Visual recovery after corneal crosslinking for keratoconus: a 1-year follow-up study

To evaluate visual recovery and intraocular straylight in keratoconus patients 3 months and 1 year after corneal crosslinking (CXL) PATIENTS AND METHODS: Thirty-three eyes of 28 consecutive patients with mild to moderate keratoconus were included. The following were assessed at baseline, 3 months and 1 year after CXL: corrected distance visual acuity (CDVA), intraocular straylight, spherical equivalent (SE), keratometry (Kmax and K min (Diopters D and axis), the regularity index and pachymetry. Changes from baseline were calculated using mixed linear regression models.

The CDVA remained unchanged 3 months after CXL (-0.003 (95 % CI: -0.038 to 0.044); p = 0.880) and improved after 1 year (-0.042 (95 % CI: -0.078 to -0.007; p = 0.021)). The mean straylight value increased significantly by 0.27 (95 % CI: 0.18 to 0.35; p < 0.001) 3 months after CX and normalized to preoperative values after 1 year (0.06 (95 % CI: -0.03 to 0.14; p = 0.215)). SE improved from the mean preoperative value of -2.61 D (95 % CI: -3.83 to -1.39) by 1.95 (95 % CI: 1.03 to 2.86; p < 0.001) at 3 months and remained stable at the 1-year follow-up visit (2.17 (95 % CI: 1.21 to 3.12; p < 0.001)). Parameters of of keratometry changed only minimally. The regularity index remained almost unchanged at 3 months (2.45 (95 % CI: -4.97 to 9.88; p = 0.503)) and decreased by 6.97 (95 % CI: -14.08 to 0.14; p = 0.054). Pachymetry decreased by 44.0 μm (95 % CI: 56.1 to 31.9; p < 0.001) at 3 months and almost returned to preoperative values at 12 months (-11.3 μm (95 % CI: -27.9 to 5.3; p = 0.175)).

In accordance with the decrease in CDVA and patients' complaints of disability due to glare, intraocular straylight increased 3 months after surgery. One year after CXL, there was an increase in CDVA due to an improved SE and regularity index, and intraocular straylight had normalized.