Pseudophakic bullous keratopathy is an eye condition that affects the cornea, the clear, dome-shaped front surface of the eye. It typically emerges after cataract surgery, leading to corneal swelling and the formation of tiny blisters. This swelling and blistering can significantly impair vision.
Understanding Pseudophakic Bullous Keratopathy
The cornea is a transparent tissue that plays a significant role in focusing light onto the retina. Its clarity is maintained by a delicate balance of fluid, regulated primarily by the corneal endothelium, a single layer of cells on the innermost surface. These endothelial cells act as a pump, actively transporting excess fluid out of the corneal stroma and back into the aqueous humor.
Damage to these specialized endothelial cells disrupts their ability to pump fluid effectively. Fluid then accumulates within the corneal layers, a condition known as edema. As edema progresses, especially in the epithelial layer, it can lead to the formation of small, fluid-filled blisters or bullae. The term “pseudophakic” indicates this condition occurs in individuals who have undergone cataract surgery and have an artificial intraocular lens (IOL) implanted.
Why It Develops
Pseudophakic bullous keratopathy develops due to damage to the corneal endothelial cells during cataract surgery. Direct trauma from surgical instruments or the intraocular lens during implantation can lead to cell loss.
High energy levels during phacoemulsification, a common cataract removal technique, can also contribute to endothelial cell damage. Additionally, irrigating solutions used during surgery, post-operative inflammation, or elevated intraocular pressure can pose a risk. Individuals with pre-existing corneal conditions, such as Fuchs’ endothelial dystrophy, are at a higher risk.
Recognizing the Signs and Symptoms
Individuals experiencing pseudophakic bullous keratopathy notice a gradual decline in vision following cataract surgery. Blurred or hazy vision is common, often more pronounced upon waking due to fluid accumulation overnight. The cornea may also appear cloudy or hazy.
Patients might also report glare and halos around lights. Discomfort, a foreign body sensation, and pain can arise, especially if bullae on the corneal surface rupture. This rupture can expose nerve endings, leading to sharp pain and increased tearing.
Diagnosis and Treatment Approaches
Diagnosis begins with a comprehensive eye examination. A slit-lamp microscope allows observation of corneal swelling, fluid accumulation, and bullae. The characteristic appearance of the swollen cornea and the presence of blisters are sufficient for diagnosis.
Other diagnostic tools provide detailed information. Pachymetry measures corneal thickness, helping to quantify the extent of swelling. Specular microscopy assesses the health and density of endothelial cells, revealing the number and morphology of these cells. A healthy cornea typically requires a cell count of at least 700 cells/mm² to maintain transparency.
Treatment ranges from conservative management to surgical intervention. Conservative treatments aim to reduce corneal swelling and alleviate symptoms. Hypertonic saline drops or ointments are often prescribed to draw excess water out of the cornea, thereby reducing edema. Therapeutic soft contact lenses can provide comfort and protect the corneal surface from ruptured bullae.
When conservative measures are insufficient, surgical options are considered. Endothelial keratoplasty (EK) is often the definitive treatment, replacing the damaged endothelial layer. Descemet’s Stripping Endothelial Keratoplasty (DSEK) and Descemet’s Membrane Endothelial Keratoplasty (DMEK) are common EK procedures. These involve removing only the diseased endothelial layer and replacing it with a healthy donor endothelium, allowing for faster visual recovery and fewer complications compared to full-thickness transplants.
Penetrating keratoplasty (PK), a full-thickness corneal transplant, involves replacing all layers of the cornea. While historically used, it is now less common due to the success and advantages of EK procedures, which are less invasive and have a quicker recovery time. The goal of treatment is to restore corneal clarity and improve vision.