Swedish Interactive Threshold Algorithm (SITA) Versus Standard Full Threshold Algorithm In Detecting Glaucomatous Visual Field Defects Using Humphrey Field Analyzer - A Descriptive Observational Study

Abstract

BACKGROUND Glaucoma is an ocular condition characterised by raised intraocular pressure, optic neuropathy and a corresponding visual field loss. This loss is usually very insidious and starts in the Bjerrum’s area and leaves the patients asymptomatic in the early stages. Having a sensitive and specific test to detect a subtle visual field loss is therefore very important in the management of glaucoma. OBJECTIVES 1. To find out the sensitivity and specificity of Swedish Interactive Threshold Algorithm (SITA) Standard with the Standard Full Threshold algorithm (FT) as gold standard in detecting visual field defects in primary open angle glaucoma patients using Humphrey Field Analyzer. 2. To compare the test time for SITA Standard and Standard Full Threshold algorithm in primary open angle glaucoma patients. METHODS This was a descriptive observational study in which 60 patients of primary open angle glaucoma who met the inclusion criteria were included. After obtaining written informed consent, all patients underwent visual field testing with both Standard Full Threshold Algorithm and SITA Standard algorithm using Humphrey Visual Field Analyzer II - i series perimeter. RESULTS The sensitivity of SITA standard in detecting glaucomatous visual field defects with Full Threshold algorithm as gold standard in primary open angle glaucoma patients was 95.24%.The specificity of SITA standard in detecting glaucomatous visual field defects was 94.44% with Full Threshold algorithm as gold XI standard. SITA Standard considerably reduced test taking time compared to Full Threshold by 45.84 % in glaucoma patients (p value < 0.0001). CONCLUSION The SITA Standard algorithm provides high enough sensitivity and specificity in detecting glaucomatous visual field defects with the Full Threshold algorithm as gold standard in primary open angle glaucoma patients with considerable savings in time.