If the job seems to be slowing you down, you may simply need more light.
The psychology department at Florida State University in Tallahassee studied the effect of lighting in homes, offices and public places. As reported in the journal Human Factors, older people generally need more light for reading and other visual tasks. In fact, most older people light their homes more brightly than younger people do.
Even so, when researchers studied the effects of improved room lighting, they found that everybody -- regardless of age -- found it easier to read when the lights were turned up.