OCTA Analysis of Macular and Papillary Perfusion After Refractive Surgery in Myopes

July 24, 2020 updated by: Osama Abdelfattah Sorour, Tanta University

Optical Coherence Tomography Angiography Analysis of Macular and Papillary Perfusion After Variable Refractive Surgery Methods in Myopic Patients

Refractive surgery for correction of myopia is very common nowadays. However, various refractive techniques may be associated with increase in the IOP, especially during flap creation. It is assumed that marked intraoperative IOP increase lead to macular and optic disc head circulation compromise. The purpose of this study is to assess the change of macular and papillary perfusion, using optical coherence tomography angiography (OCTA) imaging of the macula and optic disc of myopic patients before and after various refractive surgery methods.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

Myopia is the most prevalent ocular disorder in children worldwide, and one of the major causes of visual deterioration in all age groups. Highest prevalence rates are in East Asian countries (affecting up to 83% of Singaporean teenagers), however, it is very common in all other countries. While mild to moderate myopia usually stabilizes within the third decade, pathological myopia is associated with progressive globe elongation, and development of various macular complications including; foveoschisis, choroidal neovascularization (CNV), myopic macular hole, and myopic vitreomacular traction (VMT).

Refractive surgery has become popular for correcting ametropia including myopia. Most commonly used refractive procedures include corneal refractive surgeries especially laser in-situ keratomileusis (LASIK), and Photorefractive keratectomy (PRK), Phakic Intraocular Lenses (Phakic IOLs) and refractive lens exchange.

In LASIK, the creation of a corneal lamellar flap requires placement of a suction ring on the anterior segment of the eye, which transiently elevates the intraocular pressure (IOP) to levels exceeding 65 mmHg. Experimental studies in animal eyes have found that the IOP can increase to between 80 mmHg and 360 mmHg during this vacuum phase and lamellar cut with the microkeratome. Recent advances utilizing the femtosecond laser may serve as an alternative to the mechanical microkeratome, with a low-pressure suction ring. In studies using porcine eyes, the IOP during the suctioning or laser application phase reached a maximum of 135 mmHg using the femtosecond laser, lower than pressures reached with a traditional microkeratome, but for a longer duration of time. Similarly in refractive lens procedures, intraoperative IOP was found to exceed 60 mmHg.

Intraocular pressure elevation during refractive procedures may cause a reduction in the perfusion of the retina and optic nerve head, posterior displacement of the lamina cribrosa, and a decline in ocular perfusion pressure of the posterior ciliary arteries. Although this IOP elevation is temporary, the potential for ischemic or pressure-induced damage to the optic nerve head and the retinal nerve fiber layer exists.

Optical coherence tomography angiography (OCTA) is a recent noninvasive imaging technique that allows for volumetric visualization of eye vasculature. OCTA has shown promise in better elucidating the pathophysiology of several retinal vascular diseases. Swept-source OCTA uses long wavelength ̰ 1,050nm, which can penetrate through deeper layers of the eye and can traverse opacities of media such as cataracts, hemorrhages and vitreous opacities [6]. Optical coherence tomographic angiograms can further be manually or automatically segmented with preprogrammed software to highlight individual layers of the retina, optic nerve head choriocapillaris, and choroid. The user can either analyze en face images extending from the inner limiting membrane to choroid or use automated views to locate a vascular or structural lesion within the retina.

The purpose of this study is to assess the change of macular and papillary perfusion, using optical coherence tomography angiography (OCTA) imaging of the macula and optic disc of myopic patients subject to various refractive surgery methods. We will compare between these methods to evaluate which one is associated with least adverse effect on ocular perfusion. To date no such evaluation has been done using OCTA, because of relatively recent onset of this technology. Traditional imaging methods such as color fundus photography and fluorescein angiography have limited resolution for retinal vasculature that mad such evaluation in the past using these methods not feasible, however, OCTA is very promising for the proper analysis of changes in the ocular perfusion. Results of this study will have significant clinical and practical implications and may change the approach for surgical correction of such patients.

Study Type

Interventional

Enrollment (Anticipated)

100

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Egypt
      • Tanta, Egypt, 31515
        • Recruiting
        • Ophthalmology Department, Faculty of medicine, Tanta Univeristy
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 35 years (ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Age: between 20 - 35 years
  2. Patients: who are seeking and fit for refractive surgery
  3. Spherical equivalent refractive error: between (-2 to -9 D)

Exclusion Criteria:

  1. Maculopathies (hereditary or acquired)
  2. optic nerve head pathologies (tilted disc, drusen, optic disc edema, atrophy, etc.)
  3. optic neuropathies (demyelinating, infectious, ischemic, etc.)
  4. adjusted IOP for central corneal thickness more than 21 mmHg
  5. surgery-induced corneal edema
  6. dense cataracts that can disrupt images
  7. systemic diseases (vasculitis, diabetes mellitus, hypertension, etc.)
  8. any previous ocular surgery,
  9. patients with bad quality images or complicated surgeries will be excluded

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: SCREENING
  • Allocation: NON_RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: SINGLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: LASIK group
Patients will do excimer laser LASIK operation for correction of myopia with flap creation by mechanical keratome
Procedure: Refractive surgery
Myopic patients seeking refractive surgery will be assigned to the study groups to assess the change in myopic and papillary perfusion in these different prodecures
ACTIVE_COMPARATOR: SMILE group
Patients will do Femtosecond laser assisted corneal refractive surgery for correction of myopia
Procedure: Refractive surgery
Myopic patients seeking refractive surgery will be assigned to the study groups to assess the change in myopic and papillary perfusion in these different prodecures
ACTIVE_COMPARATOR: Photorefractive keratectomy group
Patients that will undergo photorefractive keratectomy for correction of myopia
Procedure: Refractive surgery
Myopic patients seeking refractive surgery will be assigned to the study groups to assess the change in myopic and papillary perfusion in these different prodecures
ACTIVE_COMPARATOR: Refractive lens exchange
Include eyes that will undergo refractive lens exchange
Procedure: Refractive surgery
Myopic patients seeking refractive surgery will be assigned to the study groups to assess the change in myopic and papillary perfusion in these different prodecures
NO_INTERVENTION: Control group
Myopic control eyes with no surgical intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Vessel density from enface OCT angiogram
Time Frame: 6 months
VD analysis computes the percentage of area occupied by OCTA detected vasculature in a measured area
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tanta University

Investigators

  • Study Chair: Rauf A gaber, MD, Tanta university

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

March 1, 2020

Primary Completion (ANTICIPATED)

October 1, 2020

Study Completion (ANTICIPATED)

December 1, 2020

Study Registration Dates

First Submitted

June 6, 2020

First Submitted That Met QC Criteria

June 6, 2020

First Posted (ACTUAL)

June 9, 2020

Study Record Updates

Last Update Posted (ACTUAL)

July 28, 2020

Last Update Submitted That Met QC Criteria

July 24, 2020

Last Verified

July 1, 2020

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 33553/12/19

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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