Cataract Surgery and Astigmatism
Normally when we think about corrective eye surgeries, we think about things like Lasik, which corrects myopia. As a person with both myopia and astigmatism, I didn’t know that there were options for managing astigmatism through surgery as well. However, thanks to modern advances, there are now techniques for managing astigmatism during cataract surgery! There are three phases that need to occur during these vision correction surgeries; evaluation, marking and finally, the surgery itself.
During the evaluation stage, the degree of astigmatism is measured in order to achieve the best surgical plan for this patient. Various scans and advanced technologies, such as Optical Low-Coherence Reflectometry, are used to scan and measure the degree of astigmatism in each eye. Corneal topography technology, which evaluates the surface of the cornea is also used. Next, the eyes must be marked in order for the surgeon to know where to cut. For this, tools such as the SMI Surgery Guidance Technology are used.
There are currently two main options for astigmatism-correcting surgery techniques; PCRIs and toric IOLs, which are sometimes combined. PCRI, which stands for Peripheral Corneal Relaxing Incision, is a larger incision that is used to correct astigmatism. The other option, toric IOL, is a newer development. It is an IntraOcular Lens that is placed into the eye to correct astigmatism. These two options are relatively equal in effectiveness, with toric IOLs performing a bit better for higher astigmatism levels ( greater than 2.00).
Although these methods are extremely effective, true spectacle independence (vision without glasses) is not achieved; astigmatism levels are only lowered. Additionally, for every degree off axis that the toric IOL lens shifts, there is a 3.3% loss in vision correction. Hopefully, the field of ophthalmology will develop new cataract surgery techniques to cure people of astigmatism for good soon in the future.