Keratoconus (from Greek: kerato- horn, cornea; and konos cone), is a degenerative disorder of the eye in which structural changes within the cornea or front surface of the eye cause it to thin and change to a more conical or cone-like  shape than its normal gradual curve. Keratoconus has been known to be called “bulging-eyes.”

People suffering from keratoconus may complain about the following symptons:

• distorted vision with multiple images
• streaking of their vision
• Sensitivity to light (also known as photophobia)
• difficulty with driving at night 
• Eye strain 
• Itching of the eyes associated with no pain

Keratoconus is usually diagnosed in the teenage years when vision trouble affects the learner at school but can also be missed if in it’s early stages and rather be diagnosed as a simple astigmatism.

For people with astigmatism, objects both near and far appear distorted. This occurs because some of the light rays are focussed and others are not. Astigmatism is a very common refractive error found by optometrists and or ophthalmologists.

Keratoconus is typically diagnosed in the patient’s adolescent years as mentioned above and attains its most severe state in the twenties and thirties. If both eyes are afflicted, the deterioration in vision can affect the patient’s ability to drive a car or read normal print. In most cases, corrective lenses are effective enough to allow the patient to continue to drive legally and likewise function normally. Further progression of the disease may require surgery including corneal transplantation. However, despite the disease’s unpredictable course, keratoconus can often be successfully managed with little or no impairment to the patient’s quality of life.

Keratoconus is the most common dystrophy of the cornea, affecting around one person in a thousand. It seems to occur in populations throughout the world, although it occurs more frequently in certain ethnic groups. The exact cause of keratoconus is uncertain, a genetic link seems likely, as the incidence rate is greater if a family member has been diagnosed. The progression of keratoconus is rapid in patients having Down syndrome.

Diagnosis
 
A schematic digram showing change in cornea

Prior to any physical examination, the diagnosis of keratoconus frequently begins with an ophthalmologist’s or optometrist’s assessment of the patient’s medical history, particularly the chief complaint and other visual symptoms, the presence of any history of ocular disease or injury which might affect vision, and the presence of any family history of ocular disease. An eye chart, such as a standard Snellen chart of progressively smaller letters, is then used to determine the patient’s visual acuity. The eye examination may proceed to measurement of the localised curvature of the cornea with a manual keratometer, with detection of irregular astigmatism suggesting a possibility of keratoconus. A further indication can be provided by retinoscopy, in which a light beam is focused on the patient’s retina and the reflection, or reflex, observed as the examiner tilts the light source back and forth.

Treatment
Contact lenses
 
Rigid gas permeable lens for keratoconus

In early stages of keratoconus, glasses or soft contact lenses can suffice to correct for the mild astigmatism. As the condition progresses, these may no longer provide the patient with a satisfactory degree of visual acuity, and most clinical practitioners will move to managing the condition with rigid contact lenses, known as rigid gas-permeables, or RGPs. RGP lenses provide a good level of visual correction, but do not arrest progression of the condition.

In keratoconic patients, rigid contact lenses improve vision by means of tear fluid filling the gap between the irregular corneal surface and the smooth regular inner surface of the lens, thereby creating the effect of a smoother cornea. Many specialized types of contact lenses have been developed for keratoconus, and affected people may seek out both doctors specialized in conditions of the cornea, and contact lens fitters who have experience managing patients with keratoconus. The irregular cone presents a challenge and the fitter will endeavour to produce a lens with the optimal contact, stability and steepness.

Traditionally, contact lenses for keratoconus have been the ‘hard’ or rigid gas-permeable variety, although manufacturers have also produced specialized ’soft’ or hydrophilic lenses and, most recently, silicone hydrogel lenses. A soft lens has a tendency to conform to the conical shape of the cornea, thus diminishing its effect. To counter this, hybrid lenses have been developed which are hard in the centre and encompassed by a soft skirt. Soft or hybrid lenses do not however prove effective for every patient.

Some patients also find good vision correction and comfort with a “piggyback” lens combination, in which gas permeable rigid lenses are worn over soft lenses, both providing a degree of vision correction. One form of piggyback lens makes use of a soft lens with a countersunk central area to accept the rigid lens. Fitting a piggyback lens combination requires experience on the part of the lens fitter, and tolerance on the part of the keratoconic patient.

Scleral lenses are sometimes prescribed for cases of advanced or very irregular keratoconus; these lenses cover a greater proportion of the surface of the eye and hence can offer improved stability. The larger size of the lenses may make them unappealing or uncomfortable to some, however their easier handling can find favour with patients with reduced dexterity, such as the elderly.

Surgical options

• Corneal transplant
• Corneal ring segment inserts
• Radial keratotomy

Reference:
1) www.bausch.co.za
2) www.wikipedia.co.za
3) Kanski JJ 3rd edition McMillan & Partners

Allergies can trigger other problems, such as conjunctivitis (pink eye) and asthma. Most of the more than 22 million Americans who suffer from allergies also have allergic conjunctivitis, according to the American Academy of Ophthalmology.

COMMON SIGNS OF ALLERGIES INCLUDE: red, swollen, tearing or itchy eyes; runny nose; sneezing; coughing; difficulty breathing; itchy nose, mouth or throat; and headache from sinus congestion.

WHAT CAUSES EYE ALLERGIES?

Many allergens are in the air, where they come in contact with your eyes and nose. Airborne allergens include pollen, mould, dust and pet dander. Other causes, such as certain foods or bee stings, do not typically affect the eyes. Adverse reactions to certain cosmetics or drugs such as antibiotic eye-drops also may cause eye allergies.

TREATMENT

Avoidance. The most common “treatment” is to avoid what’s causing your eye allergy. Itchy eyes? Keep your home free of pet dander and dust, and stay inside with the air conditioner on when a lot of pollen is in the air. Air conditioners filter out allergens, though you must clean the filters from time to time.

Medications. If you’re not sure what’s causing your eye allergies or not having any luck avoiding them, your next step will probably be medication to alleviate the symptoms. Over-the-counter and prescription drugs each have their advantages.

It’s important to discuss the problem with your doctor, so the cause of the problem can be treated and cleared up. Constant use of products that only treat the symptoms, may make the problem worse over time.

HAVE YOUR EYES TESTED REGULARLY

Regardless of your age or physical health, it’s important for everyone to have regular eye exams.

When an eye doctor examines your eyes, he is doing more than checking to see if you need glasses. During a complete eye exam, your eye doctor also checks for common eye diseases, symptoms of any other diseases, assess how your eyes work together as a team and evaluate them as an indicator of your overall health.

EYE TESTS ARE AN IMPORTANT PART OF HEALTH MAINTENANCE FOR EVERYONE.

Adults should have their eyes tested to keep their prescriptions current and to check for early signs of eye disease. For children, eye exams can play an important role in normal development.

Vision is closely linked to the learning process. Children who have trouble seeing or interpreting what they see will often have trouble with their schoolwork. If your child performs poorly at school or exhibits a reading or learning disability, be sure to have his eyes examined to rule out an underlying visual cause.

9 STEPS TO REDUCING COMPUTER EYESTRAIN

Computer eyestrain is the number one office-related health complaint, but there are many things workers and employers can do to reduce this symptom of computer vision syndrome (CVS). Here are nine easy tips:

1. Get a computer eye exam.

This is the most important thing you can do to prevent or treat computer vision problems. Computer users should have an eye exam before they start working on a computer and once a year thereafter.

2. Use proper lighting.

Eyestrain is often caused by excessively bright light coming in from outside and excessively bright light inside. When you use a computer, your ambient lighting should be about half that used in most offices. Eliminate exterior light by closing drapes, shades, or blinds. Reduce interior lighting by using fewer light bulbs or fluorescent tubes, or use lower intensity bulbs and tubes. If possible, position your monitor so that windows are to the side of it, instead of in front or back.

3. Minimize glare.

Glare on walls and finished surfaces, as well as reflections on the computer screen itself can also cause eyestrain. You may want to install an anti-glare screen on your monitor and, if possible, paint bright white walls a darker color with a matte finish. Again, cover the windows; when outside light cannot be reduced, use a computer hood. Have an anti-reflective coating applied to your glasses. This will prevent glare and reflections on the back side of your lenses from reaching your eyes.

4. Adjust the brightness of your computer screen.

Closely match the brightness of the environment with that of your computer screen, by using the buttons on the monitor. As a test, try looking at the white background of this web page: if it looks like a light source, it’s too bright; if it seems dull and gray, it may be too dark. Also adjust the monitor to make sure the contrast between the screen background and the on-screen characters is high. And make sure that the text size and color are optimized for the most comfort.

5. Blink more often.

Blinking is very important when working at a computer — it rewets your eyes to avoid dryness and irritation. When working at a computer, people blink less frequently — about five times less than normally, according to studies. Tears coating the eye evaporate more rapidly during long non-blinking phases and cause dry eyes. Office buildings may have excessively dry environments that also reduce tearing.

For significant problems, ask your eye doctor about artificial tears or eyedrops that you can use during the day. By the way, don’t confuse lubricating drops with the drops that only “get the red out.” The latter can indeed make your eyes look better with vasoconstrictors that reduce the size of the blood vessels in your eyes, but they are not necessarily formulated to help with dryness and irritation.

Also try this exercise: Every 30 minutes blink 10 times by closing your eyes as if falling asleep (very slowly). This will help rewet your eyes.

Information made available by ICAS. Contact them on 0800 611 191 or www.icas.co.za

Eye Care

Retha van der Walt

B.Optom (RAU) FOA (SA)

Intro

Contact lenses are among the safest forms of vision correction when patients follow the proper care and wearing instructions provided by their Optometrist. However, when patients do not use lenses as directed, the consequences may be dangerous. In fact, contact lens wearers could be damaging their eyes by not using proper hygiene in caring for their lenses

Clean and safe handling of contact lenses is one of the most important measures contact lens wearers can take to protect their sight. Exercising optimal care and hygiene with contact lenses can keep the eyes healthy.

There are different kinds of contact lenses available, depending on your eye’s prescription and shape, your Optometrist will prescribe the best contact lens for you.  The most popular lenses in South Africa at the moment are monthly disposable contact lenses.  There are also specific contact lenses available that you can sleep with for up to 30 days.  Please ensure that the client discuss this with their Optometrist before they sleep with your lenses!

Helpful Hints for Contact Lens Wearers (courtesy of www.bausch.co.za)

The following may be recommended to clients:

• Always wash and rinse your hands before handling contact lenses
• Do not use a contact lens if the sterile blister package is opened, damaged or expired
• Never wear contact lenses that are torn or damaged as you can damage your cornea
• You should be adept at lens removal before leaving your eye care practitioner
• Remove lenses immediately if eyes become red or irritated
• Always handle contact lenses carefully and avoid dropping them. Never use your finger nails to pick them up
• Do not get cosmetics, lotions, soaps, creams or deodorants on your lenses
• Make-up should only be applied once you have inserted your lenses – water based products are less likely to damage lenses than oil-based ones
• If aerosol products, such as hair spray are used while wearing your lenses, keep your eyes closed while using the spray and until it has settled
• Avoid harmful or irritating vapours and fumes while wearing lenses
• Ensure that your hands are free from foreign materials before handling your lenses, as this may cause microscopic scratches on the lens
• Carefully follow handling, insertion, removal and wearing instructions and those prescribed by your eye care practitioner
• Never wear contact lenses beyond the period recommended by your eye care practitioner
• Ask your eye care practitioner about wearing lenses during sporting activities, especially swimming
• Never use tweezers or other tools to remove your lenses from the lens container unless specifically indicated for that use. Slide the lens up the side of the lens container
• Clean the lens case every week (leave to air dry) and replace every 6 months
• Always contact your eye care practitioner before using any ointment / eye drops in your eyes whilst wearing lenses
• It is important to inform your employer of being a contact lens wearer as some jobs may require use of protective eyewear or may require that you not wear contact lenses at all
• Certain medications, such as anti-histamines, decongestants, diuretics, muscle relaxants, tranquillisers and those for motion sickness may cause dryness of the eye, increased lens awareness or blurred vision
• Oral contraceptive users could develop visual changes or changes in lens tolerance when using contact lenses
• Tap water must never be used in conjunction with contact lenses
• Contact lens care products should never be mixed
• Contact lens wearers should consult their Optometrist should they experience any problems
• Follow-up visits to your eye care practitioner are necessary to ensure the continued health of your eyes
• Healthy Eyes are essential for good sight. Don’t put this at risk through neglect
• Clean the lens case every week (leave to air dry) and replace every six (6) months
• Check the preservatives in eye drops or ointments prior to use with contact lenses. Should eye drops or ointments be used, remove contact lenses. Eye drops can safely be placed on eyes, wait 20 minutes for absorption and place lenses back on eye.

There are different types of contact lens solutions on the market.  Most of the solutions available in South Africa are multipurpose solutions.  We will now discuss how clients can clean their lenses with these solutions.  It is however, very important to read the instructions on their solution, as directions may vary. One’s cleaning regimen can also vary depending on what type of contact lens one wears.

How to clean contact lenses

The following should be recommended to clients:

• Wash your hands and dry them with a lint-free towel
• Fill your clean lens case with contact lens solution
• Remove your right contact lens from your eye, place the lens in the palm of your hand and apply a few drop of solution to your lens. Rub the lens gently for 10 seconds on each side
• Rinse the lens free from debris with fresh solution
• Place lens in the appropriate compartment of the lens case. Secure the lens case cap
• Repeat with the left lens
• To disinfect your lenses, store in the lens case in solution overnight or for at least 4 hours.

Conclusion

Regular eye examinations are crucial for contact lens wearers.  Contact lens materials and solutions can affect the eye in different ways.  It is important that the health of the corneas is checked regularly.  If the client experiences any discomfort, redness or pain when wearing contact lenses, they are to remove their lenses and contact their Optometrist immediately.