NCT05748847

Brief Summary

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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
74

participants targeted

Target at P50-P75 for not_applicable

Timeline
Completed

Started Jun 2019

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

June 1, 2019

Completed
3.7 years until next milestone

First Submitted

Initial submission to the registry

February 19, 2023

Completed
10 days until next milestone

First Posted

Study publicly available on registry

March 1, 2023

Completed
2 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

April 15, 2023

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

April 15, 2023

Completed
Last Updated

October 31, 2024

Status Verified

October 1, 2024

Enrollment Period

3.9 years

First QC Date

February 19, 2023

Last Update Submit

October 29, 2024

Conditions

Keratoconus

Keywords

KeratoconusFemtosecond laser-assisted ICRSCentral keratoconusKeraRing

Outcome Measures

Primary Outcomes (5)

  • Complications

    Postoperative complications following intrastromal corneal ring segment implantation.

    12 months

  • Postoperative keratometry

    Postoperative keratometry as measured by Scheimpflug imaging Pentacam

    12 months

  • Postoperative Refraction

    Spherical equivalent refraction measured by Topcon Auto-Keratorefractometer

    12 months

  • Corrected distance visual acuity (CDVA)

    Corrected distance visual acuity measurement using Snellen's Acuity Chart expressed as logMAR notation

    12 months

  • Uncorrected distance visual acuity (UDVA)

    Uncorrected distance visual acuity measurement using Snellen's Acuity Chart expressed as logMAR notation

    12 months

Study Arms (2)

Pocket ICRS

ACTIVE COMPARATOR

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)

Tunnel ICRS

ACTIVE COMPARATOR

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)

Interventions

Intrastromal corneal ring segment implantation (Pocket)PROCEDURE

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.

Pocket ICRS
Intrastromal corneal ring segment implantation (Tunnel)PROCEDURE

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.

Tunnel ICRS

Eligibility Criteria

Age18 Years - 35 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

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

You may not qualify if:

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

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Tiba Eye Center

Asyut, Asyut Governorate, 71516, Egypt

Location

Related Publications (2)

  • Izquierdo L Jr, Rodriguez AM, Sarquis RA, Altamirano D, Henriquez MA. Intracorneal circular ring implant with femtosecond laser: Pocket versus tunnel. Eur J Ophthalmol. 2022 Jan;32(1):176-182. doi: 10.1177/1120672121994729. Epub 2021 Feb 12.

    PMID: 33579160BACKGROUND

  • Abdel-Radi M, Anwar M, Mostafa MM. Complications and Outcomes of Femtosecond Laser-Assisted Corneal Pocket Implantation of 360-Degree MyoRing(R) Versus Corneal Tunnel Implantation of 340-Degree Keraring(R) for the Management of Central Keratoconus. Curr Eye Res. 2025 Nov 20:1-9. doi: 10.1080/02713683.2025.2587890. Online ahead of print.

    PMID: 41263332DERIVED

MeSH Terms

Conditions

Keratoconus

Condition Hierarchy (Ancestors)

Corneal DiseasesEye Diseases

Study Officials

  • Mahmoud Abdel-Radi, MD

    Assiut University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
SINGLE
Who Masked
PARTICIPANT
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Principal Investigator

Study Record Dates

First Submitted

February 19, 2023

First Posted

March 1, 2023

Study Start

June 1, 2019

Primary Completion

April 15, 2023

Study Completion

April 15, 2023

Last Updated

October 31, 2024

Record last verified: 2024-10

Data Sharing

IPD Sharing
Will not share

Locations

EG(1)