Abstract
Purpose :
OCT imaging has been recently used to measure eccentric fixation(EF) in subjects with amblyopia. Meanwhile, preferential retinal loci (PRL) and fixation stability can be measured using microperimetry. We hypothesized that the fixation features obtained by OCT and microperimetry will be correlated. This prospective study was to compare the fixation features obtained by these two methods and to elaborate their correlation with visual acuity(VA) in children with amblyopia.
Methods :
Two group of children between the age of 7-14 years of age (5 amblyopic subjects and 6 controls) were recruited. Spectral-domain OCT macular scan images were used to estimate eccentric fixation. The OCT eccentric fixation (OCT-EF) was defined as the distance between fovea center to the fixation point. The measurement was converted to degrees after adjusting with axial length(AL) measured with IOLMaster. Microperimeter (NIDEK MP3) was used to measure 30 seconds of fixation stability and the built-in software calculated PRL and bivariate contour ellipse area (BCEA). OCT-EF, logBCEA (68.4%/95.4%/99.6%), and PRL of the amblyopic eye(AE), the fellow eye(FE), and the right eye of controls were compared. Each measurement’s correlation to VA was assessed.
Results :
The mean LogMAR VA was 0.40 ±0.09 (mean±SD) in the AE, -0.02 ±0.10 in the FE, and -0.1± 0.04 in the controls(P<0.001).The mean OCT-EF in degree was 0.21±0.31 in the controls, and 1.55±1.14 and 0.83±0.33 in AE and FE respectively, where the OCT-EF of the AE was significantly higher than the controls(P=0.042). The OCT-EF in FE is higher than the control eyes(P=0.01). The mean logBCEA(68.4%) in AE (0.53±0.38 deg) was significantly larger than in FE (-0.07±0.29 deg, P<0.01). LogBCEA was positively correlated to the VA(r=0.76, P<0.01). Correlation between OCT-EF and logBCEA was not significant(r = 0.17, P= 0.33). The direction of OCT-EF was nasal in 70% of the eyes; the direction of EF from microperimeter were nasal in 78% eyes; and 67% of them were in agreement.
Conclusions :
Fixation instability and OCT-EF were frequently seen in amblyopia. This pilot study showed that fixation instability is associated with VA loss in the amblyopic eye. EF direction from two methods were often nasal and in agreement. Further investigation with more subjects is required to draw a firm conclusion.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.