Title
PROGRESSIVE CONE DYSTROPHY: A RARE CASE REPORT
Introduction
Cone dystrophy (CD) is a term used to describe a group of eye disorders that affects the cone cells of the retina, either inherited or spontaneous appearance. Mutations have been described in about 12 genes and the three Mendelian inheritance patterns were found. It can be divided into stationary and progressive disease. In the first one, symptoms arise at birth or in youth. On the other hand, in the second one symptoms progressively become worse over time and can cause completely blindness. There is a huge variety of symptoms and the amount of vision loss is difficult to predict. As cone cells are involved with fine detailed vision, such as reading or recognizing faces, and with color perception, patients complains are related to that. CD diagnose is clinically suggested by progressive visual acuity loss and inability of color discrimination, associated with day blindness and photophobia. Fundoscopy may show a bilateral symmetric macular atrophy. Diagnosis can be confirmed with electroretinogram (ERG) test.
Methods
Medical record review
Results
We report the case of 57 years old male complaining of progressive visual acuity loss started 4 years before. Best visual acuity (BVA) was 20/400 in the right eye and 20/200 in the left eye. Fundoscopy showed a pale disc, decreased macular brightness and constricted arterioles. Electroretinogram showed a subnormal result in both eyes and nonrecordable photopic ERG. After diagnosed cone dystrophy disorder, the patient was instructed about his condition and adequate follow-up was provided.
Discussion
CD should not be confused with congenital color blindness, in which there is no retinal degeneration associated, only color deficits. There are a few differential diagnosis to be considered. Up to now, there is no treatment or cure for CD. Treatment is directed to symptoms control, such as using tinted lenses or dark sunglasses in order to reduce photophobia and using magnifying devices to ensure better quality of life.
Keywords
- Cone dystrophy - Retinal diseases - Retina
Area
CLINICAL CASE
Authors
Gabriella Marranghello Mingione, Andréia Novelli, Guilherme Daher G M Reis, Paulo Henrique Horizonte, Beatriz Mello Mencaroni, Farid José Thomaz Neto, Mariana Rocha Martini, Andre Marcelo V. Gomes