the Student Refractive Error and Eyeglass Questionnaire (SREEQ). Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Crescioni, M., Messer, D. H., Harvey, E. M., Twelker, J. D., & Miller, J. M. (2012, May). Construct Validation of the Student Refractive Error and Eyeglass Questionnaire. Annual Meeting of the Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Green, T. K., Adams, I. A., Crescioni, M., Messer, D. H., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2012, May). Type of Refractive Error and Grade as Predictors of Spectacle Wear in 1st-12th Grade Students. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Harvey, E. M., Miller, J. M., Schwiegerling, J. T., Sherrill, D. L., Messer, D. H., & Twelker, J. D. (2012, May). Longitudinal Change in Corneal Astigmatism in Tohono O'odham Infants and Toddlers. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Miller, J. M., Schwiegerling, J. T., Harvey, E. M., Sherrill, D. L., Messer, D. H., & Twelker, J. D. (2012, May). Data Reduction Strategies for Aberration Measurements in Tohono O'odham Infants and Children. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Adams, I., Green, T. K., Messer, D. H., Twelker, J. D., Miller, J. M., & Harvey, E. M. (2011, May). Use of a Modified Version of the Pediatric Refractive Error Profile (PREP) to Identify Factors Associated with Eyeglass Wearing Compliance. Annual Meeting of the Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Apple, H., Miller, J. M., Harvey, E. M., Green, T. K., Messer, D. H., & Twelker, J. D. (2011, May). Accommodative Lag Changes in Uncorrected Astigmatic and Non-Astigmatic Students While Attempting to Read Small and Large Letters. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Green, T. K., Miller, J. M., Apple, H. P., Harvey, E. M., Messer, D. H., & Twelker, J. D. (2011, May). Evaluation of the Grand Seiko WAM and Apple Micro-Display for the Study of Accommodative Response to Near Stimuli. Annual Meeting of the Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Harvey, E. M., Miller, J. M., Belin, M. W., Messer, D. H., & Twelker, J. D. (2011, May). Agreement Between Retinomax K+ and Pentacam Measurements of Anterior Corneal Astigmatism. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.
• Miller, J. M., Seltzer, R. G., Sherrill, D. L., Harvey, E. M., Twelker, J. D., & Messer, D. H. (2011, May). Stability of Refractive Astigmatism in a Large Longitudinal Sample of Tohono O'odham Children. Annual Meeting of Association for Research in Vision and Ophthalmology. Ft. Lauderdale: Association for Research in Vision and Ophthalmology.
• Twelker, J. D., Robine, M., Mohler, J., De Castro, D. K., & Miller, J. M. (2011, May). Evaluating the Performance of a Lay Visual Health Worker in Rural Honduras. Annual Meeting of the Association for Research in Vision and Ophthalmology. Ft. Lauderdale, FL: Association for Research in Vision and Ophthalmology.