The Importance Of Properly Fitting Progressive Lenses
By Essilor News
Do you feel like your arms aren't long enough to read the newspaper anymore? Have you ever held the menu at a restaurant so far away from you that it caught on fire from the candlelight? You've always been able to see close up, so why do you find it so difficult now that you're over the age of 40? It's likely presbyopia.
Luckily, presbyopia isn't a condition that has to drastically change your life. The best way to adapt to this new challenge is to make an appointment with your eye doctor, who will most likely prescribe you a pair of progressive addition lenses (PALS).
Progressive lenses offer more advantages than bifocals (which only allow you to see better near and far) by allowing you to see clearly at all distances- near, far, and everything in between. Progressive lenses also eliminate the line in bifocals and make for a more seamless transition from looking in the distance to focusing on objects close up. The benefits of progressive lenses can only be experienced, however, when your glasses are properly adjusted to best fit your frames and the way the frames fit your face.
This is most often done by a trained optician. Opticians advise patients on frame and lens selection after they have received their prescription from the optometrist or ophthalmologist.
It is important to understand the impact your frame choice has on your lenses. Frame size is an important consideration when it comes to progressivelenses, because certain progressive lenses work better in different sized frames. Since progressive lenses allow you to see at all distances, it is important that the entire range of vision can fit within the frame. Therefore, frames with a very short lens tend to not fit progressive lenses as well as frames with a larger lens.
About 80% of the problems people have with progressive lenses come from fitting errors. Once your glasses return from the lab, the optician will have you try them on to conduct a final adjustment check and make sure they properly fit. If the prescription is not centered in the lens, it can keep you from being able to see clearly (e.g., when reading a book or walking down stairs). It's crucial that the lenses match up with the wearer's eyes, in particular, their pupils. This is accomplished through two measurements the opticians will take before ordering your new lenses: Pupillary Distance and Fitting Height. Pupillary Distance (PD) is the distance between the pupils. Fitting Height measures from the center of the pupil to the bottom of the lens for each eye.
When the optician places the glasses on your face to fit them, it's necessary that you maintain your natural posture. If you tilt your head at an angle to which you don't normally tilt it, errors in the Fitting Height measurement can occur. Wearing lenses that aren't properly aligned can cause the eyes to adjust to the lenses incorrectly.