What is Surgery for High Myopia?
Surgery for high myopia refers to surgeries employed in the treatment of high myopia. Some of these surgeries include photorefractive keratectomy (PRK), LASIK (laser in-situ keratomileusis), Refractive Lens Exchange (RLE), and phakic intraocular lenses (pIOLs).
Myopia, also referred to as nearsightedness, is an eye condition defined by a refractive defect or error in visual focusing. When you are nearsighted, nearby objects can be seen clearly, but objects in the distance appear blurry. High myopia occurs when a patient’s myopia requires -5 diopters or more of correction. A diopter is a unit that measures the focusing power of a prescription lens. A negative diopter reading indicates nearsightedness, and the higher the negative number, the thicker your lenses will be. High myopia increases the risk of blinding eye conditions, such as macular degeneration, retinal detachment, glaucoma, and cataract.
Preparation for High Myopia Surgery
Prior to your high myopia surgery, your doctor will review your medical history and perform a thorough eye examination to:
- Test your vision
- Measure your pupil size
- Measure and map the surface of the cornea
- Measure the refractive error in each eye
- Check for other eye problems
Your doctor may also ask you to follow other preoperative instructions, such as:
- Eat a light meal before coming for the procedure
- Prescribe antibiotic drops and anti-inflammatory drops for a few days before surgery to prevent infection and inflammation
- Take all your usual prescribed medications
- Do not apply any eye makeup
- Do not wear any bulky hair accessories
- Wear comfortable clothing
Surgeries for High Myopia
Common surgeries performed to correct high myopia include:
Photorefractive keratectomy (PRK): PRK is a laser surgery performed to correct vision problems caused by refractive errors. Refractive errors occur when the eyes do not refract or bend light to properly focus on the retina, resulting in blurred vision. PRK works by reshaping the cornea using a laser so that light entering the eye is correctly focused on the retina to deliver clear vision without the need for contact lenses or glasses.
Procedure: PRK is a painless procedure that is performed under local anaesthesia in an outpatient setting and usually takes about 15 minutes. It involves the following steps:
- Your surgeon will first numb your eye with anaesthetic eye drops.
- An eyelid holder will be placed on your eye to prevent the eye from blinking.
- You will be asked to focus on a target light so that the eye remains still.
- The outer layer of epithelial cells from the cornea is removed using a blade, special brush, alcohol solution, or laser.
- Computer-controlled pulses of light energy or laser are used to reshape the cornea.
- A contact lens is placed on the eye as a bandage for 4 to 6 days while the epithelium of the cornea heals.
- A medical professional will remove the “bandage” contact lens once the epithelium heals in 4 to 6 days.
LASIK: LASIK is a widely used refractive eye surgery to correct nearsightedness, farsightedness, presbyopia (loss of ability to focus on nearby objects), and astigmatism (improper curvature of the eye’s surface). The surgery works by remoulding the cornea (transparent dome-shaped front part of the eye), allowing proper focusing of the light that passes through the cornea onto the retina (light-sensitive membrane at the back of the eye).
Procedure: You will be seated in a reclining chair and given medication to relax you. Eye drops will be instilled to numb your eyes. Your doctor will use a special instrument to keep your eyes open during the procedure. You will be asked to focus on a source of light in order to keep your eye fixed during the procedure. Your doctor will then use a special cutting laser to cut a thin flap in the cornea similar to a hinge. The flap will then be peeled back and the underlying corneal tissue will be remoulded. Once the cornea is reshaped appropriately so that it properly focuses light onto the retina, your surgery will be completed by folding the cornea flap back into place, where it will heal normally without the need for stitches. The entire procedure takes around 30 minutes or less.
Phakic Intraocular Lenses (pIOLs): Phakic intraocular lenses, also called phakic lenses, are artificial implants made of silicone or plastic. They are implanted into the eye without removing the eye's natural lens to minimise your need for glasses or contact lenses. Phakic lenses work by correcting the refractive error- that is the error in the eye's focusing power. Phakic lenses cause the light that enters the eye to be focused properly on the retina and thus, provide clear distance vision.
Procedure: For a phakic intraocular lens implant surgery, you are placed in the supine position, on your back with your face towards the ceiling.
- Your eye is cleaned.
- A lid speculum is used to hold your eyelids open.
- You are administered local anaesthesia in the form of eye drops to numb the eye or it could be given as an injection around the eye.
- You may also be administered another medication such as a sedative through the intravenous route to keep you relaxed.
- A tiny incision is made in the front of your eye. It could be in the cornea (the transparent part of your eye), sclera (the white part of your eye), or limbus (where the cornea meets the sclera).
- A lubricant may be applied near or inside the incision to facilitate smooth insertion of the lens and protect the back of the cornea during lens insertion.
- The phakic intraocular lens is inserted through the incision and placed either in front or just behind the iris.
- The incision may be closed with tiny stitches.
- Your doctor may administer medicated eye drops or apply ointment to your eye.
- Your eye is covered with a patch for protection while it heals.
Refractive Lens Exchange (RLE): Refractive lens exchange is used for the correction of severe farsightedness, nearsightedness, presbyopia (diminished ability to focus on near objects), and astigmatism (blurred vision) that is not easily managed by other refractive procedures. In refractive errors such as hyperopia (farsightedness) or myopia (nearsightedness), the light entering the eye does not focus properly on the retina because of the lens which is either too weak or too strong to help focus light properly. The refractive lens exchange procedure corrects the error and focuses the light on the retina by removing the natural lens in the eye and replacing it with a new artificial lens, thus reducing or eliminating the need for additional glasses or contact lenses.
Procedure: The RLE procedure usually takes about 20 minutes and is performed under local anaesthesia. Once the eye is numbed, a tiny incision is made in the periphery of the cornea. Your surgeon uses an ultrasound probe to break up the lens which is then removed by suction. This process is called phacoemulsification. Then the plastic lens is introduced in the same lens capsule as the natural lens. The incision heals on its own and does not require any sutures. Your doctor may administer antibiotic eye drops and place a patch over the eye to protect and facilitate healing.
Postoperative Care and Recovery
Following the surgery, you can expect some irritation as your eyes will be dry. You will be given medicines and eye drops to keep your eyes moist and to prevent pain and infection. Your doctor may advise you to use a patch over your eyes at night until they heal. You may have problems with the vision for the first day after the procedure, but healing occurs fairly rapidly, and you may experience improved vision in a few days. You will need to follow up with your eye doctor in one or two days and keep regular follow-up appointments periodically during the first six months. Most people can return to work in a week. Other instructions may include:
- Arrange for someone to drive you home.
- Keep both eyes closed and rest as much as possible during recovery.
- Limit reading and watching TV for the first few days.
- Do not swim or use a hot tub, spa, or whirlpool for at least 2 weeks to reduce the risk of infection.
- Avoid strenuous activities and contact sports for a few weeks.
- Wear sunglasses while outdoors to prevent discomfort from sun exposure.
Risks and Complications
Surgery for high myopia is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:
- Infection, inflammation, pain, or redness
- Increased intraocular pressure
- Dry eyes
- Delayed surface healing
- Vision abnormalities, such as experiencing glares, halo, or double vision temporarily
- Astigmatism (an imperfection in the curvature of your eye's cornea or lens)