Clinical trial NCT03355430: Simultaneous Corneal Wavefront-Guided Trans-PRK and Corneal Collagen Crosslinking After ICRS Implantation for Moderate Keratoconus
Official title: Simultaneous Corneal Wavefront-Guided Trans-PRK and Corneal Collagen Crosslinking After ICRS Implantation for Moderate Keratoconus
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Moderate Keratoconus
Lead sponsor: Yonsei University
Sponsor class: OTHER
First posted: 2017-11-28
Enrollment: 23
Sex: ALL
Minimum age (years): 20
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: no
Observational model: CASE_ONLY
Time perspective: RETROSPECTIVE
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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: visual acuity
timeFrame: Pre-operation (baseline)
measure: visual acuity
timeFrame: 1 minute before tPRK-CXL(transepithelial photorefractive keratectomy-accelerated corneal collagen cross-linking)
measure: visual acuity
timeFrame: 1 month after tPRK-CXL
measure: visual acuity
timeFrame: 3-month after tPRK-CXL
measure: visual acuity
timeFrame: 6-month after tPRK-CXL
Secondary outcomes:
measure: Corneal indices
timeFrame: Pre-operation (baseline)
measure: Corneal indices
timeFrame: 1 minute before tPRK-CXL
measure: Corneal indices
timeFrame: 1 month after tPRK-CXL
measure: Corneal indices
timeFrame: 3-month after tPRK-CXL
measure: Corneal indices
timeFrame: 6-month after tPRK-CXL
Other outcomes:
Locations:
city: Seoul
country: Korea, Republic of
facility: Department of Ophthalmology, Yonsei University College of Medicine
Study officials:
References:
citation: 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.