Sildenafil citrate, is an oral tablet demonstrating efficacy for maintaining an erection in males with erectile dysfunction by inhibiting phosphodiesterase type 5 (PDE5). In the present study, we report 1 case of a transient color anomaly with visual field defect after an overdose of sildenafil citrate.

One patient, a 39-year-old female, with no significant medical history other than previous major depressive disorder, visited an outpatient department due to the visual field defect that began after taking 30 tablets of sildenafil citrate (50 mg) 3 days earlier. A number of ophthalmologic tests were administered including visual acuity test, color vision test, fundus photography and the measurement of retinal structure with optical coherent tomography and her condition was monitored. The best corrected visual acuity was 1.0 in both right and left eyes in her first visit. The color anomaly and a central scotoma of both eyes were detected in the visual field test, while significant signs were not observed after evaluation using optical coherent tomography and fundus photography. After 5 weeks, the visual acuity was not affected, the color anomaly symptom disappeared and the focal visual field defect was present although improved.

Transient color anomaly and persistent central scotoma caused by an overdose ingestion of sildenafil has not been reported in Korea, The related mechanisms may involve the inhibition of PDE5 on ganglion cells and bipolar cells in the retina and interruption of phosphodiesterase type 6 (PDE6) function in both rods and cones.