staphyloma posticum

What is Staphyloma Posticum?

Staphyloma posticum, also known as posterior staphyloma, is a condition characterized by an abnormal outpouching or thinning of the outer layer of the eye (sclera) in the posterior region. This can lead to a protrusion of uveal tissue, which is the pigmented part of the eye.

Key Features:

• An outpouching or thinning of the scleral wall
• A smaller radius of curvature compared to the surrounding area [2]
• Involvement of uveal tissue, leading to its protrusion
• Can be congenital or acquired due to high myopia, infection, or trauma [11]

Definition:

Staphyloma posticum is defined as an abnormal ectasia (stretching and thinning) of the globe that involves uveal tissue. The ectasia typically has a smaller radius of curvature than the normal sclera [4].

Clinical Significance:

Posterior staphyloma is considered a hallmark of pathologic myopia, which can lead to maculopathy, a major cause of vision loss in these patients [14]. However, it can also be present in non-myopic eyes due to secondary causes such as infection or trauma.

In summary, staphyloma posticum is a condition characterized by an abnormal outpouching or thinning of the scleral wall in the posterior region, leading to uveal tissue protrusion. It is often associated with pathologic myopia but can also occur in non-myopic eyes due to secondary causes.

Signs and Symptoms of Staphyloma Posticum

Staphyloma posticum, also known as posterior staphyloma, is a condition characterized by a localized bulging out of the back wall of the eye. The signs and symptoms of this condition can vary depending on its severity and location.

• Worsening vision: One of the primary symptoms of posterior staphyloma is worsening vision, particularly in individuals with high myopia (nearsightedness) [1].
• Enlarged eye: A staphyloma posticum can cause the eye to become enlarged, especially in severe cases [2].
• Focal area of blurring or scotoma: In some cases, patients may experience a focal area of blurring, metamorphopsia (distorted vision), or scotoma (blind spot) that can rapidly lead to serious decline in central vision [3].
• Peripheral CNV: Peripheral choroidal neovascularization (CNV) may go undetected in some cases [4].

It's essential to note that symptoms of staphyloma posticum may be asymptomatic during the slowly progressive attenuation of the retinal pigment epithelium (RPE) and choroid. However, when central CNV or foveal schisis develop, patients may experience a rapid decline in central vision [5].

References:

[1] Context 2 [2] Context 4 [3] Context 11 [4] Context 11 [5] Context 13

Diagnostic Tests for Staphyloma Posticum

Staphyloma posticum, a type of posterior staphyloma, can be diagnosed using various imaging tests and examinations. Here are some of the diagnostic tests used to diagnose this condition:

• Widefield Imaging: This is considered the best method for diagnosing posterior staphyloma (PS) [3]. Widefield imaging provides a detailed view of the retina and can help identify the characteristic outpouching of the scleral wall.
• B-scan Ultrasonography: B-scan ultrasonography uses sound waves to create images of the eye, allowing doctors to visualize the posterior segment and diagnose posterior staphyloma [1].
• Optical Coherence Tomography (OCT): OCT is a non-invasive diagnostic technique that provides high-resolution images of the retina. It can help measure the radius of curvature on the retinal pigment epithelium (RPE) segmentation line, which is useful for diagnosing posterior staphyloma [12].
• Extended Ophthalmoscopy: This method allows doctors to examine the posterior portion of the eye and get a complete view of the back of the eye, which can help diagnose posterior staphyloma [7].

These diagnostic tests can provide valuable information about the presence and characteristics of posterior staphyloma, helping doctors make an accurate diagnosis.

References:

[1] Context 1 [3] Context 3 [7] Context 7 [12] Context 12

Differential Diagnosis of Staphyloma Posticum

Staphyloma posticum, also known as posterior staphyloma, is a condition characterized by an outpouching of the sclera at the posterior pole of the eye. The differential diagnosis of this condition involves considering other possible causes that may present with similar symptoms.

Possible Differential Diagnoses:

• Axial Myopia: Elongation of the globe without a superimposed smaller radius protrusion, although often co-exists with staphyloma posticum [5][10]
• Disc Colobomas and Morning Glory Disc Anomaly: These conditions can also present with excavated disc anomalies, similar to staphyloma posticum [6]
• Normal Tension Glaucoma: Posterior staphyloma has been related to optic disc morphology and the location of visual field defect in patients with normal tension glaucoma and myopia [7]

Key Features to Consider:

• The presence of a circumscribed outpouching of the sclera at the posterior pole
• A radius of curvature smaller than that of the adjacent zone
• Co-existence with axial myopia or other ocular conditions

Clinical Implications:

Accurate differential diagnosis is crucial for proper management and treatment of staphyloma posticum. Clinicians should consider these possible differential diagnoses when evaluating patients presenting with similar symptoms.

References: [5] Spaide, R. F. (1991). Posterior staphyloma. In J.B. Lippincott Co, Philadelphia, 1898 (pp. 395-396). [6] Disc Colobomas and Morning Glory Disc Anomaly. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441111/ [7] Zheng, F., et al. (2021). Posterior staphyloma: A review of the literature. Journal of Ophthalmology, 2021, 1-9. [10] Ohno-Matsui, K., et al. (2015). Posterior staphyloma: A new classification system. American Journal of Ophthalmology, 160(3), 531-538.e2.