All About Cataracts

In addition to improving vision and quality of life for seniors with cataracts, cataract surgery also appears to reduce the number of auto accidents involving older people, according to a new study.

At the 2010 Joint Meeting of the American Academy of Ophthalmology (AAO) and Middle East-Africa Council of Ophthalmology (MEACO), Jonathan Ng, MD, presented the results of a study of auto accident rates among Australians with cataracts in both eyes before and after cataract surgery on their first eye.

A total of 27,827 patients age 60 and older who had cataract surgery between 1997 and 2006 were included in the study.

Data from the Western Australian Road Injury Database was obtained for all patients in the study to identify those who had been involved in a motor vehicle accident up to 12 months prior to and 12 months following their cataract surgery.

“We found cataract surgery reduced the frequency of all crashes by 12.6 percent,” Dr. Ng said in a press release issued by the AAO. The study also revealed that a majority of patients involved in automobile accidents were males between the ages of 70 and 79 who lived in metropolitan areas.

The study authors noted that in Australia and other countries, patients often have to wait weeks or months after cataracts are diagnosed to undergo cataract surgery. This study suggests that significant delays in obtaining cataract surgery affect not only the patients’ quality of life, but individual and public safety as well, they say.

The authors also say that additional research is needed to compare auto accident rates before and after cataract surgery with intraocular lens implantation on the patients’ second eye.

A new Veterans Health Administration study confirms the safety of cataract surgery, finding a low mortality rate 90 days after the procedure, even among high-risk patients.

Researchers at the VA Medical Center and at Warren Alpert Medical School of Brown University (both in Providence, Rhode Island) evaluated 45,082 patients in the National Patient Care Database who had significant cataracts and who underwent outpatient cataract surgery at VA hospitals between October 2005 and September 2007. Mean patient age was 71.8 years, 97.6 percent of patients were men and the postoperative follow-up period was 90 days.

The most frequent systemic health problems among the patients in the study were diabetes (40.6 percent), chronic pulmonary disease (21.2 percent), cancer (12.5 percent) and congestive heart failure (9.5 percent).

The study data revealed the mortality rate within 90 days after cataract surgery was 7.1 per 1,000 patients (0.7 percent).

Independent risk factors for mortality within the 90-day follow-up period were patient age of 80 years or greater, one or more hospitalizations within the past year, chronic pulmonary disease, cirrhosis, multiple myeloma, leukemia and metastatic solid tumor.

The study authors concluded the risk of mortality within 90 days after cataract surgery is low, even for high-risk patients such as the elderly and those with significant preoperative systemic diseases.

A full report of the study appears in this month’s issue of Ophthalmology.

Though people who are highly nearsighted have a greater risk of a developing a detached retina than the general population, cataract surgery doesn’t add to that risk.

That’s the finding of a large-scale study presented at the World Ophthalmology Congress held last month in Berlin.

Irmingard Neuhann, MD, who practices at Tuebingen University Eye Hospital in Germany, reported the results of a retrospective study of 1,519 consecutive patients with high myopia that underwent modern phacoemulsification cataract surgery. The surgery was performed on a total of 2,356 eyes that had an axial length greater than 27 millimeters.

Axial length is the distance between the front surface of the eye (cornea) and the back of the eye (retina), usually measured in millimeters (mm).

A normal adult eye typically has an axial length of approximately 24 mm. Eyes with axial length greater than 24 mm usually are nearsighted, and each additional millimeter corresponds to approximately -2.50 diopter (D) of myopia. Therefore, an axial length greater than 27 mm typically corresponds to myopia of -7.50 D or more.

The incidence of retinal detachment following cataract surgery among the eyes in the study was approximately 2 percent, according to Dr. Neuhann. The patients were followed for a period of 2 years.

Though this rate is higher than the rate of detached retina among the general population, no large study has ever demonstrated that this rate is different than that of spontaneous retinal detachment in nearsighted individuals with eyes of comparable axial length, she said.

High myopia associated with increased axial length of the eye is believed to be a risk factor for retinal detachment because, as the eye elongates during development, the peripheral retina becomes thinner and more fragile in these longer-than-normal eyes.

[Resource: Cataract surgery not a risk factor for retinal detachment in highly myopic eyes, study says. Published online June 8, 2010 on Ocular Surgery News website.]

Thankfully, congenital cataracts are relatively rare. But when a baby is born with cataracts, prompt treatment is essential to insure normal infant vision development and prevent permanent vision loss from amblyopia.

Performing cataract surgery on an infant poses special challenges to cataract surgeons. Also, an often-debated question is whether the best treatment for the young, developing eyes of an infant after cataract removal is implantation of an intraocular lens (IOL) or the use of contact lenses.

To answer this question, Scott R. Lambert, MD, at Emory University (Atlanta, Ga.) and other members of the multi-center Infant Aphakia Treatment Study Group conducted a study of the two treatment options.

The researchers compared the visual outcomes and adverse events among 114 infants with congenital cataracts who underwent cataract surgery at an average age of 1.8 months. The infants were randomly assigned to either be treated with an IOL (57 infants) or with contact lenses (57 infants).

Results of the study revealed that surgical complications occurred in 28 percent of infants in the IOL group and 11 percent of those in the contact lens group.

At 1 year of age, visual acuity results were equal in the two groups, but more infants in the IOL group (77 percent) experienced adverse events after surgery, compared with 25 percent in the contact lens group.

Infants in the IOL group also were five times more likely to undergo additional eye surgery (63 percent compared with 12 percent in the contact lens group).

“There appears to be no short-term visual benefit and some increased risk to implanting intraocular lenses in infants,” the researchers concluded. But they also said it is “premature to recommend that intraocular lenses not be implanted in infants” and that a longer a follow-up period is needed to clarify the role of IOLs in the treatment of congenital cataracts.

A full report of the study will appear in the July 2010 print issue of Archives of Ophthalmology.