Our experience with Athens protocol - simultaneous topo-guided photorefractive keratectomy followed by corneal collagen cross linking for keratoconus

Shreyas Shah, Sujatha Mohan, Mohan Rajan, Bina John, Vini Badlani


Background: Corneal collagen cross linking (CXL) has become an established modality of treatment for progressive Keratoconus. Aim of the study was to analyze visual outcome, refractive status and changes in corneal curvature following simultaneous topography-guided photorefractive keratectomy (PRK) followed by corneal collagen cross-linking with riboflavin (C3R) for keratoconus in a tertiary eye care hospital.

Methods: All patients underwent manifest refraction, uncorrected visual acuity (UCVA), Best corrected visual acuity (BCVA), slit lamp examination, corneal topography, ultrasound pachymetry and fundus evaluation pre operatively. 39 eyes of 27 patients with keratoconus underwent simultaneous topo guided PRK + CXL were followed up upto 6 months.

Results: Mean UCVA improved from 0.81 log mar units pre-operatively to 0.43 log mar units at the end of 6 months. Preoperative BCVA was maintained or improved in 37 eyes (94.87%) and BCVA decreased by more than 1 line in 2 eyes (5.12%) post-operatively. The mean BCVA improved from 0.2 log mar units pre-operatively to 0.1 log mar units at the end of 6 months. The mean preoperative manifest refraction spherical equivalent reduced from -3.1±2.3D to -1.4±1.3D postoperatively. The mean steepest K reading decreased from 47.8±4.2D pre-op to 45±3.3D at the end of 6 month. Similarly, mean flat keratometry readings reduced significantly from 44.8±3.5D preoperatively to 42.2±2.8D at the last follow-up visit postoperatively.

Conclusions: Combined topo-guided PRK+CXL is an effective approach in treating patients with keratoconus. It biomechanically stabilizes the cornea, improves the corneal contour, reduces irregular astigmatism and offers a better quality of vision.


PRK, Zernike compensation, Athens protocol, Corneal collagen cross linking with riboflavin

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