To Study the Effects of Refractive Surgery on OCT Measurements in the Eye

Study Overview
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Brief Summary
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Corrective eye surgeries, such as Lasik, are widely used to correct focusing problems such as myopia, or nearsightedness. Often these patients develop other conditions like myopic maculopathy or glaucoma which require monitoring with optical coherence tomography (OCT). Since OCT is a light-based test and changes the refractive status of the eye (in the cornea or the lens), it can potentially affect the results of the OCT measurements but has not been sufficiently studied. This pilot study aims at studying the potential change in OCT parameters in the eye after undergoing such surgery.

Detailed Description
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Refractive surgeries are widely used in patients with ametropia. Refractive surgery is most commonly performed in patients with myopia. These patients often have a predilection for developing other conditions in the posterior segment of the eye, like myopic maculopathy or glaucoma which require monitoring with optical coherence tomography (OCT). Since OCT is a light-based test and changes in the refractive status of the eye (in the cornea or the lens) can potentially affect the results of the OCT measurements. Literature review reveals that the effect of significant changes in refractive power of the eye on the parameters of optical coherence tomography (OCT) has not been sufficiently studied. Some authors simulated the effect of refractive surgery using a contact lens but had diverging results. This prospective pilot study aims at studying the potential change in OCT parameters in the eye after undergoing refractive surgery.

Official Title
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To Study the Effects of Refractive Surgery on Optical Coherence Tomography (OCT) Measurements in the Eye: A Pilot Study

Conditions
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Optical Coherence Tomography, Refractive Errors, Myopia

Intervention / Treatment
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* Diagnostic Test: Optical coherence tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing refractive surgery For patients undergoing bilateral eye surgery, the one with higher degree of ametropia will be included. Exclusion Criteria: Astigmatism more than 3 Diopters Visual acuity worse than 20/25 Patients with unstable visual fixation Severe Dry Eye

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Ocular parameters<br>Patients aged 19 years or more who are scheduled to undergo refractive surgery will be included in the study. OCT will be performed at baseline (before surgery), 1 day after surgery and 1 week after surgery. Each patient will be tested 3 times. | Diagnostic Test: Optical coherence tomography<br>* Posterior segment OCT (a non-contact procedure performed over one minute) is additionally performed for patients participating in this study. Proportion of change in measurements in microns will be analyzed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Macular thickness | Proportion of Change in thickness of retina and its layers measured in microns | 1 day after refractive procedure | 
| Macular thickness | Proportion of Change in thickness of retina and its layers measured in microns | 1 week after refractive procedure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Choroidal thickness | Proportion of Change in thickness of choroid and its layers measured in microns | 1 day after refractive procedure | 
| Choroidal thickness | Proportion of Change in thickness of choroid and its layers measured in microns | 1 week after refractive procedure | 
| visual acuity | Proportion of Change in clarity of vision, measured in logarithm of Minimal Angle of Resolution (logMAR) units | 1 day after refractive procedure | 
| visual acuity | Proportion of Change in clarity of vision, measured in logarithm of Minimal Angle of Resolution (logMAR) units | 1 week after refractive procedure | 
| central corneal thickness | Proportion of Change in thickness of cornea measured in microns | 1 day after refractive procedure | 
| central corneal thickness | Proportion of Change in thickness of cornea measured in microns | 1 week after refractive procedure | 
| anterior chamber depth | Proportion of Change in depth of anterior chamber of the eye measured in microns | 1 day after refractive procedure | 
| anterior chamber depth | Proportion of Change in depth of anterior chamber of the eye measured in microns | 1 week after refractive procedure | 
| keratometry | Proportion of Change in corneal curvature measured in diopters | 1 day after refractive procedure | 
| keratometry | Proportion of Change in corneal curvature measured in diopters | 1 week after refractive procedure |