HARD GAS PERMEABLE LENSES are made from plastic and are curved to match the cornea. They cover the central part of the cornea and are held in place by the surface tension of the tears. These are available in materials that enable them to be worn for up to 30 days sleeping.
SOFT CONTACT LENSES are made of a soft, flexible plastic material and cover the whole of the cornea. The type of lens that is finally prescribed depends on the need and suitability of the patient for a particular lens type. Two types exist; CONVENTIONAL SOFT LENSES, which last 2 years, as well as DISPOSABLE CONTACT LENSES which are worn for periods between one day and four weeks (being removed at night), and then discarded. The period of wear is dependent upon the material.
New Contact Lenses wearers should adopt a responsible, patient and determined attitude to wearing and handling their lenses. The lenses are susceptible to damage through careless handling, and because of their size can be lost if care is not taken. The risk of loss is greatest during the initial period, and special care must be taken during this time.
New contact lens wearers should be aware that despite consideration of all the necessary factors in the fitting of contact lenses some people are unable to satisfactorily wear lenses on a long-term basis. Every effort is made to determine this in the initial fitting procedures. If however, after delivery of the lenses this situation arises, appropriate steps will be taken to overcome the problem but no refund is available on lenses. The optometrist may exchange the lenses for spectacles.
The number of visits you will be asked to attend will vary depending on the type of lens fitted. In some cases, several visits may be necessary. A typical schedule would be as follows;
(i) Routine optometrical examination
(ii) Visits for additional measurements and fitting of lenses
(iii) Prescribing and ordering of lenses
(iv) Delivery of lenses, instructions on insertion/removal, lens care and maintenance.
Advice on wearing schedules
(v) Aftercare visits
When regular contact lens wear is achieved, there still remains the responsibility of having your eyes and lenses checked regularly by a contact lens fitting practitioner. Regular aftercare is an important part of the contact lens fittings and prescribing both from the patients and the practitioners’ point of view. At these visits the practitioner checks the state of health of the eyes, evaluates the performance and fitting of the lenses and discusses any problems the patient may have. Sometimes minor adjustments will be made to the lenses to improve their performance and occasionally the lenses may have to be refitted.
A typical schedule following delivery of lenses might be;
AFTERCARE EXAMINATION - 2 weeks later
- 4 weeks later
- 6 weeks later
- 3 months later
- 6 months later
- 12 month intervals
LENS CARE AND MAINTENANCE
If significant bacterial contamination is introduced into the eye an infection may result. Therefore strict hygiene in handling contact lenses is essential. Reports of any serious complications associated with contact lenses are rare but invariably the cause of these rare cases has been traced to some serious neglect by the patient of the instructions on hygiene, wearing schedules or maintenance procedures.
Before handling contact lenses wash your hands thoroughly ensuring that the sides of the fingers and the palms are cleaned. Ensure that your fingers are free of lint, cosmetics, hand lotions, hair oils, nicotine etc.
Contact lenses are made of plastic materials and if handled carelessly they may be scratched, distorted, chipped or split. Do not slide or scrape a lens across a tabletop and be sure that your fingernails do not scratch the surface or dent the edge of the lens. If the lens is accidentally squashed or jammed in its case or elsewhere, be sure to inspect the lens carefully.
If you suspect that the lens might be damaged, have it checked by your practitioner.
If a lens is dropped, do not move until you have looked carefully near where you stand. If a lens is wet it may adhere to hands, face, eye lashes, clothing or furniture. Do not overlook cuffs, pleats or shoes. A torch shone around at ground level will often locate a lens by reflections from the lens surface.
STORING AND CLEANING OF LENSES
Special soft lens solutions are available and provide lens sterilisation and cleaning. Strict adherence to the cleaning and storage regime, described at the delivery of your lenses, is necessary. Because soft lenses absorb water, they will also absorb any water-soluble chemicals or impurities, consequently, precautions against contaminations are even more important. Strict hygiene is essential. NEVER USE SALIVA OR TAP WATER.
ADAPTING TO CONTACT LENSES
Before contact lenses can be worn successfully, the eyes must become adapted to the presence of the lenses. The time required for adaptation varies between individuals and with the different types of lenses and it is important to be able to distinguish between "normal" adaptation problems and signs or symptoms that require you to seek advice from your practitioner.
You will be given a wearing schedule designed to allow sufficient time for the eyes to adapt to the presence of the lenses. The wearing schedules will vary depending on the type of lens and the needs of the patient. A typical program for flexible lenses is given below.
WEARING SCHEDULE SOFT LENSES
First day 6 hours
Increase per day 1.5 hrs
Max before first
aftercare visit 8-l2 hrs
Some patients may need a break during the day or the lenses may need cleaning during the day. NEVER WEAR YOUR LENSES OVERNIGHT UNLESS SO ADVISED and if you stop wearing lenses for any length of time you will have to re-adapt by wearing them again for a reduced time. Excessive wear during the initial period of adaptation results in the "over-wear syndrome" characterised by:
(i) Severe pain in the eyes at 3 to 4 o'clock in the morning.
(ii) Extreme sensitivity to light (photophobia)
(iii) Blurred vision, watery eyes
Although no permanent damage normally results and the symptoms fade over the next 24 hours, the experience is an extremely painful one.
During the first few days of the adaptation period, avoid the following if possible:
-Wearing lenses in overheated or smoky atmospheres, or whilst sitting over a heater or fire. Take advantage of the increased comfort to be experienced in dull conditions in the fresh air.
-Sudden movements of the eyes to extreme of gaze.
-Driving a car with bifocal CLs, especially at night until confidence is gained.
-Subconsciously rubbing or manipulating the lids.
-Prolonged close work
-Altering your normal blink rate.
NORMAL SYMPTOMS DURING ADAPTATION
-Blinking and watering of the eyes
-Dislike of bright lights or looking upwards
-Tension in the face or forehead
-Moments of blurred vision
-Temporary blurring of vision with spectacles after wearing contact lenses
-One lens behaving better than the other
-Reflections from lights
-Temporary doubling of vision
-Displacement of lenses on the eye
-Some inaccuracy in judgment of sizes and distances
ABNORMAL SYMPTOMS DURING ADAPTATION
Seek advice if you have any of the following signs or symptoms:
-Persistent redness of the eyes especially if it lasts overnight. A lens should never be inserted into a `red' eye as you may have a corneal abrasion that you cannot feel due to the "sensory" adaptation
-Soreness or discomfort (without the lenses in) that lasts until the next day
-If the lens is grossly uncomfortable you should remove it, clean it, and reinsert it. If it is still uncomfortable the lens should be removed and not worn until the advice of your practitioner has been sought.
-If you ever have severe pain or a very red eye advice should be sought immediately.
Every morning after you insert your contact lenses you should check the following three things:
(i) How they see – Vision should be clear for both eyes (check them separately). If not, check that the lenses are clean and that they were inserted into the correct eyes.
(ii) How they feel – The lenses should feel comfortable on your eyes
(iii) How they look – Your eyes should be essentially “white”. If your eyes turn red upon insertion, re-clean the lens. If the eye is still red and uncomfortable, remove the lens and consult your optometrist.
LENSES INSERTION AND REMOVAL OF CONTACT
Initially, you should insert and remove your lenses over a cloth or towel spread on the table. A mirror might be handy while learning techniques, but you should learn to do without it. If you fail in an attempt to insert a lens, the lens should be rinsed before trying again.
Place the lens on the index finger and retract the lower lid with the second finger. Look up, and place the lens onto the lower portion of the sclera. Remove the index finger and slowly release the lid. Close your eyes and lightly massage the lid to help centre the lens.
Retract the lower lid with the second finger and place the index fingertip on the lower edge of the lens. Slide the lens down onto the sclera. Gently pinch the lens lightly between the thumb and index finger. Roll the thumb and index finger together causing the lens to double, which allows air beneath the lens, and remove from the eye.
-- Bruce Macnaughton is based in Australia and writes about cheap contact lenses and contact lenses sold online in Australia