Scleral shape and its correlation with corneal parameters in keratoconus

Area of Science:

• Ophthalmology
• Corneal Imaging
• Biomechanical Analysis

Background:

• Keratoconus is a progressive thinning and ectasia of the cornea.
• Scleral changes in keratoconus are not well understood.
• Corneal shape and scleral shape may be interconnected in keratoconus.

Purpose of the Study:

• To investigate the relationship between corneal tomographic parameters and scleral shape in keratoconus.
• To determine if scleral asymmetry correlates with anterior and posterior corneal metrics.

Main Methods:

• Corneal imaging was performed using Pentacam HR and Eye Surface Profiler (ESP).
• Three-dimensional corneoscleral maps were generated to calculate sagittal height.
• Pearson correlation coefficient was used to assess associations between corneal parameters and scleral asymmetry.

Main Results:

• Anterior corneal parameters, including flattest and steepest keratometry, showed significant correlation with scleral asymmetry (r>0.5, p < 0.05).
• Anterior astigmatism and posterior corneal curvature/thickness did not correlate with scleral irregularity.
• The steepest regions of the central cornea, peripheral cornea, and sclera demonstrated a common angular orientation (r = 0.92; p < 0.001).

Conclusions:

• Anterior corneal parameters are associated with scleral asymmetry in keratoconus.
• The orientation of the steepest corneal area aligns with the sclera in keratoconus eyes.