He was wearing 2-year-old glasses. A trial frame showed no change.
National Eye Institute, National Institutes of Health
|Right or left eye||Refractive error||Cylindrical error
--correct for astigmatism
|OD||-0.50 D||+0.50 D x 07°||+2.50 D|
|OS||-0.25 D||+0.25 D x 177°||+2.50 D|
OD = oculus dexter = right eye
OS = oculus sinister = left eye
D = diopter
This shows that Dr. Cole had only a small degree of myopia (nearsightedness) and astigmatism (irregularity) and was using a standard bifocal (+2.50 D).
"Stronger" conventional glasses would improve neither his distance nor his near visual functioning. To enhance his visual performance, he would need the extra magnification provided by low visual aids. "Stronger glasses" might seem logical but are contraindicated for distance tasks. The image size needed to be increased, and this could be achieved by the use of low vision aids.