Factors affecting outcomes of corneal collagen crosslinking treatment

Abstract

Purpose To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus. Methods This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (o30 andZ30 years), gender, preoperative corrected distance visual acuity (CDVA, o0.3 and Z0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, o54 and Z54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (o450 and Z450 mm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment. Results In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (Po0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (Z0.3 logMAR) experienced more visual improvement after CXL treatment (Po0.001). However, an age Z30 years and a baseline thinnest pachymetry less than 450 mm were found significantly associated with more flattening in maximum keratometry (P ¼ 0.024, P ¼ 0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P40.05). Conclusions In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.

Comment on, ‘Factors affecting outcomes of corneal collagen crosslinking treatment’

“…Although we agree that age influences the outcome of the treatment, 2 our results, stratified into four subgroups (o18 years, 18-28 years, 29-39 years, and over 40 years), demonstrated a better functional and morphological outcomes in the population between 18 and 39 years of age.…”

“…We found that patients with a worse preoperative corrected distance visual acuity (CDVA, r20/40 Snellen equivalent) tend to experience more visual improvement after CXL treatment (Po0.001). 2 However, an older age (Z30 years) and a thinner cornea (thinnest pachymetry o450 mm) appear to be positive preoperative predictors for more flattening in maximum keratometry (P ¼ 0.024 and P ¼ 0.005, respectively). 2 Similarly, Vinciguerra et al 3 reported that age between 18 and 39 years has positive effect on the outcomes of CXL, and they found a significant association between the thinnest pachymetry and sphere change after CXL treatment.…”

“…2 However, an older age (Z30 years) and a thinner cornea (thinnest pachymetry o450 mm) appear to be positive preoperative predictors for more flattening in maximum keratometry (P ¼ 0.024 and P ¼ 0.005, respectively). 2 Similarly, Vinciguerra et al 3 reported that age between 18 and 39 years has positive effect on the outcomes of CXL, and they found a significant association between the thinnest pachymetry and sphere change after CXL treatment. Unlike the studies of Vinciguerra et al 3 and Greenstein et al, 4 our analysis showed no significant relation between initial maximum keratometry and postoperative improvement in visual acuity and maximum keratometry.…”

“…2 The rationale of our study was to determine the preoperative patient characteristics affecting visual and topographic outcomes of corneal collagen crosslinking (CXL) for progressive keratoconus. We found that patients with a worse preoperative corrected distance visual acuity (CDVA, r20/40 Snellen equivalent) tend to experience more visual improvement after CXL treatment (Po0.001).…”

“…4 To avoid these complications it is advisable to check intraoperative CCT and in case of the thickness reducing o400 mm, use swelling solutions. 2 Vetter et al 5 in a recent report did not find a correlation between osmolality and CCT after riboflavin eye drop application but found an inverted correlation between dextran concentration and CCT. The authors explained that hypertonicity and hypotonicity of solutions do not have a significant effect on stromal thickness because only 2-3% of the corneal stroma volume consists of cells, conversely dextran possesses a high affinity for water because of its abundant hydrophilic hydroxyl groups leading to deswelling beyond the physiological level.…”