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

To describe the natural history of branch retinal vein occlusion (BRVO) based on the best available evidence from the literature. Branch retinal vein occlusion is the second most frequent major retinal vascular disease. Although several new treatments for BRVO are currently being introduced, data on its natural history are sparse. English language articles were retrieved using a keyword search of MEDLINE, EMBASE, Current Contents, and the Cochrane Library to November 13, 2008, supplemented by manually searching the references of review articles published within the last 5 years. All relevant observational studies evaluating the natural history of BRVO and all clinical trials evaluating BRVO interventions with an untreated control arm were independently identified by 2 investigators. Of a total of 5965 citations retrieved, 24 eligible studies were identified and reviewed, providing 1608 eyes with BRVO with data on natural history. Visual acuity (VA) was moderately poor at baseline (<20/40). Although VA generally improved, with mean improvement ranging from 1 letter at 6 weeks to 28 letters up to 24 months, few studies reported improvement beyond 20/40. Over a 1-year period, 5% to 15% of eyes developed macular edema (ME), but of those with ME at baseline, 18% to 41% resolved. At baseline, 5% to 6% of eyes had bilateral BRVO, with 10% developing fellow eye involvement over time. There were few high-quality studies on other outcomes, including development of new vessels. Visual acuity generally improved in eyes with BRVO without intervention, although clinically significant improvement beyond 20/40 was uncommon. Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved. Show more

In branch retinal vein occlusion (BRVO), abnormal arteriovenous crossing with vein compression, degenerative changes of the vessel wall and abnormal hematological factors constitute the primary mechanism of vessel occlusion. In general, BRVO has a good prognosis: 50–60% of eyes are reported to have a final visual acuity (VA) of 20/40 or better even without treatment. One important prognostic factor for final VA appears to be the initial VA. Grid laser photocoagulation is an established treatment for macular edema in a particular group of patients with BRVO, while promising results for this condition are shown by intravitreal application of steroids or new vascular endothelial growth factor inhibitors. Vitrectomy with or without arteriovenous sheathotomy combined with removal of the internal limiting membrane may improve vision in eyes with macular edema which are unresponsive to or ineligible for laser treatment. Show more

Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations. Show more