MyVisionTest News Archive
Feb 10, 2009
AREDS: Cataract surgery does not increase the risk of advanced AMD
The AREDS study finds that there is no clinically important increased risk of progression to advanced AMD after cataract surgery.
Concerns have been raised regarding the potential of cataract surgery to accelerate progression to advanced, vision-threatening forms of AMD. Largely because of the findings from two large epidemiologic studies of an adverse association of cataract surgery with AMD, some investigators have speculated on the risk of cataract surgery in eyes at risk for development of advanced AMD.
The investigators analyzed the relationship between cataract surgery and the development of advanced AMD (neovascular or geographic atrophy) in 4577 participants (8050 eyes) from the Age-Related Eye Disease Study (AREDS), a multicenter, controlled, randomized clinical trial. Development of advanced AMD was evaluated with annual fundus photographs, and history of cataract surgery was assessed every 6 months.
A Cox proportional hazards model of right eyes showed non-significant hazard ratios of 1.20 (95% confidence interval [CI], 0.82–1.75) for NV AMD, 0.80 (95% CI, 0.61–1.06) for GA, and 0.87 (95% CI, 0.64–1.18) for central GA (CGA). Similar results were obtained for left eyes. For participants with advanced AMD in 1 eye (AREDS category 4), the hazard ratios for fellow eyes were 1.08 (95% CI, 0.65–1.72) for NV AMD and 0.98 (95% CI, 0.64–1.49) for CGA.
Results from the Cox models are not statistically significant and there are no consistent trends among models. The absence of any consistent pattern in the direction of harm across models reinforces the conclusion that AREDS data provide little evidence that cataract surgery increases the risk of progression to late AMD.
These results are contrary to the results of some previously published epidemiologic studies, including 2 reports that each pooled data from different population-based studies. Combined cross-sectional data from the Salisbury Eye Evaluation, Proyecto VER (Project Vision, Evaluation, Research), and the Baltimore Eye Survey found that “a history of cataract surgery may be associated with an increased prevalence of late AMD” (OR, 1.7; 95% CI, 1.1–2.6).
A second population-based study pooled the 5-year results of the Beaver Dam Eye Study and the Blue Mountains Eye Study. They identified persons with and without a history of cataract extraction at a baseline examination and reexamined them for incident AMD at 5 and 10 years. They found an association between cataract surgery and the 5-year incidence of late AMD (NV AMD and GA) with an adjusted OR of 5.7 (95% CI, 2.4 –13.6). Analyses after 10 years of follow-up showed that the relationships largely persisted.
There are many differences between the AREDS study and earlier studies that found an association between cataract surgery and progression of AMD. For example, AREDS participants were selected on the basis of having a high risk of developing advanced AMD. More than 40% of the AREDS cohort had high-risk characteristics for late AMD - at least 1 large druse, extensive intermediate drusen, or GA that did not involve the center of the macula. The inclusion of such a high proportion of participants who had a propensity for advanced AMD to develop might have decreased the ability to detect additional risk factors, such as the impact of cataract surgery.
Another factor that might have resulted in differences between these results and those from the earlier population-based studies is the period in which the cataract surgery was conducted. Techniques in cataract surgery and types of lens implants have changed over time. AREDS participants, with their more recent surgery, were probably more likely to have had ultraviolet B-blocking lens implants inserted than persons who had lenses implanted earlier. Some have hypothesized that insertion of such lenses may decrease the risk of AMD by blocking ultraviolet B exposure of the macula. Thus, the greater likelihood of extracapsular cataract extractions with insertion
of ultraviolet-blocking lenses in AREDS participants may explain some of the differences in findings.
In the AREDS population it seems that cataract surgery was not associated with a clinically important increase in the rates of development of advanced AMD. Persons with intermediate AMD (bilateral large drusen) or with unilateral advanced AMD should be aware of the fact that the risk of developing advanced AMD is as high as 50% in 5 years, regardless of cataract surgery. Although the results of AREDS analyses suggest that this risk does not seem to be accelerated by cataract surgery, the patient still should be counseled as to the risk of development of advanced AMD because of the natural course of the disease.
In summary, the AREDS data suggest that there is no clinically important increased risk of progression to advanced AMD after cataract surgery. This is the only prospective study in which the severity of AMD was documented before and after cataract surgery in a large number of cases with more than 5 years of regular follow-up. These data, which are contrary to that of previously reported results, may provide some reassurance to patients with AMD who are considering cataract surgery.
WHAT IT MEANS TO YOU: Concerns surrounding the role of sunlight in the development of AMD has lead to increase speculation that cataract surgery, with its resultant increase in macular sunlight exposure, may increase the risk of AMD. Earlier research, which suggested an increased risk of AMD progression following cataract extraction, has helped to fuel this speculation. But AREDS has clearly demonstrated that cataract surgery as it is being performed today does not increase the risk of AMD progression. This begs the question whether there is a need for blue-blocker intraocular lenses to protect the macula. If cataract surgery with UV-blocking does not place the macula at-risk for AMD progression, then blue-blocker IOLs may not provide any clinically important additional benefit.
Read more...
Ophthalmology. 2009 Feb;116(2):297-303. Epub 2008 Dec 16.
Tags: AMD, cataract, AREDS
The AREDS study finds that there is no clinically important increased risk of progression to advanced AMD after cataract surgery.Concerns have been raised regarding the potential of cataract surgery to accelerate progression to advanced, vision-threatening forms of AMD. Largely because of the findings from two large epidemiologic studies of an adverse association of cataract surgery with AMD, some investigators have speculated on the risk of cataract surgery in eyes at risk for development of advanced AMD.
A Cox proportional hazards model of right eyes showed non-significant hazard ratios of 1.20 (95% confidence interval [CI], 0.82–1.75) for NV AMD, 0.80 (95% CI, 0.61–1.06) for GA, and 0.87 (95% CI, 0.64–1.18) for central GA (CGA). Similar results were obtained for left eyes. For participants with advanced AMD in 1 eye (AREDS category 4), the hazard ratios for fellow eyes were 1.08 (95% CI, 0.65–1.72) for NV AMD and 0.98 (95% CI, 0.64–1.49) for CGA.
Results from the Cox models are not statistically significant and there are no consistent trends among models. The absence of any consistent pattern in the direction of harm across models reinforces the conclusion that AREDS data provide little evidence that cataract surgery increases the risk of progression to late AMD.
These results are contrary to the results of some previously published epidemiologic studies, including 2 reports that each pooled data from different population-based studies. Combined cross-sectional data from the Salisbury Eye Evaluation, Proyecto VER (Project Vision, Evaluation, Research), and the Baltimore Eye Survey found that “a history of cataract surgery may be associated with an increased prevalence of late AMD” (OR, 1.7; 95% CI, 1.1–2.6).
A second population-based study pooled the 5-year results of the Beaver Dam Eye Study and the Blue Mountains Eye Study. They identified persons with and without a history of cataract extraction at a baseline examination and reexamined them for incident AMD at 5 and 10 years. They found an association between cataract surgery and the 5-year incidence of late AMD (NV AMD and GA) with an adjusted OR of 5.7 (95% CI, 2.4 –13.6). Analyses after 10 years of follow-up showed that the relationships largely persisted.
There are many differences between the AREDS study and earlier studies that found an association between cataract surgery and progression of AMD. For example, AREDS participants were selected on the basis of having a high risk of developing advanced AMD. More than 40% of the AREDS cohort had high-risk characteristics for late AMD - at least 1 large druse, extensive intermediate drusen, or GA that did not involve the center of the macula. The inclusion of such a high proportion of participants who had a propensity for advanced AMD to develop might have decreased the ability to detect additional risk factors, such as the impact of cataract surgery.
Another factor that might have resulted in differences between these results and those from the earlier population-based studies is the period in which the cataract surgery was conducted. Techniques in cataract surgery and types of lens implants have changed over time. AREDS participants, with their more recent surgery, were probably more likely to have had ultraviolet B-blocking lens implants inserted than persons who had lenses implanted earlier. Some have hypothesized that insertion of such lenses may decrease the risk of AMD by blocking ultraviolet B exposure of the macula. Thus, the greater likelihood of extracapsular cataract extractions with insertion
of ultraviolet-blocking lenses in AREDS participants may explain some of the differences in findings.
In the AREDS population it seems that cataract surgery was not associated with a clinically important increase in the rates of development of advanced AMD. Persons with intermediate AMD (bilateral large drusen) or with unilateral advanced AMD should be aware of the fact that the risk of developing advanced AMD is as high as 50% in 5 years, regardless of cataract surgery. Although the results of AREDS analyses suggest that this risk does not seem to be accelerated by cataract surgery, the patient still should be counseled as to the risk of development of advanced AMD because of the natural course of the disease.
In summary, the AREDS data suggest that there is no clinically important increased risk of progression to advanced AMD after cataract surgery. This is the only prospective study in which the severity of AMD was documented before and after cataract surgery in a large number of cases with more than 5 years of regular follow-up. These data, which are contrary to that of previously reported results, may provide some reassurance to patients with AMD who are considering cataract surgery.
WHAT IT MEANS TO YOU: Concerns surrounding the role of sunlight in the development of AMD has lead to increase speculation that cataract surgery, with its resultant increase in macular sunlight exposure, may increase the risk of AMD. Earlier research, which suggested an increased risk of AMD progression following cataract extraction, has helped to fuel this speculation. But AREDS has clearly demonstrated that cataract surgery as it is being performed today does not increase the risk of AMD progression. This begs the question whether there is a need for blue-blocker intraocular lenses to protect the macula. If cataract surgery with UV-blocking does not place the macula at-risk for AMD progression, then blue-blocker IOLs may not provide any clinically important additional benefit.
Read more...
Ophthalmology. 2009 Feb;116(2):297-303. Epub 2008 Dec 16.
