Question
Dear Dr. Johnston,
My son got a prescription for contact lenses, and I'm trying to buy them on-line. However, I don't understand what are the numbers written in the prescription:
R: -275 (probably -2.75), -75 (probably -7.5), and +180 (probably +18.0)
L: same
Special notes: K: 43/45
I am having difficulties to find the contact lenses matching all the numbers. Is there any special brand of contact lenses with all these characteristics? What are these numbers?
Thank you in advance for your help.
Answer
From what I can tell, you do not specifically have a prescription for contact lenses. Was your son FIT with contact lenses, or did he just get a general exam with a prescription for glasses? It may be different in Canada, but in the US a contact lens prescription specifies a brand name of contact lenses, a Base Curve and a Diameter for the contact lenses, as well as the refractive data. While your "special notes: K 43/45" begin to hint at the needed Base Curve, they do not specify a curve and the curve chosen would depend on the brand of lens with which your son was fit.
I suspect your son did not receive a contact lens fitting, I suggest you return to the doctor and ask that he be fit. Usually this entails the doctor or an assistant placing the contact lens on the patient's eyes, assessing that they can see well with the lenses in question and that they fit on the eye properly and will not cause harm. Additionally for a new wearer, the contact lens fitting involves teaching the patient how to insert the lenses, how to clean them how often to replace them and how long to wear them. Moreover it entails guidelines for what can be done with the contact lenses on - sleeping: generally no, Swimming: no, shower: ok, short naps: usually ok, depending on what brand of contact lens was used. If you did not receive all these services, your son did not have a contact lens exam and cannot order them online.
The prescription you shared includes astigmatism correction, implying the need for toric lenses which call for even more involved fitting. Ordering these online without a proper fitting exam is dangerous to say the least. The online company from whom you are trying to order should demand a written copy of the contact lens prescription. If they supply the lenses without having that, they are breaking the law - at least in the US. Again, things could be different in Canada. But the laws we follow were written to protect people from damaging their eyes with contact lenses that don't fit properly or that do not provide proper acuity.
I hope you will follow through with a proper contact lens fitting for your son.
