Visual Field defect detection with II and III stimuli in pre-perimetric glaucoma patients

• Grant number: 25/02060-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Mário Luiz Ribeiro Monteiro
• Grantee: Amanda Latuffe Soares Damião
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

1. ABSTRACT1.1) Introduction: Glaucoma is a progressive optic neuropathy and the leading cause of irreversible blindness worldwide. Functional tests, such as computerized perimetry, are considered the gold standard for the diagnosis and monitoring of glaucoma. However, perimetric changes in glaucoma typically occur after significant loss of optic nerve axons. The detection and quantification of functional loss is important for the diagnosis, staging, prognosis, and follow-up of the disease. The correlation between structural and functional defects is crucial in glaucoma diagnosis. Structural exams often detect glaucomatous damage in the early stages of the disease, before changes appear in conventional perimetry. When this happens, these glaucomas are referred to as pre-perimetric. It is possible that perimetric changes may only occur after a significant loss of axons, partly due to the stimulus used in conventional perimetry. The size of this light stimulus (LS), due to its dimensions, can activate a sufficient number of neurons to detect it, thus potentially masking any nerve loss and resulting in a normal test. Smaller light stimuli have been shown to be more sensitive in detecting early glaucomatous defects, but they may lead to a higher number of false positives and non-reproducible tests. 1.2) Objectives: The objective of this study is to investigate whether a smaller light stimulus than the one conventionally used is capable of detecting functional changes in pre-perimetric glaucoma. 1.3) Materials and Methods: This will be a cross-sectional cohort study involving 30 eyes with glaucomatous neuropathy but no visual field (VF) loss in the standard SITA 24-2 Humphrey automated perimetry, and 30 healthy eyes. The participants will undergo a complete ophthalmologic exam, including 10-2 and 24-2 visual field tests using the Humphrey perimeter. Visual field tests will be performed with Fixation Targets II and III, with rest intervals between tests. The central and peripheral visual field results of the patients and controls will be compared.