Lens Clinic

 

Contact lenses are categorized by their materials, wear and replacement schedules, how long before a lens needs to be discarded. All contact lenses are made from different types of plastic and are classified into two main groups of soft and hard lenses.

It should be explained that contact lenses are not always worn for improvement of vision problems, they can be worn as cosmetic devices or in some cases they are prescribed by ophthalmologists to wear along with glasses when a patient's vision is not completely corrected with glasses. And even some babies with congenital cataract should wear contact lenses until they are old enough to have intraocular lenses.

 

 Soft lenses are made of Sillicon Hydrogel. Soft silicone hydrogel lens may have no optical power and be used as a bandage after corneal refractive surgery for corneal ulcers or may have optical power and be an alternative to glasses to correct refractive errors. Soft lenses replacement schedule can be on a weekly, daily, or monthly and yearly basis.

Soft lenses have 52 to 57 percent water. They are quite comfortable and you can get used to them very soon. These lenses cover the entire surface of the cornea and are made of flexible and water-absorbing materials, which is why they form the cornea after you put them in your eyes and usually do not irritate the eye as an foreign body in the eye. Soft lenses are more expensive than hard lenses and require careful and consistent hygiene compliance. These lenses become corrosive in contact with smoke, vapor, aerosol sprays, and cosmetics.

How to Put in Soft Contact Lenses:

• First, wash your hands with soap.

• Dry your hands carefully with a lint free towel.

• Always keep remember that before handling your contact lens, prepare your lens solution, lens case, and cleaning serum, even open the lens case lid and then wash your hands before inserting your lenses.

• Check that the lens isn't inside out. The curve side of soft contact lenses should be perfectly concave.

• Making sure the contact lens forms a perfect bowl shape with the edges appearing straight and the digits aren’t backwards. If the edges look flared out the lens is inside out.

• Do not worry if you put your contact lens on inside out. It will not harm your eye. It will only move too much when you blink and cause blurred vision.

One-Hand Placement Technique:

• Use a concave magnifying mirror to insert your contact lenses

• Place the lens on tip of your index finger.

• With your head up, looking straight ahead, pull down your lower eyelid with the middle finger of your placement hand

• Look up steadily at a point above you. Then place the lens on the lower white part of your eye.

• Look down to position the lens properly. Remove your index finger and slowly release the lower lid. Close your eyes for a moment: the lens will center itself on your eye.

• If you can not insert your lens after your second attempt, make sure to rinse off your lens with a 0.9% sodium chloride solution to prevent your lens dryness, and then try again.

• If your lens drops on the floor, be sure to rinse it with a sterile lens cleaning solution and finally rinse with a lens cleaning serum then try again.

 

Safety Tips:

• At first when you start wearing soft contact lenses you may be able to wear them only for a short time, but after this initial adaptation period, you can wear them for longer periods of time. At this time, you should have a suitable lens preservative solution for storing your lenses.

• Remove your contact lenses before going to swim, sleep or taking a shower.

• Put your contact lenses on before applying make up and take your contact lenses out if you want to remove your eye make up.

• Avoid all harmful or irritating vapors and aerosol sprays such as hair sprays while wearing your contacts.

 

 Hard lenses are also known as Rigid Gas Permeable (RGP). Soft contact lenses are not successful in patients with high astigmatism. Hard contact lenses only cover part of the cornea surface and are rigid, not flexible. Perhaps the reason that people are less likely to use hard contact lenses is that they get used to hard contact lenses after longer periods of time.

On the other hand, these lenses can be used for a longer period of time, they are less likely to get dust and attract and breed bacteria and can be cleaned easier compared to soft lenses. Ophthalmologists usually recommend hard lenses to those who are looking for higher quality vision.

The most important problem with hard lenses is that you have to wear them regularly until you get used to it, but for soft lenses, even if you don't wear your soft lenses for a week, they'll still be comfortable when you put them on a week later.

Since about 1981, Oxygen transmission contact lenses have entered the market, which even provide the necessary oxygen for the cornea during the night (roughly six times higher than previous ones). The lens oxygen permeability is indicated with the abbreviation of DK which is a certain number for each lens and should be greater than 120 DK for wearing overnight (although they are not recommended because of the risk of eye infection).

Some RGP lenses that are most commonly used in infants and children after cataract surgery and corneal astigmatism, which may develop after an eye injury or eye surgery, and are prescribed for overnight wearing, can be used up to 30 days . Orthokeratology lenses are a type of hard lenses which are only used overnight during sleeping. Today they are rarely used t due to a higher risk of infections and corneal scratches and ulcers, and are not recommended.

Advantages of Hard Lenses:

 First, because hard lenses are made from a firm plastic material, they retain their shape when you blink, which tends to provide sharper vision than pliable soft lenses. Second, hard lenses also are extremely durable. Although you can break them (for instance, if you step on them), you can't tear them easily, like soft lenses, and the protein and fat of tears will not be attached to them.

In fact hard lenses are the best choice for some people for whom soft contacts don't produce the desired visual acuity and they want to have sharper vision, or for people with astigmatism which their astigmatism can not corrected by soft contact lenses. Hard lenses also are suitable for the treatment of corneal keratoconus and presbyopia correction. Recent studies have shown that in children with myopia (nearsightedness) wearing hard lenses can slow down the progression of myopia.

Recommendation:

 Make sure to purchase your contact lenses from a trusted ophthalmic center and Take advantage of the experts’ advice of the optical shop on choosing the right contact lenses. Never purchase your contact lenses from an optical shop of another medical center or office different from where your ophthalmologist examined your eyes and prescribed contact lenses for you, because the examiner is responsible for your examination and should be answerable to you.

 

How to Deal With Hard Contact Lenses:

• It is better to do this on a clean and smooth surface so that your lens can easily be found on the finger if it drops.

• Try to use a concave magnifying mirror to insert and remove your contact lenses.

• First, rinse your hands thoroughly with soap.

• Dry your hands carefully with a lint free towel.

• If you want to put the lens in your right eye, first bend the head slightly. Open your eyes completely. With your left hand, hold the upper eyelashes of the right eye upward, and place the lens on the right hand index finger, and pull your lower eyelid down with your middle finger of your right hand and slowly move your index finger toward your eye, while focusing on your finger steadily, place the lens on the cornea.

• The lens should be placed in the center of the cornea. If the lens does not settle onto your eye properly, you should move it toward the center of your cornea with your finger or the edges of your eye lid.

• Look at the mirror; see where the lens is located. Look at the opposite side of its location, and then move the lens with the edges of your eyelid toward the center of your cornea. If you are not able to do this, remove the lens and put it in your eye again.

 

How to Take Out Hard Contact Lenses:

First, wash your hands and then dry them thoroughly. Make sure that the lens settles properly onto the center of your cornea and then remove it with one of the two following methods:

1- Open your eyes as wide as possible so that your upper eyelid is placed on the white of your eye. Place one of your fingers at the outer corner of the eye and gently pull it to the corner at the same time slowly. Once you blink, the lens will fall out into your other hand.

2- In this method, you use your middle fingers of your both hands to hold your eyelids open. The fingers should be as close as possible to the edges of the eyelashes and then push your eyelids toward the center of your eye so that the edge of your lower eyelid goes under the lens and causes it to fall out.

 

Wearing Schedule for Hard Contact Lenses:

Wear your contact lenses for 2 hours per day of the first week and then increase 1 hour per day of each week until in the seventh week you can wear your contact lenses for 8 hours per day comfortably.

 

Care Instructions for Hard Contact Lenses:

• Remove your contact lenses from your eyes at night and after rinsing them with tape water and cleaning serum or 9% Sodium Chloride solution, leave them in a sterile soaking solution until morning. When rinsing your contact lenses with tap water, it is best to put a plastic basket below the tap so that if you happen to drop them, they will fall in the basket and not be lost. In the morning rinse them again with tap water before putting them in your eyes.

• For more information bout how to use a cleaning or soaking solution or the best brands of these solution, ask the eye care professionals in the lens clinic who are responsible for providing patients with more information.

• Always remove your lenses from your eyes before going to bed, taking a shower or doing aerobic exercises.

• Finally, if you can not do this yourself, be sure to be referred to the lens clinic of Noor Eye Hospital.

 

Hybrid lenses, which are a combination of soft and hard lens materials, are an excellent choice for people with keratoconus who can not tolerate ordinary hard contact lenses, or those who do not have sharp vision even with wearing hard contact lenses.

 

Colored lenses, although may be considered as aesthetic and cosmetic devices from a consumer's perspective, but it should be noted that they are medical devices and, like all medicine devices, they have also some complications. All ophthalmologists are fully aware of the complications of these lenses and when prescribing colored lenses, inform people about their complications. They provide individuals with more information about, how to put in and take out contact lenses, wearing and replacement schedules and complications of colored contact lenses.

Colored lenses have 5 main colors: brown, blue, green, gray and purple, and a wide range of colors between these main colors.

Before using a color lens, even if your vision is not poor, you should be referred to the lens clinic. The cornea is a dimension that may vary from person to person. Each lens also has altering parameters that show that the lens only fit on some eyes, not all of them. Therefore, a lens that is fit on a person's eye may be too small or too big for another person, which multiplies the risk of lens complications.

A hairdresser or a person who works in a pharmacy has not enough knowledge about contact lenses, and do not qualify to prescribe suitable contact lenses for you.

Make sure you always buy your contact lenses from a reputable source because some colored contact lenses are not standard and sometimes the colored and chemical materials used in them and their incompatibility with the tissue of the cornea cause eye infection and ultimately the spread of infection to other tissues of the eye and blindness of the person.

 

These types of lenses are used to correct extreme irregularities of the cornea and highly advanced keratoconus.

 

PROSE is a lens-like prosthesis that is used to treat extreme corneal irregularities, severe eye dryness, chronic inflammation of the surface of the eyeball, and severe edema of the eyelid and conjunctiva.

 

It should be said that:

• Soft contact lenses that are used to correct refractive errors because they are directly placed on the cornea provide a wider field of view for you.

• Contact lenses do not have some disadvantages of glasses, such as the weight of glasses and appearance problems (Some people don't like how they look in glasses )

• Contact lenses typically aren't affected by weather conditions and won't fog up in cold weather like glasses.

• Soft contact lenses can correct all refractive errors, such as myopia, hyperopia, astigmatism, presbyopia and etc.

• Colored contact lenses allow you to change the color of the eye and also improve your vision.