Abstract
Purpose :
Visual defects related to ocular diseases, such as diminished vision in dim lightning in patients with age-related macular degeneration (AMD), can manifest in the early phases of disease before visual acuity is even affected. Abnormalities of color perception have been identified in patients with early AMD; it has also been shown that testing color perception of early AMD patients can identify alterations in the retina. [REF: Dimitrov PN, Robman LD, Varsamidis M et al. Visual function tests as potential biomarkers in age-related macular degeneration. Invest Ophthalmol Vis Sci 2011; 52: 9457-9469.]
To identify and develop treatments before visual loss occurs, reliable functional standardized measures are required. To meet this need, we evaluated Cone Contrast Thresholds (CCT) to quantify cone-specific contrast sensitivity in healthy normal subjects and compared CCT results with conventional diagnostic measures.
Methods :
A prospective study was performed on healthy normal subjects to evaluate their color visual function. 18 participants (36 eyes) were included based on normal medical and family history and normal fundoscopic examination. Subject consent, history, visual acuity, intraocular pressure, refractive error, and eye dominance were documented. Participants were subjected to color visual function tests of each eye in randomized order. Tests included: Cone Contrast Threshold under 6 conditions with testing in triplicate (non-mydriatic, mydriatic, with use of pinholes, and neutral density filters 03, 09, and 15), Ishihara Pseudoisochromatic Color Plates, Farnsworth-Munsell 100-hue Test color arrangement, and Neitz anomaloscope.
Results :
The CCT assessment measures found changes from observed baseline (control) under conditions employing filtered lenses, pinholes, and dilated eyes. Significant reduction in CCT sensitivity values were found for patients who were dilated or using pinholes, and in patients using neutral density filters.
Conclusions :
This study supports the utility and feasibility of employing CCT to examine patients during standard care to obtain quantitative metrics of color vision function. CCT is a reliable and quantitative tool for evaluating color visual function as compared to conventional diagnostic measures. CCT should only be employed in the undilated state and pinholes should not be used to correct for refractive error.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.