Cross-linked actin networks (CLANs) are present in lamina cribrosa cells.

AIMS: A study was undertaken to determine and compare the F-actin staining patterns in the cells of the lamina cribrosa (LC) of normal, dexamethasone (DEX)-treated and glaucomatous dissected tissue and cell cultures. METHODS: About 30 dissected donor eyes and nine cell lines provided the human specimens; 25 eyes and 20 primary cell cultures provided the bovine material. Appropriate samples were exposed to 1×10⁻7 M DEX for up to 14 days. LC tissue and cells were stained with Phalloidin-Alexa 488 to identify F-actin, and all samples were examined by confocal or epifluorescent microscopy. RESULTS: Both in the LC tissue and LC cell cultures the dominant actin arrangement was bundles of stress fibres. However, cross-linked actin networks (CLANs) were identified in the tissue and in culture. These were markedly increased by steroid treatment and were particularly large and abundant in cultures from glaucoma donors. CLANs were not associated with optic nerve head astrocytes. CONCLUSIONS: The presence of abundant stress fibres in situ and in vitro highlights the biomechanical contribution of LC cells. However, the identification of CLANs in these cells shows that they are not exclusive to the trabecular meshwork, the only other place they have been found, and may have a role in glaucoma pathology.

Periorbital necrotising fasciitis: delay in diagnosis results in loss of lower eyelid.

Necrotising fasciitis (NF) is an extremely rare skin and soft tissue infection with extensive necrosis of the subcutaneous tissue and underlying fascia, which usually affects the limbs and trunk. It rarely affects the head and neck region because of the excellent blood supply in this region. We report a case of NF initially misdiagnosed as a traumatic pre-septal cellulitis following self-puncture of a hordeolum externum (stye) and its resistance to aggressive antibiotic therapy resulting in the loss of the lower eyelid.