DEC 17, 2018
This study evaluates the densitometric histories of patients with keratoconus who underwent corneal crosslinking (CXL).
Corneal tomography and densitometry measurements were performed before and after accelerated (18-mW/cm2 irradiance for 5 minutes) epi-off CXL in 22 eyes of 22 patients to evaluate the duration of postoperative corneal haze. The authors compared preoperative and postoperative corneal densitometry, maximum keratometry (Kmax) and central corneal thickness. Patients were followed for an average of 3.5 years.
The duration of corneal haze was about 18.2 months at the first zone of 0 to 2 mm, and about 10.9 months at the second zone of 2 to 6 mm. There was no change in Kmax between the preoperative period and the time at which corneal haze resolved. Kmax was lower at 1 year after haze resolution than at the time when haze resolved (62.0 D to 61.2 D; P = 0.008 at the first zone; 63.6 D to 62.5 D; P = 0.016 at the second zone).
Central corneal thickness decreased between the preoperative period and the time at which corneal haze resolved (470.8 μm to 464.8 μm, P = 0.047 at the first zone; 465.0 μm to 454.7 μm, P = 0.001 at the second zone), but it remained unchanged after haze resolution (P = 0.146 at the first zone; P = 0.067 at the second zone).
The study size was very small. Perhaps due to this reason alone, no attempt was made to correlate duration of haze with magnitude of corneal flattening post-haze resolution.
Corneal crosslinking halted keratoconus progression when detectable haze was present, followed thereafter by continuous corneal flattening observed 1 year after haze resolution. Thinning of the cornea occurred only during the period of postoperative haze but then remained stable.