Keraring Implantation Based on Alfonso Nomogram

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

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07540208

Enrollment

Registered

2026-04-20

Start date

2025-03-01

Completion date

2026-09-01

Last updated

2026-04-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Keratoconic Subjects

Keywords

Keratoconus, Intrastromal corneal rings, Alfonso nomogram

Brief summary

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.

Interventions

PROCEDUREIntrastromal 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.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 35 Years

Healthy volunteers

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.

Design outcomes

Primary

Measure	Time frame	Description
Corrected distance visual acuity	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.
Spherical equivalent refraction	6 months	Spherical equivalent in diopters is measured with Topcon autorefractometer.
Maximum keratometry	6 months	The maximum keratometry in diopters is measured using pentacam.

Countries

Egypt

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 21, 2026