Eye Diseases & Conditions

Cataracts

Introduction

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.

Types of cataracts

There are four types of cataracts: cortical, nuclear, sub-capsular and traumatic.

  • Cortical cataracts predominantly occur amongst diabetics. This cataract forms in the lens cortex and gradually extends from the outside to the centre of the lens.
  • Nuclear cataracts develop in the centre of the lens (the nucleus) and are as a result of the ageing process.
  • A sub-capsular cataract begins at the back of the lens. Patients with a high farsightedness (hyperopia), diabetes and those patients taking high doses of steroids, diuretics and major tranquillisers are susceptible to sub-capsular cataracts. However, it must be stressed that more research is needed to distinguish the effect of the disease from the consequences of the drugs themselves.
  • Traumatic cataracts sometimes develop soon after an eye injury, or even years afterwards.

What are the symptoms?

The most common symptoms are:

  • Blurry or cloudy vision (like looking through a cloudy piece of glass);
  • Poor night vision;
  • Sensitivity to light (light from a lamp or headlights seem too bright, causing glare);
  • Colours seem faded;
  • Double or multiple vision; &
  • The need to change spectacles or contact lenses frequently.

How is a cataract removed?

Cataracts are removed by a surgical procedure whereby the clouded lens is removed and replaced with an artificial one.

There are two procedures:

  • Phaco-emulsification:- A small incision is made on the side of the cornea. The ophthalmologist then inserts a small ultrasonic probe into the eye which emits ultrasound waves. These waves break up the cataract and aspirate the material. The incision is very small, there is no need for stiches and will heal by itself over a very short period of time.
  • Extra-capsular surgery (seldom used):- A slightly longer incision is made on the side of the cornea and the hard centre of the lens is removed. What is left of the lens is then removed by suction. Sutures are then used to close up the wound.

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.

Important points to keep in mind

  • Continue to take any medicines you have been prescribed when you come for surgery, but notify your surgeon if you take any anti-coagulant (blood-thinning) medication.
  • Remove soft contact lenses at least one week and hard lenses two weeks before surgery.
  • Do not wear make-up on the day of surgery. Resume eye make-up after two weeks.
  • If both eyes have to be operated on, the second operation should be performed one week later.
  • Resume normal activities as soon as you wish.
  • Your eye won't reject the lens implant because the IOL is not human tissue.
Lasik (EXCIMER LASER)

Introduction

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.

Is LASIK for me?

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.

What are the success rates?

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.

Treatment

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.

Macular holes

Introduction

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

Symptoms may vary depending on whether the hole is of partial or full-thickness.

  • Distorted, "wavy" vision.
  • Blurred central vision.
  • Decreased central vision for both distance and reading activities.
  • Grey area in central vision.
  • Central blind spot.

Treatment

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.

M-acute angle-closure glaucoma

Description

  • Acute glaucoma is a disease in which there is a sudden increase in the pressure in the eye
  • This usually occurs in one eye and is associated with sudden loss of vision
  • Acute glaucoma happens when the liquid in the eye is unable to drain correctly
  • It is more common in an older person who is long-sighted.
  • Symptoms include severe pain in the eye, decreased vision and sometimes nausea and vomiting
  • Initial treatment is aimed at lowering the pressure inside the eye
  • The final treatment is by laser or surgery to prevent the problem from recurring

What is acute angle-closure glaucoma?

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.

What causes acute angle-closure glaucoma?

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.

Who gets acute angle-closure glaucoma and who is at risk?

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.

What are the symptoms and signs of acute angle-closure glaucoma?

Symptoms include:

  • Decreased vision - the person can often only count fingers held right in front of the face.
  • Severe pain in the eye, described as a deep ache in and around the eye.
  • Nausea and vomiting are common.

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.

How is acute angle-closure glaucoma diagnosed?

The appearance of the eye can allow the doctor to make a diagnosis.
The intraocular pressure is raised, often to around 60 mm Hg.

Can acute angle-closure glaucoma be prevented?

This disease can be prevented if an eye at risk has a minor laser procedure called a laser iridotomy.

How is acute angle-closure glaucoma treated?

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.

When to see your doctor

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)

M-Iritis

Summary

  • Iritis is the inflammation of the iris and sometimes the ciliary body as well.
  • This usually occurs in only one eye.
  • If treated correctly and sufficiently early, iritis does not result in permanent damage.
  • In many cases, the cause of iritis is unknown.

What is iritis?

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.

What causes iritis?

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 and signs of iritis

Symptoms of iritis include:

  • Eye pain
  • Sensitivity to light
  • Redness of the eye typically around the cornea
  • Watering of the eye
  • Blurred vision
  • Floating spots in the field of vision
  • A smaller pupil in the affected eye (occasionally)

Generally, the eye is not sticky or crusty. These symptoms are more suggestive of conjunctivitis.

How is iritis diagnosed?

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.

How is iritis treated?

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.

What is the outcome of iritis?

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.

When to call the doctor

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)

Retinal detachment

Introduction

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.

Who are most susceptible?

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.
Symptoms
A shadow/curtain/veil spreading across the vision of one eye (most common)

  • Spots or flashes of light
  • "Wavy" or "watery" vision
  • Showers of dark spots called floaters
  • Sudden decrease of vision

Treatment

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.