This document discusses using optical coherence tomography (OCT) to analyze the macula, retinal nerve fiber layer (RNFL), and optic nerve head in patients with glaucoma or suspected glaucoma. It describes how OCT can measure macular thickness, RNFL thickness, and optic disc parameters. Five case studies are presented showing how structural changes seen on OCT correlate with functional defects on visual field tests or clinical findings. The document concludes by mentioning Doppler OCT may help understand the role of blood flow in glaucoma and other optic neuropathies.
3. OCT Software analyses-
Macula Thickness
Retinal Nerve Fibre Layer (RNFL)
Optic Nerve Head (ONH)
4. Macula Thickness Analysis
Ganglion cells- 30-35% of total retinal thickness at macula
upto 50%of ganglion cells in macula
glaucoma preferentially involves the ganglion cell complex (GCC).
Normal
Glaucoma with thinner GCC
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6. RNFL analysis
Circular scanning
around ONH at a radius
of 1. 73mm
Three scans are acquired
and data is averaged and
compared with
normative data base of
age matched subjects
Scan begins temporally
7. RNFL thickness average analysis printout -7
zones
Zone -1-Pt. I.D
Zone -2-TSNIT with age matched normative data base
Zone-3-TSNIT overlap of two eyes
Zone -4-circular scan-quadrant/clockwise
Zone-5-DATA TABLE-ratio/average
Zone-6-RED FREE PHOTOGRAPH-position
Zone-7-PERCENTILE COLOR CODING
9. Optic nerve head analysis
Optic nerve head scans are
composed of six linear
scans in a spoke pattern
separated by 30-degree
intervals centered on the
ONH
10. Cup/disk ratios and cup Volumes
Disc size:
by measuring the distance
between the terminal ends of
the choriod at the level of the
pigment epithelium (green
line)
Cup:
determined by drawing a line
b/w both sides of the cup at a
point 140um above the green
line.
Area below the line is cup and
above is neuroretinal rim
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12. Case 1-(Structure Function Correlation)
56 year old female with open angle glaucoma
NFL lesion at inferior pole of ONH
Superior defect in perimetry
Thinning of RNFL in OCT
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16. Case 2 (early glaucoma)
59 year old male with suspicious optic nerve
Normal perimetry
Normal IOP
No positive family history
Thinning of NRR clinically
Nasal step in SWAP
RNFL thinning in OCT
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23. Case 3-(Unilateral Open Angle Glaucoma)
54 year old female
Unilateral exfoliative glaucoma
IOP- 33 mmHg
Thinning of NRR in sup, inf and temporal
Inferior arcuate defect in perimetry
RNFL thinning in sup and inf pole in OCT
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27. Case 4-Glaucoma suspect
62 year old female
Large C:D ratio
B/L with positive family history
Normal IOP
Normal achromatic and FDP
Normal RNFL and large disc area and increased C:D
ratio on OCT
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32. Case 5 (Ocular Hypertension)
Suspicious optic nerve head
Perimetry normal
Borderline FDP
Borderline thickness values with more thinning at
superior and inferior pole on OCT
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38. DOPPLER OCT(F-Domain)
Retinal blood flow measurement with Doppler OCT may help
us understand the role of perfusion in the causation and treatment
of glaucoma, other optic neuropathies and retinal diseases