Ophthalmologic Injuries Associated with Maxillofacial Trauma: A Retrospective 13 Year Analysis with Trauma: A Retrospective

injury repair secondary to repair of maxillofacial The incidence of visual and maxillofacial fractures 10.8% Abstract Objective: A study was designed to evaluate the incidence, mechanism of injury and treatment outcomes of ophthalmic injuries associated with maxillofacial trauma. Material and Methods: 3708 patients who sustained maxillofacial trauma during the years from August 2006 to July 2019 and were included in this retrospective study. Patients’ records were reviewed for gender, age, site of injury, aetiology of trauma, concomitant injuries, ophthalmic assessment and method of treatment. Minor and major ophthalmic injuries were recorded. Results: Of the 103 patients, 81 were male with a median age of 38 years. Road traffic accident was the most common mechanism of injury (72/103, 70%). Common minor ophthalmic injuries included diplopia, enophthalmos, subconjunctival haemorrhage and restriction of the extraocular muscles, while major injuries included subretinal haemorrhage, retrobulbar haemorrhage, ruptured globe and detached retina. Most major ophthalmic injuries occurred in association with orbital fractures. Visual acuity was reduced in 15 patients, four of whom experienced persistent postoperative changes at eight weeks. Lack of vehicle drivability showed a highly significant association with major ophthalmic injury (p=0.001). The incidence of loss of vision was 0.97% (1/103). Conclusion: Prompt assessment and treatment of ophthalmic injuries is of paramount importance in patients with fractures involving fractures of orbital walls.


Introduction
Ocular injuries very often are associated with maxillofacial trauma. Injuries to and around the eye may vary in presentation and severity. Careful ophthalmic examination must be a part of the initial assessment in all maxillofacial trauma patients [1]. Blindness is a potential complication from missed ophthalmic injuries, while certain ophthalmic injuries may be readily evident. In case such injuries are missed at first observation, the treating surgeon may face medicolegal consequences [2]. Opthalmic injuries may range from certain minor ophthalmic injuries such as abrasions or lacerations to the eyelids or cornea to major injuries which may be potentially blinding. In all motor vehicular accidents, the injury tends to be severe, leading to fracture of the orbit or rupture/ penetration of the globe by glass pieces [1].
An ophthalmologist must be a part of the treating team for ocular injury assessment and management. Maxillofacial surgeons may not be aware of many types of ocular injuries that may occur as well as their diagnosis, appropriate therapy or ultimate prognosis. Some ocular injuries may mandate concomitant surgical treatment with maxillofacial fracture repair, while in some cases, presence of an ocular injury may mandate a delay in ophthalmic injury repair secondary to repair of maxillofacial fractures [3]. The incidence of visual loss and blindness from maxillofacial fractures varies from 0.7 to 10.8% [4] and the causes reported in literature include retrobulbar haemorrhage, ruptured globe and traumatic optic neuropathy. Preoperative assessment of ophthalmic injuries is providing a safeguard to the maxillofacial surgeon. Ophthalmic injury management must be given preference over facial fracture repair, as surgical treatment of the facial fractures in the presence of an untreated severe ophthalmic injury may exert pressure on the eye. This may eventually hamper the prognosis for the globe [5].
Recognition of an ophthalmic injury before operative intervention is important as it guards against a postoperative allegation from the patient alleging the surgical procedure to be the cause of any permanent visual disturbance.
The objective of this study was to determine the incidence and types of ocular and motility disorders in patients who had sustained maxillofacial injuries. Further, we aimed to evaluate mechanism of injury, facial fracture type and treatment outcomes of patients treated for ophthalmic injuries and maxillofacial bone fractures. Patients' personal and clinical data, mechanism of injury and clinical ophthalmic signs were reviewed. All patients had signed informed consent letters as part of the presurgical protocol.

Methods
Ophthalmic signs were divided into "minor" or "major" based on the chances of the injury leading to permanent loss of vision. Impairment of visual acuity was categorized as "mild" with readings of 6/12 or 20/40, "moderate" between 6/12 or 20/40 and 6/60 or 20/200 or "severe" with less than 6/60 or 20/200, following a careful assessment. Patients were grouped into four groups depending on the type of operative intervention that they Drivability criteria involved a measurement of visual acuity for each eye separately and without optical correction. In cases where optical correction was needed, vision was retested with appropriate corrective lenses. A standard visual acuity chart such as Snellen chart was used with five letters on the 6/12 line. Charts are placed six metres from the person tested. More than two errors in reading the letters of any line were regarded as a failure to read that line. In the case of a private vehicle driver, uncorrected vision (without eye glasses) must be a minimum of 6/12 to pass the drivability criteria.
For commercial vehicle drivers, visual acuity in the driver's both eyes or better eye (with or without corrective lenses) must be 6/9 or better. 6/9 or 6/12 vision meant that the patient must be able to Lilliefors significance correction was used to test for normality of continuous variables in the study. Based on the outcome of the normality test, median and inter quartile range (IQR) for nonparametric data were derived. Descriptive data were reported as a number (%). Categorical data were analysed using the Chi square test to determine whether there was a significant difference between minor and major ophthalmic signs and other variables.
Binary logistic regression was utilized to assess the significance of association between minor and major ophthalmic signs, the severity of visual impairment, and its association with the various locations of fractures. A probability value of < 0.05 was considered as statistically significant.
Minor and major ophthalmic findings are outlined in Tables 1 & 2.

Discussion
This study retrospectively analysed data on patients' personal and clinical details, mechanisms of injury and the preoperative ophthalmological injuries associated with maxillofacial fractures.

Studies have indicated the association between ophthalmic injuries
and midface fractures [6,7]. However, these studies failed to specify the type of fracture or the specific ophthalmic injuries sustained.

Most of these studies have reported ocular injuries in patients with
midface fractures in general [8], without specific categorization of maxillofacial fractures. However, our study has segregated ophthalmological injuries into those associated with the four different categories of fractures. The results indicated that there were considerably more male than female patients (81/103, 79%) with maxillofacial fractures and the median age was 38 years (IQR 18-59). These findings were consistent with the results of some previous studies [6,7]. The distribution of mechanism of injury was predominated by road traffic accidents, followed by a distant second by interpersonal violence or assault. This pattern is drastically different from similar studies on ocular injuries [5,9,10], where the predominant cause of injury was alcohol-related assault. This difference could be attributed to the fact that all these studies were carried out western countries where there is a higher prevalence of alcohol-related interpersonal violence.
The reported incidence of ophthalmic injuries associated with maxillofacial fractures is very much dependent on the exact classification system used to quantify them. This study has segregated ophthalmic injuries into minor/temporary/ reversible injuries and major/irreversible/permanent injuries.
This classification was modified from those described previously [11,12]. This study confirms the fact that the reported incidence of major ophthalmic injuries is low [13,14]. A majority of the major ophthalmic injuries were recorded in group 2 and 3. This finding seems to suggest that a greater degree of intraocular damage can result from these types of fractures than by any other maxillofacial fractures.
The univariate logistic regression analysis for ophthalmic injuries and types of fracture showed no statistically significant relation. However, findings from the study indicated that, fortunately, minor ophthalmic injuries are more likely than major ophthalmic injuries. Two patients experienced retrobulbar haemorrhage, one had traumatic optic neuropathy and one had a ruptured globe.
Traumatic optic neuropathy can be a cause of severe permanent visual impairment, many times with concomitantly reduced visual acuity or a relative afferent papillary defect [15]. However, the patient in our study regained full vision following high dose steroid therapy with concomitant reduction of fractures and fixation.

Permanent loss of vision or blindness is an unfortunate
complication associated with maxillofacial fractures, whose reported incidence varies between studies, 0.32%-9% [16] and 0.7-3% [7]. This devastating consequence may manifest as a result of direct injury to the globe, optic nerve injury, retinal oedema or detachment, vascular compromise to the eye, intracranial injury to the optic chiasm or brain and retrobulbar hemorrhage [16,17]. It would be prudent to think that patients on anticoagulants might be at an increased risk of a retrobulbar bleed. Therefore, a careful medical history must be sought at initial examination. Furthermore, literature review indicates that blindness is commonly observed with penetrating injury to the globe, an increased number of facial fractures, ZMC complex fracture, a Glasgow Coma Scale score less than or equal to 8 at examination and involvement of all three eye zones from injury [18]. Some uncommon causes of blindness reported in literature include optic nerve transaction, globe luxation and retinal detachment [19]. Out of the two patients with retrobulbar haemorrhage in this study, one lost vision in the eye.
Reduced visual acuity was diagnosed in all patients who did not score 6/6 on visual assessment. Five patients with major ophthalmic injuries (5/14, 36%) and 10 out of 85 patients (10/85, 12%) with minor ophthalmic injuries experienced reduced visual acuity in our study. Twelve of these 15 patients needed orbital wall reconstruction. Similar percentage distributions were reported by other studies [11,20]. This finding reinforces the fact that greater intraocular damage may be expected from maxillofacial fractures that disrupt orbital walls than after other types of fracture.
Four patients experienced persistent postoperative changes at 12 weeks, with preoperative ophthalmic injuries of commotio retinae, subretinal haemorrhage, globe rupture and retrobulbar haemorrhage.
Drivability relates to the patient's ability to drive independently, whether private (lesser than 6/12) or commercial vehicles (lesser than 6/9). There was a significant association of male gender with ocular injuries, a finding derived from the fact that maxillofacial fractures were also predominant in the male population in our study.
Visual acuity and papillary reactivity did not differ significantly.
However, the study found an OR of 0.07 (95% CI 0.03 to 0.20, p = 0.001) for those patients who had a major ophthalmological sign and inability to drive, which was statistically significant.
No significant associations were observed in univariate logistic regression analysis between impairment of visual acuity and types of fracture. However, findings from the study reinforce the finding that visual impairment is a risk of any maxillofacial fracture that involves the orbit. Improvement in visual acuity within a week of the injury has been reported [20], a finding confirmed in our study.
Fractures of the Le Fort III level and ZMC fractures, even when present as a part of panfacial fractures are associated with a higher proportion of major than minor ophthalmic injuries. This fact may be a result of high velocity being the main mechanism of trauma in such cases [4]. Similar observations have been reported in other studies on the subject [16,21,22].
The retrospective design of the study was a shortcoming

Conclusion
Ophthalmic injuries must be suspected in midface injuries and promptly evaluated by an ophthalmologist, particularly in case of ZMC and Le Fort II/ III fractures. Minor injuries are commoner than major injuries. However, a missed diagnosis of ophthalmic injury could lead to permanent alteration or loss of vision, thereby inviting medico legal consequences.