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Band Shaped Keratopathy (BSK)





It is a corneal degeneration characterised by the deposition of calcium hydroxyapatite in the epithelial basement membrane, Bowman’s membrane and anterior stroma.

It typically begins just inside the limbus in the periphery. There is a sharply demarcated edge separated from the limbus by a lucent zone.


Why does the lucent zone occur?

  1. The absence of the Bowman's layer in the extreme periphery of the cornea.

  2. Due to the buffering capacity of limbal vessels, which prevent deposition of calcium.

It is initially grey but becomes chalky-white as it progresses. It spreads centrally in a "band-like" distribution and affects the visual axis. The deposits may extend anteriorly and break through the epithelium leading to symptoms such as irritation and foreign body sensation.

In advanced cases (second picture), there is a “Swiss cheese" appearance due to the lucent holes in the calcific pattern caused by corneal nerve penetration through Bowman's layer.


Causes:

  • Uveitis (Especially Juvenile Idiopathic Arthritis)

  • Herpetic keratouveitis (especially herpes zoster)

  • Chronic glaucoma

  • Dry eye and exposure conditions

  • Interstitial keratitis

  • Phthisis bulbi

  • Chemical exposure: mercury fumes, phosphate containing drops, intraocular silicone etc

  • Hypercalcemia - all causes of it

  • Hereditary disorders: Norrie's disease and congenital band keratopathy

  • Systemic diseases: discoid lupus, gout etc


In patients who are symptomatic or have visual disturbances, superficial keratectomy can be done- manually with or without chelating agent such as EDTA, or with excimer laser phototherapeutic keratectomy.


Image from Rajan Eye Care Hospital

#ophthalmology #ophthal #cornea

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Blue dot cataract/ cataracta punctata caerulea was first described by Vogt- it is not a true congenital cataract but is a form of developmental cataract ⁣

Autosomal dominant inheritance- genes located on 17q and 22q⁣

Characteristic discrete punctate opacities (round bluish dots) situated in the peripheral part of adolescent nucleus and deeper layers of cortex forming a concentric layer with central ones radially oriented ⁣

Stationary, non-progressive opacities which are not visually significant and hence do not necessitate surgical intervention. 





Image from Rajan Eye Care Hospital 

#ophthalmology #ophthal #lens #bluedotcataract #cataract 

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Keratoconus is a non - inflammatory, progressive condition where the central or paracentral cornea undergoes progressive thinning and steepening causing irregular astigmatism and a ‘cone shaped’ cornea. ⁣

𝐄𝐱𝐭𝐞𝐫𝐧𝐚𝐥 𝐬𝐢𝐠𝐧𝐬 𝐨𝐟 𝐊𝐞𝐫𝐚𝐭𝐨𝐜𝐨𝐧𝐮𝐬 ⁣⁣

⁣⁣⁣

𝐌𝐮𝐧𝐬𝐨𝐧’𝐬 𝐒𝐢𝐠𝐧⁣⁣⁣

V shaped conformation of lower lid produced by the ectatic cornea in downgaze ⁣⁣⁣

⁣⁣⁣

𝐑𝐢𝐳𝐮𝐭𝐭𝐢’𝐬 𝐒𝐢𝐠𝐧⁣⁣⁣

Sharply focused beam of light near the nasal limbus produced by lateral illumination of the cornea ⁣⁣⁣




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Other external signs : ⁣⁣⁣

Charleux sign: Dark reflex in centre of cornea with distant direct ophthalmoscope in dilated pupils ⁣⁣⁣

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Scissoring reflex on retinoscopy ⁣⁣⁣

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Image from Rajan Eye Care Hospital⁣⁣

#ophthalmology #ophthal #cornea #keratoconus

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