Standard Automated Perimetry and Short-Wavelength Automated Perimetry Performed With Swedish Interactive Threshold Algorithm in Glaucoma Suspects Detected With Confocal Laser Polarimetry and Confocal Laser Tomography

Abstract

Purpose: : to compare the ability of Standard Automated Perimetry (SAP) and Short-Wavelength (SWAP) with Swedish Interactive Threshold Algorithm (SITA) to point out early functional defects in glaucoma suspects picked up using confocal laser polarimetry (GDx-VCC) and confocal laser tomography (HRT-III)

Methods: : randomly selected 90 eyes of 90 patients screened by the glaucoma unit of the University Eye Clinic of Pavia (Italy) on the basis of clinical suspicion of having early glaucoma, were submitted to a complete ophthalmic examination and to confocal laser polarimetry and tomography. Moorfields regression analysis (MRA), cup shape measure (CSM), rim area (RA) for HRT-III and nerve fiber indicator (NFI), superior and inferior TSNIT average for GDx-VCC were taken into account. If at least one of the morphometric parameter was found out of the normal limits compared to the normative database of each instrument, a 24-2 Humphrey 750 SAP and SWAP tests were performed using the SITA algorithm in both cases. Mean defect (MD), pattern standard deviation (PSD), number of points significantly depressed < 5% and < 1% in the pattern deviation plot and test duration for SITA-SAP and SITA-SWAP were compared using the Wilcoxon signed rank test. Media opacities > 1 according to the lens Opacities Classification System (LOCS) III were excluded

Results: : SWAP gave a significantly larger MD and PSD defect than SAP (p<0.01). This was confirmed by a larger number of depressed points in the pattern deviation plot with SWAP than with SAP, but only the number of points with p < 1% was significantly different (p< 0.01). The SWAP test duration was significantly shorter than SAP

Conclusions: : SITA-SWAP can provide a useful identification of diffuse and focal functional loss in a shorter test time than SITA-SAP. The SITA applied to SWAP can improve the ability of the perimetric test to pick up early defects involving short-wavelength sensitive ganglion cells in cases of suspect early glaucoma damage using imaging techniques

Keywords: visual fields • optic nerve • imaging/image analysis: clinical