Iatrogenic limbal stem cell deficiency following drainage surgery for glaucoma.

OBJECTIVE: To describe conjunctival epithelial overgrowth of the cornea after surgery for glaucoma. METHODS: This is a retrospective case series (setting: Moorfields Eye Hospital). Fourteen eyes of 13 patients with suspected limbal stem cell deficiency (LSCD) and corneal conjunctivalization after glaucoma drainage surgery. Conjunctivalization was defined as corneal epithelium that demonstrated late stain after topical application of fluorescein. Patient demographics, clinical features, potential risk factors, treatment, and final visual acuity were recorded. Main outcome measures were potential risk factors for conjunctivalization, complications, and response to treatment. RESULTS: Eleven eyes had multiple procedures involving the limbus, and in 11 eyes mitomycin C (MMC) or 5 fluorouracil had been used as an adjunct to reduce fibrosis. Affected eyes typically had a segment of late stain with fluorescein based at the site of previous glaucoma surgery, but in one eye there was total loss of the corneal epithelial phenotype. All eyes previously had topical treatment for their glaucoma but only 2 had an ocular surface disease associated with LSCD. Most cases were asymptomatic, but in 3 eyes there was visual loss when the abnormal phenotype crossed the visual axis. In these 3 eyes there was recurrent epithelial breakdown, often at the interface between the 2 epithelial phenotypes. In one individual, these symptoms resolved after limbal epithelial transfer from the unaffected contralateral eye. CONCLUSIONS: Glaucoma drainage surgery can damage the adjacent corneal limbal epithelial stem cell population. This can be associated with recurrent epithelial breakdown and reduced vision. If there is visual loss, limbal epithelial transplantation is a potential treatment option.

Use of an onlay corneal lamellar graft for brittle cornea syndrome.

Brittle cornea syndrome (BCS1 OMIM #229200, BCS2 #614170) is a rare autosomal recessive condition characterised by diffuse thinning and fragility of the cornea. Affected individuals are at risk of globe rupture and blindness after relatively minor eye trauma. We describe a 9-year-old girl with BCS1, already blind in one eye following trauma, who had a 14 mm diameter corneoscleral onlay graft to her contralateral eye to reduce gross irregular corneal astigmatism and potentially to reduce further risk from accidental injury. Although there was a significant initial improvement in the unaided visual acuity, there was subsequent visual loss from secondary glaucoma. In addition, despite the onlay graft, an acute corneal hydrops developed approximately 2 years following surgery, suggesting that in BCS1, corneal tissue degeneration or resorption continues despite external support. Finally, because secondary glaucoma is not a feature of BCS1, we speculate that the onlay graft may have reduced aqueous outflow by compression of the thinned sclera.

Comparison of Short-term Postoperative Hypotony Rates of 23-gauge vs 25-gauge Needles in Formation of the Scleral Tract for Baerveldt Tube Insertion into the Anterior Chamber.

INTRODUCTION: To compare the early postoperative hypotony rates and intraocular pressure (IOP) in two groups of eyes using either 23-gauge (23G) or 25-gauge (25G) needle in the creation of the anterior chamber entry tract for Baerveldt tube. The primary outcome measure was incidence of hypotony, and secondary outcome measures included comparison of mean IOP and other early complications. MATERIALS AND METHODS: Ours was a retrospective case review of consecutive patients who underwent 350 mm2 Baerveldt implantation in two units over a 2-year period. Data including IOP and complications were collected at 1 day, 1 week, and 1 month following surgery from patients' notes. Statistical analysis between groups was determined using the unpaired 2-tailed f-test for continuous variables and chi-squared test for categorical variables. Statistical significance was defined at the 0.05 level. RESULTS: A total of 58 eyes of 58 patients were included in this study. Preoperative mean IOP in the 25G group was significantly higher (26.4 ± 6.8 mm Hg) when compared with the 23G group (21.6 ± 4.0 mm Hg) (p = 0.002). The mean postoperative IOP remained significantly higher in the 25G group at day 1 (p=0.004), week 1 (p = 0.008), but not at month 1 (p = 0.744). Four patients in the 23G group had hypotony within 1 month postsurgery compared with no cases in the 25G group (chi-squared test p = 0.038). CONCLUSION: There was a significantly higher risk of early hypotony and lower IOP in the larger 23G group at days 1 and 7, although the IOP was similar in both groups by 1 month. CLINICAL SIGNIFICANCE: After all glaucoma drainage device (GDD) tube implantation, regardless of which needle is used to create the tract, the entry site should always be checked with 2% fluorescein drop and 10.0 nylon suture is used with or without autologous Tenon's tissue to close any leakage.How to cite this article: Lim KS, Garg A, Cheng J, Muthusamy K, Beltran-Agullo L, Barton K. Comparison of Short-term Postoperative Hypotony Rates of 23-gauge vs 25-gauge Needles in Formation of the Scleral Tract for Baerveldt Tube Insertion into the Anterior Chamber. J Curr Glaucoma Pract 2018;12(1):36-39.