Subhyaloid Hemorrhage, B-Scan, Retina Findings, Causes, Preretinal vs Vitreous Hemorrhage, Treatment

Content:

• What is Subhyaloid Hemorrhage?
• B-Scan
• Retina Findings
• Causes
• Preretinal vs Vitreous Hemorrhage
• Treatment

What is Subhyaloid Hemorrhage?

Subhyaloid hemorrhage is a type of retinal bleeding that occurs between the posterior hyaloid face of the vitreous and the internal limiting membrane (ILM) of the retina. It is sometimes referred to as a preretinal hemorrhage, depending on its exact location. This accumulation of blood appears as a well-demarcated, dome or boat-shaped red area on fundoscopic examination, often overlying the macula or posterior pole.

Patients typically present with sudden painless vision loss, blurring, or a dark spot in their visual field. The severity of visual impairment depends on the size and location of the hemorrhage. Subhyaloid hemorrhages can occur in one or both eyes and may be associated with systemic or ocular vascular conditions. Early diagnosis is crucial, as persistent hemorrhage can lead to toxic effects on the retina and potential long-term vision loss.

B-Scan

A B-scan ultrasound is often used in cases where the view of the fundus is obscured by dense hemorrhage. It helps in differentiating between subhyaloid, preretinal, and vitreous hemorrhages and also rules out associated retinal detachment or mass lesions. The B-scan shows the hemorrhage as an echogenic, well-defined collection adjacent to the retinal surface.

In subhyaloid hemorrhage, the posterior vitreous face may be visible as a thin line separating the hemorrhage from the vitreous cavity. This imaging technique is especially useful when media opacity prevents direct visualization using ophthalmoscopy. It provides essential diagnostic clarity to guide management and intervention decisions.

Retina Findings

On retinal examination, subhyaloid hemorrhages often appear as sharply bordered, boat-shaped or horizontal fluid levels due to gravity settling of the blood. The ILM may act as a barrier, giving the hemorrhage a smooth anterior surface. Macular involvement is common and correlates with more significant visual symptoms.

Retina findings may also reveal additional signs of the underlying cause, such as microaneurysms, neovascularization, or signs of trauma. Over time, the blood may break through into the vitreous cavity or resorb spontaneously. Chronic cases may lead to epiretinal membrane formation or retinal toxicity due to hemoglobin breakdown products.

Causes

Subhyaloid hemorrhages can result from a wide variety of systemic and ocular conditions. Common causes include proliferative diabetic retinopathy, retinal vein occlusion, Valsalva retinopathy (sudden increased intrathoracic pressure), trauma, blood dyscrasias, or hypertension. In young healthy individuals, Valsalva maneuvers are a classic trigger.

In older patients, vascular pathologies such as diabetic retinopathy and venous occlusions are more frequent culprits. Less common causes include Terson syndrome (subarachnoid hemorrhage-related), ocular tumors, and iatrogenic complications after procedures. Identifying the underlying cause is essential for both ocular treatment and systemic management.

Preretinal vs Vitreous Hemorrhage

Preretinal and subhyaloid hemorrhages are often used interchangeably, though anatomically the subhyaloid space lies between the ILM and posterior hyaloid. Preretinal hemorrhages can occur either in the subhyaloid space or beneath the ILM. These are typically well-circumscribed and may have a horizontal fluid level.

Vitreous hemorrhage, by contrast, occurs within the vitreous cavity itself, leading to more diffuse opacification, “cobweb”-like floaters, and obscured retinal detail. B-scan ultrasound helps differentiate these entities. This distinction is clinically important because treatment options and prognostic implications differ for subhyaloid vs vitreous hemorrhages.

Treatment

Treatment of subhyaloid hemorrhage depends on its cause, size, and location. Small hemorrhages may resolve spontaneously over weeks to months with observation. During this time, monitoring for complications like retinal detachment or persistent visual impairment is important.

For large or visually significant macular hemorrhages, Nd:YAG laser membranotomy can be performed to create a small opening in the ILM, allowing the blood to drain into the vitreous cavity for faster resorption. In other cases, pars plana vitrectomy may be required, particularly if there is associated vitreous hemorrhage or traction. Treating the underlying cause (e.g., controlling diabetes or managing hypertension) is crucial for long-term outcomes.