When Erectile Dysfunction Therapy Clouds the Vision: ST-BRVO after Sildenafil in a Healthy Male

Abstract

Introduction

Sildenafil, a widely prescribed phosphodiesterase-5 (PDE5) inhibitor for erectile dysfunction, is generally well tolerated. However, ocular vascular complications – including non-arteritic anterior ischemic optic neuropathy, central serous chorioretinopathy, and retinal vein occlusion (RVO) – have been reported. Though rare, such events can occur even in individuals without conventional systemic risk factors.

Case Presentation

A 55-year-old man with no prior medical history developed sudden, painless visual blurring in his right eye 48 h after ingesting a single 100 mg dose of sildenafil. Clinical evaluation revealed a superotemporal branch RVO with macular edema. A comprehensive systemic and hematologic workup, including thrombophilia screening and cardiac evaluation, yielded normal results. The patient was treated with an intravitreal injection of bevacizumab, leading to anatomical and visual improvement.

Conclusion

This case draws attention to a possible association between sildenafil use and retinal vascular events, particularly BRVO, even in healthy individuals. The temporal proximity and absence of systemic risk factors suggest a potential dose-independent vascular susceptibility. Clinicians should be aware of this rare but potentially vision-threatening complication.

Introduction

Sildenafil citrate, a selective PDE5 inhibitor, is commonly prescribed for erectile dysfunction and pulmonary arterial hypertension. It exerts its effect by enhancing the nitric oxide-cyclic guanosine monophosphate signaling pathway, leading to vasodilation and smooth muscle relaxation [1]. Although generally safe, increasing evidence suggests potential ocular side effects, including NAION, central serous chorioretinopathy, central and branch retinal vein occlusions (BRVO), and central retinal artery occlusion [2–6].

Notably, sildenafil has also been implicated in systemic vascular events such as myocardial infarction, stroke, and pulmonary embolism, especially in predisposed individuals [7, 8]. A case of pulmonary embolism leading to a BRVO following sildenafil use was previously reported, highlighting the systemic vascular effects of the drug even in otherwise asymptomatic individuals [9].

Ocular vascular side effects may be underreported or misattributed due to their rare and idiosyncratic nature. While most cases of BRVO are associated with systemic conditions like hypertension or diabetes, reports of retinal vascular events following PDE5 inhibitor use in patients without traditional risk factors warrant further attention.

Here, we report a rare case of superotemporal branch retinal vein occlusion (ST-BRVO) in a healthy, middle-aged male following the first-time use of a standard 100 mg dose of sildenafil. The absence of systemic comorbidities or hematologic abnormalities points toward a possible unpredictable vascular response to the drug.

Case Report

A 55-year-old male with no known systemic comorbidities presented with sudden, painless blurring of vision in his right eye for the past 2 days. The visual symptoms began approximately 48 h after the patient ingested a single 100 mg dose of sildenafil citrate, which he had taken for the first time to enhance libido. He denied any prior history of similar visual disturbances. His past medical history was unremarkable with no known history of hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, or clotting disorders. There was no history of recent systemic illness, dehydration, vigorous exercise, sexual act, or weight lifting, and he denied tobacco use, alcohol consumption, smoking, or use of any other medications or recreational drugs. Family history was noncontributory, with no known thrombotic or cardiovascular disorders.

On ophthalmic examination, best-corrected visual acuity in the right eye was 6/24p, improving to 6/18p with pinhole correction; the left eye had normal visual acuity of 6/6. Anterior segment examination was unremarkable in both eyes with a quiet anterior chamber, clear lens, and no relative afferent pupillary defect. Dilated fundus examination of the right eye revealed findings consistent with an ST-BRVO (Fig. 1).

Fig. 1.

Fundus photograph of right eye showing superotemporal branch retinal vein occlusion (ST-BRVO) with macular edema.

The superotemporal quadrant showed dilated and tortuous retinal veins accompanied by multiple flame-shaped and blot hemorrhages along the affected vascular arcades. Several cotton-wool spots were observed in the corresponding region, suggestive of localized retinal ischemia. Notably, the macula was edematous with loss of foveal contour, indicating involvement of the macular region (Fig. 2). The optic disc margins were well defined, without signs of swelling or pallor. The left eye fundus was within normal limits, showing a healthy pink optic disc with a cup-to-disc ratio of 0.3, normal vasculature, and an intact foveal reflex.

Fig. 2.

Fundus photograph of right eye showing superotemporal branch retinal vein occlusion (ST-BRVO) with macular edema.

Intraocular pressures measured by noncontact tonometry were 12 mm Hg in the right eye and 14 mm Hg in the left eye. Optical coherence tomography of the right eye confirmed the presence of significant intraretinal fluid in the macula, consistent with cystoid macular edema secondary to BRVO (Fig. 3).

Fig. 3.

OCT (optical coherence tomography) macula showing macular edema.

Given the patient’s lack of systemic risk factors, a thorough systemic and hematologic workup was initiated to evaluate for underlying prothrombotic states. Laboratory investigations including serum homocysteine levels, urinary homocysteine, protein C, protein S, antithrombin III levels, and genetic testing for factor V Leiden mutation were all within normal limits. Sildenafil serum levels could not be assessed due to nonavailability of the assay. Additional cardiovascular investigations including an ECG, echocardiogram, and carotid Doppler imaging did not reveal any abnormalities.

The patient received two intravitreal injections of bevacizumab (1.25 mg/0.05 mL) in the right eye to address the macular edema. On 4 months follow-up, there was marked anatomical improvement on optical coherence tomography with resolution of intraretinal fluid and corresponding functional improvement in visual acuity to 6/9 (Fig. 4–6).

Fig. 4.

OCT (optical coherence tomography) macula showing decrease in macular edema after giving 1st dose of intravitreal injection of bevacizumab.

Fig. 6.

Fundus photograph of right eye showing resolved macular edema.

Fig. 5.

OCT (optical coherence tomography) macula showing decrease in macular edema after giving 2nd dose of intravitreal injection of bevacizumab.

This case highlights a rare occurrence of BRVO in an otherwise healthy individual following sildenafil intake. While causality cannot be definitively established, the temporal association in the absence of systemic vascular risk factors suggests a potential link that warrants further investigation and clinician awareness.

Discussion

BRVO typically occurs in individuals with systemic vascular risk factors such as hypertension, diabetes, or hyperlipidemia. However, in younger or healthy individuals without such risk factors, alternative triggers must be considered. Many cases of retinal vein occlusion were seen after uptake of sildenafil due to acute intraocular pressure elevation, when combined with a Valsalva maneuver during sexual act, but in present case, the patient denies the history of indulging in recent sexual activity. Furthermore, on detailed slit-lamp examination, there were no signs suggestive of an acute IOP rise such as iris pigments on lens or endothelium, glaukomflecken, or other acute angle closure features like pain, redness, shallow anterior chamber. On fundus examination, no preretinal hemorrhage was seen. Taken together, both the clinical history and ocular findings argue against the likelihood of an acute IOP spike contributing to the retinal vein occlusion in this patient. In our case, the close temporal relationship between sildenafil intake and BRVO onset, combined with an otherwise negative systemic workup, raises suspicion of a drug-induced vascular event.

Sildenafil acts by inhibiting PDE5 and enhancing nitric oxide-cyclic guanosine monophosphate-mediated vasodilation. While systemic vasodilation is generally beneficial, in the retinal circulation it may transiently reduce perfusion pressure or induce venous congestion, particularly in anatomically predisposed eyes. The retinal circulation is an end-arterial system with limited autoregulatory capacity, making it susceptible to perfusion changes [10].

Hypothetically, sildenafil-induced vasodilation may precipitate venous stasis, promote turbulent flow, or elevate hydrostatic pressure in retinal capillaries. These conditions may predispose to thrombus formation, especially in the absence of systemic compensation. Additionally, some experimental studies have suggested transient platelet dysfunction or endothelial disruption following PDE5 inhibition [11].

Although sildenafil-related ocular vascular events are rare, several reports describe similar complications. Cunningham et al. reported BRVO in a healthy 32-year-old shortly after sildenafil use [2]. Vaziri and Moshfeghi documented central retinal vein occlusion in a 54-year-old with no clotting abnormalities [3], while Paris et al. noted a case of central retinal artery occlusion in a 46-year-old post-sildenafil intake [4]. Furthermore, Fraunfelder et al. identified over 40 cases of NAION potentially associated with PDE5 inhibitors in a pharmacovigilance review [5].

Beyond the eye, sildenafil has been implicated in thromboembolic complications including pulmonary embolism [7, 9]. These vascular events raise concerns about a shared mechanism involving vascular tone dysregulation or an idiosyncratic prothrombotic response. In our case, no systemic procoagulant state could be identified, suggesting the possibility of a dose-independent and unpredictable vascular susceptibility.

This case underscores the need for clinician awareness regarding possible ocular vascular complications of sildenafil, even with first-time or low-dose use. Patients should be advised to seek prompt ophthalmic evaluation if they experience visual symptoms following PDE5 inhibitor use.

Conclusion

Sildenafil is widely regarded as safe, yet it may have unpredictable vascular effects in certain individuals. This case of ST-BRVO following a single 100 mg dose in a healthy man without risk factors suggests the need for heightened awareness and further research into the ocular vascular implications of PDE5 inhibitors. Early recognition and treatment with intravitreal anti-VEGF agents can lead to favorable outcomes. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000548573).

Statement of Ethics

Ethical approval is not required for this study in accordance with local or national guidelines. This case report was performed in accordance with the Declaration of Helsinki. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

This study was not supported by any sponsor or funder.

Author Contributions

Dr. Nilesh Giri critically revised the manuscript for important intellectual content. Dr. Deepaswi Bhavsar contributed to the conception and design of the case report. Dr. Renu Magdum conducted review of literature and conception of discussion. Dr. Harshita Kashyap performed the clinical evaluation, prepared the initial draft of the manuscript, and assisted in the interpretation of clinical findings. Dr. Himani Yadav contributed in collection of the data and was involved in the management of the patient.

Funding Statement

This study was not supported by any sponsor or funder.

Data Availability Statement

The data that support the findings of this study are not publicly available due to privacy reasons but are available from the corresponding author upon reasonable request.