ICAC Online Learning Environment

Different Types of Contact Lenses and How They Work

Contact lenses improve vision by resting on the eye's surface. Some are worn during the day and removed before bed, while others are reused after overnight cleaning. Each type has its own wear and replacement schedule. To avoid complications, follow your doctor's advice. The sale of contact lenses continues to rise. According to Contact Lens Australia, yearly growth has been steady due to factors such as advancements in lens technology, increased accessibility through online retailers, and a growing preference for contact lenses over traditional eyewear.

What Are Contact Lenses?

Contact lenses are thin, round lenses that improve vision by sitting on the eye's surface. Like glasses, contact lenses correct refractive errors, which refer to changes in the shape of the eye that prevent light from properly reaching the retina, causing blurry vision.

Contact lenses help with the following refractive errors:

• Nearsightedness (myopia)

• Farsightedness (hyperopia)

• Age-related farsightedness (presbyopia)

• Astigmatism

Types of Contact Lenses

There are many types of contact lenses. Your eye care professional can advise you on the best one for you. Four main factors to consider are:

1. Lens material

2. Wear schedule

3. Replacement schedule

4. Special features

Lens Material

Contacts can be soft or gas permeable. Most people prefer soft contacts. Here's an overview of each type:

• Soft Contacts
  Soft plastic lenses are flexible and comfortable for most people. Many adjust to wearing them within a few days. However, these lenses can easily absorb pollutants like lotion or soap from your hands, which can irritate your eyes. They are also more prone to tearing or ripping.
  
  

• Gas-Permeable Contacts
  RGP (rigid gas permeable) lenses are harder than soft lenses. They use silicone polymers, unlike older hard lenses. This durable material allows oxygen to reach your cornea. RGP lenses retain their shape better than soft lenses and can provide clearer vision for some types of corrections. However, they may feel less comfortable when first worn, and it may take weeks to adjust.
  
  

Wear Schedule

You can wear daily or extended-wear contacts.

• Daily Wear
  These contacts are worn during the day but must be removed at night. You should not sleep in daily wear contacts, as this increases the risk of eye infections. Depending on your replacement schedule, you either discard the contacts at night or clean and store them for reuse the next day, following your provider's instructions.
  
  

• Extended Wear
  Extended wear lenses can be worn day and night, including while sleeping, for up to 30 days, depending on the type of lens and your doctor’s recommendation. However, you should always remove them for a night of rest, and wearing them continuously can increase the risk of eye infections. Be sure to discuss the risks with your provider.
  
  

Replacement Schedule

Your replacement schedule dictates how often to replace your contact lenses. This applies only to soft lenses, as RGP lenses are worn until your doctor prescribes new ones.

Soft contact lenses generally follow two main schedules:

• Disposable Daily
  With this schedule, you wear new lenses every day. Simply replace them in the morning, wear them all day, and discard them before bed. Never reuse daily disposables, as doing so can lead to eye irritation or infection. This schedule is ideal for people with allergies and helps reduce dry eye disease and contact lens irritation.
  
  

• Planned Replacement
  This schedule requires you to wear contacts all day and remove them at night. Instead of discarding them, you clean and store them overnight. With proper care, these lenses can last up to 30 days. Never wear contacts overnight unless they are specifically designed for extended wear.
  
  

Special Features

Some contacts have features to help with specific eye conditions or provide additional benefits. These include:

• Hybrid Lenses
  Hybrid contacts have a soft outer ring surrounding a durable RGP center. They may be more comfortable than RGP lenses while still providing clear vision. Hybrid lenses are ideal for people with astigmatism, corneal ectasia, or other irregular corneas.
  
  

• Toric Lenses
  Toric lenses are specially designed for astigmatism. They can be made from either soft or RGP material and are typically two-powered, like bifocals—one part corrects astigmatism, while the other corrects myopia or hyperopia.
  
  

• Multifocal Lenses
  These lenses enhance both near and distance vision. They are highly recommended for people with nearsightedness and age-related farsightedness (presbyopia), as each lens corrects vision at different distances with two or more prescriptions.
  
  

• Scleral Lenses
  Scleral lenses are a type of RGP lens that are larger than regular RGP lenses. The edges of the lens rest on the sclera rather than the cornea, creating a small gap between the lens and cornea that keeps the eye lubricated. Scleral lenses are helpful for treating dry eye disease and other corneal conditions.
  
  

• Orthokeratology (Ortho-K) Lenses
  These specially designed hard lenses are worn only while sleeping. They reshape your cornea to correct nearsightedness, and the effect can last throughout the day. Your provider will determine how often you should wear these lenses.
  
  

• Cosmetic (Decorative) Lenses
  Cosmetic lenses alter the appearance of your eyes. They can change your eye color or even make you look like an animal. While they can improve vision, they don’t always do so. All cosmetic lenses require a prescription, even if they don’t change vision. They need proper care and should never be purchased from non-prescription outlets, as non-prescription lenses can damage your eyes. In the U.S., it’s illegal to sell non-prescription lenses.
  
  

Who Should Not Wear Contacts?

Although contacts offer many benefits, they may not be right for you if:

• You have dry eye disease

• You experience recurring eye infections

• You have severe allergies

• You spend a lot of time in dusty or fume-filled environments

• You may not be able to properly clean and care for your lenses

Consult your provider to determine whether contacts are suitable for you.

How to Wear Contacts Safely

Ask your provider for personalized advice. These general tips can help reduce complications:

• Handwash
  Always wash and dry your hands with a clean, lint-free towel before touching your contacts. Use lotion-, oil-, and perfume-free soap, as these can leave a residue that irritates your contacts and eyes.
  
  

• Clean Contacts and Storage Case
  Follow your provider’s instructions for cleaning your contacts and their storage case. Never clean your lenses or case with water or saliva, as these can contain germs. Only use contact lens cleaner, and use the type your provider recommends.
  
  

• Avoid Water on Contacts
  Contact lenses and water should never mix. Even clean water can contain microscopic germs that cause eye infections. Avoid wearing contacts in pools, hot tubs, or baths.
  
  

• Remove Contacts Before Bed
  Unless your lenses are medically approved for overnight wear, always remove them before bed to reduce the risk of eye infections.
  
  

• Replace Contacts and Cases According to Schedule
  Replace your lenses and their storage case according to your provider's schedule.
  
  

How to Insert Contact Lenses

Inserting contacts becomes easier with practice. Here are the general steps:

1. Wash and rinse your hands thoroughly.

2. Always start with the same eye to avoid mixing lenses.

3. Use your dominant hand to insert the lens.

4. Rinse the lens with solution (not water), then check for damage and ensure the lens is not inverted.

5. Secure your eyelids and bring the lens to your eye.

6. Place the lens gently on your cornea, then release your eyelids and blink several times.

Repeat the process for the other eye.

How to Remove Contact Lenses

Follow these steps to remove contacts:

1. Wash and dry your hands.

2. Pull down your lower eyelid with your middle finger.

3. Lightly touch the lens with your index finger and slide it down to the white part of your eye.

4. Gently pinch the lens between your thumb and index finger to remove it.

Contact Lens Beginner Tips

Here are some answers to common questions for contact lens beginners:

• Should I wear contacts before or after makeup?
  It’s best to insert your contacts before applying makeup to avoid getting cosmetics on your lenses.
  
  

• Is it possible to wear contacts with long nails?
  Short fingernails make inserting and removing contacts easier. If you prefer long nails, discuss safe contact use with your provider.
  
  

• What happens if I fall asleep with my contacts in?
  If your prescription doesn’t allow for overnight wear, remove your contacts before bed. If you accidentally fall asleep in them, check if they move freely when you wake up. If not, use rewetting drops, and wait 10 minutes before removing them.
  
  

• Do I need glasses if I wear contacts?
  Always keep your current prescription glasses. If you experience an eye infection or your contact lens tears, you may need glasses.
  
  

• Will my contact prescription change?
  Yes, your prescription may change over time as your vision changes. Children under 21 may need new prescriptions as their eyes grow, and presbyopia can develop after age 40.
  
  

• When should I call my eye doctor?
  Contact your eye doctor if you experience any of the following:
  
  

  • Eye pain or discomfort

  • Redness in one or both eyes

  • Sensitivity to light

  • Sudden blurred vision

  • Excessive watering of the eyes

  • Fluid escaping from your eyes