Patient Information

Developments in materials and designs of contact lenses are constantly changing as newer technology improves on previous contact lenses. Recent developments include toric (astigmatism-correcting) lenses which are replaced on a daily basis and the development of lenses which allow enough oxygen to pass through the lens that they can be worn on an overnight basis.

Disposable contact lenses

Disposable contact lenses are lenses which are designed to be replaced on a regular basis, usually either daily, two-weekly or monthly. The more often a lens is replaced, the less the lens will become deposited with proteins and oils. Many of the problems that contact lens wearers experienced when contact lenses were replaced on an annual or two yearly basis are seldom seen nowadays. Disposable contact lenses are therefore a healthier alternative. Daily disposable contact lenses are a great option for people who only want to wear their contact lenses a few times per week, for example, for sport. They also remove the need for cleaning, since they are inserted in the morning (or before you play sport) and then thrown away afterward, offering exceptional convenience and good value for money. Lenses which are replaced two-weekly or monthly are good value if you want to wear lenses everyday. They work out to be cheaper than daily disposable over the period of two to four weeks, although you will need to clean them nightly.

Leave-in (extended wear) contact lenses

Leave-in (extended wear) contact lenses are designed to be worn continuously for 30 days and nights and then replaced with a new contact lens. They offer the ultimate in convenience, since they usually don't need removing or mechanically cleaning. Other advantages include being able to see without struggling to find your glasses if you get up in the night, or not having to worry about removing lenses with dirty hands if you go camping. You also won't need to remember to carry bottles of solutions around with you if you go out with friends and end up staying out the night!

Gas permeable contact lenses

Gas permeable contact lenses are usually used for the correction of moderate levels of astigmatism. They provide excellent clarity of vision, especially in cases where the astigmatism is irregular (such as with keratoconus). They require a longer period of adaptation than soft lenses.Gas permeable contact lenses offer excellent long-term corneal health since they allow almost as much oxygen to pass through to the cornea as without a lens on the eye. Many of the problems associated with the reduced oxygen flow through the old-style "hard lenses" are seldom seen nowadays due to the developments in these modern gas permeable materials.

Myopia

Myopia (also called short-sightedness) is a condition in which the eyeball itself is either too long, or the front of the eye (the cornea) is too curved, or a combination of both. The result is that light from distant objects is focussed in front of the retina (instead of on the retina). This makes doing things like driving and reading far-off signs difficult. Myopia can be corrected with either soft (disposable) contact lenses or RGP (gas permeable) contact lenses.

Hyperopia

Hyperopia (also called hypermetropia or long-sightedness) is a condition in which the eyeball is too short, or the cornea is too curved, or a combination of both. The result is that light from objects is focussed behind the retina. We can use some of the focussing power of the natural lens within the eye to help refocus the light, but this can lead to "eyestrain" or tired eyes, especially when working at near. The focussing ability of the eyes also reduces as we get older, making it more difficult to overcome the focussing problem. Hyperopia can be corrected with either soft (disposable) contact lenses or RGP (gas permeable) contact lenses.

Presbyopia

Presbyopia is the loss of focussing ability of the eyes. The focussing lens inside the eye hardens as we get older, resulting in the closest point that we can focus on moving further and further back until reading small print becomes more and more difficult. This is why many people who have never worn spectacles find that they need a pair of reading spectacles when they reach their mid-forties. There are a number of contact lens designs available now which offer an alternative to glasses if you are having problems with your reading vision due to presbyopia.

Astigmatism

Astigmatism is a condition in which the front of the eye (the cornea) is oval shaped instead of round. Some people describe it as having rugby ball shaped cornea instead of a soccer ball shaped cornea. There are two types of astigmatism, regular and irregular. Regular astigmatism is able to be corrected with glasses, soft (toric) and RGP (gas permeable) contact lenses.

The range of contact lenses available to correct regular astigmatism is constantly increasing. Many people with astigmatism have been told in the past that their eyes aren't suitable for contact lenses, due to limited designs available at the time. You should consult your eye-care practitioner to find out if you may be able to be fitted now with the increased ranges of contact lenses.

Irregular astigmatism is usually not well corrected with spectacles or soft contact lenses, unless it is fairly mild. It can be caused by conditions such as keratoconus and corneal scarring. RGP (gas permeable) contact lenses correct the vision by maintaining their shape on the cornea, with any corneal irregularity being filled by the tears behind the lens. Soft contact lenses, when tried with irregular astigmatism, tend to mould to the shape of the eye, thus transferring the distortion.

Keratoconus

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Keratoconus is a condition where the cornea thins and then slowly pushes forward in a cone shape. If an eye with astigmatism is described as a rugby ball lying on it's side, think of a cornea with keratoconus as a rugby ball with the pointed end facing forward. Early cases will often still see well with spectacles or soft contact lenses, but as the condition progresses, RGP (gas permeable) lenses are needed to better correct the distortion in vision.

Many new designs of gas permeable lenses are available for the correction of keratoconus, including large diameter contact lenses which can offer better centration and comfort than traditional lenses.

Meibomian Gland Dysfunction

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Computer Vision Syndrome

When we perform concentrated vision tasks such as driving, reading and working on computers, we tend to blink less often than normal. This can result in the drying out of contact lenses, which can make the contact lenses less comfort, as well as blurring the vision. This can be managed by applying rewetting eye drops to rehydrate the lenses as often as needed. Improving the quality and frequency of blinking can also help enormously. Newer materials are also available which dry out less, especially if there is also air-conditioning around, which can further dry out your contact lenses. You should consult your eye care practitioner if you are experiencing any discomfort with your contact lenses. Remember that your lenses should offer clear, comfortable and healthy vision.

Dry Eyes and contact lenses

Many newer contact lens materials are available nowadays which offer better comfort to people with dry eyes than previous lens materials. Specially designed polymers have been developed which dry out less on the eye, resulting in less lens awareness, better clarity of vision and less reliance on rewetting drops. See your eye care practitioner to find out if you are suitable for one of the newer material type of contact lenses.

Blepharitis

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By far the best way to decide on whom you choose to provide your contact lens care is by word of mouth referral. If you know someone who has successfully worn contact lenses for some time, and their eyes look clear and healthy, they are most likely obtaining the correct and necessary level of care. If they are enthusiastic about their contact lenses and the skills of their eye care practitioner then you will probably be too. Look at the lists on the linked pages for more information. Remember that price and convenience may not be the best reasons to risk your most important asset, your vision!

What price would you place on your vision?

A number of exciting new developments have recently occurred in contact lens practice. Hundreds of millions of dollars have been spent on R&D and refining these fantastic designs. Take a look at the sites on the links pages for definitions of terminology, more information and the manufacturers sites for more details regarding these new lenses.

• A revolutionary hybrid material for soft lenses with added silicone [silicone-hydrogels] has meant the potential for delivering up to six times more oxygen to the eye than previously possible with existing soft lens materials. This means improved tolerance to long hours of contact lens wear by the eye tissues, and the potential to be able to sleep in these specialised contact lenses. Two brands of lenses made with these materials have been released and show great potential.
• A new soft disposable bifocal contact lens has been released, with a 'pupil intelligent' design. This lens is designed to work in different light levels, and comes in a wide range of prescriptions, offering greater success than previously possible.
• More versions of disposable soft lenses to correct astigmatism are becoming available for both short sighted [myopic] and long-sighted [hyperopic] prescriptions. This enables inexpensive contact lens correction of vision coupled with higher oxygen delivery to the eye than previously possible. At the same time advanced RGP designs and manufacturing techniques, offer even better solutions for astigmatism than previously possible.
• One-day, disposable soft lenses: Wear the lenses for a day, and then throw them away. No solution hassles, and great for people who want convenience and comfort. Especially good for occasional or part-time wear, sport and so forth.
• Contact lenses for keratoconus: New Zealand designed rigid contact lenses are leading the world in optically correcting keratoconus [conical cornea]. Keratoconus is best corrected by rigid contact lenses - rather than spectacles - due to the irregular shape of the cornea. The Rose K design developed in Hamilton by Optometrist Paul Rose is now available in forty-two countries. The computer-designed and generated back surface enhances fitting, thus optimising comfort and vision.
• Coloured [cosmetic] contact lenses: New multi-layered coloured contact lenses are available to give an even more natural appearance. Most people's eyes are a mosaic of colours, and past efforts at changing eye colour with contact lenses have often resulted in a slightly artificial or monotone appearance. Now you can alter your eye colour with a more natural result.

People wear contact lenses for various reasons.

Contact lenses typically provide better vision than spectacles for some visual conditions such as severe short-sightedness [myopia], long-sightedness [hyperopia], astigmatism, corneal distortion, or after cataract removal [aphakia].

Some people like the wider field of view provided by contact lenses, as side vision [peripheral vision] is often blocked, obscured or limited by spectacle frames. Contact lenses do not fog up with changes in temperature - or from perspiration - and they are unaffected by rain.

Many people choose contact lenses because they think glasses make them look less attractive or they find spectacles annoying. Sports players and people involved in vigorous activities often find contact lenses more convenient than spectacles, especially for water sports and contact sports. Priests, psychologists and many others also find that contact lenses avoid the barrier effect that spectacles may cause, thus leading to more direct eye-contact. http://www.contactlenses.org/clsglasses.htm

Many unsuccessful wearers who cut corners on their eye health and contact lens care spend more money on servicing their cars, clothes, cosmetics and at the pub than what they save by cutting out on their eye care! [You cant enjoy your car, or most things in life if you compromise your vision through poor eye care.] One question you need to ask yourself is: How many times do you need to permanently or temporarily damage your vision before it's too late? The answer? Less than once!

There are always know it all's that denounce good advice, ridicule regular eye care, spit on their lenses [yes, there are those who do!] and refuse to accept that an up to date, backup pair of spectacles are necessary for emergencies, and to give the eyes the occasional time out for a breather from contact lenses. Guess who complain the hardest when that they can't drive, can't work, can't see and suffer days or even weeks should they need to be hospitalised or suffer an infection or other circumstance that necessitates the temporary [or permanent] discontinuation of contact lens wear? It's especially a problem for a commission based sales person dependant on their car for earning a living. All the more so these days where a certain minimum level of vision is required to obtain a drivers licence. The more complex the visual problem the more critical this may be. See the case report from an ex-contact lens wearer!

For those of you who doubt the need for proper contact lens care and compliance, here follows the personal experience of someone who is now an Optometrist and in fact a respected member of the contact lens fraternity and president-elect of the NZSCLP!

The Importance of Compliance

I first started wearing contact lenses in my final year of high school. They allowed me a greater amount of freedom for my sporting pursuits, as well as having obvious cosmetic benefits. My optometrist was very particular to outline the appropriate handling procedures and cleaning regime, stressing the importance of being compliant in my management of the contact lenses.

The lenses provided no problems for the first year and a half, with fairly constant wear in this period, and the occasional night of sleeping in the lenses [against the advice of my optometrist!]. By this stage I was at University and starting to feel some financial strains, so I started to store my lenses in the same solution for two days. I bypassed the digital rub step and did not use protein tablets at all. I also started sleeping in my lenses over the weekends. At no stage did I consider that I could be harming my eyes, as the comfort of the lenses was still all right and my vision still seemed to be satisfactory. In fact I hadn't seen my optometrist for a routine check in over 18 months.

I often wish I knew then what I know now regarding contact lens complications. I ended up getting a viral infection in my eyes, which I really struggled to shake for over four months. I have an intolerance to contact lens wear now, and can only wear contact lenses for a maximum of 6 hours before I get red, irritated & gritty eyes! So much for the cosmetic benefits of contact lenses, as I now have to rely mostly on spectacles! All of this could have been avoided if I was more compliant with my cleaning, replaced my solutions daily, removed my lenses at night and had regular visits to my eye-care practitioner!!

He was studying a Science degree at the time and was consulting a well know South Island optometrist who was managing his recovery from the viral infection. They had some discussions about optometry as a career and he asked "Is it boring?" That's how he became involved and today will tell you that optometry and contact lens practice is far from boring and in fact helping people see is a very stimulating and satisfying profession.

'Lens Calculi' often referred to as 'jelly bumps' on the surface of a soft lens. These deposits often cause discomfort and have the potential to cause abrasions, allergic lid reactions and can lead to the binding of bacteria, fungi and other nasties with potentially sight threatening sequelae!

Some handy tips for safe, comfortable contact lens wear:

• Never wear lenses longer than prescribed. Do not wear daily lenses while sleeping.
• Do not wear your lenses overnight unless recommended by your contact lens practitioner. Overnight wear of contact lenses increases the risk of complications.
• Always wash, rinse, and dry your hands before handling lenses. Avoid pump and moisturising soap and use lint free cotton towels and tissues.
• Do not use saliva to wet your lenses. Do not put lenses in your mouth.
• Use only approved contact lens solutions for lubricating or wetting your lenses.
• Always use fresh solutions in your lens case when disinfecting your lenses.
• Ask your contact lens practitioner about wearing lenses during water activities and other sports. In some cases alternative lenses may be prescribed for sport, other hobbies and activities.
• Schedule and keep follow-up appointments with your contact lens practitioner.
• Never use non-sterile home-prepared saline. The use of home-prepared saline with contact lenses has been associated with serious infections.
• Contact lens storage cases can be a source of bacteria and other microbial growth. Lens cases should be cleaned, rinsed, and allowed to air dry each time the lenses are removed. Replace the lens case frequently. Household bleach is an excellent disinfectant for contact lens cases but make sure the case is compatible with this and rinse and dry the case thoroughly.
• If your eyes become red, irritated, painful, abnormally light sensitive or if your vision worsens while wearing lenses, immediately remove the lenses and consult a contact lens practitioner.
• Do not get lotions, creams, sprays or chemicals in your eyes or on your lenses. It is best to insert lenses before applying make-up and remove them before removing make-up. Water-based and gel-based cosmetics are less likely to damage lenses than oil-based products. Do not apply eyeliner on the inside rim of the eyelids.

  Make-up and cosmetics, especially inner lid margin eye-liner can block the numerous meibomian glands, cause stasis, infections, discomfort and lens deposits, as illustrated. Eye care practitioners can and do recommend the appropriate methods/cosmetics/application to minimise such reactions. Make-up counter assistants/advisors must be aware of these potential problems when recommending cosmetics, eye shadow, foundation, mascara, sun block and moisturisers!

  Cosmetics should be discarded and replaced with new, fresh make-up, according to manufacturers recommendations as old, expired make-up has been shown to harbour various bacteria, fungi and other micro-organisms thus dramatically increasing the risk of eye infections!

• You should have eye examinations every six to 12 months or as recommended by your contact lens practitioner.
• Contact lenses wear out with time and should be replaced regularly.
• Disposable lenses should be thrown away after the recommended wearing period prescribed by your contact lens practitioner. Daily disposable lenses should not be re-used.

Some useful tips on contact lenses: Do's and don'ts, cosmetics [make-up] and contact lenses and more from the respected Cornea and Contact Lens Research Unit [CCLRU] in Sydney, Australia.
http://www.cclru.org/eye_information/index.asp

• Different solutions cannot always be used together and not all solutions are safe for use with all lenses. Use only the lens care solutions recommended by your contact lens practitioner, and do not change brands without first consulting your contact lens practitioner.
• Follow directions in the package inserts for the use of contact lens solutions.
• There are three essential steps in contact lens care
  1. Cleaning
  2. Rinsing
  3. Disinfecting
• Every time contact lenses are removed, they must be cleaned, rinsed, and disinfected before wearing again. Some solutions are designed to perform more than one of these functions, but may not be as effective.
• Always remove, clean, rinse, enzyme and disinfect your lenses according to the schedule of your contact lens practitioner.
• The use of an enzyme or any cleaning solution does not substitute for disinfection.
• Lenses stored longer than 12 hours may require cleaning, rinsing and disinfecting again before use. Consult the package literature or your contact lens practitioner for specific instructions.

A central corneal scar on a final year medical houseman's cornea following a bacterial ulcer that developed after he re-used a disposable lens that had been left soaking for months in unpreserved saline. [He had re-used it (against instructions) following damage to his regular lens, which had caused a minor abrasion.] He thus introduced the bacterially contaminated lens to his eye [ex the unpreserved saline storage]. The bacteria thus penetrated his damaged corneal epithelium, caused an ulcer and one of his medical colleagues erroneously treated a bacterial ulcer with cortisone eye drops thus exacerbating his ulcer. Fortunately we caught it before he suffered permanent visual loss - a potentially career threatening, yet avoidable problem.

The moral of the story? If even medical experts can make such a mistake how can we expect an untrained assistant to be able to give advice on such matters as lens care and treatment? Always consult an optometrist or ophthalmologist if you have any signs of red, sore, light sensitive eyes or abnormal symptoms or visual problems!

Always refer red eyes and contact lens complications to an optometrist or ophthalmologist who are the only people who have the necessary skills, microscopes, equipment and experience to correctly diagnose, refer or treat such problems!

• Cleaning solutions remove dirt, protein, oils, mucus, and debris that get on the lens during wear.
• Disinfecting solutions kill bacteria and other germs on the lenses. Disinfection is necessary to help prevent serious eye infections.
• Rinsing solutions remove other solutions from the lenses. They also prepare the lenses for wear.
• Enzyme solutions remove protein and other deposits that accumulate on the lenses over time.
• Rewetting solutions are used to wet [lubricate] the lenses while you are wearing them, to make them more comfortable.
• Never use unpreserved saline from a bulk container. Only single dose unpreserved saline may be used.
• If preserved saline is not available then purchase either unit-dose unpreserved saline or aerosol saline solution.
• Some solutions may have more than one function, which will be indicated on the label. Read the label on the solution bottle.
• Keep solution containers tightly closed and upright in a clean, dry, cool place when not in use.
• Solutions may become contaminated after opening. Throw away opened solutions as recommended. Do not use solutions after their expiry date.
• Remember the expiry date refers to the unopened container.
• Pay scrupulous attention to hygiene when handling the bottle tip and lid. Never touch the tip of the container with any other surface including fingers, and always handle the bottle lid with dry hands.
• Do not put solutions directly in the eye, unless they are designed for that purpose. Make sure you don't put cleaners or disinfecting solutions in the eye, by mixing up the bottles.

This image shows a lens that was thermally disinfected in scorbic acid preserved saline. The scorbic acid discoloured a normally perfectly transparent soft lens. This represents one of the myriad problems associated with pharmacy assistants [and others] 'selling/recommending' incorrect/improper lens care products. Only the prescriber has the knowledge to recommend the correct modality/care regimen for the wearer and this should never be altered except in consultation with a registered contact lens practitioner. A small chip is also visible on the left hand edge of the lens which can lead to discomfort and possible irritation/inflammation or even infection of the sensitive ocular tissues.

This image shows how an RGP lens has been used to rehabilitate vision in a patient who had undergone Radial Keratotomy [RK], an early version of refractive surgery.

The fine radial cuts can be seen radiating out from the centre of the cornea, behind the lens. This form of surgery has demonstrated a tendency to over-correct vision usually resulting in hyperopic astigmatism and irregular, distorted corneas - some years after the surgery - which was performed to correct myopia.