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

Status

Indicates the current recruitment status or the expanded access status.
Unknown

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

Study Contact

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Study Contact Backup

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tanta University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2020

Primary Completion (ANTICIPATED)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 1, 2020

Study Completion (ANTICIPATED)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 6, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 6, 2020

First Posted (ACTUAL)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 9, 2020

Study Record Updates

Last Update Posted (ACTUAL)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 28, 2020

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 24, 2020

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2020

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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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