Refractive error surgery is used to correct blurred vision, often caused by various forms of refractive error (near-sightedness, farsightedness, and astigmatism) by reshaping the cornea. It allows for improved light focus onto the retina, reducing the effects of a refractive error. It is commonly achieved through laser eye surgery.
What is a Refractive Error?
‘Refractive error’ is a term to cover types of vision problems that reduce the ability to see clearly. It is caused by a misshaped cornea, preventing light from focussing correctly on the retina. It is one of the most common vision problem forms and is commonly missed if they are not severe enough.
There are 4 common types of refractive errors:
- Near-sightedness (myopia) makes far-away objects blurry
- Farsightedness (hyperopia) makes nearby objects blurry
- Astigmatism can make far-away and nearby objects look blurry or distorted
- Presbyopia makes it hard for middle-aged and older adults to see things up close
What Are the Symptoms of Refractive Errors?
- Double vision
- Blurry vision
- Hazy vision
- Seeing a glare or halo around bright lights
- Eye strain (when your eyes feel tired or sore)
- Trouble focusing when reading or looking at a computer
Why Have Refractive Error Surgery and Am I Eligible?
Refractive errors can be caused by:
- Eyeball length (too long or too short)
- Misshapen cornea (the transparent outer layer of the eye)
- Ageing of the lens
The aim of refractive error correction is mainly aimed at people healthy, 18 or over, with no other eye conditions. These candidates commonly are unhappy with the use of glasses or contact lenses and enjoy activities such as swimming, which are otherwise difficult to perform with contact lenses or glasses. Additionally, this surgery is recommended for people whose refractive error cannot be corrected by glasses. However, this surgery is not always recommended for all types of refractive error.
You should not have refractive error surgery if you experience:
- A change in their eyeglass or contact lens prescription in the past year
- Conditions that impair wound healing, such as autoimmune or connective tissue diseases
- Active eye disease such as severe dry eye
- Keratoconus (cone-shaped corneas)
- A recurrent herpes simplex infection involving the cornea
- Taking certain drugs, such as isotretinoin
- Younger than 18 (there are a few exceptions)
Benefits of Refractive Error Surgery
Potentially stops the need to wear glasses or contact lenses or reduces dependence on them for day-to-day activities. In addition, in severe cases that cause such reduced vision that glasses or contact lenses cannot correct, it can significantly improve sight.
Risks of Refractive Error Surgery
- Dry eyes- causes a temporary reduction in tear production
- Glare, halos and double vision – increased sensitivity to light temporarily
- Under corrections- If the laser removes too little tissue from your eye, you won’t get the clearer vision results you were hoping for and may need a further course of treatment
- Overcorrections – The laser may remove too much tissue from your eye
- Astigmatism – caused by uneven tissue removal
- Regression – vision may return to its original state
- Vision loss or changes
Standard Procedures to Correct Refractive Errors
There are two common ways in which to correct refractive errors in patients, which are:
Laser In Situ Keratomileusis (LASIK)
This procedure usually takes around 30 minutes and only requires numbing drops as it is a virtually painless procedure. A small flap is cut away from the front of your eye to allow access to the cornea. Computer-controlled pulses of focused UV light emitted from a laser vaporises tiny amounts of tissue in the cornea underneath the flap to reshape it. The flap is laid back down, and the eye will heal on its own
Photorefractive Keratectomy (PRK)
No flap is created in this procedure and the cells on the cornea’s surface are removed at the start of the procedure. The system works in the same way as LASIK; a contact lens is placed on the eye after surgery acting as a bandage to allow surface cells to regrow.
How Much Does Refractive Error Surgery Cost in the UK?
- This type of eye surgery ranges from £1,195 to £3,750 per eye in the UK.
- It is only available for NHS patients if they have problems focusing that cannot be corrected by glasses or contact lenses. Such problems are usually caused by irregular focus or unequal focus.