Abstract
Purpose :
To fit conical functions to peripheral biometric (axial length, AL) and optical quality (aberrations) data and analyze their correlations in young adults with emmetropia or myopia.
Methods :
Central and peripheral AL (Lenstar LS900, Haag Streit) and monochromatic aberrations (scanning peripheral aberrometer, VopticaSL) were obtained in n=23 subjects with myopia (mean central SE: -3.13±1.70 D, central AL: 24.48±0.73mm, logMAR DVA: 0.0±0.0, age: 24.04±1.43 years) and n=12 subjects with emmetropia (mean central SE: 0.00±0.23 D, central AL: 23.45±0.64mm, logMAR DVA: 0.0±0.0, age: 24.17±1.90 years). AL measurements were taken at 13 eccentricities across the central 60 degrees of the ocular horizontal meridian. A conic function was used to fit retinal contours obtained from AL raw values, as described by Verkicharla et al, 2015 (yr=AL’p–rcvsinθ and Δz3=rcv/(1–cosθ)+AL’pcosθ–AL’a). Aberrations measurements were taken for every degree across 60 degrees of the ocular horizontal meridian while subjects looked at 4m without correction. Optical quality was defined as the RMS (Root Mean Square) for each eye computed up to the 5th order for a 4mm pupil. RMS profiles were correlated with AL and also fitted using conic functions. Two-sample t-tests and regression analysis were applied to biometric and optical quality retinal contour metrics.
Results :
There was no correlation of AL in the goodness of fit (r2) (p=0.81), curvature (p=0.60), or asphericity (p=0.65) of the retinal contour fittings using the biometric parameters and within the range of AL used in this study.There was also no effect of refractive group in the r2 (t=2.06; p=0.57), curvature (t=2.20; p=0.34), or asphericity (t=2.07; p=0.48). The retinal contour fittings using the optical metrics showed no effect of refractive group (p>0.5). The largest peripheral monochromatic aberrations are M, J0 and J45. Parameter RMSall and M best correlates with AL within 8deg eccentricity (r>0.6, p<0.05), whereas J0 best correlates with AL within the central 8deg (r=0.56-0.60, p<0.05).
Conclusions :
Biometric and optical quality data across the retina may be accurately fitted to conic functions to evaluate retinal contours in emmetropia and myopia. Fitting conic functions to the RMS values across the retina simplifies the use of peripheral optical quality data and may be used in future studies as a peripheral optical quality metric.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.