HOW TO INTERPRATE PENTACAM IMAGE AND ITS WORKING?

1. PENTACAM
SIMI AFROZ
Assistant Professor
Department of optometry
School of Medical and Allied Health Sciences
G D GOENKA UNIVERSITY
B.Optom (A.I.I.M.S.), M.Optom (Amity University)

2. What is pentacam?
 A comprehensive diagnostic tool that image the entire anterior
segment and present data in an easy and interpretable form.
 Contain rotating scheimpflug camera which capture 50 images in 2
seconds.
 It provides a 3 -D virtual model of anterior eye segment (from
anterior surface of cornea to posterior surface of lens).
 2 camera:-
 One to scan the eye
 Other to monitor the fixation

3. Principle
 Normal camera:
film plane║lense plane║image plane
 Scheimpflug principle: lens plane
intersects the film plane, the plane of
sharp focus must also pass through
that same line.

4. Applications
 Corneal ectasia
 Refractive surgery
 Corrected IOP
 Corneal aberrations
 IOL power calculation
 Densitometry

5. Corneal ectasia and refractive
surgery
 Qs
 Kmax
 Thinnest pachymetry
 Topographical astigmatism
 Maps (curvature, pachymetry, anterior and posterior elevation)
 Belin ambrosio enhanced ectasia display
 Inter eye corneal symmetry

6. Curvature map
Symmetric shape- 50D, difference 2.5D
Asymmetric shape- 47D, difference 1.5D

7. Pachymetry map
 Measure thickness from
limbus to limbus.
 At centre of pupil.
 At the apex of cone.
 At the thinnest point.
 Relative pachymetry map
 Corneal volume.

8. Anterior and posterior elevation
map
Steep areas are
below the
reference
surface(red)
flat areas are above the
reference surface (blue)

10. Astigmatism vs. Keratoconus

11. Belin - ambrosio enhanced ectasia
display
 Df(deviation of front elevation)
 Db( deviation of back elevation)
 Dp( deviation of average
pachemetry progression)
 Dt( deviation of minimum
thickness)
 Da( deviation of ART Max)
Normal cornea

12. Before & After Exclusion Software

13. Patient details

14. Rules of thumb
 Highest curvature point and the thinnest point on pachymetry
coincides.
 The highest curvature point coincides with the highest anterior and
posterior elevation points.
 Highest curvature point, thinnest point and anterior and posterior
elevation point all coincides to confirm the diagnosis of ectasia.

15. Patient details

16. Patient details

17. Patient details

19. Patient details

20. Patient details

21. IOL power calculation
 EKR: equivalent keratometry reading.
 Lens thickness
 IOL Formulas
Placido based topographers have blind
spot in the centre.
Ratio of radius of curvature b/w front and
back of cornea is 82% and constant
Post refractive surgery patient coming
with cataract
For myopic ratio decreases
For hyperopic ratio increases

24. Corneal aberrations
➢ Based on Zernike analysis

26. SIMI AFROZ
Assistant Professor (ADHOC)
Department of optometry
School of Allied Health Sciences and Research
SHARDA UNIVERSITY
B.Optom (A.I.I.M.S.), M.Optom (Amity University)
simi.afroz@sharda.ac.in