Astigmatic vector analysis after combined surgery for forme fruste keratoconus

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Forme fruste keratoconus presents diagnostic challenges.
• Astigmatic changes are a key concern in keratoconus management.
• Combination treatments aim to correct refractive errors and halt disease progression.

Purpose of the Study:

• To evaluate astigmatic changes in forme fruste keratoconus after PRK and CXL.
• To apply Alpins vector analysis for objective assessment of astigmatism.
• To determine the efficacy of combined PRK and CXL in managing forme fruste keratoconus.

Main Methods:

• Retrospective analysis of 27 eyes from 20 patients with forme fruste keratoconus.
• Combination treatment with photorefractive keratectomy (PRK) followed by corneal collagen crosslinking (CXL).
• Assessment of visual acuity, spherical error, and astigmatism preoperatively and at 12 months postoperatively using Scheimpflug imaging and Alpins vector analysis.

Main Results:

• LogMAR corrected distance visual acuity improved significantly (p < 0.001).
• Corneal astigmatism showed a difference vector (DV) of 0.49 D at axis 13°.
• Manifest astigmatism showed a DV of 0.10 D at axis 16°, with a geometric mean correction index (CI) of 0.89.

Conclusions:

• Combination PRK and CXL may benefit forme fruste keratoconus patients with adequate corneal thickness.
• Alpins vector analysis provides an objective method to evaluate astigmatic outcomes.
• This combined approach shows potential for improving visual function and managing astigmatism.