974 A M E R I C A N JOURNAL OF O P H T H A L M O L O G Y NOVEMBER, 1968

OPTIQUE MEDÍCALE PRATIQUE. By Henri Saraux, Françoise Rousselie and Gabriel Coscas. Paris, Editions Doin, 1968. Paper-bound, 4 1 6 pages, index, 351 figures in black and white, 1 2 in color. This modern text on physiologic optics,

though elementary, is unusually comprehen-sive. A thorough discussion of geometric op-tics, including optical instruments and the optics of the eye, is followed by a systematic presentation of methods of examination and the various anomalies of refraction. The French still rely on reflecting mirrors for ret-inoscopy, but the Tarlet streak retinoscope is also described, an instrument similar to the original Copeland model. The various lenses are next considered: simple, bifocal and multifocal, including the plastic forms and the blended multifocal (Varilux). The Franklin-type bifocal and anti-reflection coating are not mentioned, however. A spe-cial trial case for the correction of aphakia is still used in France though not available in this country since World War II. In review-ing heterophoria, the authors note that exo-phoria and esophoria are helped when asso-ciated respectively with myopic or hyperopic corrections and that the reverse association has an aggravating effect, but they neglect to answer what to do then. Likewise, they de-plore the difficulties with bifocals that beset the presbyopic anisometrope, but without reference to slab-off, dissimilar segments and other serviceable measures. The fine chapter on sunglasses fails to inform how the color may affect the spherical correction. The material on illumination is surprisingly informative. The sections on aniseikonia, aids for low vision, spectacles for aphakia and contact lenses give due recognition to the works of Ogle, Fonda and Sloan, Welsh and Girard respectively, but in general chap-ter references are meager. The authors' en-thusiastic endorsement of the Jackson cross-cylinder, which has had little vogue in Europe, may hopefully stimulate its use.

James E. Lebensohn

DYSLEXIA: DIAGNOSIS AND TREATMENT OF READING DISORDERS. By Arthur H. Kee-ney and Virginia T. Keeney. St. Louis, Mosby, 1968. Clothbound, 182 pages, in-dex, 2 4 figures in black and white. $12 .00 . A national conference on dyslexia was

held in Philadelphia November 18 and 19, 1966, under the sponsorship of the American Committee on Optics and Visual Physiology. This book presents the papers from that con-ference combined with four informal ques-tion-and-answer sessions. Ophthalmology, pediatrics, neurology, psychiatry, psychology, and education were represented by the 1 4 participants. This diverse group offered broad coverage of the subject and a variety of opinions.

Reading disorders are classified into pri-mary or developmental dyslexia, and dys-lexia secondary to a variety of factors such as brain damage, emotional disturbance, poor teaching, lack of motivation, deprivation, distortion in language experience and the like. There is considerable disagreement con-cerning the frequency and importance of the various types of dyslexia and on the number of poor readers. Botel stated that incidences from 1% to 2 5 % have been described. He pertinently noted that incidence was much lower in children from "good school sys-tems."

According to Bender, Critchley, and Cruikshank, primary or developmental dys-lexia is the most important type of reading disorder. Critchley described the condition as possibly hereditary, found more often in males than females, independent of environ-mental factors, and not associated with gross neurologic defects. Each of the three work-ers has pet notions of what minimal abnor-malities characterize this group.

The neurologists were particularly con-cerned about whether an abnormality in a ce-rebral cortex center is responsible for pri-mary dyslexia. Buchanan speculated that a lesion in area 3 9 near the angular gyrus may produce reading defects. He noted that a vascular accident involving this area may