Purchase this article with an account.
Izabela Katarzyna Garaszczuk, Maryam Mousavi, Alejandro Cervino Exposito, Dorota Helena Szczesna-Iskander, Robert Iskander, Danilo Andrade de Jesus; Scleral radius estimation based on anterior eye surface. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1125.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To precisely estimate scleral radius based on spherical approximation using scleral topography.
Eye Surface Profiler (ESP, Eaglet-Eye, Netherlands) was used to acquire the anterior eye surface. Twenty-three emmetropic subjects aged 28.1 ± 6.6 years (range from 20 to 45) volunteered for the study. For comparison purposes, a low myopic (-2.0 D) and a high myopic (-6.5D) subjects were measured. Scleral radius was obtained based on the approximation of the topographical scleral data to a sphere using least squares fitting. The spherical approximation with and without the axial length as a reference point was compared. Moreover, the influence of the eye palpebral aperture was studied. Lastly, measurements of corneal radius, central corneal thickness, anterior chamber depth and white-to-white corneal diameter were acquired with IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany) and compared to the scleral radius.
The spherical approximation has shown to be highly precise for emmetropic eyes, however, its error has revealed to be proportional to the myopic refraction error. The estimated scleral radius for the emmetropic group considering the axial length and a normal palpebral aperture was 11.2 ± 0.3 mm. The obtained values have shown to be highly precise with a coefficient of variation of 0.4%. Results have shown that Scleral radius can be estimated precisely considering only the anterior surface data if full measurement of scleral region, including inferior and superior parts of sclera, is acquired. A statistically significant correlation between axial length and scleral radius (R2 = 0.957, p<0.001) was observed. Moreover, corneal radius (R2 = 0.420, p<0.001), anterior chamber depth (R2 =0.141, p=0.039) and white-to-white corneal diameter (R2 = 0.146, p=0.036) have also shown statistically significant correlations with the scleral radius. Lastly, no correlation was observed comparing scleral radius to the central corneal thickness (R2 = 0.047, p=0.161).
Three-dimensional topographical data of an emmetropic eye acquired with ESP, can be used to calculate the scleral radius with high precision based on a spherical approximation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only