Indian Journal of Ophthalmology

ARTICLE
Year
: 1969  |  Volume : 17  |  Issue : 5  |  Page : 222--225

Oguchi's disease- first report from India


Dhanwant Singh, Daljit Singh 
 Department of Ophthalmology, Medical College, Patiala, India

Correspondence Address:
Dhanwant Singh
Department of Ophthalmology, Medical College, Patiala
India




How to cite this article:
Singh D, Singh D. Oguchi's disease- first report from India.Indian J Ophthalmol 1969;17:222-225


How to cite this URL:
Singh D, Singh D. Oguchi's disease- first report from India. Indian J Ophthalmol [serial online] 1969 [cited 2024 Mar 28 ];17:222-225
Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?1969/17/5/222/38544


Full Text

Oguchi in 1912 described a form of night blindness which was associated with a diffuse greyish white discolora�tion of the fundus. Over the next few decades more than 60 cases were ob�served, mainly by Japanese authors. The first European case was described by Scheerer in 1927 and since then 24 cases of this disease have been reported from the continent. Klein in 1939 dis�cussed the first case in the United States and 4 more were reported by Gouras and Carr in 1965.

The features which differentiate most cases of this type of nyctalopia from other disorders of congenital stationary night blindness are the ap�pearance of the fundus and the fact that prolonged dark adaptation will lead to a disappearance of the abnor�mal fundus discoloration and normali�zation of all psychophysical testitng parameters (Mizuo's phenomenon). Of note also is the peculiar histological picture. The presence of a large num�ber of cones as well as a second pig�ment layer led Mann to classify this disorder as an atavistic disorder.

This paper presents three cases of Oguchi's disease that were discovered in a single family living in Patiala. Since this family was being investigat�ed, two more cases have come to our notice, one belonging to Patiala and another coming from a village in Lu�dhiana.

 Case Report



A 21 year old college girl came with the complaint that she could not adapt in the dark as well as her friends could. She was afraid that the condition might get worse. Her visual acuity was 6/6 J I in both eyes. Fundus examination showed that the optic disc was normal, but the blood vessels appeared un�usually dark and the periphery of the retina at places showed grey mottled patches. To have a better look at the periphery of the retina, homatropine was put in both the eyes and the patient made to sit in a semidarkened room with her eyes closed. Pupils did not dilate well even after 1� hours. This difficulty in getting the pupils dilated was also subsequently noticed in the other two patients. The fundus exa�mination was completely surprising�the blood vessels no longer looked dark and the peripheral mottling seen earlier had completely disappeared. These changes left us guessing if it could be a case of Oguchi's disease. The patient was reexamined next day after being exposed to daylight for 2 hours. There was no longer any doubt left [Figure 1],[Figure 2]. The fundus had a typical greyish white discoloration ex�tending from the periphery right upto the disc. The vessels appeared un�usually dark and their branchings and sub-branchings could be visualized with utmost clarity. Many vessels looked wider and fainter and tended to merge with the background (washed out appearance). At some places a vessel segment was seen to be accom�panied by a white or a dark line. The periphery of the fundus had a greyish mottled appearance, but there was no actual pigmentary disturbance. With prolonged dark adaptation lasting for about 2� hours the patient could see as well in the dark as any normal person. Her visual fields with white and colour�ed objects was normal. Colour vision was also normal.

 Examination of the Family



The patient's father and mother aged 55 and 50 were reported having no visual trouble. They were not even remotely related to each other. Out of two sisters and one brother living in Patiala, one sister aged 19 was re�ported having the same trouble. An�other sister was serving in Rajasthan and nothing was known about her con�dition: she was called back home for examination. This (27 years old) and the other (19 year old) sister were also found to be suffering from Oguchi's disease. The fundi had typical chan�ges as described in the first case [Figure 3],[Figure 4],[Figure 6]. Perimetric findings, the colour vision and secondary dark adaptation were exactly like those of our first patient.

 Discussion



Oguchi's disease is considered a rare disease and it seems that no case has so far been reported from India. The three cases reported here were dis�covered only three months back. Since then we have seen two more definite cases of Oguchi's disease, but their fa�milies remain to be investigated. Thus it seemed to us that the disease may be much more common than the pau�city of reports in the literature would suggest.

The grey white flourescent appear�ance of the fundus was considered by Oguchi to be due to breakdown of visual purple into visual yellow and visual white and also due to disper�sion of pigment from the additional pigment layer that lies between the normal pigment epithelium and the layer of rods and cones. Mizuo's phe�nomenon is due to the replacement of visual white by visual purple and the return of pigment granules into the cells.

The unusual appearances of the blood vessels need explanation. The vessels look dark due to two reasons �firstly they are no more illuminated by the red glow of the fundus and se�condly they appear darker by contrast with grey white background. The vastly improved visibility of the finer vessels also depends upon these fac�tors-the fine vessels are no more lost in the general red fundus reflex and secondly they stand out better against whitish background.

The peculiar and characteristic wash�ed out appearance [Figure 7],[Figure 8], not mentioned by previous authors can be explained as follows : The vessels are situated on the surface of the retina while their shadow is formed on the deep layers, which in these cases be�have like rough mirrors due to collec�tion of visual white in the light adapted state. The bigger the shadow the more the washed out appearance. Such sha�dows will form only when light falls on the vessel from a side (also see [Figure 1]). When the light falls along the length of the vessel, there is no such shadow.

An occasional white streak along the vessel is due to chance reflection from a vessel being re-reflected from the mirror like retina into the observer's eye.

 Summary



3 cases of Oguchi's disease in a family belonging to Patiala are describ�ed. All the patients suffered from nightblindness, showed typical greyish white fundus discoloration, well mark�ed Mizuo's phenomenon and secondary dark adaptation. A "washed out ap�pearance" of the vessels considered characteristic for this disease is des�cribed. The causation of unusually dark vessels, improved visibility of finer vessels, "washed out appearance" of vessels and white streak along some vessels are explained.[5]

References

1Elwyn. H. - Diseases of the retina, p. 305. Blackiston Company, Toronto (1947).
2Gouras, P., and Carr. R. (1965): Arch. Ophth., 73; 646.
3Klein, B. (1939)-Amer. J. Ophth. 22: 953.
4Mann, I., Developmental abnormalities of Eye, ed 2. Philadelphia: J. B. Lip�pincot Co., 1957 p. 147.
5Oguchi, C. (1912)-Griefe Arch. Ophth. 81: 109 cited in 1.