Cheap sunglasses seldom carry brand names, except for the misappropriated
name of Crookes —which by itself is meaningless. The original Crookes (Sir William, OM, FRS) never bothered to register the name of the protective glass which he invented, with the result that his name has been exploited by makers of coloured glass ever since. Genuine Crookes glass (made to Sir Wil- liam's formula at the Chance-Pilkington Optical Works) carries the company's name on a two- sided gold label, as well as on their warranty slip. But even the Chance-Crookes trade mark is not a complete guarantee that the lenses are optically plain, as Chance-Pilkington are glass makers, not lens grinders. Only an optician can provide that assurance.
But my optician, who is worldly enough to know that most people will continue to spend more on sun-tan lotion than on sunglasses, told me of two on-the-spot tests for anonymous sun- specs bought casually over the counter.
To test the neutrality of the lenses, gaze through one of them at an object in the middle distance (while holding the glasses at arm's length and moving them slowly up and down and from side to side). If there is no apparent movement or distortion of the object, the lens is neutral and safe to wear. Test both lenses in this way, as in cheap glasses they will not necessarily be matched.
To test the colour of the glass, lie the spectacles, lens side down, on a piece of white paper. This immediately reveals any variation in shade, which can be most tiring for the eyes.
Unfortunately, there is no test for the protec- tive value of the glass itself (with anonymous glasses the only guarantee is that two-sided gold label). Exclusion of the sun's harmful rays is not ensured by the darkness of the glass, or even by the metallic film of the mirror lens sun-specs.
. Nor is price necessarily any indication that the glasses will do their job. In the luxury class there are certain brand names which are a guarantee of quality (such as Polaroid, Zeiss, Rayban and Sun- bar). Yet, as Which? was able to show, sound sunglasses can be bought for a few shillings whereas others, costing four times as much, are merely ornamental (if that is the right word for some of those gaudy and misshapen frames).
Sunglasses, for me, fall smack between that category of things which ought to be cheap and expendable,' as they are bound to be lost (like umbrellas), and the things which it pays to pay for (such as shoes and saucepans). But 1 would
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