Abstract
Purpose :
Macular Corneal Dystrophy (MCD) is usually presented in the advanced form of the disease with a typical demonstration of the diffuse, stromal haze and gray-white opacities involving the entire corneal stroma from limbus to limbus. Therefore, the diagnosis of dystrophy in the early stages could be challenging.
The purpose is to evaluate early abnormalities including anterior and posterior corneal topography, elevation maps, Fourier indices (FI), ectasia screening index (ESI), and thickness profile of the cornea in MCD compared with normal subjects using the 1310 nm anterior eye segment swept-source optical coherence tomography (SS-OCT)
Methods :
The prospective, controlled, observational study was conducted in accordance with the ethical standards of the Declaration of Helsinki and was approved by the Ethics Committee. 18 eyes of 12 patients diagnosed clinically (confocal microscopy) and genetically (CHST6 gene screening) with MCD (SG) and 70 eyes of 70 normal subjects (CG) were included in the study (mean age was: SG 32,3 ± 9,63 y; CG 26,65 ± 5,62). The groups were gender and age-matched.
A series of anterior and posterior corneal shape and thickness parameters were studied, as well as keratometric and posterior 3 and 6 mm FI (spherical, regular, asymmetry, and higher-order); anterior and posterior ESI and anterior chamber depth (ACD). Also, elevation maps were evaluated compared to the theoretical nomogram.
Results :
Keratometric astigmatism revealed a significant difference (p<.001). There was a high degree of mirror symmetry in shape between the right and left corneas based on elevation maps in normal eyes. In MCD eyes there was no elevation mirror symmetry with the greatest degree of irregularity. There was also a significant difference in 3 and 6 mm FI, as well as in the corneal thickness. FI analysis revealed abnormalities regarding three parameters: regular astigmatism, higher order (anterior and posterior), and asymmetry (anterior). Significant corneal thinning was present in MCD.
Conclusions :
The information on corneal elevation mirror symmetry obtained with SS-OCT from normal eyes provides reference data for comparison with diseased corneas. Corneal thinning is the main well-known feature of MCD, but the significant change in other parameters – anterior astigmatism, elevation maps and FI should be taken into consideration in the disease pathogenesis.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.