Introduction  

Silicone hydrogel contact lenses are breathable soft contacts that allow plenty of oxygen to reach the cornea. They are more porous and allow more oxygen (up to five times) to get to the cornea than regular soft contacts.The FDA approves silicone hydrogel contact lenses for extended use for up to thirty days. They are the most popular lenses in North America.

Types

Silicone hydrogel lenses are of three types:

  • Toric lenses – Different zones of the lens have different powers 
  • Spherical contact lenses – Have uniform power across the optical part of the lens 
  • Bifocal contact lenses – Have two different power areas for distance and near vision
     

Patients have a wide choice including:

  • Daily disposals – These are single use contacts that are removed and thrown away at the end of each day. One has to wear a fresh pair of contacts the next morning.
  • Six-day extended wear – This type of lens can be worn for up to six days.
  • Two-week daily wear - These are worn daily and have to be cleaned and stored overnight. They are used for two weeks and replaced afterwards.
  • Monthly daily wear - These are used daily for a month and changed for a fresh pair. One has to remove, clean and store them overnight.
  • Thirty-day continuous wear lenses – These are low maintenance lenses and can be worn throughout for up to thirty days.
     

Uses

Silicone hydrogel contact lenses are among the safest and effective vision correction devices for people with vision problems. They are used to correct vision disorders including:

  • Presbyopia 
  • Astigmatism  
  • Farsightedness 
  • Nearsightedness 
     

Selection Criteria  

These contact lenses are particularly useful to patients who:

  • Have high prescriptions
  • Need more oxygen supply to the eye 
  • Work for extended periods in low humidity air conditioning
  • Wear lenses for up to fourteen hours daily, including overnight wear
  • Experience the end of day dryness, discomfort or redness with regular soft contacts
  • Are younger and tend not to clean their lenses thoroughly or as often as recommended
  • Over-wear their lenses
     

Benefits

These contact lenses offer a range of advantages such as:

  • Lower risk of eye infection
  • Increased comfort and performance
  • Ideal for sports with a chance of impact
  • Extended wear for up to six straight nights and days
  • The material is more rigid making them easier to handle 
  • Continuous use, at times for up to thirty days before replacement 
  • Increased supply of oxygen to the cornea, which promotes eye health
  • Help reduce eye conditions such as dryness, redness corneal inflammation and corneal infections
  • Prevent deposits from building up which means less drying of the lenses and less irritation in the eyes
     

Prescription

The US Food and Drug Administration (FDA) regulates all types of contact lenses. One needs a prescription from a licensed eye care practitioner to get them. He/she conducts a complete eye exam to determine if the patient is the right candidate for the contact lenses. The professional makes sure the lenses fit well and he/she teaches the patient how to care for them.

Side Effects

Wearing contact lenses may lead to side effects such as:

  • Redness
  • Itchy eyes
  • Eye discomfort
  • Distorted vision
  • Corneal abrasion
  • Severe eye infections
  • Corneal inflammation
  • Less tear exchange when blinking
  • Increased risk of contamination
     

Interactions

Silicone hydrogel contact lenses can be used with eyeglasses. 
One must seek professional advice before applying eye drops. 
Sharing lenses can lead to sight-threatening eye problems.

Care Instructions

To prevent complications and to enhance the visual experience, patients are encouraged to remove their lenses before sleeping. Guidelines for the care of lenses include:

Washing hands well before handling lenses 
Keeping the lenses clean and well looked after
Getting medical advice and regular eye checks
Sticking to the wear and replacement schedule
Buying the contact lenses from a legitimate source
Following all the instructions around contact lenses and lens products
Using artificial tears or lubricating eye drops several times a day to keep the eyes moist