intacs prescription inserts for keratoconus patients

Conditions: Keratoconus

Summary: the us food and drug administration (fda) originally approved intacs prescription inserts in april 1999 for the correction of low levels of nearsightedness (-1.00 to -3.00 diopters). additional clinical data have shown that intacs are safe for the treatment of keratoconus, in july 2004, fda approved intacs inserts for the treatment of keratoconus as a humanitarian use device (fda approval letter attached). the statute and the implementing regulation of fda (21 cfr 814.124 (aj) require irb review and approval before a hud is used.intacs prescription inserts are composed of two clear segments, each having an arc length of 150°, they are manufactured form a biomedical material called polymethylmethacrylate (pmma) and are available in three thicknesses. two intacs inserts ranging from 0.250mm to 0.350mm may be implanted depending on the orientation of the cone and the amount of myopia and astigmatism to be reduced.

the intacs procedure is typically performed in an outpatient setting. the two tiny intacs inserts are surgically placed into the periphery of the cornea through a tiny cut that is made on the cornea after numbing drops have been applied. a specially designed instrument creates a tunnel by separating the tissue layers in the outside periphery of the cornea, the intacs inserts are placed into this tunnel where they remain. one or two ophthalmic sutures will be placed to close the incision. a postoperative care information booklet will be given to the patients; patients will be followed by means of postoperative appointments for up to 12 months after the surgery. the visits/testing schedules are listed below: pre-or visit (1.5 hours): visual acuity (va), refraction, topography, keratometry, glare test. mesopic pupil size, pachymetry, tonometry, slit lamp exam and contrast sensitivity. surgery (30min): at laser center for vision care which is part of aston and department of ophthalmology. post-or day 1(10min): va, slit lamp exam. post-or 1week (20min): visual acuity, refraction, topography, tonometry, slit lamp exam. post-or 1 month (20minj: visual acuity, refraction, topography, tonometry, slit lamp exam. post-or 3 month (1.5 hours): some as pre-op visit. post-or 6 month (20min): visual acuity, refraction, topography, tonometry, slit lamp exam. post-or 12 month (1.5 hours): same as pre-op.

Eligibility criteria:
inclusion criteria: who have experienced a progressive deterioration in their vision, such thot they can no longer achieve adequate functional vision on a daily basis with their contact lenses or spectacles; who are 21 years of age or older; who have clear central corneas; who have a corneal thickness of 450 microns or greater at the proposed incision site; who have corneal transplantation as the only remaining option to improve their functional vision. exclusion criteria: who have abnormally thin corneas or who have a corneal thickness of 449 microns or less at the proposed incision site; patients with collagen vascular, autoimmune or immunodeficiency disease; pregnant or nursing patients; presence of ocular conditions, such as recurrent corneal erosion syndrome or corneal dystrophy, that my predispose the patient to future complications; patients who are taking on or more of following medications: isotretinoin (accutane); amiodarone hcl (cordarone).

Keywords: cornea keratoconus steep cornea