An example of glass prescription slip with interpretations.
Relevant terms to understand glass prescription slip:
1. OD (Oculus dexter): Right Eye
2. OS (Oculus sinister): Left Eye
3. OU (oculus uterque): Both Eyes
4. SPH (Sphere): Amount of lens power in dioptres required to correct near-sightedness (myopia) or far-sightedness (hypermetropia)
Correction is equal in all meridians of eye
If number has minus (-) sign: it is Myopia
If number has plus (+) sign: it is Hypermetropia
5. CYL (Cylinder): Amount of lens power for astigmatism
Correction in meridian specified by the prescribed axis
One meridian has no added curvature, and the meridian perpendicular to this “no added power” meridian contains the maximum power and lens curvature to correct astigmatism.
If number has minus (-) sign: it is Myopic astigmatism
If number has plus (+) sign: it is Hypermetropic astigmatism
6. Axis: The lens meridian that is 90 degrees away from the meridian that contains the cylinder power.
90 indicates “with-the-rule” astigmatism
180 indicates “against-the-rule” astigmatism
7. Near Add: Added magnifying power to the bottom of the multifocal lens to correct presbyopia
Always + even when not specified
Large difference in the power between two eyes (anisometropia) may lead to amblyopia in children. Hence, this is concerning.
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