Terson syndrome refers to a condition in which intraocular hemorrhage occurs after subarachnoid hemorrhage (SAH), subdural hemorrhage, or intracerebral hemorrhage. The most common forms of intraocular hemorrhage are vitreous hemorrhage and subinternal limiting membrane hemorrhage, and bleeding can also occur in various layers of the retina around the optic disc and macula (preretinal, intraretinal, subretinal). 1)
In 1900, French ophthalmologist Albert Terson first reported vitreous hemorrhage associated with subarachnoid hemorrhage. Since then, intraocular hemorrhage accompanying intracranial hemorrhage has been known as Terson syndrome.
The incidence after traumatic brain injury (TBI) is reported to be approximately 3.1%, which is lower than that of SAH (19.3%) and intracerebral hemorrhage (9.1%), but due to the large number of TBI patients, the absolute number cannot be ignored. 1)
The amount and location of hemorrhage vary among patients, ranging from mild preretinal hemorrhage alone to massive vitreous hemorrhage that prevents fundus visualization. Hemorrhage can occur in the preretinal, intraretinal, subretinal, and vitreous spaces. 1)12)
Not all. In prospective studies, intraocular hemorrhage was observed in 19.3% of SAH patients. Associations with severity and increased intracranial pressure have been reported, and ophthalmologic evaluation is important if visual loss or floaters occur after SAH. 1)9)12)
The main subjective symptom of Terson syndrome is visual loss that occurs after intracranial hemorrhage. When vitreous hemorrhage is massive, it causes sudden and severe visual loss, making fundus visualization impossible. Patients may also complain of floaters. Since symptoms of intracranial hemorrhage (severe headache, impaired consciousness, nausea) are prominent, ocular symptoms are often overlooked. 12)
It can occur unilaterally or bilaterally. In SAH patients with impaired consciousness, complaints of visual loss are often absent, making ophthalmologic screening important.
Initial Findings
Subinternal limiting membrane hemorrhage (preretinal hemorrhage): Observed around the optic disc and macula in the early stage. The hematoma appears as a well-demarcated, dark red elevation.
Mild vitreous hemorrhage: The amount of bleeding may allow fundus visualization. This stage is expected to resolve spontaneously.
Intraretinal and subretinal hemorrhage: Hemorrhage may be seen in various layers from the optic disc to the macula.
Advanced Findings
Massive vitreous hemorrhage: Extensive bleeding into the vitreous cavity may prevent fundus visualization and cause significant vision loss.
Epiretinal membrane: Organization of hemorrhage can lead to epiretinal membrane formation. It is the most frequent complication of Terson syndrome, reported in 15–78% of cases. This complication greatly affects visual prognosis.
Retinal detachment and proliferative vitreoretinopathy: These may accompany vitreous hemorrhage and worsen visual prognosis. 12)
In Terson syndrome, vitreous hemorrhage is the central pathology, but bleeding can involve multiple layers.
| Type of Hemorrhage | Characteristics | Location |
|---|---|---|
| Vitreous hemorrhage | Most common; takes long to resolve | Vitreous cavity |
| Sub-internal limiting membrane hemorrhage and subhyaloid hemorrhage | Their simultaneous presence can form a double ring sign | Sub-internal limiting membrane and subhyaloid |
| Retinal hemorrhage | Appears as flame-shaped or dot hemorrhages | Intraretinal |
Double ring sign is a fundus finding where sub-internal limiting membrane (sub-ILM) hemorrhage and subhyaloid hemorrhage coexist, forming a double contour13). Long-term complications such as epiretinal membrane, retinal detachment, and proliferative vitreoretinopathy have been reported, so follow-up is necessary even after hemorrhage absorption12). Depending on reports, frequencies are noted as epiretinal membrane 15–78%, retinal/perimacular folds approx. 20%, retinal detachment approx. 9%, and ghost cell glaucoma approx. 4%.
It is a finding where inner sub-ILM hemorrhage and outer subhyaloid hemorrhage coexist, appearing as a double ring13).
Even after spontaneous absorption of vitreous hemorrhage, if vision does not improve, complications such as epiretinal membrane or macular edema should be evaluated with OCT, and treatment plan should be determined individually12).
For mild vitreous hemorrhage, spontaneous absorption may be awaited. On the other hand, vitrectomy is considered in bilateral cases, severe unilateral vitreous hemorrhage, or when hemorrhage does not absorb after an observation period. In infants and children, early vitrectomy should be considered due to the risk of visual deprivation amblyopia. Observation is appropriate when hemorrhage shows an improving trend or is minimal, when visual prognosis is poor, in unilateral cases with no risk of amblyopia, or when anesthesia risk is high due to general condition. The treatment plan is determined individually based on visual function, general condition, severity of hemorrhage, and complications.12)
Intracranial hemorrhages that cause Terson syndrome are as follows.
The presence of Terson syndrome can be an indicator of poor prognosis reflecting the severity of SAH, which is an important clinical feature. SAH patients with Terson syndrome have significantly higher mortality compared to those without. A systematic review reported mortality rates of 43% vs 9% (odds ratio 4.8) 7), another report 28.6% vs 2.0% 8), and a study related to intracranial pressure (ICP) reported an odds ratio of 45.0. 9) Lower Glasgow Coma Scale (GCS) scores and higher Hunt and Hess classification and Fisher grade are associated with a higher likelihood of Terson syndrome. 8,9)
The diagnosis of Terson syndrome is made according to the following procedure.
| Examination Method | Main Evaluation Items | Remarks |
|---|---|---|
| Slit-lamp microscopy | Anterior segment, vitreous opacity | Performed under mydriasis |
| Fundus examination | Preretinal hemorrhage, vitreous hemorrhage | Not possible with severe opacity |
| B-scan ultrasonography | Retinal detachment, vitreous opacity | Considered when fundus visualization is not possible |
| OCT | Sub-internal limiting membrane hemorrhage, epiretinal membrane | Useful when the ocular media are clear |
| Fluorescein angiography | Vascular lesions, ischemic areas | Performed when the ocular media are clear |
When proliferative changes are present, evaluate with consideration of retinal detachment, subretinal proliferation, and epiretinal membrane. If fundus visualization is poor, use B-mode ultrasound to confirm retinal complications. 12)
A uniform screening protocol has not been established. In patients with SAH, acute intracranial hypertension, or unexplained visual symptoms, fundus examination aids diagnosis; if fundus visualization is poor, B-mode ultrasound can be added. The timing of examination should be determined by neurosurgery and ophthalmology based on the patient’s general condition and ocular symptoms. 12)
Treatment for Terson syndrome is determined by the severity of vitreous hemorrhage, laterality (unilateral/bilateral), patient age, duration, and presence of complications. The main options are observation and vitrectomy.
| Condition | Treatment Strategy |
|---|---|
| Mild hemorrhage with improving trend | Consider observation |
| Bilateral hemorrhage with significant visual impairment | Consider vitrectomy |
| Hemorrhage not resolving after observation period | Consider vitrectomy |
| Suspected complications such as retinal detachment | Vitreoretinal specialist determines surgical indication |
Even when observation is chosen, if the fundus is not visible, B-mode ultrasound should be used to assess for retinal complications. 12)
Vitrectomy (pars plana vitrectomy: PPV) removes vitreous hemorrhage. For Terson syndrome secondary to TBI, vitrectomy has been reported to improve visual acuity early after surgery in many cases 2,5). Studies in pediatric cases also show good anatomical and functional outcomes after vitrectomy 6).
Additional procedures during vitrectomy are determined individually based on complications such as epiretinal membrane, retinal detachment, and proliferative vitreoretinopathy. These complications can affect postoperative visual acuity 10)12).
The timing of surgery is determined based on the patient’s general condition, extent of hemorrhage, unilateral or bilateral involvement, complications, and the course of spontaneous absorption. Studies after TBI and multicenter studies have shown no significant difference in final visual acuity when comparing groups before and after 3 months or 90 days. Therefore, it cannot be uniformly stated that final visual acuity is better if surgery is performed within 90 days. 2)11)
In multiple case series, visual acuity improved in 21/22 eyes postoperatively, with 16 of 21 eyes reaching 0.5 or better. 10) A multicenter study also showed significant improvement from logMAR 1.57 to 0.53. 11) While prioritizing systemic management of acute SAH, multidisciplinary collaboration is important to avoid missing the window for ophthalmic intervention.
The timing of surgery is determined individually based on the patient’s general condition, amount of hemorrhage, unilateral or bilateral involvement, course of spontaneous absorption, and complications. If symptoms are mild and improving, observation is appropriate; for bilateral cases or non-absorbing cases, surgery is considered. Existing studies have not shown a significant difference in final visual acuity around 90 days, so the decision is made in consultation with ophthalmology while prioritizing neurosurgical treatment. 2)11)12)
The pathogenesis of Terson syndrome has not been established. A widely discussed theory suggests that a rapid increase in intracranial pressure causes cerebrospinal fluid to move into the optic nerve sheath, compressing the central retinal vein and retinochoroidal veins, leading to increased venous pressure and intraocular hemorrhage. 12)
This theory proposes that acute intracranial hypertension due to subarachnoid hemorrhage compresses the central retinal vein within the optic nerve. As a result, central retinal venous pressure increases, causing rupture of retinal capillaries and venules, leading to vitreous hemorrhage. This theory emphasizes the mechanism by which rapid changes in intracranial pressure are transmitted to intraocular vessels, and is consistent with findings that the severity of SAH (degree of intracranial pressure elevation) correlates with the incidence of Terson syndrome.
In intracranial pressure (ICP) monitoring studies, all patients with Terson syndrome had ICP exceeding 20 cmH₂O, with a median of 40 cmH₂O (compared to 15 cmH₂O in those without). However, these are small studies and do not establish a single mechanism. 9)
Intraocular hemorrhage may resolve spontaneously, but can also be complicated by epiretinal membrane, proliferative vitreoretinopathy, and retinal detachment. Since the course varies by case, continuous evaluation of hemorrhage absorption and retinal complications is necessary. 12)
Fundus examination in patients with SAH, acute intracranial hypertension, or unexplained visual symptoms is useful for diagnosing Terson syndrome. However, there are insufficient comparative studies to uniformly determine the target, timing, and method of examination, and coordination based on the patient’s general condition remains a challenge. 12)
Existing post-TBI studies and multicenter studies have not shown significant differences in final visual acuity when using 3 months or 90 days as a cutoff. Larger, prospective studies comparing the period of waiting for spontaneous absorption with surgical timing are needed. 2)11)
