Corneal guttata are small, droplet-shaped outgrowths on the innermost layer of the cornea, called the endothelium. These bumps are often discovered during a routine eye examination. In early stages, they may not cause noticeable symptoms, but can be associated with certain corneal conditions.
Understanding the Corneal Endothelium
The corneal endothelium is a thin layer of specialized cells on the back surface of the cornea. It maintains corneal transparency by actively pumping fluid from the corneal stroma into the aqueous humor. This mechanism prevents the cornea from swelling with excess fluid, which would otherwise lead to cloudiness and impaired vision.
Endothelial cells generally do not regenerate in humans; instead, remaining cells enlarge to cover any gaps if some cells are lost. This limited regenerative capacity means the health and density of this cell layer are important for clear vision. When corneal guttata form, they disrupt this cell layer, affecting its normal function.
The Link Between Guttata and Fuchs’ Dystrophy
While corneal guttata can be an isolated finding, they are a characteristic sign of Fuchs’ Endothelial Corneal Dystrophy, a progressive eye condition. In this condition, guttata accumulate, leading to gradual loss of endothelial cells. As cell density decreases, the fluid-pumping mechanism becomes less efficient, causing fluid to build up within the cornea.
This fluid accumulation, known as corneal edema, leads to several symptoms. Blurred or hazy vision is common, often more pronounced upon waking and improving throughout the day as fluid evaporates. Other symptoms include light sensitivity (photophobia), halos around bright lights, and a gritty or painful sensation. As the condition progresses, blurred vision may last longer or persist all day.
Diagnosis and Monitoring of Corneal Health
An eye care professional diagnoses corneal guttata through a slit-lamp examination. During this examination, the doctor observes the characteristic droplet-shaped bumps on the posterior surface of the cornea, which may appear as dark lesions or a “beaten metal” appearance. This visual inspection is often sufficient for diagnosis.
Further assessment involves diagnostic tools. Specular microscopy images endothelial cells, allowing analysis of their density, size, and shape, and helps differentiate guttata from other deposits. Pachymetry measures corneal thickness, which helps detect and monitor corneal swelling. For individuals with early-stage guttata who do not experience symptoms, management involves periodic observation and monitoring.
Treatment for Advanced Corneal Guttata
Treatment for corneal guttata is considered when symptoms affect daily life due to corneal swelling. For mild corneal edema, non-surgical options are available to help draw fluid out of the cornea. These include hypertonic saline drops or ointments, such as Muro 128, which create an osmotic gradient to reduce swelling. A gentle hairdryer can also help evaporate excess fluid from the corneal surface, especially in the mornings.
When non-surgical methods are no longer sufficient to manage the symptoms, surgical interventions become an option. Modern surgical approaches, collectively known as endothelial keratoplasty, involve replacing only the diseased endothelial layer rather than the entire cornea. Descemet’s Membrane Endothelial Keratoplasty (DMEK) and Descemet’s Stripping Endothelial Keratoplasty (DSEK) are two common types of these targeted procedures. DMEK involves transplanting an extremely thin graft consisting only of the donor’s Descemet’s membrane and endothelium, while DSEK uses a slightly thicker graft that includes a small amount of stromal tissue. These procedures generally offer faster visual recovery and a lower risk of rejection compared to traditional full-thickness corneal transplants.