Blast injuries of the eye in Ethiopia
First published in Tropical Doctor 1993; 23: 76-8. Reproduced by kind permission
Ninety-four cases of ocular blast injuries (122 eyes) were studied. Sixty-five percent of the cases were between 15 and 25 years of age. The right and the left eyes were involved in 38% and 32% of the cases, respectively, while bilateral involvement was seen in 30%. Ninety of the eyes (74%) were blind. Twenty-one per cent of the patients with binocular injuries had bilateral blindness. Injuries of the iris, conjunctival and corneal foreign-bodies, and corneal and/or scleral lacerations were the most frequent types of injury seen.
Duke Elder states that explosive injuries to the eye do occur in civilians but they are more common in war, when they are most usually caused by the bursting of shells, bombs, grenades or buried mines.1The eyeball measures 1/375 of the total body surface area and only 0.1% of the erect frontal silhouette.2Despite this very small area of exposure, ocular blast injuries are seen in civilians3,6and soldiers. The damage is usually due to fragmentations that cause penetrating injuries and to the explosive force that causes concussion of the eyeball.7,8The fragments may come from the explosive itself or from the environment. The extent of injury from these penetrating fragments varies according to their size and velocity, the depth of penetration and the site of impact.8
This article will focus on the distribution of the injuries by age, their laterality (if any), the visual outcomes and the common types of ocular injuries.
Patients and methods
A total of 94 cases of ocular blast injuries seen over a period of 4 months in 1988 were taken for the study. All the casualties were from the Tigray front (Northern Ethiopia).
The patients were admitted to Menelik II Hospital in Addis Ababa. Some of them had undergone ocular surgery in Asmara before they were sent to Menelik II Hospital. Such patients had referral letters, brought along with them; which included the cause of injury, major types of ocular injury seen and the operative procedure(s) carried out.
On admission to Menelik II Hospital, the relevant history was taken and visual acuity (V/A) was recorded using the E-chart. The eyes were examined with the slit lamp microscope, the Goldmann contact lens (where possible), and by direct and/or indirect ophthalmoscopy. The intraocular pressure (IOP) was measured, where indicated, with the Schiotz tonometer. Best corrected V/As were taken at different intervals during hospitalisation and those measurements taken at or about the time of discharge were taken for the study. Radiological studies were only done in those cases where penetrating injuries were suspected.
Blindness is defined as V/A of less than 3/60.12The Z-test was used in the analysis for statistical significance.
There were, in total, 94 cases (122 eyes) with ocular blast injuries. The ages of the casualties ranged between 16 and 50 years (mean age = 24 years). Sixty-five per cent of the cases were under 25 years of age.
The right eye was involved in 36 cases (38%), the left eye in 30 (32%), and binocular involvement was seen in 28 cases (30%). There was no statistically significant difference in laterality.
Ninety eyes (74%) were blind (Table 1). Six cases (6%) had bilateral blindness. The bilateral blindness rate among the binocularly injured cases was 22%.
Injuries of the iris, conjunctival and corneal foreign bodies, and corneal and/or scleral perforations were the most frequent types of injuries seen (Table 2). Of the 67 iris injuries, 27 were tears, holes, atrophies or incarcerations, 34 were cases of synechiae and iridoplegias, and six were foreign bodies. Of the 50 corneal and/or scleral perforations, 30 were corneal, 10 scleral and 10 corneoscleral.
Table 1. Visual outcome of traumatised eyes
|6/18 or better||19||15.6|
|<6/18 to 6/60||10||8.2|
|<6/60 to 3/60||3||2.5|
|<3/60 to finger counting in front of the eye||12||9.8|
|Light perception and hand movements||35||28.7|
|No light perception||21||17.2|
Table 2. Types of ocular blast injuries
|Injuries seen||No. of eyes|
|Conjunctival and/or corneal foreign bodies||63|
|Corneal and/or scleral tears (lacerations)||50|
|Cataract – Dislocated||4|
|Cataract – Ruptured||4|
|Cataract – Foreign bodies in the lens||3|
|Conjunctival tears and/or sub-conjunctival bleeding||9|
|Intraocular foreign bodies||7|
|Flat anterior chamber||6|
|Retinal detachment or optic atrophy||3|
Ocular blast injuries are among the important causes of blindness in warfare. About 74% of the eyes in this study were blind as a result of these injuries. The bilateral blindness rate in the binocularly injured cases is quite high when compared with the 11% rate in Quere’s report7of injuries during the Algerian war. It is not helpful to compare the visual outcomes because Quere’s work included a follow up period that lasted for years. The patients in our series were hospitalised for a few weeks and there was no means of follow up once they were discharged. Hence, the supposedly ‘good’ eyes could become blind and the ones with poor vision could acquire useful vision after some time. The full effect of ocular blast injuries may not be known for years. 7, 9The number of cases with hyphaema, conjunctival tears (lacerations), sub-conjunctival haemorrhages and endophthalmitis might be more than that reported here. Hyphaemas and subconjunctival haemorrhages could have been absorbed, and small conjunctival tears could have sealed by the time the patients were admitted to Menelik II Hospital. Conjunctival tears are said to occur more commonly in civilian than in military practice.11Concussion from the blast causes cataract by rupturing the lens capsule allowing access of the fibres to the aqueous humour. It may also cause dislocation of the lens, the direction of which depends on the direction of blow and the manner in which the zonules are torn.10During evaluation of the cases, care must be taken not to underestimate apparently quiet eyes with normal visual acuity.
As an example, one patient who was said to have been exposed to the smoke of a blast was referred 6 weeks after the incident. Visual acuity was 6/12 and 6/9 in his right eye and left eye respectively. The IOPs were normal. Except for a central haze in the right cornea, there was no other positive finding. The left eye was said to be ‘quiet’, although the patient experienced discomfort in his left eye. Re-evaluation a few days later showed V/A of only light perception in the left eye. The eye was hypotonic, the pupil was non-reactive to light, there was marked vitreous reaction and a total retinal detachment. X-ray revealed a foreign body in the posterior aspect of the left orbit. Hence, all cases of ocular blast injuries, however minor they may appear, are better considered serious, requiring thorough evaluation.
The author is grateful to Drs Q Pawlos and Fekede Mengistu for their kind cooperation. He would also like to thank W/t Tigest Bekele for typing the manuscript.
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9 Duke Elder S. Concussions and contusions. In System of Ophthalmology Vol.14 . London: H Kimpton, 1972:79.
10 Rones B, Wilder HC. Non-perforating ocular injuries in soldiers. Am J Ophthalmol 1947; 30: 1143-60.
11 Stallard HB. Eye Surgery, Chap. 11. John Wright & Sons Ltd, Bristol. 1965: 793.
12 WHO. Methods of assessment of avoidable blindness. WHO Offset Publication No.54 Geneva. WHO, 1980.
Management of Eye Injuries
Articles on management of eye injuries and health promotion and education for their prevention will be published in the next issue of Community Eye Health, No.24 – Editor.