Effectiveness and Safety of Corneal Collagen Cross Linking After Induction of Stromal Emphysema in Keratoconus

in this study we evaluated the effectiveness and safety of corneal collagen cross-linking in keratoconic eyes with thin cornea after induction of stromal emphysema prior to riboflavin instillation and UV-A corneal irradiation

Study Overview

• Status: Completed
• Conditions: Keratoconus
• Intervention / Treatment: Procedure: Corneal collagen cross-linking with induction of corneal stromal emphysema

• Study Type: Interventional
• Enrollment (Actual): 39
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Giza Governorate
    • Giza, Giza Governorate, Egypt, 11562
      • Department of Ophthalmology-Faculty of Medicine-Cairo University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Progressive KC proven by clinical examination, tomography, and pachymetry
• Thinnest corneal location thickness between 390 to 450 microns

Exclusion Criteria:

• Previous ocular Trauma or Surgery.
• History of herpetic eye disease
• Central corneal scarring
• Cornea guttata
• Ocular surface disease and dry eye disease
• Vernal and atopic keratoconjunctivitis
• Cataract
• Glaucoma, intraocular pressure less than 10 or more than 21 mmHg
• Posterior segment abnormalities
• Nystagmus or other conditions that interfere with patient's fixation
• Diabetes mellitus
• pregnancy
• Collagen vascular disease, autoimmune disease and patients receiving immunosuppressive therapy

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Patients with progressive keratoconus	Procedure: Corneal collagen cross-linking with induction of corneal stromal emphysema; Corneal collagen cross-linking with induction of corneal stromal emphysema

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluating effectiveness of Cross-linking in the presence of air in corneal stroma	Through serial corneal tomography	Corneal tomography will be performed preoperatively then 6, and 12 months after the procedure
Assessment of the safety of this procedure on corneal endothelial cells	By evaluating corneal endothelium structural integrity, using serial specular microscopy imaging	Specular microscopy will be performed preoperatively, then 1, 3 and 6 months after the procedure
Measuring demarcation line depth in microns from corneal epithelium	both reflectivity and depth (in microns) of demarcation line will be evaluated by using corneal OCT	one month after procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To detect changes in the visual acuity (in decimal)	Preoperative and postoperative examinations will be carried out for visual acuity, using Snellen visual acuity chart.	preoperatively then 1 week and 1, 3, 6, and 12 months after the procedure.

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2022
• Primary Completion (Actual): July 1, 2024
• Study Completion (Actual): October 1, 2024

Study Registration Dates

• First Submitted: January 6, 2026
• First Submitted That Met QC Criteria: February 19, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): February 23, 2026
• Last Update Submitted That Met QC Criteria: February 19, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Corneal Diseases; Keratoconus; Therapeutics; Drug Therapy; Combined Modality Therapy; Phototherapy; Photochemotherapy; Corneal Cross-Linking
• Other Study ID Numbers: MD-163-2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The datasets used and/or analyzed during this study are available from the principal investigator on reasonable request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No