This article is from September 2011 and may contain outdated material.
Monovision Trumps Multifocal IOLs
A recent study provides more support for pseudophakic monovision in this era of presbyopiacorrecting IOLs. In the first prospective comparative study of a diffractive multifocal IOL (AcrySof ReStor) and a traditional monofocal IOL (AcrySof SN60WF) in bilateral cataract patients, the monovision patients had significantly better intermediate vision, less difficulty using computers without glasses and more favorable scores for driving at night and in difficult conditions.1
The 22 monovision patients also did well on gross depth perception and stereo vision, although fine stereo vision was better in the multifocal group. In addition, significantly more of the 21 multifocal patients reported symptoms such as halo and glare. Near and distance vision outcomes were comparable for the two groups. Overall, the monovision patients had higher satisfaction levels than the multifocal IOL patients.
A second study of the same patient cohorts evaluated quality-of-life markers, spectacle independence and visual function three months after surgery. Both groups reported significant improvement in all areas surveyed, noting that they were much less worried about their vision and felt more confident about their ability to read, drive, see signs and go up and down stairs.2
“Monovision is still one of the most effective methods for the management of presbyopia, if it is done appropriately. It costs much less than any of the present premium IOLs, but patients’ visual function may not be necessarily inferior at all,” said lead author Fuxiang Zhang, MD, senior staff ophthalmologist at the Henry Ford Medical Center in Taylor, Mich.
In addition, he said, “Monovision has fewer significant side effects; and in the worst-case scenario, it can be reversed just by wearing glasses and does not require IOL exchange.” He added that of his more than 1,000 pseudophakic monovision patients, not one has expressed dissatisfaction with the procedure, while two of “several hundred” multifocal patients have discussed with him the possibility of an IOL exchange.
The two studies were not randomized primarily because of cost issues and patient preference, Dr. Zhang said. In addition, it took him two years to compile enough bilateral sequential cases for evaluation. “I am a moderately busy general ophthalmologist. Most of my cataract patients did not mind wearing glasses after surgery, so they were not offered for inclusion,” he said. “I also excluded a good percentage of patients who did not want to have cataract surgery on the second eye, as they did not feel the second eye was affecting their visual function.”
Patients also were excluded if they had significant ocular disease (such as diabetic retinopathy or macular degeneration), severe connective tissue disease (if a limbal relaxing incision would be required for astigmatism) or a mesopic pupil of 5 mm or larger, he said.
Dr. Zhang noted that he discusses the wide range of current options with every cataract patient who wants to be free of glasses. “Depending on each patient’s lifestyle and hobbies, I will give my recommendation. Among all the options, monovision seems to be the most commonly used. It certainly plays a significant role in the battle with presbyopia among cataract patients at this time when we still do not have a perfect solution.”
1 Zhang, F. et al. J Cataract Refract Surg 2011;37(3):446–453.
2 Zhang, F. et al. J Cataract Refract Surg 2011;37(5):853–858.
Dr. Zhang reports no related financial interests.
NSAIDs & Cataract Surgery
The Academy’s recent survey of comprehensive ophthalmologists revealed a strong preference for the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in cataract patients. Threefourths of those surveyed prescribe or recommend NSAIDs for all cataract patients, while nearly a quarter use them only in patients at higher risk for developing pseudophakic cystoid macular edema (CME).
Douglas D. Koch, MD, professor of ophthalmology at Baylor College of Medicine in Houston, said, “This is a much higher utilization of nonsteroidals in routine cataract surgery than we saw several years ago.”
But he is not entirely surprised by the results. Several factors might have contributed to this shift. First, some studies now support the clinical benefits of NSAIDs in routine cases. “Prior to recent studies, data primarily showed a difference in angiographic CME,” he said. “But randomized studies have subsequently shown a reduction in clinically significant CME. And other studies have shown that, on average, retinal thickness as measured by OCT is thinner in eyes treated with nonsteroidals.” 1
These studies have prompted a change in practice, especially when they are combined with the increased marketing by pharmaceutical companies, influence of opinion leaders, and high demand of patients for a quick and complete recovery after cataract surgery, he said.
NSAIDs also have a mild anesthetic effect, reducing incisional sensation and irritation on the ocular surface, said Dr. Koch. “I continue to be impressed by how important it is for patients to have their eyes feel and look good after surgery,” he said, explaining that this reassures patients that they’ve undergone a gentle procedure.
Like the majority of those surveyed, Dr. Koch also uses NSAIDs for all his cataract cases, and he has been doing so for years. His main reason for using NSAIDs is CME, even though it is a rare occurrence. Dr. Koch’s regimen begins one day before surgery and continues for about two weeks after surgery. He extends treatment to about four weeks for patients at higher risk, including those who had CME in the first eye after routine surgery or have retinal pathology predisposing them to CME, such as diabetic retinopathy or epiretinal membrane.
However, because corneal melting has been reported in association with topical NSAIDs, Dr. Koch advises caution in using them for patients with significant ocular surface disease, particularly if treatment is continued beyond a week or two.
Dr. Koch is a consultant for Alcon.
1 Whittpenn, J. et al. Invest Ophthalmol Vis Sci 2007;48:EAbstract 5464.
Vegetarians See Drop in Cataract Risk
Eating less meat appears to provide protection against cataract development, British researchers report.1
The finding emerged as an unexpected benefit in one of the British arms of the long-running EPIC (European Prospective Investigation into Cancer and Nutrition) study.
“The EPIC-Oxford cohort was set up to include a high proportion of nonmeat eaters, and the authors have a particular interest in the long-term health of vegetarians and vegans,” said lead author Paul N. Appleby, senior statistician at the University of Oxford’s cancer epidemiology unit. “The availability of hospital admissions data for study participants enabled us to investigate the associations between diet group and a large number of diseases and other causes of hospitalizations, and we were struck by the association with cataract risk.”
The EPIC-Oxford cohort includes more than 60,000 men and women. In this study, the researchers evaluated 27,670 participants, excluding those who were younger than age 40, had diabetes or a malignant cancer, had unknown smoking habits, had incomplete or inconsistent dietary data, or did not live in England or Scotland (the two countries for which hospital admissions data were available).
The participants were then characterized as meat eaters, fish eaters (who ate fish but no meat), vegetarians or vegans. In addition, the meat eaters were further characterized according to their consumption levels as high-, medium- or low-meat eaters (consuming at least 3.5 oz per day, 1.7 to 3.4 oz per day or less than 1.7 oz per day, respectively).
The results: There was a progressive decrease in cataract risk, with those who ate the most meat experiencing the greatest risk of developing cataracts and vegetarians and vegans the lowest. Fish eaters were 21 percent less likely to develop a cataract than high-meat eaters, and vegetarians and vegans were 30 and 40 percent less likely, respectively.
1 Appleby, P. N. et al. Am J Clin Nutr 2011;93(5):1128–1135.
Asian-Americans: High Risk of OAG, NTG and NAG
Open-angle glaucoma (OAG) occurred 50 percent more frequently in Asian-Americans than in non-Hispanic whites in a recent study by researchers at the University of Michigan, Ann Arbor, involving a large, nationwide sample.1 This finding is somewhat surprising because previous studies have suggested that OAG, which is the most common type of glaucoma in the United States, was relatively uncommon in people of Asian descent, the authors note.
The finding emerged from a study to determine the rates of various types of glaucoma by race and ethnicity, with a special focus on Asian-Americans. “Although there has been an informal consensus in the glaucoma community that Asian-Americans have higher rates of certain forms of glaucoma, these speculations had not, until now, been confirmed or quantified in a large-scale study,” said lead investigator Joshua D. Stein, MD, MS, who analyzed data from a group of 2,259,061 eye care recipients aged 40 and older.
The likelihood of developing normal tension glaucoma (NTG) and narrowangle glaucoma (NAG) also was much higher for Asian- Americans (159 percent and 123 percent, respectively) when compared with their non-Hispanic white counterparts. But NTG and NAG appear to affect Asian-American ethnicities differently. For example, said Dr. Stein, “we found much higher rates of NTG among Japanese-Americans, whereas Chinese-Americans exhibited much higher rates of NAG.
“We have long recognized that African-Americans have higher rates of glaucoma than whites. Based on these study findings, eye care providers should have a high index of suspicion for glaucoma in Asian-Americans as well.” When examining Asian- American patients, Dr. Stein and his colleagues advocate that ophthalmologists should carefully evaluate the optic nerve and, when appropriate, perform visual field testing. The threshold for performing gonioscopy should be low in patients of certain Asian ethnic groups, including Chinese- and Vietnamese-Americans. Moreover, although elevated IOP often alerts eye care providers to a higher glaucoma risk, this risk factor may not be present in some Japanese-Americans, who may nonetheless be at increased risk for glaucomatous damage to the optic nerve and loss of peripheral vision. Dr. Stein said that future studies will need to explore the genetic and environmental factors contributing to differences in the rates of specific forms of glaucoma among Asian-American ethnic groups.
1 Stein, J. D. et al. Ophthalmology 2011;118(6):1031–1037.