Causes and visual outcomes of perforating ocular injuries among Ethiopian patients

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Introduction

Ocular trauma, in particular open globe injury, is an important cause of monocular visual impairment and blindness in the younger and economically active age group.¹ Besides loss of vision, earnings (job opportunities) and productivity, it increases the cost to society because of increased healthcare spending.

Although it affects all age groups, previous reports have indicated that ocular trauma victims are predominantly males and young, with the majority under 30 years of age. In those between 20 and 44 years of age, injuries account for 10% of incident bilateral blindness.¹

The magnitude of ocular injuries in our country has not been studied previously. This review was conducted to assess the magnitude, causes and visual outcomes of ocular trauma cases at Menelik II Hospital in Addis Ababa.

Patients and methods

All patients with open globe injury who were operated on at the Department of Ophthalmology, Faculty of Medicine of Addis Ababa University, Menelik II Hospital, Addis Ababa over a one year period (January 1998 – December 1998) were reviewed.

The chart numbers of patients with open globe injury were obtained from the registry book of the major operating room. In addition to those obtained from the operating room registry book, data such as cause, date and duration of injury, visual acuity, type and extent of injury, medical treatment given before surgery, and profession of the patient were documented.

Finally, analysis was made as to the age and sex distribution, post-operative complications, visual outcome of open globe injury and duration of follow-up. The patient was categorised as monocular blind if the visual acuity of the injured eye was less than 3/60 (or counting fingers (CF) at less than 3 metres). However, the new standardised ocular trauma classification 2 was not applied and as a result was not used in this analysis.

Results

Table 1. Age and sex distribution of cases with ocular injury

Table 2. Causes of injury

Table 3. Anatomy of eye injuries

Table 4. Pre-operative and post-operative visual status of the eyes

Two hundred and four patients with perforating ocular injuries underwent surgery during the study period. All had injury to only one eye. Of the total eye operations done in the major operating room during the study period, 8.4% were due to perforating ocular injury. Male patients were three times the number of females, as shown in Table 1. The age ranged between 1.5 and 65 years, with the average being 19.4 years. One hundred and fifty-four (75.5%) patients were aged 30 years or under.

The most common causes of perforating ocular injuries were wood, metal and stone objects in 67 (32.8%), 58 (28.4%) and 29 (14.2%) respectively (Table 2). Most of the injuries occurred during chopping or cutting wood, hammering metals or nails and carving stone. These are associated with professions such as farming, garage work and carpentry in adults. Children, on the other hand, mostly sustained accidental injuries by rubber bands, needles, pencils, etc. while playing with others.

In the majority of cases, 151 (74%), the cornea was involved either alone (40 cases) or in association with the lens (88 cases) or the sclera (23 cases), as seen in Table 3. Twenty patients (9.8%) were too young to have their visual acuity taken. Of the remaining 184 patients, 165 (89.7%) had pre-operative visual acuity recorded as blind in the involved eye (Table 4). Post-operatively, 141 (76.6%) cases had visual acuities of less than 3/60 (CF < 3 metres). Thirty-nine (19.1%) cases with ruptured globe were eviscerated.

Discussion

A hospital based study³ has revealed that severe injuries such as ruptured globe, intraocular foreign bodies, hyphaema and orbital or facial fractures constitute about 5% of all ocular trauma cases. In this study, only perforating ocular injuries were looked at rather than the whole spectrum of eye trauma cases. However, ocular injury cases constituted 8.4% of all ocular operations performed in the major operating room during the study period.

Although it affects all age groups, previous reports have indicated that ocular trauma victims are predominately young with a majority under 30 years of age. Males greatly outnumber females as victims of eye injuries with a male to female ratio ranging from 3:1 to 12:14,³ and the greatest number of eye injuries occurred in school-age children.⁶ Our results were in agreement with this trend as 75.5% of the cases were males and 75.5% were also aged 30 years or under.

York-related injuries are described as the commonest cause of ocular trauma among adults.^3,5 On the other hand, the most common cause of paediatric injuries were accidental blows and falls. Industrial injury to the eye is rare in our country, and here the major causes were related to farming, carpentry or garage work.

The visual outcome of perforating ocular injuries depends on the type of trauma sustained. Injuries from sharp objects have a better prognosis compared with those caused by blunt objects. This is because sharp objects cause laceration with damage confined to the underlying tissue whereas those caused by blunt objects result in widespread damage which, in the case of sufficiently high force, may rupture the globe.

The severity of trauma is also among the prognostic factors used to predict the final visual outcome. Injuries associated with a wound 4mm or longer, combined anterior and posterior segment injuries,³ lens dislocation, vitreous haemorrhage, intraocular foreign bodies, scleral wounds and afferent pupillary defect ⁷ were found to have poor prognoses. In this retrospective review, the severity of injury was difficult to ascertain.

Previous studies ^5,7,8have indicated that an initial visual acuity of the traumatised eye has a predictive value in regard to the final visual outcome. They showed that initial visual acuity of 5/200 (1.5/60) or better was associated with a favourable prognosis.

The management of ocular injury seeks to restore the anatomy and function of the eye to its pre-injury state. Visual rehabilitation of the injured eye often requires the involvement of several sub-specialists. Diagnostic means such as ultrasonography and radiography need to be readily available with trained personnel.

About 2/3 of our patients remained blind in the injured eye. This was due to failure to manage the complications of injury. We do not have trained personnel in corneal transplantation. We also lack a vitreo-retinal surgeon to manage vision threatening posterior segment injury such as vitreous haemorrhage or retinal detachment. In our cases, 89.7% were blind before surgery as opposed to 76.6% after surgery to the injured eye. The improvement in the visual acuity of some patients was due to cataract extraction with lens implantation performed in these cases.

The Department is a tertiary centre where patients are referred for better management. Efforts must be made to strengthen the capacity of the Department to handle perforating ocular injury cases appropriately.

References

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2 Kuhn F, Morris R, Witherspoon C D, et al. A standardized classification of ocular trauma. Ophthalmology 1996; 103: 240-243.

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4 Eagling E M. Perforating injuries of the eye. Br J Ophthalmol 1976; 60: 732-736.

5 Quah B L, Yeo Y S I, Ang C L. A retrospective study of open globe injuries seen at Singapore National Eye Centre (SNEC) in 1995. Asia-Pacific Journal of Ophthalmology 1997; 9(2): 18-23.

6 Strahlman E, Elman M, Daub E, Baker S. Causes of pediatric eye injuries: A population based study. Arch Ophthalmol 1990; 108(4): 603-606.

7 Juan E D, Sternberg P, Michels R G. Penetrating ocular injuries: Types of injuries and visual results. Ophthalmology 1983; 90(11): 1318-1322.

8 Williams D F, Mieler W F, Abrams G W, Lewis H. Results and prognostic factors in penetrating ocular injuries with retained intraocular foreign bodies. Ophthalmology 1988; 95(7): 911-916.