Cultivated limbal stem cell transplantation Figure 2 Slit lamp photo showing causes of limbal stem cell deﬁciency (LSCD). A: Corneal pannus due to vernal keratoconjunctivitis (VKC). B: Dysfunction of limbal stem cell in a patient with VKC. C: Total stem cell deﬁciency with conjunctivalisation and multiple symblephara in a patient with chemical injury. D: Peripheral corneal destruction due to Mooren’s ulcer which leads to limbal stem cell deﬁciency over a period of time. they occupy the ocular surface is eventually keratinised, which sometimes may be seen at the end stage of OCP or SJS (Coster et al 1995). Corneal stem cell deficiency can be best confirmed histologically by the use of impression cytology, which can detect goblet cells containing conjunctival epithelium on the corneal surface (Sangwan 2001). Immunohisto-chemi- cally, the absence of keratin CK3, and the presence of mucin in goblet cells, has been shown by monoclonal antibodies (Kenyon et al 1990). Diagnosis of limbal stem cell deﬁciency is crucial because patients with this abnormality generally are poor candidates for conventional corneal transplantation. Lamellar or penetrating keratoplasty provides only a tempo- rary replacement of the host’s corneal epithelium because the grafted epithelial cells have a limited proliferative capacity and lifespan (Dua et al 2000). Management of LSCD Asymptomatic patients with partial and peripheral conjuncti- valisation of the corneal surface may not require intervention. Corneal and conjunctival epithelial cell phenotypes have been known to co-exist on the corneal surface for prolonged periods without signiﬁcant extension of the conjunctivalised area or any transdifferentiation of conjunctival epithelium Clinical Ophthalmology 2008:2(3) into cells of corneal phenotype (Coster et al 1995; Dua 1995). If the visual axis or most of the corneal surface is covered with conjunctiva-like epithelium, mechanical debridement of conjunctival epithelium can allow adequate corneal epithelial healing to occur from the remaining intact limbal epithelium (Coster et al 1995; Dua 1995). Scraping is done with a surgical blade under topical anesthesia at the slit lamp. Any tendency of conjunctiva-like epithelium to re-encroach on to corneal surface is prevented by re-scraping (Coster et al 1995). This procedure can be employed to improve visual function and reduce symptoms even when as little as two clock hours of normal limbus and peripheral cornea remain. When visual improvement is the aim of treatment, the objective should be to achieve normal corneal epithelial cover over the visual axis. An attempt to achieve normal epithelial cover for the entire cornea, when only two clock hours or less of limbus are surviving, may stretch the capac- ity of the remaining limbus and could eventually lead to epithelial breakdown. Mechanical debridement of conjunctiva-like epithelium and encouraging the denuded area to be resurfaced with cor- neal epithelial cells is a valid, simple and effective alternative to limbal transplantation in patients with partial limbal stem cell deﬁciency (see below). 491