The condition where blisters form in the epithelial layer of the cornea is called bullous keratopathy. It was previously referred to as bullous keratitis. In reality, it is not an inflammation but a degeneration, resulting from abnormalities in the corneal layers, particularly the endothelial layer, leading to fluid accumulation in the epithelial layer.

bubble_chart Etiology

1. Crystalline bullous keratopathy: such as absolute stage glaucoma, advanced stage uveitis, Fuchs' endothelial dystrophy, and complications like anterior synechia after penetrating keratoplasty.
2. Aphakic bullous keratopathy (ABK): post-cataract surgery vitreous touch to the cornea, intraoperative mechanical injury, chemical injury (saline, BSS), etc.
3. Pseudophakic bullous keratopathy (PBK): early factors mainly include corneal endothelial injury caused by the surgery itself, secondary glaucoma post-surgery, and direct mechanical injury to endothelial cells by the intraocular lens. Late-stage [third stage] factors primarily involve chronic low-grade iritis induced by the intraocular lens touching the iris (incidence rate of 1-10% for anterior chamber and iris-fixated types, and less than 1% for posterior chamber types) and corneal endothelial injury due to aging.

bubble_chart Clinical Manifestations

Edema and swelling occur on the corneal membrane, leading to loss of luster, with one or several large blisters (mostly reaching several millimeters) protruding. These blisters are filled with slightly turbid fluid. Due to friction with the eyelids during blinking, the blisters may rupture. At this point, because the corneal nerves are exposed, the patient experiences severe irritation symptoms such as pain, photophobia, and tearing. The ruptured blisters form epithelial defects or filaments, and the blisters may repeatedly appear and rupture, ultimately resulting in the ingrowth of blood vessels, forming degenerative vascular nebula.

1. Occurs in blind eyes following glaucoma, iridocyclitis, intraocular surgery, or chemical injuries.
2. Symptoms include foreign body sensation, stabbing pain, etc., which persist and do not subside.
3. The corneal epithelium loses its luster, with transparent blisters of varying sizes that may recur after rupture.

bubble_chart Treatment Measures

The treatment of this disease has always been a challenging issue. The main methods include:

1. Drug therapy: Topical application of 50% hypertonic glucose, 90% glycerol, or 5% saline to reduce corneal edema and delay the rupture of bullae.
2. Hydrophilic corneal contact lenses: Wearing these lenses can absorb corneal moisture, reducing or even eliminating bullae. Additionally, they can prevent friction between the eyelid and corneal bullae and alleviate a series of symptoms caused by bullae rupture.
3. Surgical treatment:
   1. Cauterization of the anterior elastic layer.
   2. Gundersen conjunctival flap covering.
   3. Corneal lamellar transplantation or interlamellar implantation of the lens capsule.
   4. Interlamellar cauterization (Qiu Xiaozhi et al., 1991): This procedure creates a thin layer of fibrous connective tissue between the corneal layers to block the forward seepage of fluid in fistula disease.
   5. Penetrating keratoplasty is currently the preferred method for treating this condition. This approach allows for the removal of most corneal lesions and their replacement with normal tissue, including endothelial cells.