Correlation Between Q-value Changes and Progression of Pediatric Keratoconus.

Correlation Between Changes in Corneal Asphericity and Progression of Keratoconus in Children

Keratoconus is a progressive corneal disease characterized by asymmetric corneal thinning and structural changes in corneal collagen which leads to decrease in visual acuity due to myopic shift, irregular astigmatism or corneal scarring. Early detection of the disease in children aids in halting the progression and improve their quality of life. There is no consensus regarding the progression criteria of the disease, we aimed to assess the changes in corneal asphericity in children after corneal collagen crosslinking and investigate any possible correlation with progression criteria widely used.

Study Overview

• Status: Completed
• Conditions: Collagen Diseases; Keratoconus; Corneal Disease
• Intervention / Treatment: Procedure: Transepithelial Corneal Collagen Cross-linking; Diagnostic test: Scheimpflug camera

Detailed Description

The Keratoconus progression is defined as increasing by 1.0 diopter (D) or more in the maximum keratometry (Kmax), progressive deterioration in Minimal Corneal Thickness is also associated with KC progression, other methods have been investigated to confirm KC progression such as changes in manifest refraction, unaided visual acuity (UAVA), BCVA, posterior keratometric data and higher order aberrations (HOA) which are altered in KC and can aid to confirm disease progression. Q-value (a coefficient of corneal asphericity) reflects the shape of the cornea, its refractive power, and spherical aberration. The mean Q-value in normal cornea is -0.26 ± 0.18, the severity of KC and the Q-value are inversely related.

Mean Q-value in KC at 8mm zone is -0.84 and -1.10 for anterior and posterior corneal surfaces, respectively. Until now, no precise criteria of KC progression especially in cases had undergone previous trans-epithelial corneal collagen cross-linking (TE-CXL) to halt the progression of the disease. In the present study we aimed to analyze the correlation between the changes in Q-value and progression of the KC in children had undergone bilateral TE-CXL.

• Study Type: Observational
• Enrollment (Actual): 9

Contacts and Locations

Study Locations

• Egypt
  • Benha
    • Banhā, Benha, Egypt, 13511
      • Ahmed Abdelshafy Tabl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 6 years to 16 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

This retrospective observational study was performed at Ophthalmology department, Benha University, EGYPT using the medical records of 9 children diagnosed as bilateral progressive KC that was confirmed by Pentacam according to amsler criteria, patients had undergone bilateral TE-CXL in the period from January 2016 to August 2016 and completed annual visits till 5 years of follow-up.

Description

Inclusion Criteria:

Children that were diagnosed as bilateral progressive KC (stage I-III, according to amsler classification, Kmax change >1D between 2 scanning with at least 2 months apart), and their age were less than 16 years old at time of TE-CXL, topographic parameters were Kmax 47-60D and MCT more than 400μm.

Exclusion Criteria:

Eyes with central corneal scarring, amblyopic eyes, and other corneal pathologies that may alter Pentacam scanning.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Progression Group (P-group); Eyes that showed progression of the disease after trans-epithelial corneal collagen cross-linking during the 5 years of follow-up, (number of eyes = 7 eyes).	Procedure: Transepithelial Corneal Collagen Cross-linking; Bilateral Transepithelial Corneal Collagen Cross-linking was done for all subjects using power of 9mW/cm2 at 55mm from the cornea for 10 minutes, with a total energy of 5.4j/cm2 using the (CCL VARIO, PESCHKE Trade GmbH, Huenenberg Switzerland), in the period between January 2016 to August 2016.; Other Names: TE-CXL; Diagnostic test: Scheimpflug camera; Pentacam (OCULUS Optikgeräte GmbH, Wetzlar, Germany) was done for all subjects at baseline and annually after TE-CXL till 5 years of follow-up.; Other Names: Pentacam
No Progression Group (NP-group); Eyes that showed no progression of the disease after trans-epithelial corneal collagen cross-linking during the 5 years of follow-up, (number of eyes = 11 eyes).	Procedure: Transepithelial Corneal Collagen Cross-linking; Bilateral Transepithelial Corneal Collagen Cross-linking was done for all subjects using power of 9mW/cm2 at 55mm from the cornea for 10 minutes, with a total energy of 5.4j/cm2 using the (CCL VARIO, PESCHKE Trade GmbH, Huenenberg Switzerland), in the period between January 2016 to August 2016.; Other Names: TE-CXL; Diagnostic test: Scheimpflug camera; Pentacam (OCULUS Optikgeräte GmbH, Wetzlar, Germany) was done for all subjects at baseline and annually after TE-CXL till 5 years of follow-up.; Other Names: Pentacam

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in corneal asphericity (Q-value) in all subjects.	Evaluate the changes in Q-value after Trans-epithelial corneal collagen cross-linking (TE-CXL) using pentacam.	Baseline and annually after TE-CXL till 5 years of follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between Q-value changes and disease progression in both groups.	Correlation between the changes in Q-value in different corneal zones and maximum keratometry and minimal corneal thickness in both groups over 5 years of follow-up.	Baseline and annually after TE-CXL till 5 years of follow-up
The Q-value as a predictive value in keratoconus progression.	The possibility of using the Q-value parameters as a predictive values to confirm keratoconus progression in children.	Baseline and annually after TE-CXL till 5 years of follow-up

Collaborators and Investigators

• Sponsor: Benha University
• Investigators: Principal Investigator: Ahmed A Tabl, MD, Benha University

Study record dates

Study Major Dates

• Study Start (Actual): October 9, 2021
• Primary Completion (Actual): October 25, 2021
• Study Completion (Actual): October 28, 2021

Study Registration Dates

• First Submitted: October 29, 2021
• First Submitted That Met QC Criteria: October 29, 2021
• First Posted (Actual): November 10, 2021

Study Record Updates

• Last Update Posted (Actual): November 10, 2021
• Last Update Submitted That Met QC Criteria: October 29, 2021
• Last Verified: October 1, 2021

More Information

Terms related to this study

• Keywords: corneal asphericity; corneal collagen cross-linking; Q-value; Pediatric keratoconus; Trans-epithelial
• Additional Relevant MeSH Terms: Eye Diseases; Musculoskeletal Diseases; Connective Tissue Diseases; Rheumatic Diseases; Collagen Diseases; Keratoconus; Corneal Diseases
• Other Study ID Numbers: RC-10-7-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No