Article
Assessment of retinal funtion during treatment with Sildenafil
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Published: | September 22, 2004 |
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Outline
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Objective
Sildenafil citrat (Viagra®) is mainly an inhibitor of phosphodiesterase type 5 (PDE5) in smooth muscle cells. Ophthalmological side effects are possible because there is also an inhibitory effect on PDE 6 of retinal photoreceptors. We wanted to find out if there are any effects on retinal function measured with the Ganzfeld-ERG and the multifocal ERG (mfERG) during treatment with sildenafil.
Methods
16 eyes from 8 patients (age 37.0 ± 8.2 years) were examined before and 3 months after start of treatment with sildenafil (3x50mg/d oral dose; reason for treatment: pulmonary hypertension). With the Ganzfeld-ERG, the 5 standard responses (photopic and scotopic) were recorded. Concerning mfERG, the First-Order Kernel (FOK) was recorded and the responses obtained from five different concentric rings for amplitude (nV/deg2, voltage difference between first trough and first peak of the scaled template) and implicit time (ms) for the FOK were summed. Statistics: Wilcoxon matched pairs signed rank test.
Results
There were no statistically significant differences for the amplitudes and implicit-times of the a- and b-wave in the Ganzfeld-ERG (cone response, a-wave before/after 3 months: amplitude 42.4/45.0uV, implicit time 14.1/13.3ms). Amplitudes were decreasing with increasing retinal eccentricity, while there were no statistically significant differences for all rings between measurements before and 3 months after start of treatment; median values for ring 1 (nV/deg2 , before/ 3 months after start of treatment) 106.5/ 108. There also were no statistically significant differences for the implicit times for all rings; ring 1 (ms): 35.7/ 35.4.
Conclusions
Treatment with sildenafil did not show any statistically significant changes of Ganzfeld-ERG and mfERG suggesting that there is no negative effect of sildenafil at least concerning the photopic and scotopic response of the retina 3 months after start of treatment.