About

Karla Zadnik is Dean of the College of Optometry and Glenn A. Fry Professor of Optometry and Physiological Optics at The Ohio State University. She is an esteemed patient-oriented researcher in the field of optometry and vision science. Dean Zadnik served as the study chairman for the National Eye Institute-funded Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study for 20 years and chaired the first-ever National Eye Institute-funded multicenter study based in optometry, the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. She has held leadership roles as a past president of the American Academy of Optometry, the Association of Schools and Colleges of Optometry, and the National Board of Examiners in Optometry. Additionally, she served a four-year term on the National Advisory Eye Council for the National Eye Institute/National Institutes of Health. In recognition of her contributions, she received the Academy's Prentice Award in 2020.

Research topics

• Medicine
• Ophthalmology
• Optometry
• Political Science
• Internal medicine
• Anesthesia
• Gerontology
• Physics
• Optics
• Physical therapy
• Public administration
• Pediatrics
• Nursing
• Demography
• Management
• Family medicine

Selected publications

• Axial length as a function of age, sex, and ethnicity: Results from the CLEERE study

  Optometry and Vision Science · 2025-10-23 · 3 citations

  articleOpen access

  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.

  PublisherOA PDFDOI

• Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study

  Optometry and Vision Science · 2024-04-01 · 15 citations

  articleOpen accessSenior author

  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.

  PublisherOA PDFDOI

• Is Recommending 0.01% Atropine for Myopia Control Clinically Meaningful?—Reply

  JAMA Ophthalmology · 2024-02-15 · 3 citations

  article1st authorCorresponding

  Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Ophthalmology HomeNew OnlineCurrent IssueFor Authors Podcast Journals JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2024 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Ophthalmology journal

  PublisherDOI

• Talkin' 'bout my(opia) generation: The impact of <i>Optometry and Vision Science</i>

  Optometry and Vision Science · 2024-02-01 · 1 citations

  article1st authorCorresponding

  VIRTUAL ISSUE EDITORIAL: This editorial fronts the first virtual issue for Optometry & Vision Science. Virtual issues are a collection of papers from previously published issues of the journal that are brought together in a single, online publication. They highlight the important contribution the journal has made in supporting myopia research. All the papers referenced and previously published in Optometry & Vision Science will be made free access for 1-month. The collection can be accessed here: https://journals.lww.com/optvissci/pages/collectiondetails.aspx?TopicalCollectionId=16.

  PublisherDOI

• 2020 Charles F. Prentice Lecture: I Can See Clearly Now

  Optometry and Vision Science · 2023-01-01 · 1 citations

  articleOpen access1st authorCorresponding

  ABSTRACT: The Charles F. Prentice Medal, which was first given the year I was born, is the highest research honor bestowed by the American Academy of Optometry. I received the Prentice Medal in 2020 and gave my presentation at the 2020 American Academy of Optometry meeting, which was entirely virtual. As the first female optometrist to receive the Prentice Medal, I am honored to be given the opportunity to provide this summary of my presentation.Myopia treatment choices to slow the progression of juvenile-onset myopia, especially in the first year of treatment, range from spectacles to contact lenses to pharmaceuticals. The value of the work described here that aims to predict the onset of myopia in children based on measurements that could be made by the optometrist is about to become more relevant than ever. What if the age-specific cutpoints could be used to use a low-risk treatment that would actually prevent the development of myopia altogether?

  PublisherOA PDFDOI

• Efficacy and Safety of 0.01% and 0.02% Atropine for the Treatment of Pediatric Myopia Progression Over 3 Years

  JAMA Ophthalmology · 2023 · 116 citations

  1st authorCorresponding
  • Medicine
  • Anesthesia
  • Pediatrics

  Importance: 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. Objective: To assess the safety and efficacy of NVK002 (Vyluma), a novel, preservative-free, 0.01% and 0.02% low-dose atropine formulation for treating myopia progression. Design, Setting, and Participants: This was a double-masked, placebo-controlled, parallel-group, randomized phase 3 clinical trial conducted from November 20, 2017, through August 22, 2022, of placebo vs low-dose atropine, 0.01% and 0.02% (2:2:3 ratio). Participants were recruited from 26 clinical sites in North America and 5 countries in Europe. Enrolled participants were 3 to 16 years of age with -0.50 diopter (D) to -6.00 D spherical equivalent refractive error (SER) and no worse than -1.50 D astigmatism. Interventions: Once-daily placebo, low-dose atropine, 0.01%, or low-dose atropine, 0.02%, eye drops for 36 months. Main Outcomes and Measures: The primary, prespecified end point was the proportion of participants' eyes responding to 0.02% atropine vs placebo therapy (<0.50 D myopia progression at 36 months [responder analysis]). Secondary efficacy end points included responder analysis for atropine, 0.01%, and mean change from baseline in SER and axial length at month 36 in a modified intention-to-treat population (mITT; participants 6-10 years of age at baseline). Safety measurements for treated participants (3-16 years of age) were reported. Results: A total of 576 participants were randomly assigned to treatment groups. Of these, 573 participants (99.5%; mean [SD] age, 8.9 [2.0] years; 315 female [54.7%]) received trial treatment (3 participants who were randomized did not receive trial drug) and were included in the safety set. The 489 participants (84.9%) who were 6 to 10 years of age at randomization composed the mITT set. At month 36, compared with placebo, low-dose atropine, 0.02%, did not significantly increase the responder proportion (odds ratio [OR], 1.77; 95% CI, 0.50-6.26; P = .37) or slow mean SER progression (least squares mean [LSM] difference, 0.10 D; 95% CI, -0.02 D to 0.22 D; P = .10) but did slow mean axial elongation (LSM difference, -0.08 mm; 95% CI, -0.13 mm to -0.02 mm; P = .005); however, at month 36, compared with placebo, low-dose atropine, 0.01%, significantly increased the responder proportion (OR, 4.54; 95% CI, 1.15-17.97; P = .03), slowed mean SER progression (LSM difference, 0.24 D; 95% CI, 0.11 D-0.37 D; P < .001), and slowed axial elongation (LSM difference, -0.13 mm; 95% CI, -0.19 mm to -0.07 mm; P < .001). There were no serious ocular adverse events and few serious nonocular events; none was judged as associated with atropine. Conclusions and Relevance: This randomized clinical trial found that 0.02% atropine did not significantly increase the proportion of participants' eyes responding to therapy but suggested efficacy for 0.01% atropine across all 3 main end points compared with placebo. The efficacy and safety observed suggest that low-dose atropine may provide a treatment option for childhood myopia progression. Trial Registration: ClinicalTrials.gov Identifier: NCT03350620.

  PublisherOA PDFDOI

• Compensation for Vitreous Chamber Elongation in Infancy and Childhood

  Optometry and Vision Science · 2023-01-01 · 18 citations

  articleOpen access

  SIGNIFICANCE: The ratios of diopters of change in refractive error produced per millimeter of eye elongation (D/mm) are rarely those predicted from geometric optics because of changes in other ocular components. Quantifying this optical compensation in millimeters instead of ratios reveals some important principles about eye growth and refractive error. PURPOSE: The study purpose was to sort total vitreous chamber elongation into millimeters that either contributed (uncompensated) or did not contribute to change in refractive error (compensated). METHODS: Participants were infants in the Berkeley Infant Biometry Study (n = 271, ages 3 months to 6 years) or schoolchildren in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (n = 456 emmetropes and 522 myopes, ages 6 to 14 years). Refractive error was measured using cycloplegic retinoscopy in infants (cyclopentolate 1%) and cycloplegic autorefraction in schoolchildren (tropicamide 1% or combined with cyclopentolate 1%). Axial dimensions were assessed using A-scan ultrasonography. Uncompensated millimeters were estimated from ratios of change in refractive error per millimeter of elongation using Gullstrand eye models. Compensated millimeters were the difference between measured elongation and uncompensated millimeters. RESULTS: Compensated millimeters exceeded uncompensated millimeters in emmetropic children across ages, but uncompensated millimeters exceeded compensated millimeters in myopic children. Compensated millimeters were highest in infancy and decreased with age, reaching less than 0.10 mm per year by age 10 years in both myopic and emmetropic children. There were no statistically significant differences in compensated millimeters between myopic and emmetropic children between ages 8 and 14 years ( P values from .17 to .73). CONCLUSIONS: The ability of the ocular components, primarily crystalline lens, to compensate for vitreous elongation is independent of the higher demands of myopic eye growth. The limited compensation after age 10 years suggests the target for elongation in myopia control needed to arrest myopia progression may be that seen in emmetropes or less.

  PublisherOA PDFDOI

• Evaluation of Rinsing Options for Rigid Gas Permeable Contact Lenses

  Eye & Contact Lens Science & Clinical Practice · 2023-07-20 · 1 citations

  articleSenior author

  OBJECTIVES: This study assessed the efficacy of various saline solutions as alternative methods to rinsing rigid gas permeable (RGP) lenses with tap water. METHODS: The exiting fluid pressure of five commercially available saline solutions was measured using a venous pressure transducer system. Rigid gas permeable lenses were cleaned with one of two commercially available cleaners and then rinsed with one of five saline solutions or with tap water. High-resolution imaging was performed after each rinse, and light transmission through the lens surface was determined by measuring the mean pixel count within a 1 mm by 1 mm square. RESULTS: The mean pixels/mm 2 and the rinsing method were correlated (Spearman rank order correlation, P <0.0001), that is, high pixel counts represented more lens surface deposits and residue, and as fluid pressure of the rinsing methods increased, mean pixels/mm 2 decreased. CONCLUSIONS: Measured fluid pressure relates to lens surface opacity suggesting that some products leave less residue than others. In addition, tap water, with its high exiting fluid pressure, seems to be the most effective option for removal of RGP cleaners from the contact lens surface. Despite these findings, tap water rinse is not encouraged because of its potential to lead to corneal inflammation and infection; therefore, the development of alternative procedures and products is needed.

  PublisherDOI

• Myopia Progression as a Function of Sex, Age, and Ethnicity

  Investigative Ophthalmology & Visual Science · 2021 · 135 citations

  Senior authorCorresponding
  • Demography
  • Medicine
  • Ophthalmology

  Purpose: 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. Methods: Subjects were 594 children in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study with at least three study visits: one visit with a spherical equivalent (SPHEQ) less myopic/more hyperopic than -0.75 diopter (D), the first visit with a SPHEQ of -0.75 D or more myopia (onset visit), and another after myopia onset. Myopia progression from the time of onset was modeled using cubic models as a function of age, race/ethnicity, and other covariates. Results: Younger children had faster progression of myopia; for example, the model-estimated 3-year progression in an Asian American child was -1.93 D when onset was at age 7 years compared with -1.43 D when onset was at age 10 years. Annual progression for girls was 0.093 D faster than for boys. Asian American children experienced statistically significantly faster myopia progression compared with Hispanic (estimated 3-year difference of -0.46 D), Black children (-0.88 D), and Native American children (-0.48 D), but with similar progression compared with White children (-0.19 D). Parental history of myopia, time spent reading, and time spent in outdoor/sports activity were not statistically significant factors in multivariate models. Conclusions: Younger age, female sex, and racial/ethnic group were the factors associated with faster myopic progression. This multivariate model can facilitate the planning of clinical trials for myopia control interventions by informing the prediction of myopia progression rates.

  PublisherDOI

• Predicting the onset of myopia in children: results from the CLEERE study

  BMC Ophthalmology · 2021-07-14 · 12 citations

  articleOpen accessSenior author

  Research often attempts to identify risk factors associated with prevalent disease or that change the probability of developing disease. These factors may also help in predicting which individuals may go on to develop the condition of interest. However, risk factors may not always serve as the best predictive factors and not all predictive factors should be considered as risk factors. A child's current refractive error, parental history of myopia, and the amount of time children spend outdoors are excellent examples. Parental myopia and time outdoors are meaningful risk factors because they alter the probability of developing myopia and point to important hereditary and environmental influences. A child's current refractive error points to no particular mechanism and is therefore a poor risk factor. However, it serves as an excellent predictive factor for identifying children likely to develop future myopia. Risk factors may explain how a child reached a particular level of refractive error, but knowledge of that history may not be needed in order to make an accurate prediction about future refractive error. Current refractive error alone may be sufficient. This difference between risk factors and predictive factors is not always appreciated in the literature, including a recent publication in BMC Ophthalmology. This letter attempts to make that distinction and to explain why parental myopia and time outdoors are significant risk factors in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error, yet are not significant for predicting future myopia in a multivariate model that contains current refractive error.

  PublisherOA PDFDOI

Recent grants

• NIH Grant R21EY012273

  NIH · $526k · 2004

• NIH Grant U10EY008893

  NIH · $25.1M · 2013

• NIH Grant R24EY014792

  NIH · $1.0M · 2010

• NIH Grant U10EY010419

  NIH · $10.4M · 2007

• NIH Grant T32EY013359

  NIH · $1.1M · 2012

Frequent coauthors

• Donald O. Mutti

  264 shared

• G. Lynn Mitchell

  SUNY College of Optometry

  136 shared

• Joseph T. Barr

  The Ohio State University

  132 shared

• Timothy B. Edrington

  Marshall B. Ketchum University

  120 shared

• Mae O. Gordon

  88 shared

• Loraine T. Sinnott

  SUNY College of Optometry

  80 shared

• Mark A. Bullimore

  University of Houston

  68 shared

• Lisa Jones

  67 shared

Labs

• Karla Zadnik LabPI

Education

• Ph.D., Vision Science

  The Ohio State University

  2005

• M.S., Vision Science

  The Ohio State University

  2001

• B.S., Optometry

  The Ohio State University

  1998

Awards & honors

• Prentice Award (2020)