Overview
The cornea is a clear tissue located in front of the iris. Its main functions are as a barrier to protect the inner eye and to focus light on the retina. It is composed of 5 layers. The 3 main layers include the epithelium (outermost barrier layer), the stroma (the middle layer providing the refractive power), and the endothelium (responsible for pumping fluid out of the stroma so that the cornea does not swell and cloud over).
Sagittal view of a healthy eye (left) and frontal image of a healthy eye (right).
Guttata represent tiny deposits of collagen, like scar tissue, above the endothelial cells found bilaterally (both eyes). These spots are invisible to the naked eye. They signify poorly functioning or dying endothelial cells. Because we are born with more endothelial cells than needed, we can have many guttata before developing any symptoms related to Fuchs' dystrophy.
Fuchs' dystrophy occurs when there are enough failing endothelial cells that fluid starts accumulating in the corneal stroma and the cornea starts to swell and cloud over. If enough fluid enters the cornea it can rupture through the epithelium and cause pain and light sensitivity. Fuchs' dystrophy is a genetically inherited condition that typically affects women more than men and is very loosely correlated to glaucoma.
White dots representing endothelial guttata in the cornea (left), frontal view of guttata (right).
Signs and Symptoms
Signs
Guttata: microscopic collagen deposits on the back of the cornea.
Fuchs' dystrophy: swollen and cloudy cornea.
Symptoms
Guttata: none.
Fuchs' dystrophy: decreased vision and halos/glare around lights that are worse in the morning and may improve throughout the day, pain and light sensitivity.
Causes and Risk Factors
Genetics or complications during cataract surgery.
Prevention and Treatment
Prevention
There are no known preventative measures.
Treatments
- Saline ointment (draws out excess fluid from cornea).
- Blow dryer (lowest heat setting) to the eyes from arm’s length away for 2 minutes.
- Dilating drops, antibiotics and a bandage contact lens if fluid is causing rupturing in the epithelial layer.
- Endothelial transplant surgery.
Prognosis
Guttata are, not too uncommonly, found in patients who never develop Fuchs' dystrophy. Guttata themselves do not cause pain or decreased vision or glare. If there is enough endothelial cell atrophy (enough guttata) the patient will develop Fuchs' dystrophy. It is a condition that can permanently affect someone’s vision and may require surgery. It is typically managed with saline ointment and a blow dryer at first. Once those treatment stop working, a transplant surgery is needed. The surgery typically can improve a patients’ vision to 20/50 but its 5-year rejection rate is 15% in healthy eyes and 50% in glaucomatous eyes (eyes with glaucoma).