Abstract
Purpose::
To evaluate the role of microperimetry in eyes with advanced glaucoma.
Methods::
Twenty eyes of twenty patients affected by advanced glaucoma underwent central and peripapillary fundus-related differential light threshold quantification with microperimetry (MP1 Microperimeter, Nidek Technologies, Padova, Italy). Fixation characteristics (location and stability) were documented. White-on-white standard visual field defects quantification with Swedish Interactive Thresholding Algorithm Standard 24-2 perimetry (Carl Zeiss Meditec Inc., USA) was also perforrmed. Automatic microperimetry follow-up (testing exactly the same retinal points independently from fixation shifts) was performed 3 and 6 months after baseline examination.
Results::
At baseline, significant correlation (r=0.71) was found between central mean sensitivity loss quantified with microperimetry versus conventional white-on-white perimetry. Peripapillary microperimetry differential light threshold was circumferentially depressed (0.0 ± 5 dB), with absolute scotoma in upper and lower poles in all eyes. Moreover, central microperimetry exactly documented residual functional retinal areas (> 0dB), which were undetected by conventional perimetry, with significant correlation (r=0.85) with peripapillary residual sensitivity. Fixation was unstable in 18/20 eyes (90%). During follow-up. microperimetry showed progression of visual field damage, undetected by standard perimetry (p< 0.001)
Conclusions::
Microperimetry is able to exactly document residual visual field areas in advanced glaucoma. Fixation instability prevents accurate localization of the same areas with standard perimetry. Automatic microperimetry follow-up may accurately monitor the functional impact of any therapeutic approach in advanced glaucoma.
Keywords: perimetry • visual fields