Clinical Symptoms of Corneal Edema
Corneal edema occurs due to improper endothelial pump function. It is one of the most common complications found after cataract surgery. The different causes of this endothelial dystrophy are divided into four categories:
- Mechanical injury
- Concurrent eye disease
- Chemical injury
Symptoms Of Corneal Edema
The various symptoms of corneal edema include:
- Foreign body sensation
- Poor vision
- Halos around point sources of light
Physical Effects Of Corneal Edema
As central corneal edema develops, vision will decrease proportionally. Examination using slit lamp reveals folds in the Descemet membrane. It also reveals the overall thickening of the peripheral and central cornea. Vesicles and bullae can be seen on the corneal surface at more advanced stages of pseudophakic bullous keratothapy (PBK).
Cornea guttata may be seen in patients with predisposing corneal problems. Guttate excrescences appear as golden brown confluent endothelial lesions on slit lamp examination.
Causes Of Corneal Edema
The different causes of corneal edema are as follows:
- Posterior polymorphous dystrophy
- Congenital hereditary endothelial syndrome
- Acute narrow-angle glaucoma
- Herpetic disciform keratitis
- Chandler syndrome
A marked reduction in endothelial cell counts can be associated with surgical trauma at the time of cataract surgery.
Endothelial cell loss of about 4-10% is seen in the modern techniques of cataract extraction (for example, phacoemulsification). However, wide variations in cell loss is observed in individual patients.
Endothelial cell loss has been associated with density of nucleus, cataract incision size and location, and total ultrasound energy used.
Sometimes corneal dystrophyies are overlooked in the preoperative exam, where finding a cornea guttata is quite difficult.
The choice of interocular irrigating fluid can have a huge effect on postoperative corneal edema. Inflammation like uveitis and iritis can affect the endothelial function.