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Lens Care Guide

 

LENS CARE GUIDE

Have you ever had watery eyes and have felt envious of other people who don't seem to have that problem? Have you tried getting contact lenses of your own?

 

How do you choose the right glasses?

Kids should undergo a comprehensive examination by a professional, who will then recommend the correct prescription and advice under his or her supervision.

To find the best contact lenses for you, undergo a complete eye examination and a thorough discussion with the optometrist. 

Some factors to be considered are:

1. Eye condition (e.g. Do your eyes water OR dry up frequently?)

2. Eye curvature

3. Wearing time

4. Length 

Optometrists are very easy to find, as they hold office in their own private clinics. They are the best people to consult as they can give you professional guidance and advice.

 

What is inflammation and how does it feel?

The eye's cornea is layered by cells that contain a lot of sensory nerves that are very sensitive to pain. When your contact lenses come into contact with the cornea, this then produces an uncomfortable feeling and inflammation, watery eyes, and sensitivity to light (otherwise known as cornea irritation).

The cornea needs metabolism, and the best way to do it is through air!

The maintenance of corneal metabolism relies mainly on outside sources of air: 80% of the limbus vascular network by 15% and 5% room water supply.

During slumber, you can not directly supply oxygen to the cornea, so the alternate route is via the blood vessels.

Do not let your eyes “suffocate”! In America and Hong Kong, many young people are known to suffer cornea damage because of improper eye and lens care (e.g. not taking them off after a long night of partying). If you don't practice good lens/eye hygiene, your eye becomes prone to bacterial infections such as conjunctivitis.

Conjunctival inflammation symptoms include increase in eye pain, eye itching, and tears. In this condition, it is highly recommended that you stop using contact lenses and consult a doctor about antibiotic therapy until there is full recovery.

 

Can I wear lenses?

If you have certain eye diseases such as conjunctiva, cornea inflammation, trachoma, dacryocystitis, lacrimal duct blockage or a reduction in tear secretion, or nystagmus, you are not recommended to have contact lenses. Others whose eyes are more sensitive should also avoid wearing contacts. Even if it will make you look prettier, consider your health first and think of the consequences.

 

The following people should also avoid wearing contacts:

Environmental conditions: those frequently exposed to sand, dust, and volatile materials such as acid-base. 

Personal qualities: those with poor hygiene / cannot follow doctor's orders. 

Also, those who have undergone eye surgery to correct vision within 1 year cannot wear contact lenses.  

Primary and secondary school students are also not recommended to wear contacts, as they are in a crucial growth stage, which means their eye visual axis has not stabilized fully. Prematurely wearing lenses makes them prone to corneal hypoxia and other physical side effects like metabolic disorder.

If the lenses are incompatible with the cornea, this can also result in corneal abrasion, with severe cases further causing corneal ulceration or perforation.

 

When should I take a break from contact lenses?

Girls should avoid contacts when pregnant or menstruating.

1. The eyes become more sensitive during menstruation particularly for those who regularly have dysmenorrhea. 

2. Pregnancy and hormonal changes affect the body's water retention, which leads to eyelid swelling and the thickening of the cornea.

 

Can I wear contacts when I have a cold?

1. When you have a cold, there is a higher chance of experiencing eye problems/infections.

2. Sneezing causes a lot of bacteria to exit your system, and when this accidentally gets to your eye, can cause infections.

3. A cold promotes dry eyes, which is not a good environment for contact lenses.

 

Can I wear contacts while in transit?

1. Traveling long distances while wearing contacts can greatly reduce eye moisture, which can cause the lenses to dry up and harden.

True or False: The moister the eye area, the better environment it is for contacts

Answer: False!

The required moisture greatly depends on your activities, the environment and the condition of your eyes –remember that contact lenses themselves cannot produce moisture.

 

Factors to consider:

● Watery eyes: Select contact lenses with high water content

● Dry eyes: Select contact lenses with low water content  

Water with high oxygen permeability improves the lenses' performance. People also think that the softer the contact lens, the more comfortable it is because of the higher water content.

However, the truth is that water content that is higher than 50% will lead to the breakage and deformation of the lens. With a lower water content, you can be sure that the lens will last longer, help correct mild astigmatism, can be maintained over the years through semi-annual polishing, and can even be replaced annually.  

Over time, the moisture of the lenses evaporate! This will cause your eyes to feel dry.

Therefore, the kind of lens design you choose is crucial—it has to be aligned with your lifestyle needs for its purpose to be fulfilled.

 

What is oxygen transmission rate?

It is simply the speed that oxygen that passes into the lens. The higher this is, the more oxygen permeates.

If your lens oxygen permeability is low, it is almost like suffocating your cornea with a big mask. Your cornea then ends up trying to get more oxygen, which leads to corneal proliferative blood vessels—or the formation of red blood.

To put it simply, like a tree, their roots, or their main basis of survival is oxygen! 

If your lens does not have very good ventilation, they will not perform well.

Oxygen transmission rate = DK / T 

Where DK is the air permeability and T is the thickness

Water content percentage, or the material, will affect the degree of oxygen permeability 

 

Lens 101 for those who already use it

Make sure you wash your hands before putting on those lenses! Don't be lazy as you may be the cause of the inflammation of your eyes. Once you have washed your hands, don't touch anything else unless your contacts are safely in your eyes.

Check your lenses before wearing them and be wary of small specks of dirt, sediments, and more. If there are any, your lenses must be washed and clean prior to wearing them. If your lenses have broken, throw them away and don't attempt to put them in your eyes. You will need to get new ones.

Clean, wash, disinfect and store your lenses in a secure place. Allow sufficient time for your lenses to be sterilized – more than 4 hours will do. 

If you have a useful protein remover pill (for the protein precipitates), remember not keep your lenses in for more than 12 hours! 

Otherwise, the small molecules or dissolved sediments will be re-attached to the lens, making them more difficult to clean! 

Get yourself a lens solution! Go to the pharmacy and select the best brand-- don't just order off the internet. The solution should be placed in dry areas-- but be wary of the toilet as this is the perfect breeding place for bacteria! 

Don't use the solution after 1-3 months, as they may also be a breeding place for bacteria.  

If you prefer to use eye drops, please remember to buy special ones for contact lenses.

If you use regular eye drops, eye drops, your lenses will break down faster. Also, never use your eye drops a month after its recommended use. 

Young people, be careful of makeup. Don't let your mascara, eye shadow or eye liner enter your contact lenses. If they do, proceed to cleaning the lenses. Avoid leaving your lenses in the toilet and replace them after 3 months if they were never used since then.

Be careful when opening a contact lens package. Open the package carefully, place the lenses on your palm, add a few drops of solution, rub them gently and allow them to open on their own.

 

Blur 

Contact lenses blur when there is mist or a speck of dirt in the eye. In this case, lenses must be cleaned or replaced. Another reason may be that the lenses were not positioned properly inside your eyes.

Base Curve

Contact lenses are also subject to wear and tear, and if you have been wearing them for a long time, it may be time to have them replaced. If your myopia worsens with the lenses, the base curve may be too small. You should go and have another examination to adjust your lenses.  

Eye redness

1. Acute Congestive: This may be due to a bacterial infection caused by overnight wear, lens contamination, corneal abrasions, ulcers and so on. 

Severe symptoms include pain, photophobia of eyes, and tears. If there are white spots on the cornea, you may have keratitis. 

You should remove the lenses and seek medical care immediately.  

2. Chronic congestive heart: The congestion may be caused by accumulated dirt and sediments.

 

The Dry Eye Syndrome and Solutions

Normally, tears contain a very thin layer of lipid on the surface to prevent evaporation. 

After wearing the lens, this layer of lipid will not be as stable, so it speeds up the evaporation process.  

1. Environmental factors: Air-conditioning, heat, smoke, excess wind that enters the eyes.

2. Lens wear and tear, excessive sediments (use of protein remover), oxygen permeability

Solution: Quality maintenance of lens

3. Lenses are too tight, teary eyes, bad circulation, corneal edema, hypoxia

Solution: Check if the base curve is not too tight or loose, or get low water content lenses

4. Lens dryness from wearing lens for too long (e.g. wearing them overnight)

- Reduce the amount of time you wear your lenses

5. Your young one needs professional help due to dry eyes

It's time to stop using contact lenses!

What you should do:

- Artificial tears, lubricant use, not more than five times a day in order to avoid illness to cover up 

- If necessary, to take Vitamin A and B2 (ask your doctor for a medical opinion before proceeding)

If your lenses do not feel comfortable after 4-5 hours of use and all you feel is a burning sensation, there are several possible reasons for this: 

1. Lens are too tight lens – this “suffocates” the eyes, shutting it out from oxygen and vital nutrients, which can possibly lead to corneal edema

2. You have been using your lenses for too long, which leads to excessive protein precipitation

3. Your lenses have ventilation problems

 

Other Information on Lenses

Why did you consider lens shape?

Some eye drops, such as chloramphenicol, Chloromycetin and Dicaine eye drops can change the lens diameter 

Heat disinfection and chemical disinfection method, when used simultaneously, may result in disinfection of the lens' polymer material composition and reaction, thereby affecting the physical properties of the lens.

Lens sediments. Some lens sediments will lead to the hardening of the lens and the reduction of its diameter.

Permeation of the osmotic pressure can affect the lenses.

Solution (lens syrup) can keep the parameters of the lens in the normal range. However, if there is high osmotic pressure, the lens diameter is reduced;   pressure is low, the lens diameter increases. 

So do not use tap water, drinking water or distilled water for your lenses.

Your will know your lenses are aging when they become deformed and  start to curl. 

 

Contact Lenses and UV Rays

Lenses, with the addition of UV-absorbing material monomers,  can block 99% of harmful UV-B rays and 80% of UV-A rays. 

Ultraviolet rays enter the eye through the cornea, causing major eye injuries such as cataract and snow blindness.

As the lenses are close to the eye but not covered by the surrounding eye tissues, sunglasses will not relieve the strong sun or snow glare. 

Therefore, when outdoors, it is necessary to wear them with UV protection sunglasses. 

Compared with the normal function of contact lenses, multi-layer anti-UV lenses protect you from UV-induced visual impairment, making sure your eye's health and safety are safeguarded. 

 

Computer versus contact lenses

Amy writes:

"I use the computer on a daily basis, but as soon as I'm home, I take off my contact lenses."

FACT:

Wearing contact lenses during prolonged use of the computer should be avoided.

Research states that even though there are different brands now offering high quality contact lenses, all of these are prone to degradation from computer radiation exposure, causing the original material to decompose and a new crystal to form via lymphatic circulation, resulting to a new polymer.

Generally speaking, when a small amount of polymer leaves the eyeball and goes to the eye surface, it's fine. But when this happens multiply times, the debris accumulates inside the eyeball, forming a cataract.

The experts' advice is to avoid wearing contact lenses when using the computer for a prolonged period of time, and give your eyes time to rest, discharge waste and rejuvenate—all in order to avoid cataracts.