Ultrasonography and ocular trauma [abstract]

Blunt or perforating trauma can cause considerable damage to both the anterior and posterior segment of the eye. Since the media are often opaque following trauma, the extent of the damage may be difficult to assess with routine examination. Ultrasonography can reveal hidden pathology and is often helpful in deciding upon the proper line of treatmemt. In post-contusional trauma without an open globe, full ultrasonographic investigation, including immersion techniques, can be performed. On the contrary, after perforation lesions, an exploratory B-scan can be used for locating an intraocular foreign body in addition to gross assessment of the damage. The ultrasonographic examination can only be continued in further detail after primary closure of the wound. When an x-ray of the orbit reveals the presence of an intraocular foreign body B-mode ultrasonography is superior to the Comberg-Pfeiffer method and computer tomography for precise localizations of the object and for detection of collateral damage. Transpalpebral echography or scans with the probe directly applied to the eye, at significantly reduced sensitivity levels (-20 or -30 dB) are the methods of choice for tracing a foreign body in the posterior segment or orbit. Lowering the sensitivity settings will also improve the accurate location of the foreign body. The immersion technique is used when the foreign body is located anteriorly in the eye, providing that the entry wound is closed. In particular after contusional injuries, ultrasound biomicroscopy (UBM) can be used for detailed observations of the cornea, anterior lens, chamber angle and ciliary body. Recession of the angle, subluxation of the lens and dialysis of the iris or ciliary body can be diagnosed with relative ease. When vitrectomy is indicated either as a primary or secondary procedure following ocular trauma, ultrasonography is essential in the preoperative evaluation. It will help in deciding upon the length of the preoperative period, the estimated duration of the operation and the appropriate surgical approach. A full anatomical analysis can be obtained by systemically assessing the biometric, topographic, kinetic and quantitative characteristics of the various parts of the eyes. The most commonly occuring ocular pathology following trauma, along with the most suitable diagnostic ultrasonic techniques will be discussed in detail and are depicted in the table. (AU)

Posterior Segment Trauma

Posterior segment trauma continues to be a significant cause of visual disability in Trinidad and Tobago. The pattern of injury has changed over the last ten years. Since the introduction of the seat-belt ordinance of 1995, there has been a decrease of macerated eyes resulting from windscreen contact. Air bags have probably also played a protective role. The majority of posterior segment trauma now comes from sporting activities and a small number from the industrial work place. New vitreo retinal techniques, including videoendoscopy have increased the ability to salvage vision in these eyes.(AU)

Anterior Segment Trauma

Ocular is a leading cause of preventable blindness in developing countries. The trauma may involve the adnexae, anterior segment and/or posterior segment. This presentation will be confined to the anterior segment injury which may be caused by chemicals, blunt or sharp objects. The examination and treatment, both medical and surgical, of these injuries will be discussed. Emphasis will be placed on prevention especially in children, and industrial workers. Education of paramount immportance in reducing blindness due to trauma.(AU)

Management of orbital and adnexal trauma

Ocular adnexal trauma involve the eyelids, orbit, or lachrymal system. Management of complex orbital and ocular adnexal trauma should involve a multidiscplinary approach. Life-and-sight-threatening injuries must be recognised and treated appropriately. Adherence to the fundamentals of trauma management and a stepwise, systemic approach to ocular and adnexal examination reduce the likelihood that serious injuries will be missed. After all injuries have been identified, they should be repaired appropriately to optimize both functional and cosmetic outcomes.(AU)

The management of ocular trauma in the West Indies

Ocular trauma is a common occurence in the West Indies. 22 percent of cases seen in the eye clinic at the University Hospital of the West Indies in 1988 and 18 percent of the surgical cases treated at the Kingston Public Hospital between 1988 and 1992 were due to trauma. Competent management of ocular trauma must be a major consideration in the West Indies. Prevention must be paramount in the strategy of management. The use of seat belts in motor vehicles and of safety glasses in industrial settings is of obvious importance. Less obvious but probably of equal importance is the use of ophthalmic protection around the home, or by the occassional user of hammers, power equipment, drills, chisels, lawn mowers and other implements or equipment. Prevention is so fundamental that it is often taken for granted and inadvertently omitted in reviews like this, with the discussion beginning with the management of the injury itself. In cases of blunt injury hyphaema, a sickle test must be done, as sicklers are more susceptible to the effects of intraocular pressure (IOP) and may suffer these with even small hyphaemas. Dehydration should be avoided, especially if carbonic anhydrase inhibitors are to be used. The IOP should be monitored and anterior chamber washout should be done if it remains above 25 mm Hg. Care should be taken to avoid direct surgical trauma to the lens, but gentle touch need not be feared. The examination of the peripheral fundus must be done as soon as it is comfortable for the patient in order to detect tears of the retina before they lead to retinal detachment. Long-term follow up (yearly checks) should be done to detect post-traumatic glaucoma, as this is sometimes seen as long as 20 to 30 years after the injury. The use of epsilonaminocaproic acid to decrease the incidence of re-bleeding is standard practice in North America, although it is not widely used in Jamaica. Serious penetrating injuries are treated surgically. The goal of surgery is the anatomical restoration as close as possible to normal in order to obtain restoration of physiological function. The objectives of primary repair are: accurate repair of lacerations, removal of any foreign body, and the prevention of infection and long term complications. The management of vitreous deserves special mention. Vitreous in the wound must be removed by localized vitrectomy with the avoidance of vitreous traction. This is facilitated by the use of a vitrectomy device.(AU)

Mycetoma of the palpebral conjunctiva caused by allescheria boydii (monosporium apiospermum)

Mycetoma of the left upper palpebral conjunctiva due to allescheria boydii is reported in a 44-year-old male Negro gardener. The infection was associated with symblepharon and corneal scarring. This appears to be the fourth reported case of mycotic infection of the eye caused by allescheria boydii and the first in which the organism had produced a mycetoma of the conjunctiva (AU)

Mechanical injuries to the eye

This is a brief description of the common causes of mechanical injury to the eye. The diagnosis and early treatment are discussed (AU)