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Abstract #22451 Published in IGR 10-4
Direct microperimetry of α zone and β zone parapapillary atrophy
Rensch F; Jonas JBBritish Journal of Ophthalmology 2008; 92: 1617-1619
BACKGROUND: To examine the psychophysical correlate of α zone and β zone of parapapillary atrophy. METHODS: The study included 20 eyes of 10 patients affected by primary open-angle glaucoma and 12 normal eyes of six subjects. The parapapillary region was psychophysically examined by direct fundus microperimetry. The parapapillary atrophy was ophthalmoscopically differentiated into a peripheral α zone with pigmentary irregularities and a central β zone characterised by a good visibility of the large choroidal vessels and the sclera. RESULTS: The mean stimulus attenuation values in the β zone of parapapillary atrophy measured 1.00 (SD 2.54) dB, corresponding to an absolute scotoma. In the α zone, the mean stimulus attenuation values was 6.29 (4.82) dB, corresponding to a relative scotoma. The difference in the stimulus attenuation between α zone and β zone was statistically significant (p = 0.028). CONCLUSIONS: The psychophysical correlate of β zone of parapapillary atrophy is an absolute scotoma, and the correlate of α is a relative scotoma. It agrees with the histological correlate of β zone with a complete loss of retinal pigment epithelium cells and photoreceptors, and with the histological correlate of α zone with structural irregularities of the retinal pigment epithelium.
Dr. F. Rensch, Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Germany