Tonometry PPT

2. Definition :-
It is the procedure
performed to dtermine
the intrapocular pressure
(IOP)

3. Def. of Glaucoma
It is the characteristic
and progressive condition of
the eye which is raised the
intraocular pressure occurs
progerssivly damage the
optic nerve due to loss of
vision.

4. Direct Indirect
Manometer
DIGITAL INDETATION
(Schiotz)
APPLANATION
(Goldman)
NCT
Types of Tonometer
Perkin’s

5. Indentation tonometer
(Schiotz)
Principle:-
- Amount of the indentation
depends upon IOP
-The higher IOP the lesser
IOP
-The lesser theIOP the deeper
the indentation

6. -Less reading on scale ---- High
IOP
-Scale reading have to be converted
to IOP by the help of chart
(Friedenwald conversion table)
HENCE

7. Plunger of tonometer
Indenting the cornea
Base plate of
tonometer resting on
cornea
Fig.1 In this cornea is indented

8. PART OF SCHIOTZ TONOMETER
scale
Needle
Weight 5.5g
plunge
r
Holder
Foot plate
lever
3mm diameter
Additional weights
7.5,10,15g
Pseudocornea

9. Process :-
-Patient in supine position
- 4%lignocaine
-looking up at a fixation target
Advantage:-
- Fast
- Very good to camp screening
- Portable
- Cheep
- Easy to cleaning & mantainance
- No required Slit lamp / electricity

10. Disadvantage :-
- Reading effect by corneo scleral
regidity
- Can not be done in injury cases/early
post-op
Cleaning& Mantanance:-
- Cleaning after the removed from barrel
with
> Alcohal
> Methylated spirt

11. Calibration:-
This instrument should be
calibrated before each use by placing
on seudo cornea and be sure checking
scale reading is zero.

12. Applanation tonometer
Principle:-
-Applanation tonometer based
on IMBERT FICK LAW
- Biprism tip flattens
- A Biprism convert applantion
area into half alingnment of 2 half give the
correct IOP reading
- Applanates a small area of
cornea central 3.06mm.

13. F- Force
A- Flatening ofthe area
P- Pressure in side the Eye
IMBERT FICK LAW

14. Parts of Applanation tonometer
Biprism
(measuring
prism)
Feeder arm
Housing
Adjusting knob
Connects to the slit
lamp
Control weight insert

15. Equipment:-
-Housing control the prism movement
-Neck
-Biprism plastic Biprism with a mirror to
slit corneal applantion image to 2 halfs

16. Process:-
-slit lamp
-4% xylocaine
-Dark room
- Flurosceine stain of tear film
-Cobalt blue light
-Biprism applanation cornea with
knobs reading at (1)
-Reading read on knobs scale
multiplied by 10 ====IOP

17. Advantage:–
- Most accurate .
-No indentation so not
much force applied on cornea.
-Does not effect by cornea
scleral rigidity .
-Reading directly read from
knob .
-Can be done on post op case
/injury cases .

18. Disadvantage :-
-Need slit lamp .
-Dark room .
- Need staining cobalt light .

19. Calibration:-
 Appl, tonometer is calibrated with calibration
bar.
 it should be done once in a weekly or monthly

20. NON CONTACT TONOMETER
Principle :-
A puff of air creates a
constant force that momentarily
flattens the cornea and internal
reference point to the movement
of flattening is measured and
converted to IOP .

22. ADVANTAGE ;-
-Quick .
-No anesthetic required .
-May be delegated .
-Nothing contact to the Eye .

23. DISADVANTAGE :-
-Expensive .
-Difficult on to obtain reading on scarred
cornea , soft Eye .
-Not partable .
.

24. Perkins Tonometer
 It uses the same biprism as the Goldmann applanator.
 The light source is powered by battery.
 The readings are consistent and compare quite well
with the Goldmann applanator.