CORRESPONDENCE 221

much in this summary to interest a stu-dent of visual theory. For example, the variations among different subjects with normal color vision in the position of the spectral zone for pure yellow are plaus-ibly accounted for by supposing the ex-istence of an individually varying propor-tion of the number of receptors for red aand for green combined with a mass ac-tion giving more weight to the central im-pression of a fundamental color compo-nent when the number of its excited receptors is greater. Furthermore the perception by a congenitally yellow-blue-blind observer (the famous case of Al-rutz) of the short-wave end of the spec-trum as "red with black spots" may be explained in the same way. Even the highly elaborated theory of Miiller does not seem to do quite as well on these points.

D. B. Judd.

GENERAL AND PLASTIC SUR-GERY. By J. Eastman Sheehan, M.D. 1st Edition, clothbound, 345 pages, 495 illustrations. New York and London, Paul B. Hoeber, Inc., 1945. Price $6.75. This book, which is the fifth in the

career of the author, is not primarily a text for ophthalmologists but rather a treatise on general surgical techniques with an emphasis on war injuries.

The first four chapters deal with the agents which produce war wounds, the nature of such wounds, wound excision, and the control of wound infection. The author points out that prior to World War II, reliance was placed chiefly on bactericidal action, but after the power of the sulfonamides to induce bacteriostasis was demonstrated, attention has cen-tered on this later method. Some space is devoted to the use of sulfonamides and penicillin. Chapter five deals with the sub-ject of burns and their treatment. It is

encouraging to note that he recommends that the tannic-acid treatment be aban-doned and the wound be treated as an open wound with special attention to the elimination of infection and replacement of lost skin as early as possible. The ma-jor portion of the text is devoted to the care of wounds, and an attempt has been made to cover the whole field of surgery. The section on wounds of the face in-cludes wounds of the orbit, and the dis-cussion on reparative procedures about the eyes is brief and incomplete. The chapter on tissue replacement demon-strates the different types of skin flaps and classifies skin grafts on the basis of their thickness. Some attention is devoted to the Padgett dermatome, and there is a discussion of plasma and white-cell fixa-tion of grafts and the use of other ma-terials for plastic repair. The last two chapters are devoted to the healing of wounds and elaboration on the details of surgery for repair of the nose, the mouth, facial contours, the eye, and the ear.

The illustrations, which are numerous, consist chiefly of line drawings, and there is a tendency to oversimplification.

The book is interesting and contains much informative material but it is not comprehensive enough to be classified as a complete reference book on modern op-erative methods. No one can be expe-rienced and well informed in the whole field of surgery, and, in our present day of specialization, the need is for books which cover a small field thoroughly rather than those which cover the whole field inadequately.

Irving Puntenney.

CORRESPONDENCE PRESBYOPIA ASSOCIATED WITH

ALTERNATING SQUINT

Editor,

American Journal of Ophthalmology:

222 CORRESPONDENCE

I have been unable to find in the lit-erature or texts any mention of the ad-vantage to which alternating squint may be put in connection with prescribing lenses for the presbyopia Nevertheless, a presbyopic patient with alternating squint can be made comfortable for both distance and near vision without the use of bifocals. I presume that others may have used the same means as I to accom-plish this, for the method is simple and the results are greatly superior to those obtained with conventional glasses. How-ever, if my method has been used be-fore, no ophthalmologist appears to have taken the trouble to publish it, nor has it been mentioned in any textbook on re-fraction.

The method is simply to supply a dis-tance lens for one eye and a near lens for the other. With a little patience and demonstration with the trial frame the patient readily learns how to use such glasses. If he is sufficiently presbyopic to need a +2.50 D.sph. addition, he can be given a distance lens for one eye and a bifocal for the other. The upper part of the bifocal would contain an addition of +1.25 D.sph. and the lower part an addition of +2.50 D.sph., the segments set high—up to the lower edge of the pupil. Thus he obtains the equivalent of a trifocal without being subjected to the inconveniences his neighbors have with their bifocals!

Care must be taken to differentiate be-tween occasional squint and true alter-nating squint; for if a patient with the for-mer type of strabismus is supplied with

these glasses, he will probably complain of diplopia or blurring. However, I have one patient who has an occasional squint with an exophoria of 30D. and who so disliked his bifocals that, in desperation, I suggested he try the method I have just outlined. He managed successfully to suppress vision in the non-used eye and went happily about his work with an al-ternating extropia which gradually grew to 50D.

Should the strabismic patient see well with both eyes but nevertheless use one eye almost exclusively, it might be ad-vantageous to prescribe a bifocal for the dominant eye and a distance lens for the less-used eye. The patient can then use the dominant eye for both near and dis-tance, but can switch to the other eye when going downstairs, walking over rough ground, and at other times when he requires good vision for distant objects below the level of his bifocal segment.

If one does, routinely, the simple muscle tests that are necessary to obtain a good eye examination, one will discover quite a number of presbyopic patients with alternating squint.

I do not know of any more grateful patients than these. All their lives they have considered their eyes inferior to the eyes of their neighbors. Now, finally, they can be told that the opposite is true—they belong to a very exclusive group of people who will never need to wear bi-focals !

(Signed) L. J. Alger, M.D. Grand Forks, N.D.