All About Cataracts

Modern cataract surgery may have long-term benefits for people with glaucoma and ocular hypertension, according to a new study.

Researchers in Arkansas, Washington and Utah reviewed the medical charts of 266 non-glaucoma patients who underwent phacoemulsification (or “phaco”) cataract surgery to evaluate both short-term and long-term changes in IOP after cataract removal with intraocular lens (IOL) implantation.

Elevated IOP is a risk factor for glaucoma. Lowering IOP may reduce a person’s risk of developing the disease.

All cataract extractions were performed using a technique called “temporal clear corneal phacoemulsification,” in which a small incision is created in the peripheral cornea and an ultrasonic probe is inserted through the opening. This probe breaks the cataract into small pieces so it can be removed more easily.

IOP measurements were taken with a Zeiss Humphrey IOLMaster (Carl Zeiss Meditech), a non-contact automated device, prior to surgery and 1 day, 1 week, 3 months, 6 months, 1 year and 2 years after surgery.

The researcher found that phaco cataract surgery produced both short-term and long-term reductions of IOP, compared with pre-operative measurements. Mean reduction of IOP was:

• 8.2 percent at 3 months
• 4.6 percent at 6 months
• 6.7 percent at 1 year
• 7.8 percent at 2 years

The authors of the study concluded that temporal clear corneal phacoemulsification cataract surgery results in a decrease in intraocular pressure that persists for at least two years following surgery.

SOURCE: Intraocular pressure change after temporal clear corneal phacoemulsification in normal eyes. Acta Ophthalmologica. February 2010.

If you have cataracts and also are being treated for glaucoma, cataract surgery may reduce your need for glaucoma medications and surgery, according to a new study.

Researchers in Korea recently conducted a retrospective study of 96 people with glaucoma who underwent phacoemulsification cataract surgery with intraocular lens (IOL) implantation for the treatment of clinically significant cataracts. Forty-eight of the patients had primary open-angle glaucoma (POAG) and 48 had primary angle-closure glaucoma (PACG).

While previous studies have shown that cataract extraction with IOL implantation lowers intraocular pressure (IOP) in patients with and without glaucoma, the focus of this study was to determine which type of glaucoma patients are most likely to achieve the greatest IOP-lowering effect of cataract surgery.

The follow-up period ranged from 24 to 54 months, with a mean of 31 months.

The researchers found that cataract surgery successfully controlled the IOP of 39.6 percent of eyes with POAG and 62.5 percent of eyes with PACG. The criteria of success was attaining an IOP of 21 mm Hg or lower without medical glaucoma treatment or with fewer anti-glaucoma medications than before surgery.

Among eyes with primary open-angle glaucoma, pre-operative factors increasing the likelihood of successful IOP control after cataract surgery were a maximum IOP lower than 31 mm Hg and use of fewer than three anti-glaucoma medications.

Pre-operative factors increasing the likelihood of success among eyes with primary angle-closure glaucoma were a maximum IOP lower than 42 mm Hg, use of fewer than three anti-glaucoma medications and less than 30 percent of the drainage angle of the anterior chamber of the eye being affected by iris adhesions called peripheral anterior synechiae.

The researchers concluded that modern small-incision cataract surgery using phacoemulsification and foldable IOL implantation may help control IOP in some glaucoma patients, reducing or eliminating their need for anti-glaucoma medicine and/or glaucoma surgery.

The study was published in this month’s issue of Canadian Journal of Ophthalmology.