Over 95% of patients will not require spectacles or lenses for most everyday activities after treatment for mild to moderate myopia (up to -5.0 dioptres), while the remaining few patients may require them for visually demanding tasks such as driving.
For higher levels of myopia (greater than -5.0), it’s less likely that patients will be able to see perfectly unaided. However, your unaided vision will be significantly improved and you’ll need much thinner glasses. Above -5.0 dioptres, over 90% of patients can expect 6/12 or better unaided vision.
It should be explained that 6/12 is approximately the visual acuity required to drive a car, play most sports and perform many day-to-day tasks. 6/6 vision is “perfect” or “normal” vision (which is probably the vision that you currently have with spectacles).
The degree of myopia can change a little for up to six months after your laser treatment, but after this the effects usually stabilise. While it’s established that laser eye surgery can reduce the degree of your short-sightedness, the exact amount it will affect your vision can’t be guaranteed.
The results of excimer laser treatments performed at Sunderland Eye Infirmary are continuously audited.
The response of astigmatism to excimer laser is more variable than myopia alone. This means that if you only have myopia or a low level of astigmatism, your outcome is likely to be better than the results we’ve detailed above.
Over 95% of patients with low degrees of hypermetropia (up to +3.0 dioptres) can expect to achieve 6/12 or better unaided vision following treatment.
Higher degrees of hypermetropia (over +3.0 to +6.0 dioptres) are more difficult to correct, but patients can expect an 85% chance of 6/12 or better unaided vision after treatment.
For people with extreme long-sight of over +6.0 dioptres, results are much less predictable and outcomes would need to be discussed at the assessment consultation.
The outcome of treatment for astigmatism will depend on the degree of the astigmatism and the kind of treatment you opt for.
On average, patients can expect to experience a reduction of 66-75% in the amount of astigmatism. However, this can vary from patient to patient.
If the residual astigmatism after treatment is less than 1.0 dioptre and there is no significant short- or long-sight, then your unaided vision should be good enough for you not to have to wear glasses or contacts.
Higher degrees of residual astigmatism might mean that you’ll still need glasses or contact lenses are required to achieve the best vision.
All forms of surgery carry some degree of risk and complications are possible
However, refractive surgery has a high safety record. It is however an elective procedure and there are certain potential complications and risks that you should be aware of before you consider treatment.
The surgeon is able to fairly accurately predict your expected result, but as each person has a different prescription and healing rate it is not possible to give an absolute guarantee.
Short-term side effects
(which should not permanently affect vision)
Glare/light sensitivity: After treatment you’ll likely be sensitive to sunlight and glare. This usually settles within a few days.
Fluctuations in vision: Fluctuations in vision are a normal part of the healing process. These usually last for less than a month.
Difference in refractive error between eyes: If only one eye is treated at a time this means that for a period of time (depending on the timing of the treatment of the second eye), the untreated eye will be short- (or long-) sighted and the treated eye may be normally sighted. If you have a high prescription you may not be able to wear glasses that correct the vision in both eyes during this time.
Dry eyes: A few patients may experience some discomfort due to dry eyes after laser surgery. This may require the use of lubricating treatment. Symptoms will normally resolve within six months.
(which should not affect best corrected vision)
Overcorrection or undercorrection: As all patients’ eyes differ in the rate and method of healing, treatment might not result in the expected correction. Over 95% of patients with lower levels of myopia achieve 6/12 without glasses. However, some will be a little over or under corrected and will still require glasses or contact lenses. There can be no guarantee of the final results of the treatment. In general, all patients obtain a significant improvement with unaided vision, and if glasses are still required these are usually much thinner than before.
Reading glasses: A person with normal vision when younger will require reading glasses from the age of about 45 years. If myopia is corrected, the patient will effectively become “normal sighted” – though glasses may not be required for everyday tasks, when the person reaches middle age, reading glasses may be required for near work.
Decrease in Best-Corrected Visual Acuity: It’s possible that surgery might affect your best corrected vision (the level of vision you can currently achieve with your glasses or contact lenses). If so, your best vision with glasses may not be as good after surgery as it was before.
Starburst/Night Haloes: Following treatment individuals may experience halos, starbursts or similar effects around street lights and car lights at night. This tends to improve with time, but may not disappear completely. It can make driving at night difficult for some people.
You will have the opportunity to discuss any of these risks in more detail at your consultation.