Pocket Versus Tunnel ICRS for Treatment of Keratoconus

October 29, 2024 updated by: Mahmoud Abdel-Radi, Assiut University

Pocket Versus Tunnel Intrastromal Corneal Ring Segment Implantation (KeraRing) for the Management of Central Keratoconus

Keratoconus is a corneal degenerative disease associated with loss of best-corrected visual acuity. The use of intrastromal corneal ring segment implants is indicated to regularize the cornea and to reduce aberrations.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Keratoconus is a corneal degenerative disease characterized by corneal thinning and subsequent development of irregular astigmatism, diminution of vision and loss of best-corrected visual acuity.

Management of keratoconus includes halting disease progression through a corneal strengthening procedure called corneal collagen cross-linking (CXL) which usually results in stabilizing the condition but with no improvement in visual acuity or quality. Intrastromal corneal ring segment (ICRS) implantation is a well-established procedure for the management of moderate keratoconus with a corneal flattening effect that is associated with improvement of visual acuity and reduction of optical aberrations.

The aim of the study is to evaluate and compare the visual, refractive and topographic outcomes of two different femtosecond laser assisted surgical techniques to create a corneal stromal pocket or a tunnel for implantation of ICRS for the management of central keratoconus

Study Type

Interventional

Enrollment (Actual)

74

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
      • Assiut, Egypt, 71516
        • TIBA Eye Center

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

Yes

Description

Inclusion Criteria:

  1. Patients with progressive keratoconus with maximum keratometry (Kmax) between 50-65 diopters
  2. Central keratoconus (Keratoconus with steepest corneal point within the central 3 mm zone).
  3. Clear corneal with a minimum pachymetry of 400 μm.

Exclusion Criteria:

  1. Corneal scars
  2. Patients with advanced keratoconus with Kmax > 65 diopters.
  3. Non-central keratoconus (para-central or peripheral keratoconus with steepest corneal point outside the central 3 mm zone).
  4. Previous corneal cross-linking and/or ocular surgery.
  5. Systemic diseases such as diabetes mellitus and autoimmune diseases

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Pocket ICRS
Patients in this group underwent 360-degree MyoRing implantation through a femtosecond laser-assisted corneal pocket creation for the management of their central keratoconus.
Procedure: Intrastromal corneal ring segment implantation (Pocket)

Patients in this group are planned to undergo ICRS implantation through a femtosecond laser-assisted pocket creation.

The device creates an intrastromal corneal pocket of 8-mm diameter and a depth of nearly 80% of the corneal thickness at the thinnest location with a superior tunnel incision at 90° of 5-mm width.
Active Comparator: Tunnel ICRS
Patients in this group are underwent 340-degree KeraRing implantation through a femtosecond laser-assisted corneal tunnel creation for the management of their central keratoconus.
Procedure: Intrastromal corneal ring segment implantation (Tunnel)

Patients in this group are planned to undergo ICRS implantation through a femtosecond laser-assisted tunnel creation.

The device creates an intrastromal tunnel with a depth of nearly 80% of the corneal thickness at the site of implantation. The tunnel inner and outer diameters are at 5 and 6 mm from the corneal center, respectively with the incision located at the steepest keratometry axis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Complications
Time Frame: 12 months
Postoperative complications following intrastromal corneal ring segment implantation.
12 months
Postoperative keratometry
Time Frame: 12 months
Postoperative keratometry as measured by Scheimpflug imaging Pentacam
12 months
Postoperative Refraction
Time Frame: 12 months
Spherical equivalent refraction measured by Topcon Auto-Keratorefractometer
12 months
Corrected distance visual acuity (CDVA)
Time Frame: 12 months
Corrected distance visual acuity measurement using Snellen's Acuity Chart expressed as logMAR notation
12 months
Uncorrected distance visual acuity (UDVA)
Time Frame: 12 months
Uncorrected distance visual acuity measurement using Snellen's Acuity Chart expressed as logMAR notation
12 months

Collaborators and Investigators

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

Sponsor

Assiut University

Investigators

  • Principal Investigator: Mahmoud Abdel-Radi, MD, 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 (Actual)

June 1, 2019

Primary Completion (Actual)

April 15, 2023

Study Completion (Actual)

April 15, 2023

Study Registration Dates

First Submitted

February 19, 2023

First Submitted That Met QC Criteria

February 19, 2023

First Posted (Actual)

March 1, 2023

Study Record Updates

Last Update Posted (Actual)

October 31, 2024

Last Update Submitted That Met QC Criteria

October 29, 2024

Last Verified

October 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PVTICRS

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

product manufactured in and exported from the U.S.

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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