From the Guidelines
Corneal edema is most commonly related to endothelial dysfunction, elevated IOP, and/or intraocular inflammation. The causes of corneal edema can be multifactorial, and a careful ophthalmologic examination is necessary to determine the most likely cause 1.
Common Causes of Corneal Edema
- Endothelial dysfunction
- Elevated intraocular pressure (IOP)
- Intraocular inflammation
- Fuchs corneal dystrophy
- Trauma from eye surgery
- Contact lens overwear
- Acute angle-closure glaucoma
- Viral infections like herpes simplex keratitis
- Chemical injuries
- Inflammatory conditions such as uveitis
- Endothelial cell damage from diabetes
- Toxic reactions to eye medications
- Congenital disorders like congenital hereditary endothelial dystrophy
The underlying mechanism of corneal edema involves compromised endothelial cell function, leading to fluid accumulation in the corneal stroma and epithelium, which disrupts the normally precise arrangement of collagen fibrils and causes light scattering, resulting in blurred vision, halos around lights, and painful sensitivity to light 1.
Management of Corneal Edema
- Lowering the IOP may be helpful when it is elevated or at the upper end of the normal range
- Topical carbonic anhydrase inhibitors should not be first-line therapy because of their potential to interfere with the endothelial pump
- Topical corticosteroids may be used to control inflammation
- Bandage contact lenses may be used to alleviate symptoms of microcystic or bullous epithelial disease
- Scleral lenses may be useful to provide improved visual outcomes and symptom improvement in severe cases with advanced edema or scarring 1.
From the Research
Causes of Corneal Edema
- Corneal edema is a common sign of acute or protracted corneal disease of various aetiologies 2
- Endotheliitis, defined as inflammation of the corneal endothelium, may disrupt endothelial function and cause subsequent visual changes, including corneal edema 3
- Glaucoma and its treatment can cause damage to the corneal endothelium, leading to corneal edema 4, 5, 6
- The mechanisms involved in glaucoma-associated damage to the corneal endothelium include intraocular pressure, glaucoma medications, surgical glaucoma management, mechanical forces, and alterations in the aqueous environment 4
- Topical medical therapy, laser procedures, and both traditional surgeries (trabeculectomy and tube-shunts) and newer minimally invasive glaucoma surgeries have variable effects on endothelial cell loss, which can contribute to corneal edema 5
- Corneal complications of glaucoma surgery, such as endothelial loss, corneal decompensation, and limbal stem cell deficiency, can also lead to corneal edema 6
Etiology of Corneal Edema
- The etiology of corneal edema is extensive and can be viral, medication-related, procedural, fungal, zoological, environmental, or systemic 3
- Glaucoma and its treatment are significant contributors to corneal edema, with both the disease process itself and its treatment potentially causing damage to the corneal endothelium 4, 5, 6