0.1% of over 40s

1.5% of Chinese population over 50

## Risk factors
- Demographic
    - Age >40
    - Female
    - Ethnicity: chinese, south east asian

- Anatomical
    - Narrow angle/shallow AC
        - Anterior iris-lens diaphragm
        - Large lens/cataract
        - Small corneal diameter
        - Short axial length (hypermetropic)
        - Lens thickness-to-axial length ratio

<HotTopic>**Anterior lens vault** on anterior segment OCT, the distance between anterior lens and a horizontal line joining the scleral spurs. In PAC, the lens vault is relatively increased.</HotTopic>

- Nanophthalmos: **bilateral** short globes (&lt;20mm) with hyperopia, reduced corneal diameter &lt;12mm and thick sclera (impedes uveoscleral outflow).The eye is uniformly reduced in size but the lens is normal or enlarged and the sclera is abnormally thick

- Pupillary block: most common mechanism
    - Increased risk in microspherophakia (found in Weill-Marchesani syndrome)

- Plateau iris
    - Anteriorly placed ciliary body that apposes the peripheral iris
    - AC depth is normal centrally but shallow peripherally
    - Double-hump sign on gonioscopy
    - Plateau-iris syndrome: iris bunches up peripherally and blocks trabeculum (may cause angle closure **despite patent PI**) see below section

## Classification
- Narrow angle: after dark-room gonioscopy in primary position
- Iridotrabecular contact (ITC): on gonioscopy
- Primary angle closure (PAC): ITC **plus** raised IOP or peripheral anterior synechiae or symptoms
    - Primary angle closure suspect (PACS): >2 quadrants (180 degrees) of ITC but normal IOP, no PAS, normal optic nerve
    - Zhongshan Angle Closure Prevention Study (**ZAP**): found limited benefit of prophylactic PI for PAC suspects, therefore widespread PI for PACS was not recommended
    - Consider cataract surgery if IOP >30 (or PACG) with visually significant lens opacity (**EAGLE** RCT showed clear-lens extraction was as effective but with better IOP control and better QoL compared to standard care with PI and topical medications)

- Acute primary angle closure: ITC with symptomatic raised IOP
- Primary angle closure glaucoma: PAC with disc and/or VF changes
    - YAG PI is important but beware of IOP spikes if significant peripheral anterior synechiae
    - Medical and surgical treatment as for POAG
    - Beware of increased risk of aqueous misdirection syndrome

## Clinical features
- Pain
- Blurred vision
- Haloes
- nausea/vomiting
- Red eye
- Raised IOP
- Corneal oedema
- Closed angle
- Fixed semi-dilated pupil
- Iris atrophy/transillumination defects
- Glaucomflecken: white flecks representing degenerated lens epithelium due to severe raised IOP, seen just beneath the anterior capsule
- Contralateral narrow angle
- Shallow AC

<HotTopic>Distinguishing phacomorphic from primary angle closure. Can be tricky but best done by examining the fellow eye: shallow AC in PACG compared to normal depth in phacomorphic glaucoma.</HotTopic>

## Management of acute primary angle closure

1. Systemic acetazolamide: 500mg IV stat then 250mg oral QDS
2. Topical: beta-blocker (timolol), sympathomimetic (apraclonidine), steroid (maxidex), pilocarpine 2% (twice in first hour then QDS)
3. Admission
4. Corneal indentation with 4-mirror goniolens may help relieve pupil block
5. Lying patient supine may help lens to fall away from iris
6. Pilocarpine 1% to contralateral eye while awaiting YAG PI
7. Hourly IOP check
8. Systemic hyperosmotic if IOP not improving: mannitol 20% solution 1-1.5g/kg IV
9. Acute YAG PI if IOP still not improving (topical glycerin can temporarily reduce corneal oedema)
10. IOP still high: review diagnosis ?aqueous misdirection; consider repeating or surgical PI, argon iridoplasty, paracentesis, cyclodiode, emergency cataract extraction
11. Bilateral laser or surgical PI is definitive
12. Long-term chronic IOP due to synechial closure may require topical/surgical treatment

<HotTopic>Fellow eye PI after attack of PACG: 50-75% of patients develop fellow eye attack within 5-10 years.</HotTopic>

### Mannitol

- Hyperosmotic: increases blood osmolality to draw water out of the vitreous
- Faster administration and large dose will increase the gradient and thus give a more potent effect
- Less effect when the blood-aqueous barrier is disrupted (eg. uveitis)
- Increase cardiac preload: avoid use in congestive heart failure, renal failure/dialysis patients, also risk of cerebral complications


Glaucoma

Primary Angle Closure

Intro

FRCOphth Part 2 Study Notes

Tumours, masses and neoplasia

Tumours overview

Uveitis

Uveitis background

Anterior uveitis

Intermediate uveitis

Uveitis in JIA

Uveitis with JIA

Retinal vasculitis

Sarcoidosis

Behcet's disease

Toxoplasmosis

Strabismus

Overview

Viral uveitis

Esotropia

Fungal uveitis

Mycobacterial uveitis

Adnexal masses

Exotropia

Spirochaetal uveitis (including Syphilis)

Melanoma

Nematode uveitis

Retinoblastoma

Retinoblastoma (for Part 2)

Incomitent

Voyt-Koyanagi-Harada syndrome

Conjunctival intraepithelial neoplasia

Vertical deviations

Orbit and ocular adnexae

Orbit

Sympathetic ophthalmia

AV Malformations and hamartomas

Arteriovenous malformations and hamartomas

Restriction syndromes

Paediatrics

Leucocoria

Congenital Cataract

Paediatric Glaucoma

Retinopathy of prematurity

Retinopathy of Prematurity

ROP-like disorders

Congenital nasolacrimal duct obstruction

White dot syndromes

Aniridia: Short Arm 11 Deletion (11p13)

Choristomas

Management Of Amblyopia

Alphabet patterns

Iris Nodules

Scleritis

Meningioma

Strabismus surgery

Optic nerve glioma

Lymphoma

Extraocular Muscles

Rhabdomyosarcoma

Idiopathic orbital inflammation

Orbital neuroblastoma

Anterior Persistent Foetal Vasculature

Lacrimal system

Metastatic lesions

Surgical Retina

Retinal Detachment

Vitreoretinal Interface And Macular Hole

Epiretinal Membrane

Medical Retina

Diabetic Eye Disease

Orbital Blood Vessels

Retinal Vascular Disease

Macular Degeneration

Central Serous Chorioretinopathy (CSCR)

Sickle Cell Retinopathy

Retinitis Pigmentosa

Albinism

Retinal Telangiectasias

Miscellaneous Retinopathies

Atropine And Myopia Progression

Pharmacology

Side Effects Of Systemic Drugs

Foetal Alcohol Syndrome

Neuro-ophthalmology

Optic Neuropathy

Papilloedema

Idiopathic Intracranial Hypertension

Chiasmal Disorders

Retrochiasmal Disorders

Migraine

Paranasal Sinuses

Supranuclear Motility Disorders

Third Nerve Palsies

Fourth Nerve Palsies

Sixth Nerve Palsies

Seventh Nerve Palsies

Anisocoria

Myasthenia Gravis

Myopathies

Blepharospasm

Functional Visual Loss

Lacrimal Glands

Phakomatoses

Developmental diseases

Tear Film

Eyelids

Blinking

Lid Malpositions

Anterior segment - ocular surface

Conjunctiva

Conjunctivitis

Sclera

Pigmented Conjunctival Lesions

Squamous Cell Carcinoma Of The Conjunctiva

Ocular Cicatricial Pemphigoid

Cornea

Corneal Structure And Development