TYPES OF Contact lenses
- Gas Permeable Rigid ( GP / RGP )
- Soft Contact lenses (including universal fit soft lenses
- Extended Wear and Special Contact Lenses
- ROSE K2 LENSES
- ORTHO-K Lenses
- Cosmetic Colored lenses
Which Contact Lens to Choose
Now even hard contact lenses - the standard of yesteryears are out of favour in most eye hospitals and have been replaced by the more advanced Rigid Gas Permeable (RGP) contact lenses and Soft contact lenses. These two types of lenses now have innumerable subtypes of materials and more are being added every year. There is as yet no lens material which can be called a universal ideal and each patient needs to be assessed on an individual basis.
1. Gas Permeable Rigid ( GP / RGP or at times called Semi Soft ) Contact lenses
These are essentially hard contact lenses which allow gases (oxygen) to diffuse through to the eye while retaining most other advantages of earlier hard contact lenses viz. the ease of maintenance & somewhat lesser risk of infection. They provide sharp vision even for eyes with cylindrical number and being hardier usually last longer.
These are good lenses for patients of irregular astigmatism eg. after corneal injury and Keratoconus. Special Scleral, Rose-K 2 & Boston lenses are also available.
The disadvantages are that these are relatively more difficult to fit. May occasionally displace to a side and at times cause irritation or watering from the eyes and hence may not be tolerated by all patients.
2. Soft Contact lenses (including universal fit soft lenses which are wrongly called Super-soft)
- are generally well tolerated by most people.
- Do not displace easily even in active sports and are easier to fit.
- These lenses are also oxygen permeable being composed of a spongy plastic which contains up to 40% or even more of water.
- These however need somewhat more care and maintenance in order to avoid infection and collection of protein /salt deposits from tears. Lens deposits can cause eye allergies and also limit lens life. Good lens care & hygiene with better lens care solutions have made soft contact lens infection less common.
Disposable soft contact lenses are now available which are less likely to cause infection and allergies. These can be monthly, fortnightly or daily disposables.
Torics for cylinder number, Semi-Scleral soft lenses and piggy-back contact lenses are also used for irregular numbers.
3. Extended Wear and Special Contact Lenses
Though most of the patients use contact lenses as a substitute for glasses, contact lenses have a number of other uses also like cosmetic masking of disfigured eyes, changing the colour of the eyes and balancing vision between two eyes with very different numbers. Numerous colours like blue, green, hazel etc are available in either single or mixed shades and with or without correcting number.
Extended wear contact lenses of both GP or Soft type are available which can even be worn while sleeping. Extended wear contact lenses should be used only by those patients who have a compelling occupational reason, medical problem or a physical disability which limits daily lens care, since these lenses are more prone to infection and other problems.
4. ROSE K2 LENSES
Specially designed rigid lenses to correct the high astigmatism in IRREGULAR CORNEA or KERATOCONUS .These lenses are customized, multicurved made according to corneal shape .
5. ORTHO-K Lenses
Ortho-K contact lenses (Overnight Vision Correction, Corneal Refractive Therapy and CRT), are special rigid gas permeable contact lenses that temporarily reshape the cornea to reduce refractive errors such as myopia, farsightedness and astigmatism, so that during waking time the vision stays corrected without glasses or contact lenses.
The US FDA overnight orthokeratology is approved up to -6.00 diopters of myopia and a maximum of 1.75 diopters of astigmatism.
Contra-indications may include
- Inflammations or infection of the anterior segment of the eye or the cornea
- Disease, injury or abnormality affecting the cornea, conjunctiva or eyelid, or impacting contact lens wear
- Very dry eyes or low eye moisture, Corneal hypoesthesia (low sensitivity)
- Eye related allergies, including allergies to contact lens solutions
Lens Care for Healthy Eyes
By design, contact lenses are foreign objects requiring finger touching to insert in the eye. This introduces a possibility of infection. Contact lens care must be followed meticulously to avoid contact lens associated problems. Cleaning of contact lenses removes all the contaminants that collect on your lenses. Proteins, calcium, lipids from tears and lids form deposits on lenses. Disinfection kills all harmful bacteria and germs that infect the lens material so disinfection must be carried out every night on lens removal.
- Multi-purpose solutions are used for cleaning, rinsing, disinfecting and storing your contact lens, all with the same solution
- Always wash and dry your hands properly before touching your contact lenses
- Remove the lens and rub in the palm of your hand with few drops of multi-purpose solution. Manual rubbing and rinsing the lens is very important.
- Place the lens in the clean lens case and fill with fresh multi-purpose solution.
- Always rinse your storage case after use with freshly boiled and cooled water or sterile saline solution and allow to air dry at least once a week.
- Change your lens storage case at least every 3 months –monthly is preferable.
- Old solutions , opened solutions should be discarded after 30 to 90 days as per manufacturer instructions.
- Apply eye makeup after inserting your lenses and same way at night remove lenses first before attempting to clean / wash off the make-up. Eye cosmetics used should be water soluble so that they do not permanently discolour your lenses.
- In the case of any redness, pain or discharge from eyes discontinue the contact lens wear and consult your doctor immediately.
Patients are instructed always to wash both hands and face before putting contact lenses in the eye. Use a good quality soap but avoid cream soaps just before contact lens handling.
- Keep your ﬁnger nails cut
- If you drop a lens do not rub with the surface, pick it up letting it stick to a wet ﬁnger.
- Use water based cosmetic only.
- Keep the contact lens case handy while going out so to be able to remove contact lenses in case of an emergency like getting some insect or dust in the eye.
- Use proper and fresh lens cleaning and storage solutions and give equal attention to hygiene of the contact lens storage case.
- Report immediately to the doctor in case of red eyes or blurred vision not correcting itself in a short while.
- One should not sleep with the lenses in the eye.
- Patients are also instructed not to use any eye drops unless prescribed by an eye specialist.
- Not to exceed the advised wearing time.
- Not to wear a broken or chipped lens and to discontinue lens use in this case
- Avoid use of cold cream, lotion, or oily cosmetics just before handling your lenses,
- Do not rub your eyes while wearing contact lenses.
- Do not use lenses if redness, pain or blurring persists. .
- Do not engage in sports with your lenses on until you are well adapted to wearing them.
- Do not swim with your lenses on.
- Do not share your contact lenses with anyone, this can result in infection in your eyes.
- Do not put contact lens solution directly into your eyes.
- Never use water direct from the tap to rinse your lenses or storage case. Water from roof top storage tanks is almost always infected.
Though Laser Correction for weak eye sight is the most preferred modality of getting rid of glasses, many patients for various reasons like apprehension of laser, being under age for laser correction or some other medical reason use contact lenses as a substitute for glasses. It has been documented that Vision loss associated with contact lenses poses a greater risk than laser eye surgery according to various research studies. The risk of vision loss was highest in patient who wore extended wear contact lenses (slept with their contact lenses). Contact Lens patients are more prone to eye allergies, eye infections including corneal ulcers which may even lead to drop in vision.
Thanks to technology advances—such as faster lasers, advanced laser eye treatment techniques, more skilled surgeons, better patient screening and a number of related improvements—laser eye surgery is becoming more and more precise besides being even more safe today. Our laser system will automatically stop laser firing with microsecond response time in case of any error or more than trackable eye movement by patient.
Myths and Misconceptions
The reduction of number by use of contact lenses (Orthokeratology) is possible in a limited number of patients but since is almost impossible to predict beforehand as to who will benefit from this; it should normally not be the only reason to go in for 'Contacts'.
Another frequent misconception is that a displaced contact lens can get lost inside the eye. This is almost next to impossible except in cases of severe perforating eye injury. In most circumstances contact lenses may in fact save the eye from minor injury by acting as a cover on the eye.
Though Lasers & Refractive Corneal Surgery (Myopia Surgery. Astigmatic or Hyperopia Surgery. Excimer Laser. Bladeless LASIK, Multifocal LASIK, ASA etc.) have coming up well as yet another alternative to glasses, contact lenses will continue to shine like a jewel in the eye.
This information is for general guidance only, please ask your eye specialist about specific advice in your case.
Inhouse Optical Store
All kinds of branded and non-branded frames, good quality lenses, sunglasses, contact lenses, contact lenses cleaning solutions and other eye wear are available inhouse at a reasonable price