About

Rebecca A. Deffler, OD PhD, is an Assistant Professor at The Ohio State University College of Optometry. Her research interests include the delivery of low vision rehabilitation care and interactions among vision and driving. She teaches VS 6500 Geometric Optics in the first-year didactic curriculum and supervises fourth-year interns as a clinical attending in the Low Vision Rehabilitation Service. Dr. Deffler earned her BS from Gettysburg College in 2013, her OD from the New England College of Optometry in 2017, and her MS (2019) and PhD (2024) in Vision Science from The Ohio State University. Her MS was earned as part of an Advanced Practice Fellowship in Low Vision Rehabilitation, which included advanced clinical training at the College of Optometry. She is a Fellow of the American Academy of Optometry and was twice awarded Ezell Fellowships through the American Academy of Optometry Foundation.

Research topics

• Medicine
• Optometry
• Ophthalmology
• Computer science
• Audiology

Selected publications

• Bioptic driving: Historical milestones, current landscape, and future directions

  Optometry and Vision Science · 2026-03-01

  articleOpen access1st authorCorresponding

  A bioptic telescope is a small telescope mounted in the upper portion of a pair of eyeglasses that, when used for driving, allows a driver with central vision loss to briefly spot through the telescope to gain a magnified view of the roadway scene ahead. This paper summarizes the various ways bioptic driving has been studied, provides an update on bioptic driving research, and suggests future areas of work related to bioptic drivers. As the number of jurisdictions permitting bioptic driving increases, this review provides context regarding the history of bioptic driving, characteristics of bioptic drivers, and the safety of these drivers with vision impairment. Recent research has incorporated naturalistic recording methods that allow for study of specific safety events, the measurement of collision and near collision behavior on open roads, and adjustment for driving exposure in ways not previously possible. Still, studies of bioptic driving safety have been limited to North America, and small sample sizes and inadequate control groups remain challenges to interpretation, and more work should be done to determine what characteristics of bioptic drivers and other factors are related to safety. Suggestions for future research include study of the effects of newer advanced driver assistance systems on bioptic driving and development of evidence-based training programs.

  PublisherDOI

• Hard braking events in bioptic drivers with central vision impairment

  Ophthalmic and Physiological Optics · 2025-03-27 · 2 citations

  articleOpen access1st authorCorresponding

  PURPOSE: Some individuals with central vision impairment can obtain or maintain driving privileges using bioptic telescopes. Previous work has often demonstrated an increased collision risk for bioptic drivers, but some on-road studies find similar safety to that of normally sighted drivers. The purpose of this study was to compare exposure-controlled hard braking and speeding events measured with naturalistic recording in visually impaired bioptic drivers and normally sighted control drivers. METHODS: Visual acuity was measured for each eye individually and through the bioptic when indicated. Contrast sensitivity was measured binocularly with the Mars chart. Binocular integrated visual fields were constructed from monocular 24-2C SITA Faster plots. A commercially available GPS recorder was installed into drivers' personal vehicles for at least 6 weeks. Total mileage, instances of hard braking, travel over 65 miles per hour (mph) and posted speed limit violations were counted. Exposure-controlled rates were calculated for each of these safety events. Driver characteristics and hard braking events were compared using median tests, and Spearman correlation was used to assess the relationships among vision measurements and driving safety events. RESULTS: Twenty licensed bioptic drivers and 20 control drivers were enrolled. Bioptic drivers were significantly more likely to perform hard braking manoeuvres than controls. Among bioptic drivers, hard braking frequency was not predicted by visual acuity, contrast sensitivity or binocular integrated visual field deviation. Bioptic drivers with poorer contrast sensitivity were more likely to travel above 65 mph. Speeding events were not related to hard braking. CONCLUSIONS: Bioptic drivers demonstrated nearly three times as many hard braking events per 1000 miles driven, but vision measurements did not predict hard braking. Bioptic drivers with poorer contrast sensitivity were more likely to drive faster than 65 mph. Further work exploring relationships among vision and driving safety in bioptic drivers is warranted.

  PublisherOA PDFDOI

• Hazard Perception in Visually Impaired Drivers Who Use Bioptic Telescopes

  Translational Vision Science & Technology · 2024 · 3 citations

  1st author
  • Computer Science
  • Audiology
  • Psychology

  Purpose: Bioptic telescopic spectacles can allow individuals with central vision impairment to obtain or maintain driving privileges. The purpose of this study was to (1) compare hazard perception ability among bioptic drivers and traditionally licensed controls, (2) assess the impact of bioptic telescopic spectacles on hazard perception in drivers with vision impairment, and (3) analyze the relationships among vision and hazard detection in bioptic drivers. Methods: Visual acuity, contrast sensitivity, and visual field were measured for each participant. All drivers completed the Driving Habits Questionnaire. Hazard perception testing was conducted using commercially available first-person video driving clips. Subjects signaled when they could first identify a traffic hazard requiring a change of speed or direction. Bioptic drivers were tested with and without their bioptic telescopes in alternating blocks. Hazard detection times for each clip were converted to z-scores, converted back to seconds using the average response time across all videos, and then compared among conditions. Results: Twenty-one bioptic drivers and 21 normally sighted controls participated in the study. The hazard response time of bioptic drivers was improved when able to use the telescope (5.4 ± 1.4 seconds vs 6.3 ± 1.8 seconds without telescope); however, it remained significantly longer than for controls (4.0 ± 1.4 seconds). Poorer visual acuity, contrast sensitivity, and superior visual field sensitivity loss were related to longer hazard response times. Conclusions: Drivers with central vision loss had improved hazard response times with the use of bioptic telescopic spectacles, although their responses were still slower than normally sighted control drivers. Translational Relevance: The use of a bioptic telescope by licensed, visually impaired drivers improves their hazard detection speed on a video-based task, lending support to their use on the road.

  PublisherOA PDFDOI

• Insights Regarding Optometric Findings of CHARGE Syndrome in a Pediatric Low Vision Clinic

  Optometry and Vision Science · 2023-05-02

  article

  SIGNIFICANCE: CHARGE, named for common findings-coloboma, heart defects, atresia of choanae, retardation of growth and development, genital hypoplasia, and ear anomalies-is a frequent etiology of deaf-blindness. A retrospective review in a pediatric low vision clinic presented the opportunity to investigate ocular findings in this syndrome with variable clinical presentations. PURPOSE: This retrospective study reviewed ocular findings and visual function measures from low vision evaluations of patients with CHARGE syndrome, which may influence their multidisciplinary management. METHODS: A retrospective chart review was conducted by three examiners of 60 patients presenting with CHARGE syndrome at a pediatric low vision clinic. Visual acuity and contrast sensitivity were obtained using standard measures. Ocular alignment and cycloplegic refractive error measurements were recorded. Refractive findings were analyzed using vector analysis. Anterior and posterior segment findings were recorded. RESULTS: Patients ranged in age from 1 to 29 years and were followed up for a mean of 4.3 years. Best-corrected visual acuity ranged from no light perception to 20/20 Snellen equivalent. Characteristics of strabismus, occurring in 82% of patients, were reported. Contrast sensitivity was reduced in 52% of patients. Chorioretinal colobomas were reported in 88% of patients. The most common ocular findings included nystagmus (43%), microphthalmia (27%), iris coloboma (27%), and facial nerve palsy (23%). Refractive vector analysis revealed significant myopic progression of the spherical equivalent with age and a tendency for with-the-rule astigmatism and minimal obliquity. CONCLUSIONS: This retrospective review of a relatively large sample size for this rare condition outlined the most common ocular manifestations of CHARGE syndrome. Decreased visual acuity, myopic refractive error, strabismus, and reduced contrast sensitivity were common. Thus, careful optometric evaluation in this population is required, as these findings must be considered in appropriate clinical and habilitative management.

  PublisherDOI

• Use and Perceptions of Advanced Driver Assistance Systems by Older Drivers With and Without Age-Related Macular Degeneration

  Translational Vision Science & Technology · 2022 · 28 citations

  1st author
  • Computer Science
  • Medicine
  • Audiology

  Purpose: Advanced driver assistance systems (ADAS) have been reported to improve the safety of elderly and normally sighted drivers. The purpose of this study was to assess exposure to, perceived safety of, comfort level with, and interest in using ADAS among drivers with age-related macular degeneration (AMD). Methods: Current drivers aged 60+ years were recruited at four US sites to complete a survey about ADAS and driving habits. Frequency of use and/or perceptions of eight ADAS were investigated. An avoidance score was generated using questions about difficult driving situations. Results: The survey was completed by 166 participants (80 with AMD vs. 86 without). Participants with AMD had worse self-rated vision than those without (34% vs. 2% poor or fair rating), and drove fewer weekly miles (median [interquartile range [IQR] 30 [15 to 75] vs. 60 [30 to 121] miles, P = 0.002). Participants with AMD reported more avoidance of difficult driving situations (P < 0.001). There was no difference in the number of ADAS used by AMD status (median [IQR for AMD = 2.5 [1 to 5] vs. 3 [2 to 4] without, P = 0.87). Greater reported number of ADAS used was associated with less avoidance of difficult situations (P = 0.02). The majority perceived improved safety with most ADAS. Conclusions: Many drivers with AMD utilize common ADAS, which subjectively improve their road safety and may help to reduce self-imposed restrictions for difficult situations and mileage. Translational Relevance: Drivers with AMD are adopting readily available ADAS, for which they reported potential benefits, such as safety and less restrictive driving.

  PublisherDOI

• Head-mounted tablet device for reading and navigation in low vision

  Investigative Ophthalmology & Visual Science · 2021-06-21

  articleOpen access
  Publisher

• Evaluation of a New Device for Distance and Reading Tasks in Low Vision

  Investigative Ophthalmology & Visual Science · 2021-06-21

  articleOpen access
  Publisher

• Perceptions of Advanced Driver Assistance Systems by People with and without Age-Related Macular Degeneration

  Investigative Ophthalmology & Visual Science · 2021-06-21

  articleOpen access1st authorCorresponding
  Publisher

• Mediators of the relationship between socioeconomic status and visual acuity in age-related macular degeneration

  Investigative Ophthalmology & Visual Science · 2020-06-10 · 1 citations

  articleOpen access1st authorCorresponding
  Publisher

• SOCIOECONOMIC STATUS AND MISSED CLINICAL APPOINTMENTS IN AGE-RELATED MACULAR DEGENERATION

  Innovation in Aging · 2018-11-01 · 1 citations

  articleOpen access

  Age-related macular degeneration (AMD) is a leading cause of blindness in older adults. We have previously found that socioeconomic status (SES), as represented by educational achievement, is inversely related to visual acuity in people being treated for AMD. The purpose of this study was to evaluate possible mechanisms for this relationship in patients with AMD, specifically attendance at scheduled clinical appointments with a retina specialist, access to transportation, and having had a low vision rehabilitation examination. Methods: Visual acuity with habitual correction was measured via ETDRS chart with letter-by-letter scoring. SES was represented as highest level of education. Visual function and social support scales were administered and scored using Rasch analysis. ANOVA and Fisher’s Exact Tests were used to examine the relationships among SES, VA, and clinical and transportation variables. Results: 42 people with AMD (37% female, mean±SD age of 77 ± 10 years) were recruited from The Ohio State University retina service. 54% of subjects missed at least one appointment that was not rescheduled within a month. Missed clinical appointments were more common among low SES groups (p=0.42). Having missed an appointment was associated with older age (p=0.032) and worse self-reported visual function (p=0.029). Only 7% of subjects reported difficulty finding transportation to appointments. Conclusion: Lower SES was related to an increased likelihood of missed appointments in people with AMD, as well as poorer visual functioning. Attendance at clinical appointments may be a factor in explaining the relationship between lower SES and poor vision in people with age-related macular degeneration.

  PublisherOA PDFDOI

Frequent coauthors

• San-San Cooley

  SUNY College of Optometry

  9 shared

• Bradley E. Dougherty

  SUNY College of Optometry

  9 shared

• Alex R. Bowers

  Smith-Kettlewell Eye Research Institute

  6 shared

• Nicole Ross

  New England College of Optometry

  6 shared

• Frederick H. Davidorf

  5 shared

• B. Dougherty

  The Ohio State University

  4 shared

• Alicia M. Donahue

  NCR (United States)

  4 shared

• Thomas W. Raasch

  The Ohio State University

  4 shared

Labs

• Karla Zadnik LabPI

Awards & honors

• Fellow of the American Academy of Optometry
• Ezell Fellowships through the American Academy of Optometry…