Keraring Implantation Based on Alfonso Nomogram

April 17, 2026 updated by: Mahmoud Abdel-Radi, Assiut University

Outcomes of Keraring Implantation in Patients With Keratoconus Guided by the Alfonso Morphological Surgical Nomogram

Keratoconus (KC) is a bilateral asymmetric progressive corneal degenerative disease associated with corneal thinning and protrusion. The management of moderate progressive keratoconus involves halting its progression through corneal cross-linking as well as flattening of the ectatic steep cornea through the implantation of intrastromal corneal rings (ICR). Different nomograms were used to guide ophthalmic surgeons for the proper choice of ICR implantation to achieve the best results. The aim of the current study is to assess the visual, refractive and tomographic outcomes of Keraring implantation based on the Alfonso nomogram, in patients with keratoconus.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

25

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Egypt
    • Asyut Governorate
      • Asyut, Asyut Governorate, Egypt, 71515
        • TIBA Eye Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients aged between 18-35 years.
  • Patients diagnosed with progressive keratoconus.
  • Mean keratometry (Km) between 48-60 D.
  • Clear cornea

Exclusion Criteria:

  • Mild or advanced keratoconus
  • Corneal scarring.
  • Other corneal or ocular diseases.
  • Systemic diseases such as diabetes mellitus and autoimmune diseases.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Keraring implantation based on Alfonso nomogram
Patients with moderate progressive keratoconus, underwent Keraring implantation based on Alfonso morphological surgical nomogram.
Procedure: Intrastromal corneal ring segment implantation (ICRS)
Patients with moderate progressive keratoconus underwent femtosecond laser-assisted intrastromal corneal ring (Keraring) implantation based on the Alfonso morphological surgical nomogram.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Corrected distance visual acuity
Time Frame: 6 months
Corrected distance visual acuity is measured with Snellen's acuity chart and converted to logarithm of the minimum angle of resolution (logMAR) notation.
6 months
Spherical equivalent refraction
Time Frame: 6 months
Spherical equivalent in diopters is measured with Topcon autorefractometer.
6 months
Maximum keratometry
Time Frame: 6 months
The maximum keratometry in diopters is measured using pentacam.
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Assiut University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2025

Primary Completion (Actual)

March 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

April 13, 2026

First Submitted That Met QC Criteria

April 17, 2026

First Posted (Actual)

April 20, 2026

Study Record Updates

Last Update Posted (Actual)

April 20, 2026

Last Update Submitted That Met QC Criteria

April 17, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OKIPKGASN

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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