Your pre-operative LASIK eye exam.
As part of preparation for LASIK, you will receive a dilated pre-operative eye exam. At Cutarelli Vision, we believe this can be one of the most important steps of your procedure.
If you are having your LASIK candidacy screening performed through your own eye care professional, you are still required to complete a pre-operative LASIK exam at our office before your LASIK procedure. We will be unable to confirm your candidacy for LASIK or LASIK alternatives until these tests are completed.
Someone to drive you home
For your eye exam, we will need to dilate you to look inside your eyes. We recommend that you bring a dark pair of sunglasses or we’ll be happy to supply you with disposable sunglasses during your appointment. Although rare, some patients may not like being dilated, or might have extreme light sensitivity. In this case, we recommend you bring someone with you to drive.
Assessment of your eye health history
Current prescription: Your current prescription needs to be stable during the last 2 years in order for LASIK to be appropriate at this time.
Contact lens wear: Contact lenses warp the corneal surface and cause measurements that are not representative of your true refraction. You will have to stop wearing contact lenses prior to LASIK eye surgery. The time interval required depends upon the type of lens and how long you have been wearing them, and may be longer than the minimum times listed below depending on your initial topography results.
- Soft lenses
- At least 1 week prior to your dilated LASIK exam
- At least 1 week prior to LASIK surgery
- Gas permeable and true hard (PMMA) lenses
- At least 3 weeks prior to your dilated LASIK exam – if you have worn them for more than 10 years an additional week for each decade of wear will be required. Remember, the accuracy of your measures depend on patient diligence. Please follow this advice in order to avoid unnecessary risk of complications or poor visual outcomes.
Ocular or systemic diseases and medications: Some ocular or systemic diseases and medications can affect your suitability as a candidate for LASIK.
Previous ocular problems: This refers to such conditions as lazy eyes , strabismus , or double vision and will need to be addressed in order to validate your candidacy for LASIK.
Previous eye injuries: Be sure to inform Dr. Cutarelli about any eye related injury, regardless of how long ago it occurred.
Your pre-operative eye exam:
Refraction: This test determines the visual acuity of your eyes, both uncorrected and as corrected by glasses or contacts, both with and without dilation.
Motility: This exam will assess the ability of the muscles to align your eyes properly.
Eyelids: This test exams your eyelids to see if they turn inward (possibly scratching the cornea ) or outward (possibly directing tear flow away from the eye), plus other related conditions that might effect your vision.
Conjunctiva: The conjunctiva is the transparent membrane that covers the outer surface of the eye and lines the inner surface of the eyelids. This test will check for irritations, redness, irregular blood vessels or other abnormalities.
Cornea: The cornea will be examined for overall health, scarring, any previous trauma, and pathology, using slit lamp device that acts as a microscope for doctor.
Crystalline lens: This natural lens inside your eyes will be examined to determine if clouding of the lens (a cataract ) or other abnormalities are currently present.
Intraocular pressure: The intraocular pressure inside your eye will be measured to detect glaucoma or pre- glaucomatous conditions. Glaucoma is a visual loss caused by damage to the optic nerve from excessively high pressures in the eye. It is one of the most common causes of preventable vision loss.
Posterior segment: The dilated (fully open) pupil exam is used to assess the health of the posterior segment (inside back surface of your eye). This test allows Dr. Cutarelli to screen the retina, optic nerve, and blood vessels for a number of eye and systemic disorders.
Tear film: It is very normal for patients to experience temporary dryness after LASIK. However, patients who have inadequate tears before surgery are at higher risk of prolonged dry-eye symptoms after surgery. Keep in mind that feeling of dryness while wearing contact lenses is not the same thing. Experiencing dry eyes while wearing contact lenses does not mean that the eyes are dry when contact lenses are not being worn.
- Different methods to evaluate tear function include:
- Placement of colored agents in the tears
- Physically measuring the tears themselves
- Inspection of the tear film with a microscope
Pupil size: Most glare, halos, and diminished night-vision following LASIK surgery is due to a combination of larger pupil size and a high amount of nearsightedness or farsightedness. Because large pupils allow light rays to enter from the periphery of the cornea, custom programming the laser for a larger optical and ablation zone can minimize glare and halos. However, this can only be accomplished with lasers that have an adjustable zone from 6.0 mm to 8.0 mm, such as the ones we use here at Cutarelli Vision.
Pupils should be measured when they are the largest potential size, which occurs under the darkest conditions.
- There are four methods for pupil size evaluation:
- Light amplification – utilizing night vision technology derived from the military, an examiner looks through one end of the device at the pupil. Pupil diameter is measured against a tiny ruler in the viewfinder to give accurate measurements in room light that would otherwise be too dark to take a measurement.
- Ruler card – a technician uses a hand-held card with different sized circles on it to match the diameter o the pupil to that of a circle on the card. This has the disadvantage of requiring that the room lights be bright enough for the examiner to read the card; therefore, the pupils may be smaller with this level of illumination than they would really be with nighttime illumination.
- Visual estimation – a technician guesses the pupil size by simply looking at it. This is the least accurate method and has the same disadvantage of the ruler card of requiring bright enough lighting for the examiner to see the pupils.
- Epithelium: The cornea is covered on the surface with a thin clear layer of skin cells, called the epithelium. In some people, this layer of cells is not attached firmly. Loose epithelium may lead to a higher risk of complications. By microscopic examination of the cornea, this test will determine if a loose epithelium condition exists.
Corneal thickness: The medical term for measuring corneal thickness is pachymetry. This test will be used to calculate precisely how deep the laser will be allowed to penetrate. Since LASIK involves creating a flap on the surface of the cornea and using a laser to reshape the cornea by removing tissue, it is possible for the laser to remove too much, leading to corneal bulging and distorted vision. In order to be sure the laser does not penetrate beyond the safest level, pachymetry is imperative.
Topography: Using a topographer, your eyes will be tested by corneal topography. As no one has a perfectly rounded cornea, the topographer machine will display the degree of astigmatism you have – the irregularities and actual steep or flat shape of your cornea, which cause your vision to be less than perfect. Occasionally patients have abnormal astigmatism called keratoconus, which is a cone-shaped cornea. These corneas often are weaker than normal corneas and thus should not be treated by LASIK.
Wavefront Mapping: The VISX CustomVue Wavefront Analyzer will provide a detailed analysis of your entire visual system. Dr. Cutarelli will use this information to further validate that you are an appropriate laser eye surgery candidate and formulate a highly customized vision correction plan specifically for your eyes. Read our section on Wavefront LASIK for more information on this incredible technology.
Vocational and lifestyle: Your work or recreational requirements can influence vision correction choices. For example, some choices can affect depth perception or the ability to see well at a particular distance.
Reviewing the results: You and Dr. Cutarelli will go over the results of your exam together and further plan your LASIK eye surgery.
Next step: Schedule and prepare for your LASIK procedure. This appointment will be scheduled at the time of your comprehensive eye exam.