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Completed

NCT Number: NCT03355430

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.

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Key information

Conditions

Moderate Keratoconus

Age range

20 year–45 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Department of Ophthalmology, Yonsei University College of Medicine

Seoul, 03722, South Korea

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK)

Procedure

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).

accelerated corneal collagen cross-linking (CXL)

Procedure

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).

Primary outcomes

  1. visual acuity

    Time frame: Pre-operation (baseline)

    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

  2. visual acuity

    Time frame: 1 minute before tPRK-CXL(transepithelial photorefractive keratectomy-accelerated corneal collagen cross-linking)

    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. visual acuity

    Time frame: 1 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

  4. visual acuity

    Time frame: 3-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

  5. visual acuity

    Time frame: 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 outcomes

  1. Corneal indices

    Time frame: Pre-operation (baseline)

    Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

  2. Corneal indices

    Time frame: 1 minute before tPRK-CXL

    Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

  3. Corneal indices

    Time frame: 1 month after tPRK-CXL

    Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

  4. Corneal indices

    Time frame: 3-month after tPRK-CXL

    Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

  5. Corneal indices

    Time frame: 6-month after tPRK-CXL

    Multiple corneal indices were measured at the 8-mm zone using the Scheimpflug tomography system (Pentacam HR; OCULUS).

Sponsors and collaborators

Lead sponsor

Yonsei University

Other

Registry information

Important dates

Study start
2016
Primary completion
2017
Study completion
2017
First posted
Nov 28, 2017
Registry last updated
Nov 28, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.