Biomedical Engineering Reference
In-Depth Information
presence of conjunctival epithelial cells in the sample by staining for goblet cell
mucins or for conjunctival specific cytokeratins. If present, this confirms corneal
surface conjunctivalisation and therefore, LESC deficiency.
Other tools being investigated for diagnosis of LESC deficiency include
imaging modalities such as in vivo confocal microscopy and high resolution
optical coherence tomography [
34
]. At present, however, these are not routinely
used to diagnose LESC deficiency in the clinic.
3.9 The Management of Limbal Stem Cell Deficiency
The management of LESC deficiency can often be difficult and complex. The
management options depend very much upon the extent of the disease and whether
or not one or both eyes of the patient are affected [
29
]. LESC deficiency can be
described as partial or total depending upon the extent of the limbal barrier
broached and the amount of the corneal surface conjunctivalised. Unilateral LESC
deficiency, where one eye remains normal, first means that the patient still has one
seeing eye and second that the healthy eye can be used as a source of limbal tissue
for any surgical options which may be considered.
Conservative management is often employed for the treatment of LESC defi-
ciency. This includes the use of topical agents such as lubricants, anti-inflamma-
tories, antibiotics and autologous serum. Bandage contact lenses can also be used
to stabilise the ocular surface and promote epithelial healing.
Partial LESC deficiency is managed depending upon whether the patient is
symptomatic from the disease. If the visual axis is not affected and the corneal
surface is stable, conservative management or even simple observation may be
employed. If the disease is progressive and the visual axis is affected or threatened,
then surgical options may need to be employed. These include removing the
encroaching conjunctival epithelium up to the limbus and allowing the limbal
barrier to be restored [
35
]. This can be performed with or without amniotic
membrane transplantation. Human amniotic membrane is often transplanted to the
surface of the eye as it has a stabilising effect on the epithelium by providing an
extracellular matrix scaffold, anti-inflammatory effects and anti-angiogenic prop-
erties [
36
]. In addition, amniotic membrane is relatively immune privileged and
the recipient does not require immune suppression.
Total LESC deficiency requires the replacement of healthy limbal tissue. This
can be in the form of whole tissue limbal grafts or cultured limbal epithelial grafts
[
37
-
42
] (Fig.
3.1
i). Corneal transplantation is not a primary treatment modality for
LESC deficiency. Replacement of the central cornea means that when the corneal
epithelium is shed from the grafted cornea, the LESC deficient host cannot replace
the epithelium on the graft. The graft then either becomes conjunctivalised or is
rejected. In LESC deficiency, corneal epithelial regeneration has to be normalised
in the first instance. If despite this, the cornea remains hazy, for example as a result
