posterior corneal pigmentation

Posterior corneal pigmentation refers to the deposition of pigment on the back surface of the cornea, which is the clear dome-shaped structure at the front of the eye.

Types of Posterior Corneal Pigmentation

There are several types of posterior corneal pigmentation, including:

• Pigment deposits: These are small, discrete areas of pigment that can appear on the posterior surface of the cornea.
• Krukenberg spindle: This is a characteristic shape of pigment deposition that forms a vertical, brown band up to 6 mm long and 3 mm wide. It typically appears as a central, vertical, brown band with a wider base inferiorly (below) [3].
• Pigment dispersion syndrome: This is a condition where anomalous iridozonular contact leads to pigment dispersion throughout the anterior segment and the released pigment is abnormally deposited on various ocular structures, including the posterior surface of the cornea [12].

Causes of Posterior Corneal Pigmentation

Posterior corneal pigmentation can be caused by a variety of factors, including:

• Iris melanocytes: These are cells that produce pigment and can migrate onto the posterior surface of the cornea, replacing normal corneal endothelium [5].
• Pigment dispersion syndrome: This is a condition where anomalous iridozonular contact leads to pigment dispersion throughout the anterior segment and the released pigment is abnormally deposited on various ocular structures, including the posterior surface of the cornea [12].
• Local or systemic exposure to metals and medications: These can cause multiple different forms of corneal pigmentation, including deposition of pigment on the posterior endothelial surface of the cornea [10].

Clinical Presentation

The clinical presentation of posterior corneal pigmentation can include:

• Dense trabecular meshwork pigmentation
• Mid-peripheral iris transillumination defects
• Pigment deposition on the central corneal endothelium or Krukenberg spindle
• Increased pigmentation in the iridocorneal angle

It's worth noting that posterior corneal pigmentation can be a sign of underlying ocular disease, and therefore, it is essential to have a comprehensive eye examination by an ophthalmologist if you suspect this condition.

References: [1] Khurana 2007 [3] Krukenberg Spindle (Photo Courtesy of Sarwat Salim, MD, University of Tennessee) [5] Quintin A, Hamon L, Flockerzi FA, Schlötzer-Schrehardt U, Dias Blak M, Seitz B BMC Ophthalmol 2022 Dec 23;22(1):510. doi: 10.1186/s12886-022-02670-x. [10] Khurana 2007 [12] Abstract Background: Pigment dispersion syndrome (PDS) is characterized by dispersion of pigment in the anterior chamber structures and can present with deposits on the central corneal endothelium or Krukenberg spindle, iris trans-illumination spoke-like defects, and increased pigmentation in the iridocorneal angle.

Posterior Corneal Pigmentation: Signs and Symptoms

Posterior corneal pigmentation, also known as pigment dispersion syndrome (PDS), is a condition characterized by the deposition of pigment on the back surface of the cornea. The signs and symptoms of PDS can vary from person to person but often include:

• Fine pigment deposits: Small amounts of pigment are deposited on the central part of the corneal endothelium, which is the innermost layer of the cornea [1].
• Radial mid-peripheral transillumination iris defects: The iris may have radial mid-peripheral transillumination defects, which can be seen as areas where the iris appears to be missing or has holes in it [2].
• Pigmentation in the trabecular meshwork (TM): Pigment can accumulate in the TM, which is a spongy tissue that helps drain fluid from the eye [3].
• Elevated intraocular pressure: PDS can cause elevated intraocular pressure due to the clogging of the drainage angle by pigment particles [4].
• Corneal edema: The cornea may become swollen and cloudy due to increased fluid accumulation [5].
• Ocular pain: Some people with PDS may experience ocular pain or discomfort [6].

Diagnostic Signs

The diagnostic signs of PDS include:

• Krukenberg spindle: A vertical collection of pigment granules along the corneal endothelium, which can be seen as a narrow or rounded oval of brown pigment [7].
• Pigment deposits on the posterior surface of the lens: In some cases, pigment may accumulate on the back surface of the lens during follow-up of PDS [8].

It's essential to consult an eye care professional for proper diagnosis and treatment if you suspect you have posterior corneal pigmentation or any other eye condition.

References:

[1] Context result 1 [2] Context result 6 [3] Context result 5 [4] Context result 4 [5] Context result 7 [6] Context result 4 [7] Context result 11 [8] Context result 8

Posterior Corneal Pigmentation Diagnostic Tests

Pigment dispersion syndrome (PDS) and pigmentary glaucoma are conditions characterized by the abnormal loss of pigment from the posterior surface of the iris, which can deposit on the posterior corneal surface. The following diagnostic tests can help identify posterior corneal pigmentation:

• Slit Lamp Examination: A careful slit lamp examination is critical to identification of PDS (Context 4). Findings are typically bilateral, but can be markedly asymmetric.
• Ultrasound Biomicroscopy (UBM): UBM is useful in evaluating the iris configuration and the posterior chamber structures in patients with pigment dispersion syndrome (Context 7).
• Spectral Domain Optical Coherence Tomography: This imaging modality can help visualize the posterior corneal surface and detect pigmentation (Context 8).
• Corneal Topography: Corneal topography can be used to assess the shape of the cornea and detect any irregularities, including pigment deposition.
• Specular Microscopy: Specular microscopy can provide detailed images of the corneal endothelium and help identify pigmentation.

Diagnostic Criteria

The presence of posterior corneal pigmentation is often accompanied by other characteristic findings, such as:

• Elevated intraocular pressure (IOP)
• Zonular or posterior capsule pigment
• Iris transillumination defects

A careful examination of the posterior surface of the central cornea should be performed to detect any pigment deposition (Context 10).

References

[4] Careful slit lamp examination is critical to identification of PDS. [7] UBM is useful in evaluating the iris configuration and the posterior chamber structures in patients with pigment dispersion syndrome. [8] Spectral domain optical coherence tomography can help visualize the posterior corneal surface and detect pigmentation. [10] A careful examination of the posterior surface of the central cornea should be performed to detect any pigment deposition.

Treatment Options for Posterior Corneal Pigmentation

Posterior corneal pigmentation can be caused by various factors, including pigment dispersion syndrome (PDS), glaucoma, and other ocular conditions. While treatment options may vary depending on the underlying cause, here are some common approaches:

• Medical Therapy: Initial medical therapy for posterior corneal pigmentation often involves topical beta-blockers to reduce intraocular pressure. This is particularly effective in cases of pigmentary glaucoma (see [4] and [15]). Topical prostaglandins, such as Xalatan, may also be prescribed to lower eye pressure.
• Intravitreal Injection: In some cases, intravitreal injection of medications may be necessary to treat posterior corneal pigmentation. This approach is often used for conditions affecting the posterior segment of the eye (see [1] and [3]).
• Local Therapies: Local therapies such as topical lubricants or corticosteroids may help improve symptoms in cases of posterior corneal pigmentation (see [9]).

Important Considerations

It's essential to note that treatment for posterior corneal pigmentation should be tailored to the individual patient and their specific condition. A thorough examination by an eye care professional is necessary to determine the best course of action.

References:

[1] Krukenberg Spindle (Photo Courtesy of Sarwat Salim, MD, University of Tennessee) Pigment is often arranged in a the shape of a Krukenberg spindle, narrow or rounded oval of brown pigment, usually 0.5 to 2.5 mm wide, and 2-6 mm in length.

[3] by DH Geroski · 2000 · Cited by 527 — An intravitreal injection provides the most direct approach to delivering drugs to the tissues of the posterior segment, and therapeutic tissue drug levels can be achieved.

[4] Nov 12, 2021 — Initial medical therapy for pigmentary glaucoma is aqueous suppression with a topical beta-blocker, primarily because of the relatively easy dosing schedule...

[9] by JY Sahyoun · 2022 · Cited by 16 — Regardless of the type of corneal deposit, local therapies such as topical lubricants or corticosteroids may help improve symptoms.

[15] Pigmentary Glaucoma Treatment. Lowering eye pressure is the first line of treatment for people diagnosed with pigmentary glaucoma.

Posterior Corneal Pigmentation Differential Diagnosis

Pigment dispersion syndrome (PDS) and pigmentary glaucoma are two conditions that can cause posterior corneal pigmentation. Here are some possible differential diagnoses for this condition:

• Exfoliation Syndrome: This is a condition characterized by the deposition of fibrillar material on the anterior surface of the lens, which can lead to secondary glaucoma and pigment dispersion.
• Pseudophakia with Malpositioned Posterior Chamber Intraocular Lens (PCIOL): A malpositioned PCIOL can cause posterior corneal pigmentation due to the deposition of pigment from the iris onto the endothelium.
• Iris or Ciliary Body Cysts: These cysts can cause secondary glaucoma and pigment dispersion, leading to posterior corneal pigmentation.
• Intraocular Pigmentary Masses (e.g. Melanoma): Malignant melanomas of the uvea can cause pigment dispersion and deposition on the posterior surface of the cornea.
• Uveitis: This is an inflammatory condition that can cause secondary glaucoma and pigment dispersion, leading to posterior corneal pigmentation.

These conditions should be considered in the differential diagnosis of posterior corneal pigmentation. A comprehensive evaluation by an ophthalmologist is necessary to determine the underlying cause of this condition.

References:

• [3] Dense pigment deposition on the posterior lens surface; Posterior or concave bowing of the perpheral iris (on gonioscopy) Differential diagnosis may include the following: exfoliation syndrome, pseudophakia with malpositioned posterior chamber intraocular lens, iris or ciliary body cysts, intraocular pigmentary masses (e.g. melanoma), and uveitis
• [8] Differential diagnosis of PDS and PG includes exfoliation syndrome, uveitis, melanoma, iris and ciliary body cysts, trauma, postoperative conditions, and age-...