Analysing ocular structural morbidities in younger adults using anti-seizure drugs: a cross-sectional study

The primary treatment for managing epilepsy consists of anti-seizure drugs (ASDs). Nevertheless, their prolonged use has been associated with various ocular complications. The structural alterations, such as thinning of the retinal nerve fiber layer (RNFL) and macular edema, have received limited research attention in younger adults undergoing extended ASD treatment.

This study aimed to evaluate the structural and functional changes in the eyes specifically, refractive error, tear film quality, macular health, and RNFL thickness among young adults who are on long-term ASD therapy.

A cross-sectional investigation involved 340 subjects aged between 20 and 40, comprising 200 ASD users and 140 healthy controls matched by age. All participant underwent a thorough ocular assessment that included best-corrected visual acuity (BCVA), subjective refraction, intraocular pressure, Schirmer's I & II tests, tear breakup time (TBUT), slit-lamp examination, fundus photography, and Optical Coherence Tomography (OCT) for analysis of the retinal nerve fibre layer (RNFL) and macula. The statistical evaluation was conducted using the Kruskal-Wallis H test, with significance established at P < 0.05.

Users of ASD exhibited a significantly higher average refractive error (-2.50DS/ ± 1.00DC) compared to controls (-0.75DS/ ± 0.75DC180). Tear metrics were considerably lower, with Schirmer's I & II and TBUT demonstrating significant disparities in sodium valproate users (P < 0.001). OCT findings indicated early signs of macular edema in 10% of ASD users, particularly among those on sodium valproate and topiramate. RNFL thickness displayed an average reduction of 8.5 µm relative to controls (P = 0.042), with the most pronounced thinning noted in users of lamotrigine and levetiracetam.

Prolonged ASD treatment is linked to observable changes in ocular structure, including dry eye disease, myopia, macular edema, and RNFL thinning. These outcomes highlight the necessity for routine ophthalmic evaluation and collaborative care to prevent irreversible visual impairment in individuals with epilepsy.