Descemetocele
Descemet’s folds: Folds of DM are observed at the base of the ulcer.
Central clear zone: A transparent area exists in the center of the thinning region.
Anterior bulging: Descemet’s membrane may protrude in a cyst-like manner1).
Management of Descemetocele and Corneal Perforation
Key points at a glance
Section titled “Key points at a glance”1. Management of Descemetocele and Corneal Perforation
Section titled “1. Management of Descemetocele and Corneal Perforation”Descemetocele
Section titled “Descemetocele”A descemetocele is a condition in which an intact Descemet membrane (DM) herniates forward through a defect in the corneal stroma and epithelium1). DM is a transparent, elastic, acellular membrane 8–10 μm thick, secreted by endothelial cells1). It is relatively resistant to proteolysis and biomechanical stress, and protects the endothelium from the destructive process of the stroma1).
Descemetoceles are classified by location as follows1):
- Central: within 5 mm of the corneal center
- Paracentral: 5–8 mm
- Peripheral: 8 mm or more (including the limbus)
Classification by size is based on the maximum diameter: small (<3 mm), medium (3–6 mm), and large (>6 mm)1).
Corneal Perforation
Section titled “Corneal Perforation”When a corneal ulcer extends deep into the stroma and beyond Descemet’s membrane (DM), it leads to corneal perforation. Aqueous humor leaks and the anterior chamber collapses. Causes include infectious, non-infectious, and traumatic factors.
Conservative or surgical treatment is selected based on the size, location, duration, and condition of the cornea at the perforation site.
Q
What is the difference between a descemetocele and corneal perforation?
A
A descemetocele is a condition where Descemet’s membrane bulges forward while remaining intact, representing a “pre-perforation” state. Corneal perforation occurs when Descemet’s membrane also ruptures, leading to aqueous humor leakage. A descemetocele carries a high risk of perforation and requires urgent intervention.
2. Main Symptoms and Clinical Findings
Section titled “2. Main Symptoms and Clinical Findings”
Tobias Röck, Karl Ulrich Bartz-Schmidt, Daniel Röck Management of a neurotrophic deep corneal ulcer with amniotic membrane transplantation in a patient with functional monocular vision: A case report 2017 Dec 15 Medicine (Baltimore). 2017 Dec 15; 96(50):e8997 Figure 1. PMCID: PMC5815707. License: CC BY.
Clinical photograph of the eye showing a corneal ulcer fluorescing with fluorescein staining, along with corneal neovascularization and conjunctival injection.
Subjective Symptoms
Section titled “Subjective Symptoms”- Sudden vision loss: Occurs with perforation or descemetocele formation
- Eye pain: Varies in intensity depending on the degree of infection or inflammation
- Excessive tearing: May accompany aqueous humor leakage
Clinical Findings (Findings Confirmed by Physician Examination)
Section titled “Clinical Findings (Findings Confirmed by Physician Examination)”Corneal perforation
Uveal prolapse: The iris becomes incarcerated in the defect.
Positive Seidel test: Dilution and outflow of fluorescein are observed.
Shallow anterior chamber or flat anterior chamber: The anterior chamber disappears due to aqueous humor leakage.
Uveal prolapse or a positive Seidel test is a definitive diagnostic finding of corneal perforation. However, if uveal prolapse occludes the defect, the Seidel test may be false negative.
Delayed diagnosis can lead to enlargement of corneal damage, endophthalmitis, secondary glaucoma or cataract, and even loss of the eye.
3. Causes and Risk Factors
Section titled “3. Causes and Risk Factors”Corneal ulcers are broadly classified into those occurring in the central area and those in the peripheral area. Central ulcers are often infectious, while peripheral ulcers are often non-infectious.
Infectious Causes
Section titled “Infectious Causes”| Category | Main causative microorganisms |
|---|---|
| Bacterial | Pseudomonas aeruginosa, Staphylococcus, Streptococcus pneumoniae, Moraxella, Neisseria gonorrhoeae |
| Fungal | Fusarium, Aspergillus, Candida |
| Viral | Herpes simplex, Herpes zoster |
Contact lens (CL) wear is the greatest risk factor for microbial keratitis in the United States 7). Overnight wear (including orthokeratology) is a major infection risk 7). Gram-negative bacteria (Pseudomonas, Moraxella, Serratia) are common in CL wearers.
Pseudomonas keratitis progresses alarmingly fast. An initial small round abscess forms a ring abscess within days and perforates from the center. The cornea melts due to proteases produced by the bacteria.
Fungal keratitis caused by filamentous fungi tends to progress into the deep layers, presenting with hypopyon and corneal endothelial plaques 6). As infection spreads, severe melting may eventually lead to perforation 6).
When keratitis complicates conjunctivitis caused by gonococcus, corneal perforation occurs at a high rate, requiring caution 5).
Inflammatory causes
Section titled “Inflammatory causes”- Rheumatoid arthritis: Associated with peripheral corneal ulcer (similar to Mooren’s ulcer), rapidly thinning and may lead to perforation
- Systemic lupus erythematosus (SLE), Granulomatosis with polyangiitis
- Mooren’s ulcer: Deep excavated ulcer at the corneal periphery
Other causes
Section titled “Other causes”- Trauma: Penetrating injury, chemical injury, surgery
- Exposure keratitis: Corneal protection failure due to lagophthalmos
- Corneal degeneration/ectasia: Keratoconus (acute hydrops), Terrien marginal degeneration
- Dry eye-related: Sjögren syndrome, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, GVHD
4. Diagnosis and examination methods
Section titled “4. Diagnosis and examination methods”Seidel test
Section titled “Seidel test”This is an essential test for diagnosing corneal perforation. Apply a sterile fluorescein strip moistened with a small amount of sterile saline to the suspected perforation site and observe under cobalt blue light. If fluorescein is diluted and flows out, the test is positive.
Pressure on the eyeball may enlarge the perforation, so minimize pressure during the test.
Anterior segment optical coherence tomography (OCT)
Section titled “Anterior segment optical coherence tomography (OCT)”This is useful for detailed evaluation of corneal structure1). Even when clinical visualization is hindered by necrotic material or mucoid discharge, it can depict true stromal thickness and DM bulge1). Serial scans allow monitoring of the healing process.
Microbiological examination
Section titled “Microbiological examination”If infectious keratitis is the cause, smear microscopy and culture of lesion scrapings are essential. Ideally, specimens should be collected before antimicrobial treatment.
- Smear microscopy: Evaluate bacterial morphology and staining characteristics with Gram stain6)
- Culture: Inoculate onto blood agar, chocolate agar, and Sabouraud agar (for fungi)6)
- Fungal culture: Incubate at both 37°C and room temperature for at least 2 weeks6)
- Fungiflora Y staining: Useful for specific staining of fungi
Q
What is the Seidel test?
A
This is a test to check for aqueous humor leakage from the cornea using fluorescein dye. The appearance of fluorescein diluted by aqueous humor flowing out (positive finding) can be observed under cobalt blue light. It is one of the most important tests for definitive diagnosis of corneal perforation.
5. Standard Treatment
Section titled “5. Standard Treatment”The choice of treatment is determined based on the size, extent, location of the perforation, degree of stromal infiltration, visual prognosis, and underlying disease. In many cases, multiple treatments are performed simultaneously or sequentially.
Conservative Treatment
Section titled “Conservative Treatment”- Bandage contact lens (BCL): Useful for non-infectious impending perforation or small perforation without uveal prolapse
- Aqueous humor production suppressants: Lower intraocular pressure and reduce outflow from the defect
- Frequent lubricating eye drops, punctal occlusion, tarsorrhaphy: Promote re-epithelialization for ulcers associated with aqueous tear deficiency dry eye
- Anticollagenase drugs: Systemic tetracyclines suppress collagen degradation by inhibiting mucous membrane pemphigoid
- Vitamin C: Stimulates collagen production, especially useful in alkali injuries
- PROSE (scleral lens): In high-risk surgical cases, non-surgical management with scleral lenses is an option4)
Tseng et al. (2024) reported successful non-surgical management for 7 years with PROSE therapy for a Descemetocele secondary to ocular GVHD, maintaining corrected visual acuity of 20/504). The incidence of corneal perforation associated with oGVHD is estimated at 1-4%4).
Infection Control
Section titled “Infection Control”If an infectious corneal ulcer is the cause, infection control of the underlying disease is the top priority.
- Bacterial: Fluoroquinolone eye drops (e.g., levofloxacin, moxifloxacin) are the mainstay; in severe cases, combination of vancomycin + ceftazidime may be used6)7)
- Fungal: For filamentous fungi, pimaricin (5% eye drops, 1% ointment) is first-line6). For filamentous fungi other than Fusarium species, voriconazole 1% eye drops are recommended6). In severe cases, subconjunctival or intrastromal injections are used6)
- Gonococcal: Ceftriaxone 1 g intramuscular single dose is the CDC-recommended first-line treatment5)
Che Ku Amran et al. (2024) reported managing a corneal perforation due to gonococcal keratoconjunctivitis with cyanoacrylate adhesive + BCL + ceftriaxone 1 g intramuscular injection, achieving infection control after 2 months5).
Surgical Treatment
Section titled “Surgical Treatment”| Perforation Size | Recommended Treatment |
|---|---|
| <3 mm | Tissue adhesive or AMT |
| >3 mm | PKP or patch graft |
| Total cornea | Corneoscleral transplant1) |
- Cyanoacrylate adhesive: Considered for perforations <3 mm. It has bacteriostatic action and lasts longer than fibrin glue. It is thought to suppress polymorphonuclear leukocyte and collagenase production, halting the corneal melting process. Success rate for perforations <3 mm is 86%.
- Amniotic membrane transplantation (AMT): Used for impending perforation or perforations <3 mm. It promotes epithelial healing, reduces inflammation, and minimizes scarring. Success rate is 70–90%, with average epithelial healing time of 3–4 weeks.
- Penetrating keratoplasty (PKP): Indicated for perforations >3 mm, anterior chamber loss with iris prolapse, and cases where other treatments have failed. Visual improvement is achieved in 90% of eyes. The rejection rate is approximately 20%.
Kusano et al. (2023) reported a case of severe microbial keratitis where the entire cornea became a descemetocele (total corneal descemetocele)1). Anterior segment OCT confirmed a corneal thickness of 37 μm, and corneoscleral transplantation was performed, successfully preserving the eyeball1). This is considered the largest descemetocele reported1).
- Tenon’s capsule patch graft: Reported for use in corneal perforations up to 6 mm3)
Shekhawat et al. (2022) reported a technique using a Tenon’s capsule patch graft combined with a vascularized conjunctival flap for a paracentral corneal perforation (1 mm)3). At 4 months postoperatively, uncorrected visual acuity was 20/25 with minimal astigmatism3). The robust wound healing response from Tenon’s capsule fibroblasts and the vascular supply from the conjunctival flap promoted healing3). This procedure can be performed even in settings with limited access to corneal donor tissue3).
- One-bite mini-keratoplasty: A technique in which a corneal patch is inserted with a single suture for small perforations of about 1 mm2)
Kato et al. (2021) reported good results with one-bite mini-keratoplasty for a paracentral corneal perforation (1 mm) caused by a metallic foreign body, achieving postoperative corrected visual acuity of 180/200 and corneal astigmatism of 0.6 diopters2). A re-perforation at 17 months was also managed with the same technique, maintaining good visual function for over 2 years2).
- Conjunctival flap: Performed for chronic, refractory ulcers. Total conjunctival flaps such as the Gundersen flap are considered for eyes with poor visual prognosis.
- Conjunctival resection: Performed for marginal corneal ulcers secondary to autoimmune diseases.
Q
Should I choose adhesive or surgery?
A
For perforations less than 3 mm that are not near the limbus and have a well-formed anterior chamber, cyanoacrylate adhesive may be the first choice. Adhesive is also useful as a temporary measure before penetrating keratoplasty (PKP). For perforations larger than 3 mm or with anterior chamber loss, adhesive is difficult to manage and PKP is indicated. The treatment is determined individually based on the size, location, and underlying disease of the perforation.
Q
Is emergency surgery necessary for corneal perforation?
A
Corneal perforation is an ophthalmic emergency. If left untreated, it can lead to endophthalmitis, secondary glaucoma, cataract, and blindness. However, not all cases require emergency surgery. Small perforations may be managed with bandage contact lenses or adhesives, and in infectious perforations, antibiotic treatment may be given for 24–48 hours before planning penetrating keratoplasty (PKP).
6. Pathophysiology and Detailed Pathogenesis
Section titled “6. Pathophysiology and Detailed Pathogenesis”Corneal ulcer begins with epithelial defect and progresses to the stroma. When stromal melting extends deeply and Descemet’s membrane (DM) is exposed, a descemetocele forms, and further rupture of DM leads to perforation.
Role of Proteases
Section titled “Role of Proteases”In experimental keratitis caused by Pseudomonas aeruginosa, descemetocele formation has been shown to directly correlate with alkaline protease, total protease, and elastase activity 1). High protease-producing strains (102, 115, 118) induced massive stromal destruction, descemetocele formation, and perforation even with few inflammatory cells in the presence of Ca²⁺ and Mg²⁺ 1). Leukocyte proteases also contribute to corneal degeneration, but their presence alone does not necessarily lead to descemetocele formation 1).
Characteristics of Descemet’s Membrane
Section titled “Characteristics of Descemet’s Membrane”DM is resistant to proteolysis and biomechanical stress, so it remains intact for a period even when the surrounding stroma melts 1). This property gives rise to the “pre-perforation stage” known as descemetocele. However, lacking sufficient tensile strength, DM eventually herniates forward 1).
Progression of Infectious Keratitis
Section titled “Progression of Infectious Keratitis”Filamentous fungi tend to progress not only on the corneal surface but also into the deeper layers 6). When hyphae break through DM and reach the posterior corneal surface, they form an endothelial plaque 6). Progression leads to severe melting and perforation.
Neisseria gonorrhoeae has the ability to adhere to and invade corneal epithelium via pili 5). Within one hour of inoculation, it is taken into vacuoles within epithelial cells, and after 24 hours, epithelial thickness is markedly reduced 5). This process progresses through epithelial, stromal, and ulcerative keratitis to perforation 5).
7. Latest Research and Future Perspectives (Investigational Reports)
Section titled “7. Latest Research and Future Perspectives (Investigational Reports)”New Surgical Techniques
Section titled “New Surgical Techniques”A technique combining Tenon’s capsule patch graft with a vascularized conjunctival flap has been reported 3). The vascular supply from the conjunctival flap resulted in faster healing (complete recovery of corneal stromal thickness at 6 weeks) compared to conventional Tenon’s capsule patch graft 3). It is expected to be useful in low-resource settings where corneal donor tissue is not available 3).
One-bite mini-keratoplasty is a simple technique for small perforations of about 1 mm, inserting a corneal graft with a single 10-0 nylon suture 2). It is reported to induce less astigmatism compared to conventional lamellar keratoplasty 2).
Non-surgical management with scleral lenses
Section titled “Non-surgical management with scleral lenses”PROSE (Prosthetic Replacement of the Ocular Surface Ecosystem) therapy is gaining attention as an option for long-term management of descemetocele in patients at high risk for surgery 4). The design bridges over the corneal dome, protecting the cornea and providing continuous lubrication and oxygen supply 4). In corneal ectasia, the PROSE group has been reported to be superior to the corneal transplant group in mean visual acuity and speed of visual recovery 4).
8. References
Section titled “8. References”- Kusano M, Mohamed YH, Uematsu M, et al. Whole Corneal Descemetocele. Medicina. 2023;59:1780.
- Kato Y, Nagasato D, Nakakura S, et al. A Case of Paracentral Corneal Perforation Treated with One-Bite Mini-Keratoplasty. Turk J Ophthalmol. 2021;51:55-57.
- Shekhawat NS, Kaur B, Edalati A, et al. Tenon patch graft with vascularized conjunctival flap for management of corneal perforation. Cornea. 2022;41:1465-1470.
- Tseng AM, Heur M, Chiu GB. Sustained descemetocele management with Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) treatment. Am J Ophthalmol Case Rep. 2024;36:102092.
- Che Ku Amran CKH, Ngoo QZ, Awis Qarni F. A Rare Case of Corneal Perforation Secondary to Gonococcal Keratoconjunctivitis. Cureus. 2024;16(11):e74312.
- 感染性角膜炎診療ガイドライン（第3版）作成委員会. 感染性角膜炎診療ガイドライン（第3版）. 日眼会誌. 2024.
- American Academy of Ophthalmology Cornea/External Disease Preferred Practice Pattern Panel. Bacterial Keratitis Preferred Practice Pattern. Ophthalmology. 2024.