The Characteristics of Backscattering With Depth in the Progression of Keratoconus

The Characteristics of Backscattering With Depth in the Progression of Keratoconus and Its Role in Forme Fruste Keratoconus Detection

To investigate the variation in backscattering with depth between forme fruste keratoconus (FFKC), keratoconus, and normal eyes; to determine the backscattering changes in the characteristics of keratoconus progression; and to explore the diagnostic value of backscattering in FFKC.

Study Overview

• Status: Completed
• Conditions: Elasticum, Incomplete Pseudoxanthoma

Detailed Description

To investigate the variation in backscattering with depth between forme fruste keratoconus (FFKC), keratoconus, and normal eyes; to determine the backscattering changes in the characteristics of keratoconus progression; and to explore the diagnostic value of backscattering in FFKC. A Scheimpflug corneal tomography image and caliper tool were used to obtain backscatter at every 2% depth at the thinnest point of the cornea, with the measured values expressed in grayscale units (GSU).

• Study Type: Observational
• Enrollment (Actual): 223

Contacts and Locations

Study Locations

• China
  • Tianjin
    • Tianjin, Tianjin, China
      • Tianjin Eye Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study was performed on patients with keratoconus and healthy participants admitted to Tianjin Eye Hospital from January 2020 to December 2022.

Description

Inclusion Criteria:

1. BCVA <20/20 and a history of myopia or astigmatism;
2. presence of any of the following positive signs on slit lamp examination: corneal stromal thinning, cone-shaped anterior protrusions, Fleischer's ring, Vogt's striae, epithelial or subepithelial scarring;
3. abnormal corneal topography (maximum keratometry (K) value of >47.2 diopters (D), bow-tie pattern with skewed radial axes, or inferior-superior asymmetry(3-mm I-S keratometric difference >1.4 D).

Exclusion Criteria:

1. Patients with severe corneal scarring that affected light scattering and density maps showing "black holes" 2.Participatients with other corneal diseases 3. Eyes that have undergone surgery or trauma 4. Eyes with corneal dystrophy

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Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort
forme fruste keratoconus; 1) no other eye abnormalities except myopia and astigmatism; 2) transparent cornea; 3) no positive signs of keratoconus on slit lamp examination or morphology examination (excluding the appearance of keratoconus as described above, and simultaneously satisfying A0B0C0D0, Index of Surface variance (ISV) < 30, and Keratoconus Index (KI) < 1.07); and 4) Belin/Ambrósio enhanced ectasia total derivation value(BAD-D)≤1.6
Clinical keratoconus; 46.5 D ≤ Mean K <52 D; 55≤ ISV<200; and 1.10 ≤ KI <1.50
severe keratoconus; Mean K ≥ 52D; ISV≥ 200; and KI≥ 1.50
normal eye; one eye of healthy participants before refractive surgery were randomly selected. Comprehensive ophthalmic examinations were performed before surgery, which confirmed that the cornea was clear and normal in shape. For this group, there was no family history of keratoconus, no other diseases except ametropia, and no corneal dilatation one year after surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
backscattering	Standard measurements were performed using a Pentacam (Pentacam HR; Oculus, Wetzlar, Germany);The average brightness of a predetermined area of the cornea was calculated, shown as densitometry, and recorded in GSU ranging from 0 to 100 (0, cornea is transparent without opacity; 100, cornea is completely opaque).	through study completion, an average of 1 year

Collaborators and Investigators

• Sponsor: Tianjin Eye Hospital

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2020
• Primary Completion (Actual): December 1, 2022
• Study Completion (Actual): December 30, 2022

Study Registration Dates

• First Submitted: September 8, 2023
• First Submitted That Met QC Criteria: September 18, 2023
• First Posted (Actual): September 22, 2023

Study Record Updates

• Last Update Posted (Actual): September 22, 2023
• Last Update Submitted That Met QC Criteria: September 18, 2023
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Skin Diseases; Eye Diseases; Congenital Abnormalities; Hematologic Diseases; Hemorrhagic Disorders; Genetic Diseases, Inborn; Connective Tissue Diseases; Hemostatic Disorders; Skin Diseases, Genetic; Corneal Diseases; Skin Abnormalities; Keratoconus; Pseudoxanthoma Elasticum
• Other Study ID Numbers: KY-2023020

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