Scheimpflug Versus Placido-disc System in Evaluation of Corneal Higher-Order Aberrations

February 24, 2024 updated by: Naglaa Mostafa Abdelhafez Abdelmohsen, Assiut University

Scheimpflug Versus Placido-disc System in Evaluation of Corneal Higher-Order Aberrations Before and After LASIK

Aim of work:

To assess the agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (Oculus Pentacam ) regard measuring corneal higher order aberrations before and after LASIK.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Higher-order aberrations (HOAs) are small optical irregularities of the eye, which can have an impact on the quality of the retinal image. In contrast to lower order aberrations, these errors cannot be corrected with regular spectacles and most contact lenses. Additionally, HOAs are responsible for an array of visual symptoms including dysphotopsia, glare, as well as a reduction in contrast sensitivity. The cornea accounts for approximately 90% of ocular aberrations.Advances and breakthroughs in wavefront aberration measurement technology can help clinicians to better understand and manage corneal higher-order aberrations (HOAs), especially for the preoperative planning of corneal refractive surgery and cataract surgery.A recent study has shown that corneal HOAs can be a sensitive parameter to differentiate early keratoconus from normal eyes. Furthermore, corneal aberrations have been widely used to evaluate dry eye and orthokeratology.LASIK surgery is widely used in the correction of refractive errors It is well known that LASIK surgery induces high-order aberrations (HOA) .The main eye element involved in the generation of such aberrations is the first corneal surface. Currently, devices based on Placido-disc, Hartmann- Shack, ray tracing, or Scheimpflug are routinely used in clinical aberration measurement. Of which Pentacam is one of common instruments that can only measure corneal aberration (including anterior and posterior corneal surface) based on Scheimpflug technology. Also Allegro Topolyzer is a Placido-based topographer that can measure anterior corneal higher order aberrations (HOAs). A better understanding of the agreement of device measurements can provide clinicians with useful information for measuring, correcting, and monitoring aberrations around refractive and cataract surgery. Investigators , therefore, aimed to study the agreement between the two instruments in anterior corneal aberration measurement.

Study Type

Observational

Enrollment (Estimated)

36

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 Locations

  • Egypt
      • Assiut, Egypt
        • Naglaa Moustafa

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

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients who will undergo LASIK

Description

Inclusion Criteria:

  • Patients with refractive errors from +6 diopters to -8 diopters sphere and up to -6diopters cylinder.

Exclusion Criteria:

  • Patients with systemic diseases such as diabetes.
  • keratoconus or keratoconus suspect, amblyopic eyes.
  • Patients with best corrected visual acuity (BCVA) not achieving 20/25.
  • glucoma
  • Previous ocular surgeries or 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (pentacam)
Time Frame: Before LASIK and 3 months after LASIK
Agreement between placido-based topographer (wavelight allegro topolyzer vario) and scheimpflug -based (pentacam) regard measuring corneal high order aberrations before and after LASIK.
Before LASIK and 3 months after LASIK

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in high order aberrations after LASIK.
Time Frame: Before LASIK and 3 months after LASIK
Changes in high order aberrations after LASIK using pentacam and topolyzer
Before LASIK and 3 months after LASIK

Collaborators and Investigators

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

Sponsor

Assiut University

Investigators

  • Study Director: Tarek A Ali, Professor, Assiut University
  • Study Director: Khaled A Mohamed, Assistant prof, Assiut University
  • Study Director: Islam M Goda, 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 (Estimated)

July 1, 2024

Primary Completion (Estimated)

July 1, 2026

Study Completion (Estimated)

February 1, 2027

Study Registration Dates

First Submitted

February 19, 2024

First Submitted That Met QC Criteria

February 19, 2024

First Posted (Actual)

February 26, 2024

Study Record Updates

Last Update Posted (Actual)

February 28, 2024

Last Update Submitted That Met QC Criteria

February 24, 2024

Last Verified

February 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Corneal HOA

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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