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| Journal of the New Zealand Medical Association,
20-January-2012, Vol 125 No 1348
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Ocular trauma epidemiology: 10-year retrospective
study
Archana Pandita, Michael Merriman
Ocular trauma is a major public health issue. Ocular trauma
mostly commonly occurs at work, at home, during sport activities, motor vehicle
crashes or interpersonal trauma. Reported risk factors are male gender,
workplace, road accidents, alcoholism and lower socioeconomic
class.1–3 It is a significant but
preventable cause of blindness worldwide.
Ocular trauma has an impact on the healthcare system and
also the wider economy due to time off work. Negrel and Thylefors reported that
worldwide 1.6 million people are blind secondary to ocular injuries, 2.3 million
with low visual acuity bilaterally and 19 million with unilateral blindness or
low vision.4
Around 29,000 eye injuries occur in Australia
annually.1 Hospital admissions are not a
complete record of prevalence and risk factors for ocular trauma because mild to
moderate injuries such as corneal foreign bodies and corneal abrasions are not
included as they are treated as an out patient. However nearly all severe and
blinding injuries can be captured by using hospital admission data. Not only is
the trauma often preventable but appropriate management of injuries can have a
significant reduction on the burden of the visual impairment.
Waikato is the fourth largest region in New Zealand and has
a population of just over 400,000. It includes Hamilton, a large urban centre
(41% of population), but mainly comprises rural areas and small towns (59% of
population). The purpose of this retrospective study is to determine the
incidence and risk factors associated with ocular trauma in Waikato.
Waikato Hospital provides secondary and tertiary care to the
region and serves as a major referral centre for a geographical area of 25,000
km2. The department of Ophthalmology at Waikato
Hospital offers both emergency and specialised care for ocular diseases and
conditions for patients of all age groups.
A better understanding of the risk factors associated with
it can help to design targeted campaigns to reduce the incidence of ocular
trauma in community and develop effective plans for disseminating eye injury
prevention material to the public.
MethodsFor this study case notes were reviewed with ocular
trauma who presented to Waikato Hospital from January1999 to December 2008.
Patient records were identified by computer search using Waikato
Hospital’s RUS codes (Resource Utilization System, equivalent to ICD
codes) for all patients admitted.
Ocular injury was defined as any injury affecting eye
or adnexa identified as principal discharge diagnosis. RUS codes for ocular
trauma included contusion, penetrating wounds of orbit with and without foreign
body, perforation, rupture, ocular laceration with and without prolapse or loss
of intraocular tissue, injury of conjunctiva and corneal abrasion.
Patient data extracted included age, sex, ethnicity,
type of trauma (sharp/blunt), location and nature of trauma, chemical injuries
and burns. Visual acuity at the time of presentation and discharge was recorded
using the Snellen’s visual acuity chart. Details of slit lamp examination
including fundus examination were noted.
Any computed tomography and ultrasound findings were
recorded. Primary and secondary repair including adjuvant treatment was noted.
Medical and surgical history was recorded. Any alcohol consumption at the time
of trauma was noted. Injuries were classified by the standardized international
classification of ocular trauma, Birmingham Eye Trauma Terminology system
(BETTS).5
Statistical analysis was performed in conjunction with
a professional biomedical statistician. Frequency distributions were created for
injury type and cause. The eye injury rate was calculated using denominator
obtained from NZ institute of statistics. Statistical analysis of quantitative
data was performed for all variables. Frequency analysis was performed by the
Chi-squared test. One way analysis of variance (ANOVA) was used to evaluate
difference in parametric variables. Chi-squared test or Fischer exact test was
used as appropriate. All p values were two tailed and p-value less than 0.05 was
considered statistically significant.
ResultsThere were total of 821 patients who were admitted to
Waikato Hospital with ocular injuries between January 1999 and December 2008.
Among these 52 % were New Zealand European, 35% were Maori and 13% were from
other ethnicity (mainly Asian, Pacific, or Middle East). NZ Europeans are 80% of
total Waikato population and Maori are the 15% of population.
Adjusting for age and gender, men had higher rate of ocular
trauma than women (74% vs 26%, p<0.001, Pearson’s Chi-squared test).
The mean age for all patients in this study was 35.5 years (range 0–98
years). Mean age for males was 31.0 (±20.8) and for females was 37.0
(±24.7; p=0.005 ANOVA test). Median age was 42 years. No significant
difference in frequency of right vs left eye injuries was noted (p=0.522).
Figure 1. Eye trauma incidence in various age
groups over 10 years period
 Table 1. Activity when eye injury
occurred
DIY=do it yourself work.
The incidence of eye injury was seen to be decreasing with
increasing age. The maximum number of injuries was seen in the age group 16-20
years and 26-30 years (11.5% and 11.3% respectively, Fig 1). 21.5% of the New
Zealand population is less than 15 years and 12.3% is above 65 years age. The
younger age group had assault and metal work as a main cause of ocular injuries.
Elderly people had ocular injuries mainly from falls. Using
the Birmingham Eye Trauma Terminology System (BETTS), contusion affecting the
anterior segment occurred most frequently among different forms of ocular trauma
(Table 2).
Figure 2. Frequency of injury by gender and
activity
 There was a correlation between activity when injured and
gender (p<0.001; Pearson Chi-squared test) (Figure 2). Outdoor activity
related injuries accounted for 34.8% of injuries in men followed by work related
injuries (29%). The most frequent cause of ocular trauma in women was outdoor
activity related (43%) followed by home related work (20%). Assaults accounted
for 9.2% of all injuries and among these alcohol use was documented in
73.6%.
Table 2. Type of eye injury
BETTS=Birmingham Eye Trauma Terminology System.
There were 253 open globe injuries and 568 closed globe
injuries (p<0.001; Pearson’s Chi-squared test). There was a significant
difference in the frequency of open and closed globe injuries in work related
injuries (58% open vs 42% closed, p=0.044 ; Fisher's exact test), sports-related
injuries (23% open vs 77% closed, p<0.005;Fisher's exact test), outdoor
related activities (17% open vs 83% closed, p<0.005; Fisher's exact test) and
in MVA-related injuries (28% open vs 72% closed, p=0.001; Fisher's exact test)
respectively (Figure 3).
Figure 3. Frequency of injury by open
globe/closed globe
 A vitreoretinal procedure was performed in 54 eyes and three
among these had repeat vitrectomy to improve vision. Nineteen eyes had
vitrectomy for intraocular foreign bodies, 15 metal and 4 glass. Seventeen eyes
had vitreoretinal procedures for retinal detachment repair. Another 17 eyes had
reasons such as retinal haemorrhages, lens dislocation, decreased visual acuity
after primary repair. One had vitrectomy for dislocated intraocular lens after
blunt trauma.
There were 82 ocular injuries presenting to Waikato Hospital
on average per year with an incidence rate of 20.5 (CI 19.3–21.5) per
100000 population (Fig 4). Incidence rate for CGI was 14.2/100,000 and for OGI
was 6.3/100,000 population. Overall 590 eyes had BCVA( Best corrected visual
activity)≥ 6/12 (71.8%), 143 had VA between 6/12 (17.4%) and 6/60 and 88
eyes had VA≤ 6/60 (10.7%) at final follow-up visits.
Generally it was seen that eyes injured with blunt objects
had final BCVA of 6/12 or better compared to those injured by sharp objects. The
majority of chemical injuries (82%) happened at work with sodium hydroxide and
sodium hypochlorite being the dominant agents. Chemical injuries occurring at
home (18%) were usually due to cleaning agents. All the chemical and firework
injuries had full recovery of VA except one firework injury in a corneal graft
patient whose VA was reduced from 6/9 to hand movements.
Figure 4. Incidence of ocular injuries per
year
 Table 3. Source of trauma for Visual acuity
less than or equal to 6/60
The most common primary surgery was reconstitution of the
globe integrity with repositioning or excision of extruded ocular contents and
suturing of the wound. There were a total of 27 (3.2%) enucleations performed
during this period that included 12(44.4%) primary and 15(55.6%) secondary
enucleations.
Six (0.7%) eviscerations were performed, three for
penetrating eye injuries, one for endophthalmitis resulting from IOFB
(intraocular foreign body) and one each for complications from motor vehicle
accident and scleral rupture.
Of the 19 cases of IOFB three developed endophthalmitis (two
metallic and one organic).Two had bacillus species identified, the other had
negative cultures. Two of these were treated with intravitreal antibiotics and
vitreoretinal procedures and third one underwent evisceration.
Four eyes (0.5%) developed pthisis. No case of sympathetic
ophthalmia (inflammation to both eyes following trauma to one eye) was seen in
this study. Angle recession was noted in 1.5% (n=13) eyes.
DiscussionOcular trauma is an important cause of visual loss and is
frequently preventable. This study documents the nature of the ocular trauma
over a 10-year period. We must acknowledge that only inpatients are included.
However most patients with sight-threatening injuries are admitted.
Some closed globe injuries are treated as outpatients and
will not be included in this study (e.g. Commotio retinae). Data was collected
based on discharge coding, so some injuries would have been left out for example
multisystem trauma with relatively mild eye injuries. As a retrospective study
there will be recording bias. The vision at presentation and final follow-up was
not recorded for every injury. Not all patients had complete treatment at
Waikato Hospital so their final outcome may not be known.
Estimation of ocular trauma rates depends on the data
source. Hospital data does not represent the total number of patients with eye
trauma as not all the less severe injuries will present to hospital, but it will
provide useful information regarding sight-threatening injuries which are of
greatest concern.
This study provides insight into epidemiology of ocular
trauma in New Zealand. It also supports the previous reports that ocular trauma
may represent a significant cause of visual loss in the population.
The rates of eye injuries requiring hospital admission range
from 8-57/100,000 population.1,6-10 This study
showed an incidence rate of 20.5/100,000 which is more than other reports from
United States but comparable to Australia
(21/100,000).1This could be related to factors
such as increased outdoor activities in this region and comparatively easier
access to public health system.
As a large geographic area, Waikato has an extensive road
network that could contribute to a greater number of road traffic accidents
compared to other regions. Some of our patients identified and included were
from outside our region but treated at Waikato Hospital due to their location at
time of injury e.g. MVA, or transferred to our centre for specialised treatment
(e.g. vitreoretinal surgery).
Higher frequency of ocular injury in men was seen in our
study population and occurred in all age groups. A higher male preponderance may
be related to occupational exposure, participation in dangerous sports and
hobbies, alcohol use and risk taking
behaviour.11 Other studies also reported higher
rate in men compared to women.1,3,15
This study showed that sports and motor vehicle accidents
contribute to about 15% of ocular injuries. Rugby was found to the commonest
cause of sports injury followed by tennis and squash. Other less common sports
eye injuries were from fishing, soccer, boating, golf, shooting and paint ball.
Work-related equipment was found to be the other major
contributory risk factor for ocular injuries. Among these, lawn mowing caused
highest eye injuries and others included fencing, hammering, tree pruning and
grinding.
Excess alcohol consumption was identified as a contributing
factor in approx 13.8% of injuries in our cohort, predominantly in assault and
MVA activities. Of the 88 eyes with severe visual loss, assault and MVA caused
36%. Three quarters of eye injuries due to assault involved alcohol
consumption.
Closed globe injuries have better prognosis compared to open
globe injuries.12 Pieramici et al described
that good presenting visual acuity of 6/60 or better is associated with less
incidence of enucleation.13 This is consistent
with other studies and is an important prognostic factor when counselling these
patients. However vitreoretinal procedures in eyes with vision of hand movements
resulted in measurable vision improvement in subsequent follow-up in some of our
patients.
This study detected three cases of post traumatic
endophthalmitis. This was 1.1% of the open globe injuries. No post operative
endophthalmitis was seen. Post-traumatic endophthalmitis is reported in
2–12% of eyes with open globe injuries in other
studies.14-19
Risk factors include delayed presentation, delayed
commencement of antibiotics and presence of intraocular foreign body. This study
has a comparatively low rate of endophthalmitis which is probably a consequence
of prompt presentation, early antibiotic treatment and surgery.
There was a single gunshot perforating wound in the ten
years of our study. This eye had pars plana vitrectomy, lensectomy and laser
vision improved to 6/5 BCVA.
Ocular trauma is a significant cause of visual disability.
Typically it impacts younger people and may dramatically affect their future,
independence and work. Health education and appropriate preventive measures
should therefore be directed at these high risks.
Our study shows that educating workplaces and people doing
high risk tasks such as drilling, grinding, chain sawing and farm fencing would
be a good target to reduce ocular injuries. Adequate eye protection is often a
simple step. Education of the community regarding the high association of
alcohol and eye injuries leading to blindness from MVA and assaults could be a
useful in changing society’s attitude to alcohol use.
Competing interests: None
declared.
Author information: Archana Pandita,
Registrar; Michael Merriman, Consultant; Department of Ophthalmology, Waikato
Hospital, Hamilton
Correspondence: Archana Pandita, 26
Kentwood Drive, Wellington 6037, New Zealand. Email: panditaarchana@yahoo.com
References:
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