Penetrating Eye Injuries PDF

Some penetrating eye injuries (PEIs) are very obvious, but in many cases the diagnosis may be missed unless the examining doctor maintains a high index of suspicion. Once the diagnosis is made, it is most important that subsequent actions do not make the situation worse. Included in this document...

Some penetrating eye injuries (PEIs) are very obvious, but in many cases the diagnosis may be missed unless the examining doctor maintains a high index of suspicion. Once the diagnosis is made, it is most important that subsequent actions do not make the situation worse. Included in this document History Examination Management Key points History Suspect a penetrating injury in every case of ocular trauma. As in all trauma, it is very important to question the patient carefully in order to ascertain exactly what happened. You need to be very specific in your questioning. Firstly, what exactly was the patient doing? Hammering and using high speed tools are very dangerous activities that often result in an intraocular foreign body (IOFB). Was the patient hammering metal on metal? Did they note a piece of the hammer/chisel/part of the car etc was missing (and thus possibly in the eye)? Were they using high pressure water, air or oil hoses? Were there any high speed tools such as drills, disc grinders or lathes involved? Was there any workmate nearby using any such device? Did anything fall into the eye (and from what height) or was the patient pulling on anything? Were they cutting a piece of wire and were both ends present after the injury? Ascertain whether the patient was wearing any safety spectacles or normal glasses at the time and whether they were broken or damaged. Shattered spectacles can easily lacerate the eye. Secondly, what exactly did the patient experience? Floaters are a very sinister symptom; they usually herald an intraocular haemorrhage. Typically patients report that soon after something struck the eye they noted a ‘blob’, ‘spot’ or ‘thread’ obstructing their vision. Likewise photopsia (flashing lights) is a sinister symptom that suggests either direct retinal trauma or vitreoretinal traction produced by an IOFB. Pain is not that specific as small objects travelling at high speed can enter the eye with minimal pain. Normal vision can be misleading for similar reasons. Examination The examination must balance the need to gather as much information as possible and avoiding any further damage. Essentially, if you come across clear evidence of a penetrating injury (Fig. 1) stop the examination. When the history suggests that a penetrating injury could have occurred, the examination is aimed at excluding such an event. If the history gives a clear indication that a penetrating injury has, or could have occurred, the examination is largely academic. For example if a mechanic was hammering a wheel bearing and felt something enter his eye, he has an IOFB until proved otherwise and needs ophthalmic review. Fig. 1. This patient has an obvious penetrating injury; a piece of wire is lodged in the sclera. NO ATTEMPT should be made to remove such foreign bodies due to the possibility of causing further damage. (Courtesy Dr D. Magauran) Lid lacerations and bleeding from the eye Suspect a penetrating injury in every patient with a lid laceration. Bleeding coming from under the eyelid is usually due to a significant injury to the eye NOT the eyelid; the blood comes from the iris or ciliary body. Vision If there is an obvious PEI don't spend too much time on the vision, and don't try testing the vision with a pinhole as there is a risk that the manoeuvre may cause more trauma. If there is no obvious PEI, testing the vision and pinhole vision are mandatory. A patient with normal vision can have a very small penetrating injury and even an IOFB, but it is a relatively reassuring sign. Subconjunctival haemorrhage The classical teaching is that a penetrating injury is likely if there is a subconjunctival haemorrhage that has no visible posterior limit. This is true, but even small haemorrhages can herald and mask a PEI. Therefore, it is safer to say that if a patient has a subconjunctival haemorrhage following trauma and the nature of the trauma is likely to lead to a penetrating injury, the patient has a penetrating injury until proven otherwise. For example, a patient with a small subconjunctival haemorrhage who was struck in the eye with a piece of wire should be referred for ophthalmic review. Subconjunctival pigment Uveal (choroid, ciliary body, iris) pigment can escape through a scleral laceration and lie under the conjunctiva. The pigment is dark brown in both blue and brown-eyed patients. It is a very sinister sign. Irregularity of the pupil Abnormalities of the shape of the pupil are usually due to iris trauma. In PEIs this can be due to either damage to the iris (in particular the sphincter) or prolapse of the iris into a wound (Fig. 2) Fig. 2. Iris prolapse. The pupil is peaked because the peripheral iris has prolapsed out of the eye through a corneal laceration. Abnormal red reflex Look carefully for an extra red reflex (Fig. 3), which alerts the examiner that an intraocular foreign body has passed through the iris. Any irregularity of the red reflex should ring ‘alarm bells’; it suggests traumatic cataract, intraocular haemorrhage, an IOFB or a retinal detachment. Small metal fragments often lodge in the lens and can be easily seen against the red reflex (Fig. 4). The Seidel test Seidel's test assesses whether aqueous is leaking from the anterior chamber into the tear film via a corneal laceration. Fluorescein is instilled into the tears. Leaking aqueous appears as a spreading dark ‘oil-slick’ in the green fluorecein-stained tears. Dilated fundus exam If there is no obvious injury, dilate the pupil with tropicamide 0.5% or cyclopentolate 1%. (If there is an obvious penetrating injury, leave the fundus examination to an ophthalmologist). Check for the presence of any IOFB (Fig. 5), vitreous haemorrhage or a retinal haemorrhage. Fig. 3. Second red reflex. This patient Fig. 4. Metallic foreign body Fig. 5. A large shard of metal located was referred by a GP who noted a in the lens, as seen against in the vitreous. second red reflex when examining with the red reflex their ophthalmoscope. A small piece of metal had entered the eye through the peripheral cornea and passed through the iris before finally settling in the posterior segment. Management Primum non nocere The key issue is to do no harm. If there is any suspicion from the history or examination that the eye has sustained a penetrating injury DO NOT examine the eye further. Attempts to open a closed eye may case further damage. NEVER attempt to remove any penetrating foreign body. The use of X-ray In general there is little point in GPs X-raying patients with a suspected IOFB. If the history and/or examination are suggestive of an IOFB, then the patient needs review by a specialist. Many IOFBs not easily seen by GPs can be seen by ophthalmologists and visualisation supercedes radiology. Occasionally, a screening X-ray does pick up an unsuspected metallic foreign body, but it also misses all non-metallic and some metallic foreign bodies. CT is the preferred way to image foreign bodies in the eye. Discuss the case with an ophthalmologist  If at all concerned, talk to an ophthalmologist. In most cases where penetration and/or an IOFB are possible they will want to see the patient. Penetrating injuries are ocular emergencies. Protect the eye from further damage Place a SHIELD over the eye, NOT A PAD. Pads apply pressure to the eye and can lead to loss of intraocular contents. Do not try to instil any eye drops or ointments as these can enter an open wound, and any movement or squeezing during instillation can also result in further damage to the eye. An excellent makeshift shield can be constructed by cutting off the bottom of a paper cup. Key points Maintain a high degree of suspicion. Check for any history of hammering or the use of high speed tools. Don't make the situation worse by forcibly examining the eye, instilling drugs or padding the eye. Don’t pull foreign bodies out of the eye. If in doubt discuss the case with an ophthalmologist. © GP Eyes - Dr Malcolm McKellar 2011