The Effect of Hinge Position and Hinge Width on Corneal Sensation and Dry Eye After IntraLase LASIK Procedure (IDES)

The recruitment status of this study is unknown because the information has not been verified recently.
Verified December 2008 by University of Michigan.
Recruitment status was  Recruiting
Sponsor:
Information provided by:
University of Michigan
ClinicalTrials.gov Identifier:
NCT00803478
First received: December 4, 2008
Last updated: NA
Last verified: December 2008
History: No changes posted
  Purpose

Corneal sensation is known to play a role in tear secretion. Decreased sensation leads to decreased tear production; and when bilateral, leads to a decreased blink rate as well. Dry eyes are a common side effect of LASIK. Incidence rates vary widely, but have been reported in as many as 59% of patients. And almost all patients have some transient dry eye symptoms immediately following LASIK.

Previous studies have looked at the effect of hinge position (superior vs. nasal) and hinge width on corneal sensation and dry eye after LASIK performed with a mechanical microkeratome. Corneal sensation was decreased and dry eye signs and symptoms increased immediately following LASIK in all eyes. These parameters then improved at all time periods between 1 week and 6 months post-operative. Loss of corneal sensation and dry eye signs and symptoms were greater in eyes with superior-hinge flap than nasal-hinge flap, and in eyes with narrower hinge flap rather than wider hinge flap IntraLase LASIK, using the IntraLase femtosecond laser rather than a mechanical microkeratome to cut the corneal flap, has become an increasingly popular procedure. It provides several advantages over mechanical microkeratomes, including reduced surgical complications, more predictable flap thickness, better astigmatic neutrality, decreased epithelial injury, and an ability to operate on a wider range of patients.

The investigators propose this study to evaluate the effect of flap hinge size and flap thickness in corneal flaps created with the IntraLase laser. The investigators would like to determine if there is a difference from the previously discussed results found when using the mechanical microkeratome. Also, with the increased ease of programming alternate hinge width or flap thickness with IntraLase, if the investigators find a significant difference with an alternate flap configuration, it might translate to a feasible change in clinical practice.


Condition Intervention
Myopia
Procedure: LASIK

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Effect of Hinge Position and Hinge Width on Corneal Sensation and Dry Eye After IntraLase LASIK Procedure

Further study details as provided by University of Michigan:

Primary Outcome Measures:
  • To evaluate the effect of hinge position (superior vs. temporal) , hinge width (45 vs. 90 degrees), and flap thickness on corneal sensation and dry eye after IntraLase LASIK. [ Time Frame: pre operative and 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months post-operative ] [ Designated as safety issue: No ]

Estimated Enrollment: 100
Study Start Date: June 2004
Estimated Study Completion Date: December 2009
Primary Completion Date: September 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Hinge position
superior vs. temporal
Procedure: LASIK
Active Comparator: Hinge width
45 vs 90 degrees
Procedure: LASIK
Active Comparator: Flap Thickness
110 vs 130 microns
Procedure: LASIK

Detailed Description:

Corneal innervation/sensation is supplied by the long ciliary nerves which branch from the trigeminal nerve. The nerves enter the cornea in the mid-stroma at the nasal and temporal limbus. They then branch and turn anterior to form a dense plexus sub-Bowman's layer. The nerves finally terminate in the wing cell layer from where they enervate the epithelium. Corneal sensation has been shown to be decreased after all corneal surgeries, including LASIK.

Corneal sensation is known to play a role in tear secretion. Decreased sensation leads to decreased tear production; and when bilateral, leads to a decreased blink rate as well. Dry eyes are a common side effect of LASIK. Incidence rates vary widely, but have been reported in as many as 59% of patients. And almost all patients have some transient dry eye symptoms immediately following LASIK.

Previous studies have looked at the effect of hinge position (superior vs. nasal) and hinge width on corneal sensation and dry eye after LASIK performed with a mechanical microkeratome.1,2 Corneal sensation was decreased and dry eye signs and symptoms increased immediately following LASIK in all eyes. These parameters then improved at all time periods between 1 week and 6 months post-operative. Loss of corneal sensation and dry eye signs and symptoms were greater in eyes with superior-hinge flap than nasal-hinge flap, and in eyes with narrower hinge flap rather than wider hinge flap IntraLase LASIK, using the IntraLase femtosecond laser rather than a mechanical microkeratome to cut the corneal flap, has become an increasingly popular procedure. It provides several advantages over mechanical microkeratomes, including reduced surgical complications, more predictable flap thickness, better astigmatic neutrality, decreased epithelial injury,3 and an ability to operate on a wider range of patients.

We propose this study to evaluate the effect of flap hinge position and size in corneal flaps created with the IntraLase laser. We would like to determine if there is a difference from the previously discussed results found when using the mechanical microkeratome. Also, with the increased ease of programming alternate hinge position and width with IntraLase, if we find a significant difference with an alternate flap configuration, it might translate to a feasible change in clinical practice.

Specific Aims: To evaluate the effect of hinge position (superior vs. temporal) , hinge width (45 vs. 90 degrees), and flap thickness on corneal sensation and dry eye after IntraLase LASIK.

  Eligibility

Ages Eligible for Study:   20 Years to 70 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Refractive error: Myopia < 12 D, with astigmatism < 3 D,
  • Age > 20 y/o
  • Regular corneal curvature, sufficient corneal thickness, appropriate pupil size, normal slit lamp examination
  • Informed consent to permit us to use their records for this study without using name, medical record number, or date of surgery.

Exclusion Criteria:

  • Pregnant/nursing
  • Systemic collagen vascular disease
  • Autoimmune disease
  • Severe dry eyes
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00803478

Contacts
Contact: Shahzad Mian, MD 734-615-5476 smian@umich.edu

Locations
United States, Michigan
Cornea Clinic, Kellogg Eye Center Recruiting
Ann Arbor, Michigan, United States, 48105
Principal Investigator: Shahzad Mian, MD         
Sponsors and Collaborators
University of Michigan
  More Information

No publications provided

Responsible Party: Shahzad Mian, MD, Opthalmology and Visual Sciences, Kellogg Eye Center, University of MIchiagn
ClinicalTrials.gov Identifier: NCT00803478     History of Changes
Other Study ID Numbers: HUM 18730-IDES
Study First Received: December 4, 2008
Last Updated: December 4, 2008
Health Authority: United States: Institutional Review Board

Keywords provided by University of Michigan:
IntraLase LASIK for primary myopia

ClinicalTrials.gov processed this record on October 21, 2014