First Author: H.Matalia INDIA
Co Author(s): S. D A. Ranganath G. Singh R. Shetty
Purpose:
Corneal Collagen Cross-linking using riboflavin and UV-A irradiation (CXL) has become a norm to arrest the progression of corneal ecstatic disorders like keratoconus and post-lasik ectasia. The standard corneal collagen cross-linking involves 30 minutes exposure to UV-A (3mW/cm2). Newer accelerated corneal collagen cross-linking (ACXL) using the Avedro Inc.s KXL system reduces this exposure time to less than 3 minutes by using 30mW/cm2 of UV-A energy. The purpose of this study was to compare the loss of transparency (haze) produced by conventional CXL compared to ACXL, in view of high energy delivered to the corneal stroma in the latter and the theoretical risk of increased stromal haze thereby.
Setting:
Department of Cornea, Refractive Surgery & Ocular Surface, Narayana Nethralaya Super Speciality Eye Hospital & Post Graduate Insitute of Ophthalmology, Bangalore, India
Methods:
It was a prospective interventional, age-matched case-control study. The study group comprised of patients with keratoconus undergoing ACXL and the control group had age matched consecutive patients undergoing CXL. The ACXL procedure included 20 minutes of soak time with 0.1% Riboflavin (Vitamin B2) followed by UV-A exposure of 30mW/cm2 for 3 minutes. The CXL involved 30 minutes of soak time with 0.1% Riboflavin (Vitamin B2) followed by 30 minutes of exposure to UV-A (3mW/cm2). The amount of stromal haze produced by both procedures was evaluated and quantified by using densitometry on Pentacam (Oculus Inc.). The study duration was 1-month. All patients underwent densitometry test at preop, 1-week and at 1-month.
Results:
15 eyes of 15 patients with keratoconus (M:F = 13:2) underwent ACXL, which was compared with 14 eyes of 14 age matched patients with keratoconus who underwent CXL. Mean age of the patients was 23.5 years. The densitometry measured on Pentacam in ACXL group showed initial significant increase of densitometry value at 1-week, which reduced to slightly higher than preoperative value at 1 month [Preop: 21.56?3.70, 1-week: 41.13?6.57, 1-month: 28.71?4.48]. This change was similar to which observed with the CXL group [Preop: 22.76?4.46, 1-week: 42.37?15.92, 1-month: 36.45?11.27]. However, at 1-month, there was a difference between CXL and ACXL with CXL group showing slightly more densitometry values [difference 7.74, 95%CI: 0.94-14.54]. Two patients from CXL group show increase in the densitometry values at 1-month compared to 1-week. The haze in CXL group was more variable and unpredictable, whereas the haze with the ACXL group was more predictable.
Conclusions:
With this study we conclude that Accelerated Corneal Collagen Cross-linking as a treatment of keratoconus results in less corneal haze as compared to the conventional corneal collagen cross-linking. FINANCIAL DISCLOSURE?: No
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