We have already discussed about Blunt Mechanical Injuries in Part I (BHJ 2005; 47 (1) : 44). In this we will be discussing about Penetrating Injuries.
Aetiology of Penetrating Injuries:
- Domestic – e.g. due to knife, scissors, or needle
- Sports and outdoor games: e.g. Injuries with spear bow and arrow.
- Industrial hazards: e.g injuries sustained while working on a machine due to flying particles.
- Vehicular accidents – while travelling by scooter, bus, train, plane etc.
- Agriculture: horn of animals like buffalo, Cow or bullock. Sudden movement of a tree twig with wind. Biting by Pet Animals like Dog or Cat. Pecking by a bird like Stork, Hen or Crow.
- Illegal Assault -e.g. knife, Axe, bullet, arrow, spear, Sword etc.
- War Injuries
Mainly depends on the nature and severity of the injury. It may present with:
Orbital fracture: The commonest injury leading to fracture is injury with a knife, scissors or bullet. The floor and medial wall of orbit have thinnest bone as their component and hence fracture of floor of orbit (Roof of maxillary sinus) is commonest. It can be detected clinically by hypophoria (depression of eyeball), and restriction of ocular movements if the muscles are entrapped in the fracture. In case the injury has involved intracranial cavity C.S.F. leakage and unconsciousness will be present. This will require immediate Neuro surgery management.
Lids: Tear, Coloboma and Avulsion of lids : Injury due to sharp object are more prone to get avulsion of lid. Tear and coloboma can occur due to vehicular accidents and agricultural injuries. Surgical resuturing of tissues is done in layers. If there is loss of tissue, plastic surgery may be needed.
Ptosis: Damage to nerve or muscle fibres can lead to ptosis, which can improve within 6 months after nerve fibres regenerate and muscle fibres heal. If there is no correction within 6 months surgery to correct ptosis can be attempted. Injection of B-complex having hydroxy-cobalamine preparation (like Tri-redisol H) 2 ml intramuscular on alternate days, 5 injections can be helpful.
Lacrimal Apparatus: Canalicular tears can occur in cases of lid tears and avulsion, especially when nasal (medial) part of lid is involved. If the lid tear is sutured without repairing canalicular tear, it can lead to severe watering because of blockage of lacrimal fluid drainage. Canalicular tear should be identified and repaired with help of a special pig tail probe.
Conjunctival tear: Can be sutured with 6 ‘0’black silk under local Anaesthesia.
Cornea: If wound is small the margins swell up soon and become cloudy due to accumulation of fluid. This facilitates closure of the wound and restoration of anterior chamber. They heal well unless secondary infection occurs. If the wound is large adhesion of the iris or prolapse occurs. In small recent injuries the prolapsed iris may be replaced by intraocular pilocarpine injection and constriction of pupil. If the iris is exposed for some time it must be abscised to avoid danger of infection and wound sutured with 8.0, 9.0 or 10.0 black silk. If the wound is irregular with loss of tissue, therapeutic keratoplasty may be needed because apposition of wound edges may not be possible and even if done it causes corneal opacity and irregular astigmatism requiring keratoplasty later.
Sclera: Wounds more than 3 to 4 mm may be associated with ciliary body choroidal vitreous or lens prolapse. The wound is thoroughly explored prolapse tissue excised and sutured. A girdle of cryoapplication is done around the wound to cause chorioretinal adhesion to prevent retinal detachment.
Anterior Chamber: If dirt, organism or vegetable matter is retained in anterior chamber pyogenic infection leads to purulent iridocyclitis with hypopyon. It needs thorough anterior chamber wash with antibiotic added to normal saline immediately, if not done it leads to endophthalmitis or panaophthalmitis.
Lens: If wound in capsule is small; aqueous enters through it and swelling of lens fibres causes sealing of wound with localized cataract. If wound is unsealed gradual seepage of aqueous leads to opacities along entire lens in form of feathery lines particularly in posterior cortex causing rosette cataract. It requires planned cataract surgery with intraocular lens implant.If the capsule tear remains open for long time flocculent cortical grey masses protrude through the opening in the capsule and float in the whole anterior chamber. It needs immediate surgery, aspiration of cortex to avoid phakotoxic uveitis and secondary glaucoma.
Vitreous: If vitreous is incarcerated in the wound vitrectomy is needed before suturing the corneal or scleral wound. If there is associated traumatic cataract or lens incarceration in the wound it should be extracted too and scleral fixated intraocular lens may be implanted.
Iris : with intra ocular foreign body a punctate hole is seen due to retraction of severed blood vessels; the small blood clot formed is rapidly absorbed. There is no sign of repair and hole permanently remains. If a larger area of iris is torn it leads to hyphaema. If there is infection or retained foreign body severe iritis, may result.
Ciliary body and choroid haemorrhage with leucocytic infiltration of the wound with formation of fibrovascular scar with pigmentation occurs. Ciliary body wound may cause irritative recurrent uveitis with shrinkage of globe due to scar tissue.
Retina: Immediately around wound nervous element of retina show degenerative changes within nerve fibre and ganglion cell layer. Secondary gliosi with reparative attempts from mesoblastic elements may spread widely over retina pulling it causing detachment.
Retained foreign body : 90% are iron or steel chips, remaining 10% are glass, lead pellets, copper percussion caps, wood stone, thorn etc. in chipping stone or wood with iron chisel it is usually chip of chisel or hammer which causes injury. Size and velocity of missile is important. damage due to:
Entry of Foreign body: It is through cornea or sclera but wound of entry may be very small and heal spontaneously. It may remain in anterior chamber angle and get hidden by scleral edge and can be seen only on gonioscopy. It may get embedded in the iris. If it has passed through iris, hole in iris will be seen. It may pass through circumlental space without touching the lens and gets lodged in vitreous or retina. Rarely it pierces retina choroid and sclera and comes to orbital tissue (double perforation) tract of F.B. in vitreous is seen as grey line. It causes exudation necrosis and fibrous tissue proliferation in retina. A foreign body bigger than 2 mm usually affects vision but smaller than that if removed early may not affect vision significantly. Due to fibrosis the F.B. gets encapsulated. Foreign body lodged in the lens causes cataract and can be surgically removed like cataract extraction.
- Mechanical effect as with large sized foreign body
- Introduction of infection – If unclean foreign body with lots of dirt and particulate matter on it.
- By specific action: By chemical reaction as with retained iron or copper foreign bodies.
Infection: Lens and vitreous provide excellent culture media and hence suppurative infection is frequent. Even gas gangrene and tetanus are reported. Early active antibiotic therapy preferably intra venous and local route are given to prevent it, because if it develops visual prognosis is poor.
Specific action: Glass, plastic and porcelain, inert metals like gold, silver, platinum and tantalum, all these are not associated with chemical reaction. Lead and alluminium excite mild local reaction. Zinc, nickel and mercury tend to excite suppurative reaction. Iron and copper the 2 most common material undergo electrolytic dissociation and are widely deposited throughout eye causing degenerative changes.
Siderosis: Retained iron and steel (depending on ferrous content) causes it. Ferrous ion disseminates and combines with cellular proteins thus killing the cells and causing atrophy . Earliest is deposit in ant. capsular cells of lens where oval patches of rusty deposit are arranged radically in a ring corresponding with edge of pupil. Iris gets stained reddish brown, retinal degeneration with pigmentary retinopathy and attenuation of blood vessels occur. Chronic secondary glaucoma due to deposits in trabecular meshwork.
Chalcosis: Pure copper gives violent suppurative reaction with fibrosis and shrinkage of globe, but alloys give milder reaction resulting in chalcosis. It becomes electrolytically dissociated with deposition when migration is resisted. Typical sites are cornea, golden brown Kayser Fleisher ring. Under capsule of lens brilliant golden green sheen radiating like petals of a flower (sunflower cataract) and retina at posterior pole where lustrous golden plaques reflect the light with metallic sheen. As there is no cellular death as with iron, vision may remain good as no degeneration.
Non Specific Action: Organised materials (wood and other vegetable matter produce reaction with leucocytic and giant cell infiltration and inflammation. Ophthalmia Nodosa severe iridocyclitis, with granulomatous nodules embedding caterpillar hair may be formed. Intra Ocular Cyst: Due to proliferation of the epithelium of the hair roots if eye lashes are carried into anterior chamber.
Diagnosis: Very important as patient is often unaware that an F.B. has entered the eye in all suspected cases, careful search for wound of entry or its scar or presence of hole in iris or tract in lens and vitreous must be thoroughly made with slit lamp. Ultra sonography B Scan will reveal presence of F.B. and site. X-ray with localiser applied to cornea, with eye looking straight, up and down in anteroposterior and lateral view help to detect site and size .Bone free radiography with dental film are also helpful. C.T.Scan and MRI particularly in war injuries where multiple ocular orbital and intracranial F.B. may be present. Treatment depend on whether it is magnetic or non magnetic 90% are iron and magnetic which can be removed with electro magnet taking incision over the site of foreign body. If in anterior chamber or iris can be removed by incision at limbus with wash or forceps. Non magnetic foreign body needs pars planar vitrectomy and removal with crocodile forceps
Orbital F.B.: After localization exploration is done at appropriate site and removed with forceps. In case of magnetic foreign body electromagnet can be utilized.
Sympathetic Ophthalmitis: It results from a perforating wound in ciliary body region- It is frequent if iris lens or ciliary body are incarcerated in the wound. It can occur at any age but children are more susceptible. Sever plastic Iridocyclitis occurs in non injured eye. Patient complaints on photophobia and lacrimation or decreased vision for near due to weakness of accommodation (Sympathetic irritation). Must immediately look for K.P.s and flare with slit lamp. If not treated immediately, it develops iridocyclitis, choroiditis, secondary glaucoma , ciliary shut down and atrophic
bulbi leading to painful blind eye. Treatment is by local and systemic steroids and local atropine. Prevention is better than cure and hence early appropriate management of injured eye must be done.