About Limbal Stem Cell Deficiency




Of Limbal Stem Cell Deficiency




LSCD – Limbal Stem Cell Deficiency

Your resource to discover everything about LSCD.

Typical structure of a healthy eye

The diagram below shows the typical structure of a healthy eye.

What are limbal stem cells (LSCs)?

The cornea is the clear layer in front of the eye, and covers the iris (the coloured part of the eye). The corneal epithelium is a surface of tissue that is always regenerating itself, and acts as a barrier to protect the cornea from bacteria.12 The cornea itself does not have a vascular system, as this would interfere with vision.3

The conjunctiva is an opaque thin membrane. It has two parts, one that covers the white part of the eye and one that covers the inner surface of the eyelids.4

The border between the cornea and the white part of the eye is known as the limbus.5 The limbus provides a supply of stem cells to replenish cells in the corneal epithelium. Stem cells get their nutrition from the blood (vascular) system outside the cornea, hence why they must be at the edge of the cornea.6 The limbus prevents vascularisation of the cornea from the conjunctiva. Limbal stem cells (LSCs) are therefore important as they keep the eye healthy and can’t be replaced naturally.7

What happens when you damage
your limbal stem cells (LSCs)?

LSCD occurs when the number of LSCs falls below a critical level.8 When this happens, and the cells can’t repopulate the corneal epithelium, the eye surface can become unstable. The hallmark sign of LSCD is known as ‘conjunctivalisation’, a process in which cells from the conjunctival move into the cornea, covering it with a thin

layer of epithelium containing a network of new blood vessels (‘neovascularisation’).910This produces an unstable surface, prone to tearing, abnormal contraction of eyelid muscles, sensitivity to light (photophobia), reduction or loss of vision, recurrent episodes of pain and persistent inflammation with redness.11

What is limbal stem cell deficiency?

Limbal stem cell deficiency (LSCD) is a condition affecting the eye. It can cause pain, blurred vision, sensitivity to light, and eventually may lead to loss of vision.12

What causes LSCD?

There are numerous causes of LSCD.13 LSCD can be genetic (inherited), or caused by a degenerative disease.
However, it’s more usually caused by a traumatic event, particularly a chemical or heat injury to the eye(s)1415 in a domestic or workplace accident, or a malicious attack. These include injury, trauma from chemical or thermal burns, surgery, radiotherapy or chemotherapy.

Inherited causes 16 17 1819

  • Aniridia

    Missing or incomplete iris

  • Multiple endocrine deficiency

    hormone deficiency that may be associated with inflammation of the cornea

  • Epidermal dysplasia

    Abnormal development of skin cells; it also affects cells within the eye

  • Dyskeratosis congenita

    A disorder that causes bone marrow failure; symptoms also affect the eye

Acquired causes2021

  • Thermal or chemical burns

    The most common cause of LSCD is a thermal or chemical burn to the eye. Approximately 15 000 people (3 in 100 000) in the EU have LSCD caused by burns. Burns cause scarring of the cornea and also destroy limbal stem cells, meaning that the damage cannot be repaired

  • Stevens–Johnson syndrome or chronic limbitis

    Diseases that cause inflammation of the front of the eye may lead to LSCD

  • Long-term contact lens wear

    Irritation from contact lenses or toxicity from the lens solution may damage the limbal stem cells

  • Radiotherapy, cryotherapy or surgery in the limbal area

    Limbal stem cells may be damaged by these therapies. Cryotherapy is a therapy using extreme cold

  • Mitomycin C and 5-fluorouracil

    Medicines applied to the eye may rarely cause LSCD

These lists are adapted from Seipal et al. 19

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