Simultaneous Corneal Wavefront-Guided Trans-PRK and Corneal Collagen Crosslinking After ICRS Implantation for Moderate Keratoconus

Completed

• Conditions: Moderate Keratoconus
• Interventions: Procedure: combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK); Procedure: accelerated corneal collagen cross-linking (CXL)

• Registration Number: NCT03355430
• Lead Sponsor: Yonsei University

Brief Summary

The investigators aim to investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus. Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL. Corneal biomechanical properties were measured using the dynamic Scheimpflug analyzer at approximately the same time of day.

Detailed Description

The investigators aim to investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus. Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL. Corneal biomechanical properties were measured using the dynamic Scheimpflug analyzer at approximately the same time of day. The dynamic Scheimpflug analyzer automatically calculated corneal deformation amplitude, radius values, and maximal concave power when the cornea is deformed to its greatest curvature by the air puff. The deformation amplitude is defined as the maximum amplitude when the cornea is deformed to its greatest concave curvature and is influenced by corneal stiffness. The radius values represent the central concave curvature at the highest concavity (depressed to the highest concavity), while maximal concave power is the inverse radius of the curvature at the highest concavity.

Study Timeline

• Study Start: 2016-07-07
• Primary Completion: 2017-01-02
• Study Completion: 2017-01-02
• Status Verified: 2017-11
• Study First Submitted: 2017-11-20
• Study First Submitted QC: 2017-11-20
• Last Update Submitted: 2017-11-20
• Study First Posted: 2017-11-28
• Last Update Posted: 2017-11-28

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 23

Inclusion Criteria

• intolerant to contact lenses
• moderate keratoconus without apical scarring
• if progression had been noted over the previous 6 months
• All included patients underwent combined corneal wavefront-guided tPRK and CXL at least 1 month (average 2.7 ± 1.1 months; range 1 to 4 months) after ICRS implantation.

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Exclusion Criteria

• central or para-central corneal scarring
• central pachymetry < 400 microns
• corneal endothelial cell density of less than 2000 cells/mm2
• systemic autoimmune disease
• a history of herpetic corneal disease
• pregnancy
• lactation
• severe dry eye syndrome

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
moderate keratoconus group	accelerated corneal collagen cross-linking (CXL)	moderate keratoconus group underwent combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation
moderate keratoconus group	combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK)	moderate keratoconus group underwent combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation

Primary Outcome Measures

Name	Time	Method
visual acuity	6-month after tPRK-CXL	visual acuity in eyes undergoing combined corneal wavefront-guided transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking after intracorneal ring segment implantation in patients with moderate keratoconus

Secondary Outcome Measures

Name	Time	Method
Corneal indices	6-month after tPRK-CXL	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

Trial Locations

Locations (1)

Department of Ophthalmology, Yonsei University College of Medicine; 🇰🇷 Seoul, Korea, Republic of