The eyes are a precious pair of organs, allowing people to see the world around them. It is no wonder that conditions affecting vision can significantly disrupt one's quality of life. This includes cataracts, a common condition affecting the lens in the eye for which surgery is required for treatment.
The following is an overview of cataracts and a look at the different types of artificial lenses.
Cataracts
Cataracts are progressively degenerative opacities within the lens of the eye. They cause painless blurry vision, the extent of which depend on the severity of the opacity and their location in the lens, as well as glare and loss of contrast detection. The condition is typically associated with aging, but other factors are believed to contribute to cataracts, including ultraviolet (UV) rays, x-rays, alcohol, smoking, corticosteroids, diabetes, and trauma.
One can lower the risk for cataracts by minimizing any controllable risk factors. Otherwise, surgery is the treatment for cataracts and are reserved for patients whose vision is severely limited by the condition. Ophthalmologists perform one of two techniques to remove the lens:
- Phacoemulsification: Through a tiny incision, the surgeon melts the hard center of the lens with ultrasound waves, then removes it by suction. Afterwards, he or she removes the soft outer portion of the lens.
- Extracapsular cataract extraction: Through a slightly larger incision, the surgeon removes the hard center of the lens in one piece and extracts the remaining soft outer portion of the lens.
Both procedures leave the lens capsule in place. This way, the ophthalmologist can place an artificial lens in place of the extracted lens. This implant can be in front of the iris (anterior chamber lens) or behind the iris (posterior chamber lens). Following surgery, the patient is given antibiotic and steroid eye drops to minimize infection and inflammation, respectively.
Artificial Intraocular Lens
Different types of artificial intraocular lenses (IOLs) are available for patients who have undergone surgical lens extraction. The following are descriptions of these IOL types, which are either part of standard ophthalmologic practice or considered investigational.
- Traditional IOLs: Traditional IOLs are rigid lenses that provide clear vision at only one distance. Individuals with these types of lenses are required to wear external lenses for clear vision at other distances.
- Multifocal IOLs: To overcome the limitation of traditional IOLs, multifocal IOLs have special designs that handle incoming light in a more sophisticated way, allowing for clear vision at multiple distances. Major brands of multifocal IOLs include ReStor and ReZoom.
- Accommodating IOLs: Accommodating IOLs, including the Crystalens and the Synchrony, are designed to be flexible like a natural lens, changing shape as the distance of an object to the eye changes.
- Other IOLs: Other types of IOLs include flatter aspheric IOLs to boost contrast sensitivity, blue light-filtering IOLs to reduce UV and blue light from artificial light sources, and tonic IOLs for astigmatism.
