Topiramate Use Associated with Structural and Refractive Ocular Changes

The potent neurological medication topiramate (brand name Topamax) is used for various neurological and psychiatric conditions, including migraine, bipolar disorder and epilepsy. Despite its efficacy for these symptoms, the therapy has been linked to ocular complications, such as acute angle-closure glaucoma and changes in ophthalmic parameters like refractive status and intraocular pressure (IOP), among others. As topiramate use expands in clinical settings, more data are needed to understand its effects on patients’ ocular health. Seeing this gap led a group of researchers from India to look more closely at these parameters in patients who were newly initiated on topiramate. Their results were recently published in BMC Ophthalmology.  This was a prospective, non-randomized, longitudinal, comparative study conducted at a multi-specialty hospital in India, consisting of 160 eyes from 80 patients: 40 patients were in the topiramate study group and 40 healthy patients were in the control group, with mean ages of 30.3 and 30.7, respectively. Three patients in the study group were lost to follow-up. Women constituted the majority in both groups (87.5% in the topiramate group and 82.5% among controls). The most common indication for topiramate use was migraine (72.5%), followed by epilepsy (27.5%). The mean daily dose of topiramate was 56.2 ±16.6mg. A prospective comparative study of patients initiating topiramate therapy—commonly prescribed for migraine and epilepsy—found measurable ocular changes over three months, including increased intraocular pressure, thicker central corneas and lenses, a mild myopic shift and reduced anterior chamber depth. Investigators also observed changes in peripapillary retinal nerve fiber layer thickness. These graphs from the study show several key findings. Photo: Patro M, et al. BMC Ophthalmol. March 12, 2026. Click image to enlarge. The authors reported several significant results at the end of three months, including:A mean IOP increase from 13.46 ±1.71mm Hg at baseline to 18.18 ±2.48mm Hg.An increase in mean central corneal thickness (CCT) from 516.76μm ±34.58μm at baseline to 524.38μm ±36.04μm.Mean lens thickness (LT) went from 3.81mm at baseline to 3.85mm at the three-month endpoint. A myopic shift of -0.20D ±0.39D to -0.37D ±0.33D.A significant decrease in anterior chamber depth (ACD) from baseline (3.38mm to 3.35mm).Peripapillary retinal nerve fiber layer (RNFL) showed a statistically significant increase in average and all quadrants RNFL thickness over three months. According to the authors, these findings mirrored those of previous research. For instance, analyses have shown a sustained effect on CCT following topiramate use, and a significant change in LT as early as 15 days, supporting the hypothesis of choroidal effusion-induced lens thickening. In their paper, the authors referred to the work of Guier et al., who proposed that “topiramate causes suprachoroidal fluid accumulation, leading to zonular relaxation and lens thickening.” The myopic shift is likely “due to osmotic disturbances leading to increased lens thickness and choroidal expansion, as proposed by Gopalkrishna et al.,” wrote the authors.  The migraine diagnosis in particular may have influenced the significant thinning of peripapillary RNFL in the nasal and temporal quadrants, they wrote. “It is known that patients with migraine tend to have thinner peripapillary RNFL thickness as compared to healthy subjects. RNFL thickness exhibited a statistically significant increase across all quadrants over three months. [Others have] suggested that changes in RNFL thickness are due to the presence of carbonic anhydrase enzymes in retinal pigment epithelium and Müller cells, which increase the thickness of the internal limiting membrane of the retina.” Longer followups are needed to assess the sustained and cumulative effects of this drug on retinal structures. The short study period and small sample size are noted as potential limitations, as well as the unavailability of ultrasound biomicroscopy to assess anterior segment changes. “Baseline characteristics of the two groups might not be similar because the study group included migraine patients, which can independently be associated with thinner RNFL thickness,” they wrote. “This has the potential of acting as a confounding factor.” They concluded by emphasizing the importance of performing regular ocular exams in patients on topiramate to detect early ocular changes.Click here for the journal source. Patro M, Mishra S, Pattnaik S. et al. Ocular changes in patients on topiramate therapy: A hospital-based comparative study. BMC Ophthalmol. March 12, 2026. [Epub ahead of print.]  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.