KeratoconusNCT05748847

Pocket Versus Tunnel ICRS for Treatment of Keratoconus

A study testing Intrastromal corneal ring segment implantation (Pocket) and Intrastromal corneal ring segment implantation (Tunnel) in people with Keratoconus, run by Assiut University at 1 site in Egypt.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial 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. Read more about this study

Who is it for?: Ages 18 to 35 yearsHealthy volunteers can take part
Conditions the study is for: Keratoconus
What is being tested?: Intrastromal corneal ring segment implantation (Pocket) and Intrastromal corneal ring segment implantation (Tunnel)
Type of treatment: Surgery or procedure
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 74 participants
Where: 1 siteEgypt
Study dates: 1 Jun 2019to 15 Apr 2023
Phase: Interventional
Are there results?: None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 35 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

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.

Who cannot join

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

Trial locations and contacts

1 site in 1 country.

Egypt1 site

Tiba Eye Center
Asyut, Asyut Governorate, 71516

Other trials in Egypt

About this study

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

Read the 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

Conditions: Keratoconus
Being tested: Intrastromal corneal ring segment implantation (Pocket), Intrastromal corneal ring segment implantation (Tunnel)
Keywords: Keratoconus, Femtosecond laser-assisted ICRS, Central keratoconus, KeraRing
Medical subject headings: Keratoconus

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Intrastromal corneal ring segment implantation (Pocket)Procedure or surgery
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.
Intrastromal corneal ring segment implantation (Tunnel)Procedure or surgery
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.

Study groups in NCT05748847
Study group	Role	What they receive
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. Receives: 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. Receives: Procedure: Intrastromal corneal ring segment implantation (Tunnel)

What is being measured

The primary outcome is the main question the study is designed to answer.

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

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

1 Jun 201915 Apr 2023

First posted1 Mar 2023
Study start1 Jun 2019
Primary completion15 Apr 2023
Study completion15 Apr 2023

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Publications (2)Papers the sponsor has linked to this study.
Other trials for KeratoconusStudies of the same condition, open and under way.
More trials run by Assiut UniversityThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind
Who is masked: Participant
Enrolment: 74 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05748847
Sponsor's protocol ID: PVTICRS
Status last verified: Oct 2024
First submitted: 19 Feb 2023
Last updated: 31 Oct 2024
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

Publications

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.
PubMed 33579160
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. 2026 Mar;51(3):231-239. doi: 10.1080/02713683.2025.2587890. Epub 2025 Nov 20.
PubMed 41263332

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Keratoconus trials

Study at a glance

From the registry record, last updated by the sponsor on 31 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Pocket Versus Tunnel Intrastromal Corneal Ring Segment Implantation (KeraRing) for the Management of Central Keratoconus
ClinicalTrials.gov ID: NCT05748847
Acronym / sponsor ID: PVTICRS
Conditions: Keratoconus
Keywords: Keratoconus, Femtosecond laser-assisted ICRS, Central keratoconus, KeraRing
Study type: Interventional
Recruitment status: Completed
Enrolment: 74 participants (actual)
Lead sponsor: Assiut UniversityUniversity, hospital or other
Study start: 1 Jun 2019 (actual)
Primary completion: 15 Apr 2023 (actual)
Study completion: 15 Apr 2023 (actual)
First posted: 1 Mar 2023 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

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.

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind (participant)
Number of arms: 2

Arm	Type	Receives
Pocket ICRS	Active comparator	Procedure: Intrastromal corneal ring segment implantation (Pocket)Patients in this group underwent 360-degree MyoRing implantation through a femtosecond laser-assisted corneal pocket creation for the management of their central keratoconus.
Tunnel ICRS	Active comparator	Procedure: Intrastromal corneal ring segment implantation (Tunnel)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.

Who may qualify

Ages: 18 to 35 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (3 listed)

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.

Key exclusion criteria (5 listed)

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

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
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.	Procedure or surgery	Pocket ICRS
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.	Procedure or surgery	Tunnel ICRS

Primary outcome

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

Results and safety

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 31 Oct 2024.
Results publication: PubMed 33579160Izquierdo 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.
Derived from this study: PubMed 41263332Abdel-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. 2026 Mar;51(3):231-239. doi: 10.1080/02713683.2025.2587890. Epub 2025 Nov 20.
Individual participant dataSharing planned: No

Related trials for Keratoconus

RecruitingObservational study
UNITY DX Cornea Study
Tomography
Not yet recruiting
Performance Evaluation of the OCUTOP Hand-held Corneal Topographer
Corneal Topography, Dry Eye Syndromes
Recruiting
Proof-of-Concept for a Novel Optical Aperture Contact Lens in Presbyopia and Keratoconus
Keratoconus, Presbyopia
RecruitingObservational study
A Study to Test the Diagnostic Potential of Brillouin Microscopy for Corneal Ectasia
Keratoconus, Ectasia
Enrolling by invitationObservational study
Corneal Biomechanical Analysis Using Brillouin Microscopy
Keratoconus, Keratoconus, Unstable

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Mahmoud Abdel-Radi, MD principal investigator

Assiut University

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 31 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Complications (time frame: 12 months). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05748847, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Oct 2024.