From the Guidelines
Viagra (sildenafil) can cause visual side effects, including blue-tinted vision, increased light sensitivity, blurred vision, and changes in color perception, with a potential increased risk of non-arteritic anterior ischemic optic neuropathy (NAION) as reported in very-low-quality evidence 1. The most common adverse effects of sildenafil are headache, flushing, rhinitis, and dyspepsia, while less common adverse effects include visual disturbances, myalgia, nausea, diarrhea, vomiting, dizziness, and chest pain 1. Some key points to consider:
- High-quality evidence showed that men receiving PDE-5 inhibitors are more likely to have at least 1 adverse event compared with placebo recipients, but the incidence for more serious adverse events was less than 2%, with no difference between PDE-5 inhibitors and placebo 1.
- Very-low-quality evidence evaluating the association of NAION with the use of PDE-5 inhibitors showed that among 4 million veterans aged 50 years or older, PDE-5 inhibitors were not associated with an increased risk for NAION, but were associated with an increased risk for possible NAION 1.
- Patients with pre-existing eye conditions, cardiovascular disease, or those taking nitrates should be particularly cautious when taking Viagra, and anyone experiencing persistent visual changes lasting more than a few hours after taking Viagra should seek immediate medical attention 1. Key considerations for clinicians:
- The potential benefits of sildenafil for treating erectile dysfunction must be weighed against the potential risks, including visual side effects.
- Patients should be counseled on the potential risks and benefits of sildenafil and monitored for any adverse effects.
- In cases where patients experience persistent or severe visual disturbances, alternative treatments for erectile dysfunction should be considered.
From the FDA Drug Label
When used to treat erectile dysfunction, non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported postmarketing in temporal association with the use of phosphodiesterase type 5 (PDE-5) inhibitors, including sildenafil Most, but not all, of these patients had underlying anatomic or vascular risk factors for developing NAION, including but not necessarily limited to: low cup to disc ratio ("crowded disc"), age over 50, diabetes, hypertension, coronary artery disease, hyperlipidemia and smoking It is not possible to determine whether these events are related directly to the use of PDE-5 inhibitors, to the patient's underlying vascular risk factors or anatomical defects, to a combination of these factors, or to other factors There are no controlled clinical data on the safety or efficacy of sildenafil citrate in patients with retinitis pigmentosa, a minority whom have genetic disorders of retinal phosphodiesterases. Visual disturbances were identified as mild and transient, and were predominately color-tinge to vision, but also increased sensitivity to light or blurred vision.
The potential visual side effects of Viagra (sildenafil) include:
- Non-arteritic anterior ischemic optic neuropathy (NAION), which can cause decreased vision or permanent loss of vision
- Visual disturbances, such as:
- Color-tinge to vision
- Increased sensitivity to light
- Blurred vision
- Retinal hemorrhage
- Eye hemorrhage
It is essential to note that these events may be related to the use of PDE-5 inhibitors, underlying vascular risk factors, anatomical defects, or a combination of these factors. Patients should be advised to seek immediate medical attention if they experience a sudden loss of vision in one or both eyes while taking sildenafil 2.
From the Research
Visual Side Effects of Viagra
The potential visual side effects of Viagra (sildenafil) include:
- Changes in color vision and light perception
- Blurred vision
- Photophobia
- Conjunctival hyperemia and keratitis
- Alterations in the electroretinogram (ERG) 3
- Reversible increase in intraocular pressure (IOP)
- Nonarteritic anterior ischemic optic neuropathy (NAION) 4, 3, 5, 6
- Reversible idiopathic serous macular detachment
- Central serous retinopathy
- ERG disturbances
Risk Factors and Precautions
Certain individuals may be at increased risk of developing visual side effects, including:
- Those with a history of NAION in one eye 6
- Those with vascular risk factors, such as hypertension, diabetes, and hypercholesterolemia 7, 6
- Those taking higher doses of sildenafil 3, 7 Patients should be warned about the potential visual side effects and advised to seek medical attention if they experience any changes in vision or visual field loss after using sildenafil 3, 6.
Mechanism of Action
Sildenafil's mechanism of action involves the inhibition of phosphodiesterase type 5 (PDE5), which leads to increased levels of cyclic guanosine monophosphate (cGMP) and subsequent vasodilation 3, 7. Sildenafil also has a weaker inhibitory action on PDE6, which is present in the rod and cone photoreceptors, and this may contribute to its visual side effects 3, 7.