obsolete peripheral anterior synechiae

Peripheral Anterior Synechiae (PAS): A Brief Overview

Peripheral anterior synechiae (PAS) refer to adhesions that form between the iris and the trabecular meshwork in the iridocorneal angle. These adhesions can alter the anatomy of the anterior chamber, potentially impeding aqueous outflow and contributing to increased intraocular pressure.

Characteristics of Obsolete PAS

Obsolete design of PAS refers to the remnants or scars left behind after the initial formation of these adhesions. According to a study by D Davis in 2010 [1][2], long-term pathological follow-up of obsolete design PAS showed that they can persist even after the initial adhesion has resolved.

Effects on the Anterior Chamber

The presence of obsolete PAS can still affect the anterior chamber, causing mild to moderate peripheral anterior synechiae to persist on gonioscopy. Despite this, the angle may remain sufficiently patent to allow adequate trabecular meshwork function [3].

Association with Glaucoma and Other Conditions

PAS are often associated with glaucoma, particularly primary angle-closure glaucoma (PACG). They can also develop in other ocular conditions such as uveitis and iris neovascularization. In some cases, PAS may be seen within a week after shallow to flat anterior chamber [4].

Importance of Identifying PAS

Identifying PAS is crucial for classifying the stage of primary angle-closure disease (PACD) and understanding its progression. The presence of PAS can also indicate the need for further evaluation and management of associated conditions.

References:

[1] D Davis, 2010 - Long-term pathological follow-up of obsolete design peripheral anterior synechiae [2] [3] Context result 4 [4] Context result 14

Symptoms and Signs of Peripheral Anterior Synechiae (PAS)

Peripheral anterior synechiae (PAS) is a condition where the iris adheres to the trabecular meshwork or the cornea, leading to complications such as glaucoma, cataract development, and reduced vision. The symptoms and signs of PAS can vary depending on the severity and extent of the adhesion.

• Circumlimbal injection: This is a common presenting sign of acute anterior uveitis, which can be associated with PAS [3].
• Anterior chamber cells and flare: These are indicative of inflammation in the anterior segment, which can be seen in cases of PAS [2].
• Reduced vision: As the iris adheres to the trabecular meshwork or cornea, it can lead to reduced vision due to cataract development or glaucoma [4].
• Glaucoma: This is a complication of PAS, where increased intraocular pressure can lead to damage to the optic nerve and loss of vision [6].
• Cataract development: The adhesion of the iris to the trabecular meshwork or cornea can also lead to cataract development, which can further reduce vision [4].

Complications of PAS

If the peripheral anterior synechiae occupy less than 50% of the circumference, iridectomy or iridotomy may suffice. However, if the adhesion is more extensive, it can lead to complications such as:

• Band keratopathy: This is a complication where calcium deposits form on the cornea [6].
• Posterior synechiae: This is another type of adhesion that can occur between the iris and the lens [6].

It's worth noting that the symptoms and signs of PAS can be non-specific, making it challenging to diagnose. A comprehensive eye examination by an ophthalmologist is essential for accurate diagnosis and treatment.

References: [1] Not applicable [2] Context 2 [3] Context 3 [4] Context 4 [5] Not applicable [6] Context 6

Diagnostic Tests for Obsolete Peripheral Anterior Synechiae

Peripheral anterior synechiae (PAS) are a condition where the iris adheres to the trabecular meshwork, potentially leading to glaucoma. Diagnostic tests can help identify PAS and assess its severity.

• Gonioscopy: This is a critical diagnostic test for evaluating the extent of tumor involvement in eyes with malignancies of the anterior segment (Source: [5]). Gonioscopy allows for direct visualization of the angle between the iris and cornea, enabling detection of peripheral anterior synechiae, neovascularization of the angle, and the presence of an open or closed angle (Source: [8]).
• B-scan ultrasonography: This test permits two-dimensional visualization of the anterior and posterior segment when a direct view with the biomicroscope is not possible (Source: [2]). While it may not directly diagnose PAS, it can provide valuable information on the anatomy of the eye.
• Indentation gonioscopy: This technique involves gently pressing on the cornea to widen the angle and allow for better visualization. It can help confirm permanent synechial closure of any extent in chronic angle-closure glaucoma (Source: [9]).

These diagnostic tests are essential for identifying obsolete peripheral anterior synechiae and assessing their impact on eye health. Early detection and treatment can prevent further complications, such as glaucoma.

References: [2] - Source 2 [5] - Source 5 [8] - Source 8 [9] - Source 9

Based on the provided context, it appears that there are various treatment options for peripheral anterior synechiae (PAS), but the focus here is on drug treatment.

According to search result [12], anti-glaucoma medications can be used as a treatment modality for patients with documented acute or subacute angle-closure glaucoma attack, persistent increase IOP and PAS without underlying secondary causes. However, it does not specifically mention obsolete PAS.

But, in the context of treating PAS, corticosteroids are mentioned in search result [1] and [2] as a treatment option for inflammation, which might be relevant to treating PAS-related complications.

It's worth noting that the primary focus of treatment for PAS is usually surgical intervention or laser treatments, rather than drug treatment. However, based on the provided context, it seems that anti-glaucoma medications and corticosteroids might have some role in managing symptoms or complications related to PAS.

Here are some possible treatment options:

• Anti-glaucoma medications: These can be used to manage increased intraocular pressure associated with PAS.
• Corticosteroids: These can be used to reduce inflammation, which may be a contributing factor to PAS-related complications.
• Other treatments mentioned in the context include laser iridoplasty, anterior chamber paracentesis, surgical iridectomy, synechialysis, and cataract extraction.

Please note that these are general suggestions based on the provided context, and specific treatment plans should be tailored to individual patient needs and circumstances.

Peripheral anterior synechiae (PAS) are adhesions of the peripheral iris to the angular structures of the anterior chamber, which can be observed in various conditions. However, when PAS is considered obsolete, it's essential to consider differential diagnoses that may mimic or be related to this condition.

Based on the search results, the following conditions can be considered as differential diagnoses for obsolete peripheral anterior synechiae:

• Re-closure of the Laser Peripheral Iridotomy (LPI): This is a possible cause of PAS recurrence, which can lead to the reappearance of symptoms associated with PAS. [8][10]
• Persistent peripheral iris adhesion: Even after treatment, some patients may experience persistent adhesions between the iris and the angle, leading to similar symptoms as PAS. [13]
• Iris neovascularization: This condition involves the growth of new blood vessels on the surface of the iris, which can cause adhesions and lead to symptoms similar to PAS. [15]
• Uveitis: Inflammation within the uveal tract (iris, ciliary body, and choroid) can cause adhesions between the iris and the angle, leading to symptoms similar to PAS. [3][15]
• Posterior synechiae: This condition involves adhesions between the iris and the lens or posterior parts of the eye, which can be mistaken for PAS due to similar symptoms. [12]

It's essential to note that these conditions may require different treatment approaches and should be ruled out before considering obsolete peripheral anterior synechiae as a diagnosis.

References:

[3] - The pupil may be irregular, and the cornea presents with endothelial changes related to peripheral anterior synechiae. [8] - Laser peripheral iridotomy (LPI) is indicated to prevent or overcome a suspected relative pupillary block by creating an alternative pathway for aqueous flow. [10] - In 1938, Barkan described peripheral anterior synechiae (PAS) between the peripheral iris and trabecular meshwork (TM), which could lead to increased intraocular pressure (IOP). [12] - Posterior synechia: it pertains to the binding of the iris with the lens or the back parts of the eye ... [13] - Peripheral anterior synechia (PAS) is a condition in which the iris adheres to the angle, and it is one of the pathognomonic signs of primary angle-closure glaucoma (PACG). [15] - Peripheral anterior synechiae (PAS) are adhesions of the peripheral iris to the angular structures of the anterior chamber and can be observed in a variety of conditions including uveitis, neovascular glaucoma, iridocorneal endothelial syndrome and following ocular trauma or surgeries.