A retinal detachment occurs when the light-sensitive tissue at the back of the eye separates from its underlying support layers. This separation prevents the retina from receiving necessary oxygen and nutrients, leading to vision loss. Fundus photography captures detailed images of the retina, allowing eye care professionals to identify and document this condition.
Anatomy of a Normal Fundus Photograph
A healthy fundus photograph presents a consistent reddish-orange coloration, a result of light reflecting off the underlying choroid. Several distinct structures are visible. The optic disc, a circular or slightly oval area, marks where the optic nerve exits the eye and retinal blood vessels converge. It typically appears yellowish-orange to pink with sharp margins.
Branching from the optic disc are the retinal arteries and veins, which supply blood to the retina. Located temporally to the optic disc, the macula is a slightly darker, oval-shaped region responsible for sharp, central vision. Its center, the fovea, is a small depression that provides the highest visual acuity.
Key Visual Indicators of a Retinal Detachment
When a retinal detachment is present, its appearance on a fundus photo differs noticeably from the normal, smooth retinal surface. The detached retina often appears as an elevated, sometimes folded or wrinkled, tissue. This elevated tissue can range from translucent to opaque, depending on the extent and chronicity of the detachment. The normal underlying reddish-orange choroidal pattern becomes obscured or hidden in detached areas.
The accumulation of fluid beneath the retina can cause a significant, dome-like elevation, often described as “bullous.” This three-dimensional lifting of the retina is a hallmark sign of detachment. The detached area may also appear grayish, contrasting with the healthy, attached retina.
Identifying Different Types of Retinal Detachment
Different types of retinal detachment present with distinct appearances on a fundus photo, reflecting their underlying causes.
Rhegmatogenous Retinal Detachment
This is the most common type, occurring when a tear or break in the retina allows fluid from the vitreous cavity to pass underneath the neurosensory retina. On a fundus photo, it is characterized by a corrugated or wavy appearance of the detached retina. The presence of a visible retinal break, such as a horseshoe-shaped tear, often confirms this diagnosis.
Tractional Retinal Detachment
This type results from fibrous scar tissue pulling the retina away from its normal position. Fundus photos typically show fibrous bands or membranes on the retinal surface, causing a concave or “tented-up” elevation of the retina. The detachment often appears less mobile and shallower than rhegmatogenous detachments. This type is frequently associated with conditions like proliferative diabetic retinopathy.
Exudative Retinal Detachment
Also known as serous detachment, this occurs when fluid leaks from blood vessels underneath the retina, accumulating without a retinal break or significant traction. On a fundus photo, it appears as a smooth, dome-shaped elevation of the retina. Unlike rhegmatogenous detachments, no retinal tear is visible, and there are typically no obvious fibrous bands pulling on the retina. The subretinal fluid may shift with changes in patient position.
Post-Treatment Appearance on a Fundus Photo
Following successful treatment for retinal detachment, the fundus photograph provides evidence of the reattached retina and surgical interventions. Pigmented scars from laser photocoagulation, a common treatment to seal retinal tears, appear as dark spots or lines around the treated area. These scars indicate where the laser secured the retina to the underlying tissue.
If a scleral buckle was used, its effect might be visible as a circumferential indentation of the retina. This silicone band, placed around the outside of the eye, helps relieve traction and support the reattached retina. In cases where silicone oil was injected as a temporary internal support, it may appear as a reflective, clear artifact within the vitreous cavity. The presence of these post-operative signs indicates that the retina has been successfully reattached, even though the fundus appearance is permanently altered by the treatment.