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

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.

Study Overview

• Status: Completed
• Conditions: Moderate Keratoconus
• Intervention / Treatment: Procedure: combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK); Procedure: accelerated corneal collagen cross-linking (CXL)

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 Type: Observational
• Enrollment (Actual): 23

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of, 03722
    • Department of Ophthalmology, Yonsei University College of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 45 years (ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patient was intolerant to contact lenses, had moderate keratoconus without apical scarring, and 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. We excluded patients with 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, or severe dry eye syndrome.

Description

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.

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

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

moderate keratoconus group; 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

Procedure: combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK); After at least 1 month (average 2.7 ± 1.1 months; range 1 to 4 months), all patients were scheduled for combined corneal wavefront-guided tPRK and accelerated CXL treatment. tPRK between the corneal ring segments was performed using an excimer laser (Amaris 1050 Excimer Laser platform; Schwind eye-tech-solutions GmbH and Co KG, Kleinostheim, Germany).; Procedure: accelerated corneal collagen cross-linking (CXL); After at least 1 month (average 2.7 ± 1.1 months; range 1 to 4 months), all patients were scheduled for combined corneal wavefront-guided tPRK and accelerated CXL treatment. tPRK between the corneal ring segments was performed using an excimer laser (Amaris 1050 Excimer Laser platform; Schwind eye-tech-solutions GmbH and Co KG, Kleinostheim, Germany).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
visual acuity	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	Pre-operation (baseline)
visual acuity	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	1 minute before tPRK-CXL(transepithelial photorefractive keratectomy-accelerated corneal collagen cross-linking)
visual acuity	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	1 month after tPRK-CXL
visual acuity	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	3-month after tPRK-CXL
visual acuity	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	6-month after tPRK-CXL

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Corneal indices	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).	Pre-operation (baseline)
Corneal indices	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).	1 minute before tPRK-CXL
Corneal indices	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).	1 month after tPRK-CXL
Corneal indices	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).	3-month after tPRK-CXL
Corneal indices	Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).	6-month after tPRK-CXL

Collaborators and Investigators

• Sponsor: Yonsei University

Publications and helpful links

General Publications

• Lee H, Kang DSY, Ha BJ, Choi JY, Kim EK, Seo KY, Kim TI. Visual rehabilitation in moderate keratoconus: combined corneal wavefront-guided transepithelial photorefractive keratectomy and high-fluence accelerated corneal collagen cross-linking after intracorneal ring segment implantation. BMC Ophthalmol. 2017 Dec 29;17(1):270. doi: 10.1186/s12886-017-0666-1.

Study record dates

Study Major Dates

• Study Start (ACTUAL): July 7, 2016
• Primary Completion (ACTUAL): January 2, 2017
• Study Completion (ACTUAL): January 2, 2017

Study Registration Dates

• First Submitted: November 20, 2017
• First Submitted That Met QC Criteria: November 20, 2017
• First Posted (ACTUAL): November 28, 2017

Study Record Updates

• Last Update Posted (ACTUAL): November 28, 2017
• Last Update Submitted That Met QC Criteria: November 20, 2017
• Last Verified: November 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Corneal Diseases; Keratoconus
• Other Study ID Numbers: 4-2016-0403

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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