From a surgical perspective, the selection criteria used to identify patients for LASIK significantly determines the final outcome of the procedure. A complete pre-LASIK evaluation along with suitable counselling is required to ensure the “right” individual with the “right” information for the “right” procedure. Prior to the evaluation, contact lens wear must be discontinued for a requisite period of time to allow the eyes to readjust and be ready for the procedure. If soft contact lenses are worn, they must be discontinued at least 3 days prior to the evaluation. Should hard or rigid gas permeable lenses be worn, they must be discontinued at least 14 days prior to the evaluation. Five core tests make up the backbone of a comprehensive pre-LASIK evaluation: ultrasound corneal pachymetry, manifest & cycloplegic refraction, slit lamp examination, dilated fundus examination and corneal topography. Pachymetry allows the doctor to determine if the cornea is sufficiently thick to undergo surgery.
At least 250 micrometers of untouched corneal thickness must remain after LASIK surgery. This level is required to guard against a condition known as ectasia whereby the cornea weakens and adversely affects vision. With an ultrasound pachometer, the doctor will use an ultrasonic wand to touch the eye and obtain a reading. The dilated fundus examination provides insight into the overall health of the individual LASIK candidate. The health status will affect post-surgical healing rates. The Wavefront-guided technology came about courtesy of developments in astrophysics. Wavefront analysis can be used in pre-surgical examination to investigate the way light interacts with the optical system of the eye. Wavefront maps can provide a 2-dimensional display of various eye conditions like myopia, hyperopia and astigmatism.
Corneal topography is able to provide a 3-dimensional view of the cornea. The technology arrived from military advances and can be employed by the LASIK doctor to measure and quantify the shape as well as the curvature of the corneal surface. Excessive corneal surface irregularity or a condition known as keratoconus can be detected by corneal topography. These conditions disqualify LASIK and necessitate other types of refractive surgery correction. A pupillometer can be used to measure the diameter of the pupil in the dark. This can be done using infrared light or a simple gauge that allows the LASIK doctor to determine the size of the pupils. Large pupils may predispose to the experience of post-surgery complications like haloes and double images.
The Schirmer test can be used to detect dry eyes. The LASIK doctor may apply a small piece of paper to the eye for a pre-defined period of time. Upon removal, the moisture content of the paper is measured to determine whether the eye is considered too dry such that further exacerbation is likely as a post-surgical complication. Several other tests are available to the LASIK doctor so that a more comprehensive picture of the individual candidate can be developed prior to further consultation. The aim is always to optimise LASIK outcomes in the quest for good vision. A stinging sensation may be felt after the procedure along with some discomfort, mild pain and tearing. The eye or eyes may be sensitive to light and appear bloodshot. Vision is also likely to be blurry but these symptoms are expected to improve dramatically within a few days of surgery. Taking a break for a few days before resuming normal activities is advisable to facilitate healing.
In the event of any severe pain or worsening vision, the doctor should be contacted immediately for follow-up regardless of any scheduled appointment. Consultations with the doctor should be regular for the first 4 to 6 months. The doctor’s advice needs to be strictly followed to optimise healing. Contact lens wear is to be avoided in the operated eye. The likelihood of developing an infection can be minimised by waiting for at least 2 weeks before resuming the use of topical preparations around the eye, the exception being those directed by the doctor. Avoiding activities that could wet the eye is crucial to facilitate infection-free healing.It is important to realise that vision may require up to 6 months of healing after surgery before stabilising.
Certain symptoms will persist through this period and may continue beyond despite improvement. Should further correction or enhancement be desired, eye measurements need to stabilise before any further surgery is considered. Enhancement surgery cannot be concluded on for efficacy because of a lack of rigorous testing. Despite the likelihood of a complication-free surgery, any new or worsening symptoms should be promptly reported to the doctor. This allows appropriate monitoring to be instituted and action to be taken in a timely fashion to prevent vision loss. These measures, when taken collectively, have an important role to play in defining the success of the whole procedure.