1. GLAUCOMA UPDATE Managing The Glaucoma Suspect – When Do I Refer?
DR RAJIV SHAH
EASTWOOD EYE SURGERY

2. Glaucoma
Glaucoma is the most common cause of irreversible blindness worldwide
Often bilateral and mostly asymptomatic
Early detection and intervention will reduce incidence of blindness and visual morbidity
Well established risk factors, clinical findings, investigations and treatments

3. Glaucoma Suspect Many people are labelled as Glaucoma Supects (GS)
Usually those with borderline IOP, family history or questionable disc/field changes
Aren’t enough eye doctors in the community to see them all
The optometrist is often the carer for the GS
Patients have faith in their healthcare providers and therefore we need to know how to manage and when to refer (this applies for all)

4. Glaucoma Suspects
Is it acceptable to follow up GS with serial white on white fields?
Once a field defect is seen many nerve fibres have been lost (Klein et al.,IOVS 2004; 45:59-62)
Ideally, in the 21st century we need to aim to detect damage at preperimetric levels
Not always easy – compliance and cost issues, keeping up with technology
There are some simple and effective ways

5. Who to screen? Everyone? Those with family history? Raised pressure?
Those above 40?
All of the above
It doesn’t take a long time to look at a disc even through an undilated pupil

7. Key Questions
The optometrist is often the first port of call. Role as the eye GP?
Family history – blindness, laser/surgeries, eyedrops, glaucoma or ocular hypertension?
Isn’t always reliable
Disregard beyond two generations and beyond first cousins/ blood uncles and aunts

8. Key Questions Past ocular history? Previous trauma
Previous LASIK / other laser surgery (PI/ALT), other incisional surgery and complications
Eyedrops
Refraction, amblyopia

9. Key Questions General Health Asthma Hypertension Diabetes Sleep Apnea
Migraine
Neurological problems (CVA, tumour) – can cause field defects
Medications – antidepressants, sulphonamides, steroids (inhaled, nasal, topical, systemic)

10. Key Questions Other risk factors Age Racial group Consanguinity
Occupation
Driving
Cigarettes / alcohol
Living arrangements / carers

11. Examination Aided and unaided VA RAPD CCT
IOP (Goldmann applanation). Diurnal?
AC depth (Van Herrick > ¼ cornea thickness). Gonioscopy ?
Iris heterochromia, PXF, PDS
Look for laser iridotomy, iridoplasty, PS, Glaukomflecken, cataract (phacomorphic)
DILATE (very, very small risk of AAC)

12. CCT
Central corneal thickness (CCT) measurements must be performed in all glaucoma suspects. Those with thinner corneas (<500 microns) have a greater risk of glaucoma development and progression (OHTS Study).
MUST BE CENTRAL!

13. Phacomorphic Glaucoma

14. IOP
Which method?
NCT
Applanation
Tonopen
Percussion
Artifacts – lid pressure, breath holding, upgaze, lash, blepharospasm, too much fluorescein, astigmatism, corneal scar, nystagmus
At what level is treatment mandatory?

15. IOP
There are a large percentage (30% at least) of patients who have glaucoma with normal pressures (NPG). In some populations (Japan, Korea) NPG incidence is 2-3 times POAG.
The end organ damage is the same (disc cupping) but the natural history and prognosis may differ. There is a stronger association with vascular disorders ( migraine, nocturnal hypotension, Raynauds disease)

16. Ocular Hypertension Ocular hypertension when IOP > 21mmHg
The most significant risk factor for glaucoma development
Different techniques/examiners can get differing IOP
OHTS looked at people with IOP 24-32
Probability of progression in the treated group (4.4%) was half that of observation group (9.5%) at 5 years
90% didn’t progress at 5 years
Role of corneal thickness

17. Does lowering IOP help? No evidence until late 1990’s
Early Manifest Glaucoma Trial (EMGT)
Compared immediate treatment v no or delayed treatment on newly diagnosed POAG patients
Treated group had less frequent and later progression at 6 years
High IOP risk of vascular occlusions

18. Examination Disc size – must identify the limits of the disc C/D
Notching? General rim thinning? ISNT rule
PPA?
Pallor? Colour?
Disc haem?
RNFL defects
Other disease – lid height, ARMD, DR, peripheral retina abnormalities, RP, Laser scars, disc drusen, tilted discs, disc pits
THESE CAN CAUSE FIELD DEFECTS

19. FORGE : 5 Rules of disc assessment (Focusing Ophthalmology on Reframing Glaucoma Evaluation)

20. Disc Size (Fingeret et al, Optometry 2005)

21. Disc Anomalies (Fingeret et al)

22. ISNT Rule and NFLD (Fingeret et al)

23. PPA
Alpha and beta
Alpha in most normals – hyper and hypopigmetation of RPE
Beta more in glaucomas – atrophy of RPE and choriocapillaris
Alpha more peripheral if both present
Extent of beta corresponds with extent of rim loss

24. PPA (Fingeret at al)

25. Investigations
Disc photography (stereo?) – simple, cheap and very effective. Give patient a copy!
Field (SAP, FDT, SWAP ) - subjective, time consuming, late diagnosis
OCT / HRT / GDx – expensive, useful for progression?

26. Visual Fields Patients hate fields (nearly as much as puff tonometry)
Many differing machines and strategies
Get familiar with your machine, its limitations and the artifacts that come up
Know how to do your own fields or delegate to someone trained in them
Explain and instruct the test to patients (will not see every spot, may be gaps)

27. Visual Fields
Don’t set the patient up and then leave, get coffee, make phone calls.
Quiet and dark room
Let patients know that they can stop and restart. Make sure they are comfortable
Let them know that all doesn’t depend on one field test (may need 3 or 4 before a pattern is identified. A learning effect will be seen)
If they are tired, sleepy, not well or anxious then do it another day

28. Visual Fields Is it reliable? (correct patient, age, refraction, eye)
Test duration?
Is it reproducible?
Does it match the disc?
Does it look like glaucoma? Follow NFL pattern?
Make sure you are comparing tests of the same strategy (SITA Fast v Standard, 24-2 v 10-2 or 30-2)
Look for artifacts- lid, lens rim, pupil size, cataract

29. Artifacts

30. Lid Artifact

31. Fell Asleep?

32. Glaucoma?

33. The other eye….

34. Where is the lesion?

35. OCT in Glaucoma Most recent addition in disc and RNFL imaging
Many now using it to image the disc and RNFL
RNFL loss often precedes cupping
Will detect damage before SAP (or FDT- Brusini P, Eye 2007 Feb)
How useful is/will it be to detect change in the RNFL thickness ?

36. Fast RNFL Analysis
Three 3.4mm diameter circle scans in 1.92 secs allow all retinal nerve fibres to be imaged
Fast RNFL Thickness Protocol
3 consecutive circular scans in single 1.92 sec session
256 axial determinations per circle
measured along a nominal 1.73 mm radius circle on the peripapillary RNFL
The thickness at each test point determined by averaging the three measurements
‘Regular” RNFL Thickness Protocol
3 separate circular scans (3*1.28 secs = 3.84 secs total)
Each single scan consisting of 512 A-scans
Zafar et al J. Glaucoma 2004;13(2) no statistical difference in RNFL between test strategies in normals or glaucoma patients
Acquires 768 A-scans 3* 256 A-scans per circular scan

37. Ocular Hypertension

38. Moderate glaucoma (MD -9.06)

39. Optic Nerve Stress