Eye Diseases > Cornea

Bullous Keratopathy

Evidence-based assessment and management of corneal edema with epithelial bullae formation. Comprehensive guide covering etiology, pathogenesis, classification, diagnosis, and treatment protocols for optometry practice.

Bullous Keratopathy: Corneal decompensation with epithelial bullae and stromal edema due to endothelial dysfunction

Bullous keratopathy is a painful corneal condition characterized by epithelial and stromal edema resulting from endothelial dysfunction. The condition leads to the formation of epithelial bullae (fluid-filled blisters) that rupture, causing significant pain, foreign body sensation, and vision impairment. It represents the end-stage of corneal endothelial decompensation from various etiologies and may require surgical intervention for definitive management.

Primary Causes

Pseudophakic bullous keratopathy (PBK): Most common cause; endothelial damage from cataract surgery or intraocular lens complications
Aphakic bullous keratopathy (ABK): Following cataract extraction without IOL implantation
Fuchs endothelial corneal dystrophy (FECD): Progressive primary endothelial dystrophy with guttae formation
Surgical trauma: Endothelial damage during anterior segment surgery (glaucoma, corneal, or retinal procedures)
Posterior polymorphous corneal dystrophy (PPCD): Endothelial abnormality with epithelial-like characteristics
Congenital hereditary endothelial dystrophy (CHED): Autosomal dominant or recessive endothelial dysfunction
Iridocorneal endothelial (ICE) syndrome: Abnormal endothelial proliferation with secondary glaucoma
Acute angle closure glaucoma: Severe IOP elevation causing endothelial damage
Herpetic keratitis: HSV or VZV-related endothelial damage
Chemical or thermal burns: Direct endothelial toxicity
Prolonged contact lens wear: Chronic hypoxia leading to endothelial compromise
Traumatic injury: Blunt or penetrating ocular trauma
Toxic medications: Intracameral medications, preservatives in ophthalmic solutions

Mechanism of Development

Endothelial dysfunction: Damage or loss of corneal endothelial cells compromises the barrier and pump functions essential for maintaining corneal deturgescence
Critical endothelial cell density: When endothelial cell count falls below 500-800 cells/mm² (normal: 2000-3000 cells/mm²), decompensation occurs
Pump failure: Decreased Na⁺/K⁺-ATPase pump activity impairs active fluid transport from stroma to aqueous humor
Stromal hydration: Aqueous humor accumulates in the stroma, increasing corneal thickness and causing loss of transparency (normal hydration 78%, increases to >90%)
Epithelial microcystic changes: Stromal edema extends anteriorly, disrupting epithelial basement membrane and cell adhesion
Bullae formation: Fluid accumulates between and beneath epithelial cells, forming bullae that elevate and separate epithelium from Bowman's layer
Bullae rupture: Fragile bullae spontaneously rupture, exposing nerve endings and causing severe pain and foreign body sensation
Chronic changes: Repeated bullae formation and rupture lead to subepithelial fibrosis, pannus formation, and corneal scarring

Pathophysiological Cascade

Endothelial Damage → ↓ Cell Density → Pump/Barrier Failure → Stromal Edema → ↑ Corneal Thickness → Epithelial Disruption → Bullae Formation → Bullae Rupture → Pain & Epithelial Defects → Subepithelial Fibrosis → Corneal Scarring

By Etiology

Pseudophakic bullous keratopathy (PBK): Post-cataract surgery with IOL
Aphakic bullous keratopathy (ABK): Post-cataract surgery without IOL
Primary endothelial dystrophy: Fuchs, PPCD, CHED
Secondary endothelial failure: ICE syndrome, glaucoma, trauma, inflammation

By Severity (Clinical Staging)

Stage	Slit Lamp Findings	Symptoms	Management Direction
Stage 1 — Stromal Edema	Corneal thickening, ground-glass appearance; no epithelial involvement; Descemet's folds may be present	Mild blur; halos around lights; often minimal symptoms	Treat underlying cause; monitor; consider ophthalmology referral
Stage 2 — Epithelial Microcysts	Microcystic intraepithelial oedema; early subepithelial changes; stromal striae	Moderate blur; FBS; diurnal variation (worse on waking)	Preservative-free lubrication; urgent ophthalmology referral
Stage 3 — Bullae Formation	Frank epithelial bullae (0.5–3 mm); epithelial defects after rupture; increased corneal thickness >650 µm	Significant pain (especially with rupture); photophobia; tearing; reduced VA	Urgent referral; OTC lubrication for comfort; bandage CL requires co-management with prescriber
Stage 4 — Chronic Decompensation	Recurrent bullae; subepithelial fibrosis; pannus; corneal neovascularisation; scarring; thickness often >800 µm	Severe chronic pain; markedly reduced VA; high infection risk	Urgent referral; surgical options (DMEK/DSAEK/PK); conjunctival flap if not a surgical candidate

By Onset

Acute: Sudden onset (trauma, acute glaucoma, surgical complication)
Chronic: Progressive deterioration (FECD, chronic endothelial loss)

Surgical Risk Factors

Complicated cataract surgery (prolonged surgery time, hard nucleus extraction)
Anterior chamber IOL placement (iris-fixated or angle-supported lenses)
IOL-corneal touch (particularly with anterior chamber IOLs)
Vitreous loss during surgery
Multiple intraocular procedures
Glaucoma drainage device implantation
Penetrating keratoplasty with multiple graft rejections

Patient-Related Risk Factors

Advanced age (>70 years)
Pre-existing low endothelial cell count (<1500 cells/mm²)
Fuchs endothelial corneal dystrophy
Shallow anterior chamber
Small corneal diameter (<11 mm)
History of uveitis or chronic inflammation
Diabetes mellitus (associated with endothelial fragility)
Glaucoma (especially uncontrolled or angle closure)

Environmental and Iatrogenic Factors

Prolonged use of preserved topical medications
Intracameral medications (particularly non-approved formulations)
Extended wear contact lens use with chronic hypoxia
Chemical or thermal ocular burns
Chronic topical steroid use (associated with glaucoma)

Slit Lamp Biomicroscopy Findings

Epithelial bullae: Fluid-filled blisters on corneal surface, variable size (0.5-3 mm)
Stromal edema: Corneal haze, loss of transparency, ground-glass appearance
Increased corneal thickness: Visible on slit beam examination
Epithelial microcysts: Small intraepithelial fluid vacuoles
Descemet's membrane folds: Vertical or oblique striae in posterior cornea
Epithelial defects: Areas of epithelial loss from ruptured bullae
Subepithelial fibrosis: Gray-white anterior stromal scarring (chronic cases)
Pannus formation: Superficial fibrovascular tissue ingrowth
Corneal neovascularization: Blood vessel ingrowth in severe chronic cases
Reduced endothelial reflex: Abnormal or absent endothelial specular reflection

Associated Findings

Anterior chamber IOL (in PBK cases)
IOL malposition or contact with cornea
Guttae (in Fuchs dystrophy-related cases)
Peripheral anterior synechiae (in ICE syndrome)
Iris atrophy or corectopia (in ICE syndrome)
Conjunctival injection and chemosis
Reduced visual acuity (moderate to severe)

Specular Microscopy Findings

Severely reduced endothelial cell density (<500-800 cells/mm²)
Increased coefficient of variation (polymegethism)
Abnormal cell morphology (pleomorphism)
Guttae (if Fuchs dystrophy present)

Primary Symptoms

Severe ocular pain: Sharp, stabbing pain upon bullae rupture, often worse upon awakening
Foreign body sensation: Persistent gritty, sandy feeling
Photophobia: Marked light sensitivity
Blurred vision: Progressive vision loss due to corneal edema and irregularity
Halos around lights: Particularly noticeable at night
Epiphora (tearing): Reflex tearing from pain and irritation
Recurrent corneal erosions: Episodic acute pain episodes

Temporal Pattern

Diurnal variation: Symptoms typically worse in the morning due to nocturnal corneal hydration (eyelid closure reduces evaporation)
Progressive deterioration: Symptoms gradually worsen over weeks to months
Episodic acute pain: Sudden severe pain with bullae rupture

Impact on Quality of Life

Significant functional visual impairment
Chronic pain affecting daily activities and sleep
Reduced work productivity
Psychological distress and depression
Dependence on pain medications

Ocular Complications

Microbial keratitis: Secondary bacterial, fungal, or viral infection of compromised epithelium
Persistent epithelial defects: Non-healing corneal erosions
Corneal ulceration: Deep stromal involvement with risk of perforation
Corneal scarring and vascularization: Permanent vision loss from chronic edema
Corneal perforation: Rare but vision-threatening complication
Secondary glaucoma: From chronic inflammation or peripheral anterior synechiae
Chronic pain syndrome: Persistent pain despite medical management
Neurotrophic keratopathy: Reduced corneal sensation from chronic disease

Surgical Complications

Graft rejection: Following penetrating or endothelial keratoplasty
Graft failure: Primary or secondary endothelial failure
Glaucoma progression: Post-keratoplasty glaucoma
Cataract formation: Following corneal transplantation
Wound dehiscence: Transplant wound complications

Systemic Impact

Depression and anxiety from chronic pain
Sleep disturbance
Medication dependency (opioid analgesics in severe cases)
Reduced quality of life and functional independence

Associated Systemic Conditions

Diabetes mellitus: Associated with increased risk of endothelial dysfunction and delayed healing; may affect surgical outcomes
Autoimmune disorders: Stevens-Johnson syndrome, ocular pemphigoid, and other cicatrizing conditions can lead to secondary bullous keratopathy
Connective tissue disorders: May be associated with corneal endothelial dystrophies
Herpes simplex/zoster: History of herpetic infection may cause endothelial damage

Genetic Associations

Fuchs endothelial corneal dystrophy: Associated with COL8A2 and TCF4 gene mutations; family history increases risk
Congenital hereditary endothelial dystrophy: Autosomal recessive (SLC4A11) or dominant inheritance patterns
Posterior polymorphous dystrophy: Autosomal dominant (COL8A2, ZEB1, GRHL2 genes)

Medication Considerations

Chronic pain management: May require systemic analgesics; monitor for medication interactions and dependency
Immunosuppression: Post-transplant patients require systemic immunosuppression for graft survival (if keratoplasty performed)
Anticoagulation: Increased bleeding risk during surgical interventions

Note: Bullous keratopathy is primarily a localized ocular condition. Unlike some corneal diseases, it typically does not cause systemic complications. However, underlying systemic conditions may influence disease progression and management outcomes.

Clinical History

Previous cataract or anterior segment surgery
Type and position of intraocular lens (if present)
History of corneal dystrophy or endothelial disease
Previous ocular trauma, inflammation, or glaucoma
Temporal pattern of symptoms (morning worse, progressive deterioration)
Family history of corneal dystrophies
Contact lens wear history

Clinical Examination

Visual acuity: Typically significantly reduced (20/80 to counting fingers)
Slit lamp biomicroscopy:
- Epithelial bullae (pathognomonic finding)
- Stromal edema and thickening
- Descemet's folds
- Epithelial microcysts or defects
- Subepithelial fibrosis (chronic cases)
- Assessment of IOL position
- Evaluation of anterior chamber
Intraocular pressure: Assess for concurrent glaucoma
Dilated fundus examination: Evaluate posterior segment (if view permits)

Diagnostic Imaging and Tests

Pachymetry: Central corneal thickness measurement (normal: 535-565 µm; bullous keratopathy typically >650 µm, often >800 µm)
Specular microscopy:
- Endothelial cell density (ECD): Normal 2,500–3,000 cells/mm² in young adults; physiological decline ~0.6%/year with age. Decompensation threshold: <500–800 cells/mm²
- Coefficient of variation (CV): Normal <30%; CV >30% indicates polymegethism (abnormal cell size variation), a marker of endothelial stress
- Hexagonality (6A): Normal >50% hexagonal cells; 6A <50% indicates pleomorphism, reflecting impaired endothelial regeneration
- Guttae identification: Dark spots on specular image indicating focal Descemet's thickening; pathognomonic for Fuchs endothelial corneal dystrophy
- Pre-operative assessment: ECD <1,000 cells/mm² is a relative contraindication for anterior segment surgery without concurrent endothelial protection
Anterior segment OCT (AS-OCT):
- Corneal thickness mapping
- Visualization of epithelial bullae
- Assessment of Descemet's membrane
- IOL position evaluation
Corneal topography: Assess corneal irregularity and astigmatism
Confocal microscopy: Detailed evaluation of corneal layers and endothelium (if available)
B-scan ultrasonography: If posterior segment view is obscured

Laboratory Studies

Microbial cultures: If secondary infection suspected (corneal scraping for bacteria, fungi)
Genetic testing: For hereditary endothelial dystrophies (if indicated)

Diagnostic Criteria

Essential findings for diagnosis:

Epithelial bullae on slit lamp examination
Stromal edema and corneal thickening
Endothelial cell count <800 cells/mm² (if measurable)
Identifiable etiology (surgical, dystrophic, traumatic, etc.)
Symptoms consistent with corneal decompensation

Singapore Optometry Scope Note: Bullous keratopathy is an end-stage corneal condition that requires urgent ophthalmology referral in all confirmed or suspected cases. In Singapore, optometrists are regulated under the Optometrists and Opticians Board (MOH) and do not hold prescribing rights for medicated eye drops.¹⁶ Within scope for Singapore optometrists: (1) Assessment and documentation — slit lamp evaluation, visual acuity measurement, pachymetry, and symptom monitoring; (2) Non-pharmacological comfort advice — educating patients on the morning warm-air/hair dryer technique and sleeping with head elevated; (3) Preservative-free lubricating drops (unmedicated, over-the-counter) for interim comfort. Beyond optometrist scope in Singapore: all prescription medications including hypertonic saline 5% NaCl (Muro 128®), topical antibiotics, NSAIDs, corticosteroids, and IOP-lowering agents require prescription by an ophthalmologist or registered medical practitioner. Bandage contact lens fitting, while technically within optometric scope, requires concurrent antibiotic prophylaxis coverage from a prescribing practitioner, necessitating co-management. All procedural and surgical interventions — anterior stromal puncture, amniotic membrane transplantation, DMEK, DSAEK, penetrating keratoplasty, and conjunctival flap — are the exclusive domain of ophthalmology.

Medical Management (Conservative/Palliative)

Hypertonic saline solutions:
- 5% NaCl drops (Muro 128®) QID-Q2H while awake
- 5% NaCl ointment (Muro 128®) at bedtime
- Mechanism: Osmotic dehydration of cornea to reduce edema
- Efficacy: Temporary relief, limited long-term benefit
Bandage soft contact lens:
- High Dk/t silicone hydrogel lens for pain relief
- Protects exposed nerve endings
- Risk: Increased infection risk; requires close monitoring
- Prophylactic topical antibiotics may be considered
Topical lubricants: Preservative-free artificial tears QID and ointment qHS
Topical antibiotics: Prophylactic use with bandage contact lens or epithelial defects
Topical NSAIDs or mild steroids: For inflammation control (caution with steroids - may delay healing and increase IOP)
Oral analgesics: For pain management (acetaminophen, NSAIDs; opioids in severe cases)
IOP control: Manage concurrent glaucoma to minimize endothelial stress
Reducing nocturnal corneal edema:
- Use of hair dryer on low/cool setting upon awakening (to promote evaporation)
- Sleep with head elevated

Procedural Interventions (Minimally Invasive)

Anterior stromal puncture:
- Create micro-perforations with fine needle to promote epithelial adhesion
- Temporary pain relief; recurrence common
Debridement of bullae: Removal of loose epithelium to reduce pain
Amniotic membrane transplantation: Promotes healing and reduces inflammation

Surgical Management (Definitive Treatment)

Descemet Membrane Endothelial Keratoplasty (DMEK):
- Gold standard for visual rehabilitation
- Transplantation of donor Descemet's membrane with endothelium
- Best visual outcomes; faster recovery
- Lower rejection rates compared to PK
- Requires good peripheral corneal clarity
Descemet Stripping Automated Endothelial Keratoplasty (DSAEK):
- Posterior lamellar keratoplasty with donor endothelium and stroma
- Easier technique than DMEK; more widely available
- Good visual outcomes (typically 20/40-20/60)
- Lower dislocation rate than DMEK
Penetrating Keratoplasty (PK):
- Full-thickness corneal transplant
- Indicated when anterior corneal scarring present
- Longer recovery; higher rejection and complication rates
- May induce significant astigmatism
Removal/exchange of causative IOL: If IOL-corneal touch contributing to edema
Conjunctival flap (Gundersen flap):
- Palliative procedure for pain relief in non-visual eyes
- Covers cornea with conjunctiva; sacrifices vision
- Considered when patient not a candidate for keratoplasty

Emerging/Alternative Therapies

Rho-kinase (ROCK) inhibitors:
- Ripasudil 0.4% (Glanatec®): First commercially approved ROCK inhibitor (Japan, 2014); promotes endothelial cell proliferation, adhesion, and migration
- Y-27632: Investigational agent; demonstrated accelerated endothelial wound healing and enhanced cell density in preclinical and early clinical studies
- Emerging role: Adjunct post-endothelial keratoplasty to promote graft adherence; potential role in mild endothelial insufficiency before decompensation
- Regulatory status: Not yet approved by HSA Singapore or US FDA as primary treatment for corneal endothelial failure; use is currently investigational outside Japan
Cultured endothelial cell injection:
- Donor endothelial cells expanded ex vivo and injected into the anterior chamber with the patient maintained face-down to allow cell adhesion to Descemet's membrane
- 5-year follow-up data (Numa et al., 2021) demonstrates sustained ECD improvement and corneal clarity in early clinical cohorts
- Potential to treat multiple recipients from a single donor cornea; not yet widely available outside specialist research centres
Phototherapeutic keratectomy (PTK): Excimer laser superficial ablation for subepithelial scarring (limited role)

Management Algorithm

Initial assessment: Identify and treat underlying cause (IOL exchange, glaucoma control)
Medical management: Hypertonic saline, lubricants, bandage contact lens
If medical management fails and good visual potential: Refer for endothelial keratoplasty (DMEK or DSAEK)
If anterior scarring present: Consider penetrating keratoplasty
If poor visual potential or not surgical candidate: Palliative measures (bandage lens, anterior stromal puncture, or conjunctival flap)

Referral Guidelines

Ophthalmology Referral — Required in All Cases

Urgent referral (same-day or next available ophthalmology appointment):

All confirmed or suspected bullous keratopathy
Bullae rupture with significant epithelial defect
Suspected secondary microbial keratitis or corneal ulceration
Sudden marked deterioration in vision or pain
Signs of corneal perforation or impending perforation

Routine referral to corneal specialist:

Surgical evaluation for keratoplasty candidacy (DMEK, DSAEK, or PK)
IOL position assessment and possible IOL exchange planning
Co-management: post-operative monitoring, graft rejection surveillance

Natural History

Progressive deterioration: Condition generally worsens without intervention
No spontaneous resolution: Endothelial cells do not regenerate in adults
Chronic pain: Persistent symptoms significantly impact quality of life
Visual impairment: Progressive vision loss from edema and scarring
Eventual stabilization: In some chronic cases, subepithelial fibrosis may reduce bullae formation but at the cost of permanent corneal scarring

Medical Management Outcomes

Limited efficacy: Medical therapy provides only temporary symptom relief
Hypertonic saline: 30-40% of patients report modest improvement; effects wear off quickly
Bandage contact lens: Effective for pain control but requires close monitoring; infection risk ~5-10%
No visual improvement: Medical management does not restore vision

Surgical Outcomes

DMEK:
- Best visual outcomes: 60-70% achieve ≥20/40, 30-40% achieve ≥20/25
- Graft survival: ~95% at 3 years, ~90% at 5 years
- Rejection rate: 5-10% at 5 years (lower than PK)
- Graft detachment requiring rebubbling: 15-30% of cases
DSAEK:
- Visual outcomes: 40-60% achieve ≥20/40
- Graft survival: ~90% at 3 years, ~85% at 5 years
- Rejection rate: 10-15% at 5 years
- Lower dislocation rate than DMEK (5-10%)
Penetrating Keratoplasty:
- Visual outcomes: 30-50% achieve ≥20/40 (more variable)
- Graft survival: ~75-80% at 5 years, ~65-70% at 10 years
- Rejection rate: 20-30% at 5 years (higher than EK procedures)
- Longer recovery (12-18 months for visual stabilization)
Pain relief: >95% of patients experience significant pain relief following successful keratoplasty

Singapore & Regional Context: Singapore National Eye Centre (SNEC) and Singapore General Hospital (SGH) are regional centres of excellence for corneal transplantation, with DMEK adopted into routine practice since the 2010s. The SingHealth Eye Bank supports a high-quality donor tissue supply chain. Ang et al. (2012) documented outcomes for keratoplasty in the Singapore population, highlighting indications specific to Asian eyes including pseudophakic bullous keratopathy as a leading indication.¹⁷ Corneal graft availability in Singapore relies substantially on imported tissue; patients should be counselled that waiting times for donor tissue may apply.

Factors Affecting Prognosis

Favorable factors:
- Early surgical intervention before significant scarring
- Absence of glaucoma or well-controlled IOP
- No history of previous graft rejection
- Younger age (better healing response)
- Clear peripheral cornea
Unfavorable factors:
- Advanced anterior stromal scarring or vascularization
- Concurrent glaucoma (especially if poorly controlled)
- Previous graft failure or multiple rejections
- Active ocular inflammation
- Anterior chamber IOL or malpositioned IOL
- Peripheral anterior synechiae

Long-Term Outlook

With treatment: Endothelial keratoplasty offers excellent pain relief and good visual rehabilitation in most patients
Without treatment: Chronic pain, progressive vision loss, and risk of infection
Graft longevity: May require repeat keratoplasty if graft fails (10-15% at 5-10 years)
Quality of life: Significant improvement in QOL following successful surgery

Overall: Prognosis with modern endothelial keratoplasty techniques (DMEK/DSAEK) is generally excellent for both pain relief and visual rehabilitation. Early referral and appropriate surgical intervention significantly improve outcomes.

Primary Differential Considerations

Fuchs Endothelial Corneal Dystrophy (Pre-bullous Stage)

Similarities: Endothelial dysfunction, corneal edema, morning symptoms

Distinguishing features: Bilateral presentation, corneal guttae on slit lamp, family history, progressive course over years, typically no history of surgery/trauma

Acute Corneal Hydrops (in Keratoconus)

Similarities: Sudden corneal edema, epithelial bullae, pain

Distinguishing features: Acute onset, history of keratoconus, Descemet's membrane rupture visible, typically unilateral, may spontaneously resolve over weeks

Microbial Keratitis

Similarities: Corneal edema, pain, epithelial defects

Distinguishing features: Corneal infiltrate/ulcer present, mucopurulent discharge, anterior chamber reaction, rapid progression, positive cultures

Chemical or Thermal Burn (Acute Phase)

Similarities: Corneal edema, epithelial defects, severe pain

Distinguishing features: Clear history of exposure, limbal ischemia, conjunctival chemosis, acute presentation

Acute Angle Closure Glaucoma

Similarities: Corneal edema (microcystic), eye pain, blurred vision

Distinguishing features: Markedly elevated IOP (>40 mmHg), mid-dilated fixed pupil, shallow anterior chamber, nausea/vomiting, no epithelial bullae, acute onset

Posterior Polymorphous Corneal Dystrophy (PPCD)

Similarities: Endothelial abnormality, may develop edema

Distinguishing features: Bilateral, vesicular/geographic endothelial lesions, usually asymptomatic, may have iris abnormalities, family history

ICE Syndrome (Iridocorneal Endothelial Syndrome)

Similarities: Endothelial dysfunction, corneal edema, may progress to bullae

Distinguishing features: Unilateral, iris abnormalities (atrophy, corectopia, nodules), secondary glaucoma, "beaten metal" or "ICE-cell" endothelial appearance

Herpes Simplex/Zoster Endotheliitis

Similarities: Corneal edema, decreased endothelial function

Distinguishing features: Sectoral or diffuse edema, keratic precipitates, anterior chamber reaction, elevated IOP common, history of herpetic disease, skin lesions (VZV)

Congenital Hereditary Endothelial Dystrophy (CHED)

Similarities: Endothelial dysfunction, diffuse corneal edema

Distinguishing features: Bilateral, present at birth or early childhood, diffuse ground-glass corneal appearance, markedly thickened cornea, no guttae

Contact Lens-Induced Corneal Edema

Similarities: Corneal edema, discomfort, blurred vision

Distinguishing features: History of extended contact lens wear, resolves with lens discontinuation, usually no bullae, microcystic changes, reversible

Corneal Graft Rejection/Failure

Similarities: Corneal edema, reduced endothelial function

Distinguishing features: History of corneal transplant, Khodadoust line (in acute rejection), keratic precipitates on graft, anterior chamber reaction

Key Diagnostic Differentiators

History: Surgical history (PBK/ABK), trauma, dystrophy, inflammation
Laterality: Unilateral (PBK, ABK, ICE) vs bilateral (FECD, PPCD, CHED)
Onset: Acute vs chronic/progressive
IOP: Elevated (glaucoma, ICE) vs normal
Endothelial findings: Guttae (FECD), abnormal cells (PPCD, ICE), reduced count
Bullae presence: Pathognomonic for advanced decompensation

Morning symptoms. Pain and blurred vision are characteristically worse upon awakening due to reduced tear evaporation during sleep (eyelid closure), causing increased corneal hydration overnight. Educate patients to expect this and use the hair dryer technique immediately on waking.

Endothelial cell threshold. Corneal decompensation typically occurs below 500–800 cells/mm². Normal adult density is 2,000–3,000 cells/mm² declining ~0.6%/year physiologically. Pre-operative specular microscopy is essential before any anterior segment surgery.

DMEK vs DSAEK. DMEK provides superior visual outcomes (60–70% ≥20/40) but has higher technical difficulty and graft detachment risk (15–30%). DSAEK is more surgically forgiving but yields slightly lower acuity due to the residual posterior stromal interface.

Hypertonic saline is palliative, not curative. While widely used, 5% NaCl provides only temporary and modest osmotic relief. It does not halt disease progression. Frame it as a comfort measure while awaiting definitive surgical management.

Bandage contact lens caution. Effective for pain control by protecting exposed nerve endings, but therapeutic lenses carry ~5–10% infection risk. Requires prophylactic antibiotic coverage from a prescribing practitioner and close scheduled follow-up.

Always assess IOL position in PBK. Anterior chamber IOLs and malpositioned posterior chamber IOLs cause chronic endothelial trauma. IOL exchange may be necessary before or concurrent with keratoplasty — evaluate on slit lamp and AS-OCT.

Don't delay referral. Early corneal specialist referral is crucial. Chronic bullous keratopathy leads to subepithelial fibrosis and scarring, which complicates surgical outcomes and may necessitate full-thickness PK instead of the preferred endothelial keratoplasty.

Glaucoma control is essential. Elevated IOP accelerates endothelial cell loss and worsens oedema. Prioritise IOP control but avoid preserved topical medications — preservatives (particularly BAK) further damage the already-compromised endothelium.

Pain out of proportion to appearance. Severe, sharp pain on bullae rupture results from direct exposure of sub-basal corneal nerve endings. This differentiates bullous keratopathy from other causes of corneal oedema (e.g., acute angle-closure) where pain is more pressure-related.

Hair dryer technique. Using a hair dryer on low/cool setting directed 30–40 cm from the open eye upon awakening promotes tear evaporation and reduces morning oedema. This simple, safe adjunct can meaningfully improve early-morning comfort.

Use steroids judiciously. Topical corticosteroids reduce inflammation but chronic use may elevate IOP and delay epithelial healing. If used, monitor IOP closely and use the lowest effective frequency. Preservative-free formulations preferred.

Descemetorhexis without graft (DWEK). In select Fuchs dystrophy cases with central guttae but minimal edema, DWEK may allow peripheral endothelial cells to migrate centrally and repopulate the stroma — avoiding donor tissue altogether. Not suitable for bullous keratopathy with established oedema.

Post-operative face-up positioning after DMEK/DSAEK. Patients must maintain supine (face-up) positioning for 24–48 hours post-operatively to facilitate gas-tamponade graft adherence. Counsel patients and carers on this requirement before listing for surgery.

Singapore Optometry Scope Note — Document findings systematically. When assessing a patient with suspected bullous keratopathy, record: slit lamp stage, central corneal thickness (pachymetry), best-corrected visual acuity, IOP, and IOL position. Document referral made, urgency, and any comfort measures initiated. This supports continuity of care and post-operative co-management.

Price MO, Fairchild KM, Price DA, Price FW Jr. Descemet's stripping endothelial keratoplasty five-year graft survival and endothelial cell loss. Ophthalmology. 2011;118(4):725-729.
Gain P, Jullienne R, He Z, et al. Global survey of corneal transplantation and eye banking.JAMA Ophthalmol. 2016;134(2):167-173.
Krachmer JH, Mannis MJ, Holland EJ. Cornea. 4th ed. Philadelphia: Elsevier; 2017.
Stuart AJ, Romano V, Virgili G, Shortt AJ. Descemet's membrane endothelial keratoplasty (DMEK) versus Descemet's stripping automated endothelial keratoplasty (DSAEK) for corneal endothelial failure. Cochrane Database Syst Rev. 2018;6(6):CD012097.
Bourne WM. Biology of the corneal endothelium in health and disease. Eye (Lond). 2003;17(8):912-918.
Feng MT, Price MO, Miller JM, Price FW Jr. Air reinjection and endothelial cell density in Descemet membrane endothelial keratoplasty: five-year follow-up. J Cataract Refract Surg. 2014;40(7):1116-1121.
Hamzaoglu EC, Straiko MD, Mayko ZM, Sáles CS, Terry MA. The first 100 eyes of standardized Descemet stripping automated endothelial keratoplasty versus standardized Descemet membrane endothelial keratoplasty. Ophthalmology. 2015;122(11):2193-2199.
Joyce NC. Proliferative capacity of corneal endothelial cells. Exp Eye Res. 2012;95(1):16-23.
Patel SV. Graft survival and endothelial outcomes in the new era of endothelial keratoplasty.Exp Eye Res. 2012;95(1):40-47.
Price MO, Price FW Jr. Endothelial keratoplasty – a review. Clin Exp Ophthalmol. 2010;38(2):128-140.
American Academy of Ophthalmology Cornea/External Disease Panel. Preferred Practice Pattern® Guidelines. Corneal Ectasia. San Francisco, CA: American Academy of Ophthalmology; 2018.
Melles GR, Ong TS, Ververs B, van der Wees J. Descemet membrane endothelial keratoplasty (DMEK). Cornea. 2006;25(8):987-990.
Terry MA, Shamie N, Chen ES, et al. Endothelial keratoplasty for Fuchs' dystrophy with cataract: complications and clinical results with the new triple procedure.Ophthalmology. 2009;116(4):631-639.
Lee WB, Jacobs DS, Musch DC, et al. Descemet's stripping endothelial keratoplasty: safety and outcomes: a report by the American Academy of Ophthalmology.Ophthalmology. 2009;116(9):1818-1830.
Gorovoy MS. Descemet-stripping automated endothelial keratoplasty. Cornea. 2006;25(8):886-889.
Optometrists and Opticians Board. Optometrists and Opticians Act 2007 (Cap. 213A). Ministry of Health, Singapore; 2007.
Ang M, Mehta JS, Lim F, Bose S, Htoon HM, Tan D. Indications, outcomes, and risk factors for failure in tectonic keratoplasty. Ophthalmology. 2012;119(7):1311-1319.
Tan DT, Dart JK, Holland EJ, Kinoshita S. Corneal transplantation. Lancet. 2012;379(9827):1749-1761.
Okumura N, Koizumi N, Ueno M, et al. ROCK inhibitor converts corneal endothelial cells into a phenotype capable of regenerating in vivo endothelial tissue. Am J Pathol. 2012;181(1):268-277.
Koizumi N, Okumura N, Ueno M, Kinoshita S. New therapeutic modality for corneal endothelial disease using Rho-associated kinase inhibitor eye drops. Cornea. 2014;33(Suppl 11):S25-31.
Numa K, Imai K, Ueno M, et al. Five-year follow-up of first 11 patients undergoing injection of cultured corneal endothelial cells for corneal endothelial failure.Ophthalmology. 2021;128(4):504-514.
Dapena I, Ham L, Melles GR. Endothelial keratoplasty: DSEK/DSAEK or DMEK — the thinner the better? Curr Opin Ophthalmol. 2009;20(4):299-307.
Price MO, Price FW Jr. Descemet membrane endothelial keratoplasty surgery: update on the evidence and hurdles to acceptance. Curr Opin Ophthalmol. 2013;24(4):329-335.
Brunette I, Roberts CJ, Vidal F, et al. Alternatives to eye bank native tissue for corneal stromal replacement. Prog Retin Eye Res. 2017;59:97-130.

Clinical Illustration

Overview

Etiology