Prescription Values

Hi my prescription is currently this: RIGHT SPH = -2.25, CYL = -0.5, Axis = 25 LEFT SPH = -0.75, CYL = -2.0, Axis = 180


It has been like that for at least 10 years but it has never felt right, every optometrist I have tried seems unable to find a more comfortable prescription.


Through my own experimentation I have realised if I move my glasses about 1 inch further away from my nose every things feels a lot better, and moving them 2 inches feels better again.


So big question is what is happening to my prescription when I do this? I know I am making it weaker by moving my glasses further away, but how much weaker? Can anybody tell me roughly what the prescription is changing to by moving the lenses in this way? Thanks!

 

A number of questions: 1) What style of lens are you wearing? Single vision? Progressive? 2) What material have you been wearing in your glasses? Plastic, Poly? 3) When you say your glasses have never felt right, what specifically do you mean? Blurry? Double vision? 4) Have your opticians ever tried working on compensating your RX based on vertex and anisometropia? What's happening is that as your vertex distance changes (the distance from the front of your eye to the back of the lens) you perceive less power in your lenses. If you were refracted in the phoropter ("Is it better 1, or 2?") at a vertex of 12mm and when you put your glasses on, the vertex distance is 9mm, your perceived Rx is going to be higher than what the doctor prescribed to you. The other factor you may want to take into account is that the astigmatism in your left eye is much higher than that of your right eye (that's the 'CYL') and there may be symptoms of asthenopia (fatigue of the eyes, headache, dimness) due to the resultant anisometropia. Anisometropia is when you have different prescriptions in each eye - usually not a problem with today's technology. Although, when there is a significant difference in the CYL correction between both eyes, some patients experience the discomfort mentioned before. These can typically be corrected with the right optician or optometrist.