the investigator will evaluate the change in endothelial cell count in eyes implanted with the iris-claw phakic Artisan lens for treatment of moderate to high myopia using specular microscopy

Iris-fixated phakic intraocular lenses (pIOLs) are used worldwide to correct high myopia, hyperopia, and astigmatism. It is used to correct high degrees of myopia in patients for whom laser excimer refractive surgery is not indicated.

The Artisan lens is designed to minimize the contact between the iris and the IOL resulting in less halo and glare from the prism effect.

Several clinical studies show that the visual results of the Artisan lens are stable and predictable. Artisan phakic IOLs provides precise predictability.

There have been concerns that the anterior chamber lens could damage the endothelial cell layer because of its proximity to the cornea. The manufacturer advises using the Artisan lens only in eyes with an ECD greater than 2000 cells/mm2 and an ACD greater than 2.6 mm.

Corneal endothelium is metabolically active and responsible for keeping the corneal stroma in its usual dehydrated state of 70% water.

loss of endothelial cells from increasing age, trauma, disease, or corneal surgery can reduce the density of endothelial cells and affect the ability of the endothelium to maintain it's primary function.

Alterations in the corneal endothelium depend on surgical technique and style; although endothelial cell loss is mainly the result of surgical trauma, continuous endothelial cell loss can occur. Late corneal decompensation often occurs in the absence of direct intraoperative endothelial trauma. These complications can be explained by the toxic effect of inflammatory mediators on the corneal endothelium.

Specular microscopy is used to view and record non-invasively the image of the corneal endothelial cell layer.

Inclusion Criteria:

• an age greater than 20 years, stable myopia with a variation in spherical equivalent of less than -0.50 diopter (D) during the 12 month preoperative period, a normal anterior segment with an ACD (i.e., the area between the corneal endothelium and the central anterior lens capsule) greater than 3.00 mm, an endothelial cell count of 2000 cells/mm2 or greater, no corneal, pupil, or iris abnormalities; and no history of glaucoma and chronic or recurrent uveitis , having contraindications to laser in situ keratomileusis based on pachymetric data or other corneal shape characteristics, and an intraocular pressure of 20 mm Hg or less.

Exclusion Criteria:

• an ACD less than 3.0 mm, history of ocular surgery, glaucoma, chronic uveitis, or preexisting ocular pathologic features or abnormalities.

patients with Artisan PIOL