Introduction
Acute corneal hydrops is a rare occurrence in corneal conditions where there is sudden corneal swelling due to a tear in the Descemet membrane. This results in decreased vision and eye pain. Acute corneal hydrops typically affects individuals between the ages of 20 and 40. Males may have a higher risk of developing it compared to females. The contribution of family history to its development is inconsistent. In New Zealand, Pacific ethnicity has been linked to a higher risk of hydrops than European descent. In the UK, a higher incidence of keratoconus and acute corneal hydrops has been observed among South Asian and black patients.
What Are the Signs and Symptoms of Acute Corneal Hydrops?
The signs and symptoms of acute corneal hydrops include:
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Sudden, severe eye pain.
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Light sensitivity.
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Redness in the eye.
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Watery eyes.
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Swelling of the cornea.
These symptoms can develop suddenly and worsen rapidly.
What Are the Pathophysiology and Natural History of Acute Corneal Hydrops?
Acute corneal hydrops is caused by a disruption in the barrier function of Descemet's membrane, leading to fluid accumulation in the corneal stroma. The resolution of acute corneal hydrops involves two steps: reattachment of the detached Descemet's membrane to the posterior stroma and migration of the endothelium from the reattached Descemet's membrane to cover the gaps. The time it takes for acute corneal hydrops to resolve and the eventual outcome depends on the depth of the detachment and the size of the break in Descemet's membrane. Most cases of acute corneal hydrops will resolve on their own within two to four months, but in some cases, vision-impairing scarring may occur and require corneal transplantation. Larger disruptions in Descemet's membrane are associated with a longer resolution time, an increased risk of neovascularization, and a poorer visual outcome compared to smaller disruptions.
How to Diagnose This Disorder?
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History - Individuals with acute corneal hydrops present with sudden symptoms, including reduced vision, increased sensitivity to light, and pain. The onset of these symptoms may be spontaneous but may also be triggered by actions such as coughing, sneezing, or eye-rubbing that increase intraocular pressure. Health providers should ask about a patient's history of corneal ectasias, such as keratoconus, and risk factors, such as allergies and eye-rubbing. In some cases, acute corneal hydrops may be the first indication of underlying keratoconus.
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Physical Examination - People with acute corneal hydrops generally have decreased vision. The pressure inside the eye may also be lower because of the swelling in the cornea. During an eye examination, the doctor will check the amount and spread of the swelling in the cornea. The swelling may make it difficult to see other parts of the eye, such as the iris and lens. The doctor may perform a test to check for fluid leakage through the cornea instead of a hole. They may also examine the other eye to see if there are any signs of eye problems or conditions that may have caused the acute corneal hydrops, such as allergies or vernal keratoconjunctivitis.
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Diagnostic Procedures - There are several diagnostic methods that can be used to diagnose ACH. They are Anterior Segment Optical Coherence Tomography (AS-OCT), In-vivo confocal microscopy (IVCM), Ultrasound biomicroscopy (UBM), and Tomography. Each of these methods provides a different type of information about the cornea and can help diagnose and monitor the progress of ACH.
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Differential Diagnosis - The list of possible reasons for a sudden swelling in the cornea, also known as acute corneal hydrops, includes previously undiscovered or known corneal abnormalities such as keratoconus (the most common), keratoglobus, and pellucid marginal degeneration. Other causes of corneal swelling, like an eye infection, inflammation inside the eye, a problem with the layer of cells in the cornea, swelling after surgery, and rejection of a cornea transplant, must also be considered if there is a history or examination findings that suggest these conditions.
What Are the Treatment Options Available for This Disorder?
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Management - The first step in treating acute corneal hydrops (ACH) is usually to wait and see if it goes away on its own. This often happens within two to four months. There is not enough scientific evidence to know the best way to treat ACH, so doctors often use treatments that have worked for other patients. These treatments may include eye drops to lower eye pressure, and eye drops to relax the eye, steroid eye drops, and antibiotics. If fluid leaks from the eye, the doctor may also use eye drops to stop the leak and cover the eye with a patch.
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Surgery -
1. Air or Gas: In cases of acute corneal hydrops (ACH) where the Descemet's membrane (DM) is far from the cornea's stroma, pneumatic descemetopexy may be considered to help reattach the DM. Early injections of air, C3F8 gas or SF6 gas into the anterior chamber of the eye have been found to speed up the resolution of corneal swelling in ACH. Although gas lasts longer in the anterior chamber than air, it requires the eye to be positioned downward for a longer period of time, increasing the risk of complications. The gasses must be used in equal concentrations for them to be effective. Air and gas have been shown to reduce the time it takes for the edema to resolve. Still, there is no improvement in final visual acuity or the need for later corneal transplantation.
2. Compression Sutures: Corneal compression sutures can also be utilized to combine the separated Descemet's Membrane (DM) similar to intracameral air and gas. They are particularly effective when there are intrastromal clefts present. The sutures, placed at a right angle to the DM tear, can be used alone or in combination with intraoperative air injection.
3. Endothelial Keratoplasty: Recent evidence suggests that performing this procedure during the acute phase after ACH can improve vision, speed up corneal clearing, and reduce the need for a full-thickness transplant in the future. Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) techniques have been used to restore the normal anatomy of the posterior cornea after ACH. Long-term monitoring is necessary to detect any potential corneal scarring that may require further surgery.
4. Penetrating Keratoplasty (PKP)/Deep Anterior Lamellar Keratoplasty (DALK): For cases of ACH that cause vision-impairing scars, PKP has been the traditional treatment. However, the success rate of PKP in ACH patients is lower, especially if neovascularization occurs. Due to the long-term complications associated with PKP and the young age of many ACH patients, DALK may be a suitable alternative as it removes the scar while preserving the pre-Descemet layer and the Descemet membrane. However, it is technically challenging to perform in this setting.
What Is the Prognosis of Acute Corneal Hydrops?
The vast majority of ACH patients resolve spontaneously after two to four months. Scar development is possible while the cornea heals. For scars outside the optical axis, this can offer the benefit of flattening the cornea and allowing for a better contact lens fit. Scar formation, on the other hand, frequently impairs eyesight. Cases with larger areas of corneal involvement, longer durations of persistent edema, and neovascularization have a poor prognosis.
Conclusion
In conclusion, acute corneal hydrops is a rare and serious eye condition characterized by sudden corneal swelling due to a tear in the Descemet membrane. It is most commonly seen in individuals between 20 and 40 years old, and there may be a higher risk among males and certain ethnic groups. Symptoms include severe eye pain, blurred vision, light sensitivity, redness, tearing, and corneal swelling. The cause of acute corneal hydrops is a disruption in the barrier function of Descemet's membrane. Diagnosis is made through patient history, physical examination, and diagnostic procedures such as anterior segment optical coherence tomography, in-vivo confocal microscopy, ultrasound biomicroscopy, and tomography. Treatment options include waiting and observing for resolution, using eye drops to lower eye pressure and relax the eye, steroid eye drops, antibiotics and in severe cases, surgery.
