peripheral degeneration of cornea

Peripheral hypertrophic subepithelial corneal degeneration (PHSCD) and Pellucid marginal degeneration (PMD) are two distinct conditions that affect the periphery of the cornea.

Characteristics:

• PHSCD: A bilateral, slowly progressive condition characterized by peripheral, symmetric, and subepithelial fibrotic lesions in the periphery and mid-periphery of the cornea [1][3]. The lesions are often elevated and can be sausage-roll-shaped [10].
• PMD: A noninflammatory, peripheral corneal thinning disorder characterized by a peripheral band of thinning, usually in the inferior cornea [8][15]. The ectatic zone lies above the point of maximum corneal thinning.

Key Features:

• Both conditions are typically bilateral and affect the periphery of the cornea.
• PHSCD is associated with subepithelial fibrosis, while PMD is characterized by peripheral corneal thinning.
• Both conditions can cause visual disturbances, but the exact symptoms may vary depending on the individual case.

References:

[1] Maust and Raber (2003) reported 6 patients with PHSCD, who presented with ocular irritation symptoms and no predisposing corneal or systemic disease [1]. [8] PMD is a bilateral, noninflammatory condition characterized by peripheral corneal thinning [8]. [10] The original term used by Maust and Raber to describe PHSCD is well-named and describes a primary disorder with a peripheral, circumferential, elevated zone of corneal opacification [10]. [15] PMD is a noninflammatory, peripheral corneal thinning disease characterized by a peripheral crescentic band of thinning, usually in the inferior cornea [15].

Peripheral degeneration of the cornea, also known as pellucid marginal corneal degeneration (PMCD), can manifest in various ways. Here are some common signs and symptoms:

• Corneal thinning: The most distinctive feature of PMCD is the peripheral thinning of the cornea, which can be localized or extensive.
• Astigmatism: Degeneration may lead to a high degree of against-the-rule or oblique astigmatism, affecting vision quality.
• Subepithelial and/or anterior stromal opacities: Mild, punctuate subepithelial and/or anterior stromal opacities are often the first signs of degeneration, typically appearing superiorly.
• Clear area between opacities and limbus: A clear area is usually present between the opacities and the limbus (the border between the cornea and the sclera).
• Ocular irritation symptoms: Some patients may experience ocular irritation symptoms, such as foreign body sensation or need for artificial tear substitutes.
• Corneal edema: In advanced cases, persistent corneal edema can occur due to failure of the corneal barriers.

It's essential to note that these signs and symptoms can vary in severity and presentation among individuals. If you're experiencing any unusual eye symptoms, it's crucial to consult an eye care professional for a proper evaluation and diagnosis.

References:

• [1] Krachmer J: Pellucid marginal corneal degeneration. Arch Ophthalmol 96:1217–1221, 1978
• [11] Pellucid marginal corneal degeneration (PMCD) is a bilateral, noninflammatory, peripheral corneal thinning disease.
• [15] Pellucid marginal corneal degeneration (PMD) is a rare ectatic disorder which typically affects the inferior peripheral cornea in a crescentic fashion.

Based on the provided context, it appears that there are several treatment options available for peripheral corneal degeneration.

• Lubricating eye drops: These can be used to help manage symptoms and reduce discomfort. [4]
• Anti-inflammatory medications: These may be prescribed to reduce inflammation and promote healing. [4]
• Hypertonic saline: This is a type of solution that can be used to help stabilize the cornea and reduce swelling. [4]

It's worth noting that these treatments are often used in conjunction with other therapies, such as surgical options, to manage peripheral corneal degeneration.

In addition, some studies have suggested that corneal transplantation may be a viable option for treating certain types of peripheral corneal degeneration. However, this would depend on the specific characteristics of the condition and the individual's overall health. [11]

It's also important to note that early diagnosis and treatment can help manage symptoms and prevent further progression of the disease. Regular check-ups with an eye care specialist are essential for monitoring the condition and adjusting treatment plans as needed. [15]

The differential diagnosis for peripheral degeneration of the cornea, also known as Terrien marginal degeneration, involves a range of conditions that can cause similar symptoms and physical exam findings.

Key Conditions to Consider:

• Peripheral Ulcerative Keratitis: This is an inflammatory condition that causes thinning and ulceration of the peripheral cornea.
• Mooren Ulcer: A rare, non-inflammatory condition characterized by peripheral corneal thinning and ulceration.
• Marginal Corneal Infiltrates: A condition where there are infiltrates (collections of white blood cells) in the peripheral cornea.
• Interstitial Keratitis associated with infectious disease: An inflammatory condition caused by an infection that affects the interstitial tissue of the cornea.
• Neurotrophic Ulcus: A type of corneal ulcer caused by nerve damage.
• Sclerokeratitis: An inflammatory condition that affects both the sclera and the cornea.

Other Conditions to Consider:

• Keratoconus: A progressive thinning of the central or paracentral cornea, which can be confused with peripheral degeneration due to similar symptoms.
• Keratoglobus: A rare, non-inflammatory condition characterized by a globular protrusion of the cornea.
• Furrow Degeneration: A type of peripheral corneal thinning that can be confused with Terrien marginal degeneration.

Key Features to Distinguish:

• Inflammation: Peripheral ulcerative keratitis and Mooren ulcer are typically associated with inflammation, whereas Terrien marginal degeneration is not.
• Location: Peripheral degeneration usually affects the peripheral cornea, while keratoconus and keratoglobus affect the central or paracentral cornea.
• Symptoms: Patients with peripheral degeneration may experience decreased visual acuity due to increased corneal astigmatism.

References:

[3] Terrien marginal degeneration may be differentiated from other causes of peripheral corneal thinning by a general lack of inflammation, the presence of superficial vascularization in a radial trajectory, and characteristic histopathologic findings. [11] Thinning conditions such as circumferential peripheral corneal thinning, peripheral ulcerative keratitis, Mooren ulcer, marginal corneal infiltrates, interstitial keratitis associated with infectious disease, neurotrophic ulcus, and sclerokeratitis should be considered in the differential diagnosis of peripheral degeneration. [12] Pellucid marginal corneal degeneration is a bilateral, noninflammatory, peripheral corneal thinning disease that can be distinguished from other conditions by its characteristic physical exam findings.

Note: The above information is based on the search results provided and may not be an exhaustive list of differential diagnoses for peripheral degeneration of the cornea.