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DEVICE DESCRIPTION
Intacs™ corneal ring segments are an ophthalmic medical device designed for the reduction or elimination of mild myopia from -1.00 to -3.00 diopters. When placed in the corneal stroma, outside of the patient's central optical zone, the product reshapes the anterior surface of the cornea. Intacs are designed to be placed in the periphery of the cornea, at approximately two-thirds depth, and are surgically inserted through a small radial incision in the corneal stroma. The Intacs product has been designed to allow removal or replacement.
INTENDED USE/INDICATION
Intacs are intended for the reduction or elimination of mild myopia (-1.00 to -3.00 diopters spherical
equivalent at the spectacle plane) in patients:
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who are 21 years of age or older;
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with documented stability of refraction as demonstrated by a change of
less than or equal to 0.50 diopter for at least 12 months prior to the preoperative examination; and
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where the astigmatic component is +1.00 diopter or less.
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INDIVIDUALIZATION OF TREATMENT
The following chart relates Intacs thickness with the recommended prescribing range.
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Intacs
Thickness
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Predicted Nominal Correction
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Recommended Prescribing Range
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0.25 mm
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–1.30 D
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–1.00 to –1.625 D
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0.30 mm
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–2.00 D
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–1.75 to –2.25 D
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0.35 mm
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–2.70 D
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–2.375 to –3.00 D
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CONTRAINDICATIONS
Intacs are contraindicated: in patients with collagen vascular,
autoimmune or immunodeficiency diseases; in pregnant or nursing women; in the presence of ocular conditions, such as keratoconus,
recurrent corneal erosion syndrome or corneal dystrophy, that may predispose the patient to future complications; or in patients who
are taking one or more of the following medications: isotretinoin (Accutane1); amiodarone (Cordarone2); sumatriptan (Imitrex3).
WARNINGS
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Use of the Vacuum Centering Guide subjects the eye to increased
intraocular pressure. Continuous application of vacuum should be limited to 3 minutes or less and to no more than 750 mBar.
If it is necessary to reapply the Vacuum Centering Guide, wait 5 minutes to allow normal vascular perfusion of the eye to occur before reestablishing suction.
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Intacs are not recommended in patients with systemic diseases likely to
affect wound healing, such as insulin-dependent diabetes or severe atopic disease.
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Intacs are not recommended in patients with a history of ophthalmic Herpessimplex or Herpeszoster.
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Intacs are intended for single use only; do not reuse or resterilize.
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PRECAUTIONS
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Patients who receive the 0.35 mm Intacs may experience a reduced
outcome as compared to patients who receive the 0.25 mm or 0.30 mm Intacs product. Additionally, there may be an
increased removal rate for 0.35 mm patients due to dissatisfaction with their outcomes.
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Patients with myopia of -1.00 diopter are more likely to be
overcorrected.
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The long-term effect of Intacs on endothelial cell density has not been
established.
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A temporary decrease in central corneal sensation has been noted in
some patients. No clinical consequences were demonstrated in the U.S. clinical trials.
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Some patients with large dilated pupil diameters (
 7.0 mm) are predisposed to low light visual symptoms postoperatively and should be appropriately advised. |
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Under mesopic conditions, patients may experience some loss in contrast
sensitivity at low spatial frequencies (1.5 cycles per degree).
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The safety and effectiveness of alternative refractive procedures
following the removal of Intacs have not been established.
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The safety and effectiveness of Intacs have NOT been established:
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—
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in patients with progressive myopia or astigmatism, nuclear sclerosis
or other crystalline lens opacity, corneal abnormality, or previous corneal surgery or trauma;
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—
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for patients under 21 years of age;
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—
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for corneas that are steeper than 46 diopters or flatter than
40 diopters;
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—
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for corneas with a central thickness less than 480 microns or
peripheral thickness less than 570 microns;
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—
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in patients with greater than -3.50 diopters of myopia or with
astigmatism greater than +1.00 diopter; or
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—
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in long-term use.
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ADVERSE EVENTS/COMPLICATIONS
Five adverse events (AEs) have occurred in the U.S. clinical
studies resulting in an overall AE incident rate of 1.1%: one infection (0.2%), one shallow Intacs placement requiring removal (0.2%), one
incident of a loss of 2 lines of BSCVA that was subsequently regained (0.2%) and two incidents of anterior chamber perforation
(0.4%). No AE patient had a permanent BSCVA loss or clinically meaningful sequelae.
By Month 12, Intacs had a 4.5% incidence of removal, a 0.9%
incidence of exchange and a 0.7% incidence of secondary surgical interventions that were clinically meaningful.
Ocular complications were reported in conjunction with the U.S.
clinical studies. Complications that occurred in at least 1.0% of patients at Month 12 include: overcorrection (6%), reduction in
central corneal sensation (5.5%), difficulty with night vision (4.8%), undercorrection (4%), induced astigmatism (3.7%), blurry vision
(2.9%), double vision (1.6%), pannus (1.5%), halos (1.3%), glare (1.3%), single deep vessel (1.2%), fluctuating distance vision
(1.0%) and loss of
10 letters or 2 lines of BSCVA (1.0%).
Complications that occurred in less than 1.0% of patients at Month 12 include: fluctuating near vision, sensitivity to light, persistent
epithelial defect and iritis/uveitis.
PATIENT COUNSELING INFORMATION
The patient should receive the KeraVision Patient Booklet prior to
making the decision to undergo the KeraVision procedure.
HOW SUPPLIED
Intacs corneal ring segments are supplied sterile and are
nonpyrogenic. Intacs are intended for single use only; do not reuse or resterilize. In the event that the Intacs packaging is damaged, do
not use the product or attempt to resterilize.
KeraVision, Intacs, the KeraVision and Intacs logos are registered
trademarks or trademarks of KeraVision, Inc., in the U.S. and foreign countries. ©1999 KeraVision, Inc. All rights reserved.
MK-US-50057-01/Rev.A/Draft 06-03-99
1. Accutane® is a registered trademark of Roche Pharmaceuticals.
2. Cordarone® is a registered trademark of Wyeth-Ayerst Laboratories.
3. Imitrex® is a registered trademark of Glaxo-Wellcome, Inc.
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