Lasik surgeons typically define candidates into three different categories:
• Ideal
• Less than ideal
• Non-candidate
There are several health issues that can decrease a patient’s status when determining whether or not they are a good candidate for Lasik.
Extremely Low Vision
Lasik surgery is limited in the amount of vision that it can correct. Some people are beyond the procedure’s ability to help. The FDA does not allow patients with more than +6.00 diopters of hyperopia or –14.00 diopters of myopia to undertake the surgery. In addition, patients with more than 6.00 of diopters of astigmatism cannot have the surgery as well. A doctor is able to determine this information through your refractive eye exam.
Our Eyes Grow Too
As people grow, their eyes continue to change shape and size. A young person’s prescription may change constantly until they are 18 years old. Most prescriptions will stabilize at this time. Surgeons prefer to wait on surgery if the prescription has not stabilized. They like to see a patient with at least two years of a stable prescription. This helps to ensure them that the eyes are not going to change, as this would result in a change of vision should they perform the surgery too early.
Health Factors
There are various other health factors that may prevent you from being an ideal candidate as well. If you have an autoimmune disease that causes you to heal slowly, this opens the door to more complications. If you require medications such as immunosuppressants or steroids, then you are also less than ideal as these medications cause you to heal slowly. Also, patients who are pregnant are not ideal because the shape of the eyes can change temporarily due to a hormonal influence.
Anterior Eye Health
Doctors divide the eye into two portions, the anterior and the posterior. The anterior is the front portion of the eye that includes the cornea, eyelids, iris, conjunctiva, sclera and lens. The surgeon will check for abnormalities in these parts of the eye with a biomicroscope, or slit-lamp. The doctor shines a line into the patient’s eyes to examine the anterior of the eye. Abnormalities in these areas can decrease a patient’s likelihood of being an ideal surgery patient.
Posterior Eye Health
The posterior portion of the eye is the back of they eye. There are several diseases that can be detected through a posterior eye exam including:
• Glaucoma
• Ocular hypertension
• Diabetic retinopathy
This area includes the optic nerve, retina and blood vessels.
Irregular Shaped Cornea
A cornea that is irregular can be impossible to operate on. If patients have the condition keratoconus, they are ineligible for the procedure. This is because the cornea is a cone shape. A small amount of irregularity is okay, but a corneal topography will be required to determine the shape and severity of cornea shape.
Thin Corneas
Some patients have corneas that are thin, making it impossible to create the corneal flap in the surgery. If these patients were to have surgery, their vision would actually become worse instead of better. The doctor measure the thickness of the patient’s cornea using a device called a pachometer. Lasik surgery is an extraordinary procedure that has helped thousands of people see better.