Ectasia, Keratoconus
Conditions
Keywords
Keratoconus, Ectasia, UVA light, riboflavin, post-LASIK, irregular astigmatism
Brief summary
The purpose of the study is to see if brighter lights will allow for shortening of the treatment time required to stabilize the eyes of patients with keratoconus or a bulging cornea. The investigators will be comparing the therapeutic effects of two different higher brightnesses of ultra violet light on a riboflavin treated eye. One light will be twice as bright as the other and the exposure time of these brighter lights to deliver equivalent energy to the cornea will be reduced from the standard 30 minutes to 10 and 5 minutes. Riboflavin is vitamin B2 and the investigators are trying to determine if an identical clinical effect can be achieved the brighter treatment lights are used for shorter times. The investigators will also monitor the clinical effect and the status of the cornea to see if additional risks are associated with the brighter light.
Interventions
DEVICEUVA Light with irradiance exposure of 9 mW/cm2
The device's light emitting diode (LED) is used to deliver a metered dose of Ultraviolet A (UVA) light to a targeted treatment area for illuminating the cornea during corneal collagen cross-linking. The aperture setting will be set at 10 mm, and the eye will be irradiated for 10 minutes for the high irradiance exposure of 9 milliwatts (mW)/cm2. During the exposure, instillation of riboflavin will continue (1 drop every 3 minutes).
The speculum is removed and one (1) drop of Riboflavin 0.1% ophthalmic solution will be instilled topically in the eye every 3 minutes for 30 minutes. At the end of the 30 minute riboflavin pre-treatment period, the eye will be examined to assure the presence of a yellow flare in the anterior chamber, indicating riboflavin saturation of the corneal tissue. If the yellow flare is not detected, riboflavin will continue to be instilled until the presence of the yellow flare in the anterior chamber is confirmed. During UVA irradiation, instillation of riboflavin will be continued every 3 minutes. For a 30-minute pre-treatment and 30-minute irradiation, the total dose of riboflavin solution is approximately 32 drops, or 1.6 ml (1 drop = 0.05 ml; 1.6 mL = 1.6 mg riboflavin).
Sponsors
Stephen Trokel
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
30 patients will be treated at 9 mw/cm2.
Eligibility
Sex/Gender
ALL
Age
16 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Subjects who have one or both eyes that meet two of the following criteria will be considered candidates for this study: 1. 16 years of age or older 2. Having a diagnosis of progressive keratoconus or pellucid marginal degeneration. 1. Characteristic pattern of deformity as analyzed by the Pentacam map. 2. Minimal thickness of 350 microns 3. The ability to sign a written informed consent 4. States a willingness and ability to comply with schedule for follow-up visits 5. Subject willing to remove contact lenses prior to evaluation and treatment Inclusion criteria for ectasia 1. History of having undergone a keratorefractive procedure and show: 1. Steepening by Pentacam study 2. Thinning of cornea 3. Shift in the position of thinnest portion of cornea 4. Unstable refraction with increasing myopia and astigmatism 5. Development of irregular astigmatism 2. At least two of the above criteria must be present.
Exclusion criteria
Subjects meeting any of the following criteria will be excluded from this study: Subjects meeting any of the following criteria will be excluded from this protocol: 1. Eyes classified as either normal or atypical normal, 2. Corneal pachymetry ≤ 350 microns at the thinnest point in treatment zone measured by Pentacam. 3. A history of delayed epithelial healing. 4. Pregnancy (including plan to become pregnant) or lactation during the course of the study 5. A known sensitivity to study medications 6. Patients with nystagmus or any other condition that is severe enough to prevent steady gaze during the treatment 7. Inability to cooperate with diagnostic tests. 8. Patients with a current condition that, in the investigator's opinion, would interfere with or prolong epithelial healing. 9. Patients who are unable to remain supine and tolerate a lid speculum.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Total Optical Aberrations of the Cornea following Cross-Linking | Baseline to 6 months | Assessment of changes in corneal curvature, as analyzed using a Pentacam Scheimpflug Analyzer will be used in all patients. This allows measurement of corneal thickness, maximum and minimum curvatures and aberration analysis of the cornea as an optical element. The most significant objective measure of change is the total Higher Order Aberrations of the cornea and the Kmax, or steepest curvature of the cornea. Analysis of corneal curvature is directly related to improvement in the corneal shape which is directly related to visual function. |
Countries
United States
Outcome results
None listed