Newer modalities in diagnosis of glaucoma

1. Newer modalities in
diagnosis of Glaucoma
Bipin Bista
Resident
Ophthalmology
National medical College
& Teaching Hospital

2. Imaging technologies for evaluation of
Glaucomatous damage
• Digital imaging is indispensable in providing objective and reproducible
measurements of the optic nerve head and retinal nerve fiber layer for
detection and monitoring of glaucoma.
• Confocal Scanning Laser Ophthalmoscopy (CSLO), Scanning Laser
Polarimetry (SLP), Optical Coherence Tomography (OCT)

3. CSLO

4. COMPARISON
• CSLO : Only OD parameters (NR rim area, cup area, Cup-Disc area).
• SLP : Circumpapillary RNFL thickness.
• OCT : Measurement of RNFL, OD parameters, inner macular thickness.
 All the imaging technologies have had significant improvements in the
hardware and software configuration over past decade.

5. Latest generations/High generation
• CSLO : Heidelberg Retina Tomograph (HRT); Heidelberg Engineering,
GmbH, Heidelberg, Germany
• GDx ECC (enhanced corneal compensation; Carl Zeiss Meditec, Dublin,
California)
• Spectral-domain or Fourier-domain OCT

6. GDx ECC-Enhanced corneal compensation

7. Spectral-domain or Fourier-domain OCT

8. Spectral-domain or Fourier-domain OCT

9. Detection of Glaucomatous Damage
• Glaucomatous Optic Disc Damage is characterised by progressive narrowing
of the neuroretinal rim , cupping of the OD, and thinning of RNFL.
• For measurement of the neuroretinal rim area in CSLO, a reference plane
(located 50µm below the mean retinal surface outlined by a manually drawn
contour line at the disc margin between 350 & 356 degrees) is adopted to
delineate the neuroretinal rim (above the reference plane) and OD (below the
reference plane).
• Detection of RNFL alone is not alone.

10. Detection of Glaucoma Progression
• Requires trend-based or event based analyses.
• Commercially available algorithms for analysis include the Topographic
Change Analysis (TCA) in the HRT (Heidelberg Engineeing) and the Guided
Progression Analysis (GPA) in the GDx VCC/ECC (Carl Zeiss Meditec) and
Cirrus HD-OCT (Carl Zeiss Meditec).

11. Summary
• In theory, SLP may detect RNFL damage earlier than does OCT since
disruption of the axonal microtubules may precede loss of the nerve fiber
bundles in glaucoma.

12. 24 hour measurement of IOP
• Triggerfish contact lens system
(Sensimed AG, Lausanne,
Switzerland)

13. Reference:
1.Glaucoma – Shield Textbook of Glaucoma 6th edition
2.Curbside Consultation in Glaucoma : Steven J. Gedde
3.Myron yanoff and jay s duker4th edition
THANK YOU