The lens inside our eyes provides the ability for us to focus throughout our youth and into our adulthood. As our eyes begin to mature in our early forties, we begin to lose our ability to focus up close. This is a natural change for our eyes. The crystalline lens is clear in our youth and begins to discolor in the fifth decade of life and can continue to discolor over time clouding our vision. This discoloration of the lens is known as a cataract. If our vision becomes diminished to an unacceptable level and interferes with our daily activities, then there is a need to remove the cataract. Cataract surgery is typically performed when the vision is reduced to about the 20/40 level or worse. Cataract surgery is a routine outpatient procedure these days with the advent of microsurgery techniques introduced in the mid 1980’s.
Diabetes can play a role to speed up the formation of cataracts. If blood sugars are higher than normal (not extreme) excess sugar accumulates in the lens which starts a cascade of biologic events that increases the water content of the lens. With increased water inside the lens, the clear fibers that comprise the lens are stretched and change shape. When blood sugars go down, this hydration process reverses and as the water content of the lens returns to normal and the fibers are relaxed. It is this constant 'push-and-pull' on the internal lens fibers that causes the fibers to prematurely discolor. With larger and more frequent swings in blood sugars this stretching activity continues, thus discoloring the otherwise clear crystalline lens.
These small changes in tissue structure over time discolor the tissue of the lens, hastening the formation of cataracts. This process is accelerated with continuous, large swings in blood sugars.