582 AMERICAN JOURNAL OF OPHTHALMOLOGY OCTOBER, I980

silicone band might incite an underlyingchoroidal inflammation. In 1969, Curtin!described similar pathologic changesafter retinal detachment surgery in apatient who died three days later. Curtinobserved choroidal engorgement and di­lated vessels overlying the buckle, andalso on the opposite side of the eye.Furthermore, his extended review ofmicroscopic slides of other cases in whichsilicone implant material had been useddisclosed a remarkable lack of reactionaround silicone implants. Curtin statedthat if inflammatory reaction was present,it was around suture material and not theimplants. These considerations suggest apossible initial diffuse, rather than local­ized, choroidal inflammatory response tocryotherapy, and one in which siliconehas little influence. Also in Dr. Fried­man's case, the possibility of a preexist­ing, that is, pretreatment, choroidal in­flammation associated with the retinaldetachment cannot be ruled out.

As far as the postoperative retinaladhesion is concerned, however, it isprobably more important to recognizepost-treatment changes in the retinalpigment epithelium and sensory retinathan in the substance of the choroid itself,inasmuch as these layers, and not thechoroid, are the ones primarily involvedin reestablishing the retinal adhesion.The pathologic changes reported in Dr.Friedman's letter might be related tochoroidal vascular changes after place­ment of an encircling silicone band.

Our own study of the effect of encir­cling silicone bands on ocular circulationdemonstrated a marked decrease in bothocular pulse amplitude and ocular rigidi­ty (unpublished data). Alterations of thissort could change the choroidal vascularsupply and contribute to choroidal con­gestion and edema on the basis of arelative insufficiency of the choroidalcirculation. Even so, this probably wouldnot create the adhesion between the

sensory retina and retinal pigment epi­thelium.

CARL L. FETKENHOUR, M. D.THOMAS L. HAUCH, M. D.

Chicago, Illinois

REFERENCE

1. Curtin, V. T.: Pathological changes followingretinal detachment surgery. In Symposium on Retinaand Retinal Surgery. St. Louis, C. V. Mosby Co.,1969.

BOOK REVIEWS

Epidemiology and Statistics for the Oph­thalmologist. By Alfred Sommer. NewYork, Oxford University Press, 1980.Softcover, 86 pages, 26 tables.

This brief, succinct text was written toprovide the ophthalmologist with a sim­ple, clear presentation of epidemiologicand statistical techniques relevant toconducting, interpreting, and assimilat­ing the most common type of clinicalresearch.

The first part deals with epidemiologicdefinitions, the use of controls, randomsampling, bias, sample size, standardiza­tion, and reproducibility. The secondportion of the text is devoted to theselection and use of statistical manipula­tions and testing the statistical signifi­cance of results. Dr. Sommer provides anumber of examples of good and baduses of statistical analysis from pub­lished reports.

He emphasizes sampling bias, whichleads to such conclusions as cataracts aremore common in patients with diabetes,whereas it is cataract extraction that ismore common in diabetics rather thanthe incidence of cataracts.

Since severe degrees of astigmatism orirregular astigmatism are treated withhard, rather than soft, contact lenses, it ismore likely that these patients will devel-

VOL. 90, NO. 4 BOOK REVIEWS 583

op keratoconus than those using softcontact lenses. Thus the two groups arenot comparable.

Dr. Sommer emphasizes the value ofprospective studies with adequate ran­domization. Thus, in one samplingscheme patients admitted on Monday,Wednesday, and Friday received oneform of therapy; those admitted on Tues­day, Thursday, and Saturday receivedanother. Referring physicians quicklylearned which therapy was given onwhich days and arranged for their pa­tients to arrive the day the therapy thephysician preferred was being given.

With Dr. Sommer's book in hand onecan certainly interpret medical readingwith far greater sensitivity. It is highlyrecommended for all who see patientsand read about them in medical journals.

FRANK W. NEWELL

Ocular Pathology. By C. H. Greer. Ox­ford, Blackwell Scientific Publications,1979. Hardcover, 281 pages, preface,index, 90 black and white figures.$35.75

This textbook is felicitously writtenand admirably succeeds in its objective ofencompassing the basics of ophthalmicpathology within a manageable length.Up-to-date concepts of inflammation, therole of the neural crest, and the latestWorld Health Organization classificationof eye tumors provide a firm gridwork foran authoritative discussion of these top­ics. The book is designed for those pre­paring for examinations, residents intraining, and fully trained ophthalmolo­gists who may want to review the subjectof opthalmic pathology. It would be par­ticularly useful for residents who aredoing a rotation in ophthalmic pathology,because its length allows reading andrereading over a four- to six-week period.While there are large treatises on oph­thalmic pathology for those who want

in-depth treatments of selected topics,the present book fills the void for thecasual reader who wants an overview ofthe field. I heartily recommend this bookto those who would like to whet theirappetites on ophthalmic pathology.

FREDERICK A. JAKOBIEC

Repair and Reconstruction in the OrbitalRegion, 2nd ed. By John Clark Mus­tarde. New York, Churchill Livingstone,1979. Hardcover, 400 pages, index,over 200 black and white figures. $85

This is the second edition ofa book firstpublished in 1966. It follows the sameformat as the first edition with the addi­tion ofchapters on hypertelorism and col­oboma. The first five chapters deal withreconstruction of partial-thickness de­fects of the eyelids and conjunctiva. Thenext six chapters deal with full-thicknesseyelid loss and surgery at the medial andlateral canthus. The basic principles ofskin surgery are presented in a clear andunderstandable manner, especially thoserelating to grafts and flaps. Each case iswell illustrated so that the reader canunderstand why the author chose a partic­ular method, how to perform the surgery,and the final result. Photographs andillustrations are used in combination toclarify the techniques. The author em­phasizes his own techniques for therepair of small defects all the way up toreconstruction after loss of both eyelids.

Unfortunately, the chapter on lacrimaldisease has not been updated to includethe newer techniques of canicular recon­struction such as the Quickert-Drydenmethod of silicone intubation. The chap­ter on socket reconstruction emphasizesolder techniques requiring external pres­sure on the socket and does not includethe technique of fixation to the orbitalrim such as presented by Callahan.Although most surgeons no longer recom­mend the Morel-Fatio spring for paralytic