Regularly scheduled eye examinations are an essential part of maintaining a lifetime of optimal eye health. While eyeglasses and contact lenses are some of the most commonly prescribed corrective eyewear, there are also other ways to correct refractive errors, such as laser refractive surgery. This webpage serves as a general guide, informing readers of the many vision correction options out there. For professional recommendations about your particular eye health, always seek the advice of your personal optometrist in Victoria.
Eyewear serves to correct refractive errors. Refractive errors typically result from the shape of cornea or inner lens not refracting light correctly. Some of the most common conditions that cause refractive errors include:
First designed in the 13th century, corrective eyeglasses have fortunately become more fashionable and sophisticated over the years. Eyeglass frames are available from numerous brands and in a nearly endless selection of styles.
Single-Vision, Bifocal and Progressive Lenses
After an eye examination, your optometrist may recommend either single-vision, bifocal, or progressive lenses. A majority of individuals with refractive errors start off with single-vision lenses, which only correct for distance. Later on in life, those that wear single-vision lenses may move onto bifocal or progressive lenses to address age-related presbyopia (loss of near vision) and other conditions.
Lens Prescription Levels
Eyeglass lenses come in a range of lens compression levels, referred to as the lenses’ “indexes.” Even among lenses of the same prescription, a thinner lens with a higher corresponding index number may be prescribed to bend incoming light more efficiently while still allowing room for the lens to fit in the frame.
Many new eyeglass-wearers are surprised to learn that most glasses aren’t actually made of glass, but high-strength, scratch-resistant specialty plastics. Lenses come in a variety of coatings designed to resist UV ocular damage, computer glare, as well as scratches and impact damage.
Depending on your prescription needs, your optometrist may give you the option of traditional- or digital-surfaced lenses. Digitally surfaced lenses use a diamond-pointed lathe cutter to precisely cut the lens from a semi-finished blank lens. Since less labour is involved, digital lenses are also completed faster.
Specialty Lenses and Frames
Are you currently working in an industrial setting or have sensitivities to screen glare when using computers? Your optometrist can most likely fit you with specialty frames, lenses, and glare-resistant coatings to improve your comfort and extend the performance of your prescription eyewear.
Lenses, tints, and coatings can be selected based on your personal preferences, but may also be recommended by your optometrist after discussing your profession or lifestyle.
Choosing the Right Frames
To ensure a comfortable fit, your optometrist may recommend eyeglasses of a particular lens width, frame size, bridge width, material, shape, temple length, and general fit. Your eyewear specialist will also look at the form of your face, size of your eyes, as well as temple lengths. These are all important aspects that need to be considered before selecting a particular size and style of frame.
The specialist fitting your new eyeglasses will take measurements to find your optical centres (OC) and pupillary distances (PD). Those with MSP coverage should note that these measurements are considered part of the fitting process and not part your optometrist’s prescription or annual checkup.
That’s a Wrap!
Once your newly cut lenses have been placed into your frames, the fitting specialist will have you try them on for fit, comfort, and optical clarity. If you notice any kind of discomfort, they will also adjust the frames to better conform to your unique facial structure. Periodic adjustments may be necessary to maintain the perfect fit.
The first functional contact lenses came about in the 1800s. Although these lenses were usable, they were entirely fabricated from glass and covered a majority of the visible surface of the eye. Fortunately, contacts have come a long way over the past centuries and comfortable, extended wear lenses are now much easier to come by.
Since contact lenses are considered medical devices in Canada, they do require a special prescription that varies from your typical eyeglass prescription. Your contact lenses must also be fitted by an eye care professional licensed to perform fittings. Each eye (even on the same person) is uniquely different. Therefore, certain considerations are necessary to ensure a proper fit. Wearing ill-fitting contact lenses can cause unintentional friction, corneal scratches, infections, and in serious cases, blindness.
Ensuring Your Contact Lenses Fit Properly
During your optometrist’s evaluation, they will determine whether contact lenses are the right option for you. This is based on several factors, including your ocular health and prescription level. If you have previously worn eyeglasses and have not experienced any recent changes in vision, your optometrist may simply convert your prescription over to contact lenses.
To find the appropriate style of contacts, your optometrist will measure the shape, size, and curvature of your eyes using a keratometer. They will also assess your general eye health, allergies, corneal health, as well as eye dryness in order to determine the right solution and lens composition. Each type of contact lens is uniquely designed with a particular function in mind. These functions include oxygen permeability, fit, curvature, material, moisture content, lifespan, and deposit resistance. Therefore, you should never switch contact lens brands before consulting with a licensed eye care professional.
Types of Contact Lenses
Multifocal Contact Lenses
Multifocal contact lenses function the same way as bifocals and progressive eyeglass, correcting refractive errors for multiple distances.
Scleral Contact Lenses
Scleral contact lenses are designed to sit atop the cornea and the whites of the eye. Scleral contacts are typically prescribed for those with chronically dry eyes, keratoconus (cone-shaped cornea), Sjögren's syndrome (autoimmune disease causing dry eyes), microphthalmia (a developmental disorder where one or both eyes are abnormally small), aniridia (absence of the iris), as well as other eye conditions, disorders, and injuries. As they are designed to overlap the sclera, scleral lenses are larger than regular contact lenses. These types of contacts also feature a reservoir over the cornea to moisten the area with artificial tears.
Decorative and Cosmetic Contact Lenses
Decorative and cosmetic contacts do not typically corrective refractive errors of your eyes, but are designed to alter their appearance and/or colour. Previously, decorative and cosmetic contact lenses were unregulated, but highly scrutinized for unintentional injuries to wearers. That changed on July 16th of 2016 when a new federal law came into effect that regulated contact lenses as a Class II medical device in Canada. Under this new regulation, cosmetic and decorative contact lenses can only be fitted by a licensed eye care professional.
Laser Refractive Surgery
Laser refractive surgery is known by most as “LASIK,” the most common form of laser refractive eye surgery. If you have been dreaming of the day when you could ditch those eyeglasses or contacts, laser refractive surgery may be your best option. This type of surgery is performed to correct refractive errors, such as:
Laser refractive surgery works by reshaping your cornea, the eye’s natural focusing lens covering the pupil and iris. Another type of eye surgery includes implanting a lens directly into the eye. Like all surgeries, laser eye surgery is not without its risks and is not recommended for those with certain medical conditions. To learn if you are a candidate for laser refractive eye surgery, first consult with your eye care professional.
Buying Contacts and Eyeglasses Online
While you can buy contacts and eyeglasses on the internet, be mindful that these products are unregulated and many do not use medical-grade materials or design standards. Researchers have found over 50% of eyewear purchased over the web failed at least one crucial parameter of optical or impact testing. Serious, permanent injuries have resulted from web-purchased contacts and eyeglasses, so always talk to an eye care professional before putting your eyes and vision at risk.