🛑 Transposition of glasses prescription 👩👧👦
✍️ Glasses prescriptions can be somehow confusing.
✍️ learning to read them and work with them is much easier than what comes to the first look .
✍️ Transposition of glasses prescription is one of the most common actions when working in an optical laboratory and ophtha clinics
✍️ Some ophthalmologists prescribe eyeglasses in what is called plus cylinder, and others do so in minus cylinder.
✍️ Regardless of which is used, the prescriptions are the same and This can be proven by transposition of glasses prescription.
Let’s give an example of Transposition of glasses prescription
✍️ if one takes an eyewear prescription with OD
-2.75 -1.00 x 25
✍️ one can transpose this rather simply with a few steps in mind.
✍️ the sphere power needs to be changed by adding( algebraic summation) the second number or cylinder power to it.
☝️ So the sphere power of OD -3.75
✍️ the second number, or cylinder power, will always be the same with a sign change when transposed( opposite sign).
☝️ Therefore, the cylinder power will be +1.00
✍️ one of the most important steps is to add 90 degrees to the axis, which is the last number in the prescription.
✍️ regarding the axis if it exceeds 90 ( substract 90 ) if below 90 ( add 90 )
☝️ so the axis will be 115
☝️ This gives you a totally transposed prescription that looks (-3.75 +1.00 x 115)
✍️ Both the (-2.75 -1.00 x 25 ) and (-3.75 +1.00 x 115 ) are the same prescription(Rx) although they appear totally different! It is just that simple.
✍️ Let’s give another example of Transposition of glasses prescription with different signs
-2.00 +1.00x 90
☝️ The sphere will be -1.00
( algebraic summation of -2.00 added to +1.00 )
☝️ The cylinder power will be the same with opposite sign -1.00
☝️ The axis will be 180 ( 90 +90 )
☝️ So the final prescription form will be
(-1.00 -1.00x 180 )
✍️ Optical laboratories tend to work in minus cylinder as this is the way the lenses are ground for the final product ( to make the lens more thin and lighter) , therefore, it is vital for not only lab technicians to know but crucial for an Optician as well as an ophthalmologist .
✍️ All ur formulas for any refractive errors prescribed to a patient should be in minus cylinder form.
Transposition of glasses prescription Videos:
Optician Training: What Is Toric Transposition ( Transposition of glasses prescription ) and How Is It Done
Dr.Kafrawee optics .Transposition of glasses prescription – YouTube
Transposition of glasses prescription power point presentations:
Transposition of glasses
Transposition of glasses prescription:It implies transfer of lens power from one form to another so as to their meridian values remain the same in both the forms. It means rewrite the expressions of its power without actually changing them.
Transposition of glasses prescription