1. David B Henson Medical School University of Manchester
MSc Investigative Ophthalmology & Vision Sciences Visual field defects in glaucoma
David B Henson
Medical School
University of Manchester

2. Classification of glaucoma
Primary 95%
Secondary 5%
Closed angle
33%
Open angle
66%
Congenital 1%

3. Definition of POAG
Progressive optic neuropathy with characteristic changes at the optic nerve head and to the visual field.
Associated with a raised IOP

4. Detecting glaucoma Based on 3 measures IOP ONH evaluation
Visual fields

5. Types of visual field loss
Nerve fibre bundle defects
Paracentreal
Arcuate
Nasal step
Site of lesion
Overall depression
Enlargement of the blind spot

6. Paracentral/Arcuate defects
Follow nerve fibre distribution
More common in superior hemifield
Abrupt discontinuity at horiz midline

7. Involvement of the macular
OCT of macular from
case with early glaucoma
Thickness of nerve fibre layer complex. Note how inferior region is thinner
Probability plot- highlights
regions outside normal
Comparison to normal
Hood D et al IOVS 2014;55:633-

8. Involvement of macular: OCT plus VF
10-2 visual field.
Position of stimuli adjusted to match RGC displacement
OCT of macular
Defect in superior VF and inferior macular

9. Involvement of macular: OCT and VF
Probability plot
Early glaucomatous defect. Very few 24-2 points involved

10. Nasal Step
Due to sensitivity difference above and below the horizontal midline
Small steps are not uncommon in ‘normals’ (>5 degrees significant)
Highly specific
Predominantly found with kinetic strategy

11. Overall depression Due to diffuse loss of nerve fibres Common 38%
About 1-2dB
Not specific to glaucoma
Could be due to cataract
Contributes little to diagnosis

12. Enlargement of the Blind spot
Not specific to glaucoma
Large range of ‘normal’ sizes
Cannot detect small increases in size with current static techniques
Linked to peripapillary atrophy (PPA)

14. Henson DB et al. Invest Ophthal Vis Sci 2000;41:417-421.

15. Variability Difficult to diagnose Normal Suspect Defect intermittent
3.5 years
(1-6 years)
Normal
Suspect
Defect
3 consecutive
normal
fields
3 consecutive
abnormal
fields
Also add:
Variability is first sign of glaucoma
Heijl A, Bengtsson B (1996) Glaucoma: Decision Making in Therapy. Ed. Bulli, Springer

16. When did this patient develop a VF defect in the RE?
How does this relate to the definition of glaucoma?

17. Factors that affect Variability
Stimulus size, decreases with larger stimuli
Increases towards periphery
Related to lower sensitivity in periphery
Increases when you test sparse populations of retinal ganglion cells, e.g. blue on yellow
Not only found in glaucoma, same with other pathologies
Test algorithm, extended test algorithms tend to give more accurate threshold estimates but take longer (SITA Std vs SITA fast)
Patient vigilance

18. William Burley, Global grad PD –1.473
Patient WB

19. Patient TS

20. Evolution of glaucoma defects
Earliest sign is an increase in the scatter of results
Defects might be intermittent
Early sign is an asymmetry between the two eyes
Develops into a permanent defect, paracentral.
Develops into an arcuate
Develops into a hemifield loss

21. Asymmetry

22. Asymmetry

23. Is this glaucoma?

24. Conclusions Defects Follow distribution of nerve fibres
Asymmetric between eyes and between hemispheres
Variable
Patient dependent
Intermittent