Abstract
Purpose: :
To investigate the relationship between retinal sensitivity by SLO Microperimetry (SLO-MP) and Humphrey Visual Field (HVF) to retinal nerve fiber layer (RNFL) thickness by SLO-Ocular Coherence Tomography (SLO-OCT) in patients with central visual field loss in advanced glaucoma.
Methods: :
36 eyes of 25 patients with advanced glaucoma and scotomas involving the central 10° on two consecutive Humphrey (Zeiss Medetec) 10-2 full threshold (H10) visual field tests were included. A modified 10-5 SLO-MP (OCT-SLOTM Ophthalmic Technologies Inc) was performed within three months of the last reliable H10 using a Goldman size III 200msec stimulus presented at 1-second interval with real time monitoring of fixation. SLO-OCT was used to detect the mean RNFL thickness within a superimposed standard CSME grid (diameter =3.5mm). Likewise, the CSME grid was superimposed on the SLO-MP and H10 raw scale data for comparison. For each test, retinal sensitivity at the macula was calculated as the mean db level within the grid. Linear regression analysis was performed to compare HVF and SLO-MP retinal sensitivity to mean RNFL thickness within the macular region.
Results: :
Macular sensitivity was comparably reduced but with much greater loss seen in SLO-MP (9.33 ± 3.37dB) when compared to H10 (18.83 ± 6.46 dB, p <0.0001). Mean RNFL thickness within the macular region was found to correlate significantly with retinal sensitivity as determined by both SLO-MP (r=0.39, p<0.02) and HVF (r=0.37, p<0.03).
Conclusions: :
SLO-MP correlates well with H10 for overall evaluation of central visual field loss in patients with advanced glaucoma. Furthermore, retinal sensitivity determined by HVF and SLO-MP within the macular area correlates significantly with mean RNFL thickness measured by OCT-SLO. A larger sample size is needed to further study and better understand the value of this diagnostic tool.
Keywords: perimetry • visual fields • clinical (human) or epidemiologic studies: systems/equipment/techniques