Introduction
If you’ve ever been to an eye doctor, you may have heard the term “BC” thrown around in the context of contact lenses. But what does it actually mean? In this article, we’ll dive into the world of contact lens prescriptions and explain exactly what BC is and why it’s important.
What is BC?
BC stands for “base curve,” which refers to the curvature of the back surface of a contact lens. This curve is important because it determines how well the contact lens fits on the eye. If the base curve is too flat or too steep, the contact lens may not sit properly on the eye, which can cause discomfort, irritation, and even vision problems.
How is BC Measured?
BC is measured in millimeters and typically ranges from 8.0 to 10.0, with increments of 0.1 or 0.2. The base curve is determined by taking precise measurements of the curvature of the front of the eye, known as the cornea. This measurement helps the eye doctor select the best contact lens for the patient’s unique eye shape and prescription.
What Happens if the BC is Incorrect?
If the BC of a contact lens is incorrect, it can cause a range of problems. If the base curve is too steep, the contact lens can press too tightly against the cornea, which can lead to discomfort, redness, and even corneal abrasions. If the base curve is too flat, the contact lens may not sit securely on the eye, which can cause the lens to move around and blur vision.
How Does BC Affect Contact Lens Comfort?
One of the most important factors in contact lens comfort is the fit of the lens. If the base curve is correct, the contact lens should sit comfortably on the eye and move naturally with each blink. If the base curve is incorrect, the contact lens can cause discomfort, dryness, and irritation, which can make it difficult to wear the lenses for extended periods of time.
How is BC Different from Diameter?
While BC refers to the curvature of the back surface of the contact lens, diameter refers to the overall size of the lens. Diameter is also measured in millimeters and typically ranges from 13.0 to 15.0. The combination of BC and diameter helps the eye doctor select the best contact lens for the patient’s needs.
Can BC Change Over Time?
Yes, the base curve of the eye can change over time due to a variety of factors, including age, pregnancy, and certain medical conditions. It’s important to have regular eye exams to ensure that your contact lens prescription is up-to-date and that the lenses you’re wearing are still the best fit for your eyes.
Conclusion
In summary, BC stands for “base curve” and refers to the curvature of the back surface of a contact lens. The base curve is an important factor in contact lens fit and comfort, and an incorrect base curve can cause a range of problems. By working with an eye doctor and keeping up with regular eye exams, you can ensure that your contact lens prescription is up-to-date and that you’re wearing lenses that fit your eyes properly.