BLUNT TRAUMA TO THE EYE

Uma VijayaraghavanRoll number: 159

INTRODUCTION

Injuries occuring during blunt trauma: Coup or direct eg: corneal abrasions

Countercoup due to transmitted pressure waves

MODES OF INJURY Blunt trauma may occur following: DIRECT BLOW to the eyeball by fist, ball

or blunt instruments like sticks or big stones.

ACCIDENTAL BLUNT TRAUMA to eyeball which occurs in roadside accidents,injuries by agricultural and industrial machines,fall upon a projecting object.

MECHANICS OF BLUNT TRAUMA

Blunt trauma can produce damage by diff forces:DIRECT IMPACT on globe: maximum damage at

the point where blow is received.

COMPRESSION WAVE FORCE: It is transmitted through fluid contents in all directions and strikes angle of anterior chamber, pushes iris diaphragm posteriorly and also strikes the retina and choroid and injury may sometimes be countercoup in nature.

REFLECTED COMPRESSION WAVE FORCE:after striking the outer coats the compression waves are reflected towards the posterior pole and may cause FOVEAL damage.

….CONTD

REBOUND COMPRESSION WAVE FORCE:After striking the posterior wall of the globe,the compression waves rebound back anteriorly.This force damages the retina,choroid by forward pull and lens-iris diaphragm by forward thrust from back. INDIRECT FORCE: ocular damage is caused

by forces from the bony walls and elastic contents of the orbit,when globe suddenly strikes these structures.

MODES OF DAMAGE1. Mechanical tearing of tissues of eyeball

2. Damage to the tissue cells causing damage to physiological activity

3. Vascular damage leading to ischaemia,oedema and haemorrhages.

4. Trophic changes due to disturbances of nerve supply.

5. Delayed complications of blunt trauma such as secondary glaucoma,retinal detachment etc.

TRAUMATIC LESIONS OF BLUNT TRAUMA

CLOSED GLOBE INJURY

GLOBE RUPTURE

EXTRAOCULAR LESIONS

CLOSED GLOBE INJURY Contusional injuries may vary from a simple corneal abrasion to an extensive intraocular damage.CORNEAo Simple abrasions:These are very painful and

diagnosed by fluorescein staining.These heal within 24hrs with pad and bandage applied after instilling antibiotic ointment.

o Recurrent corneal erosions(recurrent keractalgia) Caused by fingernail trauma. Patient presents with recurrent attacks of acute pain and lacrimation on opening eye in the morning and is due to abnormally loose attachment of epithelium to bowmans membrane.

PARTIAL CORNEAL TEARS

BLOOD STAINING OF CORNEA:from associated hyphaema and raised iop.Cornea is reddish brown or greenish in color and in later stages lead to dislocation of lens into anterior chamber.It clears very slowly from periphery towards the centre and may take upto 2 yrs.

DEEP CORNEAL OPACITY:It results from oedema of corneal stroma or occasionally from folds in the descemets membrane.

SCLERA Partial thickness scleral wounds occur

alone or with other lesions of closed globe type.

ANTERIOR CHAMBER TRAUMATIC HYPHAEMA or blood in

anterior chamber which occurs due to injury to iris or anterior ciliary vessels.

EXUDATES:these collect here following traumatic uveitis

IRIS,PUPIL AND CILIARY BODY

TRAUMATIC MIOSIS:occurs initially due to spasm of ciliary nerves or with spasm of accomodation.

TRAUMATIC MYDRIASIS(iridoplegia):It is permanent and is associated with traumatic cycloplegia.

RUPTURE OF PUPILARY MARGIN RADIATING TEARS IN THE IRIS STROMA IRIDODIALYSIS: detachment of iris from its root

at ciliary body which results in ‘D’ shaped pupil and a black biconvex area seen at the periphery.

ANTIFLEXION OF IRIS: refers to rotation of detached portion of iris in which its posterior portion faces anteriorly.It occurs following extensive iridodialysis.

RETROFLEXION OF IRIS:occurs when whole of iris is doubled back into ciliary region and becomes invisible.

TRAUMATIC ANIRIDIA:the completely torn iris sinks to the bottom of anterior chamber in the form of a small ball.

ANGLE RECESSION:refers to tear between the longitudinal and circular muscle fibres of ciliary body,characterised by deepening of ant chamber and widening of ciliary body on gonioscopy and leads to glaucoma.

INFLAMMATORY CHANGES:these include traumatic iridocyclitis, post traumatic iris atrophy etc.

TREATMENT-consist of atropine,antibiotics and steroids.

iridodialysis:

Traumatic aniridia:

LENS VOSSIUS RING:It is a circular ring of brown

pigment seen on the anterior capsule.It occurs due to striking of contracted pupillary margin against the lens.

CONCUSSION CATARACT:due to imbibition of aqueous and due to direct mechanical effects of the injury on lens fibres and may take any of the following shapes-

1. Discrete subepithelial opacities2. Early rosette cataract3. Late rosette cataract4. Traumatic zonular cataract5. Diffuse concussion cataract6. Early maturation of senile cataract

CONTD.. Traumatic absorption of the lens:it can occur

in children leading to aphakia. Subluxation of lens:due to partial tear of

zonules and there is displacement of lens but is present in the pupillary area-it can be lateral or vertical.

Dislocation of lens:when rupture of zonules is complete and can be intraocular or extraocular.

INTRAOCULARinto anterior chamber or posterior vitreousEXTRAOCULARsubconjunctival space or may fall outside the eye

Vossius ring

Rosette cataract

Subluxation of lens

VITREOUS Liquefaction and appearance of clouds of

fine pigmentary opacities.

Detachment of the vitreous either anterior or posterior.

Vitreous haemorrhage.

Vitreous herniation in anterior chamber may occur with subluxation or dislocation of lens.

CHOROID Rupture of choroid: is concentric to optic disc

and situated temporal to it and can be single or multiple.On fundus examination it looks like whitish crescent with fine pigmentation at its margins.Retinal vessels pass over it.

Choroidal haemorrhage may occur under retina or may even enter the vitreous if retina is torn.

Choroidal detachment

Traumatic choroiditis:seen on fundus examination as patches of pigmentation and discoloration after eye becomes silent.

Rupture of choroid

RETINA COMMOTIO RETINAE(Berlin’s

oedema):common occurences following a blow on the eye.It manifests as milky white cloudiness involving a considerable area of posterior pole with a cherry- red spot in the foveal region.It may disappear after some days or may be followed by pigmentary changes.

RETINAL HAEMORRHAGES:eg:flame shaped and preretinal D shaped haemorrhage may be associated with traumatic retinopathy.

RETINAL TEARS:these follow a contusion in eyes suffering from myopia or senile degenerations.

TRAUMATIC PROLIFERATIVE RETINOPATHY:occur secondary to vitreous haemorrhage.

RETINAL DETACHMENT: follows retinal tears or vitreo-retinal tractional bands.

CONCUSSION CHANGES AT MACULA: traumatic macular oedema followed by pigmentary degeneration.

Sometimes, a macular cyst is formed,which on rupture is converted to a lamellar or full thickness macular hole.

Commotio retinae-milkiness of posterior pole

Retinal haemorrhage

Macular hole

IOP CHANGES IN CLOSED GLOBE INJURY

TRAUMATIC GLAUCOMA

TRAUMATIC HYPOTONY: it may follow damage to the ciliary body and may result in phthisis bulbi.

TRAUMATIC CHANGES IN REFRACTION

Myopia may follow ciliary spasm or rupture of zonules or anterior shift of lens

Hypermetropia and loss of accomodation may result from damage to the ciliary body.

GLOBE RUPTURE It is a full-thicknesswound of eye-wall caused

by blunt object and can occur in 2 ways:

DIRECT RUPTURE: at the site of injury.

INDIRECT RUPTURE:occurs because of compression force.The impact results in momentary increase in IOP and inside out injury at the weakest part of the eyewall,i.e in the vicinity of canal of schlemm concentric to the limbus.The superonasal limbus is the most common site.

TREATMENT:A badly damaged globe should be enucleated.In less severe cases it can be repaired under general anaesthesia.

EXTRAOCULAR LESIONS

CONJUNCTIVAL LESIONS: subconjunctival haemorrhages are seen as bright red spot.

EYELID LESION: Ecchymosis of eyelids.Because of loose subcutaneous tissue,blood collects easily into the lids and produces BLACK-EYE.Traumatic ptosis may follow damage to leavtor muscle. Laceration and avulsion of lids can occur.

OPTIC NERVE INJURIES: associated with fracture of base of skull.

ORBITAL INJURY:there may occur fracture of orbital walls. Orbital haemorrhage may produce sudden proptosis. Orbital emphysema may occur following ethmoidal sinus rupture.