Glaucoma New Zealand

- A Charitable Trust

Glaucoma New ZealandAims to

• eliminate blindness and visual disability from glaucoma in our community

• inform and educate people about how best to live with glaucoma

Glaucoma in General Practice

The aim of this initiative is to:

• Compare the presentation of glaucoma and cataract in General Practice

• Address detection of glaucoma by optic disc assessment.

• Review the “Risk Factors” for glaucoma• Clarify the role of health and life-style issues

in patients with glaucoma.

A Common Clinical EncounterThis is a true patient scenario..

Visual loss from .....

A Christchurch CASE :

A 81 yr old man is referred by his GP for urgent cataract surgery for his very poor vision.

He was having visual difficulties coping with living alone and was concerned about his driving.

He thought that charity or public hospital cataract surgery would be the answer...

Past eye history

Five years earlier an eye specialist diagnosed ocular hypertension and started timolol eye drops. The patient completed the dispensed medication then stopped treatment.No follow up occurred.

The referring GP enclosed a copy of the reply letter from the eye specialist when the patient was seen five years earlier. It gave the above detailed history.

Ocular examination in 2008...

The best corrected visual acuity was:Right : 6 / 24 Left : 6 / 9

The intra-ocular pressure was:Right : 40 mm Hg Left : 40 mm Hg

The optic discs were both markedly cupped:cup / disc ratios Right 0.9+ Left 0.9

There was extensive visual field loss (see later)

There were early lens opacities present in both eyes as is common in this age group

Left Visual Field Right Visual Field

Humphrey visual fields in this patient

Humphrey Visual Fields

• The patients visual field is a “blackout” !• There is minimal response centrally in the

left visual field. But none in the right field. The mean deviation of loss is over 25 decibel in each eye.

• The blackout doesn’t mean he is totally blind but that the highest intensity of light for the machine has been reached. And he still cannot see it

• Whatever, it is disastrous for the patient !

Implications for this man...

Primary open angle glaucoma is the main threat to this man’s eyesight, his independence and his driving licence.

Most of his sight loss cannot be restored.

Treatment of his ocular hypertension for five years would have prevented this situation.

A further delay of a few months would have been disastrous for him with intra-ocular pressures at 40 mm Hg and with markedly cupped optic discs.

Implications

A priority appointment should be given for this patient, if the referral letter states :

• Visual acuity does not improve with a Pin Hole• Raised intra-ocular pressure.• Markedly cupped optic discs• Visual field defects• You suspect glaucoma• None of these factors were noted.Preventing treatable blindness is an order of

priority higher than restoring sight from cataract, which can be done at anytime.

Outcome

This patient fortunately received an early appointment because he went privately despite limited means and no insurance.

Initial glaucoma treatment was commenced and he had investigations and follow up in public.

He will not be able to return to driving. Which means you and your loved ones may live longer !

Comparison ofCATARACT and GLAUCOMA

Cataract and glaucoma compared

CATARACT• The patient will present to you when the visual

disability reaches the threshold for that person to complain about their vision.

• “Screening” for cataract is not required. • Visual acuity with a pinhole is near normal for

early to modest cataract (and refractive errors)• Vision can be restored by surgery at any stage

in the development of cataract from a clear lens to one that has been dense for years.

Cataract and glaucoma compared

GLAUCOMA• The patient will complain of visual problems

only at a late stage in glaucoma development.• The sight lost cannot be restored (this century!)• The cupped optic disc is at high risk for sudden

loss of vision from a retinal vein occlusion, which adds insult to the injury !

• Early treatment is effective in preventing progression in glaucoma damage.(Level 1 evidence: multiple double blind trials)

Glaucoma in General Practice

THREE considerations for today:• Detecting glaucoma : symptomatic and

asymptomatic patients.• Assessment of “Glaucoma Risk Factors” :

determines appropriate monitoring and may indicate pre-glaucoma intervention. (reviewed)

• Evaluation of health and life-style issues that may accelerate damage to the cupped and compromised optic disc in those with glaucoma.

Detecting Glaucoma

In Patients with symptoms

and

In Patients without symptoms(everyone !)

In patients with symptoms:

Blurred vision, gradual visual loss, etc• Do Pinhole VA. If No improvement be

concerned for serious eye pathology (not cataract or refractive errors). But a good PH VA does NOT exclude severe glaucoma.

• Assess risk factors for glaucoma. (see review)• Assess the optic disc. (see below)• Consider assessment of the visual field

(to be discussed in the next GNZ presentation)

In patients with symptoms:

Painful inflamed eye : consider angle closure• Assess risk factors (see review)

Age, Asian, Hypermetropia, Family history• Ask about halos around lights (corneal oedema)• The pupil may be mid-dilated

(if small, the diagnosis is more likely to be iritis)• The intra-ocular pressure will be very high and

must be measured. • The optic disc will be normal except in chronic

angle closure when it will be cupped.

In people without symptoms :

Asymptomatic presentation occurs most often:• Early to moderately severe glaucoma usually

presents without symptoms !• Check Glaucoma out when the opportunity

arises.

• The “Routine General Check up”Anyone requesting a “routine check up” is asking“What will kill me, what will harm me, doctor ?”Firstly cancer, secondly blindness, is the public’s concern in many surveys.

That means glaucoma !

The first Glaucoma NZ Powerpoint presentation for General Practitioners gave an overview of glaucoma in your practice. It addressed “Risk Factors”. See it on www.glaucoma.org.nz

This presentation mainly focuses on the optic disc in glaucoma.

We acknowledge that the skill of ophthalmoscopy cannot be taught here. But we note that new types of ophthalmoscope are available to help the non- specialist to view the optic disc.

Optic Disc Assessment

Ophthalmoscopy• Direct viewing is most convenient for you.

Indirect viewing uses a slit lamp microscope.• Documentation of the optic disc:

Draw the disc and its cupAssess the vertical ratio of the cup diameter to the disc diameter. Record as a decimal eg 0.3

Optic disc scanning : a technical assessmentGDx, OCT, HRT machines. They will become widely used in the next few years.

Optic Disc Parameters to check

• Optic disc size and shape. Larger discs have larger cups ! There is more room for the same number (1.2 million) of nerve fibres.

• Optic shape is similar in both eyes in most people. The exception is highly myopic eyes.

• Neuro-retinal rim: The ISNT rule is that it is thickest Inferiorly, reducing Superiorly, Nasally then Temporally in the normal disc.

• Disc margin haemorrhage (an important sign)• Peripapillary atrophy

The Neuro-retinal rim / nerve fibres

GENERALISED LOSS• Assess the cup / disc ratio esp. vertically.• Assess the thickness of the rim to the cup.• A normal cup is oval horizontally.• The glaucomatous cup is often oval vertically.• The mean c /d ratio is 0.3 with a wide range !• Your index of suspicion will be enhanced if you see a

large c / d ratio. (As in the patient described.)• Asymmetry in the c / d ratio between eyes is very

significant. (< 0.2 difference in 98 %)

The Neuro-retinal rim / nerve fibres

LOCALISED LOSS• Look for localised notches in the rim.• Focal loss is often inferiorly, then superiorly.• Record as the c / d ratio in that meridian

eg. c/d 0.9 at 5 o’clock

PALE DISCS• Glaucomatous discs may look pale as the cup

deepens and enlarges. BUT..• True pallor of the rim ( the remaining nerve fibres) is

optic atrophy NOT glaucoma.

Typical cortical cataract shadows in the red reflex.Expect good Pin hole acuity here or consider dual pathology

Fundus photo of the same eye. Blurred view from cataract but optic disc visible : healthy disc with cup / disc ratio of 0.3

The optic disc in glaucoma

• Glaucoma is defined by progressive cupping of the disc.

• A single observation of the discs may alter your management of your patient.

• You will assess all risk factors that you can, and determine an appropriate course of action.

• You may seek a full eye examination where otherwise no action may have been taken.

• You may write “suspicious of glaucoma” which will generate a priority response !!

The optic disc in glaucoma

The following table outlines a range of optic disc for comparison with your patient.

The image can be downloaded from the GP Arena on www.glaucoma.org.nz

Your optic disc findings should be considered along with the clinical presentation and your assessment of the “Risk Factors” for glaucoma.

Asymptomatic patients with NO risk factors, refer:OD c / d ratio of > 0.8OD notch, haemorrhage, or asymmetry.

An evidence based guide does Not exist

“Optic Nerve Head Signsin Glaucoma”, is kindly providedby Dr Allan Simpson of Christchurch.

The file is attached for you to print and use for comparisonwith the optic discs you see inyour patients !

The vertical cup to disc ratio isan assessment of the diameterof the cup as a ratio of the disc.It is given as a decimal.0.1 is a very small cup ; healthy !1.0 means there is no neuro retinalrim remaining. Its too late !

SUMMARY

• You are in the best position to prevent glaucoma blindness in your patients.

• Glaucoma is progressive cupping of the optic disc which you may be able to detect at least when the cupping is severe.

• Patients may be harmed when visual blur is put as cataract. A non urgent priority may be given..

• Glaucoma should be considered in other patient presentations and especially when patients request a “Routine general check up”

Please Promote Glaucoma Awareness

Glaucoma Risk Factors Reviewed

Risk Factors for Open Angle Glaucoma

Identified without an eye examination

• Age

• Family history

• High myopia

• Previous eye trauma

• Steroid use

Risk Factors for Open Angle Glaucoma

Identified by an eye examination

• Intra-ocular pressure

• Central corneal thickness

• Optic disc structure

• Intra-ocular pathology

Pseudo-exfoliation. Pigment dispersion

Vascular and inflammatory disease

Congenital abnormalities

Risk Factors for Angle Closure Glaucoma

• Age

• Family history

• Hypermetropia (long sightedness)

• Anterior chamber (AC) morphology

Shallow AC, narrow AC angles

• Race : Asian

The gold standard : “45 plus 5”

Glaucoma NZ recommends that every adult have an eye examination at age 45 years and every 5 years there-after.

Individuals with significant risk factors detected by examination require more frequent assessment.

By aged 80 yrs, many will need 2 yearly examination.

The General Practitioner and Glaucoma Awareness

Promote the “45 + 5” glaucoma eye test

Identify glaucoma risk factors for greater attention

Incorporate Glaucoma Awareness and screening recommendations into every day practice.

Health and life-style issues in the patient with glaucoma

Health and life-style issues in the patient with glaucoma

Diabetes mellitus, hypertension and vascular disease

• Primary glaucoma is not more frequent here.• Routine Glaucoma Eye Examinations should

be done according to the standard recommendation above, in these patients.

• However the cupped disc may be at risk if there is high, low or fluctuating blood pressure.

• Treat these conditions gently !• Stable good control is recommended.

Health and life-style issues in the patient with glaucoma

Vascular spasm eg migraine, Raynaud’s • Routine Glaucoma Eye Examinations should

be done according to the standard recommendation above.

• Vascular spasm is implicated in glaucoma progression in “Normal Tension Glaucoma” where non-pressure factors appear to play a significant role in cupping the optic disc.

• Stable good control is recommended.

Health and life-style issues in the patient with glaucoma

Special life-style issues (theoretical)• Short term IOP fluctuations maybe harmful :

Head down Yoga positions, Valsalva manoeuvres e.g. playing wind instruments

• Situations with low pO2 : e.g. prolonged high altitude, climbers, glider pilots

Patients with marked glaucoma damage may need to modify some life-style choices.

Glaucoma in your General Practice

A successful outcome of this initiative would be:• You thinking “Glaucoma” when your patient

complains of blurred vision etc.• You assessing the optic disc for marked cupping

by ophthalmoscopy in your patients to identify a need for urgent referral.

• You appreciating the known risk factors or markers, for developing glaucoma, that call for greater attention than in the normal population.

• You considering the effect on optic disc perfusion when managing your patient’s general health.

General Practice and Glaucoma NZ

Glaucoma New Zealand welcomes general practitioner involvement in our mission to “eliminate glaucoma blindness from our community”.

Glaucoma NZ provides a “Professional Education Package” on-line that presents ten glaucoma cases with questions, answers and discussion.You are welcome to register for it.

Glaucoma New Zealand welcomes your feedback on this presentation.

Public education about glaucoma

Glaucoma New Zealand provides information to the public who enrol with us. There is no fee.

We publish “Eyelights” a regular newsletter, maintain a web site, and produce additional educational materials. See www.glaucoma.org.nz

Please encourage your patients with glaucoma to enrol with us.

Glaucoma New Zealand wishes to thank our sponsors

without whose help we could not

undertake our activities

General Practice and Glaucoma NZ

You can support our cause by:• Donations • Sponsorship• Involvement in our activities in your area.• Promoting bequests to Glaucoma

Glaucoma New Zealand thanks you for your time and consideration with this presentation

Glaucoma New Zealand

Department of Ophthalmology

The University of Auckland

Private Bag 92019

Auckland

Tel 09 373 8779

Fax 09 373 7947

www.glaucoma.org.nz

Email: info@glaucoma.org.nz