Topo-pachimetric Accelerated Epi-On Cross-linking Compared to Dresden Protocol Using Riboflavin With Vitamin E TPGS

Study Overview
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Brief Summary
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In the present study the investigators compare the clinical outcome corneal cross linking with either the stand-ard Dresden (sCXL) or the accelerated custom-fast (aCFXL) ultraviolet A irradiation protocol using riboflavin-D-α-Tocopheryl polyethyleneglycol1000 succinate for progressive keratoconus.

Official Title
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Topo-pachimetric Accelerated Epi-On Cross-linking Compared to Dresden Protocol Using Riboflavin With Vitamin E TPGS: Results of a 2-year Randomized Study

Conditions
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Keratoconus

Intervention / Treatment
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* Other: accelerated custom-fast CXL
* Other: Standard CXL


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: documented progressive keratoconus changes in uncorrected distance visual acuity (UDVA) above 1.00 D Corrected distance visual acuity (BCVA) above 1.00 D spherical equivalent greater than 0.50 D Exclusion Criteria: Corneal pachymetry of less than 400 µm less than 2000 cells/cm2, corneal scarring, nystagmus or any motility disorder that prevented a fixed gaze during the examination Current contact lens use

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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: sCXL<br>Standard protocol of Dresden Riboflavin-VEPTGS solution applied every 2 mins during UV UVA fluence of 3mW/cm2 UVA Irradiation time 30 minutes | Other: Standard CXL<br>* The standard CXL procedure has been carried on following the Dresden protocol<br>|
| Experimental: aCFXL<br>Accelerated custom fast CXL protocol. The protocol has been developed on a published mathematical model that takes into consideration objective variables such as the equation governing the UVA-induced riboflavin con-sumption rate and the corneal thickness at its thinnest point. Riboflavin-VEPTGS solution: Epithelial lavage before UV UVA fluence of 1.8 ±0.9 mW/cm2 UVA Irradiation time 10 ± 1.5 minutes | Other: accelerated custom-fast CXL<br>* The accelerated custom fast CXL (aCFXL) has been developed on a published mathematical model that takes into consideration objective variables such as the equation governing the UVA-induced riboflavin consumption rate and the corneal thickness at its thinnest point. By knowing both values, the mathematical model allows to objectively calculate both the exact UVA irradiation value (intensity), expressed in mW/cm2, and the irradiation time<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Topographical parameters | Maximum keratometry: diopters Mean keratometry: diopters Minimum corneal tickness: diopters | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Refractive parameters | Corrected distance acuity (BCVA): Logarithm of the Minimum Angle of Resolution (logMAR) | 2 years | 
| Refractive parameters | Spherical equi-valent: diopters Refractive cylinder magnitude: diopters | 2 years | 
| Biomechanical parameters | Corneal hysteresis: mmHg | 2 years |