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Femtosecond Laser Assisted Keratoplasty (FLAK)

Primary Purpose

Keratoconus

Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Femtosecond laser assisted keratoplasty
PKP
Sponsored by
University of Michigan
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Keratoconus

Eligibility Criteria

18 Years - 60 Years (Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

  1. Corneal opacification.
  2. Reduced ETDRS-measured, best corrected, distance visual acuity to 20/40 or worse.
  3. Ability to participate in follow-up visits.
  4. Signed, informed consent.

Exclusion Criteria:

  1. Corneal opacification adequately dense to obscure visualization of iris.
  2. ETDRS-measured, best-corrected, distance visual acuity of 20/30 or better.
  3. Corneal thickness greater than 1200 µm at the 9 mm peripheral zone.
  4. Severe corneal thinning including descemetocoele with impending corneal rupture.
  5. Prior PKP or incisional surgery that may provide a potential space into which the gas produced by the procedure can escape.
  6. Poor visual potential in the non-study eye (VA of 20/100 or less, without potential for improvement by the examining ophthalmologist's judgment).
  7. History of glaucoma, including steroid response rise in intraocular pressure.
  8. Active intraocular inflammation or infection.
  9. Age 18 or younger.
  10. Unable to return for scheduled follow-up examinations.
  11. Other medical condition(s) that will likely prevent long term follow-up.

Sites / Locations

  • Cornea Clinic, Kellogg Eye Center

Arms of the Study

Arm 1

Arm 2

Arm Type

Active Comparator

Active Comparator

Arm Label

FLAK

PKP

Arm Description

Femtosecond laser assisted keratoplasty

Penetrating Keratoplasty

Outcomes

Primary Outcome Measures

Investigate postoperative physiology and biomechanics after Femtosecond Laser Assisted Keratoplasty in human eyes.

Secondary Outcome Measures

Full Information

First Posted
December 4, 2008
Last Updated
March 13, 2017
Sponsor
University of Michigan
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1. Study Identification

Unique Protocol Identification Number
NCT00802776
Brief Title
Femtosecond Laser Assisted Keratoplasty
Acronym
FLAK
Official Title
Comparison of Femtosecond Laser-Assisted and Traditional Keratoplasty for Keratoconus
Study Type
Interventional

2. Study Status

Record Verification Date
March 2017
Overall Recruitment Status
Completed
Study Start Date
October 2007 (undefined)
Primary Completion Date
December 2010 (Actual)
Study Completion Date
January 2016 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
University of Michigan

4. Oversight

Data Monitoring Committee
No

5. Study Description

Brief Summary
Penetrating keratoplasty (PKP) is corneal transplantation performed by using round trephine blades to create matched circumferential incisions in both the diseased cornea and the donor cornea. The donor tissue graft is then secured in place with sutures which are usually removed postoperatively.The primary surgical goals are the preservation of a clear graft and improvement of vision. Surgical outcomes are limited by donor-recipient junction mismatch, astigmatism, rejection, infection and wound dehiscence. The femtosecond laser is a focusable, infrared laser capable of cutting tissue at various depths and in a range of patterns, and is currently being used to create corneal lamellar flaps in LASIK surgery. The laser parameters can be adjusted for submicron precision in cutting desired diameters, depths and shapes in the cornea, with minimal collateral injury. This technology is now capable of creating full-thickness corneal trephinations with customized locking edges at the graft-host junction between the donor and recipient corneas in Femtosecond Laser-Assisted Keratoplasty (FLAK). This approach may allow for better wound junction of the donor and recipient corneas, which in turn may also significantly reduce astigmatism, improve wound healing and visual recovery. This pilot study will help us determine optimal femtosecond laser spot size, separation, fluence, and energy which result in the best graft-host fit. The specific aim is to investigate postoperative physiology and biomechanics after FLAK in human eyes.
Detailed Description
Penetrating keratoplasty (PKP) or full-thickness corneal transplantation is a common and highly successful method to restore vision decreased by corneal opacification. Surgery is performed by using round trephine blades to create matched circumferential incisions in both the diseased cornea and the donor cornea. Several types of blades are currently available to create uniform corneal cuts. The donor tissue graft is then secured in place with sutures which are usually removed postoperatively after one to two years. The primary surgical goals are the preservation of a clear graft and improvement of vision. Surgical outcomes are limited by donor-recipient junction mismatch, astigmatism, rejection, infection and wound dehiscence. The femtosecond laser is a focusable, infrared laser capable of cutting tissue at various depths and in a range of patterns, and is currently being used to create corneal lamellar flaps in LASIK surgery. The laser parameters can be adjusted for submicron precision in cutting desired diameters, depths and shapes in the cornea, with minimal collateral injury. This technology is now capable of creating full-thickness corneal trephinations with customized locking edges at the graft-host junction between the donor and recipient corneas in Femtosecond Laser-Assisted Keratoplasty (FLAK). This approach may allow for better wound junction of the donor and recipient corneas, which in turn may also significantly reduce astigmatism, improve wound healing and visual recovery. Although the femtosecond laser has been approved by the FDA for use in corneal transplants, it has not been compared to standard corneal transplant techniques. This pilot study will help us determine optimal femtosecond laser spot size, separation, fluency, and energy which result in the best graft-host fit. Surgical eligibility criteria, including preoperative diagnoses, as well as possible associated medical and ophthalmic conditions for the eventual multi-center study will be defined. Primary outcome measures, which include corneal refractive power measurements, serial endothelial-cell counts to assess endothelial survival and vision-specific quality of life surveys, will be evaluated. The specific aim is to investigate postoperative physiology and biomechanics after FLAK in human eyes. The significance is that FLAK presents corneal surgeons with an opportunity to avoid some problems of PKP and offers a safer and more precise approach to treating visually disabling diseases secondary to corneal opacification.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Keratoconus

7. Study Design

Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Single Group Assignment
Masking
None (Open Label)
Allocation
Non-Randomized
Enrollment
24 (Actual)

8. Arms, Groups, and Interventions

Arm Title
FLAK
Arm Type
Active Comparator
Arm Description
Femtosecond laser assisted keratoplasty
Arm Title
PKP
Arm Type
Active Comparator
Arm Description
Penetrating Keratoplasty
Intervention Type
Procedure
Intervention Name(s)
Femtosecond laser assisted keratoplasty
Intervention Type
Procedure
Intervention Name(s)
PKP
Primary Outcome Measure Information:
Title
Investigate postoperative physiology and biomechanics after Femtosecond Laser Assisted Keratoplasty in human eyes.
Time Frame
Preoperatively and 1day, 1week and 1, 3, 6, 12, 18 and 24 months post operatively

10. Eligibility

Sex
All
Minimum Age & Unit of Time
18 Years
Maximum Age & Unit of Time
60 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: Corneal opacification. Reduced ETDRS-measured, best corrected, distance visual acuity to 20/40 or worse. Ability to participate in follow-up visits. Signed, informed consent. Exclusion Criteria: Corneal opacification adequately dense to obscure visualization of iris. ETDRS-measured, best-corrected, distance visual acuity of 20/30 or better. Corneal thickness greater than 1200 µm at the 9 mm peripheral zone. Severe corneal thinning including descemetocoele with impending corneal rupture. Prior PKP or incisional surgery that may provide a potential space into which the gas produced by the procedure can escape. Poor visual potential in the non-study eye (VA of 20/100 or less, without potential for improvement by the examining ophthalmologist's judgment). History of glaucoma, including steroid response rise in intraocular pressure. Active intraocular inflammation or infection. Age 18 or younger. Unable to return for scheduled follow-up examinations. Other medical condition(s) that will likely prevent long term follow-up.
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Shahzad Mian, MD
Organizational Affiliation
University of Michigan Kellogg Eye Center
Official's Role
Principal Investigator
Facility Information:
Facility Name
Cornea Clinic, Kellogg Eye Center
City
Ann Arbor
State/Province
Michigan
ZIP/Postal Code
48105
Country
United States

12. IPD Sharing Statement

Plan to Share IPD
No

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Femtosecond Laser Assisted Keratoplasty

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