In Vivo Confocal Microscopy of the Corneal-Conjunctival Transition in the Evaluation of Epithelial Renewal after SLET

Diagnostic Algorithm for Surgical Management of Limbal Stem Cell Deficiency

BACKGROUND

Limbal stem cell deficiency (LCSD) presents several challenges. Currently, there is no clearly defined systematic approach to LSCD diagnosis that may guide surgical tactics.

METHODS

The medical records of 34 patients with LSCD were analyzed. Diagnostic modalities included standard (visometry, tonometry, visual field testing, slit-lamp biomicroscopy with corneal fluorescein staining, Schirmer test 1, ultrasonography) and advanced ophthalmic examination methods such as anterior segment optical coherence tomography, in vivo confocal microscopy, impression cytology, and enzyme-linked immunoassay.

RESULTS

Standard ophthalmological examination was sufficient to establish the diagnosis of LSCD in 20 (58.8%) cases, whereas advanced evaluation was needed in 14 (41.2%) cases. Depending on the results, patients with unilateral LSCD were scheduled to undergo glueless simple limbal epithelial transplantation (G-SLET) or simultaneous G-SLET and lamellar keratoplasty. Patients with bilateral LSCD with normal or increased corneal thickness were enrolled in the paralimbal oral mucosa epithelium transplantation (pLOMET) clinical trial.

CONCLUSIONS

Based on the diagnostic and surgical data analyzed, the key points in LSCD diagnosis were identified, helping to guide the surgeon in selecting the appropriate surgical procedure. Finally, we proposed a novel step-by-step diagnostic algorithm and original surgical guidelines for the treatment of patients with LSCD.

Autologous simple conjunctival epithelial transplantation for primary pterygium

PURPOSE

To evaluate the feasibility of a new method of conjunctival transplantation to achieve recovery of the normal conjunctival epithelium over the bare sclera after pterygium excision and prevent its recurrence.

METHODS

After excision of the primary pterygium, we performed simple conjunctival epithelial transplantation (SCET) in which we glued an amniotic membrane patch pre-loaded with tiny autologous conjunctival tissue fragments over the scleral defect. Slit-lamp evaluation was performed at 2 and 7-10 days, and then at 1, 3, 6, and 12 months after surgery, together with confocal microscopy at 3, 6, and 12 months.

RESULTS

Surgical excision and SCET for nasal primary pterygium were performed in 6 eyes (6 patients). No graft detachment occurred. An inflammatory granuloma was excised without sequelae in one patient 2 months after surgery. No signs of recurrence or sight-threatening complications were recorded at 12 months, and in vivo confocal microscopy showed progressive expansion of the conjunctival cell population and formation of a clear corneal-conjunctival transition.

CONCLUSIONS

SCET takes advantage of the ability of the amniotic membrane and conjunctival cells to renew. Outcomes after SCET are comparable to conventional conjunctival flap surgery and can be achieved in less surgical time and with less donor tissue to be removed.

[Simple limbal epithelial transplantation (SLET) : A simple technique for the treatment of unilateral complete limbal stem cell deficiency. Video article]

OBJECTIVE

The aim of simple limbal epithelial transplantation (SLET) is the regeneration of the corneal surface in unilateral complete limbal stem cell deficiency (LSCD).

INDICATIONS

SLET is indicated for unilateral complete LSCD.

CONTRAINDICATIONS

Contraindications include bilateral LSCD, severe corneal thinning, pronounced keratoconjunctivitis sicca, chronic inflammatory condition of the ocular surface, malposition of the eyelids and pronounced adhesions of the conjunctiva with trichiasis.

SURGICAL TECHNIQUE

A 1‑h biopsy is obtained from the superior limbus of the healthy donor eye. A 360° peritomy is performed on the LSCD eye and pannus tissue covering the cornea is removed. An amniotic membrane (AM) is glued to the corneal surface with fibrin. The donor tissue is then divided into 8-10 small pieces, which are placed on the AM sparing the visual axis and fixed by fibrin glue. A contact lens is placed on the eye. A surgical video, which is available online, shows the surgical technique in detail.

FOLLOW-UP

Examinations are necessary within the first postoperative week and 1 month after SLET, then every 3 months within the first postoperative year. Antibiotic eye drops should be applied 5 times daily until complete epithelialization. Topical steroids should be applied 6 times daily in the early postoperative period and can be tapered thereafter. Artificial tears can improve epithelial healing. Ideally, all eye drops should be preservative-free. The contact lens can be removed after 7-10 days. The AM dissolves within a few weeks. An epithelialization of the corneal surface can be observed by the second postoperative week.

EVIDENCE

A recent systematic review reported a stable epithelialized corneal surface in 78% of SLET cases after 1.5 years. An improvement of visual acuity of at least two lines was found in 69% of SLET cases.