Referring to Zaidi et al's paper (Eye 2004; 18: 503–508), Marc Amsler was emphatic that his charts are to be used as a white grid on a black background. My own experience has confirmed that defects are much more easily picked up in this way. A pad of recording charts was included as a convenience but not as an alternative. Which charts were the patients given to use at home?

I was fortunate in 1946 to visit Professor Amsler in Zurich and he spent time explaining the use of these charts. He was emphatic that the chart was used as a white grid on a black background.

He told me how important it is to explain to the patient that the gaze must be fixed on the central spot while being aware of the whole chart. Questions were to be put in a strict sequence. Can you see the central spot? While looking at the spot and not moving your eye can you see the four corners? The four sides? Is any of the pattern missing? Distorted? Blurred?

In his paper delivered to the Oxford Congress, Amsler gave several examples of the usefulness of the test. (Amsler M. Quantitative and qualitative vision. Trans Ophthalmic Soc UK 1949; 69: 397–410, 9 Figs). Duke Elder also describes the method with illustrations (Duke-Elder S. System of Ophthalmology, Vol 7. Kimpton: London, 1962, pp 396–397).

In the booklet of Amsler charts, a pad of recording sheets was provided for convenience but not as an alternative. It appears that in recent years, the recording sheets have been given to patients at risk of macular disturbance asking them to use them at intervals to observe any distortion of the lines.

In my own practice, I have found that patients with central scotoma or metamorphopsia find difficulty in appreciating the defect on the recording charts, but do so easily on the proper white on black charts. This amply confirmed Professor Amsler's experience.