[Subclinical keratoconus diagnosis by elevation topography]

Area of Science:

• Ophthalmology
• Corneal Imaging
• Refractive Surgery

Background:

• Keratoconus is a progressive corneal ectasia.
• Subclinical keratoconus poses a risk for post-refractive surgery complications.
• Early detection is crucial for patient management.

Purpose of the Study:

• To determine the most effective Orbscan Corneal Topography System parameters for identifying subclinical keratoconus.
• To differentiate between normal, subclinical, and clinical keratoconus using specific corneal measurements.

Main Methods:

• Corneal topography data from 35 clinical keratoconus patients, 14 subclinical keratoconus patients, and 35 myopic controls were analyzed.
• Evaluated parameters included apex placement, anterior and posterior corneal elevation, minimal corneal thickness, anterior chamber depth, and corneal diameter.
• Statistical analysis was performed to compare measurements between groups.

Main Results:

• Significant differences in anterior and posterior corneal elevation were observed between all groups (p<0.001).
• Minimal corneal thickness and anterior chamber depth also showed significant differences across the three groups.
• The inferotemporal sector was the most common apex location (53%) in keratoconus patients.

Conclusions:

• Orbscan parameters like anterior/posterior elevation, minimal corneal thickness, and anterior chamber depth are effective in distinguishing between normal, subclinical, and clinical keratoconus.
• These findings are vital for identifying individuals at higher risk of developing secondary keratectasia after corneal refractive surgery.
• The Orbscan system provides valuable data for screening and risk assessment in keratoconus detection.