The effect of epilepsy and anti-epileptic drugs on the anterior and posterior segment of the eye

Clinical relevance: Understanding the causes of visual symptoms in epilepsy patients is important for early diagnosis and taking precautions. Background: The aim of this study is to evaluate the anterior and posterior segment parameters in patients with generalized tonic-clonic epilepsy (GTCE). Methods: This retrospective study included 50 eyes of 50 patients with GTCE and 55 eyes of 55 healthy controls. For all participants, detailed ophthalmic examinations were obtained from the files of patients. Anterior segment parameters were measured using corneal topography and non-contact specular microscopy, and posterior segment parameters were measured using swept-source optical coherence tomography. Results: The mean age of the patients with GTCE was 43.3 +/- 13.2 years, and in the healthy controls it was 47.6 +/- 10.7 years (p = 0.405). In GTCE patients, 34 patients were treated with monotherapy (MT) and 16 patients with polytherapy (PT). Central macular thickness (CMT) was statistically significantly thin in GTCE patients (p = 0.001). The average and four quadrants (superior, inferior, nasal, temporal) retinal nerve fibre layer (RNFL) were thinner in GTCE patients than in the healthy controls, but there was no statistically significant difference (p > 0.05, all). The central corneal thickness was statistically significantly thin in GTCE patients (p = 0.04). Endothelial cell density (ECD), endothelial cell number (ECN), and average cell area (ACA) were statistically significantly lower in GTCE patients than in the healthy controls (p < 0.05, all). Although the CMT, average, and four-quadrants RNFL were thinner in the PT group compared to the MT group, no statistically significant difference was observed (p > 0.05, all). Total high-order aberrations (HOAs) were 0.6 +/- 0.4 in the MT group and 0.4 +/- 0.1 in the PT group (p = 0.01). ECD, ECN, and ACA measurements were observed to be lower in the PT group compared to the MT group, but no statistically significant difference was detected (p > 0.05, all). Conclusion: There could be statistically significant differences between GTCE patients and healthy controls in anterior and posterior segment parameters. This situation may be due to the epilepsy itself or to the antiepileptic drugs.