Visual lossBy:Fahimah

Faculty of Medicine,

UiTM, Malaysia

DefinitionGoodLowblind

6/6 – 6/126/18 –

6/60< 3/60

• ACUTE– Acute glaucoma– Central retinal artery

occlusion– Optic neuritis– Retinal detachment

• CHRONIC– Glaucoma– Cataract – Diabetic retinopathy– Central retinal vein

occlusion– Age-related macular

degeneration

GLAUCOMAA progressive optic neuropathy Changes of optic disc appearanceIrreversible visual field defects frequently with raised IOP.

Raised intraocular pressure is a significant risk factorNormal IOP: 12-21mmHg

Worldwide- second leading cause of blindness

High IOP but normal optic discs – Ocular hypertension

Normal IOP but glaucomatous optic disc damage-Normal tension glaucoma

Mechanism of visual loss in glaucoma

Retinal ganglion cell atrophy

Thinning of the inner nuclear and nerve fiber layers of retina

Axonal loss in the optic nerve

Optic disk becomes atrophic

Enlargement of the optic cup

Classification Primary Adult Glaucoma

Open Angle Glaucoma -chronicAngle Closure Glaucoma - acute

Secondary GlaucomaCongenital and Developmental Glaucoma

Acute Primary Angle Closure Glaucoma

Occur due to a sudden total angle closure leading to severe rise in IOP

Does not terminates on its ownThus, if not treated, lasts for many days

GROUPS AT RISK

• HYPERMETROPES – have shallow ant chamber and shorter axial

length eye

• AGE – with increasing age, lens tend to increase in size

• WOMEN – hv shallower ant chamber

• RACE – Asian groups, due to their shallower anterior

chamber depth

SYMPTOMSThe eye becomes red and painfulRapidly progressive impairment of visionPhotophobicSystemically unwell with nausea and abd painColoured haloes

SIGNS of ACUTE ANGLE-CLOSURE GLAUCOMACicumcorneal injectionHazy corneaShallow Anterior ChamberAnterior Chamber inflammationFixed, mid-dilated, oval pupilMarkedly increased IOPCorneal oedemaClosed angle on gonioscopy

MECHANISMApposition of the lens to the back

of iris

prevent the flow of aqueous

Aqueous then collects behind the iris and pushes it on to the

trabecular meshwork

preventing the drainage of aqueous

IOP rises rapidly

Precipitating factors for Angle Closure

MydriasisEmotional upsetDim illuminationMedications

anticholinergic or sympathomimetic activity eg. Atropine, antidepressant, nebulized bronchodilator, or nasal decongestant

Evening hoursExtreme miosisProne Position

TREATMENTMedicalLaserSurgery

MEDICALAcetazolamide – to reduce IOP by reducing

the secretion of aqueousGiven 500mg IM or IVPilocarpine 4% drops – to contract the pupil.SURGICAL Laser peripheral iridotomySurgical peripheral iridectomy

CENTRAL RETINAL ARTERY OCCLUSION

SYMPTOMSPainless visual loss ( occur within seconds)Previous history of transient visual loss

SIGNSVisual acuity ranges between counting fingers

and light perceptionOphthalmoscopically, the superficial retina

becomes opacified except in the foveola (cherry red spot)

Central retinal artery occlusion

Treatment Retinal damage become irreversible after

about 90 minutes.Decreased IOP: anterior chamber

paracentesis, I/V acetozolamideInhaled oxygen-carbon dioxide mixture-induce

retinal vasodilationDirect infusion of a thrombolytic agent into

opthalmic artery (within 8 hours after onset).

referenceKanski , ophthalmology textbook, 5th edition.