Evaluating Risk Factors of Post-LASIK Ectasia

October 13, 2018 updated by: HMTAbdelmoniem, Assiut University

Risk Assessment for Corneal Ectasia Following Laser in Situ Keratomileusis

Ectasia after refractive surgery is a relatively rare complication which can lead to sight-threatening complications if not detected and treated in time. It is important to continue our quest to improve our methods of identifying absolute and relative risk factors of ectasia following various keratorefractive surgical procedures.

Study Overview

Status

Unknown

Conditions

Detailed Description

Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, refractive lenticule extraction (ReLEx) of intracorneal tissue using only a femtosecond laser, and lately ReLEx smile (SMILE). The term LASIK (Laser in situ keratomileusis) was first used in 1990 by Pallikaris, in which a microkeratome was used to cut a hinged corneal flap, followed by excimer ablation of the stromal bed and flap repositioning . LASIK is known to be a safe refractive surgical procedure, with good refractive efficacy and predictability and is associated with rapid visual recovery with minimal risk of complications.

Most of complications are flap related and include a free cap, a button hole, an incomplete cut, flap striae, interface debris, diffuse lamellar keratitis (DLK), and epithelial ingrowth. Other complications include undercorrection, overcorrection, decentered ablation, irregular ablation, and ectasia.

Corneal ectasia is a sight-threatening complication of laser refractive surgery characterized by progressive steepening and thinning of the cornea.It is defined as progressive stromal thinning and steepening of the cornea, resulting in refractive aberrations and visual deterioration. The incidence of post- LASIK ectasia is estimated to be between 0.04% and 0.6%.Corneal ectasia has been observed to occur as early as 1 week and as late as several years after LASIK.

The main purpose of assessing risk is to determine what group or groups of people present a higher chance to develop post-LASIK ectasia. The development of postoperative ectasia varies between LASIK centers and depends on the screening tools used to screen candidates, the experience and technical skill of the surgeon, and the tools used during the surgery. Risk factors for the development of post-LASIK ectasia include young age, a personal or family history of keratoconus, forme fruste keratoconus (FFKC), high myopia, low-residual stromal bed (RSB), and deep primary keratotomy resulting in a thick flap.

Although several risk factors have been identified for the likelihood of ectasia development after keratorefractive surgeries, some cases have been reported to develop in an enigmatic way, without the prescence of any of these risk factors.

Study Type

Observational

Enrollment (Anticipated)

25

Contacts and Locations

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

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

14 years to 41 years (Adult)

Accepts Healthy Volunteers

N/A

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

patients presented with post-LASIK corneal ectasia

Description

Inclusion Criteria:

  • All subjects presented with ectasia following LASIK

Exclusion Criteria:

  • Any associated ocular pathology.
  • Any previous ocular surgeries other than LASIK.
  • Corneal opacities.
  • Ocular trauma.

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

  • Observational Models: Other
  • Time Perspectives: Retrospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Post-LASIK Ectasia
Time Frame: 5 minutes
Evaluating back elevation of cornea (in numbers) , corneal curvature (in diopters) , and curvature map (in diopters) using Pentacam oculizer
5 minutes

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Absolute and relative risk factors of ectasia and their cut-off values.
Time Frame: 5 minutes
Degree of refraction error (in diopters) using Autorefractometer , corneal pachymetry (in micrometers) , residual stromal bed (in micrometers) , flap thickness (in micrometers) , ablation depth (in micrometers) using Pentacam oculizer , and time between LASIK and diagnosis of ectasia (in days)
5 minutes

Collaborators and Investigators

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

Sponsor

Assiut University

Investigators

  • Study Chair: Khaled A. Mohamed, Lecturer, Assiut 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 (Anticipated)

December 10, 2018

Primary Completion (Anticipated)

December 10, 2019

Study Completion (Anticipated)

August 10, 2020

Study Registration Dates

First Submitted

October 10, 2018

First Submitted That Met QC Criteria

October 13, 2018

First Posted (Actual)

October 17, 2018

Study Record Updates

Last Update Posted (Actual)

October 17, 2018

Last Update Submitted That Met QC Criteria

October 13, 2018

Last Verified

October 1, 2018

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RFinCE

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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