Pterygium Extension Rate May Predict Postoperative Recovery Potential

The pterygium extension rate is a metric used to gauge how far pterygium has progressed across the cornea. This image from the study shows how to calculate it: line A represents the distance from the nasal limbus to the pterygium apex and line B represents the horizontal corneal diameter measured on the same image. Photo: Miyakoshi A, et al. BMC Ophthalmol. June 11, 2026. Click image to enlarge. A recent study published in BMC Ophthalmology reported that a simple preoperative pterygium extension rate, formulated by the authors, could predict which eyes were more and less likely to regain normal corneal functioning after pterygium excision.Researchers evaluated whether a straightforward measurement from slit lamp photographs could help practitioners determine the longest time period at which pterygium surgery could be delayed without reducing the likelihood of postoperative optical recovery. The authors reported that, to carry out this evaluation, they retrospectively reviewed 134 eyes from 134 patients with primary pterygium who underwent surgical excision and completed at least one month of follow-up. The patients had a mean age of 64.8 years and 70.9% were male.The researchers explained in the study that they calculated the pterygium extension rate by dividing “the ratio of the distance from the nasal limbus to the pterygium apex” by “the horizontal corneal diameter.” Before surgery and one month after it, they also measured corneal asymmetry and higher-order irregularity (HOI) within the central 3mm corneal zone using swept-source anterior segment OCT.Higher pterygium extension rates were found to be associated with greater corneal asymmetry and greater HOI. In addition, surgery significantly improved the results for every patients’ corneas and reduced astigmatism, asymmetry and HOI, while endothelial cell density remained stable.Further analysis identified the specific thresholds of the extension rate during postoperative recovery. The researchers explained in the study that “the optimal cutoff value for predicting postoperative asymmetry >0.52 D was 0.359,” whereas “the optimal cutoff value for predicting postoperative HOI >0.20D was 0.292.” Postoperative normalization occurred in 62.7% of eyes for asymmetry and 38.1% for HOI.Limitations included the retrospective, single-center study design, which may have perpetuated “selection bias and limit generalizability,” and “variations in photographic angle or ocular alignment,” which could have caused errors in the measurement data, the paper explained.The authors concluded that the pterygium extension rate provided a practical, widely accessible metric that could help estimate how long to potentially delay surgery while still allowing the possibility of postoperative optical recovery. They noted that the measurement required only routine slit-lamp photographs rather than specialized imaging equipment, making it a potentially useful tool for surgical timing and patient counseling.Click here for the journal source. Miyakoshi A, Toyoda N, Katayama H, et al. Preoperative pterygium extension rate predicts postoperative corneal optical recovery after pterygium excision. BMC Ophthalmol. June 11, 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.