Katarzyna Pikulska
Medical University of Warsaw
Blunt trauma and penetrating trauma of the eye
Blunt trauma
Etiology
Blunt trauma may occur following:
- direct blow to the eye ball by fist, ball or blunt instruments like sticks, and big stones.
- accidental blunt trauma to eyeball may also occur in roadside accidents, automobile accidents, injuries by agricultural and industrial instruments/ machines and fall upon the projecting blunt objects
Characteristical signs
Closed globe injury
Cornea
1. Simple abrasions. These are very painful and diagnosed by fluorescein staining. These usually heal up within 24 hours with `pad and bandage' applied after instilling antibiotic ointment.
2. Recurrent corneal erosions (recurrent keractalgia). These may sometimes follow simple abrasions, especially those caused by fingernail trauma. Patient usually gets recurrent attacks of acute pain and lacrimation on opening the eye in the morning. This occurs due to abnormally loose attachment of epithelium to the underlying Bowman's membrane.
3. Partial corneal tears (lamellar corneal laceration). These may also follow a blunt trauma.
4. Blood staining of cornea. It may occur occasionally from the associated hyphaema and raised intraocular pressure. Cornea becomes reddish brown or greenish in colour and in later stages simulates dislocation of the clear lens into the anterior chamber. It clears very slowly from the periphery towards the centre, the whole process may take even more than two years.
Sclera
Partial thickness scleral wounds (lamellar scleral lacerations) may occur alone or in association with other lesions of closed-globe injury.
Anterior chamber
1. Traumatic hyphaema (blood in the anterior chamber). It occurs due to injury to the iris or ciliary body vessels.
2. Exudates. These may collect in the anterior chamber following traumatic uveitis.
Iris, pupil and ciliary body
1. Traumatic miosis. It occurs initially due to irritation of ciliary nerves. It may be associated with spasm of accommodation.
2. Traumatic mydriasis (Iridoplegia). It is usually permanent and may be associated with traumatic cycloplegia.
3. Rupture of the pupillary margin is a common occurrence in closed-globe injury.
4. Radiating tears in the iris stroma, sometimes reaching up to ciliary body, may occur
occasionally.
5. Iridodialysis i.e., detachment of iris from its root at the ciliary body occurs frequently. It results in a D-shaped pupil and a black biconvex area seen at the periphery.
6. Antiflexion of the iris. It refers to rotation of the detached portion of iris, in which its posterior surface faces anteriorly.
7. Retroflexion of the iris. This term is used when whole of the iris is doubled back into the ciliary region and becomes invisible.
8. Traumatic aniridia or iridremia. In this condition, the completely torn iris (from ciliary body) sinks to the bottom of anterior chamber in the form of a minute ball.
9. Angle recession refers to the tear between longitudinal and circular muscle fibres of the ciliary body. It is characterized by deepening of the anterior chamber and widening of the ciliary body band on gonioscopy. Later on it is complicated by glaucoma.
10. Inflammatory changes. These include traumatic iridocyclitis, haemophthalmitis, post-traumatic iris atrophy and pigmentary changes.
Lens
It may show following changes:
1. Vossius ring. It is a circular ring of brown pigment seen on the anterior capsule. It occurs due to striking of the contracted pupillary margin against the crystalline lens. It is always smaller than the size of the pupil.
2. Concussion cataract. It occurs mainly due to imbibition of aqueous and partly due to direct mechanical effects of the injury on lens fibres. It may assume any of the following shapes:
- discrete subepithelial opacities are of most common occurrence.
- early rosette cataract (punctate
- traumatic zonular cataract. It may also occur in some cases, though rarely.
- diffuse (total) concussion cataract. It is of frequent occurrence.
- early maturation of senile cataract may follow blunt truma.
Globe rupture
Globe rupture is a full-thickness wound of the eyewall caused by a blunt object. Globe rupture may occur in two ways:
Direct rupture may occur, though rarely, at the site of injury.
Indirect rupture is more common and occurs because of the compression force. The impact results in momentary increase in the intraocular pressure and an inside-out injury at the weakest part of eyewall, i.e., in the vicinity of canal of Schlemm concentric to the limbus. The superonasal limbus is the most common site of globe rupture (contrecoup effect— the lower temporal quadrant being most exposed to trauma).
Extraocular lesions
Extraocular lesions caused by blunt trauma are as follows:
1. Conjunctival lesions. Subconjunctival haemorrhage occurs very commonly. It appears as a bright red spot. Chemosis and lacerating wounds of conjunctiva (tears) are also not uncommon.
2. Eyelid lesion. Ecchymosis of eyelids is of frequent occurrence. Because of loose subcutaneous tissue, blood collects easily into the lids and produces `blackeye'. There may occur laceration and avulsion of the lids. Traumatic ptosis may follow damage to the levator muscle.
3. Lacrimal apparatus lesions. These include dislocation of lacrimal gland and lacerations of lacrimal passages especially the canaliculi.
4. Optic nerve injuries. These are commonly associated with fractures of the base of skull. These may be in the form of traumatic papillitis, lacerations of optic nerve, optic nerve sheath haemorrhage and avulsion of the optic nerve from back of the eye.
5. Orbital injury. There may occur fractures of the orbital walls; commonest being the `blow-out fracture' of the orbital floor. Orbital haemorrhage may produce sudden proptosis. Orbital emphysema may occur following ethmoidal sinus rupture.
Work-up
Imaging Studies Because choroidal ruptures occur as a consequence of blunt ocular trauma, the ocular examination must be thorough to rule out orbital fractures or globe ruptures. Consider CT scanning and MRI of the eye and orbit under appropriate circumstances.Fluorescein angiography may be a useful adjunct to detect CNV. If CNV is absent, hypofluorescence occurs during the early phase of the angiogram due to disruption of the choriocapillaris. During later stages, hyperfluorescence occurs from the adjacent healthy choriocapillaris. If CNV is present, early hyperfluorescence followed by late leakage is present on the angiogram. Indocyanine green (ICG) angiography may be useful if subretinal blood blocks or hides CNV detection on a fluorescein angiogram. Histologic Findings Direct choroidal ruptures are characterized by a complete absence of choroid and RPE. The overlying retina is intact but atrophic.
In indirect choroidal ruptures, CNV is a common finding during the early healing phases. Most CNV is in the subretinal space (Gass type 2). With time, most CNV involutes spontaneously. In a small number of cases, a disciform scar or fibrous tissue may grow into the retina and vitreous cavity.
Differential diagnose
Angioid streaks, ARMDE, subretinal neovascular membranes, lchoroidal neovascularization, presumed ocular histoplasmosis syndrome, pseudoxanthoma elasticum
Treatment
Loosely attached epithelium should be removed by debridement and `pad and bandage' applied for 48 hours, so that firm healing is established.
It consists of atropine, antibiotics and steroids. In the presence of ruptures of pupillary margins and subluxation of lens, atropine is contraindicated.
. A badly damaged globe should be enucleated. In less severe cases, repair should be done under general anaesthesia. Postoperatively atropine, antibiotics and steroids should be used.
Follow up
Late rosette cataract. It develops in the posterior cortex 1 to 2 years after the injury. Its sutural extensions are shorter and more compact than the early rosette cataract.
Rupture of the globe may be associated with prolapse of uveal tissue, vitreous loss, intraocular haemorrhage and dislocation of the lens.
Penetrating trauma of the eye
Etiology
As mentioned earlier, penetrating injury is defined as a single full-thickness wound of the eyewall caused by a sharp object. While perforating injury refers to two full-thickness wounds (one entry and one exit) of the eyewall caused by a sharp object or missile. These can cause severe damage to the eye and so should be treated as serious emergencies.
Modes of injury
1. Trauma by sharp and pointed instruments like needles, knives, nails, arrows, screw-drivers, pens, pencils, compasses, glass pieces and so on.
2. Trauma by foreign bodies travelling at very high speed such as bullet injuries and iron foreign bodies in lathe workers
Characteristical signs
1. Mechanical effects of the trauma or physical changes. These are discussed later in detail.
2. Introduction of infection. Sometimes, pyogenic organisms enter the eye during perforating injuries, multiply there and can cause varying degree of infection depending upon the virulence and host defence mechanism. These include: ring abscess of the cornea, sloughing of the cornea, purulent iridocyclitis, endophthalmitis or panophthalmitis . Rarely tetanus and infection by gas-forming organisms (Clostridium welchii) may also occur.
3. Post-traumatic iridocyclitis. It is of frequent occurrence and if not treated properly can cause devastating damage.
4. Sympathetic ophthalmitis. It is a rare but most dangerous complication of a perforating injury. It is described separately.
Mechanical effects
Mechanical effects of penetrating/perforating trauma on the different ocular structures with their management are enumerated here briefly.
1. Wounds of the conjunctiva. These are common and usually associated with subconjunctival haemorrhage. A wound of more than 3 mm should be sutured.
2. Wounds of the cornea. These can be divided into uncomplicated and complicated wounds.
- uncomplicated corneal wounds. These are not associated with prolapse of intraocular contents. Margins of such wounds swell up and lead to automatic sealing and restoration of the anterior chamber.
- complicated corneal wounds. These are associated with prolapse of iris.
sometimes lens matter and even vitreous.
5. A badly (severely) wounded eye. It refers to extensive corneo-scleral tears associated with prolapse of the uveal tissue, lens rupture, vitreous loss and injury to the retina and choroid. Usually there seems to be no chance of getting useful vision in such cases. So, preferably such eyes should be excised.
INTRAOCULAR FOREIGN BODIES
Penetrating injuries with foreign bodies are not infrequent. Seriousness of such injuries is compounded by the retention of intraocular foreign bodies (IOFB). Common foreign bodies responsible for such injuries include: chips of iron and steel (90%) particles of glass, stone, lead pellets, copper percussion caps, aluminium, plastic and wood.
Modes of damage
A penetrating/perforating injury with retained foreign body may damage the ocular structures by the following modes:
- mechanical effects.
- introduction of infection.
- reaction of foreign bodies.
- post-traumatic iridocyclitis.
- sympathetic ophthalmitis
Mechanical effects
Mechanical effects depend upon the size, velocity and type of the foreign body. Foreign bodies greater than 2 mm in size cause extensive damage. The lesions caused also depend upon the route of entry and the site up to which a foreign body has travelled. In general these include:
- corneal or/and scleral perforation, hyphaema, iris hole;
- rupture of the lens and traumatic cataract;
- vitreous haemorrhage and/or degeneration;
- choroidal perforation, haemorrhage and inflammation;
- retinal hole, haemorrhages, oedema and detachment.
Locations of IOFB. Having entered the eye through the cornea or sclera a foreign body may be retained at any of the following sites:
1. Anterior chamber. In the anterior chamber, the IOFB usually sinks at the bottom. A tiny foreign body may be concealed in the angle of anterior chamber, and visualised only on gonioscopy.
2. Iris. Here the foreign body is usually entangled in the stroma.
3. Posterior chamber. Rarely a foreign body may sink behind the iris after entering through pupil or after making a hole in the iris.
4. Lens. Foreign body may be present on the anterior surface or inside the lens. Either an opaque track may be seen in the lens or the lens may become completely cataractous.
5. Vitreous cavity. A foreign body may reach here through various routes, which are depicted below
6. Retina, choroid and sclera. A foreign body may obtain access to these structures through corneal route or directly from scleral perforation.
7. Orbital cavity. A foreign body piercing the eyeball may occasionally cause double perforation and come to rest in the orbital tissues.
Work-up
It is a matter of extreme importance particularly as the patient is often unaware that a particle has entered the eye. To come to a correct diagnosis following steps should be taken:
1. History. A careful history about the mode of injury may give a clue about the type of IOFB.
2. Ocular examination. A thorough ocular examination with slit-lamp including gonioscopy should be carried out. The signs which may give some indication about IOFB are: subconjunctival haemorrhage, corneal scar, holes in the iris, and opaque track through the lens. With clear media, sometimes IOFB may be seen on ophthalmoscopy in the vitreous or on the retina. IOFB lodged in the angle of anterior chamber may be visualised by gonioscopy.
3. Plain X-rays orbit. Antero-posterior and lateral views are indispensable for the location of IOFB, as most foreign bodies are radio opaque.
4. Localization of IOFB. Once IOFB is suspected clinically and later confirmed, on fundus examination and/or X-rays, its exact localization is mandatory to plan the proper removal. Following techniques may be used:
- radiographic iocialization. Before the advent of ultrasonography and CT scan, different specialized radiographic techniques were used to localize IOFBs; which are now obsolete. However, a simple limbal ring method which is still used is described below:
Limbal ring method. It is the most simple but now-a-days, sparingly employed technique. A metallic ring of the corneal diameter is stitched at the limbus and X-rays are taken. One exposure is taken in the anteroposterior view. In the lateral view three exposures are made one each while the patient is looking straight, upwards and downwards, respectively. The position of the foreign body is estimated from its relationship with the metallic ring in different positions
- ultrasonographic localization. It is being used increasingly these days. It can tell the position ofeven non-radioopaque foreign bodies.
- CT scan. With axial and coronal cuts, CT scan is resently the best method of IOFB localization. It rovides cross-sectional images with a sensitivity nd specificity that are superior to plain adiography and ultrasonography.
Differential diagnose
Non-penetrating blunt trauma, chemical trauma.
Treatment
IOFB should always be removed, except when it is nert and probably sterile or when little damage has een done to the vision and the process of removal ay be risky and destroy sight (e.g., minute FB in the etina).
Removal of magnetic IOFB is easier than the removal of non-magnetic FB. Usually a hand-held electromagnet is used for the removal of magnetic foreign body. Method of removal depends upon the site (location) of the IOFB as follows:
1. Foreign body in the anterior chamber. It is removed through a corresponding corneal incision directed straight towards the foreign body. It should be 3 mm internal to the limbus and in the quadrant of the cornea lying over the foreign body
- magnetic foreign body is removed with a handheld magnet. It may come out with a gush of aqueous.
- non-magnetic foreign body is picked up with toothless forceps.
2. Foreign body entangled in the iris tissue
(magnetic as well as non-magnetic) is removed by performing sector iridectomy of the part containing foreign body.
Corneal wounds with iris prolapse should be sutured meticulously after abscising the iris. The prolapsed iris should never be reposited; since it may cause infection. When associated with lens injury and vitreous loss, lensectomy and anterior vitrectomy may be performed along with repair of the corneal wound.
A small central wound does not need stitching. The only treatment required is pad and bandage with atropine and antibiotic ointments. A large corneal wound (more than 2 mm) should always be sutured.
Follow up
Intraocular infection is the real danger to the eyeball. Fortunately, small flying metallic foreign bodies are usually sterile due to the heat generated on their commission. However, pieces of the wood and stones carry a great chance of infection. Unfortunately, once intraocular infection is established it usually ends in endophthalmitis or even panophthalmitis
1