Acute Corneal Hydrops

Key Points at a Glance

Acute corneal hydrops (ACH) is an acute corneal edema caused by a tear in Descemet’s membrane (the deep layer of the cornea), allowing aqueous humor to flow into the corneal stroma.
It occurs in corneal ectatic disorders such as keratoconus, keratoglobus, and pellucid marginal degeneration, with an incidence of about 2.4–3% in keratoconus.
Main symptoms include sudden vision loss, eye pain, photophobia, and corneal opacity; eye rubbing is the most common trigger.
Most cases resolve spontaneously within 2–4 months, but corneal scarring, neovascularization, and permanent vision loss may occur.
Intracameral gas injection or compression sutures can shorten resolution to 2–7 weeks.
Infectious keratitis complicates about 2.7% of cases, requiring special attention in patients with atopic dermatitis.

1. What is Acute Corneal Hydrops?

Acute corneal hydrops (ACH) is a rare complication of corneal ectatic disorders. It is a condition in which a tear in Descemet’s membrane and the corneal endothelium allows aqueous humor to rapidly flow into the corneal stroma, causing acute corneal edema.

The most common underlying disease is keratoconus, but it also occurs in keratoglobus and pellucid marginal degeneration (PMD).

Incidence rates are as follows¹⁾:

Keratoconus: approximately 2.4–3%
Pellucid marginal degeneration: 6–11.5%
Keratoglobus: approximately 11%

Age of onset ranges from 5 to 59 years, with a peak in the 20s to 40s¹⁾. The risk in men is up to twice that in women. Ethnic differences are also observed, with higher prevalence in Pacific Islanders in New Zealand and in South Asians and Black people in the UK.

Recent findings indicate that acute corneal hydrops (ACH) does not occur with a Descemet membrane defect alone; a defect in the posterior corneal stroma is also necessary. A report noted that ACH did not occur in 16 eyes with Descemet membrane defects during DMEK, but occurred in all 5 eyes with posterior stromal perforation ¹⁾.

Q How often does acute corneal hydrops occur?

It is reported to occur in approximately 2.4–3% of patients with keratoconus, 6–11.5% of patients with pellucid marginal corneal degeneration, and about 11% of patients with keratoglobus ¹⁾. The risk is higher with more severe corneal ectasia, and special attention is needed in patients with a habit of eye rubbing.

2. Main Symptoms and Clinical Findings

Slit-lamp photograph of acute corneal hydrops

Zemba M, Zaharia AC, Dumitrescu OM. Association of retinitis pigmentosa and advanced keratoconus in siblings. Rom J Ophthalmol. 2020. Figure 1. PMCID: PMC7739560. License: CC BY.

Severe corneal edema and opacity from the center to the lower part are observed, showing the clinical appearance of acute corneal hydrops protruding forward. This corresponds to the understanding of sudden corneal opacity and edema described in the “Clinical Findings” section.

Subjective Symptoms

The main subjective symptoms of ACH are as follows.

Sudden vision loss: Severe visual impairment due to edema of the entire cornea occurs suddenly.
Eye pain: Pain occurs due to epithelial edema and bullae formation.
Photophobia (sensitivity to light): Increases with decreased corneal transparency.
Tearing: Occurs along with pain and photophobia.
Awareness of corneal opacity: The patient may notice the opacity themselves.

Triggers include actions that temporarily increase intraocular pressure, such as eye rubbing, sneezing, coughing, blowing the nose, and vigorous exercise. It often occurs spontaneously.

Clinical Findings

Slit-lamp microscopy reveals conjunctival hyperemia, corneal stromal edema, epithelial edema, intrastromal clefts, and epithelial bullae¹⁾.

The grade classification based on the extent of edema is shown below¹⁾.

Grade 1

Maximum diameter of edema: ≤3 mm

Lesion characteristics: Localized stromal edema, confined to a part of the cornea.

Grade 2

Maximum diameter of edema: 3–5 mm

Lesion characteristics: Moderate extent of edema, may affect the visual axis.

Grade 3

Maximum diameter of edema: >5 mm

Lesion characteristics: Extensive edema, presenting severe opacity including the visual axis. The youngest case (5-year-old girl) reported limbus-to-limbus total corneal edema⁸⁾.

For corneal transparency assessment, a 5-grade classification from Grade 0 (anterior chamber and iris completely invisible) to Grade 4 (completely transparent) is also used¹⁾.

Anterior segment OCT (AS-OCT) can non-invasively visualize Descemet membrane rupture and detachment, intrastromal fluid clefts, and increased corneal thickness¹⁾. The size and depth of the tear are predictive indicators of ACH resolution time. Seidel test may be positive, but this is due to aqueous humor leakage from the edematous cornea, not perforation.

There are reports of ACH occurring in cases complicated by Graves ophthalmopathy, and elevated intraocular pressure and ocular surface inflammation may be risk factors⁷⁾.

3. Causes and Risk Factors

Main Risk Factors

Eye rubbing: The most common risk factor. It causes breaks in Descemet’s membrane due to microtrauma ¹⁰⁾.
Atopic diseases: Patients with atopy have a higher risk of corneal hydrops ¹⁰⁾. Atopic dermatitis is also often associated with keratoconus.
Seasonal allergies: Associated with the onset of hydrops ¹⁰⁾.
Vernal keratoconjunctivitis (VKC): Keratoconus patients with VKC require corneal transplantation earlier ¹⁰⁾.
Connective tissue diseases such as Ehlers-Danlos syndrome and osteogenesis imperfecta: Associated with fragility of Descemet’s membrane ¹⁰⁾.
Down syndrome and learning disabilities: Linked to the habit of eye rubbing.
Steep corneal curvature and corneal thinning: Progression of ectasia increases mechanical stress on Descemet’s membrane.
Elevated intraocular pressure: When corneal expansion force exceeds the resistance of Descemet’s membrane, a break occurs ⁷⁾.
Graves’ ophthalmopathy: Compression by extraocular muscles, intraocular pressure fluctuations due to increased episcleral venous pressure, and ocular surface inflammation may be risk factors ⁷⁾.
History of ACH: There is a risk of development in the contralateral eye ¹⁾.

Regarding the risk of infection, a report indicates that 2.7% (3/112 cases) of ACH cases were complicated by infectious keratitis ⁵⁾. All complicated cases were males with severe atopic dermatitis, with an average age of 46 years. Cultures detected MSCNS and MSSA.

Q Why is the habit of rubbing your eyes dangerous?

Rubbing the eye applies mechanical force to Descemet’s membrane, and in a cornea that is already thinned and ectatic, it can directly trigger a rupture of Descemet’s membrane ¹⁾. Patients with atopic dermatitis are particularly at high risk because they tend to rub their eyes due to itching. If itching occurs, it is important to control symptoms with eye drops or other medications.

4. Diagnosis and Examination Methods

AS-OCT of both eyes in acute corneal hydrops

Sedaghat MR, Momeni-Moghaddam H, Belin MW, et al. Acute Hydrops with Total Corneal Edema in a Very Young Child with Keratoconus: The Youngest Age Reported Case. Case Rep Ophthalmol Med. 2022. Figure 3. PMCID: PMC9391173. License: CC BY.

AS-OCT of the right and left eyes shows diffuse corneal thickening and bulging with irregularity of the posterior surface. This tomographic image demonstrates the evaluation of edema extent and depth in acute corneal hydrops as described in the “Imaging” section.

The diagnosis of ACH is based on clinical findings and supplemented by various imaging tests.

Slit-Lamp Examination

This is the basis of diagnosis. Conjunctival injection, stromal edema, epithelial edema, and intrastromal clefts are identified ¹⁾. A Seidel test is performed to differentiate from perforation.

Imaging Tests

The characteristics of the main examination modalities are shown below.

Examination Method	Main Evaluation Content	Features
AS-OCT	DM rupture, stromal clefts	Non-contact, quantitative
Ultrasound biomicroscopy	Rupture site, corneal thickness	Resolution monitoring
In vivo confocal microscopy (IVCM)	Inflammatory cells, edema	Cellular-level assessment

Anterior segment OCT (AS-OCT): Non-contact visualization of Descemet membrane rupture and intrastromal fluid clefts ¹⁾. Rupture size and depth are predictive of ACH resolution time. It is also useful for assessing the depth of corneal infiltration when infectious keratitis is present ⁵⁾. The PPP states that “in keratoconic hydrops, large Descemet ruptures and central stromal clefts may be present” ⁹⁾. Intraoperative OCT (iOCT) is used for real-time guidance during compression suturing ²⁾.
Ultrasound biomicroscopy (UBM): Allows visualization of the rupture site and intrastromal clefts, as well as measurement of corneal thickness. Resolution can be monitored using the hydrops resolving index (ratio of CT0/CT2.5) ¹⁾.
In vivo confocal microscopy (IVCM): Enables cellular-level assessment of epithelial and stromal edema and detection of inflammatory cells. If inflammatory cells persist for more than 4 weeks, the risk of corneal neovascularization is high ¹⁾.
Corneal topography/tomography: Used for monitoring progression of keratoconus and evaluating unaffected eyes.

Differential Diagnosis

Infectious keratitis: May occur concurrently with ACH (2.7%) ⁵⁾. AS-OCT is useful for simultaneous evaluation of Descemet membrane rupture and depth of corneal infiltration.
Fuchs endothelial corneal dystrophy: Edema due to diffuse corneal endothelial dysfunction. Differentiated by the absence of ectasia.
Uveitis: Secondary corneal edema due to intraocular inflammation. Differentiated by inflammatory findings in the anterior chamber.
Postoperative corneal edema / acute graft rejection: Check for history of surgery or corneal transplantation.

5. Standard Treatment

Treatment for ACH begins with conservative management; surgical treatment is considered when improvement is poor or early resolution is needed.

Conservative Treatment (Initial Management)

The following medications are used¹⁾⁹⁾.

Hypertonic saline eye drops (5% NaCl): The main agent to promote corneal dehydration.
Corticosteroid eye drops: Suppress inflammation and neovascularization (e.g., prednisolone acetate 1%, loteprednol 0.5%).
Mydriatic/cycloplegic agents: Relieve ciliary spasm (e.g., cyclopentolate 1%).
Intraocular pressure-lowering agents: Suppress aqueous humor production and reduce pressure on the cornea (e.g., brimonidine 0.15%, timolol 0.5%).
Prophylactic antibiotics: Prevent secondary infection (e.g., moxifloxacin 0.5%).
Bandage contact lens (BCL): Alleviate symptoms (pain, photophobia).

Spontaneous resolution with conservative treatment takes 2–4 months (maximum 5–36 weeks)¹⁾. In eyes that have undergone corneal cross-linking (CXL), resolution is significantly faster, with complete resolution reported within 3 weeks⁷⁾.

Surgical Treatment

Performed to promote early resolution, relieve symptoms, and minimize corneal scarring.

Intracameral Gas Injection

Pneumatic descemetopexy: Air, SF6, or C3F8 is injected into the anterior chamber to unfold and reattach the edge of Descemet’s membrane through a tamponade effect ¹⁾.

Resolution time: 2 to 7 weeks (significantly shorter than 64 to 117 days with conservative treatment).

Reinjection rate: Air 77.8%, SF6 66.7%, C3F8 0 to 35.7% require reinjection.

Compression Sutures

Compression sutures: Sutures compress and close the Descemet’s membrane tear. Includes full-thickness sutures (FTS) and partial-thickness sutures (PTS) ²⁾.

Resolution time: Literature review reports 1 hour to 45 days; most within 2 weeks ²⁾.

Combined with intracameral air: Complete resolution within 2 weeks reported with 3 FTS plus air (50% anterior chamber fill) ³⁾.

Corneal Transplantation

Descemet stripping automated endothelial keratoplasty (DSAEK)/Descemet membrane endothelial keratoplasty (DMEK): Considered for large Descemet’s membrane tears ¹⁾.

Deep anterior lamellar keratoplasty (pDALK): Can achieve DM closure, corneal curvature recovery, and visual recovery in a single surgery.

Penetrating keratoplasty (PKP): Performed for visually significant scarring after ACH. Long-term graft survival after ACH is lower than in non-ACH cases ³⁾.

A representative postoperative eye drop regimen after compression sutures is shown ³⁾.

Medication	Dose/Frequency
moxifloxacin 0.5%	4 times/day
prednisolone acetate 1%	taper as appropriate
NaCl 5%	once at bedtime

Q Will it heal naturally without treatment?

Many cases resolve within 2 to 4 months with conservative treatment alone ¹⁾. However, corneal scarring and neovascularization may persist after resolution, leading to permanent visual impairment. Intracameral gas injection or compression sutures can shorten resolution to about 2 weeks and minimize scar formation. It is important to discuss treatment options with your doctor.

Q What is the surgery to inject gas into the anterior chamber (pneumatic descemetopexy)?

This is a surgery in which air or a special gas (SF6, C3F8, etc.) is injected into the anterior chamber, and the tamponade effect supports the torn Descemet’s membrane from the inside to promote reattachment ¹⁾. It can shorten the resolution time from 64–117 days with conservative treatment to 2–7 weeks. However, pupillary block glaucoma or the need for reinjection may occur.

6. Pathophysiology and Detailed Mechanism of Onset

Mechanism of Descemet’s Membrane Tear

Conventionally, the following pathway has been assumed: microtrauma such as eye rubbing → Descemet’s membrane tear → aqueous humor penetrates into the stroma → separation of lamellar layers → edema ¹⁾.

Recent studies have shown that Descemet’s membrane defect alone does not cause ACH; a defect in the posterior corneal stroma is also essential ¹⁾. This finding is important for explaining why ACH occurs only in cases of severe corneal ectasia.

Histological Features

In full-thickness corneal transplant (PKP) specimens of ACH corneas, loosely packed stromal lamellae are observed. Laminin and type IV collagen are localized adjacent to the rolled-up Descemet’s membrane, and this is thought to play an important role in endothelial cell migration and re-endothelialization ¹⁾.

Distribution of Corneal Edema

The anterior one-third of the corneal stroma remains mildly swollen due to lamellar interweaving. The posterior two-thirds consist of non-interwoven unidirectional fibrils and can swell up to three times ⁷⁾.

Resolution Mechanism

Adjacent corneal endothelial cells migrate to the Descemet’s membrane tear, restore endothelial pump function, leading to corneal dehydration, and finally repair is completed by scar formation ¹⁾. Compression sutures physically approximate the edges of Descemet’s membrane, promoting endothelial cell migration.

Studies using in vivo confocal microscopy have shown that cases where inflammatory cells persist for more than 4 weeks have a high risk of corneal neovascularization ¹⁾.

Early Resolution in CXL-Treated Eyes

Varshney et al. (2021) reported a case of ACH complicating keratitis after CXL ⁷⁾. In the CXL-treated cornea, resolution occurred rapidly in 21 days, significantly shorter than the usual 2–4 months. The mechanism was suggested to be enhanced collagen crosslinking by CXL → increased interlamellar cohesive strength in the anterior stroma → increased resistance to swelling. Crosslinked corneas have higher resistance to enzymatic digestion, which is thought to contribute to early resolution.

Mechanism of Complications

Corneal perforation: High intraocular pressure, eye rubbing, and use of steroid eye drops increase the risk of perforation in edematous cornea¹⁾.
Microbial keratitis: Epithelial defects, contact lens wear, entropion, and steroid use are risk factors¹⁾. Atopic patients have a higher carriage rate of resistant bacteria including MRSA, and infections tend to be more severe⁶⁾.

7. Latest Research and Future Perspectives (Investigational Reports)

iOCT-guided compression sutures

A technique using intraoperative OCT (iOCT) to adjust suture depth and tension in real time has been reported.

Kaur et al. (2025) performed iOCT-guided partial-thickness compression sutures (PTS, target depth 50–60%) in 7 cases (median age 16 years, preoperative corneal thickness 1120–2363 μm)²⁾. Suturing was performed while confirming stromal compaction with a “caterpillar” appearance via iOCT; all cases resolved within 2 weeks, and sutures were removed after 8–12 weeks. PTS showed efficacy comparable to full-thickness sutures (FTS) with a lower risk of endothelial damage.

A literature review (19 studies) reported that resolution time for compression sutures ranged from 1 hour to 45 days, with most resolving within 2 weeks²⁾.

Two-stage surgery (thermokeratoplasty + deep anterior lamellar keratoplasty)

Liu et al. reported a two-stage procedure: TKP-assisted epikeratophakia (first stage for Descemet membrane repair) followed by DALK using the same graft (second stage) after 2.1±0.7 months to achieve visual recovery²⁾.

Lamellar wedge resection

Petrelli et al. performed lamellar wedge resection for corneal perforation after ACH when cyanoacrylate adhesion was unsuccessful²⁾. This achieved refractive improvement while avoiding corneal transplantation.

Intracameral platelet-rich plasma (PRP) injection

Alio et al. performed an anterior chamber injection of 0.3 ml of Enriched Platelet-Rich Plasma (EPRP) in cases unresponsive to SF6, achieving resolution within one week ¹⁾. The mechanism was presumed to be promotion of endothelial cell regeneration by growth factors.

mini-DMEK (Small-Diameter Descemet Membrane Endothelial Keratoplasty)

For cases with large Descemet membrane tears, a method using a 5 mm diameter small DMEK patch to temporarily seal the tear has been reported ¹⁾. Cases have been reported where the cornea naturally achieved deturgescence even after partial graft detachment.

ACH after ICRS Implantation

Ontiveros-Holguín & Pacheco-Padrón (2022) reported a case of ACH and ICRS migration after intracorneal ring segment (ICRS) implantation ⁸⁾. It resolved after 8 weeks with conservative treatment alone. This is considered the first report of ACH after ICRS implantation recovering with only conservative management.

Q What is iOCT-guided compression suture?

This is a compression suture performed while confirming suture depth and tension in real time using intraoperative OCT (iOCT) ³⁾. Since it allows objective control of suture depth, which previously relied on experience, effective corneal compression can be achieved while reducing the risk of endothelial damage. In the report by Kaur et al., all cases resolved within two weeks.

8. References

Bafna RK, Kalra N, Asif MI, et al. Management of acute corneal hydrops - Current perspectives. Indian J Ophthalmol. 2024;72(4):495-507.
Abtahi MA, Zeidabadinejad H, Aminizade M, et al. Advancements in surgical modalities for corneal hydrops: A comprehensive review. J Int Med Res. 2025;53(1):3000605241310405.
Kaur M, Balaji A, Titiyal JS, et al. Intraoperative optical coherence tomography-guided compression sutures in acute corneal hydrops - Surgical technique and review of literature. Indian J Ophthalmol. 2025;73(12):1779-1785.
Elnaggar F, Alsharif H, Almutlak M, et al. Management of acute corneal hydrops using compression sutures and intracameral air injection. Am J Case Rep. 2024;25:e944517.
Kitazawa K, Kozaki R, Yamashita Y, et al. Corneal infection complicating acute corneal hydrops in keratoconus patients. Am J Ophthalmol Case Rep. 2025;38:102303.
Dogan AS, Gurdal C, Celikay O, et al. Acute corneal hydrops in keratoconus patients with Graves’ orbitopathy. Beyoglu Eye J. 2021;6(4):331-334.
Varshney T, Goel S, Bafna RK, et al. Rapid spontaneous resolution of corneal hydrops in post-CXL keratitis. BMJ Case Rep. 2021;14:e246141.
Ontiveros-Holguín A, Pacheco-Padrón J. Successful management of corneal hydrops and intrastromal corneal ring segment (ICRS) migration following ICRS implantation for keratoconus. Am J Case Rep. 2022;23:e936897.
Sedaghat MR, Momeni-Moghaddam H, Belin MW, et al. Acute hydrops with total corneal edema in a very young child with keratoconus: the youngest age reported case. Case Rep Ophthalmol Med. 2022;2022:2381703.
American Academy of Ophthalmology. Corneal Edema and Opacification Preferred Practice Pattern. AAO; 2023.

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