Extremely asymmetric ectasia: Tomographically unilateral keratoconus

Area of Science:

• Ophthalmology
• Corneal Imaging
• Keratoconus Research

Background:

• Keratoconus (KC) is a progressive corneal ectasia.
• Tomographically unilateral KC, where only one eye shows clear signs of KC, presents diagnostic challenges.
• Understanding the characteristics of unilateral KC is crucial for diagnosis and understanding KC etiology.

Purpose of the Study:

• To investigate the clinical and tomographic characteristics of apparently stable, tomographically unilateral keratoconus (KC).
• To compare unaffected eyes of unilateral KC patients with healthy controls and affected KC eyes.

Main Methods:

• Retrospective case-control study involving tomographically unilateral KC cases with ≥3 years follow-up.
• Comparison with healthy controls and bilateral KC cohorts using Pentacam imaging.
• Assessment of risk factors and 25 Pentacam features.

Main Results:

• 18 (1.8%) tomographically unilateral KC cases were identified.
• Higher prevalence of eczema and asthma in unilateral KC patients compared to bilateral KC.
• Unaffected unilateral eyes showed no significant differences from healthy eyes.
• Affected unilateral eyes had comparable ectatic features but lower high-order aberrations than bilateral KC eyes.

Conclusions:

• The study supports the existence of tomographically unilateral keratoconus.
• Insights into the development of tomographic unilaterality may elucidate KC etiology.
• Further research into the mechanisms underlying unilateral KC is warranted.