Abstract
Purpose: :
To evaluate retinal fixation stability, obtained by microperimetry, both in static and dynamic patterns, in normal and pathologic eyes.
Methods: :
One hundred and thirty-one pathologic eyes (38 diabetic retinopathy, 35 age-related macular degeneration (AMD), 37 glaucoma and 21 vitreo-retinal interface disorders) and 152 aged-matched normal eyes were included in this study. Retinal fixation characteristic (stability) was studied during a pure fixation task (static fixation; 60 seconds) and during a differential light threshold quantification (dynamic fixation) by MP-1 microperimeter (Nidek, Gamagori, Japan). Fixation stability was quantified with both the automatic clinical score (central 2° and central 4°) and the automatic calculation of the bivariate contour ellipse area results (BCEA).
Results: :
Using MP1 automatic clinical score of fixation stability in both static and dynamic condition, pathologic group was statistically different to normal group (p<0.0001). There was not significant difference between static and dynamic retinal fixation in normal group whereas in pathologic group the difference between static and dynamic retinal fixation was statistically significant (p<0.0001). Analyzing BCEA the difference between pathologic and control groups was statistically significant both in static and in dynamic retinal fixation (p<0.001). The difference between static and dynamic fixation is statistically significant both in normal and in pathologic eyes (p<0.0001). Fixation stability is related with both techniques, to the etiology of macular disorders (static, p<0.0001; dynamic, p<0.001).
Conclusions: :
Fixation stability may be characterized, using microperimetry, by static and dynamic patterns. BCEA can be useful for monitoring minimal quantitative changes of the fixation area, related to the standard clinical score. Fixation stability remains the most important clinical parameter of retinal fixation in macular disorders.
Keywords: perimetry • age-related macular degeneration • diabetic retinopathy