Abstract
Objective: To establish morphological criteria for diagnosing clinical stages of pterygium using histological and immunohistochemical parameters and to evaluate pterygium as a possible manifestation of chronic ocular surface microtrauma associated with dry eye syndrome. Methods. A retrospective, multicentre, non-interventional study was conducted. The clinical and epidemiological analysis covered the period from January 28, 2019, to December 25, 2024. The main clinical cohort included 219 patients who underwent surgical treatment for pterygium in 2022–2023. Age, sex, lesion localisation, clinical stage, disease duration, and recurrence were analysed. Excised pterygium tissues were examined histologically using hematoxylin and eosin staining. Epithelial dysplasia, stromal elastosis, vascular density, and inflammatory infiltration were assessed. Immunohistochemical analysis was performed using Ki-67 as a marker of proliferative activity and vascular endothelial growth factor as a marker of angiogenesis. Data were processed using descriptive statistics and cross-tabulation. Results. The surgical conversion rate ranged from 0.53% in Astana to 6.67% in Semey. In one clinic in Astana, the number of pterygium surgeries increased by 284.2% in 2024 compared with 2019. Among 219 patients, men accounted for 51.6% and women for 48.4%. The mean patient age decreased by more than two years from 2022 to 2023. More than 94% of surgeries were performed at stages 2–3. Ki-67 expression increased from 2.1% at stage 1 to 55.8% at stage 4, while vascular endothelial growth factor expression increased from 10.5% to 92.7%. Conclusions. Clinical progression of pterygium was associated with increasing histological severity and higher expression of Ki-67 and vascular endothelial growth factor. The findings support the interpretation of pterygium as an active pathological process involving chronic microtrauma, inflammation, angiogenesis, and abnormal wound healing rather than a purely degenerative lesion.