97th DOG Annual Meeting 1999

P512

A DIFFERENTIAL DIAGNOSTIC APPROACH TO CONGENITAL ACHROMATOPSIA: APPLICATION IN TWO CLINICAL CASES

A. Farkas, K. Wenzel', R. Vamos, J. Gyory


Purpose: To investigate the possibility of differential diagnosis of congenital achromatopsia through analysis of two cases.

Patients and Methods: Clinical, psychophysical and electrophysiological examinations were carried out in two (31 years old male and 58 years old female) patients with achromatopsia.The clinical test battery comprised visual acuity, anterior segment and fundus examination. Psychophysical tests were color vision, spectral sensitivity, dark adaptation, perimetry and CFF. The electrophysiological test used was ERG.

Results: The clinical examinations demonstrated classical signs of achromatopsia in both patients. The psychophysical examinations revealed a considerable difference in the spectral sensitivity curves of the two patients. The maximum of the spectral sensitivity curve was found at 507 nm in the first case, which corresponds to that of the rods. This case was considered a complete achromatopsia. The second case showed maximal spectral sensitivity at 527 nm, a value between that of the rods and the MWS cones. This case would appear to be an incomplete achromatopsia.

Conclusions: Consideration of spectral sensitivity is essential in the differential diagnosis of patients with congenital achromatopsia and is suitable for differentiating complete and incomplete forms of the disease.

2nd Dept. of Ophthalmology, Semmelweis University of Medicine, Budapest, Hungary (H-1085 Budapest Maria Str. 39.)
'Dept. of Precision Mechanics and Optics, Technical University of Budapest, Hungary


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