Abstract
Abstract: :
Purpose: To map corneal thickness of kerotoconus eyes with a high–speed corneal and anterior segment optical coherence tomography (CAS–OCT) system. Methods: We used a new generation of high–speed (2000 a–scan/sec) 1.3–micron wavelength CAS–OCT prototype with an internal fixation device. The cornea was scanned with a radial spoke arranged pattern of 8 lines covering a 8mm diameter corneal area centered on the apex reflection. Each 1024 axial–scan dataset was acquired within 0.5 second. We developed automated computer algorithms to reconstruct the 3–dimensional cornea and provide measurements. Corneal thickness was measured normal to the anterior surface and presented as color pachymetry maps. The thickness and location of thinnest cornea was recorded. 28 eyes of 15 kerotoconus subjects were scanned 3 times. 10 eyes of 5 normal subjects were also scanned to serve as a comparison. Results: The population average for minimum corneal thickness of kerotoconus patients was 450 +/– 55 micron, statistically significantly lower than that of the normal group (550 +/– 50 micron, p<0.001). The average distance from the thinnest cornea to the center of the scan was 984 +/– 436 micron in the kerotoconus group and was 602 +/– 406 micron in the normal group. The thinnest cornea located infero temporal to the center of the scan in most of the eyes (93% in the in the kerotoconus group, 70% in the normal group). Conclusions: High–speed OCT provided non–contact, rapid, and repeatable pachymetric mapping over a wide area. Cornea thinkness information, along with the corneal shape information, could be useful for kerotoconus diagnosis and management.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • cornea: clinical science • keratoconus