---

A rare case of oguchi disease exhibiting the classic Mizuo-Nakamura phenomenon

---

Short Communication

Author Details : Nischala Balakrishna*, Alhaj F Tasneem, Vittal I Nayak, Nagalakshmi Narayanaswamy, Sara Nastain

Volume : 6, Issue : 4, Year : 2020

Article Page : 660-663

https://doi.org/10.18231/j.ijceo.2020.141

Suggest article by email

Get Permission

---

Abstract

Introduction: Oguchi disease also called congenital stationary night blindness is an autosomal recessivegenetic condition first identified in Japan with a few cases reported in other countries like Europe, America, India and Pakistan. We report one such case exhibiting the Mizuo-Nakamura phenomenon with a reduced amplitude on the b-wave of the rod electroretinogram advocating this diagnosis.
Case Report: A 40-year-old man presented with complaints of non-progressive decrease in vision as the day progressed for 6 months with normal vision during the day in both eyes. There was no history of trauma or any other ocular or systemic disease. His parents had a second-degree consanguineous marriage and his father experienced similar symptoms. Visual acuity for distance was 6/6 and N6 for near in both eyes. His anterior segment and posterior segments were normal. When the patient was put to dark adaptation for 3 hours, there was a change in his fundus background colour from grey to red (Mizuo-Nakamura phenomenon). The b-wave amplitude was decreased on the rod electroretinogram. The cone electroretinogram on the other hand was normal. All this was confirmed by his genetic study which favoured this diagnosis.
Conclusion: This disease presents with features similar to retinitis pigmentosa in terms of mutations in the SAG gene. This highlights the importance of the Mizou-Nakamura phenomenon in formulating a confirmatory diagnosis and treatment protocol.

Keywords: Congenital stationary night blindness, Mizuo-Nakamura phenomenon, Oguchi disease, Rod electroretinogram.

How to cite : Balakrishna N , Tasneem A F , Nayak V I , Narayanaswamy N , Nastain S , A rare case of oguchi disease exhibiting the classic Mizuo-Nakamura phenomenon. Indian J Clin Exp Ophthalmol 2020;6(4):660-663

This is an Open Access (OA) journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.