Clinical trial NCT00761826: Study of the MEL 80 Excimer Laser Using LASIK in the Treatment of Mixed Astigmatism
Official title: A Prospective Multicenter Trial To Evaluate The Safety And Effectiveness Of The MEL 80 Excimer Laser Using LASIK (Laser In Situ Keratomileusis) For The Correction Of Naturally Occuring Mixed Astigmatism Up To 6.0 D
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Mixed Astigmatism
Keywords: Mixed Astigmatism
Laser In Situ Keratomileusis
Laser Therapy
Laser Corneal Surgery
Refractive Surgical Procedures
Ophthalmologic Surgical Procedure
Operative Surgical Procedures
Therapeutics
Lead sponsor: Carl Zeiss Meditec, Inc.
Sponsor class: INDUSTRY
First posted: 2008-09-30
Enrollment: 126
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: The purpose of this study is to determine whether the MEL 80 Excimer Laser is effective in the treatment of mixed astigmatism up to 6.0 D, when used as part of the Laser In Situ Keratomileusis (LASIK) procedure.

Detailed description: LASIK has become one of the most common refractive eye procedures performed in the country. In the mixed astigmatism procedure, a combination of both a steepening (hyperopic treatment) and a flattening (myopic treatment) occur on the corneal surface. The surgeon will produce a standard keratomileusis flap using a microkeratome, exposing the corneal stroma. Recontouring under the flap is then accomplished by the removal of tissue from the stroma with the laser. This recontouring results in an altering of effective lens power of the central cornea, measured in diopters (D). The MEL 80 Excimer Laser System will be evaluated for its ability to create accurate and stable mixed astigmatic refractive correction results.

Eligibility criteria: Inclusion Criteria:

* Naturally occurring mixed astigmatism when the magnitude of cylinder (up to 6.0 D) is greater than the magnitude of sphere, and the cylinder and sphere have opposite signs, at the spectacle plane;
* Have a stable refraction for at least the past twelve months, as demonstrated by a change of less than or equal to 0.50 D preoperative spherical equivalent shift over twelve months prior to surgery;
* Discontinue use of contact lenses at least 2 weeks for hard contacts and 3 days for soft lenses prior to the preoperative examination;
* Hard contact lens wearers must have two central keratometry readings and two manifest refractions taken at least one week apart that do not differ by more than 0.50 D
* Have visual acuity correctable to at least 20/40 in both eyes
* Have no more than 0.75 D of latent hyperopia as determined by the difference between the preoperative manifest refractive spherical equivalent (MRSE) and cycloplegic refractive spherical equivalent (CRSE);
* Be at least 18 years of age
* Corneal topography should be normal;
* The operative eye must be targeted for emmetropia;
* Be willing and able to return for scheduled follow-up examinations for twelve months after surgery;
* and provide written informed consent.

Exclusion Criteria:

* History of anterior segment pathology, including cataracts (in the operative eye);
* Clinically significant dry eye syndrome unresolved by treatment;
* Residual, recurrent, active ocular or uncontrolled eyelid disease, corneal scars within the ablation zone or other corneal abnormality such as recurrent corneal erosion or severe basement membrane disease;
* Ophthalmoscopic signs of keratoconus (or keratoconus suspect);
* Required ablation is deeper than 250 microns from the corneal endothelium;
* Irregular or unstable (distorted/not clear) corneal mires on central keratometry readings;
* Blind in the fellow eye;
* Previous intraocular or corneal surgery of any kind in the operative eye(s), including any type of surgery for either refractive or therapeutic purposes;
* History of ocular Herpes zoster or Herpes simplex keratitis;
* History of steroid-responsive rise in intraocular pressure, glaucoma, or preoperative IOP \>21 mm Hg;
* Diabetes, diagnosed autoimmune disease, connective tissue disease or clinically significant atopic syndrome;
* Immunocompromised patients, or use of chronic systemic corticosteroid or other immunosuppressive therapy;
* Pregnant, lactating, or child-bearing potential and not practicing a medically approved method of birth control;
* Sensitivity to planned study medications;
* Simultaneous participation in other ophthalmic drug or device clinical trial.
* For Fellow (Second) Eyes in Simultaneous Bilateral Treatment Procedures
* 1. Flap complications during the first eye's surgery such as a free cap, partial flap, thin flap, or irregular flap.
* 2. Epithelial defect exceeding 2 mm x 2 mm in dimension, or clinically significant debris in the interface between the flap and underlying stroma for the first eye.
* 3. Severe blepharospasm in the first eye that may have prevented or impeded the completion of the keratectomy and/or the laser ablation procedure.
* 4. Poor subject cooperation with instructions for the first eye's surgery and/or poor subject fixation on the laser fixation target.
* 5. Aborted LASIK procedure in the first eye or PRK was performed in the first eye because LASIK was not possible.

Primary outcomes:
measure: At the point of stability, a minimum of 75% of eyes should have an achieved refraction within ± 1.00 D of the intended outcome, and at least 50% of eyes should be within ± 0.50 D of the intended outcome.
timeFrame: Point of stability
measure: A minimum of 85% of eyes should have an uncorrected visual acuity of 20/40 or better at the postoperative interval at which stability has been established.
timeFrame: Point of stability
measure: A minimum of 95% of eyes should have a change of < 1.00 D in manifest refraction spherical equivalent (MRSE) between 2 refractions performed at least 3 months apart, and the mean rate of MRSE change per month should be < 0.04 D.
timeFrame: Point of stability
measure: Distance BSCVA of worse than 20/40 at the postoperative interval at which stability has been established should occur in less than 1.0 % of eyes that had a BSCVA of 20/20 or better before surgery.
timeFrame: Point of stability
measure: Loss of more than 2 lines of BSCVA should occur in less than 5.0 % of eyes.
timeFrame: Postoperative visits
measure: Incidence of adverse events to occur in less than 1% of eyes
timeFrame: Postoperative visits
Secondary outcomes:
measure: Subject Satisfaction: As measured by a subjective questionnaire, and will be considered as a secondary efficacy variable.
timeFrame: Postoperative visits 3, 6, 9 and 12 months
measure: Incidence of complications
timeFrame: Postoperative visits
measure: Patient Symptoms: As measured by a subjective questionnaire, will be considered as a secondary safety variable.
timeFrame: Preoperative and Postoperative visits 3, 6, 9 and 12 months
Other outcomes:
Locations:
city: San Diego
country: United States
facility: US Navy Refractive Surgery Center
state: California
city: Greenwood Village
country: United States
facility: Dishler Laser Institute
state: Colorado
city: Kansas City
country: United States
facility: Discover Vision Centers
state: Missouri
city: Eugene
country: United States
facility: Fine, Hoffman, and Packer
state: Oregon
city: Madison
country: United States
facility: Davis Duehr Dean Eye Clinic
state: Wisconsin
Study officials:
affiliation: Discover Vision Centers
name: John Doane, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Fine, Hoffman, and Packer LLC
name: Richard Hoffman, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Fine, Hoffman, and Packer LLC
name: Howard Fine, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: FIne, Hoffman, and Packer LLC
name: Mark Packer, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: US Navy Refractive Surgery Center, San Diego, CA
name: David Tanzer, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Davis Duehr Dean Eye Clinic
name: John Vukich, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Dishler Laser Institute
name: Jon Dishler, MD
role: PRINCIPAL_INVESTIGATOR
References: