What is Contact Lens?
A contact lens is an artificial lens placed on the cornea for refractive, treatment or diagnostic purposes. The most common indication for wearing contact lenses is for correcting refractive power. Earlier, people used to wear contact lenses only for correcting myopia (nearsightedness) and hypermetropia (farsightedness), but now special lenses are available for use in astigmatism (called toric lenses), and for presbyopia as well.
There are many types of contact lenses in use today. The two most important types are the soft, and rigid gas permeable lenses, depending upon the hardness of the lens. Soft lenses are very comfortable and are more popular for routine refractive correction. Soft lenses made of silicone hydrogel are more comfortable to wear than lenses made of other materials.
However, rigid lenses have their own benefits and are preferable in specific conditions like keratoconus and certain types of astigmatism. Even presbyopes may use contact lenses if they do not wish to wear glasses for reading.
They can also be used for special occasions such as weddings, travel and even during swimming.
Soft contact lenses are available in a wide variety of materials, and are available as regular daily wear lenses (which have to be changed annually), or as disposable contact lenses with variable time periods in which to change, such as disposable quarterly (have to be changed every 3 months), monthly, bimonthly and daily disposables. Daily disposables are particularly useful in that no lens care regimen is required. They can be removed from the packing and placed directly in the eye, and thrown away at the end of the day. The risk of complications such as infections and contact lens discomfort is much less with these lenses. However, the cost can be prohibitive for regular use. They can be also used for special occasions such as weddings,travel and even during swimming.
Contact Lens for Cosmetic use - Soft lenses are also available for cosmetic use (colored contacts); in other words, they may or may not have any power in them, and are worn so as to change the color of the eyes while being worn.
Discomfort with Contact Lens - While contact lenses are very useful for those who do not wish to wear glasses, it must be remembered that sometimes people may experience contact lens discomfort. This may be due to a variety of reasons; the most common among these as described by the TFOS (Tear Film And Ocular Surface Society) after conducting an international workshop on contact lens discomfort were –
- Meibomian gland dysfunction (meibomian glands are the glands in the eyelids that produce the superficial fat layer of the tear film) and lid wiper epitheliopathy (due to the action of the eyelid as it sweeps across the lens surface). These can lead to dry eyes that manifest as symptoms of blurriness, irritation, dryness, burning and itching.
- Dry eye disease may be pre-existing, and symptoms may be precipitated or exacerbated by the use of contact lenses. Patients with mild to moderate dry eyes may be treated by ocular lubricants. Patients with more severe dry eye may need to temporarily suspend wearing contact lenses till treatment results in improvement of their symptoms.
- The most dangerous complication of wearing contact lenses is infection. Contact lenses wearers are more susceptible for eye infections as compared to those who do not wear them. Rigorous and meticulous care can grossly reduce this susceptibility.
There are certain ground rules for contact lens wear that all wearers must follow. Please follow the tips enumerated below to be safe.
1. Follow your doctor’s instructions meticulously. Every instruction given by your doctor has a purpose; most ocular problems arising as a result of contact lens use do so because of a lack of compliance on the part of the contact lens wearer. If you do not understand or comprehend the significance of the instructions, DO NOT HESITATE to clarify the same with your eye doctor. Do not take instructions from the opticians who dispense contact lenses.
2. Maintain meticulous hygiene when handling your contact lenses. Wash your hands with soap (that does not contain a moisturiser, lanolin or perfume) and clean under running water. Dry your hands with a lint free towel before touching your lenses. DO NOT TOUCH YOUR LENSES WITH WET HANDS.
3. Clean your lenses only with the contact lens solution recommended by your doctor. Rub, rinse and soak your lenses in the storage case in fresh solution after removal, and rub and rinse your lenses before putting them on again. You MUST rub your lenses even if you are using a “NO RUB” solution. You must spend a minimum of one to two minutes cleaning your lenses. Storage in the case should be for a minimum of 4-6 hours. The contact lens solution must be used within 3 months of opening the bottle, to reduce the incidence of contamination; any unused solution after that must be discarded.
4. Inspect your lenses just before you put them in your eyes every day. Place the contact lens on your index finger and look for deposits, dust particles and particulate matter. DO NOT wear torn or damaged lenses. Also make sure your lens is not inside out. To do this, observe the lens as it rests on your finger. If the edge is turned out forming a kind of ledge, the lens is inside out. If it is curved inwards (and looks like a bowl), then it is fine.
5. Report to your doctor if you notice any redness, irritation, diminution of vision, discharge, excess watering or sensitivity to light. These symptoms may be the harbinger of severe problems that may lead to vision loss.
6. Wear your lenses only for the recommended duration, and change to a fresh set of lenses after the recommended time period. For example, if you are using monthly contact lenses, change to a new pair after one month. Do not extend the period of use. Failure to replace the lenses on time can lead to toxicity and infections.
7. Take proper care of your storage case. When you put on your lenses, throw away the old solution, rinse with fresh solution and then air dry the case upside down on a clean lint free towel or napkin. Fill the case with fresh solution just before removal of your lenses. Be generous with the solution; the contact lenses should be submerged in it. Wash the case with soap (using a clean brush) and warm water once a week and air dry. The storage case should be replaced with a new one every 3 months. If you have not used your contact lens for 3 or more days, throw away the solution and disinfect the lenses afresh. Always have a pair of the latest prescription spectacles as a backup. You may need them if you encounter any problem with your contact lenses.
8. If you have mild dry eye symptoms, you can instil an ocular lubricant that has been recommended by your eye doctor just before insertion of your lenses. You may also use lubricants on top of your lenses throughout the day as needed. Check with your doctor to make sure you are using lubricants that are compatible with contact lens wear.
9. Be judicious in your use of face and eye makeup. Put on makeup (only hypoallergenic products) after inserting lenses and remove your lenses before removing makeup. Only water based makeup should be used. Kajal should not be used, and eyeliner should not be applied between the eyelashes and the lid margin. Hairsprays should be applied before inserting contact lenses.
10. Always remove your contact lenses before going to sleep, unless you are wearing extended wear lenses and your doctor has permitted you to wear them continuously. Sleeping in your lenses results in less oxygen reaching your cornea and can result in corneal infiltrates and can predispose to infection, which in turn can result in blindness.
Contact Lens - Top 15 Do’s and Don'ts
1. DO NOT use tap water to clean your lenses or to place in your storage case. Using tap water is a very common cause for development of sight threatening infections of the eye, especially an infection called acanthameba keratitis. Even distilled water is not safe. Uncontrolled acanthameba keratitis may necessitate a corneal transplant, or in very severe cases, removal of the eye.
2. DO NOT also use saliva to wet your fingers or your lenses.
3. DO NOT share your contact lenses with your friends. Microorganisms can be transferred from one person’s eyes to another person’s this way.
4. DO NOT swim with your contact lenses on. If you want to swim with contact lenses wear the daily disposable lenses, which should be discarded immediately after the swim. If you do not discard the lens you should not let your eyes come in contact with any kind of water such as in showers, swimming pools, hot tubs, canals, lakes or rivers. Chlorinated pools do not protect against eye infections. However, if you must wear your lenses in a swimming pool, use water proof goggles, remove your lenses immediately after coming out, and disinfect your lenses in the usual way. Discard the lenses if they have come in contact with the water. Have a pair of backup spectacles or contact lenses since you cannot immediately wear the pair with which you have swum. Lack of the above precautions can predispose to sight threatening acanthameba keratitis.
5. DO NOT top off the solution in the storage case; always throw away old solution and rinse the case with fresh solution.
6. DO wear sunglasses when going out in the sun. Contact lenses do not protect against ultraviolet or infrared rays.
7. DO NOT store lens cases and solutions in the bathroom, as there is a high risk of fecal organism contamination.
8. DO NOT buy colored contacts (contact lens used for changing eye color) from any place that is not recommended by your eye doctor. These lenses are available for purchase by unauthorized personnel without medical supervision. They can be dangerous to your eyes. Even cosmetic contact lenses require a prescription by an eye doctor.
9. DO keep your nails trimmed and filed smooth, as finger nails can damage contact lenses as well as injure the cornea.
10. DO always wear the right lens first, so as to avoid mix-up of the lens powers of the two eyes.
11. DO make sure that each time you clean your lenses; you have the following ready before you start – lint free towels, contact lens cleaning solution, lens case and a mirror.
12. DO have a trial fitting of the lenses for the first time in your doctor’s clinic, so that you can be sure you are doing it right. You can also clarify any doubts that arise during this time.
13. DO ALWAYS have a new contact lens solution before the previous one gets over.
14. DO NOT change the brand of solution without consulting your doctor.
15. DO always have the fact that you are wearing contact lenses on your record. There have been instances of people having lost vision because of non-removal of contact lenses after falling unconscious.
16. DO NOT rub your eyes with your contact lenses on. Doing so can cause minor abrasions in your cornea, which are then susceptible to infection from the microorganisms which may be present normally in your eye.
Help in Early identification of Diabetic Retinopathy
- Contact Lens Wearer Demographics and Risk Behaviors for Contact Lens-Related Eye Infections - United States, 2014 - (https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6432a2.htm)
- Nichols JJ, Willcox MDP, Bron AJ, et al. The TFOS International Workshop on Contact Lens Discomfort: Executive Summary. Invest Ophthalmol Vis Sci. 2013;54:TFOS7–TFOS13.
- Nathan E. Contact lens practice.3rd edition. Elsevier;2017.
- Abdelkader A. Cosmetic Soft Contact Lens Associated Ulcerative Keratitis in Southern Saudi Arabia. Middle East African Journal of Ophthalmology. 2014;21(3):232-235.
- Paulo R. B. Fernandes, Helena I. F. Neves, Daniela P. Lopes-Ferreira, Jorge M. M. Jorge, José M. González-Meijome. Adaptation to multifocal and monovision contact lens correction. Optom Vis Sci. 2013 Mar; 90(3): 228–235.
Latest Publications and Research on Top 10 Tips for Contact Lens WearersControlled In Vitro Delivery of Voriconazole and Diclofenac to the Cornea using Contact Lenses for the Treatment of Acanthamoeba Keratitis. - Published by PubMed
Novel polyvinyl pyrrolidone loaded olopatadine HCl laden doughnut contact lens to treat allergic conjunctivitis. - Published by PubMed
A Study of the Evaporation of Hexane Lenses on an Ionic Liquid Surface: Effect of Wetting Mode. - Published by PubMed
Cytosine-functionalized bioinspired hydrogels for ocular delivery of antioxidant transferulic acid. - Published by PubMed
A computational analysis of retinal image quality in eyes with keratoconus. - Published by PubMed