Accelerated Versus Standard CXL in the Treatment of Ectasia Post Refractive Surgery and Penetrating Keratoplasty.

Study Overview
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Brief Summary
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WHAT WAS KNOWN *Standard CXL is the common procedure for treating progressive corneal ectasia. Modifications of the standard protocol were introduces to reduce its complications especially long exposure to ultraviolet rays. The Accelerated protocol, while believed to overcome this issue with comparable outcomes, has not been studied fully in patients with ectasia following corneal refractive surgery and penetrating keratoplasty. WHAT THIS PAPER ADDS Accelerated CXL is as safe and effective as the Standard CXL in halting the progression of ectasia post refractive surgery and penetrating keratoplasty with the benefit of: reduced ultraviolet exposure, reduced operation time, and reduced patient discomfort.

Detailed Description
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Purpose: The aim of this study is to compare the clinical outcomes of the Standard CXL and the AC CXL in patients with progressive corneal ectasia post refractive surgery and penetrating keratoplasty. Setting: Menoufia University Hospital, Egypt Design: Prospective, randomised comparison. Methods: Patients scheduled to receive either Standard CXL (3mW/cm2 for a period of 30 min) or Accelerated CXL (18mW/cm2 for a period of 5 min).The main outcomes for comparison were the change in; Maximum-K reading (K-max), manifest refractive spherical equivalent (SE), central corneal thickness (CCT), and the best corrected distance visual acuity (CDVA).

Official Title
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Accelerated Versus Standard Corneal Cross Linking in the Treatment of Ectasia Post Refractive Surgery and Penetrating Keratoplasty: A Long Term Randomized Trial.

Conditions
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Refractive Surgery

Intervention / Treatment
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* Device: Cross linking


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Eligible patients were: adults aged above 18 years. They have been diagnosed clinically with progressive corneal ectasia following refractive surgery procedure (LASIK, PRK, ReLex smile), or penetrating keratoplasty CCT above 400µ. Exclusion Criteria: The exclusion criteria involved: history of herpetic ocular diseases (including herpes simplex virus and varicella zoster virus) in the study eye active or recurrent ocular disease in either eye (e.g., uveitis, chronic moderate to severe blepharitis or severe dry eye) or sight-threatening diseases (e.g., previous retinal or optic nerve diseases) that would interfere with the interpretation of the study data.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Accelerated Cross Linking<br>Ultraviolet A radiation of 365 nm wavelength (CCL-365 vario, Peschke Meditrade GmbH, Switzerland), and an irradiance of 18mW/cm2 (spot size 7mm), at a distance of 45 mm from the cornea, was applied for a period of 5 min, delivering a dose of 5.4 J/cm2. | Device: Cross linking<br>* Cross linking strategy either standard or accelerated<br>|
| Active Comparator: Standard Cross linking<br>Ultraviolet A radiation of 365 nm wavelength (CCL-365 vario, Peschke Meditrade GmbH, Switzerland), and an irradiance of 3mW/cm2 (spot size 7mm), at a distance of 45 mm from the cornea, was applied for a period of 30 min, delivering a dose of 5.4 J/cm2. | Device: Cross linking<br>* Cross linking strategy either standard or accelerated<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| K-max changes | The main outcomes for comparison were the change in; Maximum-K reading (K-max), Patients were followed up clinically on the first day, first week, one month, 6 months and 12 months postoperatively | 12 post treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| manifest refractive spherical equivalent (SE) in Diopter power | The secondary outcomes for comparison were the change in, manifest refractive spherical equivalent (SE). Patients were followed up clinically on the first day, first week, one month, 6 months and 12 months postoperatively | 12 months postoperatively |