Optic neuropathy following simulation of orbital hemorrhage in the nonhuman primate

Bilateral Orbital Compartment Syndrome Following a Craniotomy With Coronal Incision

BACKGROUND

Orbital compartment syndrome is a rare ophthalmic emergency characterized by increased intraorbital pressure and hypoperfusion of critical neural structures, most of which were caused by trauma, and can also be caused by periorbital surgery, local injections, other preexisting medical conditions and so on. It requires rapid identification and immediate treatment for the preservation of vision.

CLINICAL PRESENTATION

A 61-year-old female with left frontal lobe-parafalcine meningioma underwent a craniotomy with a bicoronal incision. Postoperatively, the patient presented absence of pupillary reaction in both eyes, and complained loss of vision after recovery from anesthesia. Bilateral orbital compartment syndrome was considered 18 hours postoperatively since the marked bilateral proptosis with eyelid edema and conjunctival chemosis. The patient was treated with methylprednisolone, mannitol, hyperbric oxygenation, and neurotrophic agents as recommended by the ophthalmologist. There was no improvement in visual acuity at discharge or at 3-month follow-up postoperatively.

DISCUSSION AND CONCLUSION

This is a rare case of bilateral irreversible blindness caused by orbital compartment syndrome after a craniotomy with coronal incision. Neurosurgeons need to improve the awareness of this complication for adequate prevention, such as direct ocular pressure from skin flaps, congestion from head positioning, and adequate intraoperative eye protection, and also earlier recognition and management.

Imaging the Tight Orbit: Radiologic Manifestations of Orbital Compartment Syndrome

BACKGROUND AND PURPOSE

Orbital compartment syndrome is a sight-threatening emergency caused by rising pressure inside the orbit. It is usually diagnosed clinically, but imaging might help when clinical findings are inconclusive. This study aimed to systematically evaluate imaging features of orbital compartment syndrome.

MATERIALS AND METHODS

This retrospective study included patients from 2 trauma centers. Proptosis, optic nerve length, posterior globe angle, morphology of the extraocular muscles, fracture patterns, active bleeding, and superior ophthalmic vein caliber were assessed on pretreatment CT. Etiology, clinical findings, and visual outcome were obtained from patient records.

RESULTS

Twenty-nine cases of orbital compartment syndrome were included; most were secondary to traumatic hematoma. Pathologies occurred in the extraconal space in all patients, whereas intraconal abnormalities occurred in 59% (17/29), and subperiosteal hematoma in 34% (10/29). We observed proptosis (affected orbit: mean, 24.4 [SD, 3.1] mm versus contralateral: 17.7 [SD, 3.1] mm; P < .01) as well as stretching of the optic nerve (mean, 32.0 [SD, 2.5] mm versus 25.8 [SD, 3.4] mm; P < .01). The posterior globe angle was decreased (mean, 128.7° [SD, 18.9°] versus 146.9° [SD, 6.4°]; P < .01). In 69% (20/29), the superior ophthalmic was vein smaller in the affected orbit. No significant differences were detected regarding the size and shape of extraocular muscles.

CONCLUSIONS

Orbital compartment syndrome is characterized by proptosis and optic nerve stretching. In some cases, the posterior globe is deformed. Orbital compartment syndrome can be caused by an expanding pathology anywhere within the orbit with or without direct contact to the optic nerve, confirming the pathophysiologic concept of a compartment mechanism.

Orbital and Intracranial Emphysema Causing Orbital Compartment Syndrome: A Rare Case Report and Literature Review

A case of 50-year-old male who presented with orbital compartment syndrome as a sequela of mid facial trauma, and literature review. Orbital compartment syndrome (OCS) is one of the potentially sight threatening emergencies encountered in clinical practice. Acute rise in pressure within the confined orbital cavity compromises the blood flow to retina and optic nerve leading to irreparable vision loss. Air entrapped in the orbital cavity leading to orbital compartment syndrome has been rarely reported. A brief literature search for the term orbital emphysema in PubMed yielded 352 articles out of which 280 articles were identified after screening for appropriate titles and case reports. A total of 138 patients were reported in the literature with severe orbital emphysema. Acute orbital compartment syndrome needs to be recognized and addressed on an emergency basis to achieve decompression so as to prevent an irreversible vison loss. Watchful eyes, an accurate diagnosis and timely surgical intervention could potentially reverse permanent damage to the optic nerve.

Orbital Compartment Syndrome After High-speed Air-Gasoline Blast Injury

Orbital compartment syndrome is an ophthalmologic emergency that requires timely surgical intervention. The authors present a rare case of orbital compartment syndrome in a 30-year-old male injured by forceful entry of air-gasoline mixture into the orbit, secondary to inadvertent firing of the piston from running mechanical diagnostics on an automobile internal combustion engine. Orbital CT revealed extensive orbital emphysema with both pre- and postseptal involvement and diffuse chemical cellulitis. Serial exams revealed rapid deterioration of vision with elevated intraocular pressure and development of eyelid, corneal, and orbital edema; a relative afferent pupillary defect and optic nerve hypoperfusion. He was started on intravenous steroids and underwent an emergent lateral canthotomy with cantholysis, which temporarily reduced the intraocular pressure. However, a second rapid increase in soft tissue swelling resulted in another episode of ocular hypertension and compressive optic neuropathy, requiring emergent orbital bony decompression, which was followed by decreased intraocular and orbital pressure. The patient later developed progressive corneal opacification indicating delayed chemical injury. This was managed with a 10-day course of aggressive topical and systemic antiinflammatory agents with significant improvement in visual acuity. At last follow up, the vision was 20/30 and the corneal and eyelid edema had cleared.

Left orbital compartment syndrome and right anterior ischemic optic neuropathy in a patient with severe burns despite non-aggressive fluid resuscitation

INTRODUCTION

Ophthalmological complications such as orbital compartment syndrome (OCS) and ischemic optic neuropathy are rare complications in patients with burns and have been described in patients where aggressive fluid resuscitation was performed. While OCS requires urgent surgical intervention, no current treatment is established to treat, or prevent, ischemic optic neuropathy in patients with burns.

METHODS

The authors report a case of a 38-year-old woman with flame burns including the periorbital regions who developed OCS on the left side and anterior ischemic optic neuropathy (AION) on the right side despite non-aggressive fluid resuscitation. Immediate lateral canthotomy combined with inferior cantholysis was performed on the left side.

DISCUSSION AND CONCLUSION

OCS and AION need to be considered as potential complications even in critically ill patients with facial burns who do not receive aggressive fluid resuscitation. Whether an early surgical intervention will lower the risk of AION development is, however, speculative.

LAY SUMMARY

Ophthalmological complications such as orbital compartment syndrome and ischemic optic neuropathy are rare complications in patients with burns and have been described in patients where aggressive fluid resuscitation was performed. We present a case of a critically ill patient with severe facial burns who developed orbital compartment syndrome on the left side and anterior ischemic optic neuropathy on the right side even though our patient did not receive aggressive fluid resuscitation.Our case is particular because both of these rare complications are seen in a single patient and neither received aggressive fluid resuscitation. The fact that the patient did not develop ischemic optic neuropathy on the side where the lateral canthotomy was performed (only on the side where the patient had orbital compartment syndrome), this case might raise the discussion of whether an early surgical intervention might lower the risk of ischemic optic neuropathy development in patients with facial burns.

Orbital Compartment Syndrome and Irreversible Blindness Related to Orbital Varix Thrombosis: A Case Report

BACKGROUND

Orbital compartment syndrome (OCS) is an ocular emergency that can severely threaten the visual potential. The most common etiologies include facial trauma-related orbital wall fractures and postoperative bleeding within the orbit. Nontraumatic cases were also reported sporadically, although they are rare. The orbital volume limits the compliance to expand when space-occupying lesions develop. Both direct compression of the optic nerve and depleted perfusion from elevated intraorbital pressure subsequently lead to ischemic optic neuropathy and vision loss.

CASE REPORT

A 74-year-old man experienced headache, bulging left eye, dull pain, vision loss, nausea, and vomiting within 1 day. Computed tomography and magnetic resonance imaging revealed a heterogeneous mass extending from the orbital apex and connected with the ophthalmic vein. Lateral canthotomy and cantholysis were performed at bedside for emergent orbital decompression. The proptosis and pain relieved after surgery, but visual loss remained irreversible. Surgical exploration was conducted and pathology proved the diagnosis of varix of the ophthalmic vein with thrombosis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Clinicians should be aware of the presentation of OCS and perform timely orbital decompression, which could reverse visual impairment. These patients might also benefit from immediate consultants with ophthalmologists and radiologists.

Evidence-based algorithm for the management of acute traumatic retrobulbar haemorrhage

Retrobulbar haemorrhage (RBH) is a potentially blinding consequence of craniofacial trauma, but timely ophthalmic evaluation is difficult to obtain in some settings and clear standards for canthotomy/cantholysis are lacking. We have sought to develop an algorithm to identify vision-threatening traumatic RBH that requires emergent decompression. We retrospectively reviewed 42 consecutive consultations for RBH at a level-one trauma centre. Charts and imaging studies were analysed with attention to mechanism of injury, comorbid trauma, and ophthalmic findings. A total of 22 eyes were observed without intervention, 13 were treated pharmacologically, and seven by emergent canthotomy/cantholysis. No differences in standard trauma metrics were found among these groups. Lid oedema, ecchymosis, chemosis, subconjunctival haemorrhage, and ocular motility also failed to correlate with a need for surgical intervention. "Tight" eyelids (p<0.001), unilateral proptosis (p<0.001), and relative afferent pupillary defect (RAPD; p=0.029), however, all related to a need for canthotomy/cantholysis (Fisher's exact test). Tenting of the globe, which was the only radiographic finding to predict the need for surgery, was seen in just two of the seven cases that required decompression. Many of the traditionally emphasised clinical signs therefore fail to identify cases of RBH that require decompression. Our data support a simple three-factor decision tool. These are: relative proptosis, eyelids that are difficult to open with finger pressure, and presence of an RAPD in the traumatised eye. If all three are noted or if the patient has proptosis and tight lids in the absence of a large preseptal haematoma, he/she is likely to need surgical decompression. Tenting of the globe on computed tomography (CT), while a relatively rare finding, should also alert the physician of the need for intervention.

Orbital Compartment Syndrome: An Update With Review Of The Literature

Orbital compartment syndrome (OCS) is a potentially blinding condition characterized by a rapid increase in intra-orbital pressure. OCS is most commonly seen in the context of intra-orbital hemorrhage secondary to either trauma or surgery. A review of the literature indicates that better visual outcomes are achieved when interventions occur within the first 2 hrs. There are reports of visual recovery after a delay in management and consideration should be given to intervention even when presentation is delayed. Reported interventions include: lateral canthotomy with cantholysis, bony orbital decompression and treatment of the underlying cause.

Animal Models Used to Simulate Retinal Artery Occlusion: A Comprehensive Review

Purpose

To present an overview of animal models of retinal artery occlusion (RAO).

Methods

Through a systematic literature search in PubMed and Embase, papers describing methods of inducing RAO in animal models were included. The identified methodologic approaches were presented in a narrative synthesis and compared with RAO in humans.

Results

In total, 83 papers reporting on 88 experiments were included. Six different species were used with rodents and monkeys being the most common, and a minority were performed using cats, dogs, rabbits, or pigs. The anatomy of pigs and monkeys resemble that of humans most closely. The two most frequently used methods were laser-induced occlusion or ligation of the arteries. Other methods included raised intraocular pressure, arterial clamping, administration of vasoconstricting agents, the use of an occluder, embolization, and endovascular approaches to induce occlusion. In general, occlusions lasted for only 30 to 90 minutes, often followed by reperfusion.

Conclusions

Although a broad range of methods have previously been used, they all have limitations. Preferably, the methods should imitate the human disease as closely as possible and avoid damaging other structures. Therefore, monkeys followed by pigs are to be preferred and ligation or clamping may be a suitable model in larger animals as there is a potential to isolate and occlude the retinal artery only. Being less invasive, laser-induced occlusion is another suitable approach.

Translational Relevance

This review aims at assisting researchers in deciding on the most ideal experimental setting, and thereby increase the translational value to human disease.

Paracanthal "One-Snip" Decompression in a Cadaver Model of Retrobulbar Hemorrhage

PURPOSE

The authors assess the effectiveness of a modified paracanthal or "one-snip" procedure compared with the traditional lateral canthotomy and inferior cantholysis in the reduction of intraocular pressure (IOP) and proptosis in a human cadaveric model of retrobulbar hemorrhage.

METHODS

This study comprised a comparative interventional study in a cadaveric model of retrobulbar hemorrhage. Six orbits of 3 fresh cadavers were included in the study. Baseline measurements of IOP and proptosis were recorded for all 6 orbits before and after simulation of retrobulbar hemorrhage as previously described. Right orbits (n = 3) underwent traditional lateral canthotomy and inferior cantholysis. Left orbits (n = 3) underwent modified paracanthal or "one-snip" procedure. The primary outcome measures were reduction in IOP and proptosis between the 2 techniques.

RESULTS

Following lateral canthotomy and inferior cantholysis of each right orbit, the average IOP dropped to 14 mm Hg (range of 11-18 mm Hg), corresponding to a mean decrease of 32 mm Hg. Following the "one-snip" procedure of each left orbit, the average IOP dropped to 19 mm Hg with a range of 16 to 23 mm Hg, corresponding to a mean decrease of 22 mm Hg. There was no statistically significant difference in IOP reduction (p = 0.36) or proptosis reduction (p = 0.23) between the 2 treatment groups.

CONCLUSIONS

Compared with traditional lateral canthotomy xand inferior cantholysis, the modified paracanthal or "one-snip" procedure is effective for IOP reduction and led to mild improvement of proptosis in a cadaveric model of retrobulbar hemorrhage. The authors hope this study helps improve orbital compartment syndrome outcomes by providing an option that more providers will feel comfortable performing and therefore decreasing time to surgical decompression.

Extraocular Pressure Measurements to Avoid Orbital Compartment Syndrome in Aneurysm Surgery

BACKGROUND

Orbital compartment syndrome (OCS) is a rare but devastating complication following pterional craniotomy. Although the causes of OCS are unclear, external compression of the orbit by a myocutaneous flap is commonly mentioned as a major factor. We evaluated the ocular influence of external compression using an extraocular pressure monitor.

METHODS

We measured extraocular pressure in 86 patients who underwent surgery for cerebral aneurysm via a pterional approach. Clinical information and radiologic parameters, including the area of the medial rectus muscle (MRM) and the craniotomy height from the bottom of the anterior skull base, were collected. As a control group, 117 patients who underwent surgery without pressure monitoring were also evaluated.

RESULTS

Extraocular pressure reached a maximum during craniotomy (mean, 22.0 mm Hg; range, 18.4-51.0 mm Hg) and decreased after myocutaneous flap adjustment (mean, 7.9 mm Hg; range, 5.4-17.5 mm Hg). Pressure before myocutaneous flap manipulation differed between patients with anterior communicating artery (Acomm) aneurysms and other patients (mean, 16.5 mm Hg vs. 9.4 mm Hg; P = 0.003). Among Acomm aneurysm cases, the monitored group showed a significantly lower MRM swelling ratio (postoperative MRM area/preoperative MRM area) compared with the control group (1.03 ± 0.10 vs. 1.17 ± 0.15; P = 0.036).

CONCLUSIONS

Myocutaneous flaps can produce unnoticed overpressure on the orbit, resulting in OCS-related blindness during aneurysm clipping surgery, especially in cases involving mandatory lower craniotomy. The continuous extraocular compressive pressure monitoring technique is a simple and effective approach to prevent such a serious complication.

Canthal cutdown for emergent treatment of orbital compartment syndrome

This article evaluates the use of a "canthal cutdown" technique in orbital compartment syndrome in a cadaveric model. Twelve cadaver orbits were used to simulate orbital compartment syndrome using a blood analog solution. Two pressure probes, in different orbital locations, were used to monitor orbital pressure. Pressure was monitored during successive procedures: canthotomy, cantholysis, and canthal cutdown. Orbits were then re-injected with solution, simulating an active orbital hemorrhage, and pressure measurements were recorded over a 10-minute duration. No statistically significant difference was found between the two orbital pressure monitoring devices at each measurement point (p = 0.99). Significant pressure reductions, for both probes, were observed after canthal cutdown compared to initial measurement after injection of 20 mL blood analog (p < 0.001 and p = 0.005). When comparing the orbital pressure following canthotomy and inferior cantholysis versus canthal cutdown, the cutdown procedure provided an additional 74% in orbital pressure reduction (p =0.01). After re-injection of 10 mL of solution and 10 minutes of egress, pressure returned to baseline (probe 1: baseline 7 mm Hg vs. post-cutdown at 10 minutes 7 mm Hg; p = 0.83; and probe 2: 5 mm Hg vs. 5 mm Hg; p = 0.83). The canthal cutdown technique provides further reduction in orbital pressure versus canthotomy and cantholysis alone. The technique may be effective for treatment of static orbital compartment syndrome and temporizing treatment of compartment syndrome from active orbital hemorrhages.

Orbital Disease in Neuro-Ophthalmology

Many abnormalities of the orbit present with neuro-ophthalmic findings, such as impaired ocular motility or alignment, and sensory changes, including optic neuropathy. Comprehensive coverage of all orbital diseases is beyond the scope of this article. This review focuses on diagnosis and management of the most common and the most vision- or life-threatening orbital conditions as well as more recently discovered entities and points of active controversy. These conditions include orbital trauma, vascular disease, inflammatory and infectious diseases, and neoplasms. Common presenting symptoms and associated neuro-orbital diseases also are summarized.

The estimation of postoperative bleeding after reduction of blowout fracture: the effectiveness of negative-pressure drainage system

BACKGROUND

Retrobulbar hemorrhage is a rare complication of midface injury, blepharoplasty, facial fracture surgery, periorbital surgery, and circumbulbar anesthesia. The incidence of postoperative retrobulbar hemorrhage is 0.3% to 4% after the reduction of facial bone fracture. The purpose of this study was to estimate the postoperative bleeding after the reduction of a blowout fracture and to demonstrate the effectiveness of a negative-pressure drainage system with a scalp vein set tube.

METHODS

From January 2006 to July 2013, we handled a total of 1491 cases of blowout fractures. Two of them (0.13%) were diagnosed as retrobulbar hematoma in 2011. After experiencing 2 cases of retrobulbar hematoma, we have been routinely using a scalp vein set tube as a negative-pressure drainage system to check the postoperative blood volume.

RESULTS

From January 2012 to July 2013, a total of 131 patients underwent blowout fracture repair and experienced application of a negative-pressure drainage system. Their mean total drained amount was 12.6 mL; maximum amount was 47.5 mL in the 2 days after the surgery. The maximum drained amount was 41.7 mL on the day of the surgery. All the patients had no cardinal signs or symptoms of retrobulbar hematoma and no complications.

CONCLUSIONS

Retrobulbar hematoma is a rare but critical surgical complication that leads to permanent visual loss. Considering the limited orbital cavity and postoperative edema, the volume of postoperative bleeding is thought to be enough to compress the optic nerve if the blood is not drained. Thus, we recommended a simple negative-pressure drainage system to prevent retrobulbar hematoma.

Orbital compartment: effects of emergent canthotomy and cantholysis

The objective of this study was to determine the effect of orbital decompression procedures on the intraocular pressure (IOP). The orbital compartment syndrome represents an emergency situation. Due to the elevated IOP vision loss may ensue. Several maneuvers including lateral canthotomy are discussed to reduce the IOP. Eight orbits were studied in a fresh frozen cadaveric model (4 specimens). Intraorbital volume was determined by CT volumetry. An orbital compartment syndrome was simulated by injecting viscous material into the orbit. Injected volumes were documented and lateral canthotomy, cantholysis, inferior and superior septolysis were performed. IOP and exophthalmometric measurements were obtained after each intervention. Controlled elevation of IOP was achieved in all specimens. IOP was partially reduced after performing a lateral canthotomy in eight orbits. IOP was significantly and sufficiently decreased under 20 mmHg by inferior cantholysis in seven orbits. An additional superior cantholysis was necessary in two orbits to achieve a complete decompression. Inferior or superior septolysis were not needed to further reduce the IOP. Lateral canthotomy must be followed by an inferior cantholysis to successfully decompress an orbital compartment syndrome in the majority of cases. Occasionally, superior cantholysis may generate additional benefit. Additional inferior and superior septolysis were not shown to provide a beneficial effect when performed after canthotomy and cantholysis.

Inferior orbital septum release compared with lateral canthotomy and cantholysis in the management of orbital compartment syndrome

PURPOSE

The purpose of this study is to assess the utility of inferior orbital septum release compared with lateral canthotomy and inferior cantholysis for the treatment of orbital compartment syndrome.

METHOD

An experimental study design using a cadaver model for orbital compartment syndrome was used to compare the efficacy of inferior orbital septum release with lateral canthotomy and inferior cantholysis. Elevated orbital compartment pressures were created in a total of 10 orbits of 5 fresh cadaver heads. Compartment pressure and intraocular pressure were measured before and after inferior orbital septum release and lateral canthotomy/cantholysis. Additionally, orbital compartment pressure was compared with intraocular pressure at various pressures to assess correlation. Statistical analysis was performed on the collected data for efficacy comparison of the 2 procedures.

RESULTS

Both procedures were found significantly to reduce orbital compartment pressure. Lateral canthotomy and cantholysis was found to lower the pressure by an average of 56 mm Hg as compared with inferior septal release, which resulted in an average of 52-mm Hg reduction. Performing lateral canthotomy and cantholysis first, followed by inferior septal release, resulted in a total pressure reduction of 73 mm Hg, whereas reversing the order resulted in a reduction of 77 mm Hg. Both the first and second steps, regardless of the order of procedure, were found to result in a significant pressure reduction (p = 0.009 and 0.004, respectively). Comparison of a series of data points collected during the induction of the experimental compartment syndrome revealed a statistically significant correlation between orbital compartment pressure and intraocular pressure (Spearman correlation of 0.978 and p value <0.001).

DISCUSSION

The study demonstrates that both lateral canthotomy/cantholysis and inferior orbital septum release are equally effective at reducing orbital compartment pressure. Additionally, the data support an additive, synergistic reduction in compartment pressure when the procedures are performed consecutively. The correlation of orbital compartment pressure to intraocular pressure proves that intraocular pressure can be used as a reliable measurement of orbital pressure during acute changes in orbital mass. The results of this study demonstrate that the use of inferior orbital septum release in conjunction with lateral canthotomy and cantholysis is superior to the gold standard of isolated lateral canthotomy and cantholysis. We hope that the implementation of orbital septum release will result in superior visual outcomes.

Changes in intraocular pressure due to surgical positioning: studying potential risk for postoperative vision loss

STUDY DESIGN

Parallel group design.

OBJECTIVE

Compare the intraocular pressure responses in the prone flat versus prone Trendelenburg's position.

SUMMARY OF BACKGROUND DATA

Postoperative vision loss (PVL) complicates approximately 0.05% of spine surgeries. Prone positioning is considered a risk factor because it increases intraocular pressure, which may decrease perfusion pressure to the optic nerve (perfusion pressure = mean arterial pressure - intraocular pressure [IOP]). The prone Trendelenburg's position is often used during spine surgery; however, its effect on optic nerve perfusion is unknown. The purpose of this study is to compare the IOP responses in the prone flat versus prone Trendelenburg's positions to determine if prone Trendelenburg's position also risks PVL.

METHODS

Twenty subjects randomized into 2 groups. Group 1 lay in the prone flat position (0 degrees). Group 2 lay in the prone Trendelenburg's position (-7 degrees). IOPs were measured with a hand-held applanation tonometer while seated, 1 minute after assuming the group's position (Time 0), and at 10-minute intervals for 60 minutes.

RESULTS

The differences in mean IOPs with respect to positions and time were significant (P = 0.0001, P = 0.000). There was a significant difference between sitting and all other times for both groups. In Group 1, there was a significant difference in IOP between Time 0 and all other times prone flat (P < 0.05). In Group 2, there was a significant difference in IOP between Time 0 all other times prone Trendelenburg (P < 0.05).

CONCLUSION

IOP increases in the prone Trendelenburg's position, and when combined with other factors, may be a risk factor for PVL. The pathophysiology is discussed and suggestions for clinicians are made.

Management of acute orbital hemorrhage with obstruction of the ophthalmic artery during attempted coil embolization of a dural arteriovenous fistula of the cavernous sinus

Because of inability to access a cavernous-carotid fistula through conventional means, a superior ophthalmic vein approach was used to allow access for embolization. Although there was initially robust flow through both the fistula and the ophthalmic artery on angiography, the flow stopped during the procedure, and the patient was found to have an orbital hemorrhage. Immediately on emergent canthotomy and evacuation of the hemorrhage, angiographic evidence of restoration of flow was noted. This finding suggests that vision loss in orbital compartment syndrome may be due to arterial occlusion in some cases, and may be reversible if prompt action is taken.

Non-traumatic orbital haemorrhage

PURPOSE

To establish the incidence of underlying orbital vascular anomalies, the presence of systemic associations and predisposing factors, the natural history and appropriate management of patients with non-traumatic orbital haemorrhage presenting in an orbital clinic.

METHODS

The records of 115 patients with a diagnosis of non-traumatic orbital haemorrhage were reviewed with regard to clinical findings, investigations, management and outcome.

RESULTS

Associated orbital vascular malformations were present in 104 patients (90%). Thirteen (11%) had additional or other predisposing factors (childbirth, prolonged headstands, hypertension or coagulopathies). Six patients (5%) had no predisposing factor. Acute onset painful proptosis, associated with lid swelling or a mass, was the most common presentation. Visual acuity was reduced in 37 patients (32%) at presentation. Excluding eight patients (7%) who underwent surgery for optic nerve compression, spontaneous resolution of the haemorrhage was complete in 62%, partial in 27%, while 4% had no resolution. Final visual acuity was reduced in 23 patients (20%).

CONCLUSION

The majority of bleeds are associated with some form of orbital vascular anomaly. Where no such anomaly can be demonstrated a search for an underlying systemic cause should be performed. Haemorrhages in the young were usually localized whereas those in older patients were diffuse. Orbital imaging, with a combination of computed tomography and magnetic resonance imaging, was helpful in the assessment of these lesions. Most bleeds are venous and self-limiting. Surgical intervention was rarely necessary and should be confined to those with optic nerve compromise or a localized lesion which persists.

Retrobulbar hematoma and blepharoplasty

Retrobulbar hematoma leading to visual impairment is a rare but serious complication associated with elective blepharoplasty. A review of the literature addressing etiology, prevention, and management is presented. Removal of anterior orbital fat associated with traction and rupture of vessels within posterior orbital fat is currently most strongly supported as the cause of retrobulbar hematoma after blepharoplasty. Optic nerve ischemia is identified as the likely cause of visual impairment. Specific recommendations for avoidance and management of acute retrobulbar hematoma are offered. Recent background animal and human research is summarized.