Poor visual acuity in the reading area
A young patient who had poor va (6/12 to 15) wanted to be able to read books without having the encumbrance of a magnifier with her glasses. Her Rx is R +0.75/-1.00 x 60 and L +0.50 -1.00 x 120.
The way to enlarge an image on the retina is to bring the object for study closer to the eye. Simple enough maths. The distance lenses that put the image of the horizon exactly on the retina achieve the best possible vision. No hocus pocus – the image is either ON the retina and you DO, or it isn’t and you DON‘T get the best vision you can possibly get.
High add flat top 28 bifocal
We tried a + 4.00 add and that brings us to 25 cm adjusting the PD for ‘comfortable’ near. We then showed the patient 12 ½ cm (add +8 ). We settled on a +5.00 add (20cm) with a carefully adjusted PD. We also suggested a reading light and made a pair of bifocal lenses in a light attractive frame. Happy patient!
40 years’ experience.
Greenwood Optical, Brisbane.