Abstract
Purpose:
The aim of this study was to investigate a new computer-assisted image processing technique for quantitative analysis of the impact of pterygia on refractive indices and ocular higher-order aberrations (HOAs) and its comparison with other conventional techniques for the measurement of pterygium size.
Methods:
A total of twenty-one pterygia of 17 patients were included in the study. All pterygia were measured by three different methods, including slit-lamp beam, a surgical compass and a new computer-assisted image processing method. Refractive indices and HOAs were analyzed in all cases.
Results:
The new system revealed excellent intraclass correlation coefficients for intra- and interobserver reliability (1.00 and 0.99, respectively). While horizontal and vertical length measured with slit-lamp beam and a surgical-compass were slightly correlated with some of the HOAs, a digital pterygium/cornea ratio analyzed with the new image-processing system was strongly correlated with total (rho: 0.62, p= 0.003) and HOAs (rho: 0.60, p= 0.004) including total coma (rho: 0.67, p= 0.001), trefoil (rho: 0.54, p= 0.011), tetrafoil (rho: 0.66, p= 0.001), HO astigmatism (rho: 0.68, p= 0.001).
Conclusions:
Digital pterygium/cornea ratio analyzed by the new computer-assisted image processing system provides an objective and reliable method for evaluating the impact of pterygium size on refractive indices and HOAs.
Keywords: 665 pterygium •
550 imaging/image analysis: clinical •
549 image processing