Clinical trial NCT05748847: Pocket Versus Tunnel ICRS for Treatment of Keratoconus
Official title: Pocket Versus Tunnel Intrastromal Corneal Ring Segment Implantation (KeraRing) for the Management of Central Keratoconus
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Keratoconus
Keywords: Keratoconus
Femtosecond laser-assisted ICRS
Central keratoconus
KeraRing
Lead sponsor: Assiut University
Sponsor class: OTHER
First posted: 2023-03-01
Enrollment: 74
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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

Eligibility criteria: 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

Primary outcomes:
measure: Complications
timeFrame: 12 months
measure: Postoperative keratometry
timeFrame: 12 months
measure: Postoperative Refraction
timeFrame: 12 months
measure: Corrected distance visual acuity (CDVA)
timeFrame: 12 months
measure: Uncorrected distance visual acuity (UDVA)
timeFrame: 12 months
Secondary outcomes:
Other outcomes:
Locations:
city: Assiut
country: Egypt
facility: Tiba Eye Center
Study officials:
affiliation: Assiut University
name: Mahmoud Abdel-Radi, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.