BLUNT OCULAR TRAUMA

The most common causes of blunt trauma are:•Sports related injuries such as cricket,•basketball, water sports and racquet sports.•Elastic luggage straps.•Aggression.•Automobile accidents

Mechanism of Injury•The eye is a relatively incompressible fluid-filled globe.•kinetic energy transfer from the moving object to the globe.•The energy alters the shape of the globe

This alteration in shape has four components:•compression,•decompression,•overshoot,•and oscillations

•With each oscillation more and more energy is lost•There is progressive reduction in oscillatory extent and eventual termination.

• As the eye oscillates, each ocular layer moves at a different rate due to different elasticity .

• This results in generation of shear forces at the interfaces of tissues with different elasticities.

• These shear forces causes tissue damage.

The extent of ocular damage depends on:

size of the blunt object

hardness of the blunt object

velocity of the blunt object

force imparted directly to the eye

Direct blow to the globe from a blunt object “larger than the orbital opening”

Energy absorbed by all of the orbital contents leading to rise of intra-orbital pressure

Fractures of the thin bones of orbit

This "pressure-release valve" may prevent serious ocular injury

Direct blow to the globe from a blunt object “smaller than

orbital opening”

Energy directly absorbed by the eye ball

Severe increase in IOP and consequently greater ocular

damage

Effects of blunt ocular trauma

•Although the impact of a blunt trauma is primarily absorbed by lens-iris diaphragm & vitreous base, damage can also occur at a distant sites such as the posterior pole.

Ocular manifestation:•Hyphema (73 %),•Angle recession (71 %),•Iris sphincter tears (20 %),•Iridodialysis (10 %),•Cyclodialysis (3.4 %),•Lens dislocation (15 %),•Traumatic cataract (10 %),•Choroidal rupture (7 %),•Retinal tear or detachment (7 %),•Berlin's edema (35.5 %),•Globe rupture (4.6 %),•Blow-out-fracture (8.3 %).

Ocular manifestation of blunt trauma

subconjunctival hemorrhage

Corneal abrasion

Corneal edema

Iris and Ciliary body

• Traumatic iridocyclitis • Traumatic miosis• Traumatic mydriasis• Sphincter tear• Iridodialysis

• D shaped pupil• Uniocular diplopia

• Traumatic aniridia or irideremia

Iris and ciliary body

• Angle recession • Rupture of anterior part of ciliary body• Tear between circular and longitudinal fibres• Hyphaema • Late onset glaucoma

• Traumatic hyphaema• Asso with angle recession/iridodialysis/cyclodialysis• IOP assesment• Re-bleeding• Level of hyphaema

Lens

• Vossius ring – iris imprint on anterior lens capsule• Concussion injury

• Mechanical damage to lens fibres• Capsular tear

• Peripheral / Thinnest portion• Rosette shaped cataract

• Star shaped cortical sutures are delineated• Feathery lines of opacities radiate from them

• Rapid intumescence of lens with secondary glaucoma• Dislocation • Subluxation

Vitreous

• Detachment • Hemorrhage• Liquefaction of vitreous

Choroid

• Rupture – concentric to disc usually temporal to it• Whitish crescent with fine pigmentation at its

margin• Choroidal hemorrhage• Choroidal detachment

Retina

• Commotio retinae (Berlin’s edema)• Milky white cloudiness of posterior pole • Cherry red spot at fovea

• Retinal hemorrhages• Retinal tears• Retinal detachment• Traumatic retinitis proliferans• Traumatic macular degeneration• Macular hole

Globe rupture

summary