Probably no topic is more confusing, misunderstood or underappreciated than how the choice of lens base curve can impact the optics, fit and cosmetics of a new pair of prescription glasses. In single vision lenses, it’s rarely thought about since a finished lens is typically used, out-of-the-envelope, and the base curve is whatever base curves the manufacturer or lens designer has chosen. That leaves the ECP completely out of the decision. Advanced free-form SV lenses can deliver vision as good as or in some cases, better than contact lenses. The improvements and the reasons why every eyeglass wearer inherently wants and today deserves the panoramically wide, sharp vision possible from this state-of-the-art lens technology.

So what should an optician do when they see a prescriber write “match base curve” on a new Rx? Ignore it? No... understand it.

Wrapped up in the phrase “match base curve” is a window to a previous time when lens design and fitting lacked the robust tools we have access to today. Of all the parameters impacting wearer adaptation and comfort, one of the few besides the prescription under the prescriber’s control is the changes in magnification and perspective a patient experienced from changes in base curve. However, free-form design now allows the optician to make the best base curve choice for the glasses at hand. For example, that means it may be more important to match the frames’ curve, rather than the lens’ former best base curve. Think wrap prescription eyewear. And since the optician is ultimately the one responsible for patient satisfactory fulfillment of the Rx, their wheelhouse demands they be given the option of selecting the base curve which strikes the best balance in the eyewear’s optics, fit and cosmetics. Good luck. May all your base curves be chosen wisely.

—Barry Santini, ABOM