Cataract surgery aids low vision

Key Points

Baltimore-Cataract surgery can be beneficial in patients with low vision. However, thorough preoperative counseling and discussion of patient expectations are absolutely necessary, according to the results of a small pilot study presented by Irene C. Kuo, MD. She spoke here at the 24th annual meeting of Current Concepts in Ophthalmology, held in association with Ophthalmology Times.

"We are doing 1.7 million cataract extractions in Medicare beneficiaries annually, and the expected volume of surgery will only increase as we expect an increase of patients 85 years or older in the next 25 years," said Dr. Kuo, associate professor of ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore. "We should also expect that these people will have concomitant age-related visual impairment, such as age-related macular degeneration (AMD) and glaucoma."

All patients were referred to one surgeon (Dr. Kuo) from a low vision clinic for surgical evaluation. Visual acuity and responses to an extensive 23-page survey were compared preoperatively and at 3 months postoperatively. These questions included self-reported functioning, general vision, and patients' ability to see.

As an example, general vision questions included:

Regarding mobility, patients were asked about activity in familiar and unfamiliar areas, climbing stairs, seeing things to the side, and crossing streets.

Patients were also questioned about illumination and how well they saw indoors, outdoors, with different illumination levels; reading, writing, and doing other close work at normal light levels; seeing with glare from headlights; working in dim light after being in bright light; and the ability to see faces at 3 feet. Snellen acuity testing was done in Dr. Kuo's office and converted to logMAR scales.

In all, 30 patients were referred to Dr. Kuo, 22 consented to surgery, and 20 underwent surgery. All had nuclear sclerotic cataracts graded at least 3+, with visual acuity expected to be less than 20/40 if no ocular comorbidities existed.

Dr. Kuo went through lengthy preoperative preparation and counseling with patients and families. All patients underwent uncomplicated surgery with IOL implantation (SA60AT, Alcon Laboratories), with a target refraction of plano. The majority of patients (75%) had AMD. Mean age was 78 years, and ranged from 53 to 96 years.

Preoperative visual acuity ranged from 20/70 to counting fingers, and improved to 20/40 to 20/400. The average change in best-corrected visual acuity (BCVA) was 0.6 logMAR, about 3 lines from the ETDRS scale (p = 0.0001). BCVA improved in 25 (83%) of eyes in 15 patients, and was unchanged in 5 eyes of 5 patients, 1 with rod-cone dystrophy, and 4 with AMD. As a surrogate measure of safety, no patient lost BCVA. Four patients could read with a magnifier after surgery, and on average, self- reported functioning improved, Dr. Kuo said.

Dr. Kuo noted that she and her colleagues did one thing differently in this study that most other studies did not.

"What separates this study from some others is that I elicited patient comments about their experience," she said. "A full 85% of patients said they would consent to the surgery again if given the option. They noted improvements in visual acuity, quality, color perception, subjective contrast sensitivity, and ability to navigate in unfamiliar surroundings.