Ocular Trauma PDF

 Contents General principles: Initial assessment, Investigations. Blunt trauma: - Anterior segment complications: Corneal abrasion, Hyphema, traumatic mydriasis, Iridodialysis, Ciliary body, cataract. - Posterior segment complications: posterior v...

 Contents General principles: Initial assessment, Investigations. Blunt trauma: - Anterior segment complications: Corneal abrasion, Hyphema, traumatic mydriasis, Iridodialysis, Ciliary body, cataract. - Posterior segment complications: posterior vitreous detachment, Commotio retinae, Choroidal rupture, Retinal break, Optic neuropathy, Optic nerve avulsion. Traumatic foreign body (Penetrating & Perforating) Evaluation & Management Posterior Segment Manifestations of Trauma - Closed globe injuries: Contusion, Lamellar laceration, superficial foreign bodies. - Open globe injuries: Scleral Rupture, Laceration, IOFB: penetrating or perforating, posttraumatic endophthalmitis, Retained IOFB (chalcosis, siderosis), sympathetic ophthalmitis, blow-out floor fracture.  Ocular Trauma General principles of management: 1. Initial assessment: Determine any life-threatening problems, and general condition should be stabilized. History: circumstances, timing and likely object. Thorough examination of both eyes and orbits. 2. Special investigations: Plain radiographs: when a foreign body is suspected, to localize it and plan for the surgery. CT: superior to plain x ray in detection and localization of intraorbital foreign body. It is also used in determining the integrity of intracranial, facial and intraocular structures. *MRI should never be performed if a metallic foreign body is suspected as this may induce more trauma and damage by it’s movement again. US: detection of intraorbital foreign body, globe rupture (as the rupture may be posteriorly hidden), retinal detachment. Electrophysiological tests (VEP, EOG, ERG)* in assessing the integrity of the optic nerve and retina. *Visually evoked potential, Electro-oculogram, Electroretinogram  Blunt Trauma Causes: squash balls, luggage straps and champagne corks. Complications: 1- Anterior segment complications: Corneal abrasion: epithelial loss, which stains with fluorescein. Rx: pressure bandage for 24-48 h. Hyphaema: hemorrhage in the anterior chamber usually occurs in children and young persons. The source of bleeding is the iris or ciliary body. Secondary bleeding can occur during the first week and is more serious than initial bleeding. ‣ It may cause secondary glaucoma by three ways: through occluding of the trabecular meshwork by blood cells and proteins, or by pupillary block or by the associated iritis and its complications e.g. anterior and posterior synechiae. ‣ Corneal staining (haemosiderosis) can occurs duo to persistent hyphaema specially if associated with rising IOP. It is due to deposition of iron on corneal endothelium which leads to severe affection of visual acuity where penetrating keratoplasty indicated. ‣ If hyphaema fills more than half of the anterior chamber, the patient should be admitted to hospital with complete bed rest. If it is mild and fills less than half of the anterior chamber, the patient is discharged but with complete bed rest in home. Bed rest is important step in treatment of hyphaema to avoid secondary bleeding.  Traumatic mydriasis: it is often permanent due to damage to the iris sphincter muscles. Permanent large mydriasis lead to photophobia and blurred vision. Iridodialysis: is a dehiscence of the iris from the ciliary body at its root. Usually the pupil has a D shape and the vertical part of D is toward the dehiscent. It is innocuous and asymptomatic or occasionally can cause monocular diplopia (2 pupils). Ciliary body: ‣ Ciliary shock (ocular hypotonia). ‣ Anterior chamber angle recession: recession of the angle between the periphery of the iris and anterior face of ciliary body, which seen by gonioscopy. Angle recession per se is an innocuous thing, but may indicate severe trauma and associated with damage to the trabecular meshwork that may cause "Angle recession glaucoma". This type of secondary glaucoma might occur after months or even a long time (years). Lens: cataract. 2- Posterior segment complications: Posterior Vitreous Detachment (PVD): it may be associated with vitreous hemorrhage, retinal tear and pigment cells similar to tobacco dust, which are seen floating in the anterior vitreous. Commotio retinae: concussion of the sensory retina resulting in cloudy swelling area of retina due to damage of inner part of blood retinal barrier. If the oedema is persists and involving the macula, it will cause cystoid macular edema (CME) and permanent diminish VA. Choroidal rupture. Retinal break: tears and holes. Retinal dialysis: dis insertion of part of the extreme periphery of sensory retina from its attachment to the non-pigmented epithelium of ciliary body. Optic neuropathy: is an uncommon but often devastating cause of permanent visual loss. Optic nerve avulsion: is rare and typically occurs when an object intrudes between the globe and the orbital wall, displacing the eye.  Penetrating and Perforating Ocular Trauma It is important to understand the difference between a penetrating wound and a perforating wound for accurate communication and documentation. In a penetrating wound, a foreign body passes into an anatomical structure; in a perforating wound, a foreign body passes through such a structure. Conjunctival Laceration: When managing conjunctival lacerations associated with trauma, the physician must be certain that the deeper structures of the eye have not been damaged and that no foreign body is present. ‣ In general, small linear conjunctival lacerations do not need to be sutured. However, stellate conjunctival lacerations, lacerations with bare sclera exposed, or lacerations with lost or retracted conjunctival tissue will heal faster if sutured closed. Conjunctival Foreign Body: removal, topical antibiotics.  Corneal Abrasion: Disruption of the corneal epithelium is usually associated with immediate pain, foreign-body sensation, tearing, and discomfort with blinking. ‣ Pressure patching can relieve pain from an abrasion by immobilizing the upper eyelid to prevent rubbing against the corneal defect, although patching is not necessary for most abrasions and some patients may find patches uncomfortable. Topical antibiotic ointment is suggested in either case. Another alternative is a bandage contact lens, which provides pain relief and facilitates reepithelialization. Antibiotic drops rather than ointment should be used with a bandage lens. Corneal Foreign Body: if it is superficial should be removed and topical antibiotic is suggested.  Evaluation & Management of Perforating Ocular Trauma History: Metal-on-metal strike, high-velocity projectile, high-energy impact on globe, sharp injuring object? When exactly did the injury occur? What was the exact mechanism of injury? How forceful was the injury? Was there any object that may have penetrated the eye; if so, what was the object’s material (wood stick, nail, knife, etc.)? Was the injury work-related? Was the patient hammering metal on metal or working near machinery that could have caused a projectile to enter the eye? Was the patient wearing spectacles or was he or she close to shattered glass? Was the patient wearing eye protection? What was the health status of the eye before the injury? Has the patient had previous ocular surgery, including LASIK, penetrating keratoplasty, or cataract surgery? Are there concomitant systemic injuries? What emergency measures were taken, if any (eg, tetanus shot given, antibiotics administered)? When was the last tetanus toxoid administered? When was the patient’s last oral intake (in case surgery is required)? Examination: A complete general and ophthalmic examination. As soon as possible, the examiner should determine and record visual acuity, which is the most reliable predictor of final visual outcome in traumatized eyes. Pupillary examination should be performed to detect the presence of an afferent pupillary defect (including a reverse Marcus Gunn response) arising from the possibility of traumatic mydriasis. The examiner should then look for key signs that are suggestive or diagnostic of a penetrating or perforating ocular injury. Surgical (Preoperative) Management: If surgical repair is required, the timing of the operation is crucial. Although studies have not documented any disadvantage in delaying the repair of an open globe for up to 36 hours, intervention ideally should occur as soon as possible. Prompt closure of the wound to restore the integrity of the globe helps minimize the risk of additional damage to intraocular contents, inflammation, microbial proliferation, and endophthalmitis. The following should be done before proceeding to the operating room: apply a protective shield avoid interventions that require prying open the eyelids ensure that the patient has no food or liquids prescribe appropriate medications for sedation and pain control initiate intravenous antibiotics and antiemetics provide tetanus prophylaxis seek anesthesia consultation  Posterior Segment Manifestations of Trauma Ocular trauma is an important cause of visual impairment worldwide. Ocular globe trauma can be classified as follows (terminology based on the Birmingham Eye Trauma Terminology System): Closed globe injuries ‣ Contusion (blunt trauma without break in eye wall) ‣ Lamellar laceration (partial thickness wound of the eye wall) ‣ Superficial foreign bodies Open globe injuries ‣ Rupture (blunt trauma with break in eye wall) ‣ Laceration (full thickness wound of the eye wall, caused by a sharp object) ‣ Intraocular foreign bodies, penetrating or perforating: Penetrating injury (entrance break; no exit break in eye wall) Perforating injury (both entrance and exit breaks in eye wall)  Blunt Trauma Without Break in Eye Wall In blunt trauma, the object does not penetrate the eye but may cause rupture of the eye wall. Serious sequelae from blunt trauma affecting the anterior segment include: Angle recesygsion recession Iridodialysis Iritis Hyphema Subluxated or dislocated lens Serious sequelae from blunt trauma affecting the posterior segment include: Commotio retinae Choroidal rupture Macular hole Choroidal hemorrhage Retinal tears or detachment Vitreous hemorrhage Traumatic chorioretinal disruption (retinnal sclopetaria)  Open-Globe Injuries Scleral Rupture: Important diagnostic signs of rupture include a marked decrease in ocular ductions, very boggy conjunctival chemosis with hemorrhage (ecchymosis), deepened anterior chamber, and severe vitreous hemorrhage. Intraocular Foreign Bodies (IOFB): should always be suspected and ruled out in cases of ocular or orbital trauma. Posttraumatic Endophthalmitis: Inflammation of all intraocular structures except the sclera, but if inflammation involves the sclera it is called "Panophthalmitis". Endophthalmitis occurs following 2%–7% of penetrating injuries; the incidence is higher in association with IOFBs and in rural settings. Posttraumatic endophthalmitis can progress rapidly; its clinical signs include marked inflammation featuring hypopyon, fibrin, vitreous infiltration, and corneal opacification.  Retained intraocular foreign bodies: The reaction of the eye to a retained foreign body varies widely and depends on the object’s chemical composition, sterility, and location. Inert, sterile foreign bodies such as stone, sand, glass, porcelain, plastic, and cilia are generally well tolerated. If such material is found several days after the injury and does not appear to create an inflammatory reaction, it may be left in place, provided it is not obstructing vision. Zinc, aluminum, copper, and iron are metals that are commonly reactive in the eye. Of these, zinc and aluminum tend to cause minimal inflammation and may become encapsulated. However, any very large foreign body may incite inflammation and thereby cause proliferative vitreoretinopathy. Chalcosis: Pure copper is especially toxic and causes acute chalcosis. Prompt removal is required to prevent severe inflammation that may lead to loss of the eye. Foreign bodies with a copper content of less than 85% (eg, brass, bronze) may cause chronic chalcosis. Typical findings in chronic chalcosis are deposits in Descemet membrane (a sign similar to the Kayser Fleischer ring in Wilson disease and the result of copper’s affinity for basement membranes), greenish aqueous particles, green discolouration of the iris, lens capsule (“sunflower” cataract), brownish red vitreous opacities and strand formation, and metallic flecks on retinal vessels and the internal limiting membrane in the macular region. Late removal of copper may not cure the chalcosis; in fact, dissemination of the metal during surgery may worsen the inflammatory response. Siderosis bulbi: iron from IOFBs is deposited primarily in neuroepithelial tissues such as the iris sphincter and dilator muscles, the nonpigmented ciliary epithelium, the lens epithelium, the retina, and the RPE. Retinal photoreceptors and RPE cells are especially susceptible to damage from iron. Electroretinography (ERG) changes in eyes with early siderosis include an increased a-wave and normal b-wave, a progressively diminishing b-wave amplitude over time, and eventually an undetectable signal during the final stage of iron toxicity of the retina. Serial ERGs can be helpful in monitoring eyes with small retained foreign bodies. If the b-wave amplitude decreases, removal of the foreign body is generally recommended. Enucleation (excision of the eyeball): Primary enucleation: should be performed only for severe injuries, with no prospect of retention of vision when it is impossible to repair the sclera. Secondary enucleation: may be considered following primary repair if the eye is severely and irreversibly damaged, particularly if it is also unsightly and uncomfortable. It has been recommended that enucleation should be performed within 10 days of the original injury in order to prevent the very remote possibility of sympathetic ophthalmitis. Sympathetic Ophthalmitis: It is a very rare, bilateral, granulomatous panuveitis which occurs after open ocular injuries usually associated with uveal prolapse or less frequently following intraocular surgery, when the uveal tissue came in contact with conjunctiva. It occurs due to antibody formation against the uveal tract lead to severe immunological inflammation of the injured eye and the fellow eye. The traumatized eye is referred to as the "exciting eye", and the fellow eye, which also develop uveitis, is called "Sympathizing eye". Blow-out floor fracture: It is typically caused by sudden increase in the orbital pressure by a striking object such as a fist or tennis ball. Since the bones of the lateral wall and roof are usually able to withstand such trauma, the fracture most frequently involves the floor and occasionally, the medial orbital wall may also be fractured by such type of trauma. Signs: Periocular signs: include ecchymosis, oedema and subcutaneous emphysema. Infraorbtal nerve anesthesia: involving the lower lid, cheek, side of the nose, upper lip, upper teeth and gums. Vertical diplopia: happens due to: ‣ Hemorrhage and oedema of the orbit restricting the movements of the globe. ‣ Mechanical entrapment of the inferior rectus or inferior oblique muscle or both within the fracture. ‣ Direct extraocular muscle injury.