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| Name | Class |
|---|---|
| Göteborg University | OTHER |
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The purpose of this study is to determine whether corneal collagen crosslinking is effective in the treatment of progressive keratoconus.
Keratoconus is a noninflammatory, asymmetrical, progressive corneal ectasia caused by biomechanical instability of the corneal stroma. Treatment modalities are primarily glasses or contact lenses. It has been estimated that one out of five patients will progress to such an extent that a corneal transplant is necessary to regain useful vision.
Corneal collagen crosslinking (CXL) is a treatment modality that intends to halt progression of keratoconus. This study investigates the efficacy av CXL in stabilizing the cornea in keratoconus by means of a randomized controlled clinical trial.
Participants are eligible for inclusion if progressive keratoconus is confirmed and the inclusion criteria are met. Follow-up after inclusion is at 1 week (treatment group), 1, 3, 6 and 12 months. Pre- and post-inclusion examinations include measurement of uncorrected distance visual acuity (UCDVA), best spectacle corrected distance visual acuity (BSCDVA), Scheimpflug-topography and slitlamp examination.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Corneal Collagen Crosslinking | Active Comparator | The keratokonic eye which progresses most is included and randomized. Significant progression is defined in the eligibility criteria section. If randomized to the treatment arm the cornea is treated with collagen crosslinking as described below. |
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| Control group | No Intervention | The keratokonic eye which progresses most is included and randomized to either the treatment group (CXL) or the control group. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Corneal Collagen Crosslinking | Device | Keratoconic corneas that show significant progression as specified in the inclusion criteria section will receive one single treatment with CXL if randomized to the treatment arm. A treatment protocol based on 30 minutes dropping with riboflavin/dextran solution and 10 minutes UV-illumination treatment will be used. |
| Measure | Description | Time Frame |
|---|---|---|
| Kmax | Kmax is defined as the steepest radius of curvature of the anterior corneal surface. It is measured by Scheimpflug-topography (Pentacam, Oculus Inc.). An increase of less than 1 diopter (D) from baseline at 12 months is defined as non-progression. | 12 months |
| Measure | Description | Time Frame |
|---|---|---|
| Sim-K-astigmatism | Sim-K-astigmatism (Sim-K-ast) is defined as the absolute amount of anterior corneal astigmatism related to the Sim-Ks as measured by Scheimpflug-topography (Pentacam, Oculus Inc.). An increase of less than 1 D from baseline at 12 months is defined as non progression. | 12 months |
| MRSE |
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Inclusion Criteria:
Keratoconus diagnosis determined clinically and topographically (KISA%- index)
Significant progression is defined as change (increase) of Kmax by at least
1D from baseline at 6 months and/or change (increase) of Sim-K-ast by at least 1D from baseline at 6 months. Kmax is defined as the steepest radius of curvature (either the maximum simulated K-reading or the maximum K-reading in the 3-mm zone or the 5-mm zone) of the anterior corneal surface that progressed the most during 6 months observation
Ability to stop contact lens (rigid and soft) wear at least two weeks prior to next exam
Signed written informed consent
Exclusion Criteria:
Relative exclusion criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Madeleine Zetterberg, MD, PhD | Sahlgrenska University Hospital | Study Chair |
| Margareta Claesson, MD, PhD | Sahlgrenska University Hospital | Study Director |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Department of Ophthalmology, Sahlgrenska University Hospital | Mölndal | Västra Götalandsregionen | 43180 | Sweden |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 21183110 | Background | Hersh PS, Greenstein SA, Fry KL. Corneal collagen crosslinking for keratoconus and corneal ectasia: One-year results. J Cataract Refract Surg. 2011 Jan;37(1):149-60. doi: 10.1016/j.jcrs.2010.07.030. | |
| 21700105 | Background | Greenstein SA, Fry KL, Hersh PS. Corneal topography indices after corneal collagen crosslinking for keratoconus and corneal ectasia: one-year results. J Cataract Refract Surg. 2011 Jul;37(7):1282-90. doi: 10.1016/j.jcrs.2011.01.029. |
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| ID | Term |
|---|---|
| D007640 | Keratoconus |
| ID | Term |
|---|---|
| D003316 | Corneal Diseases |
| D005128 | Eye Diseases |
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| ID | Term |
|---|---|
| D000094504 | Corneal Cross-Linking |
| ID | Term |
|---|---|
| D010778 | Photochemotherapy |
| D003131 | Combined Modality Therapy |
| D013812 | Therapeutics |
| D004358 | Drug Therapy |
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|
Manifest Refractive Spherical Equivalent. The spherical equivalent is calculated by algebraic addition of the spherical power and half the cylindrical power of an eye. An eye with a specific spherical equivalent power has the closest overall effect to a given toric lens. A decrease of less than 0.5 D from baseline at 12 months is defined as non-progression. |
| 12 months |
| UCDVA | UCDVA is defined as the uncorrected distance visual acuity measured with an Early Treatment of Diabetic Retinopathy Study (ETDRS)-chart and expressed in numbers of letters. A decrease of less than 5 letters (one line) from baseline at 12 months is defined as stable BCDVA. | 12 months |
| BSCDVA | BSCDVA is defined as the the best spectacle corrected distance visual acuity measured with an ETDRS-chart and expressed in numbers of letters. A decrease of less than 5 letters (one line) from baseline at 12 months is defined as stable BCDVA. | 12 months |
| 12719068 | Background | Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003 May;135(5):620-7. doi: 10.1016/s0002-9394(02)02220-1. |
| 24393351 | Background | Wittig-Silva C, Chan E, Islam FM, Wu T, Whiting M, Snibson GR. A randomized, controlled trial of corneal collagen cross-linking in progressive keratoconus: three-year results. Ophthalmology. 2014 Apr;121(4):812-21. doi: 10.1016/j.ophtha.2013.10.028. Epub 2014 Jan 6. |
| D010789 |
| Phototherapy |