All About Cataracts

New research suggests it is safe to perform cataract surgery using topical anesthesia and intravenous sedation without requiring patients to fast prior to surgery.

Fasting before cataract surgery is a long-standing precautionary practice. Doing so allows the stomach to empty prior to surgery, reducing the risk of the patient aspirating contents of their stomach into their lungs when medications are given that may reduce the body’s normal protective mechanisms.

Aspiration of stomach contents during surgery can cause aspiration pneumonia, a potentially serious cataract surgery complication.

But there also are risks associated with fasting, particularly for people with diabetes.

Canadian researchers at the Department of Ophthalmology and Visual Sciences, University of British Columbia and the Department of Anesthesia, Providence Health Care (Vancouver, B.C.) performed a retrospective study of more than 5,000 cases of cataract surgery performed at Mount St. Joseph Hospital (Vancouver) between April 2007 and March 2008.

Nearly all of the cataract removal procedures (97 percent) were performed using only topical anesthesia. A small minority (3 percent) required additional anesthesia injected behind or around the eye to prevent eye movements during surgery.

Approximately 50 percent of patients received intravenous (IV) sedation for the cataract procedure, as deemed appropriate by the attending medical staff.

All patients in the study were allowed to eat and drink freely until they arrived at the hospital, approximately one hour prior to their cataract removal.

Results of the study, published in this month’s issue of Canadian Journal of Ophthalmology, indicate that there were no cases of aspiration pneumonia among the 5,125 non-fasting cataract surgery patients in the study.

The authors concluded that it is safe to perform cataract surgery under topical anesthesia and intravenous sedation without requiring patients to fast prior to surgery.

People who have cataract surgery before age 65 appear to have a greater risk of clouding of the eye tissue directly behind the intraocular lens (IOL) that can lead to vision loss, according to a Swedish study.

The good news is that vision loss from this cataract surgery complication — called a posterior capsule opacity (PCO) — usually can be restored with a simple laser procedure called a ND:YAG laser capsulotomy.

Researchers at Norrlands University Hospital in Umea, Sweden, compared the vision of 116 patients who had cataract surgery prior to age 65 with the post-operative vision of patients age 65 and older at the time of surgery. Ten years after cataract surgery, 102 of the 116 people in the study group were given an eye exam and were asked to complete a questionnaire about their vision.

Analysis of the data revealed that within 10 years of cataract surgery, 37 percent of those younger than age 65 at the time of surgery experienced PCO and underwent a ND:YAG laser capsulotomy to restore their vision. In comparison, only 20 percent of those who were 65 or older at the time of cataract surgery required the laser procedure afterward.

The researchers concluded that more than one-third of patients in this study who were under age 65 at the time of cataract surgery subsequently developed a posterior capsule opacity that required a laser capsulotomy to restore vision.

Secondarily, the researchers said that 10 years after surgery, subjective visual function (measured with a questionnaire) and objective visual acuity (measured with an eye chart) remained stable in most patients who had cataract surgery when they are younger than age 65.

SOURCE: Ten-year longitudinal vision function and ND:YAG laser capsulotomy rates in patients less than 65 years at cataract surgery. American Journal of Ophthalmology. Published online November 18, 2009.

Bausch & Lomb (Rochester, N.Y.) recently announced the U.S. launch of its new Akreos MICS lens, a foldable intraocular lens (IOL) designed for implantation through a 1.8 mm incision during phacoemulsification cataract surgery.

The ability to insert the new acrylic lens through such a small incision offers several potential advantages, including faster healing and less surgically-induced astigmatism, according to the company.

The lens also features aspheric optics designed to reduce spherical aberration and produce excellent post-operative vision. (Spherical aberration is a common higher-order aberration that can degrade vision and cause glare and halos around lights.)

The new Akreos IOL represents a new level of micro-incision cataract surgery (MICS). With most other IOLs used in MICS, an incision of 2.2 mm to 2.75 mm is required.

Prior to phacoemulsification technology, incision sizes of 10 mm or greater were common in cataract surgery, with greater risks of eye infection, delayed healing and other cataract surgery complications.

Because the Akreos MICS lens is a premium IOL, it may increase your cataract surgery cost if you choose this implantable lens for your surgery.

The Akreos MICS is the latest addition to Bausch & Lomb’s Akreos line of IOLs. First introduced in Europe over 10 years ago, more than 3 million Akreos IOLs have been implanted worldwide, according to the company.

People with diabetes who undergo cataract surgery have twice the risk of progression of their diabetic retinopathy, according to a new study.

Researchers at the University of Sydney (New South Wales, Australia) and the University of Melbourne (Victoria, Australia) followed 190 diabetic patients age 65 and older who underwent phacoemulsification cataract surgery between 2004 and 2006. Of the 190 patients, 169 were followed for at least 12 months after surgery.

During the 12-month follow-up period, diabetic retinopathy (DR) developed in 28.2 percent of eyes that underwent cataract surgery with intraocular lens (IOL) implantation and did not have DR prior to surgery. During the same 12-month period, diabetic retinopathy developed in 13.8 percent of eyes that did not undergo cataract surgery and did not have DR at the beginning of the study period.

In a paired-eye comparison of 45 patients with pre-existing diabetic retinopathy who had cataract surgery in one eye but not the other and were at risk of DR progression, 35.6 percent of the post-surgical eyes exhibited progression of diabetic retinopathy, compared with 20 percent of the fellow eyes that did not undergo surgery.

The researchers concluded that people with diabetes who undergo modern phacoemulsification cataract surgery appear to have twice the risk of developing diabetic retinopathy or experiencing a progression of their DR  12 months after surgery.

This added risk, however, is lower that the risk of diabetes-related cataract surgery complications that has been previously documented in diabetic patients who have undergone less advanced cataract surgery (”intracapsular” and “extracapsular” cataract surgery without phacoemulsification).

Source: Development and progression of diabetic retinopathy 12 months after phacoemulsification cataract surgery. Ophthalmology. August 2009.