Perhaps the most common and well-known of all eye afflictions is the clouding of the lens of the eye, called cataracts. One can trace surgery to remove the clouded lens of the eyes back to the Babylonians. Over the past few years, there have been huge advances in cataract surgery. Long hospital stays and the use of glasses with thick lenses are a thing of the past. Today the cataract operation is a quick procedure and the recovery period is only a few days with very little pain and discomfort. With advanced I surgical techniques and the use of intraocular lenses, cataract surgery is one of the great success stories of the modern medical profession.
There are four types of cataracts: cortical, nuclear, sub-capsular and traumatic.
The most common symptoms are:
Cataracts are removed by a surgical procedure whereby the clouded lens is removed and replaced with an artificial one.
The lens is replaced by a manufactured intraocular lens (IOL) which becomes a permanent part of the eye. If you are not suitable to receive an IOL you might be given a soft contact lens or spectacles. You will need reading spectacles after the operation.
LASIK is the acronym for “laser in situ keratomileusis”, sometimes referred to as “laser assisted in situ keratomileusis”. This procedure stretches as far back as 1949 when it was first performed as a lathing procedure. Since the 80's it has steadily seen improvements to the point where today it can be regarded as a safe option in refractive surgery.
Lasik is commonly performed mainly because of a relative lack of pain immediately after the procedure and because good vision is achieved within a day, if not immediately.
Persons with myopia, hyperopia and astigmatism can benefit from LASIK but you must have realistic expectations and be aware of the risks involved. The surgeon will make a thorough assessment to establish if you are a suitable candidate.
There are many questions your surgeon will be asking in an effort to establish if you are an ideal candidate. Trust your surgeon to give you the best advice.
Over 90% of patients with low to moderate myopia will achieve 20/40 vision. More than 50% of patients can expect 20/20 vision or better. However patients with high myopia (more than -7D) and high hyperopia (more than +4D) should not have the same expectations.
This operation is characterised by speedy visual recovery. Most will have good vision within a day after surgery though vision will continue to improve. You might have to wait 2 to 3 months to achieve optimum vision. Some patients experience glare or halos around objects in low light conditions, but it is of temporary nature in most cases.
The operation will take approximately 30 - 45 minutes and you can expect to stay in hospital for 2 - 3 hours. The operation itself is painless because patients are given a topical anaesthetic. A speculum is used to keep the eyelids open. A vacuum ring is placed onto the eye after which the surgeon cuts a very thin corneal flap. The cutting is performed on the cornea on the outside of the eye and is painless.
By using a computer the surgeon adjusts the laser for your particular prescription. The laser then reshapes the central area of the cornea. During this time you are asked to look at a target light to ensure your eye remains in the correct position. The corneal flap is then put back into place. The corneal flap then attaches itself to the rest of the cornea with barely a scar visible. No stitches are used in this procedure.
An eye shield must be worn for a couple of nights and eye drops used for 3 days.
Talk to your surgeon about post-operative activities that perhaps should be curtailed for a period of time, such as contact sports.
The central area of the eye is filled with a jelly-like substance called the vitreous which is firmly attached to the macula. With age the vitreous gel begins to shrink and is replaced by a liquid. As it shrinks it also becomes thinner and separates from the retina. This sometimes causes traction or pulling on the central retina which results in a small hole being formed - called a macular hole. Central vision is gradually affected depending on the extent and severity of the problem.
Symptoms may vary depending on whether the hole is of partial or full-thickness.
Sometimes macular holes heal spontaneously with no need for treatment. If not, surgery is required in order to close the hole and restore useful vision.
The procedure is called a vitrectomy during which the surgeon first removes the vitreous gel. This is done to eliminate any traction on the macula and allows it to settle against the wall of the eye. A substance is then injected into the macula to close the hole.
For healing to run its full course, a gas bubble is injected into the eye which presses the retina against the wall of the eye and in so doing help to seal the hole. After the bubble has dissipated and the eye has healed functional vision is usually restored.
The patient is required to stay in a FACE-DOWN position to ensure that the gas bubble presses the macular hole firmly against the back wall of the eye. Approximately 6-8 weeks after surgery the patient is measured for spectacles. To achieve full visual recovery usually takes up to 3 months. The extent of visual recovery depends on the size of the hole and length of time present.
Acute angle-closure glaucoma, also simply called acute glaucoma, is a disease in which there are sudden increases in the pressure in the eye – intraocular pressure – usually on one side only, with severe pain and loss of vision. Repeated attacks may occur and may progressively reduce the visual field.
There is also a chronic form of this disease, called chronic angle-closure glaucoma, in which the intraocular pressure remains or is raised repeatedly, but with less severe symptoms. In this case the obstruction to drainage of the liquid in the eye (aqueous humor) is gradual.
This type of glaucoma is caused by acute obstruction of the drainage of the liquid in the eye – the aqueous humor. This is usually due to an anatomic abnormality of the eye in which the front part (anterior chamber) is shallow. This occurs most commonly in an older person who is long-sighted.
An acute attack is precipitated by partial dilatation of the pupil, which blocks the drainage of fluid out of the eye. The pressure inside the eye (intraocular pressure) rises quickly and may be very high.
The pupil dilatation may be caused by poor light, fear, anxiety or medicines, such as certain anti-epileptic drugs.
Women are more likely to get acute glaucoma than men. It is unusual over the age of 45. Those most at risk are elderly people who are long-sighted.
The eye is engorged and red – visibly swollen. The surface of the cornea is dull. The pupil does not respond to differences in light – fixed and non-reactive – is semi-dilated and often slightly oval in shape.
The appearance of the eye can allow the doctor to make a diagnosis.
The intraocular pressure is raised, often to around 60 mm Hg.
This disease can be prevented if an eye at risk has a minor laser procedure called a laser iridotomy.
The initial treatment is to lower the intraocular pressure and to constrict the pupil.
Acetazolamide tablet (and sometimes other medication such as Mannitol-intravenously or Glycerol- per mouth) is given to reduce the rate of formation of aqueous humour. Pilocarpine drops are used to constrict the pupil. Topical B-blockers to prevent aqeous production and steroids to decongest the eye.
Nausea is controlled using anti-emetics if necessary.
Painkillers can be used as necessary.
The definitive treatment is surgical. A peripheral iridotomy using a laser (or occasionally surgery) is done. A pinpoint sized hole in the iris is made to allow free flow of fluid between the anterior and posterior chambers of the eye. This is often carried out on the other eye as well, to prevent the problem recurring.
If the pressure doesn’t control filtration surgery is done.
If you develop a very painful, red and swollen eye and your vision is decreased, you should see your doctor immediately.
Reviewed by Dr L.Venter, MB Ch B, MMed (Ophth) + FC Ophth SA , (December 2010)
Iritis is the inflammation of the iris (the ring of coloured tissue surrounding the pupil of the eye).
Iritis is the most common form of a family of conditions called uveitis. The uvea extends from the front to the back of the eye and comprises the iris, the ciliary body which is behind the iris(this structure focuses the lens) and the choroid body which is at the back of the eye surfaces (layer rich in blood vessels that lines the back of the eye and supplies blood to the retina).
Anterior uveitis predominantly involves the iris, but the ciliary body can be involved as well. In this case it is called iridocyclitis.
Certain medical conditions such as Ankylosing spondylitis, Ulcerative colitis, Crohn's disease and Sarcoidosis are associated with iritis.
It can also result from an infection in another part of the body (such as shingles, chickenpox or the cold sore virus) that spreads to the eye.
Injury to the eye and eye surgery may also bring on an attack of iritis.
In many cases, the cause of iritis is unknown.
Symptoms of iritis include:
Generally, the eye is not sticky or crusty. These symptoms are more suggestive of conjunctivitis.
An ophthalmologist will use an instrument called a slit lamp to examine the inside of the eye and can usually make the diagnosis on the basis of this examination.
Since iritis may be associated with disease elsewhere in the body, the ophthalmologist will require a thorough understanding of your overall health. This may involve consultation with other medical specialists.
The ophthalmologist may also request blood tests, X-rays and other specialised tests to establish the cause of iritis.
Eye drops (especially steroids such as prednisolone or dexamethasone) and pupil dilators are medications used to reduce inflammation and pain in the front of the eye.
The steroid drops may need to be instilled frequently (in severe cases, as often as every half hour). Your ophthalmologist will arrange to see you again to assess the progress of the treatment and will, according to the degree of inflammation, decrease or increase the treatment at this stage. If the iritis is severe or non-responsive, a sub- conjunctival steroid injection is used.
Pupil-dilating drops (such as cyclopentolate or atropine) make you feel more comfortable and prevent certain complications of iritis. This prevents the iris sticking to the lens called posterior synegie. However, you may become more sensitive to bright light, lose the ability to focus on near objects and your vision may become more blurred.
Uveitis arising in the front or the middle of the eye (iritis or iridocyclitis) is usually more sudden in onset and generally lasts six to eight weeks. In early stages, it can usually be controlled by the frequent use of drops.
Uveitis in the back part of the eye (choroiditis) is usually slower in onset, may last longer and is often more difficult to treat. When uveitis is due to an infection in another part of your body, it tends to clear up once the underlying infection is treated.
In most cases, complications are rare but they include: glaucoma (high pressure in the eye causing damage), cataracts (clouding of the lens of the eye) and neovascularisation (new blood vessel formation).
If left untreated, inflammation in the eye can lead to permanent damage and even vision loss.
If you have been experiencing severe eye pain, blurred vision, sensitivity to light and watering of the eye, or if you notice that one pupil is smaller than the other, you should call your doctor.
Reviewed by Dr L.Venter, MB Ch B, MMed (Ophth) + FC Ophth SA , (December 2010)
What is the retina? Imagine your eye is a camera and the retina is the film. The retina is the lining of the back wall of the eye. Light rays enter the eye and are focussed onto the retina by the lens. The retina in turn is where the image is formed which is then carried to the brain by the optic nerve. The macula is the area of the retina where central vision is the clearest. Just as you need a good film to make good pictures you need a healthy retina for good vision.
Usually the retina is attached to the wall of the eye but a tear or hole in the retina can result in fluid getting underneath it. This separates the retina from the back of the eye and causes it to detach which can result in devastating damage to the vision if left untreated.
Middle-aged and older people are more susceptible than younger people. Those who are near- sighted (myopia), who have undergone eye surgery, who are diabetics and who has suffered a serious eye injury, are also more susceptible to retinal detachments. In some cases it can also be hereditary.
A shadow/curtain/veil spreading across the vision of one eye (most common)
The treatment depends on the severity, type and location of the detachment. Early detection will perhaps only require laser or freezing treatment. Usually an operation to repair the detachment is needed. In most cases a single operation will rectify the problem. Sometimes fluid must be drained from under the retina to allow the retina to settle back onto the back wall of the eye. In other instances the surgeon removes the vitreous from the eye and a small gas bubble is injected into the vitreous cavity. This bubble then pushes the retina against the wall of the eye. In some cases a pressure pad/sponge or a silicone band is placed on the eye to close the hole causing reattachment.
If there is little or no retinal detachment, the tears are sealed by means of a laser. This "tacks" down the retina by placing small burns around the edges of the tear.