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					                                         Abstracts

                     Papers presented at the Sectional
                      Meetings of the Association for
                        Research in Ophthalmology
                                    Southeastern Section
                                           March 22, 1964
                                           Gainesville, Fla.


Sugar and sugar alcohol levels in the                        osemonophosphate shunt in lenses of galactose-fed
lenses of lactose-fed rats                                   rats and can result only in the diversion of more
                                                             TPNH from its normal function.
J. F. R. Kuck, Jr.
   Twelve rats on a control diet containing 60               The inhibition of cholesterol-induced
per cent glucose were compared to an experimental            iris deposits in rabbits with
group of 24 rats on 60 per cent lactose, a level
sufficient only to produce peripheral vacuoles in
                                                             dietary magnesium
6 days. When the experimental values for days                M. L. Kwitko, J. Wener, M. A. Simon, and
4, 5, and 9 are averaged and compared with the               K. Pintar
corresponding control values, the results are as
follows: blood glucose 97 mg. per cent (experi-                  The feeding of a high cholesterol diet to albino
mental); 113 mg. per cent (control); blood total             rabbits soon results in lipid depositions in the iris
reducing sugar 144, 129; blood galactose (by                  (lipidosis). The addition of a magnesium supple-
difference, i.e., TS-Glu) 47, 16; blood galactose            ment to this high-fat diet causes inhibition and
 (by galactose oxidase) 37, —; lens glucose 13,              modification of the deposits.
8, 5.6; lens fructose 18.2, 9.5; lens polyols 1,                 Two groups of 25 rabbits were given diets of
120, 13; lens lactate 89, 108; aqueous glucose 91,           43 Gm. of rabbit pellets, 6 Gm. of oleic acid, and
92; aqueous fructose 5.4, 4.0; aqueous polyols 21,           1 Gm. of cholesterol daily. Magnesium chloride
2; aqueous lactate 65, 63; body weight 79, 93;               was added to the drinking water of one group.
lens weight 21.0, 21.3. The striking increase in             This group consistently showed diminished iris
lens polyols has been noted before but the in-               lipidosis. The effect of magnesium on iris de-
creases in lens glucose and fructose are unexpected          posits was correlated with levels of serum choles-
in view of the identical aqueous glucose levels in           terol, potassium, magnesium, sodium, chloride,
both groups. Since aqueous lactate levels are the            calcium, and inorganic phosphorus. Additional
same in both groups, and the lens lactate is not             comparisons were made between iris lipidosis and
significantly (p=0.21) depressed by lactose                  atherosclerosis of the aorta.
feeding, there does not appear to be an impair-                  The experimental diets resulted in highly ele-
ment of glycolysis. The increases in lens sugars             vated serum cholesterol levels in both groups of
are to be contrasted with the depressed levels of            animals. The serum magnesium level of the rabbits
amino acids, potassium, and glutathione, which               receiving a supplement of magnesium chloride was
others have found in this situation. The simplest            significantly higher than that of the group of
explanation is that in the lactose-fed rats there is         animals placed on the high-fat diet alone. There
increased permeability of the lens to glucose with           was a close correlation between the fatty deposits
a resultant higher level of lens fructose produced           in the iris and aorta. The reduction of the iris
via the sorbitol pathway. It is noteworthy that              deposits was associated with diminished athero-
this increased production of fructose (as indicated          sclerosis of the aorta and occurred despite the
by an increased level of aqueous fructose) occurs            fact that highly elevated serum cholesterol levels
in spite of the depressed activity of the hex-               were not altered by the magnesium feeding.

                                                       235
236 Abstracts                                                                      Investigative Ophthalmology
                                                                                                    April 1965




Effect of preillumination upon responses                accumulation by melanin granules is sharply de-
of the corneoretinal potential to                       pendent on the drug concentration in the medium.
                                                        The saturation concentration of 18 /tg of chloro-
subsequent illumination                                 quine per milligram of dry tissue is in accord
C. D. McCord, Jr.                                       with the levels found in pigmented rat iris after
                                                        prolonged oral feeding. The findings suggest a
   Change of illumination induces damped oscilla-       possible relation between high drug dosage and
tions in the indirectly recorded human corneo-          the development of toxic retinopathy.
retinal potential. Duration and amplitude of the           It was found that increased acidity of the
oscillation depend on the intensity of the light        medium decreased the chloroquine binding to
used. In the present experiments it was investi-        melanin. The observations are in accord with our
gated whether a preceding exposure to light affects     previous data on the enhancement of urinary
the oscillation evoked by subsequent exposure to        chloroquine excretion in humans following acidi-
light. Changes in the corneoretinal potential were      fication with ammonium chloride.
recorded in ten test subjects by means of hori-
zontally placed nonpolarizable electrodes and a         AC versus DC amplification of the ERG
DC recording system. The eyes were moved ever)'
10 seconds over a 45 degree angle in the hori-          R. H. Peckham, W. M. Hart, and J. K. Peckham
zontal plane. The difference in potential between          Recent publications of the ERG in both animals
two eye positions, which is proportional to the         and humans show the use of both AC (condenser-
corneoretinal potential, was recorded. The test         coupled) and DC (resistance-coupled) amplifiers.
subjects were exposed periodically to 12.5 minutes      The difference between the two systems can result
of light and to 12.5 minutes of darkness. Three         in quite different forms for the ERG pattern,
intensities of light were used. The potential           which may result in quite different interpretations
difference between preperiod mean and peak              of the resulting electrictemporal relationships.
 (equal mean to peak amplitude), the potential          These differences are especially important when
difference between peak and following trough            the b-wave is used as an index of retinal sensi-
 (equal peak to trough amplitude), and the po-          tivity. Examination of simultaneous AC and DC
tential difference between preperiod mean and           ERG's shows that the AC record represents a
trough (equal mean to trough amplitude) were            sometime distorted first derivative of the DC
used as parameters. The first response to light         potential generated at the retina and reflected from
(mean to peak amplitude) after 90 minutes of            the cornea. Thus AC records of the b-wave repre-
dark adaptation served as individual calibration.       sent the rate of change in the DC b-wave poten-
All parameters were light-intensity dependent. The      tial rather than the amplitude of the DC potential.
slope of the regression lines differed significantly.   Depending upon the time constants of the ampli-
The ratio of the slopes for mean to peak ampli-         fier coupling, slowly alternating stimulus changes
tude versus mean to trough amplitude was about          may be most greatly distorted, while rapidly
3:1. The spontaneous oscillation following pre-         alternating stimuli, as in "flicker electroretin-
illumination did not affect the response evoked by      ography," may be remarkably trustworthy. Com-
subsequent illumination when the second light           parative examples of the two systems will be
stimulus was one-tenth or one-hundredth of the          shown with frog electroretinograms.
intensity of the first light stimulus, and was
separated by 12.5 minutes. It is concluded that         Slow periodic oscillations in the
individual calibration and periodic light stimulation
afford the condition for quantitation of the re-
                                                        primate ERG
sponse of the corneoretinal potential to different      P. Gouras and R. E. Carr
light intensities.
                                                           In attempting to achieve steady state conditions
                                                        at relatively high light levels for the rhesus monkey
Binding of chloroquine to melanin granules              ERG, an interesting phenomenon has been ob-
                                                        served. Monochromatic sinusoidal or square wave
M. Rubin, A. M. Mansour, N. Zvaifler, and               stimuli of relatively large amplitude from either
H. Bernstein                                            end of the visible spectrum produce time varying
   A characteristic retinopathy associated with         ERG responses which do not come to a steady
protracted high doses of the antimalarial chloro-       state equilibrium for more than one hour after
quine has been related to the selective accumula-       the stimulus is initially presented to the dark-
tion of the drug in the pigmented ocular tissues        adapted eye. Within the first minute after stimu-
of experimental animals and in humans.                  lation, there is a series of oscillatory changes of
   The melanin pigment granule has been identi-         considerable magnitude. From this point on, how-
fied as the locus of drug deposition. In vitro          ever, there is a slow, continuous increase in the
binding studies show that the rate of chloroquine       amplitude of the ERG for approximately 5 to 10
Volume 4                                                                                 Abstracts 237
Number 2



minutes. Thereafter, the ERG amplitude pro-            ten normal test subjects under stable and under
ceeds to decrease and increase in a damped             changing illumination. It was found that, with a
oscillatory manner at a frequency of 2 to 3 cycles     single calibration, the error in the electro-
per hour. Although this effect is relatively small,    oculographic measurements depended upon the
it is quite reproducible. These changes in the         spontaneous or induced fluctuations in the corneo-
ERG appear to be completely in phase with the          retinal potential. At a test angle of 10 degrees the
simultaneously recorded transocular DC potential.      error can amount to 10 degrees of arc. However,
                                                       with bracketing the test potential by calibration
Intracorneal silicone fluid                            potentials every 10 seconds, an accuracy of 30
                                                       minutes of arc (mean) and a precision of 60 min-
D. S. Levenson, F. W. Stocker, and                     utes of arc (standard deviation) were achieved.
N. G. Georgiade                                        The method cannot be improved further until tech-
   Silicone fluid was injected into the stroma of      niques are developed to distinguish smaller poten-
rabbit and dog corneas. Practically no tissue re-      tials from "background noise." It is concluded that
action ensued. Corneal edema which followed            in all electro-oculographic studies frequent calibra-
artificial damage of the endothelium was confined      tions should be inserted between measurements.
to the area posterior to the silicone, whereas in
control corneas without silicone it comprised the      Breakdown of the active transport
whole thickness of the cornea. Several months          mechanism in the lens metabolism of
after the injection of silicone, the corneal stroma    the white rat
anterior to it began to atrophy and finally left a
craterlike defect which filled in with corneal         W. M. Hart, R. H. Peckham, and N. Moradi-Nik
epithelium.                                               Failure of the active transport system in the
   It was concluded that while intracorneal silicone   lens is first apparent within 24 hours of galactose
fluid would be of value in preventing fluid which      feeding. The first appearance of cataract is four
had penetrated the endothelial barrier from            days later. A loss in specific gravity is the first
reaching the epithelium, causing bullous kerato-       detectable change in the lens, followed imme-
pathy in cases of endothelial dystrophy, its use-      diately by a gain in lens weight and a loss of
fulness is restricted by the fact that blocking the    potassium and protein from the lens. Sodium and
flow through the corneal stroma probably causes        calcium accumulate to high levels. The lens ap-
a nutritional deficiency leading to atrophy. The       pears to maintain some measure of resistance to
silicone deposit was ineffective in producing a        these changes for about two weeks, at which time
significant increase in refractive power.              there is a precipitous loss of protein and potassium
                                                       from the lens.
Present limits of precision of                            Studies with gas chromatography show that
electro-oculography                                    galactose enters the lens only in traces while dul-
                                                       citol accumulates in high concentration. However,
A. W. North                                            dulcitol cannot be assigned the sole role of water
   Frequently the assumption is made that repeated     inhibition by the lens since postmortem changes
movement of the eye over the same angle of arc         in water and electrolytes are identical with those
results in a potential of constant magnitude           obtained by galactose feeding. The latter observa-
 (corneoretinal potential). This potential is in-      tion suggests that galactose feeding produces a
directly recorded in man by applying Ag-AgCl           slow death of the lens.
electrodes to the periorbital skin (electro-oculo-
graphy) and using DC amplification. It has been        Experimental studies of polysaccharide
demonstrated that the corneoretinal potential          metabolism in embryonic retina
undergoes fluctuations which occur either spon-
taneously or upon illumination of the eye. It is       B. Brown and D. Peck
therefore questionable whether the same magni-            Twenty-four hour intact neural retina fragments
tude of a recorded potential always corresponds        and monolayer tissue cultures were employed to
to the same angle of eye movement. Since there         study acid mucopolysaccharide production in 9- to
are fluctuations in the potential, an attempt was      12-day-old embryonic chick retinas. Periodic acid-
made to eliminate them as a source of error in         Schiff, toluidine blue, and the colloidal iron stain-
electro-oculography. Test angle measurements,          ing techniques were used to study the effects of
ranging from 5 to 30 degrees of arc, were              actinomycin-D, puromycin, or crude histones upon
bracketed by calibrations over an angle of 45          cultures of embryonic retina. To augment histo-
degrees of arc at 10 second intervals. When            chemical studies tritiated uridine, tritiated thymi-
variations occurred in the corneoretina, the test      dine,14carbon leucine, and 35sulfur were added
angle measurements were corrected correspond-          to the embryonic retina cultures. When results
ingly. Twenty experiments were conducted on            were compared, it was found that both puromycin
238 Abstracts                                                                       Investigative Ophthalmology
                                                                                                     April 1965



and actinomycin-D completely inhibited the up-         in cases of dystrophy, opaque grafts, and stored
take of 35sulfur while crude histones stimulated       corneas.
the uptake six hundred fold. Both of the antibiotics      In studying normal corneas, it appears that the
and the crude histones greatly inhibited the up-       viability of the endothelium (as evaluated by this
take of tritiated uridine, tritiated thymidine, and    procedure) varies greatly. Preliminary results in-
"carbon leucine.                                       dicate (1) corneas from older donors (especially
                                                       over 70 years) do not keep as well as those from
Oscillatory phenomena in the                           younger donors; (2) corneas which appear satis-
electro-oculogram of rabbits                           factory by slit-lamp examination may sometimes
                                                       have pathologic endothelium; (3) a progressive
G. A. Brecher, A. W. North, and H. Kolder              deterioration of the endothelium is easily seen by
   By using periorbital electrodes in man it is pos-   comparing paired corneas from eyes stored at 4°
sible to record a potential which is proportional      C. for varying lengths of time. By evaluating die
to the corneoretinal potential. This is done by        endothelium of corneas thought to be satisfactory
repeating eye movements over the same angle            for penetrating grafts, it may be possible to estab-
 (electro-oculography). The corneoretinal potential    lish standards which preserved corneas should
fluctuates spontaneously as well as upon illumina-     meet.
tion of the eyes. It displays fast oscillations with
a period of about 2.2 minutes and slow oscillations    Difficult readers and visual factors
with a period of about 25 minutes. The purpose         related to the problem
of the present investigation was to determine
whether corresponding fluctuations of the indirectly   L. F. Gray and J. H. Shipp
recorded corneoretinal potential occur also in rab-       The stimulus for this paper has been the peo-
bits. The eye of a rabbit was moved passively over     ple who come to our offices with the chief com-
the same angle every 10 seconds. The corneo-           plaint that they could not read or were slow
retinal potential was measured with electrodes         readers. The object is to present causative factors
placed subcutaneously in the periorbital tissue and    of the more severe reading problems, organic and
DC recording system. Before each experiment the        functional. The variety of problems encountered
illumination condition (light or dark) was kept        is unusual.
constant until the potential became stable. It was        It is our conclusion that, with the facilities avail-
found that, like in human subjects, the potential      able today for educational evaluation, correction
increased witih illumination and decreased in dark.    of visual problems, and neurological evaluation,
With cyclic light changes two resonant frequencies     the alexic or nonreading child can no longer be
were noticed. One had a period of 2.2 minutes          ignored. Any child seen for an eye examination on
and another a period of 38 minutes. The potential      the basis of a reading problem should have special
of the fast oscillations increased in dark and de-     attention by the ophthalmologist, and the possible
creased in light. The potential of the slow oscilla-   need for psychometric testing and neurological
tions increased in light and decreased in dark.        evaluation should be considered. The response to
Urethan temporarily enhanced the corneoretinal         adequate treatment and remedial methods in this
potential. Both urethan and pentobarbital reduced      group of children of normal intelligence has been
the response to cyclic changes of illumination.        excellent.
The corneoretinal potential increased in hypo-
volemic hypotension. It is concluded that this ex-     Some immunologic aspects in keratoplasty
perimental technique is reliable enough to investi-
gate conditions which cannot be produced in man.       W. /. Geeraets and I. R. Lederman
                                                          Heterogenous corneal grafts have been examined
A study of endothelium in keratoplasty                 by the agar-diffusion technique after storage in
and corneal preservation                               host corneas, recipient blood serum, and various
                                                       solutions. The results were compared with the
/. E. Robbins, J. A. Capella, and H. E. Kaufman        reactions resulting from freshly obtained corneal
   The intact cornea is removed from the eye with      tissue and that stored under refrigeration witliout
a rim of sclera and then aerobic enzymes are           being in contact with any medium other than the
stained with p-nitroblue tetrazolium. With this        saturated air. The results indicate that there is a
stain the cytoplasm of alive, intact, metabolically    demonstrable loss of precipitating antigenicity
active cells of the endothelium stained blue, mak-     after the graft has been placed in a suitable me-
ing an evaluation of the status of endothelium         dium for about 24 hours. Storage of the graft or
simple and reliable. The normal appearances of         whole donor eye, witliout being submerged in a
human and rabbiti endothelium, as demonstrated         suitable medium, does not result in such loss. In
by this technique, are presented. This is con-         vivo experimentation is in progress in order to
trasted with the appearance of the endothelium         evaluate the clinical usefulness.
Volume 4                                                                                   Abstracts 239
Number 2




Artificial drainage tubes for glaucoma                   ized ciliary body displacement. Tonographic stud-
                                                         ies were compatible with this idea.
R. D. Richards and O. P. van Bijsterveld
   Polyvinyl U tubes introduced by LaRocca were
used in nine eyes for eight patients with open-          Steroids and aqueous humor dynamics
angle glaucoma. Intraocular tension remained             M. B. Waitzman and R. T. Jackson
lower than preoperative readings in eight eyes
during the observation period of 9 to 18 months.            Evidence has been presented that while single
Despite the large channel from the anterior cham-        administration of 100 meg. of aldosterone given
ber to the subconjunctival area, and the placement       subconjunctivally was ineffective in changing
of the conjunctival incision on the limbal side of       aqueous chemical composition, repeated daily ad-
the scleral opening, the filtration blebs gradually      ministration for two weeks of 60 meg. topically
decreased in size and apparently ceased to filter        and 50 meg. subconjunctivally of aldosterone did
after 6 months. No inflammatory reaction was             result in marked IOP reduction—particularly for
found to account for this progressive change. The        a long period after treatment was stopped. Two
lowered intraocular pressures persisting after filtra-   other adrenal corticoid-like steroids, i.e., Decadron
tion had ceased were thought to be caused by             and Depo-Medrol, also reduced aqueous fluid pres-
 decreased aqueous production secondary to local-        sure following subconjunctival administration.

				
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