Phakic intraocular lenses (PIOL) are lenses used to correct nearsightedness or myopia, the most common refractive error of the eye.
These thin lenses are implanted permanently into the eye to help reduce the need for glasses or contact lenses. The lens is made of plastic or silicone that is implanted into the eye permanently to reduce a person’s need for glasses or contact lenses. Phakic refers to the fact that the lens is implanted into the eye without removing the eye’s natural lens. During phakic lens implantation surgery, a small incision is made in the front of the eye. The phakic lens is inserted through the incision and placed just in front of or just behind the iris.
Phakic intraocular lenses are indicated for patients with high refractive errors when the usual laser options for surgical correction (LASIK and PRK) are contraindicated. Phakic IOLs are designed to correct high myopia ranging from −5 to −20 D if the patient has enough anterior chamber depth (ACD) of at least 3 mm.
PIOLs vs. Laser Surgery
Both PIOL and laser surgery have their share of advantages and disadvantages.
- PIOLs have the advantage of treating a much larger range of myopic and hyperopic refractive errors than can be safely and effectively treated with LASIK in terms of both postoperative visual acuity and contrast sensitivity.
- The Phakic procedure is quick – typically about 15 minutes per eye – but it cost a little more as compared to laser surgery.
- The PIOL is removable; therefore, the refractive effect should theoretically be reversible. However, any intervening damage caused by the PIOL would most likely be permanent. When compared with clear lens extraction, or refractive lens exchange the PIOL has the advantage of preserving natural accommodation and may have a lower risk of postoperative retinal detachment because of the preservation of the crystalline lens and minimal vitreous destabilization.
- In case of Phakic lens surgery, patients usually put in eye drops for two to three weeks, compared with a week to 10 days of drops after laser surgery.
- PIOL insertion is an intraocular procedure. With all surgeries there are associated risks. In addition, each PIOL style has its own set of associated risks. In the case of PIOLs made of polymethylmethacrylate (PMMA), surgical insertion requires a larger incision, which may result in postoperative astigmatism. By comparison, PIOLS made of collamer (a foldable gel-like substance) requires a very small incision due the flexibility of the material and thus significantly reduces astigmatism risk. In the cases where refractive outcomes are not optimal, LASIK can be used for fine-tuning. If a patient eventually develops a visually significant cataract, the PIOL will have to be explanted at the time of cataract surgery, possibly through a larger-than-usual incision.
If you are considering Phakic lens surgery, look for an eye surgeon who has done a number of the procedures already.
