Can enclomiphene (clomiphene) citrate cause blurry vision in patients, particularly those with a history of eye diseases or other underlying medical conditions?

Can Enclomiphene Citrate Cause Blurry Vision?

Yes, enclomiphene (clomiphene) citrate definitively causes blurry vision and other visual disturbances as a documented adverse effect, and patients must be warned about this risk before starting therapy. 1

Mechanism and Incidence of Visual Disturbances

Blurring and other visual symptoms such as spots or flashes (scintillating scotomata) may occasionally occur during clomiphene citrate therapy, with incidence increasing with higher total dose or longer therapy duration. 1 The visual symptoms appear to be due to intensification and prolongation of after-images, and often first appear or are accentuated with exposure to brightly lit environments. 1

The specific visual disturbances reported include:

• Blurred vision 1, 2
• Scintillating scotomata (spots or flashes) 1
• Prolonged afterimages (palinopsia) 3
• Shimmering of the peripheral visual field 3
• Photophobia 3

Reversibility and Risk of Permanent Damage

While visual disturbances are usually reversible upon discontinuation, cases of prolonged and potentially irreversible visual disturbance have been reported, especially with increased dosage or duration of therapy. 1 This represents a critical clinical concern that must be communicated to patients.

• In one observational study of 8 women, the effect of clomiphene citrate on vision was minimal with bilateral reduction in flicker sensitivity being the only observed disturbance, and visual symptoms were reversible in all patients. 4
• However, three patients treated for 4 to 15 months experienced prolonged afterimages, shimmering peripheral fields, and photophobia that did not resolve on cessation of treatment and remained symptomatic for 2 to 7 years after discontinuing the medication. 3
• One study patient taking 200 mg daily developed visual blurring on day 7 that progressed to severe diminution of visual acuity by day 10, though this returned to normal 3 days after stopping treatment. 1

Critical Safety Warnings and Patient Counseling

Patients must be warned that visual symptoms may render activities such as driving a car or operating machinery more hazardous than usual, particularly under conditions of variable lighting. 1

Any patient who develops visual symptoms should discontinue treatment immediately and have a complete ophthalmological evaluation carried out promptly. 1 This is non-negotiable given the risk of irreversible changes with continued administration. 3

Before prescribing clomiphene citrate:

• Inform patients about the risk of visual disturbances including blurred vision, spots, flashes, and photophobia 1
• Warn about increased hazard with driving and operating machinery 1
• Instruct patients to report any visual symptoms immediately 5
• Advise that continued administration after symptom onset may cause irreversible changes 3

Clinical Monitoring Approach

For patients experiencing visual symptoms:

1. Stop clomiphene citrate immediately 1, 5
2. Perform comprehensive ophthalmological evaluation including:
   • Visual acuity testing 1
   • Assessment for scotomata 1
   • Retinal cell function testing (electroretinography) if indicated 1
   • Evaluation for phosphenes 1

• Women who experience visual symptoms can usually be monitored and therapy maintained if symptoms are mild and reversible 4, though this must be weighed against the risk of permanent damage 3
• In a long-term safety study of 400 patients treated for up to 84 months, only 3% reported blurred vision as a side effect 2, suggesting the complication is relatively uncommon but clinically significant when it occurs

Special Considerations

The visual disturbances are dose-dependent, with higher doses and longer duration increasing risk. 1 Ophthalmologically definable scotomata and electroretinographic changes have been documented. 1 While measured visual acuity usually remains unaffected, severe cases of visual impairment can occur. 1

Patients with characteristic visual symptoms should be questioned about past use of clomiphene, as the association may not be immediately recognized. 3