Evaluation of acquired color vision deficiency in retinal vein occlusion using the Rabin cone contrast test.

PURPOSE: To investigate acquired color vision deficiency (CVD) using the Rabin cone contrast test (RCCT) in patients with retinal vein occlusion (RVO). METHODS: We retrospectively evaluated 39 patients with macular edema due to RVO who were treated with intravitreal injections of anti-VEGF agents and demonstrated improvement of best-corrected visual acuity to 20/20 Snellen VA or better. The acquired CVD was evaluated by the RCCT and standard pseudo-isochromatic plates-part 2 (SPP-2). RESULTS: Mean L, M, and S color contrast test (CCT) scores were significantly lower in RVO eyes than in the fellow eyes (L CCTs, 70.0 ± 13.3 vs. 90.0 ± 8.0, respectively, P < 0.01; M CCTs, 85.0 ± 16.6 vs. 95.0 ± 5.7, respectively, P < 0.01; S CCTs, 80.0 ± 21.5 vs. 95.0 ± 7.1, respectively, P < 0.01). Acquired CVD was diagnosed in 25 eyes of 39 patients by the RCCT and in 15 eyes of 39 patients by SPP-2. The RCCT was performed on two different days in 21 patients. It revealed acquired CVD in 17 eyes on the first day and in 10 eyes on the second day. Acquired CVD was improved in 9 eyes, unchanged in 8 eyes, and worsened in 2 eyes. CONCLUSIONS: The RCCT revealed eyes with RVO had acquired CVD. Acquired CVD caused by RVO can be improved further in some cases even after recovery of vision to 20/20. The RCCT may be able to quantitatively diagnose acquired CVD status.

Longitudinal Evaluation of Visual Function Impairments in Early and Intermediate Age-Related Macular Degeneration Patients.

Purpose: To evaluate visual function (VF) changes in early and intermediate age-related macular degeneration (eAMD and iAMD) over 24 months. Design: Prospective, observational natural history study. Participants: Participants were enrolled at the Duke Eye Center. Methods: A total of 101 subjects (33 with eAMD, 47 with iAMD, and 21 normal controls) were recruited. Visual function (VF) tests included best-corrected visual acuity (BCVA), low- luminance visual acuity (LLVA), microperimetry (MP), cone contrast tests (CCTs), and dark adaptation (DA). Mixed-effect model repeated measures based on absolute values and change from baseline identified VF tests differentiating AMD from controls and revealing longitudinal VF decline when controlling for covariates (baseline value, age, coronary artery disease, dry eye, and phakic status). Nine AMD genetic risk variants, combinations of these (genetic burden score), reticular pseudodrusen (RPD), and hyperreflective foci (HRF) were tested as predictors of diagnosis and VF performance. Main Outcome Measures: Longitudinal changes in VF metrics over 24 months. Results: A total of 70 subjects completed the 2-year visit (22 with eAMD, 31 with iAMD, and 17 controls). Percent reduced threshold (PRT) on MP and CCT red significantly distinguished iAMD versus controls after 12 and 24 months, respectively. Cone contrast test red, PRT, and absolute threshold (AT) on MP showed significant longitudinal deterioration of VF in iAMD versus baseline at 12 months and onward, however, with a reduced rate of worsening. The DA data confirmed a preexisting functional deficit in iAMD at baseline and revealed an increasing proportion of poorly performing iAMD subjects in DA over the study period. None of the other VF measures showed consistent significant changes among the normal, early, and intermediate groups or over time. The genetic burden score was significantly associated with AMD diagnosis (relative risk for iAMD = 1.64, P < 0.01) and DA (r = 0.42, P = 0.00005). Reticular pseudodrusen and HRF showed moderate associations with DA and weak to moderate associations with MP variables. Conclusions: In iAMD, MP variables, CCT red, and DA revealed slow and nonlinear functional decline over 24 months. A structure-function relationship in eAMD and iAMD stages was demonstrated among HRF, RPD, and DA, possibly modified by genetic risk factors. These structural and functional features represent potential end points for clinical trials in iAMD.

Quantifying Color Vision Changes Associated With Cataracts Using Cone Contrast Thresholds.

Purpose: To evaluate effects of age and simulated and real cataractous changes on color vision as measured by the high-definition cone contrast test (CCT). Methods: Twenty-four healthy volunteers from two cohort studies performed CCT using best-corrected visual acuity, filters, mydriasis, and pinhole correction. Retrospective cross-sectional study of patients seen in eye clinics evaluated the relationship between age and color vision, and age and lens status in 355 eyes. Last, 25 subjects underwent CCT before and after cataract surgery. Results: CCT scores were most reliable in the nonmydriatic condition without pinhole correction. Progressively dense brown filters produced small decreases in S-cone sensitivity. Linear regression analysis of phakic subjects showed a decline for all cone classes with age. Rate of decline was greater for S-cones (slope = -1.09; 95% confidence interval [CI], -1.30 to 0.86) than M-cones (slope = -0.80; 95% CI, -1.03 to -0.58) and L-cones (slope = -0.66; 95% CI, -0.88 to -0.44). CCT scores increased for S-cones but reduced for L- and M-cones in pseudophakic subjects compared with phakic patients. CCT scores after cataract surgery increased for S-cones, M-cones, and L-cones by 33.0 (95% CI, 8.6 to 57.4), 24.9 (95% CI, 3.8 to 46.0), and 22.0 (95% CI, -3.2 to 47.3), respectively. Conclusions: CCT assessment allows for clinically practical quantitation of color and contrast vision improvement after cataract surgery and aging patients who note poor vision despite good visual acuity. Translational Relevance: CCT testing, which quantifies hereditary and acquired color deficiency, can also quantify the degree of cataract severity and, combined with other parameters, can provide more precise guidance for cataract extraction to optimize patient care.

Evaluation of clinical validity of the Rabin cone contrast test in normal phakic or pseudophakic eyes and severely dichromatic eyes.

PURPOSE: To evaluate the clinical validity of the Rabin cone contrast test (RCCT; Innova Systems, Inc.) in patients with normal phakic/pseudophakic eyes and severe dichromatic colour vision deficiency (CVD). METHODS: We evaluated age-related changes in the RCCT scores in 166 phakic eyes and 34 pseudophakic eyes and the RCCT sensitivity and specificity in 28 men with severe dichromatic CVD (10 with protanopia, 18 with deutanopia) and nine age-matched controls. All participants had 20/20 or better Snellen best-corrected visual acuity (BCVA). The RCCT was used to measure the L, M and S-CCT scores (range, 0-100). RESULTS: In normal phakic eyes, the mean L, M and S-CCT scores decreased gradually with ageing, with normal levels in patients in the second to seventh decades of life and some below normal in the eighth and ninth decades of life. In normal pseudophakic eyes, the mean L, M and S-CCT scores were normal in patients in the seventh to ninth decades of life. In eyes with severe CVD, the mean L, M and S-CCT scores were, respectively, 31.5 ± 18.3, 86.0 ± 12.6 and 98.0 ± 6.3 in patients with protanopia; 92.8 ± 10.5, 50.8 ± 19.6 and 97.8 ± 5.2 in patients with deutanopia; and 99.4 ± 1.7, 98.3 ± 5.0 and 99.4 ± 1.7 in controls. The RCCT sensitivity and specificity were 100% for diagnosing the CVD type. CONCLUSION: The RCCT can be used in non-visually impaired patients up to the seventh decade of life and after cataract surgery in elderly patients. The RCCT is available for CVD screening and typing and the score has a wide distribution range even in patients with severe CVD.

Effects of repetitive low-level blast exposure on visual system and ocular structures.

UNLABELLED: The purpose of this study was to determine whether repetitive exposure to low-level blasts during military breacher training produces acute and cumulative damage to the ocular tissues or visual system. The effects of low-level blast exposure on high-contrast visual acuity, contrast sensitivity, oculomotor function, color vision, visual field (VF), pupillary light reflex, corneal endothelial cell density (ECD), macular thickness, retinal nerve fiber layer thickness, and cup-to-disc ratio were assessed using a battery of standard clinical ophthalmic tests administered 10 times over a 2-year period. Data from nine breacher instructors (Cadre) were compared with data from four breacher engineers (CONTROL). The Cadre group showed higher vertical deviation at near than the CONTROL group over time. The VF mean deviation on the left eye that tended to be worse in the Cadre group was worse throughout the study, suggesting a decrease in VF sensitivity (Cadre: -0.20 +/- 0.15 dB; CONTROL: 1.05 +/- 0.15 dB; p = 0.03). The Cadre group had a reduced ECD (right eye: Cadre 2,502 cells/mm(2) vs CONTROL 2,808 cells/mm(2), p = 0.05; left eye: Cadre 2,558 cells/mm(2) vs CONTROL 2,892 cells/mm(2), p = 0.04). These results suggest that even low-level primary blast has the potential to produce occult eye injury.