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Refractive Treatment of Early Keratoconus

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT02613780
Recruitment Status : Unknown
Verified December 2015 by Ottawa Hospital Research Institute.
Recruitment status was:  Not yet recruiting
First Posted : November 25, 2015
Last Update Posted : December 14, 2015
Sponsor:
Collaborator:
Abbott Medical Optics
Information provided by (Responsible Party):
Ottawa Hospital Research Institute

Brief Summary:

Keratoconus is a bilateral, progressive corneal degenerative disorder that often leads to significant visual deterioration over time. Corneal collagen crosslinking with riboflavin (CXL) was developed as a treatment to halt the progression of keratoconus and thus negate the need for corneal transplantation. However, the treatment alone has little impact in terms of improving visual function. Photorefractive keratectomy (PRK) is the application of an excimer laser to treat a patient's refractive error, therefore decreasing the dependence on spectacles or contact lenses for improved vision.

Corneal collagen crosslinking combined with photorefractive keratectomy has been explored to partially correct the refractive error in keratoconic patients, whilst simultaneously stabilizing the corneal changes. Recently, the iDesign® Advanced WaveScan Studio (iDesign system; Abbot Medical Optics; Santa Ana, CA) has been launched as the most advanced high-resolution aberrometer. It is capable of mapping highly aberrated corneas for wavefront-guided laser procedures, and represents an important technological advance in treating corneal disease.

The purpose of this single center, prospective pilot study is to assess the safety and efficacy of combined wavefront-guided PRK and CXL in patients with early keratoconus using the iDesign® aberrometer. Results of this pilot study will be used to provide sample size estimates for an extension of the study, which aims to determine whether sequential or same day procedure leads to better outcomes.


Condition or disease Intervention/treatment Phase
Keratoconus Procedure: Crosslinking Procedure: Photorefractive keratectomy Device: iDesign® Advanced WaveScan Studio Phase 3

Detailed Description:

The purpose of this pilot study is to assess the visual outcomes of combined wavefront-guided PRK and CXL in Krumeich stage 1 and 2 keratoconic eyes. The investigators will be conducting a prospective study at the University of Ottawa Eye Institute. A total of 24 patients will be enrolled in the study divided into two groups:

Group 1: PRK performed12-18 months after CXL; Group 2: PRK performed or on the same day as CXL

Participants will be followed at regular intervals for 1 year and information regarding visual, refractive, keratometric and higher order aberration outcomes will be collected.

The researchers aim to investigate the safety and efficacy of combined wavefront guided PRK and CXL. Results of this pilot study will used to provide estimates for sample size calculation for an extension of the study, which aims to determine whether sequential or same day procedure leads to better outcomes.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 24 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: iDesign Aberrometer for the Refractive Treatment of Early Keratoconus
Study Start Date : January 2016
Estimated Primary Completion Date : January 2017
Estimated Study Completion Date : January 2019

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Active Comparator: Sequential group
Photorefractive keratectomy will be performed 12-18 months after participants had crosslinking
Procedure: Crosslinking
corneal collagen crosslinking with riboflavin

Procedure: Photorefractive keratectomy
Device: iDesign® Advanced WaveScan Studio
Used to map wavefront aberration in planning photorefractive keratectomy

Active Comparator: Simultaneous group
Photorefractive keratectomy and crosslinking will be performed on the same day
Procedure: Crosslinking
corneal collagen crosslinking with riboflavin

Procedure: Photorefractive keratectomy
Device: iDesign® Advanced WaveScan Studio
Used to map wavefront aberration in planning photorefractive keratectomy




Primary Outcome Measures :
  1. Improvement in best-corrected visual acuity at followups [ Time Frame: 1 year ]
    Best-corrected visual acuity (BCVA) will be measured in logMAR. Preoperative BCVA will be compared to BCVA postoperatively and at followups over 1 year using paired t tests.


Secondary Outcome Measures :
  1. Intraoperative and postoperative complications [ Time Frame: 1 year ]
    Number of patients with unexpected complications, as well as the type of complication will be collected over 1 year of followups.



Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

Group 1:

1. Patients with confirmed diagnosis of keratoconus in Krumeich stage 1 or 2 who have received crosslinking 12-18 months prior, with follow up of at least 12 months

Group 2:

  1. Diagnosis of keratoconus confirmed based on clinical examination findings and corneal topography
  2. Evidence of progression of keratoconus occurring over the last 12 months defined as:

    i. An increase of maximum keratometry reading by 1 diopter or more (≥ 1 D), or ii. Evidence of clinical progression

  3. Age between 21 and 60 years
  4. Eyes satisfying all of Krumeich stage 1 or 2 criteria listed below i. Stage 1: eccentric corneal bulging, myopia, and/or astigmatism <5 D and corneal radius ≤48 D, no corneal opacities ii. Stage 2: myopia and/or astigmatism >5 D and <8 D and/or corneal radius ≤53 D, no central opacities, pachymetry ≥400 μm

Exclusion Criteria:

  1. Age less than 21 years, or older than 60 years
  2. Pregnant, or planning to become pregnant, or breastfeeding
  3. Past history of Herpes Simplex Keratitis or corneal surgery (other than crosslinking)
  4. Thin Cornea (<425 microns)
  5. Other corneal disease, corneal scarring
  6. History of chemical burns to the cornea or known healing problems
  7. Known allergy to Riboflavin (vitamin B2)
  8. If patient suffers from nystagmus or any other condition that would render it difficult for the patient to hold a steady gaze
  9. Very advanced corneal ectasia (beyond Krumeich stage 2)
  10. Poor visual potential
  11. Vitamin C supplements within 1 week of the procedure
  12. Lenticular changes (cataracts)
  13. Programmed PRK treatment exceeding 50 microns in tissue depth

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02613780


Contacts
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Contact: Setareh Ziai, MD, FRCSC ziaieye@gmail.com

Sponsors and Collaborators
Ottawa Hospital Research Institute
Abbott Medical Optics
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Responsible Party: Ottawa Hospital Research Institute
ClinicalTrials.gov Identifier: NCT02613780    
Other Study ID Numbers: 20150570-01H
First Posted: November 25, 2015    Key Record Dates
Last Update Posted: December 14, 2015
Last Verified: December 2015
Additional relevant MeSH terms:
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Keratoconus
Corneal Diseases
Eye Diseases