Suitability test

Suitability test for laser surgery

If you are interested in undergoing a suitability test you should remember that if you wear soft contact lenses then you must remove them at least 3 days (some will require two weeks) before the fitting. If you wear hard contact lenses then you must remove them at least three to four weeks before the suitability test. It is also advisable to bring to the suitability test the most up-to-date glasses you have.

A suitability test should include:

• Checking the prescription of the glasses you have
• Checking the prescription of the glasses that best suit you at present (refraction test) before and after pupil dilation
• A visual acuity test with and without refractive correction (best-fitting glasses)
• Corneal mapping of the topography type (placido disk-based technology) and tomography (Scheimpflug-based technology) that allows demonstrating posterior surfaces and also the corneal thickness at multiple points in the cornea
• A full ophthalmologist examination that includes medical history, ocular history, a slit-lamp examination before and after dilated pupils and a review of the corneal mapping
• A conversation between the doctor and the patient regarding the advantages and disadvantages of each of the existing surgery types (PRK, LASIK, SMILE, lens replacement, etc.)

Checking the prescription of the glasses you have

Checking the prescription of the glasses you have and comparing it against your current prescription is critical in order to verify that the prescription is stable. A change of more than 0.5-1.0 diopter in the past year is a contraindication to performing the surgery. Therefore, it is important to bring your glasses with you.

Corrected and uncorrected visual acuity test

The visual acuity test with and without refractive correction is an integral part in order to check that there is no lazy eye (amblyopia) or an additional pathology/disease, since it is customary not to operate on patients with a lazy eye or an additional pathology in the eye that can impair vision. In addition, this test allows aligning expectations with the patient.

Corneal mapping

Corneal mapping is an integral part of a patient's suitability test. In corneal mapping one looks to see whether there is irregularity in the appearance of the cornea that could be an expression of clinical or subclinical keratoconus, which is an absolute contraindication to surgery. In addition, the thickness of the cornea is checked with the help of the mapping. A thickness below 500 microns and a residual stroma below 300 microns are a contraindication to LASIK surgery, and in these situations the feasibility of PRK surgery only is examined.

Full ocular examination

A full examination begins with talking to the patient (history) and hearing about the health background (is the patient diabetic? are there joint diseases? etc.), the ocular background (has the patient had eye surgery? does the patient suffer from glaucoma? etc.), the family background (were there eye diseases in the family? keratoconus? etc.), work and hobbies (a boxer? a police officer? etc.). Subsequently, a full eye examination with and without dilated pupils is needed. It is important to look for signs of eye diseases in the front and back part of the eye that would be a contraindication to performing laser glasses-removal surgery (severe dryness, eyelid diseases, intraocular inflammation, cataract, glaucoma and retinal diseases).

Summary conversation between the doctor and patient

It is important to emphasize that not everyone is suitable for every procedure. Therefore, the doctor must present to the patient the findings of the suitability test and discuss with him the advantages and disadvantages of each method and the considerations for and against each of them in his specific case. Finally, the doctor and patient need to make a decision together: whether to undergo glasses-removal surgery at all, and if so, which one?