Vision problems
Adapted from the: The American Society of Cataract and Refractive Surgery
The eye is like a camera. In a camera, light passes through a lens system back onto the film. The cornea and lens are at the front of the eye (anterior chamber) and are similar to a camera's lens system. The retina is located at the back of the eye (posterior chamber) and is similar to the camera's film. In the normal eye, light rays of an image pass through the cornea and the lens and are focused directly on the retina to produce a clear image.
Myopia (Nearsightedness)
In a myopic eye, light rays pass through the cornea and lens but the point at which they converge (focus) is in front of the retina, not on the retina. This configuration allows clear images of near objects but not those that are far away. Non- surgical treatment options for myopia include glasses and contact lenses. Surgical treatment options include clear lens extraction, PRK, LASIK, and intraocular lens implantation. While there are numerous surgical options available, not all individuals are good candidates for specific procedures. Patients should review these options in depth with their physicians prior to making any final decisions.
Hyperopia (Farsightedness)
In a hyperopic eye, the light rays do not converge or focus by the time they reach the retina. Hyperopic patients can focus on more distant objects, but not images that are close at hand. Non-surgical treatment options include glasses and contact lenses. Surgical treatment options include clear lens extraction, conductive keratoplasty, PRK, and LASIK. While there are numerous surgical options available, not all individuals are good candidates for specific procedures. Patients should review these options in depth with their physicians prior to making any final decisions.
Astigmatism
With astigmatism, the rays of light do not converge into a single point but form a line on the retina. There are various types of astigmatism included regular, mixed and irregular astigmatism. Currently, excimer lasers in the US are approved for treatment of regular and mixed astigmatism. Recent advances in technology now allow for the therapeutic treatment of induced irregular astigmatism. In the future, this application may be expanded to include all types of irregular astigmatism. Patients who believe they have astigmatism should discuss this subject in further detail with their physician to gain a better understanding of the mechanisms in their case.
Presbyopia
Presbyopia affects people as they enter their 40s. Caused by changes within the eye's crystalline lens as one ages, presbyopia affects everyone, and eventually everyone will need to wear reading glasses or bifocals as one’s near vision decreases. One method of circumventing the problem with near vision tasks with presbyopia is to perform monovision with excimer laser surgery. In monovision, the patient’s dominant eye is treated fully to achieve excellent distance vision. The non-dominant eye, however, is left mildly near-sighted to allow for near vision tasks and delay the need for reading glasses in the future. If you are approaching your 40s and are contemplating laser vision correction, your specialist may discuss with you monovision and presbyopia as part of a proposed treatment plan.