Pocket Versus Tunnel ICRS for Treatment of Keratoconus

• Sponsor: Assiut University (Other)
• Overall Status: Active, not recruiting
• CT.gov ID: NCT05748847
• Collaborator: (none)
• Enrollment: 62
• Location: 1
• Arms: 2
• Anticipated Duration (Months): 46
• Patients Per Site Per Month: 1.3

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Keratoconus	Procedure: Intrastromal corneal ring segment implantation (Pocket); Procedure: Intrastromal corneal ring segment implantation (Tunnel)	N/A

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 Design

• Study Type: Interventional
• Actual Enrollment: 62 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Pocket Versus Tunnel Intrastromal Corneal Ring Segment Implantation (KeraRing) for the Management of Central Keratoconus
• Actual Study Start Date: Jun 1, 2019
• Anticipated Primary Completion Date: Apr 1, 2023
• Anticipated Study Completion Date: Apr 1, 2023

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: Pocket ICRS Patients in this group are planned to undergo KeraRing 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 4-mm width.
Active Comparator: Tunnel ICRS Patients in this group are planned to undergo 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.

Outcome Measures

Primary Outcome Measures

1. Uncorrected distance visual acuity (UDVA) [6 months]

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

2. Corrected distance visual acuity (CDVA) [6 months]

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

3. Postoperative Refraction [6 months]

   Spherical equivalent refraction measured by Topcon Auto-Keratorefractometer

4. Postoperative keratometry [6 months]

   Postoperative keratometry as measured by Scheimpflug imaging Pentacam

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 35 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Tiba Eye Center	Assiut		Egypt	71516

Sponsors and Collaborators

• Assiut University

Investigators

• Principal Investigator: Mahmoud Abdel-Radi, MD, Assiut University

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Mahmoud Abdel-Radi, Principal Investigator, Assiut University
• ClinicalTrials.gov Identifier: NCT05748847
• Other Study ID Numbers: PVTICRS
• First Posted: Mar 1, 2023
• Last Update Posted: Mar 1, 2023
• Last Verified: Feb 1, 2023

• Individual Participant Data (IPD) Sharing Statement: No
• Plan to Share IPD: No
• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No
• Keywords provided by Mahmoud Abdel-Radi, Principal Investigator, Assiut University: Keratoconus; Femtosecond laser-assisted ICRS; Central keratoconus; KeraRing
• Additional relevant MeSH terms: Keratoconus

Study Results

No Results Posted as of Mar 1, 2023