Glaucoma

Question 1

What causes glaucoma?

Answer 1

Blockage of aqueous humour drainage into the canal of Schlemm, resulting in increased intraocular pressure

Glaucomas are optic neuropathies associated with raised intraocular pressure (IOP)

Question 2

In open-angle glaucoma, what is the position of the iris relative to the trabecular meshwork?

Answer 2

The iris is clear of the meshwork.The trabecular network functionally offers an increased resistance to aqueous outflow, causing increased IOP.

The trabecular network offers increased resistance to aqueous outflow, causing increased IOP.

Question 3

What is aqueous humour produced by?

Answer 3

the ciliary body and drains into the trabecular mesh work, between, the cornea and iris into the canal of schlem.

Question 4

What is the normal range for intraocular pressure?

Answer 4

10-21 mmHg from resistance to flow in the trabecular mesh work.

This range is determined by resistance to flow in the trabecular meshwork.

Question 5

What is the primary function of the optic disc?

Answer 5

Exit point for the
* optic nerve
* central retinal vein

entry point for the
*central retinal artery to transmit visual signals from the eye to the brain.

It creates a ‘blind spot’ in vision due to the absence of photoreceptors.

Question 6

Why is there a blind spot in vision?

Answer 6

Since there are no photoreceptors (rods and cones) at the optic disc, it creates a “blind spot” in our vision, but the brain compensates for this so we don’t typically perceive it

Question 7

What does cupping of the optic disc indicate?

Answer 7

Enlargement of the normal central depression, indicating damage to the optic nerve fibers From glaucoma.

This causing the “cup” to appear larger relative to the surrounding “disc”

A ratio greater than 0.5 indicates glaucoma.

Question 8

What is the normal cup-to-disc ratio?

Answer 8

0.4-0.7

Question 9

What ratio indicates glaucoma?

Answer 9

ratio greater than 0.7 as loss of disc substance makes optic cup widen and deepen

Question 10

List the risk factors for open-angle glaucoma.

Answer 10

• Elderly
• Family history
• Black ethnicity
• Myopia
• Hypertension
• Corticosteroid use
• Diabetes mellitus

These factors increase the likelihood of developing open-angle glaucoma.

Question 11

What are common symptoms of open-angle glaucoma?

Answer 11

• Typically asymptomatic
• Gradual loss of peripheral vision
• nasal scoot a progressing to tunnel vision
• Fluctuating pain
• Halos around light worse at night

Symptoms may be incidental findings during an optometrist visit.

Question 12

What findings are observed during fundoscopy in open-angle glaucoma?

Answer 12

• Optic disc cupping (cup-to-disc ratio >0.7)
• Optic disc pallor
• Bayonetting of vessels
• Cup notching inferior to where the vessels enter the disc
• Disc haemorrhages

These findings indicate changes in the optic nerve health.

Question 13

Why does optic disc pallor occur?

Answer 13

indicates optic disc atrophy

Question 14

Why does bayoneting of the vessels occur in open angle glaucoma?

Answer 14

vessels have breaks as they disappear into the deep cup and re-appear at the base

Question 15

What to do if patient presents with Open angle glaucoma in GP?

Answer 15

Patients should be referred to ophthalmologist via GP.

Case finding and provisional findings are done by optometrists.

Question 16

What is the role of an optometrist?

Answer 16

An optometrist provides primary eye care, including routine exams, vision tests, and treating common eye conditions and refractive errors.

Question 17

Differentiate between open-angle glaucoma and acute anterior uveitis.

Answer 17

• Open-angle glaucoma: Gradual loss of peripheral vision
• Acute anterior uveitis: Red, painful eye, blurred vision, photophobia

Each condition presents with distinct symptoms and requires different management.

Question 18

What is the role of an ophthalmologist?

Answer 18

An ophthalmologist is a medical doctor (MD) who specializes in surgical and medical eye care, capable of diagnosing and treating all eye diseases and performing eye surgery

Question 19

What are the investigations for open angle glaucoma?

Answer 19

• automated perimetry to assess visual field
• slit lamp examination
• applanation tonometry
• central corneal thickness measurement
• gonioscopy

Question 20

Which examiantion measures IOP?

Answer 20

Applanation tonometry by measuring corneal response to puff of air.

High intra-ocular pressure will have little response to introduction of air.

​

Question 21

Which examiantion measures anterior chamber depth?

Answer 21

gonioscopy to assess peripheral anterior chamber configuration and depth

Question 22

What is the role of slit lamp examiantion?

Answer 22

Done when eye is in pupil dilatation to assess optic nerve and fundus for a baseline

Question 23

How to determine future risk of visual impairment with glaucoma?

Answer 23

Using risk factors such as IOP, central corneal thickness (CCT), family history, life expectancy_

Question 24

What is the gold standard investigation for glaucoma?

Answer 24

Goldman applanation tonometry, that makes contact with cornea and applies pressure to obtain direct readings for intra-ocular pressure.

Question 25

When to treat patient with raised IOP in glaucoma?

Answer 25

Start treatment at intraocular pressure of 24mmHg minimum

Question 26

What is the **first line treatment** for clinically raised intraocular pressure?

Answer 26

360-degree laser trabeculoplasty ## Footnote Further treatment may be needed based on patient response.

Question 27

What is the **gold standard** for measuring intraocular pressure?

Answer 27

Goldman applanation tonometry ## Footnote This method involves contact with the cornea to obtain direct readings.

Question 28

What is second line treatment for glaucoma?

Answer 28

Use of prostaglandin analogue latanosporst to increase uveoscleral outflow. It is a Once daily administration

Question 29

What are the adverse effects of latanosprost?

Answer 29

brown pigmentation of the iris, increased eyelash length

Question 30

What is the **third line treatment** for glaucoma?

Answer 30

* Topical beta blocker (timolol) * Carbonic anhydrase inhibitor (dorzolamide) * Sympathomimetic (brimonidine) * Miotics (pilocarpine) ## Footnote These treatments aim to inhibit aqueous humour production or increase outflow.

Question 31

When to avoid beta blocker in glaucoma?

Answer 31

asthmatics Patients with heart bloc

Question 32

What is a risk of use of carbonic and rate inhibitors?

Answer 32

Carbonic anhydrase inhibtior dorzolamide to inhibt aqueous humour production. Systemic absorption may cause sulphonamide-like reactions, such as Steven’s-Johnson syndrome.

Question 33

Which pharmacological treatment can be given to increase uveoscleral outflow?

Answer 33

Miotics can be used like pilocarpine, a muscarinic receptor agonist to increase uveoscleral outflow.

Question 34

What are the adverse effects of miotics?

Answer 34

Adverse effects included a constricted pupil, headache and blurred vision ​

Question 35

What does trabeculecomy involve?

Answer 35

create a new channel under the conjunctiva to create a new pathway for aqueous humour drainage.

Question 36

What is **acute angle glaucoma**?

Answer 36

An ophthalmological emergency with blockage to the trabecular meshwork, resulting in increase in anterior chamber and presses on the iris. ## Footnote This condition results in increased anterior chamber pressure and can lead to optic nerve damage.

Question 37

What is primary angle closure?

Answer 37

Primary angle closure is the term used to describe when the iris blocks the drainage angle but there is no evidence of optic nerve damage

Question 38

List the **clinical presentations** of acute angle glaucoma.

Answer 38

* Severe painful red eye * Halo around light * Blurred vision * Headache, nausea, vomiting It can come on while watching TV in a dark room due to pupillary dilation. ## Footnote Patients may appear systemically unwell.

Question 39

What are the risk factors for ancute angle closure?

Answer 39

* female * East Asian * elderly due to lens growth with age * family history * hyperopia and short axial length of eyeball * shallow anterior chamber * pupillary dilation either iatrogenically or being in a dimly lit environment

Question 40

What are the drugs that can induce acute anglue closure glaucoma?

Answer 40

Topical mydriasis Systemic alpha adrenergic agonists which cause pupillary dilation Adrenergic medication Anticholinergic like oxybutynin and solifenacin Tricyclic antidepressant like amitryptilline

Question 41

What will physical examiantion show for closed angle glaucoma?

Answer 41

* Hazy cornea that has corneal oedema * Red, teary eye * Reduced visual acuity * Closed iridocorneal angle on gonioscopy * Pupil will be mid-dilated or dilated and fixed * Eyeball is firm and hard on palpation * Intraocular pressure above 21mmHg

Question 42

What investigation is key for closed angle glaucoma?

Answer 42

gionioscopy, which exams the drainage angle between the iris and cornea. In acute angle closed glaucoma, there will be closed iridoconreal angle.

Question 43

What is the **initial management** for acute angle glaucoma?

Answer 43

Refer for same-day assessment by ophthalmology While in GP awaiting for ambulance, lie patient on back, give pilocarpine eye drop, 500mg oral acetazolamide and analgesia and antiemetic. ## Footnote While waiting, administer pilocarpine eye drops and acetazolamide.

Question 44

What is the dose of pilocarpine for patients with brown eyes?

Answer 44

4%

Question 45

What is the dose of pilocarpine for patients with blue eyes?

Answer 45

2%

Question 46

What is the **definitive treatment** for acute angle glaucoma?

Answer 46

Peripheral laser iridotomy ;to create hole in iris and allow aqueous humour to flow from posterior into anterior chamber. the contralateral eye is treated prophylactically as it is predisposed to PACG ## Footnote This procedure creates a hole in the iris to allow aqueous humour to flow.

Question 47

What to give in hospital while awaiting definitive treatment?

Answer 47

combintion of IOP lowering agents like: pilocarpine, Acetazolamide, Timolol and dorsolamide to reduce aqueous humour production

Question 48

What to give 2nd line if no improvement with intial IOP lowering agents?

Answer 48

rarely Hyperosmotoic agent like glycerol or mannitol can be given intravenously to increase osmotic gradient and reduce intraocular pressure

Question 49

Differentiate between **open-angle glaucoma** and **acute anterior uveitis**.

Answer 49

* Open-angle glaucoma: Gradual loss of peripheral vision * Acute anterior uveitis: Red, painful eye, blurred vision, photophobia ## Footnote Each condition presents with distinct symptoms and requires different management.

Question 50

Differentiate between **close-angle glaucoma** and **sudden retinal detachment**.

Answer 50

presentation is Sudden appearance of floaters, flashes of light in the periphery, and a shadow or curtain over a portion of the visual field.

Question 51

How do visual field defects present in open angle glaucoma?

Answer 51

insidious onset of peripheral vision loss and a loss of visual acuity, indicative of optic nerve atrophy secondary to chronically increased intraocular pressure (IOP)

Question 52

What are the pupil findings for acute angle closure glaucoma?

Answer 52

the pupils are usually mid-dilated and non-reactive This is due to blockage of the anterior chamber angle by the peripheral

Question 53

What are the typical examiantion findings for glaucoma!

Answer 53

Mid dilated pupil Dull cornea from corneal clouding due to increased intraocular pressure obstructing aqueous outflow

Question 54

What are key glaucoma risk factors?

Answer 54

female, Asian and the use of certain medications including those with antimuscarinic properties, such as amitriptyline

Question 55

How to differentiate presentation of open and closed angle glaucoma.

Answer 55

POAG presents more insidiously with painless peripheral vision loss, often described as 'tunnel vision Acute angle closure glaucoma: ocular pain, decreased visual acuity, worse with mydriasis, haloes around lights

Question 56

Which visual field defect occurs in glaucoma.

Answer 56

Arcuate visual field defects causing vision loss in a curved 'arcuate fashion'

Question 57

What visual field defect is present in glaucoma?

Answer 57

Arcuate visual field defect in in a curved 'arcuate fashion

Question 58

What vision defect occurs early in glaucoma?

Answer 58

Peripheral visual field loss