Pocket Versus Tunnel ICRS for Treatment of Keratoconus

Not Applicable

Completed

• Conditions: Keratoconus
• Interventions: Procedure: Intrastromal corneal ring segment implantation (Pocket); Procedure: Intrastromal corneal ring segment implantation (Tunnel)

• Registration Number: NCT05748847
• Lead Sponsor: Assiut University

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.

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 Timeline

• Study Start: 2019-06-01
• Study First Submitted: 2023-02-19
• Study First Submitted QC: 2023-02-19
• Study First Posted: 2023-03-01
• Primary Completion: 2023-04-15
• Study Completion: 2023-04-15
• Status Verified: 2024-10
• Last Update Submitted: 2024-10-29
• Last Update Posted: 2024-10-31

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 74

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Pocket ICRS	Intrastromal corneal ring segment implantation (Pocket)	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.
Tunnel ICRS	Intrastromal corneal ring segment implantation (Tunnel)	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.

Primary Outcome Measures

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

Trial Locations

Locations (1)

Tiba Eye Center; 🇪🇬 Assiut, Egypt