TE-oPTK for corneal irregularities
Research type
Research Study
Full title
Trans-epithelial optical phototherapeutic keratectomy (TE-oPTK) for the treatment of irregularly irregular astigmatism
IRAS ID
260808
Contact name
Dan Reinstein
Contact email
Sponsor organisation
London Vision Clinic
Clinicaltrials.gov Identifier
Duration of Study in the UK
2 years, 7 months, 31 days
Research summary
Complications after laser eye surgery can often result in the front surface of the eye (the cornea) becoming irregular, which causes visual symptoms such as halos, glare, starbursts, double vision, and reduced contrast sensitivity. For the past 20 years, corneal irregularities have been treated using wavefront-guided ablation, topography-guided ablation or trans-epithelial phototherapeutic keratectomy (TE-PTK). Topography-guided ablation is the most effective treatment for certain types of irregularity and works by using a laser to remove tissue from the cornea in a pattern derived from a topography scan (a measurement of the shape and curvature of the front of the eye) designed to make the corneal surface more regular.
However, topography-guided ablation is less effective for other types of irregularity. In these cases, the corneal epithelium (the layer of skin on the surface of the cornea) has changed in thickness to partly hide the irregularity on the body of the cornea under the epithelium (the stroma). The epithelium does this by becoming thinner over peaks and thickening over troughs in the stroma. Therefore, the topography measurement can only detect the part of the irregularity that has not been hidden by the epithelium, hence reducing its effectiveness. The preferred treatment option is TE-PTK; the laser treatment is applied onto and through the epithelium, breaking through to the stroma where the epithelium is thinnest, and therefore removing tissue from the peaks on the stroma resulting in a more regular surface.
The main weakness of TE-PTK is that it may unpredictably change the refraction to become more short-sighted or more long-sighted or change the astigmatism. To improve this, we have developed the Epimaster software that simulates a TE-PTK treatment and predicts the change in refraction.
The aim of the study is to validate the refractive prediction produced by the Epimaster software by comparing this to the achieved result in the patients treated. The treatment received by the patient will be the same as has been used routinely for the past 20 years.
REC name
London - Stanmore Research Ethics Committee
REC reference
19/LO/0513
Date of REC Opinion
9 Aug 2019
REC opinion
Further Information Favourable Opinion