Compare of the scleral morphology between healthy populations and keratoconus patients using optical coherence...

To scan and measure the scleral morphology of healthy eyes and keratoconus eyes using Optical Coherence Tomography (OCT), evaluate the differences in scleral morphology between them, and provide a more scientific basis for the precise fitting of scleral lenses.

A total of 85 subjects who were admitted to the First Affiliated Hospital of Army Medical University from March 2024 to November 2024 and underwent OCT examination were selected as the research subjects. They were divided into a healthy group (64 cases, 120 eyes) and a keratoconus group (21 cases, 40 eyes) according to whether they had the disease. Each subject underwent anterior segment OCT examination to measure and obtain corneoscleral parameters such as the Corneoscleral Junction Angle (CSJA), Scleral Angle (SA), Sagittal Height (SH), and Scleral Toricity (ST). The differences in the above parameters at different chord lengths and in different orientations were compared, and these parameters of the two groups of subjects were also compared.

In both groups, the CSJA was the largest in the superior position and the smallest in the nasal position, and the difference was statistically significant (P<0.05). The average nasal CSJA in the keratoconus group was 175.6°, while that in the healthy group was 177.0°, and the difference was statistically significant (P<0.05). In the healthy group, at a chord length of 10.0 mm, the SA was the largest in the superonasal position and the smallest in the temporal position; at chord lengths of 12.8 mm, 14.0 mm, and 15.0 mm, the SA was the largest in the temporal position and the smallest in the superonasal position, and the difference was statistically significant (P<0.05). In the keratoconus group, at a chord length of 10.0 mm, the SA was the largest in the superonasal position and the smallest in the temporal position; at a chord length of 12.8 mm, the SA was the largest in the temporal position and the smallest in the superonasal position; at chord lengths of 14.0 mm and 15.0 mm, the SA was the largest in the inferotemporal position and the smallest in the nasal position, and the difference was statistically significant (P<0.05). At chord lengths of 10.0 mm, 12.8 mm, 14.0 mm, and 15.0 mm, the SH in the keratoconus group was greater than that in the healthy group, and the difference was statistically significant (P<0.05). The ST of both groups increased with the increase of the chord length. In the healthy group, the ST increased from 0.06 mm at chord length of 10.0 mm to 0.16 mm at chord length of 15.0 mm. In the keratoconus group, the ST increased from 0.11 mm at chord length of 10.0 mm to 0.20 mm at chord length of 15.0 mm, and the difference was statistically significant (P<0.05); at chord lengths of 10.0 mm, 12.8 mm, 14.0 mm, and 15.0 mm, the ST in the keratoconus group was greater than that in the healthy group, and the difference was statistically significant (P<0.05).

The sclera is generally irregular in shape, especially extremely asymmetric in the horizontal direction. Moreover, as the chord length increases, this irregularity becomes more obvious. Compared with healthy eyes, the scleral morphology of keratoconus eyes shows more significant irregularities.