Submacular hemorrhage (SMH) is a term which describes a condition characterized by the presence of blood in the potential space between the retinal pigment epithelium and the retinal layer. The blood comes from fragile new vessels in the choroidal layer, formed in the process of choroidal neovascularization CNV). The patient with SMH suffers acute and painless visual distortion with eventual loss of central vision.
In the majority of patients, CNV is due to age-related macular degeneration. Other causes include:
Submacular hemorrhage is a sight-threatening disorder. When it occurs, the patient may report that there is a sudden blurring of vision, as well as waviness of lines. This phenomenon is called metamorphopsia, and occurs in the center of the visual field, or, in other words, with respect to the object one is directly looking at.
Following a hemorrhage into the submacular space, the outer layers of the retina deteriorate and break down speedily. This is because of:
A submacular hemorrhage is an emergency to be treated by removal of the clot on an urgent basis. The techniques in common use include:
The prognosis of a submacular hemorrhage depends upon the size and extent. A large SMH is often the cause of irreversible vision loss, with or without treatment. If the SMH is an extension of a subretinal hemorrhage, it is often treatable, but complete recovery of normal vision is difficult to achieve. When, as is very often the case, the SMH is a complication of the exudative (“wet”) form of AMD, half of these patients will develop another SMH in less than 3 years from the onset of the first.