Faculty Bibliography

SIGNIFICANCE/CONCLUSIONS:Systematic lighting assessments should be part of low vision evaluations. The LuxIQ has gained popularity as an assessment tool, but its reliability has not been examined independently and is necessary for evidence-based vision rehabilitation. PURPOSE/OBJECTIVE:Besides magnification, improved lighting levels are a common intervention in reading rehabilitation for individuals with low vision. Determining the appropriate lighting can be a complex and time-consuming task. The LuxIQ is a portable lighting assessment tool that can be used to systematically measure lighting preferences; however, there is little independent evidence to support its reliability in low vision rehabilitation. METHODS:One hundred nine control subjects (age, 18 to 85 years) and 64 individuals with low vision (age, 27 to 99 years) adjusted both the luminance and color temperature parameters on the LuxIQ while viewing a sentence on the MNREAD at their preferred print size for continuous reading. After 30 minutes, they were asked to repeat the same measurements. RESULTS:Using Bland-Altman plots, test-retest variability was calculated using the limits of agreement (LOAs). For illuminance, the LOA width was 2806 lux for control subjects and 2657 lux for visually impaired participants. For color temperature, the LOA width was 2807 K for control subjects and 2364 K for those with a visual impairment. Difference scores were centered near zero, indicating overall accuracy. CONCLUSIONS:The measurement of lighting preference lacks the precision necessary for clinical utility, given that the LOA for luminance ranged more than 2600 lux, with normally sighted and low vision participants. Such variability translates into a range of approximately ±40 or 50 W in an incandescent light bulb, depending on the luminance level, making it clinically difficult to narrow down the options for evidence-based lighting recommendations. Next steps are to examine whether the reading behavior of low vision clients is positively affected by interventions that are based on LuxIQ recommendations.

SIGNIFICANCE/CONCLUSIONS:Fundus-guided perimetry is a common clinical tool used to measure visual field sensitivities. Comparisons between perimeters are often made despite relative differences in hardware parameters. We directly compared two perimeters using Weber contrast, which allowed us to assess the clinical gain associated with the extended stimulus range of the macular integrity assessment (MAIA). PURPOSE/OBJECTIVE:The purpose of this study was to directly compare sensitivity thresholds for two microperimeters, the MAIA and Optos optical coherence tomography/scanning laser ophthalmoscope, using Weber contrast values. We also examined the clinical utility of the extended stimulus range of the MAIA. METHODS:Six normally sighted adults with no visual field loss and 16 adults with low vision were recruited. Thresholds were measured on the MAIA and Optos using the same threshold algorithm and test points. To compare equivalent units, decibel thresholds were converted to light increments in apostilbs and then to delta increment intensities relative to each instrument's background luminance. Repeatability was assessed for normally sighted adults by testing both instruments on 3 separate days. RESULTS:For normally sighted observers, mean thresholds were similar on both instruments, and repeatability within microperimeters was high. The MAIA has a 0.3-log lower contrast range and 1.37 higher contrast range. The lower contrast values did not result in lower thresholds for the normally sighted observers on the MAIA. There was a 25% increase in the number of measurable thresholds owing to the higher contrast values in low-vision observers. CONCLUSIONS:The higher contrast range in the MAIA yielded only a small increase in detectable thresholds for participants with visual field loss.

OBJECTIVE:We sought to determine under what conditions brighter lighting improves reading performance. METHOD:Thirteen participants with typical sight and 9 participants with age-related macular degeneration (AMD) read sentences ranging from 0.0 to 1.3 logMAR under luminance levels ranging from 3.5 to 696 cd/m². RESULTS:At the dimmest luminance level (3.5 cd/m²), reading speeds were slowest at the smaller letter sizes and reached an asymptote for larger sizes. When luminance was increased to 30 cd/m², reading speed increased only for the smaller letter sizes. Additional lighting did not increase reading speeds for any letter size. Similar size-related effects of luminance were observed in participants with AMD. CONCLUSION:In some instances, performance on acuity-limited tasks might be improved by brighter lighting. However, brighter lighting does not always improve reading; the magnitude of the effect depends on the text size and the relative changes in light level.

PURPOSE/OBJECTIVE:To examine whether individuals with Stargardt disease macular dystrophy (STGD) change the location of fixation with instruction. DESIGN/METHODS:Case-control study. PARTICIPANTS/METHODS:Thirteen normally sighted and 37 STGD participants. METHODS:Using an Optos scanning laser ophthalmoscopy/OCT microperimeter (Optos plc, Dunfermline, UK), fixation was measured under 2 different instructions: "look at the cross" (LC) and "look straight ahead, even if you do not see the cross" (LS). Visual acuity, contrast sensitivity, disease duration, and age at disease onset were obtained from medical records. MAIN OUTCOME MEASURE/METHODS:Change in fixation with instruction. RESULTS:Mean age of the STGD participants was 39.2 years, and 24 were women. Mean acuity was 1.01±0.29 logarithm of the minimum angle of resolution (logMAR), and mean contrast sensitivity was 1.16±0.41 log. The largest number of fixations under the LC condition were in the superior retina. Patients with STGD were divided into 3 groups, depending on the change in fixation locus when asked to look straight ahead: those having fixation closer the fovea, those with no change in the location of fixation, and those looking farther away from the fovea. Fifty-one eyes of 32 participants had fixations closer to the fovea when asked to look straight ahead (average change, -6.3°), whereas 13 eyes of 11 participants did not change fixation. There were no significant differences between groups in age, visual acuity, contrast sensitivity, bivariate contour ellipse area, and age at disease onset. CONCLUSIONS:Despite having eccentric fixation, most STGD participants did not have a complete directional re-referencing from the fovea to the eccentric location, and moved fixation when asked to look straight ahead. This finding emphasizes that reliable assessment of visual function during evaluations of disease progression or in therapeutic intervention trials requires consistent instructions and monitoring of fixation. Otherwise, a patient's interpretation of fixation instruction may confound the results.

Purpose: Previous research has demonstrated that oculomotor control training results in increased reading speed in patients with central scotomas due to retinal disease. Typically, reading-eye-movement training takes place in clinical settings and is executed by a therapist who provides guidance and immediate performance feedback. In-home vision rehabilitation has the potential to reduce travel, and expenses for patients and allow more frequent training. This study validated the effectiveness of an interactive, self-guided eye movement training program that could be independently used in the home. Methods: Eight subjects with central scotomas due to retinal disease participated in the 8-week study. The median age of subjects was 51 years (range, 25-94 years). Binocular visual acuity ranged from 20/80 to 20/400, and contrast sensitivity ranged from 0.56-1.88 log CS. Subjects performed eye movement training tasks once per week for one hour on a user-friendly computer platform, developed using methods from our previous research. The interface is fully accessible, consisting of large icons, touch-screen displays, speech recognition, and voice controls. The platform allows participants to self-administer training exercises by automatically selecting appropriate modules based on past training performance, executing the training exercise, and storing training data. The binocular training program advances from single- to three-letter word saccades and progressed from small saccades to larger eye movements. All subjects were trained to navigate the program and were required to demonstrate proficiency before beginning independent training. Outcome measures (MNREAD, visual acuity, contrast sensitivity, microperimetry thresholds) were assessed at baseline, 1 month, and post-training. Results: Mean reading speed at baseline was 69.3 wpm. Reading speed increased by an average of 44.2 wpm (63.7%) after 8 weeks of self-guided eye-movement training. Improvement in reading speed was independent of age, acuity, contrast sensitivity, and reading speed at baseline (p<.05). Conclusions: Consistent with our previous work, a computer platform designed for independent training of eye-movement control increased reading speed in subjects with central scotomas due to retinal disease. Our findings suggest that the platform could be effectively used for automated, in-home training

Background. Parkinson's disease (PD) progressively affects dopaminergic neurotransmission and may affect retinal dopaminergic functions and structures. Objective. This 2-year randomized, open-label, parallel-group, flexible-dose study, NCT00144300, evaluated ophthalmologic safety profiles of immediate-release (IR) pramipexole and ropinirole in patients with early idiopathic PD with