Effects of Ranibizumab in Primary Pterygium Surgery

Overview

Pterygium is a common ocular surface disease in Malaysia. Without treatment, it can lead to severe visual impairment. Recurrence is the commonest complication and novel treatment approaches are crucial to prevent vision loss. The biological processes underlying the formation of pterygium are complex, but central to its pathogenesis is the angiogenic cytokine vascular endothelial growth factor (VEGF). VEGF is upregulated under conditions of increased oxidative stress, which plays an integral role in pterygium development (Cardenas-Cantu et al., 2016, Karaman, 2018, Norrby, 1998, Rossino et al., 2020, Shibunya, 2011).Various biomarkers on pterygium have been identified and are useful to determine the effectiveness of new modality treatment for pterygium. These markers can be identified via histopathological stain such as Masson Trichrome to observe changes of collagen fibres. Other identifiable markers include the use of special immunohistochemical stain such as anti CD34 antibody for microvascular density and anti-8-OHdG antibody for oxidative changes in the pterygium tissue. By analyzing the changes with or without Ranibizumab injection in addition to observation of clinical recurrence rate of pterygium, we are able to conclude the effectiveness of anti-VEGF on pterygium recurrence. The aim of the study was to evaluate the association between collagen fibres changes, microvascular density changes and inflammation resultant from oxidative stress with the clinical recurrence of pterygium following intralesional Ranibizumab injection in comparison to control group.

This is a prospective interventional study conducted from May 2018 to April 2020. Patients with primary pterygium who attended eye clinic Hospital Universiti Sains Malaysia (HUSM) Kubang Kerian, Kelantan and fulfilled the inclusion and exclusion criteria were recruited as participants of this study. Convenient sampling method was applied for participants' recruitment where all patients will be given thorough explanation in regards to the study and subsequently divided into interventional and control group. Intervention group participants were given intralesional Ranibizumab (0.5mg/ 0.05mL) 2 weeks prior to pterygium excision surgery. Both groups of participants undergo pterygium excision with autologous conjunctival graft surgery thereafter. Excised pterygium tissues were sent to the laboratory for slide preparation and staining with specific reagents including Masson Trichrome for collagen fibers, anti CD34 antibody for microvascular density and anti-8 OHdG antibody for oxidative stress changes. Slides were then analysed by the pathologist and statistical analysis of the results were carried out with the Statistical Package for the Social Sciences (SPSS) Version 26.0. All participants had intralesional Ranibizumab injection and pterygium excision with autologous conjunctival graft surgery in May 2018. They were scheduled for follow-up visits for the next 24 months to observe for complications of intralesional Ranibizumab injection, pterygium excision and conjunctival autograft surgery and any signs of recurrence.