Comments and Conclusion (cont’d)
- Although achromatopsia is thought to be a stationary disorder, on SD-OCT examination in a recent study of 40 achromats, initial features of cone cell decay were disruption of the PIL (IS/OS junction or ciliary layer) and the presence of a ‘bubble’ in the cone outer segments, followed by complete degeneration of the cone cell layer and retinal pigment epithelium. This led to the conclusion that achromatopsia is not a stationary disease but rather a slowly progressing disorder.3
- Stargardt disease is inherited as an autosomal recessive trait that is due to mutations in the ABCA4 gene. Mutations in the ABCA4 gene can also result in autosomal recessive retinitis pigmentosa and cone-rod dystrophy.9
- In a study of patients with diabetic macular edema, the presence of an intact external limiting membrane (ELM) and PIL was correlated with good visual acuity.11 However in many of our cases in which the patients have poor visual acuity, the ELM remains intact under the fovea! pit, but the PIL was absent. In our experience, an intact PIL under the fovea is highly correlated with VA but the ELM is not.12
- A mutation in the RDH5 gene has been reported in at least 6 families with autosomal recessive disorder of fundus albi and cone-dystrophy.10
- Genetic testing of many of the patients presented has begun with courtesy of Stephen Tsang, MD, Ph.D., Jonathan Greenberg, MD, and colleagues at Columbia University.