Structural retinal and choroidal changes in keratoconus: A cross-sectional OCT study stratified by ABCD grading

Area of Science:

• Ophthalmology
• Corneal Diseases
• Retinal Imaging

Background:

• Keratoconus (KC) is a progressive corneal ectasia.
• Anterior segment changes in KC are well-documented.
• Posterior segment involvement in KC requires further investigation.

Purpose of the Study:

• To evaluate posterior segment structural changes in keratoconus (KC) patients.
• To assess the association between anterior and posterior segment parameters across KC severity stages using the ABCD classification system.

Main Methods:

• Cross-sectional observational study of 124 KC eyes and 32 control eyes.
• KC severity staged I-IV using the ABCD grading system.
• Ophthalmic evaluation included corneal tomography, enhanced depth imaging OCT, and ocular biometry.

Main Results:

• Reduced Retinal Nerve Fiber Layer (RNFL) thickness in KC eyes compared to controls (P=0.008).
• Progressive RNFL decline observed from KC stage I to IV.
• No significant associations found between anterior segment parameters and posterior segment measurements (P>0.05).

Conclusions:

• Keratoconus is associated with significant RNFL thinning, indicating posterior segment involvement.
• Retinal and choroidal thicknesses are largely unaffected in keratoconus patients.
• The ABCD classification system aids in staging KC and evaluating associated structural changes.