What causes opacities or deposits in the pupils?

Causes of Opacities or Deposits in Pupils

Opacities or deposits visible in the pupillary area are most commonly lens opacities (cataracts), particularly posterior subcapsular cataracts, which can appear as deposits when viewed through the dilated pupil, though the question likely refers to deposits on the lens capsule or crystalline lens itself rather than true pupillary deposits.

Primary Causes of Lens Opacities Visible Through the Pupil

Fabry Disease - Characteristic Lens Deposits

• Fabry disease produces a unique pattern of branching opacities (dendritic opacities) lying just inside the posterior lens capsule 1
• These dendritic opacities do not impair visual acuity and are best visualized after pupil dilation, viewing the posterior lens capsule in the reflected red light of the fundus with a slit-lamp biomicroscope 1
• These deposits do not represent an indication for cataract extraction 1
• Fabry disease is a metabolic/hereditary condition that should be considered when bilateral characteristic lens deposits are present 1

Cataracts and Posterior Capsule Opacification

• Posterior capsule opacification following cataract surgery results from proliferation of anterior lens epithelium onto the posterior capsule, creating frank opacities through multiple layers of proliferated epithelium 2
• Myofibroblastic differentiation of lens cells causes contraction producing tiny wrinkles in the posterior capsule, resulting in visual distortion 2
• In uveitis patients, posterior capsule opacification occurs at higher rates, with estimates of 38.5% at 1 year and 56% at 3 years post-surgery 3

Uveitis-Related Deposits

• Intraocular lens deposits can occur as a complication in uveitis patients following cataract surgery 4
• Inflammatory deposits may accumulate on the lens capsule or intraocular lens surface in patients with chronic intraocular inflammation 4
• Keratic precipitates on the corneal endothelium may be visible through the pupil in cases of anterior uveitis 1

Medication-Induced Opacities

Systemic Medications Causing Corneal/Lens Changes

• Amiodarone causes corneal opacification that may be visible through the pupil 1
• Rho kinase inhibitors can cause verticillate changes (cornea verticillata pattern) 1
• Various chemotherapeutic agents may cause corneal opacification 1
• Dietary calcium supplementation has been associated with corneal opacification 1

Metabolic and Hereditary Causes

Storage Diseases

• Mucopolysaccharidosis causes corneal opacification that may be partially reversible with treatment 1
• Cystinosis produces cysteine crystal deposits that may resolve with treatment 1
• These metabolic deposits typically affect the cornea but may be visible through the pupillary aperture 1

Congenital Causes

Developmental Anomalies

• Congenital corneal opacities may be classified as primary (corneal dystrophies, choristomas) or secondary (kerato-irido-lenticular dysgenesis) 5
• Peters' anomaly represents developmental anomalies affecting the anterior segment that may present with opacities visible through the pupil 5
• These conditions necessitate anterior segment imaging (OCT or high-frequency ultrasound) or histology for proper classification 5

Clinical Approach and Pitfalls

Key Diagnostic Considerations

• Distinguish between corneal opacities, lens opacities, and true pupillary deposits through careful slit-lamp examination using various illumination techniques (sclerotic scatter, specular reflection, indirect illumination) 1
• Pupil dilation is essential for visualizing posterior lens capsule deposits and posterior subcapsular cataracts 1
• Consider systemic diseases, particularly Fabry disease when characteristic dendritic posterior lens opacities are present 1

Important Caveats

• Visual acuity may not correlate with the degree of opacity visible on examination 1
• Younger patients are at higher risk for posterior capsule opacification following cataract surgery 3, 6
• History of uveitis significantly increases risk of lens deposits and posterior capsule opacification, with earlier onset of visually significant changes 3, 6
• Hydrophilic intraocular lenses are associated with higher rates of posterior capsule opacification compared to hydrophobic lenses 6