Contact Lenses


One of the common methods for the correction of refractive errors is the use of contact lenses. By using contact lenses, it looks like you wear no eyeglasses and at the same time you can experience better vision. It should not be forgotten that improper use of contact lenses can lead to problems such as corneal infections, which in some cases will be very severe and will result in partial loss of vision. This guide will help you properly wear and care for your contact lens. A special clinic for contact lenses has been established in Iran-Tehran Noor Eye Hospital .

Contact lenses are divided into the following two types:

- Soft contact lenses

- Hard contact lenses

Definition of soft contact lens

The soft contact lens is made of flexible polymers and is designed to fit easily into the cornea and allows oxygen to pass through its molecules to prevent corneal oxygen deficiency. Soft lenses have 25 to 79% water, they are quite comfortable and the user gets used to them very quickly.

Definition of hard contact lens

These lenses are made of polymers with permeability to oxygen. Hard lenses also cover the corneal astigmatism; while for those who have irregular corneas, such as those with keratoconus, hard contact lenses offer good quality of vision, much better than glasses.

Recent advancements in contact lenses have led to the introduction of a new generation of contact lenses. These lenses are made in monthly disposable, multifocal, toric, and UV contact lenses. There are also other contact lenses that change the shape of the cornea and correct the person’s vision without surgery, which are called orthokratology or CRT. Usually, this type of contact lenses is used overnight; during this time, the shape of the cornea is changed, and the person’s vision will improve throughout the day without using contact lenses.

Colored Contact Lenses

At Tehran Noor Eye Hospitalcolored contact lenses are divided into the following groups:

- Visibility tinted lenses

- Color enhancement contact lenses

- Opaque contact lenses

- Light-filtering contact lenses

Colored lenses can only be cosmetically applied, as well as to correct astigmatism, presbyopia or refractive errors.

Visibility Tinted Lenses

A light blue or green color is added to the contact lenses to be detected when the lenses are inserted or removed or when they fall to the ground. Because the color is very light, it does not affect the natural color of the eye.

Color Enhancement Contact Lenses

The transparent lenses are darker than the visibility tinted lenses and intensify your natural eye color. This type of lenses is more suitable for people who have bright eyes and want to sharpen their eyes.

Opaque Contact Lenses

Colors of these lenses, which include a wide range of colors, change significantly the natural color of the eye. Companies that make tinted contact lenses do their best to make these lenses look like irises, even creating a series of colored lines and shapes on the lenses to make them look more natural. The center of these contact lenses, which is the pupil's location, is transparent so you can look beyond it.

Light-Filtering Contact Lenses

These lenses are newly manufactured and are mostly used in sports fields to exacerbate certain colors, for example, the yellow filter makes tennis or golf balls more specific in the field and easier to target.


Continuous Wear Contact Lenses

Continuous contact lenses are lenses that can be used at bedtime. Some of these contact lenses are only usable daily and should be taken at bedtime. Continuous lenses bring more oxygen to the cornea, most of them can be used for up to 7 days and discarded after 7 days.

There are two types of contact lenses that can last for up to 30 days: CIBA night and day contact lenses and Bausch and Lomb pure vision contact lenses. However, the contact lenses that are worn overnight increase the risk of eye infection than daily contact lenses, because dangerous organisms that enter the eyes through the fingers, eyelids, or lens solutions come under contact lenses and grow better overnight and increase the risk of corneal infection. Of course, because 30-day or 7-day interchangeable contact lenses do not require contact lens solutions, they reduce the amount of microorganisms that enter the eye and don't increase the risk of infection. 30-day contact lenses, that are now available, are made of highly penetrating oxygen-permeable silicon hydrogels.

For example, the "night and day" lenses allow 6 times more oxygen to pass through the lens to the cornea than regular contact lenses. It has been shown that smoking is an important risk factor for continuous wear contact lenses complications.

To reduce the risk of corneal infection through continuous contact lenses, the lenses can not always be worn. For example remove the lenses before sleeping and only sleep with them when you are napping during the day or when you are on vacation and you have to sleep while you wear contact lenses. Of course in this situation the risk of using the lens solution and lens case is added.

Be sure to remove the lenses quickly and contact your ophthalmologist immediately when you feel uncomfortable or burned or discolored.

-Rigid Gas Permeable Lenses (RGP)

Rigid contact lenses, that are oxygen permeability, are different from the old- fashioned hard lenses of previous decades. Hard contact lenses were initially made of PMMA, causing discomfort when used because they were not permeable to oxygen. Gas permeable lenses became available and common in the mid-1980s. Rigid gas permeable lenses made of silicone-containing compounds are more flexible than PMMA and transmit more oxygen to the cornea, even more than do traditional soft contact lenses.

- Gas Permeable Lenses (GP)

GP lenses provide sharper vision, last longer, are more resistance to sediments, easier to clean, and because of their longer durability, they are cheaper than lenses than soft lenses. But it should be said that soft lenses are more comfortable than gas permeable lenses which need to get used to them.

 • No change in appearance and beauty

 • More freedom in sports and other physical activities

 • Allow a natural field of view than eyeglasses

• The need for health care

• The need for careful maintenance in order to prevent its loss

• Difficulty in prescribing to patients with dry eye

• Problems in prescribing to people with high degrees of astigmatism

• High risk of infection in the eye

• Restrictions on use in some environments, jobs and water sports

• The need for frequent replacement due to short life span

• contact lens intolerance in some people over time

The order of the steps described the use of soft contact lenses in Tehran-Iran Noor Eye Hospital to contact lenses wearers is as follows:

1. Wash and rinse your hands properly.

2. Remove the lens from the lens case and disinfect it.

3. Put the lenses on your eyes.

4. Disinfect the contact lens case and dry it.

5. Removing the lens from the eyes.


How to Wash Your Hands

Before placing the lens on your eyes or before removing it from your eyes, wash your hands properly with soap and water. It is best to let your hands dry out or use a clean, dry napkin to dry them. Remember that lints of soft tissues and cloth hand towels may fall behind the contact lenses and cause eye irritation.


Remove Your Contact Lens from Your Contact Lens Case and Disinfect It

The most important step in preventing eye infections is disinfecting your lenses each time before you put them in your eyes. Today, multi-purpose solutions are often used. These solutions have antiseptic, moisturizing and cleaning properties and are also usable for rinsing. In this section, first shake the contact lens case with the lid closed slightly so that the lens is removed from the wall of it and allow it to easily be ejected. Then place the right eye contact lens in the palm of your left hand and pour a few drops of the wash solution on it and rub it with the soft part of the right finger for 10 seconds. Now rinse with a few drops of rinse solution.


Put Your Contact Lens on Your Eye (Your Right Eye)

Place the lens on the tip of the index finger or the center of your right hand, which is almost dry. With the fourth and fifth fingers of your right hand, pull your lower eyelid down and place the lens gently on the eye. Leave the lower eyelid first, then release the upper eyelid and slowly move the eyelids. We recommend doing this in front of the mirror in the first days. To prevent mistakes, first open the right lid of the lens case and then left one.

Note: You can apply these same recommendations for placing the lens on the left eye too.


Disinfect Your Contact Lens Case and Dry It

Studies have shown that 80% of the lens of lens users who use contact lenses contains dangerous bacteria that can lead to corneal infection. Then make sure that your contact lens is completely clean. To do this, after placing both lenses on the eyes, fill the lens with a lens wash solution and rub it with your index finger, the floor and the walls of it, to remove the bacteria and protein substances sticking to the walls. Then rinse it again with the solution and open the lids for 30 minutes to allow it to dry, and then close the lids.

*Make sure not to dry your contact lens case in a toilet or bathroom.

The ophthalmologists of Tehran-Iran Noor Eye Hospital provide the patients with necessary guidelines about how to use contact lenses.


How to Remove Your Contact Lens from Your Right Eye

To do this, first wash, rinse and dry your hands well with soap and water. Then look up and pull down your lower eyelid with your middle finger. Using your index finger and with the softness of your finger slide the lens down to the white of your eye. Pinch the lens between your thumb and pointed fingers and remove it from your eye. As we advised, it is better to do this in the first days in front of the mirror and make sure that your nails are short. Fill your empty lens case that was previously completely dried, to half the freshly rinsed solution, put the lens inside and close the lids.

Note: All soft lenses solutions are not used for hard lenses. Do not change your recommended solution or use a solution that is not recommended.

Note: You can apply theses same recommendations for removing the lens from your left eye.

If you experience any of the following symptoms, contact your ophthalmologist immediately:

 1. Eye irritations

 2. Abnormal tearing

 3.  Eye discharge (the secretion of the eyes)

4. Abnormal light sensitivity

5. Red eye

6. Itching and burning eyes

 7. Blurred vision

8. Inflammation of the eyelids, puffy eyes

9. Eye pain

10. vision loss

Note: When you call an ophthalmologist or emergency department, it is better to have your contact lenses and lens case with yourself, as they may be used for microbial samplings and cultures.

  For more guidance, contact our ophthalmologists in Tehran-Iran Noor Eye hospital on-line through the phone number, 00982182400 or call our experts 24 hours a day.

How often contact lenses should be replaced?

 - Is it safe to wear contact lenses during pregnancy?




How often contact lenses should be replaced?

After the contact lens expiration date or seeing such symptoms as vision loss, eye tearing, eye pain, foreign body sensation in the eye, red eye or inflamed eyes the contact lens should be removed from the eye and replaced. Consult your doctor to ensure that you have the right time to use each lens.

 - Is it safe to wear contact lenses during pregnancy?

The use of contact lenses during pregnancy is limited. Usually, the state of vision of women changes during pregnancy, but returns to normal state about 6 months after delivery.

- Can I use contact lenses to treat  keratoconus?

 As the disease progresses, at the same time nearsightedness and irregular astigmatism develops so that in this stage your vision problems can not be corrected by wearing eyeglasses, and you have to wear hard contact lenses to improve your vision. Do not forget to consult an ophthalmologist before taking any action.

-What are the symptoms of contact lens infections?

 Common symptoms include blurred vision, eye pain, eye discharge (the secretion of the eyes), puffy eyes, burning eyes and severe light sensitivity. With each item cautioned, remove the contact lens carefully and never put another contact lens in your eye. Place the lenses in your lens case that is filled with fresh solution and refer to your ophthalmologist.

-What is the effect of sleeping while wearing contact lenses? 

This increases the risk of eye infection by 10 times. Sleeping while wearing contact lenses is to be avoided unless prescribed by your ophthalmologist and only about some kinds of contact lenses.

- Is it safe to use colored and cosmetic contact lenses which are sold in hair salons?

These kinds of contact lenses are not safe and not approved at all because any kind of contact lenses only should be prescribed by an ophthalmologist or optician.

- Does sharing the contact lenses with another person despite of observing hygiene and properly caring of them cause a problem?

Any kind of contact lenses is a completely personal healthcare device and sharing them with another person causes serious eye infections and irritations, so in some cases these eye infections and irritations are so severe that need to costly, complex treatments or even sometimes are impossible to treat.

- Can I wash my contact lenses with tap water?

 Because of the presence of solutes, bacteria and some fungi, using of tap water is not recommended for washing the contact lenses and lens cases, as it causes eye infections and irritations.