Presentation on theme: "GLAUCOMA UPDATE Managing The Glaucoma Suspect – When Do I Refer?"— Presentation transcript:
1 GLAUCOMA UPDATE Managing The Glaucoma Suspect – When Do I Refer? DR RAJIV SHAHEASTWOOD EYE SURGERY
2 GlaucomaGlaucoma is the most common cause of irreversible blindness worldwideOften bilateral and mostly asymptomaticEarly detection and intervention will reduce incidence of blindness and visual morbidityWell 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 changesAren’t enough eye doctors in the community to see them allThe optometrist is often the carer for the GSPatients 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 SuspectsIs 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 levelsNot always easy – compliance and cost issues, keeping up with technologyThere are some simple and effective ways
5 Who to screen? Everyone? Those with family history? Raised pressure? Those above 40?All of the aboveIt doesn’t take a long time to look at a disc even through an undilated pupil
7 Key QuestionsThe 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 reliableDisregard 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 complicationsEyedropsRefraction, amblyopia
9 Key Questions General Health Asthma Hypertension Diabetes Sleep Apnea MigraineNeurological problems (CVA, tumour) – can cause field defectsMedications – antidepressants, sulphonamides, steroids (inhaled, nasal, topical, systemic)
10 Key Questions Other risk factors Age Racial group Consanguinity OccupationDrivingCigarettes / alcoholLiving 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, PDSLook for laser iridotomy, iridoplasty, PS, Glaukomflecken, cataract (phacomorphic)DILATE (very, very small risk of AAC)
12 CCTCentral 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!
14 IOPWhich method?NCTApplanationTonopenPercussionArtifacts – lid pressure, breath holding, upgaze, lash, blepharospasm, too much fluorescein, astigmatism, corneal scar, nystagmusAt what level is treatment mandatory?
15 IOPThere 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 developmentDifferent techniques/examiners can get differing IOPOHTS looked at people with IOP 24-32Probability of progression in the treated group (4.4%) was half that of observation group (9.5%) at 5 years90% didn’t progress at 5 yearsRole 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 patientsTreated group had less frequent and later progression at 6 yearsHigh IOP risk of vascular occlusions
18 Examination Disc size – must identify the limits of the disc C/D Notching? General rim thinning? ISNT rulePPA?Pallor? Colour?Disc haem?RNFL defectsOther disease – lid height, ARMD, DR, peripheral retina abnormalities, RP, Laser scars, disc drusen, tilted discs, disc pitsTHESE CAN CAUSE FIELD DEFECTS
19 FORGE : 5 Rules of disc assessment (Focusing Ophthalmology on Reframing Glaucoma Evaluation)
23 PPAAlpha and betaAlpha in most normals – hyper and hypopigmetation of RPEBeta more in glaucomas – atrophy of RPE and choriocapillarisAlpha more peripheral if both presentExtent of beta corresponds with extent of rim loss
25 InvestigationsDisc photography (stereo?) – simple, cheap and very effective. Give patient a copy!Field (SAP, FDT, SWAP ) - subjective, time consuming, late diagnosisOCT / HRT / GDx – expensive, useful for progression?
26 Visual Fields Patients hate fields (nearly as much as puff tonometry) Many differing machines and strategiesGet familiar with your machine, its limitations and the artifacts that come upKnow how to do your own fields or delegate to someone trained in themExplain and instruct the test to patients (will not see every spot, may be gaps)
27 Visual FieldsDon’t set the patient up and then leave, get coffee, make phone calls.Quiet and dark roomLet patients know that they can stop and restart. Make sure they are comfortableLet 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
35 OCT in Glaucoma Most recent addition in disc and RNFL imaging Many now using it to image the disc and RNFLRNFL loss often precedes cuppingWill 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 AnalysisThree 3.4mm diameter circle scans in 1.92 secs allow all retinal nerve fibres to be imagedFast RNFL Thickness Protocol3 consecutive circular scans in single 1.92 sec session256 axial determinations per circlemeasured along a nominal 1.73 mm radius circle on the peripapillary RNFLThe thickness at each test point determined by averaging the three measurements‘Regular” RNFL Thickness Protocol3 separate circular scans (3*1.28 secs = 3.84 secs total)Each single scan consisting of 512 A-scansZafar et al J. Glaucoma 2004;13(2) no statistical difference in RNFL between test strategies in normals or glaucoma patientsAcquires 768 A-scans 3* 256 A-scans per circular scan