Within our eye we have a clear lens that allows light to be focused clearly onto the retina. Whenever this lens becomes cloudy, it becomes what is known as a cataract. This loss of transparency results in blurring of our vision, and may interfere with our ability to work, read, or perform activities that we enjoy.
Cataracts normally progress slowly over time, and cause a slow deterioration in our visual acuity and sharpness. Symptoms associated with cataracts include: blurry vision, declining color and object detail, double vision, glare off sunlight or headlights, difficulty reading, and poor night vision. While cataracts are in the early stages of formation, our vision can often be improved with changes in our glasses prescription. However, once our vision deteriorates to a certain level due to cataracts, your doctor will likely recommend a definitive treatment such as cataract surgery.
As mentioned in the previous description of cataract surgery, intraocular lenses (IOLs) are placed within the eye during cataract surgery to provide correction of our vision. The first IOL was successfully placed in the 1940's in England, and since this time IOLs have continued to evolve into the precise implants that we know today. If no replacement lens was placed within the eye, we would need extremely thick glasses to correct our vision after surgery. Thankfully, due to modern medical technology we have lens implants that correct our vision and decrease our dependence on glasses.
When contemplating cataract surgery, we do have some options with regards to the IOLs. Before we discuss the IOL options further, we need to discuss two separate eye definitions. One is astigmatism and the other is presbyopia. Astigmatism is a term that describes a cornea that is curved in one direction more than the other. This leads to a decrease in the sharpness of your uncorrected vision. Just envision the difference between a basketball and a football. When looking down on a basketball, all directions basically slope away evenly from a central point. When looking down on a football from above, one axis is sloped more than the other. Therefore, people with astigmatism have a cornea that is shaped somewhat like a football. It is estimated that around 20 percent of the population has some degree of astigmatism since birth.