Vigabatrin-induced peripheral visual field defects in patients with refractory partial epilepsy

Area of Science:

• Ophthalmology
• Neurology
• Clinical Trials

Background:

• Vigabatrin is an antiepileptic drug known to cause retinopathy.
• Previous studies on vigabatrin-induced visual field constriction relied on subjective perimetry interpretations.
• Objective quantitative methods are needed to confirm vigabatrin's ocular side effects.

Purpose of the Study:

• To quantitatively assess vigabatrin-induced visual field constriction using Goldmann kinetic perimetry.
• To validate previous findings on visual field defects in patients with refractory partial epilepsy.
• To correlate visual field constriction severity with patient-reported symptoms.

Main Methods:

• A subset of 735 patients from a prospective, observational study was analyzed.
• Patients aged ≥ 8 years with refractory partial epilepsy were grouped based on vigabatrin exposure.
• Goldmann kinetic perimetry measured temporal and nasal visual fields using specific isopters (V4e, IV4e, I2e, I1e).

Main Results:

• Of 258 vigabatrin-exposed patients with Goldmann perimetry data, 16% had moderate visual field defects (30-60° retained temporal vision).
• 3% of vigabatrin-exposed patients exhibited severe visual field defects (< 30° retained temporal vision).
• Visual function questionnaire data showed a weak correlation between defect severity and reported visual symptoms.

Conclusions:

• The findings quantitatively confirm vigabatrin-associated visual field constriction.
• Visual field constriction, when present, is predominantly mild to moderate and asymptomatic.
• Individual benefit-risk analysis remains crucial for prescribing vigabatrin.