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Customized corneal cross-linking for keratoconus – early clinical and morphological results

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First Author: J.Quadrado Gil PORTUGAL

Co Author(s):    R. Pinheiro   E. Costa   A. Rosa   C. Tavares   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 protocol 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 m. 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 preoperatively and at 3 and 6 months post-operative.

Results:

We included 26 eyes of 24 patients with a mean central corneal thickness of 448.00±39.93 m. Mean CDVA improved significantly from 0.4±0.25 to 0.26±0.13 logMAR (p=0.02). Average refractive astigmatism remained similar, from 2.73±2.48 D to 1.99±1.36 D (p=0.26) while the sphere changed from -3.15±3.56 to -3.41± 2.04 (p=0.03). The maximal curvature (Kmax) decreased from 58.92±4.68 D to 57.52 ± 7.01 D (p=0.26). The Index of Surface Variation (ISV) significantly decreased from 105.65±30.85 to 88.46±30.28 (p=0.02), a decrease that correlated with the improvement in CDVA (r=0.62, p=0.04). None of the patients developed significant complications during the course of the follow-up.

Conclusions:

Early results seem to show positive structural changes induced by a customized cross-linking treatment that modulates the intensity of the irradiation across different areas of keratoconic corneas. Six months after surgery, an improvement in visual acuity and a reduction in surface irregularity was noted, suggesting an advantage in the use of customized treatments.

Financial Disclosure:

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