Pachymetry is used to measure corneal thickness using various methods. It plays an important role in glaucoma diagnosis and refractive surgery planning by providing measurements of central and peripheral corneal thickness. Abnormal pachymetry readings can indicate conditions like glaucoma, through correlation with increased intraocular pressure, or keratoconus, seen as major corneal thinning on imaging. Both ultrasonic and optical devices exist to perform pachymetry, utilizing contact or non-contact methods, with newer technologies like Pentacam and Pachycam using Scheimpflug imaging principles for quick, portable corneal thickness evaluation.

1. PACHYMETER
Presented by
Anuska Chakraborty Shreya Dan Halima Khatun

2. What is Pachymetry?
Greek word:
Pachos = thick & metry = to measure

3. Pachymeter measures Corneal Thickness
Peripheral CT : 0.7 – 0.9 mm
Central CT : 0.49 – 0.56 mm
Normal CT : 540 – 560 micron
CCT depends upon some factors
CORNEAL PACHYMETRY

4. Role of
Pachymetry Glaucoma
Refractive Surgery
Pathophysiology

5. Aware of
outcomes
Patient
sorting
LASIK Laser-assisted in situ Keratomileusis

6. Indicator
of rise
IOP
Corneal
thinning
Glaucoma

7. Abnormal
imaging
Major
corneal
thinning
Keratoconus

8. PACHYMETER

9. Ultrasonic Optical
Alternative
Measurements
1. Ultrasonic
Pachymetry
3. Manual 10. Pentacam
2. Ultrasound
Biomicroscopy
4. Specular Microscopy 11. Pachycam
5. Scanning Slit
Technology
12. Ocular Response
Analyzer
6. Optical Coherence
Tomography
7. Optical Low Coherence
Interferometry
8. Confocal Microscopy
9. Laser Doppler
Interferometry

10. ULTRASONIC
PACHYMETER
~~~~>
<~~~
Probe
Handle
Transducer
Tip
Comp
onent
s

11. CT+AS+PS
thickness
evaluation
Faster
Easy to use Portable
Consistent Intraoperative
Contact
method
Probe
handling
Low
resolution
Problematic
for abnormal
cornea

12. ULTRASOUND
BIOMICROSCOPE

13. CT+AS
thickness
evaluation
Useful for
opaque
cornea
Examine
corneal
layers
Sometimes need
cupping
Contact
method
Supine
position
Not
intraoperative
Difficult to
standardize

14. SPECULAR
MICROSCOPE
Monitor
Classification
Contact
Non contact

15. Operator
independent
CT+ Corneal
layer
examination
Not accurate
Time
consuming
Non
inoperative
Not useful
for abnormal
cornea

16. Methods
Just
touch
Overlap
MANUAL
PACHYMETER

17. SCANNING SLIT
TECHNOLOGY

18. AS - OCT
Reference
mirror
Photo detector

19. OPTICAL LOW COHERENCE
REFLECTOMETER

20. CONFOCAL
MICROSCOPE
Types
Tandem
scanning
CM
Scanning
slit CM
Laser
scanning
Microscope

21. LASER DOPPLER
INTERFEROMETER

22. PENTACAM
Scheimpflug
principal

23. PACHYCAM
The first compact and portable non-
contact pachymeter with built-in
keratometer.
Here the pachymetry is based on
Scheimpflug images of a horizontal 4mm
cut and provides immediate indication of
the central & thinnest corneal thickness.

24. OCULAR RESPONSE
ANALYZER