Abstract
Purpose: :
To compare standard achromatic perimetry (SAP), short wavelength automated perimetry (SWAP), transient pattern electroretinogram (PERG–t) and steady–state pattern electroretinogram (PERG–ss) in the detection of early glaucoma.
Methods: :
The participants consisted of 38 normal subjects and 38 patients with early primary open angle glaucoma (POAG). The diagnosis of early POAG required glaucomatous concentric optic disc cupping with a cup–to–disc ratio of 0.7 or greater, or focal glaucomatous cupping, with a visual field loss lower than –3 dB in the global index mean deviation (MD) on SAP and untreated IOP of more than 22 mmHg. SAP and SWAP was performed using the Humphrey Field Analyser II 750 (Humprey Systems Inc, Dublin, CA) using full–threshold 24–2 program. PERG–t and PERG–ss was performed using the EPIC 2000 system (LKC Technologies Inc, Gaithersburg, MD) following the standard for PERG of the International Society for Clinical Electrophysiology of Vision (ISCEV). All participants underwent full ophthtalmologic clinical assessment and SAP, SWAP, PERG–t and PERG–ss. Only patients with a minimum best–corrected visual acuity of 20/25 or better and clear media were selected. Statistical package for social sciences (SPSS Inc., Chicago, IL) was used for statistical analysis.
Results: :
The results of the early POAG group were: SAP with sensitivity of 73.7% and specificity of 89.5%, SWAP with sensitivity of 92.1% and specificity of 71.1%, PERG–t amplitude P1N2 with sensitivity of 83.3% and specificity of 80.0% and PERG–ss amplitude calculated by fast fourier transform with sensitivity of 88.5% and specificity of 85.0%.
Conclusions: :
SAP, SWAP, PERG–t and PERG–ss were observed as useful tools in the early diagnosis of glaucoma. The PERG–ss presented the best results regarding sensitivity–specificity in the early diagnosis of glaucomatous damage.
Keywords: electrophysiology: clinical • perimetry • color vision