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Completed

NCT Number: NCT05748847

Pocket Versus Tunnel ICRS for Treatment of 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.

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Key information

Conditions

Keratoconus Corneal Diseases Eye Diseases

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Tiba Eye Center

Asyut, Asyut Governorate, 71516, Egypt

About this study

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

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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.

Exclusion criteria

  • 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

Treatment and study plan

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.

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.

Primary outcomes

  1. Complications

    Time frame: 12 months

    Postoperative complications following intrastromal corneal ring segment implantation.

  2. Postoperative keratometry

    Time frame: 12 months

    Postoperative keratometry as measured by Scheimpflug imaging Pentacam

  3. Postoperative Refraction

    Time frame: 12 months

    Spherical equivalent refraction measured by Topcon Auto-Keratorefractometer

  4. Corrected distance visual acuity (CDVA)

    Time frame: 12 months

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

  5. Uncorrected distance visual acuity (UDVA)

    Time frame: 12 months

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

Sponsors and collaborators

Lead sponsor

Assiut University

Other

Registry information

Official study title

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

Important dates

Study start
2019
Primary completion
2023
Study completion
2023
First posted
Mar 1, 2023
Registry last updated
Oct 31, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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