588 M A R G U E R I T E Α. C O N S T A N T

ground color of the P A S stain but do not take the place of careful examination of morphology. The poor staining of nuclei is a disadvantage except when one is inter­ested primarily in the aldehyde-fuchsin posi­tive fibers or membranes. It is felt that the aldehyde-fuchsin stain may be a useful tool for studies of ocular pathology.

SUMMARY

A preliminary report on the use of the

aldehyde-fuchsin stain of Gomori for study of membranes of the eye is given. This stain combines the advantages of staining struc­tures stained by P A S or silver techniques in a simple, reproducible procedure. Of special interest is the observation that the markedly thickened basement membrane of the epi­thelium of the ciliary body of diabetics is not homogeneous as indicated by P A S stains.

640 South Kingshighway (10).

REFERENCES

1. Armed Forces Institute of Pathology, Manual of Histologic and Special Staining Technics, Wash­ington, D.C. (a) p. 82; (b) p. 70.

2. Gomori, G.: Aldehyde-fuchsin: A new stain for elastic tissue. Am. J . Clin. Path., 20:665, 1950. 3. Lillie, R. D.: Histopathologic Technic and Practical Histochemistry. New York, Blakiston, 1954. 4. Rinehart, J. F., and Abul-Haj, S. K.: Improved method for histologic demonstration of acid

mucopolysaccharides in tissues. A M A Arch. Path., 52 :189, 1951. 5. Fullmer, H. M . : Effect of peracetic acid on the enzymatic digestion of various mucopolysaccharides:

Reversal of the P A S staining of mucin. J. Histol. & Cytochemistry, 8:113, 1960. 6. Yamashita, T., and Becker, B.: The basement membrane in the human diabetic eye. Diabetes, 10:

167, 1961. 7. Pearse, A. G. E.: Histochemistry, Theoretical and Applied. Boston, Little, Brown, 1960, p. 162.

A N I S O M E T R O P I A A N D T H E F U N D U S C A M E R A

RoxALD M . BURNSIDE, M . D . , AND CHARLOTTE LANGLEY Dallas, Texas

The measurement of the percentage of anisometropia, optical aniseikonia, by the Carl Zeiss fundus camera has been under­taken in this study. In the past, the fundus has been measured by viewing it with the ophthalmoscope and using various superim­posed grids in the ophthalmoscope to meas­ure the blood vessels and the lesions of the eye. By ineasuring anisometropia with the fundus camera it is possible to obtain a purely subjective measurement of the two fundi to compare with the eikonometric readings and the calculated mathematical difference in the refraction.

Subjective measurements by the space eikonoineter are not particularly reliable in the very young patient and sometimes in the not so young. In cases of squint with or

without suppression, they may be of no value whatsoever. Thus, the photographs of the fundus that can be measured objectively on a projected screen-grid combination would seeiT! to be of value.

The new model Zeiss fundus camera is reflex free and it is possible in patients under 40 years of age with little or no inac-ular disturbance actually to visualize the foveal reflex in the finished projected fundus photograph. This fundus camera with its telecentric lens takes very accurate fundus photographs.

One hundred normal photographs were made to establish controls for this study. Corresponding fundus slides of the patients, matched for size to the right and left eyes, were projected with the Bausch and Lomb

A N I S O M E T R O P Í A A X D T H E FUNDUS C A M E R A 589

Fig. I. J . B.. right eye. 15 degrees. Fig. 2. J . B., left eye. H degrees.

Fig. 3. N. E. M.. right eve. 15 deg-ecs. Fig. 4. N. E. M.. left eye. \A degrees.

Fig. 5. S. Z. C . right eye. \4 degrees. Fig. 4. S. Z. C . lefl eye. II degrees.

Fig. 7. J . H.. right eye. 15 degrees. Fig. 8. J . H., left eye. 16 degrees.

Figs. I to 8 (Burnside and Langley). Anisometropia and the fundus camera. These pictures represent typical cases. (See table •or details.)

A N I S O M E T R O P I A A N D THE F U N D U S C A M E R A 591

projector on a flat aluminum screen at a dis­tance of three meters, 20 mm. on the screen representing one degree in the patient's eye. The findings were as follows:

Sixty-four of these patients (64 percent) showed the fundi of the two eyes to com­pare with a measurement of less than three mm. (0.15 percent) while 36 (o r 36 per­cent) had measurements of five mm. or less on the projection screen. The camera gave a flat 22-mm. diameter image, free of recog­nizable reflection defects of 30 degrees.

Corrections of less than — 16D. to -I-17D., as shown by measurement on the photo­graphic film, showed that one mm. equaled 1.0 degree 20 minutes in the patient's eye. On an average one degree corresponds to 0.75 mm. on the film. Answering a request for a formula for large corrective errors, Carl Zeiss of Oberkochen stated that the camera was very accurate within a — 16D. to a -l- 17D. Except for this information, no formula for corrections was available or considered possible.

In our series of patients, the variation in corrections was —6.25D. to -1-10.5D. Apha­kic patients gave a percentage of correction reasonable for the refractive difference. When measuring the fundi by this means, it is possible that the photographer may re­verse the film in processing; this may be checked by the retinal vessel pattern.

It was rather surprising that some pa­tients with an anatomic or cortical aniseikonia showed a significance difference in the meas­urements of the two fundi.

Table 1 surveys the findings in a series of patients who were measured by this proce­dure. The record of the vision shows the patient's degree of suppression and, in some cases, the visual improvement with the use of anisometropic lenses and by orthoptics. Extraocular muscle readings are those taken at the time of the measurements for aniso­metropia and, thus, are current. Eikono-metric readings are averages taken on co­operative patients of suitable age and in the absence of suppression. The last measure­

ment in the table is of the fundi of both eyes projected on a flat aluminum screen at a distance of three meters and shows the number of millimeters between the temporal edge of the disc and the center of the mac­ula. The grid lines on the fundus photograph are equal divisions of the 30-degree fundus photograph, each line representing an arc of two degrees.

The fundus photograph must be very sharp; ideally, sharp enough to see the fo­veal reflex pointing to the center of the fovea. A blurred photograph may be in or out of focus, which could produce an arte­fact in the size of the fundus image on the film. Three fundus photographs were taken of each individual eye and the sharpest fundus picture was used for this measure­ment, since we found that sharpness was a better criterion for accuracy than an aver­age of three fundus photographs for each individual eye.

It is possible to obtain an objective meas­urement or comparison of the expected ani­sometropia merely by direct visualization of the fundus photograph and by counting the difference in the number of lines between the two eyes. A short-cut in measuring is to accept one degree as equalling one-per­cent magnification in the lens to be placed in a patient's glasses.

SUM MARY

This study was undertaken to test an ob­jective means of accurately measuring the degree of anisometropia in a patient with an expected refractive error difference. The measurements seem to aid in prescribing the proper anisometropic correction for the pa­tient. It gives an added advantage in pre­scribing for patients with various degrees of suppression, in managing the young patient who is not reliable and in testing patients who give equivocal answers on the eikonom-eter. The fundus grid may be superimposed on the fundus photograph at the time of mounting or it may be made a part of the Zeiss camera by placing a photographic

592 R O N A L D Μ . B U R N S I D E A N D C H A R L O T T E L A N G L E Y

T A B L E 1

SURVEY OF FINDINGS

Ref Screen Slide Ini.ial Record E O M Fusio,, ^ ^ ^ , - - Visio. ^^Grid^^ « - - " - ' i -

1 WW 39081 37 i'Xnear III R1 .5X9Ü R20/20 - 5 0 0 . 5 0 R 1 % X 9 0 27S

L20/20 + 7 5 265

2 SP 0-8667 8 6°Xnear Supp OS R20/2S-»20/20 +125 0 .75 R l . 5 % 265

L20/80-»20/25 +450 2 8 2

3 JA* E-3943 36 4''Xnear III R l . O R20/20 - 1 0 0 0 .75 R I . 0 % 2,«)

L20/2Ü -100 235

4 LG E-022U 17 Normal R5/200-^20/30 +450 205^

Supp OD L 2 . 0 L20/2U +50 0.50 L 2 . 0 % 215

5 HWW L.1948 15 Normal ΙΠ Normal R20/40 -175 0.25 R 1 . 0 % 22,S^

L2Ü/20 - 7 5 230

6 C C H N-S763 33 8° Ε dist R20/20 +400 260^

Supp CD L20/2Ü +225 0 . 5 L l . S % 270

7 A J M L-1654 17 Normal HI R2Ü/20 X O 210

L20/20 -250 0.75 L 2 % X 1 8 0 225

8 ÜLH H-7671 27 8 ° dist III R 2 . 5 % R20/20 +75 0.75 R 2 . S % 210

L20/20 - 7 5 225 "

9 HRC M-59Ü3 39 4°Xnear R20/20 -225 2SÜ

Supp OS L2'7oX9Ü L20/25+ +100 0.75 L 2 % X90 265

10 C F J-6537 37 R20/20 +125 265

Supp O S L20/30 X O 0.50 L1 .25%X90 255

11 C R M M-2902 18 R20/20 -275 0 .75 R l . 0 % 245

L20/20 - 1 0 0 . 255

12 P S W M-2069 14 ID'E- lSEt R 2 % X 9 0 L20/25 +650 300

Supp OD L2n,20 +450 0.75 L l . 5 % 285

13 C A C P-171Ü 11 Normal HI Normal K20/20 +25 0 .50 R1.5';7c 290

L20/20 +400 280

14 J T W 11-1872 29 Normal III R 2 % R2Ü/20 +375 0.50 R1.57o 315

L20/2(l +550 305

15 GJM A-1902 4 7 4°Xnear III Normal R20/20 - 1 5 0 1 . 0 0 R l . 5 % 210

L20/20 +25 230

16 TRW J-8898 8 12''Xnear Supp O D R20/100 +425 265

L2Ü/20 X O 1.75 L 2 . 0 % 280

17 GBR* K-7696 50 Normal III R20/20 +50 240

L 1 . 5 % X 9 Ü L 2 0 / 2 0 + 5 0 1 . 0 0 L 1 . 5 % X 9 0 260

18 V A W A-5117 44 4° K20/20 X O 0.75 R l . 5 % 275

SuppOS L .75 X90 1 .20 /40 -^20 /20 +150 290

7 9 L D M^992 20 Normal III R20/20 - 5 0 1 . 0 0 R l . 5 % ^ 295

L 3.25 X 9 0 L20/20 - 1 0 0 275

i O ^ V W P Μ9841 T? 30° Ext Supp O D R 4 % X 9 « R20/10n +100 0 .50 R 1 . 5 % X 9 0 280

Ν 8°X L20/20 +25 270

21 E G R F-207 30 Normal III R2ÍX9U R20/20 -450 250

R 1 % X 9 0 L20/2Ü -300 0.25 L l . 5 % 245

* True aniseikonia, cortical. (Continued on next page)

A N I S O M E T R O P I A A N D T H E F U N D U S C A M E R A 593

T A B L E 1 (Continued)

Ref Screen

Slide Initial Record ^f, EOM Fusion ΕΛοηο- Vision ^^GrW^^ Corr̂ ection ^^^M^_

22 GDS P-2509 9 ó'Est Supp OD R20/20 +100 1.25 R 2 . 0 % 275

L i% L20/80 +500 300

23 JH M-911 20 Normal ΠΙ R20/20 XO 280

L 1 % X 9 0 L20/30 - 1 0 0 0.75 L 1 % X 9 0 265

24 BB C-6116 16 Est 1,11 R l . 5 % R20/20 - 4 0 0 0.50 R l . 5 % 300

Est ARC L20/20 - 5 0 290

25 RM L-8149 15 Normal III R20/20 -475 275

L20/30 - 6 0 0 1.50 L l . 5 % 245

26 BAG D-4208 13 Est 6 Supp OS R20/20 +150 1.50 R l . 5 % 280

L20/100 +400 350

27 PH 0-8926 22 Normal III R 1% R20/20 -225 1.25 R l . 5 % 250

L20/20 - 4 0 0 275

28 PVS Κ-4α42 13 Exp III L % X 1 8 0 R20/20 +25 0.50 R l . 5 % 255

L2O/20 +200 265

29 RJH #-6144 47 Hyper I, II R 2% R20/20 - 5 0 0.50 R 1% 215

L20/20 - 1 0 0 205

30 ED G5567 65 Normal III R 2% X90 R20/20 +350 260

L20/20 +150 0.75 L l . 5 % 245

31 JCH, Jr. L7422 47 Normal Supp OD R20/35 +175 285

L20/2G - 5 0 0.75 L l . 0 % 300

32 PW L9395 46 Normal III R 2 % X 9 0 R20/20 - 5 0 0.50 R 1 . 5 % X 9 0 250

L20/30 + 5 0 260

33 BMcK P2412 24 Normal III R 4 % X 1 8 0 R20/20 -475 250

L20/20 -625 0.75 L 1 . 5 % X 9 0 225

34 DS 02079 11 Normal II R20/20 - 2 5 1.00 R 2% 285

Supp OS L20/100-.20/30+300 265

35 MFM F1518 30 Est 20° Supp OS R20/20 +275 0.50 R l . 5 % 300

L20/80 +525 290

36 EW 22593 52 Normal III R i % X 1 8 0 R20/20 - 2 5 1.50 Rl .0%, 245

L20/60 +100 275

37 JWP F1480 39 Normal III L l . 2 5 % R20/20 - 5 0 0 215

L20/20 -375 0.50 L l . 0 % 225

38 ROS K8858 23 L 2.50X90 R20/100 +450 235

L20/20 +200 0.75 L 2 . 0 % 250

39 JDR D4056 47 Normal III R20/20 +175 210

L20/60 +125 0.50 L 1% 200

40 RAJ M3152 17 Normal III R 1 . 5 % X 9 0 R20/20 +325 2.00 R 1 . 5 % X 9 0 275

L20/20 +525 310

41 DEK D2415 40 Normal III R20/20 +175 380

L20/25+ +250 0.25 L l . 0 % 385

42 HP N8296 33 14° Ex III R l . 5 % R20/20 +150 0.75 R l . 5 % 235

L20/25+ +300 250

43 AWG N3371 24 Normal III R2Ü/20 -325 245

L20/20 - 1 4 0 0.75 L 2 . 0 % 260

(Continued on next page)

594 RONALD Μ. BURNSIDE A N D C H A R L O T T E L A N G L E Y

T A B L E 1 (Continued)

Slide Initial Record Age (yr.) EDM Fusion Eikono-

meter Vision Ref. Grid

(degrees) Correction

Rx

Screen 3 Μ.

(20 mm. = 1°)

44 GDW J2016 43 Supp OD R C F

L20/20

+550

+450 1.00 L 1%

295

275

45 MLG G1658 16 ARC R20/30

L20/20

+50

XO 0.75 L 1.0%

260

275

46 B.)W MS3I6 30 Normal ΠΙ L 1.0X90 R20/25

L20/20

+500

+450 0.50 L 1.0%

310

350

47 CRE E8747 20 Kormal III L 2% X90 XO I.OO

+225

R 1.5% 320

340

48 LR 5645 10 Normal ΠΙ R-400

L:600

R20/25

L20/20 0.5 L 1.5%

250

260

49 W R W t 53553 42 Normal ΠΙ R-375

L-300

R20/20

L20/20 L 1.5%

250

250

50 JHYf L1242 73 Normal ΠΙ R20/35

L20/30

+ 5 0

+ 1050

400

270

Normal variable: 6 4 % Show less than 3.0mm. orO.15%.

t Apliakia, O.S. Í Aniseikonia (?) patient noted point larger size. O.S.

plate of a low density in the focal plane of the Zeiss camera.

4105 Live Oak Street (21).

ACKNOWLEDGMENTS

W e are grateful to the Dallas Optical Labora­tories, Inc., for the photographic work, and to the Medical Arts Department of Southwestern Medical School, University of Texas, for preparation of photographic grid (which is available on request).

R E L A T I V E M E R I T S O F H E A D B O R N E , H A N D A N D S T A N D M A G N I F I E R S *

LOUISE L . SLOAN, PH.D . , AND DARLENE J. BROWN Baltimore, Maryland

INTRODUCTION

The first section of this paper presents an analysis of the special features of the different types of reading aids and of the factors which determine the acceptability of a given device. The second section pre­sents experimental evidence that the degree of visual impairment and the age of the

* From the Wilmer Ophthalmological Institute of The Johns Hopkins University and Hospital. This investigation was supported by grant B-810 from the National Institutes of Neurological Dis­eases and Blindness, Public Health Service.

patient are the major factors in determining the type of device he requires. It will be shown that the stand magnifier, though com­pletely ignored by many low-vision clinics, is often the only reading aid of any help to the elderly patient with marked impair­ment of central vision.

The primary function of a convex lens or lens system used as a simple magnifier is to reduce the divergence of the light from a very near object. It is the short distance of the object which is responsible for the increase in size of its retinal image. A s a