Effects of panretinal photocoagulation on posterior fundus in diabetic retinopathy. Analysis of local macular electroretinogram and visual evoked response
Kondo, T.; Miyake, Y.
Nippon Ganka Gakkai Zasshi 89(4): 535-543
1985
ISSN/ISBN: 0029-0203 PMID: 4025059 Document Number: 253224
To evaluate the effects of panretinal photocoagulation (PRP) on electrical responses in the retina and visual pathway, 23 eyes of 18 patients with diabetic retinopathy were studied, who had been treated by PRP. The results are summarized as follows: in electroretinogram (ERG), the post-PRP amplitude reduced by 44.6% in a-wave and 41.6% in b-wave; the local macular ERG and VER were recorded simultaneously to assess the function of the posterior pole where the photocoagulation was not applied; and the macular was stimulated with 3 different spots, 5.degree., 10.degree. and 15.degree. in diameter. Following PRP, the amplitude of local ERG recorded with 5.degree. spot showed a tendency to increase, while the amplitude tended to decrease as the stimulus spots became larger. In 15.degree. spot, the reduction of the amplitude in local ERG was statistically significant (P < 0.05) after PRP. The peak time of b-wave in local ERG did not show any significant difference between pre- and post-PRP in either stimulus spot. The amplitude and peak time of local VER did not show any significant difference between pre- and post-PRP in either stimulus spot. Patients with decreased visual acuity following PRP showed the reduction of the amplitude of local ERG, particularly recorded with 5.degree. spot. Retinal damage in the macular area may be subsequent to PRP in some cases, resulting in the reduction of amplitude in local macular ERG. Many cases did not show any significant change or rather increase of amplitude in local macular ERG, suggesting some recovery of function in the macular area.