What are Phakic Intraocular Lenses?
Phakic intraocular lenses are inserted inside the eye to correct refractive errors. These lenses are able to correct larger amounts of refractive errors such as myopia than other methods such as LASIK. These are different from regular intraocular lenses used for cataract surgery where the natural human lens is removed. Surgery with phakic intraocular lenses, the natural lens is left in place.
The History of the Development of Phakic Intraocular Lenses
The first lenses were placed in the anterior chamber angle in the 1950s and were associated with corneal decompensation, inflammation, and secondary glaucoma. Many of the regular intraocular lenses in the same time period had similar problems due to the design and materials used in the lenses.
Types of Phakic Intraocular Lenses
Verisyse Phakic Intraocular Lens
This was the first FDA approved phakic iris-fixated (iris claw lens) intraocular lens that is attached to the iris. This avoided many of the complications of the previous phakic intraocular lenses.
Visian Phakic Intraocular Lens
The Visian implantable collamer lens (ICL) was developed by Staar Surgical. This lens is inserted behind the iris and in front of the natural lens. The size and shape of the lens is important as to not touch the iris or the natural lens.
Veriflex and Acrysof Phakic Lenses
These are under FDA investigation at this time. They do not have approval at this time.
Insertion Methods of Inserting Phakic Intraocular Lenses
Anterior Chamber Lenses
After topical drops to constrict the pupil, topical anesthetic drops or an injection of anesthetic is used to numb the eye. An incision in the cornea is placed to allow insertion of the iris fixation lens. One or two small side incisions in the cornea are made to allow for instruments to be inserted to help with placing the lens in the eye. The lens is aligned horizontally and a piece of the iris is caught by the haptics of the lens. A peripheral iridotomy or iridectomy is performed either before the surgery with a laser or during the surgery.
Posterior Chamber Lenses
After topical anesthetic eye drops are used to numb the eye, a corneal incision is made to allow insertion of the lens. The lens is injected into the eye rolled up through an injector. The lens is inserted into the eye in front of the natural lens and behind the iris. A peripheral iridotomy or iridectomy is performed by a laser before the surgery or during the surgery.
Complications Associated with Phakic Intraocular Lenses
Complications associated with intraocular surgery are infection, chronic inflammation, bleeding, elevated intraocular pressure with possible glaucoma, corneal decompensation, retinal edema, retina tears, and/or retinal detachment. Cataract formation has occurred in approximately three percent. These lenses provide an opportunity for people with large refractive errors to have their vision corrected. Their results have been very good.
Phakic intraocular lenses can correct larger amounts of refractive error especially myopia (nearsightedness). This may be the only method of correcting someone’s refractive error without a clear lensectomy (clear normal lens is removed without a cataract) with a regular lens.