cornea plana

Cornea Plana: A Rare Congenital Condition

Cornea plana is a rare congenital condition characterized by an abnormally flat shape of the cornea, resulting in a decreased angle between the cornea and the sclera. This condition can lead to various visual problems, including farsightedness (hyperopia), astigmatism, and poor acuity.

Key Features:

• Flat Cornea: The cornea is flatter than normal, with a radius of curvature less than 43 D.
• Decreased Angle: The angle between the cornea and the sclera is decreased or absent.
• Bilateral Inheritance: Cornea plana is typically inherited in an autosomal dominant pattern, affecting both eyes.

Symptoms:

• Farsightedness (Hyperopia): Mild to moderate farsightedness correctable with glasses or contacts.
• Astigmatism: Presence of astigmatism due to the irregular shape of the cornea.
• Poor Acuity: Reduced visual acuity, particularly in low light conditions.

Causes and Risk Factors:

• Genetic: Cornea plana is a congenital condition, meaning it is present at birth. It is inherited in an autosomal dominant pattern.
• Rare Anomaly: The exact cause of cornea plana is unknown, but it is considered a rare anomaly.

References:

1. [3] Oct 14, 2024 — A rare developmental defect of the eye characterized by usually bilateral absence of the normal protrusion of the cornea from the sclera.
2. [5] Mar 6, 2018 — Cornea plana is a bilateral inherited disorder of the cornea which typically presents with a small flat cornea, hyperopia, and a shallow anterior chamber.
3. [7] Cornea plana is a disease characterized by a flat cornea with a radius of curvature less than 43 D.

Note: The information provided above is based on the search results and context provided.

Cornea plana, also known as corneal flattening or corneal thinning, is a rare congenital condition characterized by a flat cornea. The common manifestations of this condition include:

• Flat cornea: The cornea is flatter than normal, which can cause farsightedness correctable with glasses or contacts.
• Indistinct border between the sclera and cornea: Due to the decreased angle between the two, the border may appear indistinct.
• Early-onset arcus lipoides: A round and opaque thickening located centrally in the cornea can occur early on.
• Low anterior chamber depth: The space between the iris and the cornea is shallower than normal.
• Small corneal diameter: The corneal diameter may be smaller than usual, although it can be difficult to measure due to the scleral tissue.

In more serious cases of cornea plana, a central corneal opacity with iris and pupillary abnormalities can occur. Glaucoma sometimes occurs in adults with this condition [11].

It's worth noting that cornea plana is often associated with other ocular anomalies, such as severe signs and symptoms (e.g., a round and opaque thickening located centrally in the cornea) and more frequent association with other ocular anomalies [6][8][9].

Cornea plana, a congenital condition where the cornea is flattened and the angle between it and the sclera is decreased, can be diagnosed through various diagnostic tests.

• Keratometry: This test measures the curvature of the cornea, which is often abnormal in individuals with cornea plana. According to [5], keratometry or VKS (Video Keratoscope) should be performed for confirmation of the diagnosis.
• Slit-lamp examination: A thorough eye examination using a slit lamp can help identify the characteristic flat shape of the cornea and decreased angle between it and the sclera, as mentioned in [3].
• Scanning the cornea with a penlight: This simple test can diagnose corneal surface irregularities, such as abrasions, which may be associated with cornea plana. According to [7], scanning the cornea with a penlight can help identify these irregularities.
• In vivo confocal microscopy: This advanced imaging technique can characterize changes in the morphology of corneal cell layers in individuals with cornea plana, as studied by [9].

These diagnostic tests are essential for confirming the diagnosis of cornea plana and identifying any associated conditions, such as high refractive error, strabismus, or amblyopia.

Treatment Options for Cornea Plana

Cornea plana, a rare congenital condition affecting the cornea, does not have a specific cure. However, various treatment options are available to manage its symptoms and improve vision.

• Refractive correction: This is the mainstay of treatment for cornea plana. Refractive correction involves using glasses or contact lenses to correct hyperopia (farsightedness) caused by the flat cornea.
• Surgical intervention: In some cases, surgical procedures may be necessary to correct vision problems or prevent complications such as glaucoma. These surgeries can include:
  • Corneal transplantation: This involves replacing the damaged cornea with a healthy one from a donor.
  • Refractive surgery: Procedures like LASIK (Laser-Assisted In Situ Keratomileusis) or PRK (Photorefractive Keratectomy) can be used to correct vision problems.
• Glaucoma management: Since individuals with cornea plana are at a higher risk of developing glaucoma, regular eye exams and monitoring are crucial. Treatment for glaucoma may involve medications, laser therapy, or surgery.

It's essential to note that treatment options may vary depending on the severity of the condition and individual factors. A comprehensive eye examination by an ophthalmologist can help determine the best course of action.

References:

• [4] Management is mainly centered around optically or surgically correcting the developmental anomalies.
• [9] Treatment of congenital corneal clouding or opacity is primarily surgical. After surgery, treatment of amblyopia and optical therapy are helpful.
• [11] Refractive correction and glaucoma management are the mainstays of treatment.

Understanding Differential Diagnosis in Cornea Plana

Cornea plana, also known as corneal flattening, is a rare congenital disorder that affects the shape and curvature of the cornea. When diagnosing this condition, it's essential to consider differential diagnoses, which are alternative conditions that may present similar symptoms.

Key Differential Diagnoses for Cornea Plana

• Sclerocornea: A rare congenital anomaly where the sclera (white part of the eye) and cornea fuse together, leading to a flat corneal curvature.
• Microcornea: A condition characterized by an abnormally small cornea, which can also result in a flat corneal curvature.
• Posterior embryotoxin: A rare congenital anomaly where the posterior part of the cornea is abnormal, leading to a flat corneal curvature.
• Glaucoma: A group of eye conditions that damage the optic nerve, potentially leading to vision loss. In some cases, glaucoma can cause a flat corneal curvature.

Other Conditions to Consider

• Peter's anomaly: A rare congenital disorder where the cornea and lens are abnormal, leading to vision problems.
• Corneal opacities: Abnormalities in the cornea that can affect vision.

Important Considerations for Differential Diagnosis

When diagnosing cornea plana, it's crucial to consider the patient's overall health, medical history, and any systemic malformations. A comprehensive evaluation by an eye specialist is essential to determine the correct diagnosis and develop an effective treatment plan.

References:

• [1] Cornea plana 2 (CNA2) is a congenital disorder that causes the cornea to flatten and the angle between the sclera and cornea to shrink.
• [3] Patients with cornea plana often have high refractive error (high hyperopia) with secondary strabismus and/or amblyopia. These need to be identified and managed.
• [5] The mnemonic STUMPED is helpful for remembering the differential diagnosis for congenital corneal opacities: sclerocornea, tears in Descemet membrane.
• [8] It is most likely to be confused with microcornea but the differential diagnosis, as here described, is definite and not difficult, if the existence of this condition is kept in mind.