Cataract surgery in patients with pre-existing AMD: Risks and Benefits
Ophthalmologists should not dismiss cataract surgery for patients with pre-existing AMD out of hand because they are afraid of the risks, Dr. Stefan Scholl warned. There are considerable benefits.
Numerous benefits exist, including a possible increase of visual acuity, depending on the stage of the AMD, he said. There are improvements in colour vision, improvement in contrast sensitivity and increase in brightness.
Do not underestimate these benefits in patients already having a reduced VA and visual quality. An increase of only 20/200 can be much more valuable than for someone with a healthy retina, he said.
He acknowledged that cataract surgery in patients with AMD did bear significant risks, including the risk of a progression in the underlying condition. He cited the Blue Mountain/Beaver Dam study, which showed there was a 2.34-fold higher risk of geographic atrophy developing following cataract surgery. For wet AMD, there was a 3.42-fold risk increase.
He showed also that there was oxidative tissue damage as lipofuscin increases with age, leading to an increase in free radicals. Concurrently, melanin decreases. Melanin typically has a free radical scavenging activity. These effects combine to increase the risk of oxidative damage.
He outlined the development of cataract with age, as the 'lens window' turns progressively more yellow after 40 years of age. This creates a blue light filter, to protect the retina, leading ultimately to the development of dense cataract.
This underlined the rationale behind the blue filter IOL. Cataract surgery opens the lens window again, removing the blue filter, he said, and he cited the Beaver Dam study's conclusion that RPE changes and early AMD risk increase with exposure to sunlight.
Using a blue filter IOL offers protection to the retina once more.