Simultaneous Wavefront-Guided Transepithelial Photorefractive Keratectomy And Accelerated Cross-Linking In Keratoconus Patients With Ultra-Thin Cornea

To observe the efficacy and safety of simultaneous wavefront-guided transepithelial photorefractive keratectomy (WG-TransPRK) and accelerated corneal collagen cross-linking(A-CXL) in keratoconus (KC) patients with ultra-thin corneas.

 CXL is a proven modality to stabilize kerectasia by improving stiffness of the cornea and halting progression of KC . However, 400μｍcorneal thickness limits ultra thin KC from the CXL treatment because of possible corneal endothelial loss. Moreover,visual function does not improve much with this treatment alone, necessitating the need for additional refractive procedures. Thus, surgical techniques in combination with CXL have come into practice, leading to better visual outcomes.

In this retrospective study,sixteen eyes of 10 KC patients (Stage III and IV) with a minimum corneal thickness of < 400µm after removal of the corneal epithelium were recruited from Gansu Aier Ophthalmology and Optometry Hospital , over the period from January 2023 to December 2023. All patients underwent simultaneous WG-Trans PRK and A-CXL, which a SMILE-Derived Lenticule placed over the cornea before A-CXL. Visual acuity, refractive status, topography, confocal microscopy and aberrations  were  examined  before  treatment and 1 week,1  month, 3 months,6 months,and 12 months after surgery.Data were analyzed by paired t test.

Twelve months after the surgery, the average UCVA improved from 0.88±0.33 LogMAR to 0.36±0.28 LogMAR (P<0.001) and The average BCVA improved from 0.20±0.23 LogMAR to 0.06±0.05 LogMAR(P=0.015). The BCVA improved by 3 lines in all eyes, 4 or more lines in 6 eyes (60%).The K1,K2 spherical equivalent of the cornea were reduced from 48.15± 2.46D and 51.14±2.33 D to 47.03±2.21D and 49.57±2.19D,respectively. The SIF (Anterior surface asymmetry index)、SIB (Posterior surface asymmetry index) and aberration parameters ( total corneal higher-order aberrations、coma、spherical abberation) decreased in the 6 mm diameter analysis area (P<0.05). No significant change was detected in the endothelial cell density HEX and CV after surgery.

WG-TransPRK with simultaneous accelerated corneal collagen cross-linking(A-CXL) is safe and effective for the treatment of KC patients with ultra-thin corneas. Trans PRK can maintain corneal biomechanical stability to the greatest extent and better reinforcement was achieved by crosslinking directly at the stroma after removal of the epithelium.The customization of wavefront-guided keratectomy is able to select the corneal higher-order aberrations for correction intelligably ,which is very important for keratoconus patients to save valuable corneal tissue while correcting higher-order aberrations,which shows good safety and efficacy.