Astigmatism, Myopia
Conditions
Keywords
Myopia, Astigmatism, Corneal haze, Trans Photorefractive Keratectomy, Alcohol Photorefractive Keratectomy
Brief summary
surgical correction of ametropia. A number of improvements have been introduced to overcome the side effects and complications such as corneal haze, epithelial irregularities induced by wound healing, pain and delayed visual acuity recovery associated with PRK surgery. During traditional PRK, the corneal epithelium is mechanically debrided before stromal ablation is performed. Alcohol PRK is frequently used as an alternative to mechanical epithelial debridement and is considered simpler and faster. Transepithelial PRK (TransPRK) is a new method in which the corneal epithelium is photoablated by the laser in one step using a specific ablation profile. This study attempts to establish a means of quantitatively and objectively measuring corneal haze, using patented software based on optical coherence tomography (OCT) of the cornea. This will confirm or refute the hypothesis of a lower occurrence of corneal haze after TransPRK (experimental group) versus PRK with alcohol (control group). Each patient will have one eye randomised to one of the two groups being compared.
Interventions
PROCEDURETransPRK
A Merocel sponge is soaked in a saline solution to expand before being gently applied to the corneal surface in three gestures similar to painting. This standardised procedure avoids inhomogeneous wetting of the cornea, which would result in uneven ablation. The laser ablation is then performed.
PROCEDUREAlcohol PRK
A ring is placed in the centre of the cornea and filled with 20% alcohol. After 20 seconds of exposure, the alcohol is absorbed with a small sponge and the corneal epithelium is debrided with a polyvinyl alcohol expanding sponge (Merocel, Medtronic). The entire cornea is rinsed with balanced salt solution and the epithelium is peeled away from the corneal stroma. The corneal bed is then dried with a small sponge and laser ablation is performed.
Sponsors
Fondation Ophtalmologique Adolphe de Rothschild
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Planned Photorefractive Keratectomy in both eyes * Simple myopia or myopic astigmatism, refractive spherical equivalent between -0.50 and -9.0 diopters in both eyes with regular corneal topography
Exclusion criteria
* Only one eye operated on * At least one contraindication to refractive surgery, namely : keratoconus, minimum corneal thickness \< 400 µm, severe dry syndrome, progressive corneal infection * Personal history of corneal surgery * Personal history of ocular pathology other than simple myopia or myopic astigmatism * Pregnant or breastfeeding woman
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Corneal haze assessed with the the software analysing the corneal OCT images | 1 month after refractive surgery | Corneal haze assessed by the intensity of the luminosity of the whole cornea (expressed as a percentage) evaluated by the software analysing the corneal OCT images. |
Countries
France
Outcome results
None listed