Keratoconus
Conditions
Keywords
Keratoconus (KCN), Optical Coherence Tomography (OCT), Collagen Cross-linking (CXL)
Brief summary
Optical Coherence Tomography (OCT) devices are non-contact instruments that can measure the depth of scars, other causes of cloudiness of the cornea, and degree of corneal thinning in patients with keratoconus. Laser Custom Corneal Collagen Cross-linking (CXL) significantly decreases corneal aberrations and improves vision. This study will use OCT-guided setting for the lasers used in the corneal smoothing portion of the laser custom CXL procedure to assess the affect on visual outcomes.
Detailed description
In the U.S., CXL and topography-guided laser ablation were approved independently, but not together. Another variation in technique involves the use of mitomycin-C (MMC), which is effective in reducing corneal haze after the laser surface ablation. Use of MMC during the laser custom CXL was associated with better outcomes, but in separate trials that could not be directly compared. This study will use OCT measurements to evaluate the magnitudes of direct and indirect laser actions after the procedure.
Interventions
PROCEDURELaser Custom Corneal Collagen Cross-Linking
Preoperative measurements from the OCT are used to assist the calculation in deciding the laser depth settings for smoothing the anterior corneal surface and removing any present opacities. The surgeon uses the OCT data to plan treatment parameters while preserving at least 360 microns of residual corneal stroma using a phototherapeutic keratectomy procedure. After the laser procedure, adjunctive MMC or saline solution will be applied to the cornea in accordance with the group to which the treated eye is randomized. The CXL procedure is then performed following the FDA-approved CXL regimen by Avedro, Inc.
Sponsors
National Eye Institute (NEI)
Oregon Health and Science University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Diagnosis of keratoconus * Minimum corneal thickness of 410 microns
Exclusion criteria
* Inability to maintain fixation for OCT imaging * Inability to commit to required study visits * Inability to give informed consent * Eyes with concurrent retinal diseases, glaucoma, or other eye conditions that may limit the visual outcome after surgery * Mature cataracts if found to limit visual potential to worse than 20/40
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Improvement in best spectacle-corrected visual acuity after laser custom CXL | 6 months after the CXL procedure | The primary goal of the trial is to determine the extent of visual improvement after laser custom CXL compared to preoperative measurements. Vision will be checked at various time points, but the primary time point will be 6-months post-procedure. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Determine CXL demarcation line depth | 1 month after the CXL procedure | The study will use OCT imaging to measure the CXL demarcation line inside the entire optical zone. The demarcation line indicates the portion of corneal stroma being cross-linked. This helps determine to what extent the cornea is being strengthened. |
Countries
United States
Contacts
Primary ContactDenzil Romfh, OD
Backup ContactHumberto Martinez, COT
Outcome results
None listed