Simultaneous Wavefront-Guided Photorefractive Keratectomy With Accelerated Corneal CXL With Riboflavin: A Step Ahead in Management of Keratoconus
Purpose
To evaluate visual, refractive and topographic outcome after simultaneous wavefront-guided photorefractive keratectomy (PRK) with accelerated corneal collagen crosslinking (C3R) in eyes with mild to moderate keratoconus.
Methods
Prospective case series conducted at Sankara Eye Centre, Coimbatore, India included 32 eyes of 25 patients. Inclusion criteria were patients with keratoconus older than 18 years with thinnest corneal pachymetry greater than 400 µm. Advanced keratoconus cases in whom wavefront map was not obtained and in whom post PRK expected residual bed thickness was less than 350 µm were excluded. All patients underwent wavefront guided PRK. Customization was performed based on manifest refraction, wavefront refraction and higher-order aberrations. Adjusting attempted correction and ablation zone could lower the maximum depth of tissue removed. Size of optic zone ranged from 4 to 6 mm depending on the location of cone on topographic map. PRK was immediately followed by accelerated C3R. Results were evaluated in terms of visual, refractive and topographic outcomes.
Results
Mean follow-up was 12 months (range 6 to 15). Visual outcome was measured in change in uncorrected distance visual acuity (UCVA) and best corrected distance visual acuity (BCVA). UCVA improved significantly from preoperative mean value of 0.907 to 0.252 Logmar units (p value < 0.01). BCVA improved from preoperative mean value of 0.196 to 0.082 Logmar units. At last follow up, 23 out of 32 eyes (72%) gained 3 or more lines of UCVA. Refractive outcome was change in manifest spherical equivalent refraction which improved significantly from -3.34D to -0.60D (p value < 0.01). Topographic outcome was flattening of simulated keratometry values. Mean steepest keratometry was reduced significantly from 48.10D preoperatively to 44.36 D at last follow up (p value <0.01). Corneal higher-order aberrations (HOA) were significantly reduced.
Conclusion
Results in this study shows that simultaneous wavefront-guided PRK with accelerated C3R can halt the progression of keratoconus and provide better refractive, topographic and HOA results by reshaping the cornea and flattening and regularizing the anterior corneal surface.