Cherry-red spot

Cherry-red spot is a finding on the fundus of the eye that is associated with a variety of underlying conditions, most notably certain metabolic and genetic disorders. It appears as a bright red spot in the center of the macula, surrounded by a region of pale retina. This distinctive appearance is due to changes in the retinal layers, specifically the ganglion cell layer, which becomes opaque in certain diseases, except at the fovea where the absence of ganglion cells leaves the underlying choroidal circulation visible, hence the "cherry-red" appearance.

Causes

Cherry-red spots can be seen in several conditions, including but not limited to:

• Tay-Sachs disease: A genetic disorder, most commonly found in the Ashkenazi Jewish population, characterized by the accumulation of gangliosides in the brain and other tissues.
• Sandhoff disease: Similar to Tay-Sachs, this is a genetic disorder that leads to the accumulation of GM2 gangliosides in the body.
• Niemann-Pick disease: A group of inherited metabolic disorders known as sphingolipidoses, where harmful quantities of fatty substances accumulate in the spleen, liver, lungs, bone marrow, and brain.
• Sialidosis: A rare genetic disorder, also known as mucolipidosis type I, characterized by a deficiency of the enzyme alpha-neuraminidase.
• Central retinal artery occlusion (CRAO): A blockage of the central retinal artery leading to acute vision loss, where the cherry-red spot signifies the ischemic whitening of the retina with a preserved foveal appearance due to its unique blood supply.

Diagnosis

Diagnosis of a cherry-red spot is primarily made through ophthalmoscopy, where the distinctive appearance of the spot in the macula can be observed. Further diagnostic tests may include genetic testing, enzyme assays, and imaging studies to identify the underlying condition causing the cherry-red spot.

Treatment

Treatment of a cherry-red spot focuses on addressing the underlying condition. For genetic disorders, this may involve enzyme replacement therapy, substrate reduction therapy, or supportive care to manage symptoms. In the case of CRAO, immediate treatment is critical to attempt to restore blood flow and minimize permanent damage to the retina.

Prognosis

The prognosis for individuals with a cherry-red spot varies widely depending on the underlying condition. For some, such as those with CRAO, rapid treatment can lead to partial recovery of vision. For others with progressive genetic disorders, the prognosis may be more guarded, focusing on symptom management and quality of life improvements.

See also

• Macula of retina
• Genetic disorder
• Metabolic disorder
• Ophthalmoscopy