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Can I Purchase Contact Lenses Using My Eyeglasses Prescription?

18-06-2023

A Contact Lens Prescription Is Needed To Purchase Contact Lenses

As individuals consider their vision correction options, it is common to wonder if they can use their eyeglass prescription to purchase contact lenses. While eyeglass and contact lens prescriptions serve the same purpose of correcting visual impairments, there are significant differences between the two. Below, we explore why a separate contact lens prescription is necessary and the factors that differentiate it from an eyeglass prescription.

Variances in Measurement

Eyeglass and contact lens prescriptions differ in how they are measured. An eyeglass prescription is typically based on the refraction of light entering the eye when the lenses are positioned approximately 12-14 millimeters from the eye's surface. On the other hand, contact lenses rest directly on the cornea, requiring adjustments in the prescription to account for this proximity. The curvature of the cornea plays a vital role in determining the contact lens prescription. Contact lens prescriptions include additional measurements, such as the base curve and diameter, to ensure a proper fit on the cornea. These measurements are specific to contact lenses and are not typically included in eyeglass prescriptions.

Personalized Contact Lens Fitting

Unlike eyeglasses, contact lenses require a personalized fitting process to ensure comfort, optimal vision correction, and eye health. During a contact lens fitting, an eye care professional evaluates various factors, including the curvature of the cornea, tear film quality, and the overall health of the eyes. Additionally, the fitting process considers the type of contact lenses best suited for the individual's visual needs, such as soft lenses, rigid gas permeable lenses, or specialized lenses for astigmatism or presbyopia. The prescription for contact lenses is customized based on these fitting assessments to ensure a precise fit that aligns with the unique characteristics of each individual's eyes.

Considerations for Eye Health

Contact lenses interact directly with the delicate surface of the eye (i.e., the cornea), making eye health a crucial consideration. An eyeglass prescription does not take into account factors related to the eye's health, such as the risk of corneal hypoxia or the potential for infection. During a contact lens fitting, eye care professionals assess the eye's health, looking for signs of any existing conditions that may affect the safe use of contact lenses. They also educate individuals on proper contact lens care and hygiene practices to minimize the risk of infections or other complications associated with contact lens wear.

Wearing Schedule and Material Specifics

Contact lens prescriptions also include information about the wearing schedule and the recommended replacement frequency for the lenses. Contact lenses are available in various modalities, such as daily disposable, bi-weekly, or monthly wear. These recommendations are tailored to the specific lens type and the individual's visual needs. Furthermore, contact lens prescriptions specify the material of the lenses, as different materials offer varying levels of oxygen permeability, moisture retention, and comfort. Selecting the appropriate material is crucial to ensure comfort and maintain good ocular health.

Regulatory Considerations

It is important to note that purchasing contact lenses without a valid contact lens prescription is illegal in many jurisdictions, including Canada. Contact lenses are considered medical devices, and regulations are in place to protect the wearer's eye health. These regulations require contact lenses to be prescribed by a licensed eye care professional after a thorough evaluation.

While it may be tempting to assume that an eyeglass prescription can be used to purchase contact lenses, the differences between the two prescriptions make it clear that a separate contact lens prescription is necessary. Contact lens prescriptions take into account factors such as the corneal curvature, personalized fitting, eye health considerations, wearing schedule, and material specifics. It is essential to consult with an eye care professional for a comprehensive contact lens fitting and to obtain a valid contact lens prescription. This ensures that contact lenses fit properly, provide optimal vision correction, and maintain eye health.

Schedule a contact lens eye exam and fitting today with our Edmonton optometrists today!

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