Results of a partial cycloplegic on the visual syste

Maier, Bradley

Meuler, Dale

Williams, Larry

English

CommonKnowledge

Pacific University 
CommonKnowledge 
College of Optometry Theses, Dissertations and Capstone Projects 
5-1974 
Results of a partial cycloplegic on the visual system 
Larry Williams 
Pacific University 
Bradley Maier 
Pacific University 
Dale Meuler 
Pacific University 
Recommended Citation 
Williams, Larry; Maier, Bradley; and Meuler, Dale, "Results of a partial cycloplegic on the visual system" 
(1974). College of Optometry. 391. 
https://commons.pacificu.edu/opt/391 
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Results of a partial cycloplegic on the visual system 
Abstract 
Results of a partial cycloplegic on the visual system 
Degree Type 
Thesis 
Degree Name 
Master of Science in Vision Science 
Committee Chair 
Carol Pratt 
Subject Categories 
Optometry 
This thesis is available at CommonKnowledge: https://commons.pacificu.edu/opt/391 
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L 
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RESULTS OF A PARTIAL CYCLOPLEGIC 
ON THE VISUAL SYSTEM 
Results of a Partial 
Cycloplegic on the Visual System 
Presented to the 
College of Optometry 
Pacific University 
In Partial Fulfillment 
of the Requirements for the Degree 
Doctor of Optometry 
by 
Larry Williams 
Bradley Maier 
Dale Meuler 
May 1974 
l � 
L 
Table of Contents 
L Acknowledgment Page i 
Introduction 1 
Background of Cyclogyl 2-3 
Apparatus and Procedure 4-6 
Resu�ts and Discussion 7-10 
Tables of Data 11-12 
Graphs 13-24 
Summary 25 
. .  
ACKl�·owLEDGMENT 
The authors at this time would like to express 
their appreciation to Dr. Carol Pratt for his assistance 
as the sponsoring professor of this project. We are 
grateful for his thoughts and comments which helped 
guide us throughout this project. 
-i-
LRW 
Bffi·1 
Dr1M 
.Approved by 
M,...._.ay�, ....,,...1 =9=7�4�
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L 
INTRODUCTION 
Classically, cycloplegics have been used by 
some vision specialists to dilate the pupil and 
to inactivate the accommodative system, for . 
pathology detection and for determination of the 
refractive error. Drug concentrations used for 
this purpose are usually sufficient to completely 
paralyze the accommodative system for a short period 
of time. 
By diluting the standard cycloplegic solution, 
the authors attempted to partially inactivate the 
accommodative system. The effect of the diluted 
cycloplegic on the accommodative system and the 
phorias of the convergence system and their interaction 
was then determined. 
-1-
Research on the Background and Uses 
of a Commonly Used Parasympatholytic Drug: Cyclogyl 
Cyclogyl is a brand of cyclopentolate hydrochloride. 
Its chemical structure is 2- dimethylaminoethyl 1-
hydroxy-phenylcyclopentanacetate hydrochloride. Cyclogyl 
is provided in a sterile opthalmic solution with 
benzalkonium chloride as a preservative. 
Gyclogyl acts to produce both mydriasis and 
cycloplegia of such depth and duration that it can· 
be used clinically for a range of therapeutic. 
disorders. In general, these conditions are the 
same as those for which atropine is employed. Cyclogyl, 
however, expedites the desired response and, with 
rare �xceptions, eliminates unwanted atropine-like 
side effects. 
Cycloplegi� from the administration of Cyclogyl, 
attains a maximal degree in 30 to 60 minutes and is 
readily achievable even with patients with darkly 
pigmented irises. Using a standard .5%, 1% or 
2% solution, Cyclogyl usually produces complete 
relaxation of the iris and ciliary muscular process. 
-2-
Recovery from its adminstration is more rapid than 
with atrOpine or homatropine, being usually 3 to 6 
hours after use of a counteracting miotic or over­
night, if no miotic is used. Use of Cyclogyl leads 
to quite low residual accommodation; and only in 
rare instances, have toxic or allergic reactions 
been reported. 
Mydriasis from administration of Cyclogyl is 
attained to a profound extent in 30 to 60 minutes, 
with virtually no tendency to increase intra-ocular 
tension in normal non-glaucomatous patients. Its 
use has not been reported to cause ocular sensitivity. 
Besides mydriasis and cycloplegia, Cyclogyl 
is also used for the therapy of inflammations and 
lesions, such as iridocyclitis, keratitis and 
choroiditis, and to prevent synechiae or to free 
existing ones. Cyclogyl, however, should not be 
used where narrow-angle glaucoma is present. In 
rare instance� adverse symptoms of temporary duration 
similar to atropine side effects have been reported 
when the 2% solution has been administered to young 
children. These adverse symptoms have included 
ataxia, incoherent speech, restlessness, halluci­
nations, disorientation as to time and place, and 
failure to recognize people. 
-3·-
APPARA·rus and PROCEDURE 
The apparatus consited of a 20 foot examing 
room equipped with a Bausch and Lomb Greens Refrac-
tor, a reduced Snellen chart, and a cross grid 
target. In administration of the tests, both the 
pre-testing and post-testing conditions utilized 
the same testing procedures with the only differ­
ence being that the post-tests were given after 
the instillation of a 1:10 dilution of regular 
1% Cyologyl solution. 
The testing procedure included an estimation 
of the patient's iris pigmentation on a scale of 
one to five, with five being the darkest. Pupil 
size was measured with the various sized slit 
apertures and having the room illumination remain 
const1ant throughout the testing so as not to aff'ect 
the reading. All subjects were optometry students 
having their best subjective Rx in place during 
the testing. The accommodative and convergence 
; 
responses under forced and free posture conditions 
were'then determined by the following testing 
pro'cedures. The order of testing used is as 
follows: 1. near monocular cross cylinder (14A); 
2. near binocular cross cylinder through 15 prism 
diopters base; 3. near binocular cross cylinder (14B); 
-4-
4. near binocular cross cylinder through 12 prism 
diopters base out; 5. near binocular cross cylinder 
(14B); 6. near phoria through best subjective 
Rx combined with -1. 00 D; 7. near phoria through 
best subjective Rx combined with plano; 8. near 
phoria through best subjective Rx combined with +l.00 
diopters; and 9. near phoria through best subjective 
Rx combined with +2.00 diopters. All near testing 
was done at 16 inches. The first.five procedures 
were implemented using a �0.50 diopter flip cylinder 
and a diagonal cross grid target. The subject 
was then asked to report which set of lines were 
darkest when he looked through the best subjective 
Rx combined with +3.00 diopters. Plus sphere 
·was then reduced until the opposite set of lines 
were reported as darkest. The phoria testing 
procedures were accomplished using a dissociating 
prism in front of the left eye and measuring 
prism in front of the right eye, with the subject 
viewing a reduced Snellen card. 
After the pre-testing, two drops of 0.1% 
Cyclogyl were administered to each eye. Then 
at 10 minute intervals, the 9 testing procedures 
and a pupil measurement were re-run. Four 
consecutive 10 minute intervals were used. 
-5-
' -
The v.1% Cyclogyl solution was prepared by 
using nine parts of standard Soflens saline 
solution and one part 1% Cyclogyl. A u.1% 
Cyclogyl solution is not normally available from 
pharmaceutical houses but usually is obtained in 
0.5%, 1%, or 2% solutions. 
-6-
RESULTS and DISCUSSION 
The eleven subjects were tj.ivided into three 
groups according to their convergence and accom­
modative postures as demonstrated by the pre-testirig 
procedures. The subjects of Group I were considered 
to be on the norm of the general population; they 
were slightly exophoric at near, orthophoric to 
six prism diopters, and their accommodation was 
about 0.75 diopters behind the plane. Group II 
consisted of subjects with large esophoria at 
near; six prism diopters and above, and about 
2.00 diopters of accommodative response with the 
free posture test. Group III subjects were all 
greater than two prism diopters esophoric and 
averaged seven prism diopters of esophoria. The 
accommodation averaged, in that group, 1.50 
diopters behind the plane. 
Discussion of the nphoria v. s. time graph 11 
groups shall be first. One can readily see the 
shift toward the esophoric position was very rapid 
after the instillation of the drug, the peak effect 
being noticed at twenty minutes. _From the twenty 
to forty minute interval, there was very little 
change in the phoria. This was probably due to 
-7-
L 
the fact that the system reached its end point. 
The average change in the phoria toward esophoria 
was approximately 16 prism diopters over the 
forty minute period. In other words, the phoria 
had changed 80% of its total change by the end 
of the first twenty minutes. 
"Accommodative response .v.s. time0 is the 
second group that shall be discussed. As the 
graphs clearly show, for all groups there was· 
a gradual decrease in accommodative response to 
an almost negligible amount at thirty minutes; 
this was not expected to occur with the diluted 
solution used. With the increased convergence 
stimulus of 12 prism diopters B. 0., the accom­
modative response was the greatest throughout the 
testing; but it also showed the greatest reduction 
in response. The 14A response differed by less 
than a .12 diopter for the subject's two eyes, 
but this was considered to be clinically insignif­
icant. �mmediately after instillation of the drug, 
the 14B combined with 15 prism diopters E.T. for 
Groups I and II demonstrated a 1.00 diopter 
accommodative response while Group I II had very 
little accommodative response. With the full 
-8-
•. 
effect of the drug, all groups showed no accom­
modative response with their convergence set at 
infinity. 
Even though all three groups started out 
with different accommodative response; they all 
ended with essentially no accommodation, and all 
had the same relationship between the various 
testing procedures. 
"AC/A v.s. time" is the third group that will 
be discussed. The two curves of the AC/A ratio 
on these graphs were determined with two different 
stimulus ranges. For one curve, of the Ac/A v. s. 
time, the determinations were made by having the 
near Snellen chart at sixteen feet and then recording 
phoria values with a lens range of plane to -1.00 
D. through time. The second curve was plotted 
by using the same method but having a lens range 
of +1. 00 D. to -1 . 00 D. 
For all graphs in each group, the AC/A 
ration change reached a maximum value at twenty 
minutes. The curve that reached the highest 
maximum value for each group was the AC/A deter­
mination made by the one diopter lens range. The 
two diopter lens range AC/A ratio determination 
showed the least maximum increase with time. 
-9-
This least maximum increase is probably due to 
blur created by the mydriasis from the action 
of the Cyclogyl. The accommodative response 
change was not directly proportional to the 
range of stimulus change. Since a proportional 
accommodative change did not occur, a subsequent 
change in convergence due to accommodation could 
not take place. The values of the two diopter 
lens range AC/A ratio determination were reduced 
as compared to the one diopter lens ·range deter­
mination. The two diopter stimulus range mostly 
decreased the blur of the target as plus lens 
were added. To a small degree, this changed the 
AC/A ratio dictated by the accommodative response. 
Quantitatively, Group II showed the largest 
change with time. The one diopter lens range 
curve showed.a change from 4 prism diopters to 
11 prism diopters. For the two diopter lens range, 
the AC/A· change was from 4 prism diopters exo 
to 8 prism diopters. For the one diopter lens 
range, the change ranged from 7 prism diopters 
to 12 prism diopters. The two diopter lens 
range had a small change of 7 prism diopters 
to 8 prism diopters. For Group I, the two 
curves were close to the same. The AC/A 
change ranged from 4 prism diopters to 8 prism 
diopters. 
- 10 -
Ave.rage for all subjects 
l 
Age 26 
Iris Pigment 3 
0 Time 
Pupil size 5. 75mm 
14A +1.06 
ll+B/ 15B. I. +1.59 
14B + .95 
14B/12B.O. + .32 
14 B + .82 
P/-1.00 3 eso 
p 2 exo 
P/+l.00 7 exo 
P/+2.00 10 exo 
Average f-or Group I 
Age� 
Iris Pigment 2.9 
Pupil size 5.9mm 
14A +l.08 
14B/15B.I. +1.50 
14B + .75 
14B/12B.O. 0 
14B + • 50 
P/-1.00 3 eso 
p 2 exo 
P/+l.00 6 exo 
P/+2.00 9 exo 
10 min. 
6.63mm 
+1.59 
+1.88 
+1.38 
+1.18 
+1.34 
15 eso 
12 eso 
2 eso 
6 exo 
6.25mm 
+l.33 
+1.91 
+1.41 
+l.40 
+l.00 
15 eso 
10 eso 
3 exo 
3 exo 
-11-
20 min. 30 min. 40 min . 
.7. 77rrun 8.47mm 8.88mm 
+1.86 +2 . 09 +2.15 
+2.11 +2.18 +2.36 
+l.<32 +2.00 +2.02 
+1.63 +1.84 +l.93 
+1.82 +2.04 +2 . 09 
20 eso 21 eso 22 eso 
16 eso 19 eso 19 eso 
12 eso 14 eso 14 eso 
2 exo 2 eso 0 
7.3mm 8.5mm 9.166rnm 
+1.75 +1.91 +2.00 
+2.16 +2.25 +2.33 
+1.75 +1.91 +2.00 
+1.50 +1.66 +1 . 83 
+2.2 +1.9 +2 . 00 
19 eso 20 eso 21 eso 
15 eso 17 eso 17 eso 
10 eso 9 eso 10 eso 
0 2 exo 0 
Average for Group I I  
Age 25 
Iris Pigment 3 
() Time 
Pupil size 5.9mm 
14A +1.12 
14B/15B.I. +1.35 
l4B + .65 
14B/12B.O. 0 
14B + .50 
P/-1.00 3 exo 
p 8 exo 
P/+l.00 11 exo 
P/+2.00 15 exo 
Average for Group III 
Age--2._ 
Iris Pigment__.3 __ _ 
Pupil size 5.33mm 
14A +l.33 
14B/15B.I. +2.08 
14B +1.66 
14B;l2B.O. +l.00 
14B +i.66 
P/-1.00 13 eso 
p 7 eso 
P/+l.00 3 exo 
P/+2.00 5 exo 
lO·min. 
7.omm 
+1.4 
+1.65 
+1.10 
+ • SU 
+1.40 
11 eso 
7 eso 
4 exo 
10 exo 
6.4mm 
+2.00 
+2.33 
+1.83 
+1.58 
+1.90 
23 eso 
21 eso 
9 eso 
1 exo 
-12-
20 min. .. , 30 min. 40 min.i 
7.9mm 8.3mm 8.55mm 
+l.70 +2.15· +2�15 
+1.90 +2.00 +2.30 
+1.80 +2.00 +1.9 
+l.50 +1.90 +1.95 
+1.70 +2.00 +1.90 
17 eso 19 eso 20 eso 
13 eso 17 eso 16 eso 
6 eso 13 eso 12 eso 
6.4 exo 1 eso 2 exo 
8.0mm 8.75mm 9.16mm 
+2.16 +2.16 +2.33 
+2.4 +2.416 +2.41 
+2.08 +2.08 +2.25 
+1.90 +l.90 +2.00 
+1.66 +2.20 +2.33 
27 eso 26 eso. 27 eso 
22 eso 23 eso 26 eso 
21 eso 20 eso 22 eso 
5 eso 8 eso 4 eso 
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SilliTiv1AR Y 
When this project originated, the authors 
established their purpose to be that of showing 
the interaction of the accommodative and conver­
gence systems. This was hoped to be achieved 
by instilling a diluted normal concentration of 
the drug Cyclogyl. As can be noted, the accommodative 
system was affected to the degree that we would 
expect with the normal concentrated solution. 
By inhibiting the accommodative system to this 
degree, one cannot ascertain a great deal about 
the interaction. As is also noted, the AC/A 
ratios increased a great deal with the peak being 
at twenty minutes. 
The authors of this paper suggest that in 
future study, a more diluted drug be used. By 
doing this, one could find the concentration 
that would inhibit the accommodative system to 
a small degree so that the interaction could be· 
studied in greater depth. The possibility of 
a more diluted drug used for the purpose of 
visual training would also be interesting as 
further study in this area of drug use. 
-25-


Results of a partial cycloplegic on the visual system

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Results of a partial cycloplegic on the visual system

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