Ocular Injuries in Patients with Old Blowout Fractures Following Blunt Trauma

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Abstract

Materials and Methods

Study participants

From July 2018 to June 2023, a retrospective analysis was conducted on the medical records of 1,315 adults aged 19 years and older who presented with ocular trauma to the emergency department at Gachon University Gil Medical Center (Incheon, Korea). Among these patients, 927 patients who underwent orbital or facial computed tomography (CT) scans and examined by ophthalmologists were included. We excluded patients based on the following criteria: (1) orbital trauma caused by sharp objects; (2) acute orbital or facial fractures; and (3) those with old blowout fractures who had surgical treatment. Due to these exclusion criteria, a total of 359 individuals were excluded, leaving 568 patients with 581 affected eyes for the final analysis (Fig. 1). Then, the patients were divided into two groups based on the presence of old blowout fractures: 134 (140 eyes) with blowout fractures and 434 (441 eyes) without.

Fig. 1

Study flowchart. ED = emergency department; CT = computed tomography.

Assessment of ocular trauma and complications

The study investigated demographic variables (sex and age), causes of blunt orbital trauma, and significant ocular complications in each group. The presence of old and new orbital fractures was assessed by a radiologist and two experienced ophthalmologists who reviewed the CT scans independently. In cases where there was ambiguity, the final diagnosis was reached through a consensus decision. An old blowout fracture was defined as a previous fracture of the orbital medial or inferior wall that had not been surgically treated, identified on CT scans by smoothening of the orbital contour or joining of bony edges (Fig. 2A–2D) [11–14]. The significant ocular complications included hypotony, elevated intraocular pressure (IOP), gross hyphema, dislocation of the lens or intraocular lens, vitreous hemorrhage, retinal hemorrhage, retinal detachment, retinal tear, globe rupture, and traumatic optic neuropathy. The diagnosis of ocular injuries was based on initial visual acuity, IOP measured by Goldmann applanation tonometry, slit-lamp examination, fundoscopy, and ophthalmic ultrasonography. Hypotony was defined as IOP ≤6 mmHg, and elevated IOP as >21 mmHg, with a difference >3 mmHg between the injured and uninjured eyes. Gross hyphema was defined as visible blood in the anterior chamber of the eye (grade I or higher). Lens or intraocular lens dislocation was diagnosed if there was evidence of abnormal position or phacodonesis on slit-lamp examination. Traumatic vitreous or retinal hemorrhage was diagnosed in the presence of significant posterior segment hemorrhage, excluding cases suspected to be due to underlying conditions such as diabetes or hypertension. Globe rupture was defined by full-thickness scleral or corneal laceration. Traumatic optic neuropathy was diagnosed based on visual acuity, visual field, color vision deficits, afferent pupillary defect, and findings on fundus examination.

Fig. 2

Computed tomography images showing bony contour, which is smoothening of bony contour in left medial wall blowout fracture from (A) coronal and (B) axial view; joining of bony edges in a right orbital floor blowout fracture from (C) coronal and (D) sagittal view. The arrows represent the changes in bony contour.

Results

Among the 568 patients, 392 (69.0%) were male, and the mean age of the patients was 50.7 ± 19.1 years. Among these patients, 277 had damage to the right eye, 278 had damage to the left eye, and 13 had damage to both eyes.

Out of 581 eyes from 568 patients, old blowout fractures were identified in 140 eyes (24.1%) from 134 patients, with a mean age of 56.7 ± 16.3 years. Among the 134 patients, 108 (80.6%) were from male patients. In contrast, the group without old blowout fractures included 441 eyes (75.9%) from 434 patients, with a mean age of 48.6 ± 19.6 years, of which 284 (65.4%) were male. Both the mean age and the proportion of male patients were significantly higher in the group with old blowout fractures compared to the group without (p < 0.001 and p = 0.001, respectively) (Table 1).

Table 1

Comparison of characteristics of patients between the groups with and without old blowout fractures

Severe ocular complications were observed in 93 eyes, accounting for a total of 114 incidents (16% of all eyes). The incidence of complications was significantly higher in the group without prior orbital fractures compared to the group with old blowout fractures (20.4% vs. 2.1%, p < 0.001). The most common complications were gross hyphema (4.5%), globe rupture (3.4%), and traumatic optic neuropathy (3.1%). The incidence of all of which was significantly lower in the group with old blowout fractures compared to the group without old fractures (gross hyphema, p = 0.001; globe rupture, p = 0.006; vitreous hemorrhage, p = 0.027). Other complications, such as traumatic optic neuropathy, lens or intraocular lens dislocation, retinal hemorrhage, retinal tear, high IOP, hypotony, and retinal detachment did not show significant differences between the two groups (Table 2).

Table 2

Frequency of significant ocular complications between the groups with and without old blowout fractures (n = 581)

In the multivariable logistic regression analysis, the presence of old blowout fractures was associated with a significantly lower incidence of ocular complications, with an odds ratio of 0.06 (95% confidence interval, 0.02–0.19; p < 0.001).

Among the causes of blunt eye trauma, assault was the most common (34.8%), followed by falls (24.1%) and traffic accidents (15.3%). The proportion of sports injuries, slip, and injuries from flying objects was significantly higher in the group with intraocular complications compared to the group without complications (sports injury, p = 0.025; slip, p = 0.012; flying object, p < 0.001). Conversely, assault was significantly more common in the group without complication (p < 0.001) (Table 3).

Table 3

Comparison of causes of injuries between intraocular complications group and no complication group (n = 581)

Discussion

In this study, we investigated the effect of old blowout fractures on the occurrence of ocular injuries following new blunt trauma. The major finding was that patients with old blowout fractures had a significantly lower risk of ocular complications compared to those without old blowout fractures. In addition, the causes of trauma were different between two groups with and without intraocular complications. This suggests that previous orbital fractures may provide a protective effect against subsequent trauma, possibly by altering the biomechanics of the orbital structure.

In our study, orbital blunt trauma was more likely to occur in men (69%) than in women, which is consistent with other previous epidemiology studies [3–6,15,16]. There were differences in age and sex between the groups with and without old blowout fractures in our study. This could be explained by the fact that older people are more likely to be exposed to repetitive orbital trauma, and the incidence of orbital wall fractures was higher in men than in women, as reported in previous studies [17].

The present study showed that ocular injuries were significantly less frequent in patients with old blowout fractures compared with patients without blowout fractures after blunt orbital trauma. The presence of old blowout fractures was significantly associated with lower risk of any complications. Our study is in line with previous studies. Noh et al. [4] suggest that orbital fracture may play a protective role against ocular injury by providing a decompressive effect on the orbital tissues. Several studies have also suggested that orbital fracture during blunt ocular trauma has a protective effect [5,15,16,18]. However, most previous studies focused on the association between new-onset orbital fractures and complications. There has been a lack of studies investigating whether preexisting old blowout fractures provide protection when new trauma occurs. Therefore, we suggest that not only new-onset orbital fractures, as studied in previous studies, but also preexisting old blowout fractures may offer protective effect during subsequent trauma events.

The protective effect of old blowout fractures can be explained by the crumple zone effect. This concept, introduced by Barenyi [19], engineer of the Mercedes-Benz W111 in the 1950s for car safety, refers to areas designed to deform and absorb kinetic energy during impact. A similar idea was proposed by Le Fort in 1901 for facial trauma, suggesting that sinus structures absorb impact forces to protect surrounding tissues [20]. Kellman and Schmidt [21] further supported this through cadaver studies, showing that sinuses help disperse energy in orbital fractures, reducing the likelihood of globe rupture. Our study suggests that preexisting old blowout fractures may provide a crumple zone effect. When subsequent trauma recurs, after the initial impact from trauma, the eyeball encounters a second impact against the bony structures, followed by a third within the globe. The presence of a bony defect and reactive fibrous callus tissue formed from old blowout fracture might extend the work distance and reduce peak force, offering protection during this process. However, this protective effect might not be seen in patients with old blowout fractures who undergo surgery using nondeformable orbital implants. We did not compare complication risks between patients with old blowout fractures who had surgery and those who did not. Further research is needed.

Our study revealed that the incidence of gross hyphema, globe rupture, and vitreous hemorrhage was significantly lower in the group with old blowout fractures compared to the group without such fractures. This difference may be attributed to the protective effect of orbital remodeling, which potentially functions as a crumple zone by mitigating peak forces during trauma. In contrast, complications such as retinal detachment and elevated IOP showed no significant differences between the groups. These outcomes are likely influenced by multifactorial mechanisms, including anatomical vulnerability and systemic conditions, rather than the reduction in peak force. Further research is required to elucidate the specific mechanisms underlying these findings.

In our study, the causes of trauma in ocular injuries with complication were significantly differed from those in ocular injuries without complications. The group with orbital complication was more frequently associated with flying objects, slips, or sports-related blunt eye injuries, and less commonly linked to traffic accidents and falls compared to the group without any complication. This is in line with previous study, even minor impacts might cause significant damage to a small-mass object like the eye [18]. These findings imply that the mechanism of impact transmission is a crucial factor in the occurrence of traumatic complications affecting the eyeball.

This study has several limitations. First, this study only included patients without new-onset blowout fractures. While we classified old and new fractures using CT scans, we found it challenging to differentiate between cases where a new fracture occurred on top of a previous one and cases of entirely new-onset. As a result, we chose not to include acute blowout fracture cases where identifying the very first occurrence of the fracture was difficult. Further research is needed to elucidate this. Second, our study found that the proportion of men with a history of old blowout fractures was significantly higher than in women, and these patients were significantly older than those without such injury. These differences in the patient group can be explained by the experience of at least two or more ocular traumas in patients with present injury and a history of orbital fracture. Additionally, among the complications that can arise following ocular trauma, some are influenced by cumulative effects. Patients with a history of orbital fractures may be more vulnerable to these types of complications. However, this aspect was not investigated in this study. Furthermore, the time elapsed between the trauma and the initial ophthalmologic examination, along with the variable follow-up periods, may have introduced bias in assessing the incidence of ocular injuries.

Despite these limitations, this study provides a theoretical foundation for the protective role of blowout fractures and suggests practical approaches for managing patients who experience repeated orbital trauma.

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