Talk:NHS Optical Benefits in the UK

Author's Note:

There is some difficulty in finding the necessary resources for NHS voucher practice since most knowledge lies in the professional domain. However, most of the difficulty in understanding vanishes when it is discovered that the system depends on the use of one particular prescription-writing notation; namely greatest sphere power. Ordinarily there are two basic ways to write an optical prescription, one is good for the lens-maker and the other for voucher benefits.

These two prescription formats are equivalent: +3 +4 X 80     which means sphere  = +3  dioptre cylinder= +4 dioptres axis   = 80  degrees is equivalent to:

+7 -4 X 170    which means sphere  = +7  dioptres  This format is the one for the voucher table. cylinder= -4 dioptres axis   = 170 dioptres

Further, when the prescription containing the highest spherical power is used, it requires that a test lookup of the tables be done for each lens. The higher of the test values is selected to represent the voucher value for the glasses.

The above is the underlying intent of the voucher system, and is given here in case would-be formatters want to take a whack at it. Dig in. and by my guest. Armchair (talk) 11:40, 14 May 2009 (UTC)

Added 1.7em line-height to every paragraph to improve clarity. On the assumption that the page will be accessed by the visually-impaired, increased line spacing seems useful. (Armchair, 0830, 21 May 2009).

Armchair (talk) 21:11, 8 April 2009 (UTC)