Myopia (short-sightedness), Hyperopia (long-sightedness) and Astigmatism are refractive errors that are conventionally corrected by spectacles or contact lenses. Laser vision correction can permanently correct these refractive errors. This would allow you to discontinue, or to at least significantly reduce your reliance on spectacles or contact lenses.
Refraction is the measurement of the focusing or spectacle power of your eye.
Astigmatism is a common refractive error and vision problem caused by an irregularly shaped cornea. Instead of being spherical, like a football, an astigmatic cornea is oval, like a rugby ball. The astigmatic cornea causes light rays to focus on two points in the back of the eye rather than one as in a normal eye. This results in blurring or distortion of vision. Astigmatism can occur alone or be associated with short or long- sightedness
Yes astigmatism can be corrected together with any associated myopia or hyperopia
To be considered suitable for laser vision correction certain requirements must be met.
You should:
- be 18 years or older
- have had stable vision for at least 1 year (less than +/- 0.5D change in glasses prescription)
- not have any current or previous serious eye diseases
- not be pregnant - your spectacle power may vary during pregnancy
You will undergo a thorough eye examination and some special tests to determine if laser vision correction is suitable for you. Your needs, the options available, and what would be most suitable for you would be fully discussed during consultation.
You will need to stop using soft contact lenses for at least 1 week before you come for your consultation. Gas permeable lenses must be stopped for at least 2 weeks before consultation.
This procedure uses detailed maps and measurements of the curvature of the front surface of your eye to preserve the natural aspheric shape of your cornea. Laser correction re-shapes your cornea and can alter its natural shape creating a particular type of optical aberration called spherical aberration that can cause halos around lights and other night vision problems. Preserving the cornea's natural shape with wavefront optimisation reduces this risk.
Wavefront technology makes the laser vision correction procedure superior to conventional laser treatments.
LASIK involves lifting a thin flap of your cornea created with a femtosecond laser (bladeless) and applying excimer laser to the inner layers (stroma) of the cornea. The excimer laser gently ablates and re-shapes the inner layers of corneal tissue with precision and accuracy, permanently correcting your myopia, hyeropia or astigmatism. The flap is then replaced to cover the treated area. The flap will naturally adhere itself within a few minutes.
LASIK is a short, painless, safe procedure that has become the most popular method used to correct vision.
NO. You will be given anaesthetic drops during LASIK. Also, because only the inner corneal layers are treated, the surface of the cornea remains untouched; and as a result, there is no pain.
YES, because surface ablations require removal of the epithelium (“skin”) of the cornea before the reshaping excimer laser is applied, these procedures can be uncomfortable and sometimes even painful in 1-2 days after treatment. The pain will subside once the epithelium grows back in 3-5 days. You will be given oral painkillers to be taken when needed.
An excimer laser is a machine that uses ultraviolet C light to vaporize and remove tissue to sculpt and reshape your cornea during vision correction procedures such as LASIK and PRK (and other surface ablations). It is a cool laser (does not burn) and has very low penetrance, so it does not cause damage to other eye structures.
A femtosecond is the SI unit of time equal to 10−15 or 1/1,000,000,000,000,000 of a second; or one millionth of one billionth, of a second.
Femtosecond lasers are used to make LASIK flaps and the lenticule in SMILE without the use of a mechanical blade. Flaps are thinner, more predictable in thickness, more uniform and accurate.
You will be given antibiotic, anti-inflammatory and lubricating eyedrops to be used as prescribed. A follow-up examination will be carried out the day after laser and about 3-4 more times thereafter.
Immediately after LASIK, there may be some redness and discomfort in the eyes, and you may find it difficult to keep them open. These symptoms should all settle within 4-6 hours. The most dramatic improvement of vision occurs on the day after laser although it will not be your best achievable vision. This will improve over the next couple of days to weeks. There may be slight fluctuations in clarity of vision but this usually stabilises within 1 month.
After the PRK / EpiLasik procedure, and when the anaesthetic effect of the numbing drops has worn off, there will be tearing, redness, discomfort and sometimes pain in despite of the protective contact lens that is placed in your eyes after laser correction. You may find it difficult to keep them open. These acute symptoms slowly improve over 1-2 days and should all settle within 1 week.
Visual recovery is however much slower than LASIK and SMILE improving over 1-3 months rather than 1-2 days. The “wow” factor of a dramatic improvement of vision the next day does not happen with surface ablations (PRK/EpiLasik/TransPRK). There may also be fluctuations in clarity of vision and the possibility of cornea haze (mild scarring which requires long term eye drops) but this usually stabilises within 1-3 months.
YES. There is a possibility of cornea haze formation with all surface ablations and you will usually need to use anti-inflammatory eye drops for at least 3 months.
Like LASIK, SMILE causes minimal discomfort post-laser and you will feel comfortable within 4-6 hours. However visual recovery is a little slower than LASIK, with some patients requiring 1-2weeks up to 1-3 months for complete clarity
YES. Research has shown that bilateral laser vision correction is both convenient and safe. The advantages include less time needed off work; no difficulty with imbalance of power between the two eyes, faster and easier rehabilitation as both eyes recover together.
There is always the possibility of complications in any type of surgery.
However, in experienced hands and with the latest technologies providing individualised laser vision correction, laser vision correction is now safer, more precise and effective than ever before. All information will be provided at consultation and in a handbook.
POSSIBLE SIDE EFFECTS INCLUDE:
- Dry eyes is a common side effect that many laser vision correction patients experience. This is usually greatest in the 1st few weeks and is easily treated with lubricants. LASIK patients may have more dry eye initially then PRK or SMILE patients.
- Under or over-correction. This can usually be adjusted by further laser treatment (enhancement) at least 3 months later when the vision and refraction have stabilised.
- Night vision disturbance with haloes or starbursts that will disappear or lessen significantly with time. Neuroadaptation also occurs and you may not notice the disturbance with time.
- Night vision disturbance with haloes or starbursts that will disappear or lessen significantly with time. Neuroadaptation also occurs and you may not notice the disturbance with time.
- Cornea haze particularly with PRK (and other surface ablations) which is treated with anti-inflammatory drops over at least 3 months.
- Regression. Sometimes there may be a return of some of your previous spectacle power and a small decline in your vision over time. This regression can be re-treated with an enhancement laser if required
- Cornea ectasia. A rare but serious complication where there is progressive steepening and thinning of the cornea, leading to loss of integrity and warpage that can occur years after laser correction. This can cause permanent loss of best corrected vision
Other rare complications include infection, inflammation within the corneal flap with the possibility of a loss of one to two lines of best-corrected vision.