Dr.Hemmanth Raj M, M18795, S. Murali Krishnan, Dr.Saravana Sankar P, Dr. S V Chandrakumar
40 year old male, presented to OPD with predominant complaints of defective vision since childhood both for distance and near.
There was history of photophobia and defective dark adaptation since childhood. General Examination was within normal limits. BCVA OU 6/36 NIG NIP; Slit Lamp examination revealed a normal anterior segment with no afferent pupillary reaction with early lens changes. OU – Visual Fields – Normal; OU – Color Vision – Defective; Dilated Fundus examination revealed OU – Clear media with minimal pallor of the optic disc; attenuated vessels and pigmentary mottling in macula.
Electrophysiological studies (ERG) showed: Implicit time shift at the 30 Hz flicker response with delayed a and b waves with decreased amplitude. All the above findings narrowed down to a diagnosis of Cone Dystrophy. With a prevalence of 1 in 40,000, the above case is presented for its rarity.