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

Democritus University of Thrace

Status: Completed

Conditions: Keratoconus

Treatments: Procedure: Corneal Collagen Cross-Linking combined with t-PRK; Procedure: Corneal Collagen Cross-Linking (CxL)

Study type: Interventional

Funder types: Other

Identifiers

NCT01527721

3/2/2012 37

Details and patient eligibility

About

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).

Full 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.

Enrollment: 32 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

---

32 participants in 2 patient groups

CxL group

Experimental group

Description:

Volunteers of this group received CxL treatment.

Treatment:

Procedure: Corneal Collagen Cross-Linking (CxL)

tCxL group

Experimental group

Description:

Volunteers of this group received CxL combined with t-PRK treatment

Treatment:

Procedure: Corneal Collagen Cross-Linking combined with t-PRK