COMANAGEMENT Q&A

Phakic IOLs:
Coming to an Eye Near You

Edited by Paul C. Ajamian, O.D.

Question: Who's a candidate for the forthcoming phakic IOLs?

Answer:    In general, a candidate for a phakic IOL is anyone who isn't a good candidate for corneal refractive surgery. This includes patients with high myopia, thin corneas, keratoconus or previous RK surgery, according to optometrists Robert Pinkert and Marc Bloomenstein of Barnet Dulaney Eye Center in Phoenix.

Drs. Pinkert and Bloomenstein are involved in two phakic IOL studies, one for myopes and the other for hyperopes. They're helping to investigate Staar Surgical's Implantable Contact Lens (ICL), a posterior chamber IOL. In a procedure similar to cataract surgery, the ICL fits behind the iris but in front of the crystalline lens.

The other two major phakic IOL designs are placed in the anterior chamber. One design is supported with haptics at the angle. The Baikoff lens being developed by Bausch & Lomb is the most prominent example. The other design, the Artisan lens by Ophtec USA, has haptics that clutch the iris stroma.

Question:  Is a phakic IOL a viable alternative to LASIK?

Answer:  It's an option with at least one advantage over LASIK. "I think a deciding factor in this procedure is that it's reversible," Dr. Bloomenstein says. "When you have a procedure as permanent as LASIK or PRK, you don't have a safety net. This procedure doesn't have that finality." Patients can have the phakic IOL removed if the outcome is less than optimum.

Another advantage may be optical quality. At least with the posterior chamber ICL, "The quality of the vision is likely to be better [than LASIK] because you're not changing the natural asphericity of the cornea, which some people believe leads to some of the visual side effects of corneal refractive surgery," Dr. Pinkert says. Investigators for the other two lens designs did report glare and/or halos, but redesigns aim to minimize these problems.

Dr. Pinkert was so impressed with the optical quality of the phakic IOL, he offered it as an option to his wife, Jodi, who had been wearing contact lenses for more than 30 years. Now two months post-op, Ms. Pinkert is pleased with her outcome and doing well.

There are some precautions with phakic IOL procedures. The risks are on par with those of cataract or refractive surgery: potential for anterior capsule rupture or infection, endothelial cell loss, glaucoma, cataract formation, chronic iritis and potential endophthalmitis.

When inserting the posterior chamber ICL, the surgeon must be cautious not to touch the crystalline lens. The surgeon must vault the ICL high enough above the crystalline lens to ensure that they don't touch later, which would create a cataract. (No participant in the Barnet Dulaney Eye Center study has had a visually significant cataract yet, Dr. Pinkert notes.)

Be aware that for both the ICL and the Artisan lens, patients require a peripheral iridotomy before lens insertion. This prevents an angle closure in case the aqueous is blocked during the implantation. Also, patients receiving an IOL in the anterior chamber require pre-op measurements for axial length and anterior chamber depth. These important readings determine if the anterior chamber has enough space to accommodate the implant—a problem for hyperopes who have shallow chambers.

What's involved in post-op care?
"O.D.s who are familiar with comanaging cataract and refractive patients should have no difficulty transitioning to the comanagement of these patients," Dr. Pinkert says. Put these patients on a steroid-antibiotic combination drop for several weeks after surgery. Monitor IOP, vision and refraction as you would for cataract or LASIK patients.

One note for the posterior chamber ICL: Assess the height of the vault through the slit lamp. Make sure the implant doesn't touch the crystalline lens.

The current investigational phakic IOLs aren't for astigmats. But upcoming studies with toric lenses should soon change that. Meanwhile, investigators expect phakic IOLs to be approved within the next two years.