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

February 1, 2016 updated by: Shahzad Mian, University of Michigan

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.

Study Overview

Status

Withdrawn

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Michigan
      • Ann Arbor, Michigan, United States, 48105
        • Cornea Clinic, Kellogg Eye Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 70 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
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
pre operative and 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months post-operative

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Michigan

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2004

Primary Completion (ACTUAL)

September 1, 2008

Study Completion (ACTUAL)

December 1, 2015

Study Registration Dates

First Submitted

December 4, 2008

First Submitted That Met QC Criteria

December 4, 2008

First Posted (ESTIMATE)

December 5, 2008

Study Record Updates

Last Update Posted (ESTIMATE)

February 3, 2016

Last Update Submitted That Met QC Criteria

February 1, 2016

Last Verified

February 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HUM 18730-IDES

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Subscribe