Thursday, March 2, 2017

Cataract surgery in people with age-related macular degeneration

Cochrane: The aim of this Cochrane Review was to determine whether cataract surgery is safe and improves vision in eyes with age-related macular degeneration (AMD) compared with no surgery. Cochrane researchers collected and analyzed all relevant studies to answer this question and included two studies. Although data from two small studies suggest that surgery to remove cataracts in eyes with AMD may improve vision without worsening of AMD, it is not possible to draw reliable conclusions from the available data at this time. Physicians must decide whether to recommend cataract surgery to their AMD patients based on clinical judgment until larger studies have been conducted and their findings published.

What was studied in this review?
Both cataract and AMD are common causes of poor vision; they often occur together in people over age 50. Cataract occurs when the clear lens in the front of the eye becomes cloudy. Removing the cloudy lens (cataract surgery) restores good vision for many eyes that do not have other eye conditions. AMD is disease in which the macula (the area in the back of the eye that is responsible for central vision) deteriorates. Some physicians believe that cataract surgery may put eyes that have AMD at higher risk of more vision loss than leaving the cloudy lens in the eye.
What are the main results of this review?
This review included two studies comparing immediate cataract surgery (within two weeks) with delayed cataract surgery (at six months) for people who had both cataract and AMD. In one study, the group that received immediate surgery had better vision at six months than the group scheduled for delayed surgery. In the other study, it was unclear which group had better vision improvements at 12 months. No participant in one study had the AMD get worse; AMD got worse in only one person in the immediate-surgery group in the other study. Two studies measured quality of life: one study suggested that the immediate-surgery group had a better quality of life than the delayed-surgery group, and the second study did not report enough information to allow us to analyze the data. Neither study reported adverse events.
How up-to-date is the review?
Cochrane researchers searched for studies that had been published up to 2 December 2016.
Authors' conclusions: 
At this time, it is not possible to draw reliable conclusions from the available data as to whether cataract surgery is beneficial or harmful in people with AMD after 12 months. Although cataract surgery provides short-term (six months) improvement in BCVA in eyes with AMD compared with no surgery, it is unclear whether the timing of surgery has an effect on long-term outcomes. Physicians must make recommendations to their AMD patients regarding cataract surgery based on experience and clinical judgment until large controlled trials are conducted and their findings published.
There is a need for prospective RCTs in which cataract surgery is compared with no surgery in people with AMD to better evaluate whether cataract surgery is beneficial or harmful in all or a subset of AMD patients. However, ethical considerations preclude withholding surgery, or delaying it for several years, if it may be a potentially beneficial treatment. Designers of future trials are encouraged to utilize existing standardized systems for grading cataract and AMD and for measuring key outcomes: visual acuity, change in visual acuity, worsening of AMD, quality of life measures, and adverse events.