Blurring Strength & Aberrometric Changes Following Corneal Cross-linking (CxL) and CxL Combined With Photorefractive Keratectomy (PRK) in Keratoconus

Not Applicable

Completed

• Conditions: Keratoconus
• Interventions: Procedure: Corneal Collagen Cross-Linking combined with t-PRK; Procedure: Corneal Collagen Cross-Linking (CxL)

• Registration Number: NCT01527721
• Lead Sponsor: Democritus University of Thrace

Brief Summary

Primary objective of this study was to assess the impact of the two prevalent therapeutic options, CxL and CxL combined with topography-guided photorefractive keratectomy (t-PRK), on both anterior and posterior corneal High order aberations (HOAs).

Detailed Description

The Pentacam Classic (Oculus Optikgerate GmbH, Heidelberg, Germany, software version 1.14r04) was used for the sake of the study.32 patients with keratoconus were included in the study. Of them, 19 patients underwent CxL treatment (CxL group), while the rest 13 patients underwent CxL combined with t-PRK (tCxL) \[tCxL group\]. If both eyes were eligible, only one eye was enrolled in the study.Regarding Scheimpflug camera (Pentacam Classic, Oculus Optikgerate GmbH, Heidelberg, Germany, software version 1.14r04 ) measurements, acceptable maps had at least 10.0mm of corneal coverage. Moreover, images with extrapolated data in the central 9.0mm zone were excluded.

For both anterior and posterior corneal surfaces, Pentacam-derived HOAs parameters for both pupil diameters of 4mm and 6mm were calculated, as well as the HOA root mean square (RMS)values. Pentacam-derived HOA measurements were obtained one day prior to treatment and then one year post-op.The impact of the surgical technique (either CXL or tCXL) on spherocylindrical error was evaluated by power vector analysis as described before. Furthermore, manifest refractions comprising of sphere (S), cylinder (C) and axis (φ), were converted into three dioptric powers (M, J0 and J45). Moreover, we calculated the overall blurring strength (B) of the spherocylindrical error by measuring the length of the produced vector.

Study Timeline

• Study Start: 2010-09
• Primary Completion: 2011-12
• Study Completion: 2012-01
• Study First Submitted: 2012-02-03
• Study First Submitted QC: 2012-02-06
• Study First Posted: 2012-02-07
• Status Verified: 2017-01
• Last Update Submitted: 2017-01-14
• Last Update Posted: 2017-01-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 32

Inclusion Criteria

• progressive keratoconus

Exclusion Criteria

• glaucoma or suspicion for glaucoma,
• central corneal thickness (CCT) less than 400μm,
• K-readings more than 60D,
• history of herpetic keratitis,
• pregnancy or nursing,
• underlying autoimmune disease

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
tCxL group	Corneal Collagen Cross-Linking combined with t-PRK	Volunteers of this group received CxL combined with t-PRK treatment
CxL group	Corneal Collagen Cross-Linking (CxL)	Volunteers of this group received CxL treatment.

Primary Outcome Measures

Name	Time	Method
Higher order corneal aberations	1 year postoperatively

Trial Locations

Locations (1)

Eye Institute of Thrace (EIT); 🇬🇷 Alexandroupolis, Greece