Long-term PGA Use Affects Corneal Biomechanics in POAG, Study Reports

Compared to healthy controls, POAG patients on prostaglandin analogs had shorter second applanation deflection length, smaller second applanation deflection area and a higher deformation amplitude ratio max 1mm. Conversely, other IOP-lowering meds and prior SLT treatment appeared to have no relevant influence on corneal biomechanics. Photo: Andrew Rixon, OD. Click image to enlarge. Researchers recently set out to determine whether chronic topical intraocular pressure (IOP)-lowering treatment affects corneal biomechanical properties in patients with primary open-angle glaucoma (POAG). They performed a cross-sectional comparative study, which concluded that prostaglandin analog (PGA) use was associated with measurable changes in selected dynamic corneal response parameters, which may influence IOP interpretation and glaucoma risk assessment. In contrast, other glaucoma medications showed little to no meaningful effect. The study, published recently in the journal Cornea, included 225 white European patients with POAG and 78 healthy control subjects matched for age, central corneal thickness (CCT) and IOP. The glaucoma cohort had a mean age of 70.3 years and included 154 patients with high-pressure glaucoma and 71 with normal-pressure glaucoma. Disease duration averaged 15 ± 12 years, and 95.6% of patients used pressure-lowering drops, with an average of 3.5 medications per patient. More than half of glaucoma patients had previously undergone laser surgery, most commonly selective laser trabeculoplasty.Compared with healthy subjects, patients with POAG showed significant differences in several biomechanical measures. Namely, patients on PGAs had shorter second applanation deflection length (2.89mm vs. 3.23mm), smaller second applanation deflection area (0.24mm² vs. 0.28mm²) and a higher deformation amplitude ratio max 1mm (1.67 vs. 1.55). In contrast, beta-blockers, carbonic anhydrase inhibitors, alpha agonists and miotics produced only minor changes in corneal biomechanics, and previous laser treatment appeared to have no effect. “It is necessary to speculate on the mechanisms by which prostaglandins might alter corneal biomechanics,” the authors stated in their paper on the findings. They noted that PGA treatment has been shown to reduce corneal thickness, a metric that is known to influence dynamic corneal response measurements. “At the same time,” the authors wrote, “CCT reduction in glaucoma is known, and a CCT-lowering effect of PGA is suspected,” with most studies showing that topical PGA application results in a reduction in CCT. This study has several limitations, one being its cross-sectional design. The authors also disclose that their analysis didn’t distinguish between preserved and preservative-free formulations, nor did it compare corneal changes across different PGA types. Given that long-term topical PGA application may confer detectable changes in corneal biomechanics in POAG patients, the researchers cautioned, “Combined with the known influence on corneal thickness, there might be a risk of underestimating IOP or overestimating the effect of PGA treatment itself.” These results, they concluded, not only improve understanding of the disease mechanisms underlying glaucoma-related corneal changes but “may also help to adjust biomechanical readings to increase their applicability in everyday clinical practice, for example in keratoconus, refractive patients or [those with diabetes].”Click here for the journal source. Ramm L, Fleischer W, Khoramnia R, et al. Influence of topical medication on corneal biomechanics in primary open-angle glaucoma. Cornea. 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.