BMJ 1994;309:1370 (19 November)

Letters

The sight test fee 1988 data may be misleading

1988 data may be misleading

EDITOR, - We question D A H Laidlaw and colleagues' assumptions concerning the lower than expected rate of referrals to Bristol Eye Hospital.1 Their argument is based on an extrapolated linear regression line produced from five data points for 1984-8.

The national press first mentioned the possible introduction of charges for eye examinations in October 1987. This must have had an impact on the number of eye examinations conducted at the end of that year. Not surprisingly, there was a much larger increase in 1988 before the introduction of charges and a subsequent decrease in the two years following. This rush to obtain an NHS examination in 1987-8 brings into question the validity of using these two data points. Although predicting trends from only three years' data is difficult, it is interesting that if the data for 1987 and 1988 are eliminated the resulting regression . . . [Full text of this article]


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Relevant Article

The sight test fee: effect on ophthalmology referrals and rate of glaucoma detection
D A H Laidlaw, P A Bloom, A O Hughes, J M Sparrow, and V J Marmion
BMJ 1994 309: 634-636. [Abstract] [Full Text]

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