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Customized Corneal Crosslinking for Keratoconus – One Year Results

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First Author: J.Quadrado Gil PORTUGAL

Co Author(s):    R. Pinheiro   E. Costa   C. Tavares   A. Rosa   M. Quadrado   J. Murta     

Abstract Details

Purpose:

Conventional corneal cross-linking treatments have shown to be able to stabilize keratoconus progression but its inability to rehabilitate vision remains an important insufficiency. Recent investigations indicate that higher levels of UVA induce more flattening, favoring individualized treatment plans that include a local augmentation of the treatment in the most affected areas. We report on the use of a novel, customized irradiation procedure to treat KC patients. We hipothesize that using focal instead of broad-zone CXL will lead to greater localized cone flattening, less corneal irregularity, and better visual outcomes.

Setting:

Unidade de Oftalmologia de Coimbra (UOC), Hospital da Luz Coimbra, Coimbra, Portugal

Methods:

Prospective case series enrolling eyes with progressive keratoconus and central corneal thickness exceeding 380 um. Customized irradiation was performed with the KXL-II platform (Avedro, Waltham, MA, USA) and designed as the superposition of 3 concentric areas centered on the thinnest point on Pentacam maps (Oculus Optikgerate GmbH, Wetzlar, Germany). Treatment starts from a broad-beam irradiation, continuously masked until only the central inner circle is irradiated. Energy exposure is 5.4J/cm2 in the outer circle and increases centripetally to 7.2J/cm2 and 10J/cm2. Corrected distance visual acuity (CDVA), refractive results, and Scheimpflug tomographies were assessed after a minimum follow-up of 12 months.

Results:

We enrolled 26 eyes of 24 patients. Mean follow-up was 13.71±1.94 months. Pre-operative mean central corneal thickness was 433.46±43.61um. Mean BSCVA improved significantly from 0.42±0.23 to 0.24±0.16 logMAR (p<0.01), with 23 of the 26 eyes (88.46%) retaining or improving BSCVA.The maximal curvature (Kmax) decreased slightly but significantly from 58.81±6.85D to 58.46±6.91D (p=0.04). The Index of Surface Variation (ISV) also significantly decreased from 102.96±28.32 to 83.09±29.80 (p<0.01). A significant correlation was noted between improvement in visual acuity and ISV reduction (p=0.03). After 1 year, 25 of 26 eyes (96.15%) showed no signs of progression No significant complications were noted.

Conclusions:

Individualized topography-based crosslinking has the potential to be an effective tool in the treatment of keratoconus patients. One year after surgery, patients showed a significant improvement in visual acuity while achieving stabilization of disease progression. Topographic results seem to show positive microstructural stromal changes that result in a reduction of surface irregularity, suggesting an advantage in the use of customized treatments.

Financial Disclosure:

... gains financially from competing product or procedure, ... travel has been funded, fully or partially, by a competing company, ... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... research is funded, fully or partially, by a competing company, ... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... receives non-monetary benefits from a competing company, ... receives non-monetary benefits from a company producing, developing or supplying the product or procedure presented, ... receives consulting fees, retainer, or contract payments from a competing company, ... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, ... is employed by a for-profit company with an interest in the subject of the presentation, ... is employed by a competing company, ... has significant investment interest in a competing company, ... has significant investment interest in a company producing, developing or supplying product or procedure presented, ... gains financially from product or procedure presented