Many people consider the transition from eyeglasses to contact lenses for benefits like increased clarity, convenience, or purely aesthetic reasons. A common misconception is that the prescription for your eyeglasses is the same as for contact lenses. But it’s essential to understand that contact lens and eyeglass prescriptions are different.
Contact lens prescriptions have additional measurements that account for them being placed directly on the eye versus in front of the eye. Your eye doctor can provide you with an accurate prescription during a contact lens exam, which focuses on specific measurements of the eye in addition to overall eye health.
The Importance of Specific Prescriptions
At Eye Care for East Texas, we emphasize that obtaining an accurate prescription for contact lenses involves more than just adapting your current eyeglasses prescription. Contact lenses require distinct measurements to ensure they fit properly and correct vision effectively.
Differences Between Contact Lens & Eyeglass Prescriptions
While the prescriptions may appear similar, a contact lens prescription includes additional considerations beyond the level of vision correction provided by glasses.
Breaking Down a Contact Lens Prescription
A contact lens prescription includes:
- Base curve (BC): This crucial measurement of your cornea’s curvature ensures the contact lens fits correctly on your eye.
- Diameter (DIA): The contact lens size is specifically matched to the size of your cornea for optimal comfort and fit.
- Brand or type of lens: Your prescription will specify the recommended brand and type of lens because not all lenses are the same.
- Power (PWR or SPH): This element still determines the vision correction strength, similar to glasses.
Additionally, a contact lens prescription typically comes with an expiration date to ensure your eye health is regularly assessed.
Eyeglasses vs. Contact Lens Prescriptions
Glasses prescription example:
- OD (right eye): -3.00
- OS (left eye): -2.50
- Axis/cylinder (for astigmatism): -1.00 at 90 degrees
Contact lens prescription example:
- OD (right eye): -3.25 BC 8.6 DIA 14.2
- OS (left eye): -2.75 BC 8.6 DIA 14.2
- Specific Lens Brand or Type
These additional specifications in contact lens prescriptions highlight the customized fit required for lenses.
Converting Prescriptions: Why You Can’t Do It Alone
Simply put, you cannot directly convert a glasses prescription into a contact lens prescription. The physical positioning of lenses—whether on the eyes or a short distance from them—requires different prescriptions. A detailed eye examination and fitting process provides contact lenses that fit your precise requirements.
Exploring Contact Lens Options
When transitioning from glasses, there are a few types you can consider. Your optometrist can help you choose the right ones for you.
Rigid Gas-Permeable (RGP) Lenses
RGP lenses are durable, firm contact lenses that allow oxygen to pass through to the cornea. They provide sharp vision and are often used for correcting astigmatism or irregular corneas. Though smaller and less flexible than soft lenses, they are long-lasting and maintain their shape.
- Pros: Great for astigmatism, durable, and allows more oxygen to pass through.
- Cons: Require wear adjustment, can dislodge during activities.
Soft Contact Lenses
Soft contact lenses are made of flexible, water-absorbing materials, making them comfortable and easy to adapt to. They are ideal for daily or extended wear and are commonly used for correcting nearsightedness, farsightedness, and astigmatism. Soft lenses are available in various types, including daily disposables and monthly wear options.
- Pros: Comfortable, versatile for many wear schedules, stable for active use.
- Cons: Prone to tearing and require frequent replacements.
Specialty Lenses
There are several types of specialty contact lenses that you can discuss with your eye doctor:
- Multifocal lenses: A multifocal lens can correct both near and distance vision and is often used for presbyopia.
- Toric lenses: These specialized lenses for astigmatism feature different powers in specific areas to align with the eye’s shape.
- Scleral lenses: These large-diameter lenses rest on the sclera (white of the eye) and vault over the cornea, ideal for irregular corneas or severe dry eye conditions.
What to Expect During a Contact Lens Exam
There is no single answer for how a contact lens exam and fitting go because it can vary from person to person. But the process for fitting contact lenses typically involves:
- Vision tests to determine prescription needs.
- Measurements for corneal curvature and additional eye anatomy factors.
- Trial fittings to check comfort and vision accuracy.
- Instructional training for care and handling if you are new to contact lenses.
Regular Evaluations & Eye Health
Regular eye exams and contact lens check-ups are vital in maintaining eye health and updating your prescription as needed. Many factors, including lifestyle changes and shifts in vision, can influence your prescription needs and comfort. Your eye doctor can give you a personalized recommendation based on your situation.
Take Control of Your Vision
Understanding the distinction between eyeglasses and contact lens prescriptions empowers you to make informed decisions about your vision care. Choosing between glasses and contacts depends on personal comfort, lifestyle, and preferences.
At Eye Care for East Texas, we can provide contact lens exams and fittings that account for your unique needs. Contact us today to schedule an eye exam and discover the ideal contact lenses for your vision needs!
