A method and apparatus is described for safely reducing abnormally high intraocular pressure in an eye during a predetermined time interval. This allows maintenance of normal intraocular pressure during glaucoma surgery. A pressure regulator of the spring-biassed diaphragm type is provided with additional bias by a column of liquid. The hypodermic needle can be safely inserted into the anterior chamber of the eye. Liquid is then bled out of the column to reduce the bias on the diaphragm of the pressure regulator and, consequently, the output pressure of the regulator. This lowering pressure of the regulator also occurs in the eye by means of a small second bleed path provided between the pressure regulator and the hypodermic needle

Baehr, E. F.

English

NASA Technical Reports Server

United States Patent [19] [111 4,157,718 
Baehr [45] Jun. 12, 1979 
[54] INTR&OCULAR PRESSURE 
NORMALIZATION TECHNIQUE AND 
EQUIPMENT 
[75] Inventor: Edward F. Baehr, Berea, Ohio 
[73] Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
[21] Appl. No.: 829,318 
[22] Filed: Aug. 31, 1977 
[51] Int. C l . 2  ......................... A61M 1/00; A61M 5/14 
[52] US. c1. .................................................... 128/276 
[58] Field of Search .................... 128/2.05 G, 2.05 D, 
128/276,2 T, 213, 215,216,227, 172, 350 R, 
350 V 
1561 References Cited 
U.S. PATENT DOCUMENTS 
3,185,153 5/1965 Leucci ......................... 128DIG. 13 
3,572,319 3/1971 Bittner et al. ........................ 128/213 
3,931,818 1/1976 Goldowsky .......................... 128/227 
4,078,563 3/1978 Tuseth .................................. 128/227 
4,084,612 4/1978 Baehr ................................ 137/484.2 
Primary Examiner-Robert W. Michell 
Assistant Examiner-J. Kruter 
I 
Attorney, Agent, or Finn-Norman T. Musial; John R. 
Manning; James A, Mackin 
[571 ABSTRACT 
There is disclosed a method and apparatus for safely 
reducing abnortnally high intra-ocular pressure in an 
eye during a predetermined time interval. This allows 
maintenance of normal intraocular pressure during 
glaucoma surgery. According to the invention, a pres- 
sure regulator of the spring-biassed diaphragm type is 
provided with additional bias by a column of liquid. 
The height of the column of liquid is selected such that 
the pressure at a hypodermic needle connected to the 
output of the pressure regulator is equal to the measured 
pressure of the eye. The hypodermic needle can then be 
safely inserted into the anterior chamber of the eye. 
Liquid is then bled but of the column to reduce the bias 
on the diaphragm of the pressure regulator and, conse- 
quently, the output pressure of the regulator. This low- 
ering pressure of the regulator also occurs in the eye by 
means of a small second bleed path provided between 
the pressure regulator and the hypodermic needle. Al- 
ternately, a second hypodermic needle may be inserted 
into the eye to provide a controlled leak-off path for 
excessive pressure and clouded fluid from the anterior 
chamber. 
11 claipls, 2 Drawing Figures 
I 
r 
25 
https://ntrs.nasa.gov/search.jsp?R=19800006426 2020-03-21T02:03:19+00:00Z
U.S. Patent Jun. 12, 1979 Sheet I of 2 4,157,718 
P 
25 
FIG. I 
U.S. Patent Jun. 12,1979 Sheet 2 of 2 4,157,718 
22 
4,157,718 
2 
DESCRIPTION OF A PREFERRED 
EMBODIMENT 
Referring now to FIG. 1 there is shown apparatus 
5 including a pressure regulator 10, a filter 11, a reservoir 
12 and a vertical tube 13. A buffered saline solution 14 
or treatment fluid flows from reservoir 12 through a 
conduit 15 and into ftlter 11. The fluid then flows out of 
the bottom of filter 11 and through a passageway 16 into 
10 an inlet chamber 17 of the pressure regulator 10. From 
inlet chamber 17 the fluid flows through a diaphragm 
controlled valve which is shown and described in FIG. 
2 and out of an outlet port 18 through reflexible tube 19 
INTRA-OCULAR PRESSUlRE NORMALIZATION 
TECHNIQUE AND EQUIPMENT 
ORIGIN O F  THE INVENTION 
m i s  invention was made by an employee of the U.S. 
Government and may be or used by or 
for the Government of the United States without the 
payment of any royalties thereon or therefor. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention to ophthalmic surgery and is and the hypodermic needle 20 into the interior chamber 
directed more particularly to a method and apparatus 15 of an eye 21. 
for reducing intraocular Pressure Prior to surgery and 
for maintaining normal pressure during surgery. 
This will be explained more fully with regard to FIG. 
2. A suitable fluid such as distilled water disposed in 
2. Prior Art vertical tube 13 or standpipe increases the pressure of 
Glaucoma is a disease of the eye involving abnor- the fluid at outlet port 18. In order to gradually reduce 
mally elevated intraocular pressure. Such pressure can 20 the pressure at outlet port 18, the fluid level into 13 is 
cause irreparable damage to the eye and eventual blind- rduced by bleeding-fffluid by means Of a small length 
ness. In the event that surgery is required on the eye, the Of tubing 22 which COm~~unicates with the bottom of 
intraocular pressure must be reduced to a safe level. tube 13* The diameter and length Of tube 22 determine 
Any attempt to penetrate the eye surgically while the the tube 22 may be termed a 
pressure is markedly elevated involves a high risk of Pressure regulator 10 is a one-way device in that fluid 
hypodermic needle 20 is inserted into the anterior rapid pressure loss. 
In the past, prior to opthaldc sWFrY9 intramular chamber of eye 21, there is no flow-path for fluid which 
Pressure has been reduced by the administration Of 30 is to be removed from the eye. To provide such a path, 
drugs Or the use of other systemic n ~ a n s .  Such Proce- a tube 23 communicates with tube 19 at some point 
dures often require a time-period of several hours or between outlet 18 and hypodermic needle 20. The 
more to obtain the desired reduction in intraocular pres- length and inside diameter of tube 23 must be selected to 
sure. Additionally, drugs may have undesirable side obtain the flow rate desired. Tube 23 thus serves as a 
effects on some people and/or may be insufficiently 35 pressure relief bleed means. 
effective on others. As an alternate pressure relief bleed path, particularly 
under conditions where the anterior chamber contains 
OBJECTS AND SUMMARY OF THE clouded fluid, a second hypodermic needle 24 may be 
INVENTION inserted into the anterior chamber of the eye 21 and a 
It is an object of the invention to provide a method 40 tube 25 connected thereto cames away the fluid. As in 
the case of tube 22, the diameter and length of tube 25 and apparatus for controllably and safely reducing in- determine the rate of removal of fluid from the anterior 
chamber of the eye. Tube 25 and hypodermic needle 24 traocular pressure in an eye. 
It is another object of the invention to provide a comprise an irrigation bleed means. 
method and apparatus for cOntrouably reducing the 45 Referring now to FIG. 2, there is shown an oblique 
Pressure in an eye to a Predetermined safe value and cutaway view of the essential parts of pressure regula- 
then maintaining the Pressure constant during a dau- tor 19. Parts corresponding to those of FIG. 1 are iden- 
coma surgery. tified by like numerals. Pressure regulator 10 includes a 
Still another object of the invention is to provide a valve 26, a diaphragm 27 supported on a backing plate 
method and apparatus for reducing and controlling the 50 28, and a bias spring 29. Spring 29 exerts pressure 
pressure of liquid supplied to an eye and for removing against backing plate 28 to open valve 26. Fluid, as 
fluid from the eye at a controlled rate. indicated by arrows 25, flows through the valve 26 
In su-ary, the invention provides a method and against the underside of diaphragm 27 and through 
apparatus for controllably and safely reducing intraocu- Outlet port l8 into tube 19- The of spring 
lar pressure in an eye by providing means for biasing a 55 29 determines the pressure of the fluid at outlet port 18. 
pressure regulator connected between a source of treat- components just described are well known in the prior art and are much like any 
rate and* 
25 bias bleed means. 
to the eye* This damage is a Of can flow only out of outlet 18. Consequently, when 
The pressure 
merit fluid and a hypodermic 
the eye such that the Pressure at the 
to be inserted into standard diaphragm type pressure regulating device. 
However, a preferred pressure regulating device is the is equal to that measured for the eye. After the needle is 6o flow 
inserted into the eye, the bias is then reduced in a prede- 
termined manner. 
pressure regulator disclosed and 
in the copending application of Edward F. 
Baehr, Ser. No. 779,428, filed Mar. 21, 1977, now US. 
Pat. NO. 4,084,612 and assigned to the assignee of the 
instant invention. 
As shown in FIG. 2, an adjuster 30 is provided to 
change the compression of spring 29 so that the pressure 
at outlet port 18 may be adjusted to a desired value. An 
aperture 31 is provided in adjuster 30 so that fluid in 
BRIEF DESCRIPTION OF THE DRAWINGS 
FIG. 1 is a pictorial diagram of apparatus utilized 65 
FIG. 2 is an oblique sectional view of the pressure 
with the invention. 
regulator portion of FIG. 1. 
4,157,7 1 8 
3 4 
vertical tube 13 may flow through the adjuster and past 
the spring 29 to the upper side of diaphragm 27 and 
through a bleed-off outlet port 32 into the tube 22. The 
pressure of the fluid adds to the bias of spring 29 to 
increase the pressure at outlet port 18. Thus, the height 
indicate actual pressure at outlet 18 for any particular 
fluid level in standpipe 13. The pressure regulator 10 is pressure at outlet 18 is equal to the measured intraocular 
adjusted to a pressure of from 15-25 mm of mercury but pressure. 
According to the inventive method, the intraocular 10 a nominal pressure of 20 mm ofmercury has been found 
pressure of an eye diseased by glaucoma, for example, is to be satisfactory. 
measured. A reservoir such as 12 containing a treatment It will be understood that changes and modifications 
of fluid 14 is provided and connected to a tube such as may be made to the above-described method and appa- 
15 and 19 to the hypodermic needle 20. The reservoir 12 ratus by those skilled in the art without departing from 
is raised to a height such that the fluid pressure at the tip l5 the Spirit and scope Of the invention as set forth in the 
of hypodermic needle 20 is equal to that measured in the 
eye as, for example, 60 mm of mercury. Hypodermic 
needle 20 is then inserted into the anterior chamber of 
the eye and the reservoir is gradually lowered until the 20 
pressure at the tip of the hypodermic needle is approxi- 
mately that of a nOrma1 eye, for example, 20 mm of 
mercury. At the same time, some pressure is bled off 
through a pressure relief bleed. 
lator such as 10 which, after the initial pressure reduc- 
tion, will maintain pressure constant at the hypodermic 
needle 20. 
13 is filled with suitable fluid (distilled water) to a level 
such that pressure at hypodermic needle 20 is equal to 
that measured in the eye. After the hypodermic needle 
20 is inserted into the anterior chamber of the eye, the 
bias bleed orifice, tube 22, bleeds-off fluid from the 35 
vertical tube 13 causing the pressure at hypodermic 
needle 20 to decrease from a hieh mamitude as. for 
TABLE I-continued 
Length Inside Diameter 
18”-78”(39”) 0.03 1”-0.062”(0.03 1”) 
5 
of the fluid in tube 13 can be adjusted such that the As shown in 1, l3 is calibrated to 
appended hereto* 
I 
1. Apparatus for ophthalmic surgery comprising: 
a pressure regulator of the spring-biased diaphgram 
type having an inlet, an outlet and a diaphragm 
having an upper side and a lower side; 
a supply of treatment fluid connected to said inlet of 
said pressure regulator; 
a first hypodermic needle connected to said outlet of 
said pressure regulator; 
a generally vertical bias fluid tube having a lower end 
communicating with the upper side of said dia- 
phragm of said pressure regulator; 
a bias bleed means communicating with the upper 
side of said diaphragm of said pressure 
for bleeding fluid from said vertical tube to reduce 
the pressure at said outlet at a predetermined rate; 
and 
pressure relief means providing an outflow path for 
fluid from said hypodermic needle. 
2. The apparatus of claim 1 wherein said bias bleed 
means is a tube of Predetermined length and inside di- 
Preferably the fluid 14 is directed to a pressure regu- 25 
Utilizing the pressure regulator 10, the vertical tube 30 
- I 
example, 60 mm of mercury, to a normal level as, for 
example, 20 mm of mercury. The pressure relief bleed wherein said tube has a 
40 length of from about 30 cm to 100 cm and an inside 23 relieves some of the pressure at outlet port 18 and, 
consequently, at hypodermic needle 20. After the pres- 4. The apparatus of wherein said tube is about 
sure of the eye is reduced to a normal level, surgical of about 1.5 cm. 
procedures can be initiated. 5. The apparatus of claim 1 wherein said pressure 
Preferably, the flow compensating regulator of the 45 relief means is a tube of predetermined length and diam- 
previously identified copending patent application eter communicating with said first hypodermic needle. 
would be used. This pressure regulator includes means 6. The apparatus of claim 5 wherein said tube is about 
for controlling output pressure despite variations in the 50 cm 10% and has an inside diameter of about 0.75 mm. 
flow rate of fluid to the eye during operative proce- 7. The apparatus of claim 6 wherein said tube is about 
dures. 50 208 cm long and has an inside diameter of about 1.5 mm. 
relief means comprises a second hypodermic needle the apparatus are given below in Table I with preferred communicating with a tube of predetermined length 
and inside diameter. dimensions in parenthesis. 
TABLE I 9. The apparatus of claim 8 wherein said tube has a 
length of from about 50 cm to 200 cm and an inside 
diameter of from about 0.75 mm to 1.5 mm. 
10. The apparatus of claim 9 wherein said tube is 
about 100 cm long and has an inside diameter of about 
Tube 23 50-200cm (l00cm) 0.75mm-1.5mm (0.75mm) 11. The apparatus of claim 1 wherein said pressure 
ameter- 
3’ The apparatus Of claim 
diameter of from about 0.75 mm to 1.5 mm. 
38 cm long and has an -de 
n e  range of dimensions of various components of 8. The apparatus of claim 1 wherein said pressure 
55 
Length Inside Diameter 
Standpipe 13 70-80cm (74 cm) 1.27-2.5cm (2.24cm) 
Tube 22 30-100cm (38cm) 0.75mm-1.5mm (1.5mm) 
27.5-31.5”(29”) 0.5-l.O”(O.875”) 
12”-39”( 14.9”) 0.031”-0.062”(0.062”) 60 0*75 
18”-78”(39”) 0.03 1”-0.062”(0.03 1“) regulator is of the flow compensating type. * * * * *  Tube 25 50-200mm (l00cm) 0.75mm-1.5mm (0.75mm) 
65 


Intra-ocular pressure normalization technique and equipment

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server