Saturday, 23 July 2011

The ABC of Contact Lens Use

Published in "Panorama"

The ABC of Contact Lens Use

Samir could not comprehend when his eye specialist strictly advised him against contact lens use for his short sight. The specialist maintained Samir was not a suitable candidate for using contacts after completing a thorough eye checkup. Yes, while 95% or more people who want to wear contact lens can do so without any problem, there are a small percentage of people for whom wearing contact lens is not suitable, says Dr. Azim Siraj, Specialist Eye Surgeon, Prime Medical Centre, Dubai.

In the first instance, the people who require any kind of lenses are the ones with refractive errors, explains Dr.Azim. “These are the individuals who have myopia or short sight, hypermetropia or long sight, astigmatism and those above 40 years who need near vision correction for presbyopia. Contact lens is one way of correcting these refractive errors and it may be the ideal way in most cases since it provides sharper vision than the conventional spectacles.”

Another category of contact lens wearers are those using it for cosmetic purposes, who may or may not have a problem with their vision, explains Dr.Azim. “These people simply want their eyes to look different and therefore use coloured contact lenses. These lenses can also be incorporated with power should the individuals have long or short sight. Alternatively, there are people who have a defect in their eye; for instance, a part of the eye may be turned white or a part of the iris may be missing. These people wear contact lens to look normal and also to cut the amount of unnecessary light that can go in and cause glare. A third group of contact lens wearers use Bandage Contact Lens if they’ve suffered an eye injury. These lenses keep working such that medicine to the eye will be delivered on a time-related basis.”

Do all categories of contact lens wearers use the same kind of lens or is there any difference in the texture of these lenses? Dr.Azim clarifies, “Contact lenses are basically available in three types: soft, semi-soft and hard, based on the degree of oxygen permeability they allow. The soft lens are the most oxygen-permeable ones, hard lens being the least permeable.”

Elaborating on the relative importance of these types, Dr.Azim continues, “It is mostly the soft lens that are in use today. But it is easier to maintain the hard lens and also chances of infection are less as compared to the soft lens. Hard lenses are easier to handle and can be used reasonably ruggedly unlike soft lens which require gentle use because their wear and tear is faster. However, soft lens are very comfortable to wear though the amount of crispness of vision is not as sharp as when using a semi-soft or hard lens. This is especially the case if the cornea is more deformed because the soft lens moulds itself to the irregularity of the cornea and hence the correction achieved is not to the extent as obtained with the semi-soft or hard lens.”

Contact lenses are also classified according to the time period for which they can be used continuously; these are daily, monthly or extended wear, accordingly. “You wear the daily-wear lens in the morning and throw them at night after using for say twelve hours. The weekly, monthly and yearly wear lenses are similarly used for about 12 hours in the day and the same lens used for a week, month or year and then replaced with new ones. In the case of Extended wear lens, I normally ask my patients to wear them for between 8-12 hours and them remove them so as to allow oxygen flow to the cornea. However, the number of hours you can continuously wear these lenses, depend on the occupation of the wearers also”, explains Dr.Azim.

Who are the people who can wear contact lenses?
“Theoretically, anyone can wear contact as in the case of the cosmetic lenses which are indicated for anybody. However, there are specific groups of people for whom contact are indicated,” explains Dr.Azim. “If the difference in power between the two eyes is more than 3-4 dioptres, contacts will provide greater clarity of vision than normal spectacles. Contacts are advised for those who are already having a high power. The whole world looks much smaller to them because of the shrinking images caused by the high power. By wearing contacts, these individuals get almost a near normal vision. Where they could otherwise not see details of small images clearly, they are able to see much clearer with contacts. A person wearing spectacles sees the world only through the frame. For example, if someone is having high power and there’s somebody walking from the side, he cannot see clearly. His vision is restricted to he two tunnels which he sees through the frame; smaller the frame, smaller the tunnel. With contact lens, you get an all round view, from practically every angle!”

Further elaborating on the advantages of contact lens, Dr.Azim explains, “They are recommended for people with high astigmatism. Again, for people who have irregularity in their cornea, contacts are advised. Because if the cornea is not smooth, if it is bumpy, the light rays will get scattered irregularly. By using contacts, the irregularity is neutralized into a uniform surface making for better quality of vision. Then there is a certain eye condition called Keratoconis where the eye is conical in shape. Special contact lens can be worn to compensate for this to make vision better. Bandage contact lens are good for patients who’ve had eye injury or have had certain procedures like laser done to their eyes. Contacts are advised for individuals participating in certain kinds of hazardous sports also. Finally, we cannot deny the cosmetic advantages accorded by contact lens.”

Having listed a number of instances where contacts are preferred, it is equally true that not everybody can wear contacts, affirms Dr.Azim. “In the first place it is absolutely important for individuals to have a complete eye checkup before they can be prescribed contact lens. We do not advise contact lenses for certain groups of people.

If the tear secretion is not adequate, individuals suffer from dry eye syndrome. If these cases are severe, we do not prescribe contacts because the irritation will be very severe and the contact lens will cause more harm than good.

The tear function has to be evaluated and we have to see if the lid has any infection or if the pores of the lids are not clean. In such cases, the infection can get into the contact lens and cause scars which can be disastrous. If there is any scarring in the lids, the contacts will be constantly disturbed. Hence they are not advised for these individuals.

We also look for any eyelashes which could be growing in or which can cause some irregularity. Further, we look for any eye allergies to which the individual could be prone because contact lens itself can provoke an allergy in some people.

We require to check out the cornea to see if it is healthy to withstand a contact lens. If there is any abnormal blood vessel going to the cornea, using contact lens, particularly the hard type, can worsen it.

The occupation of the wearer should be considered; contacts are not advised for people working in dust-ridden environments, for instance in cement, asbestos and such other industries.

Once prescribed contact lens, for whatever reason, its careful maintenance is imperative to avoid infections and complications therefrom, cautions Dr.Azim. “The basic rule is hygiene which include the following aspects:

Fingernails should be cut close to avoid injury to the lens.

Wash hands thoroughly with soap and water and wipe clean before handling the lens.

The case containing the lens should be given adequate importance and kept clean at all; times since this can be one of the worst sources of infection. It should be washed well with ordinary soap and water; the soap should not be smeared on the case; instead, make a froth on your hand and with it, clean the case. Allow the case to dry naturally. Then put the solution in it.

Ideally, the contact lens solution in the case should be changed everyday; if not, once in two days.

Whenever you remove the contact lens from its case, clean it by putting two drops of the solution.

Use only the company recommended solution. Do not use mineral, distilled or filtered water or any other solution since the contact lens solution contains a mild soap, bacterial-static agents and a preservative.

If you are traveling, keep the case with you and ideally travel with a bottle of the solution also. This should be particularly done meticulously if you are using soft lens since once out of the solution, this lens is dead; it is not meant to be kept anywhere except in its case when not on the eye!

Though switching one brand of solution for another might not cause much harm, it is betterto use the company recommended solution. But do not switch solution meant for one type of lens for another since different components go into the making of solutions for hard, soft and semi-soft lens.

Wear protective goggles, especially while traveling or being exposed to strong gush of wind.

Never sleep with the contact lens unless it is a special variety and the eye specialist himself allows you to sleep with them, even if the nap is a short one.

Don’t swim with your contact lens on even if you are wearing goggles. A soft lens is like a sponge, absorbing any liquid it comes into contact with, thus enhancing the scope of infection from the pool.

Whenever there is any kind of eye infection, don’t use your contact lens.

Don’t rub your eyes with the contacts on.

Close your eyes, place a clean kerchief on the closed lid when you cry so that the tears get absorbed by the kerchief because there is every chance of the lens floating with the tears.

Cosmetic contact lens wearers should not use liquid eye liners; it is better to use pencil eyeliners instead.

Apply eyeliners after putting the lens in your eyes and apply it outside the lash margin. Similarly, put eye shadows after wearing the contact lens and apply make up lightly so that it doesn’t fall into the eyes.

Having elaborated on the maintenance of contact lens, Dr. Azim highlights the need to remain alert to symptoms which should prompt contact lens wearers to visit their eye specialist. “While an annual visit for a routine check is a must, if you find something different one fine morning after wearing your contact lens, you must visit the doctor. For this could indicate a small tear in the lens which you will not be able to make out with your naked eye. If on wearing the contact lens you find some irritation, remove it, clean it and put it on. If the irritation continues, allow the lens to soak overnight in the solution and then wear it. If the gritty feeling still persists, seek the specialist to find out if the lens is defective.”

Alternatively, your eye may suddenly turn red when you wear the contact lens. You may assume that it is because of the solution. If it is due to the solution, the redness should last for a few seconds or a couple of minutes and then disappear. However, if the redness persists despite cleaning the lens and soaking it overnight in the solution, visit your doctor for this could indicate early infection.

Gritty feeling as of dust falling in the eyes, uncontrollable watering from the eyes when wearing the lens, inability to look at light having a glare which you otherwise tolerated, suddenly seeing a white spot in your cornea, should all alert you to visit your doctor.

A final word of caution by Dr.Azim: “I always advice my patients to have normal specs as a backup to be used when the contacts are removed after a day’s use. The lesser your eye is getting exposed to contacts, the better because you need to allow your eye to breathe naturally.”


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