Expression and localisation of BDNF, NT4 and TrkB in proliferative vitreoretinopathy.

Exogenous brain derived neurotrophic factor (BDNF) is known to rescue ganglion cell death after optic nerve injury. Its mechanism of action is believed to be indirect via glial cells in the retina. In this study we investigated the changes in expression and localisation of BDNF, neurotrophin-4 (NT4) and their common receptor (TrkB) in retinectomy sections of patients with proliferative vitreoretinopathy (PVR). Nine full-thickness retinectomy specimens obtained at retinal reattachment surgery for PVR were fixed in 4% paraformaldehyde immediately after excision and compared to similarly processed normal donor retinas (4 eyes). Agarose-embedded sections (100 microm thick) were double labelled for immunohistochemistry by confocal microscopy, with antibodies against BDNF, NT4, TrkB, rod opsin, glial fibrillary acidic protein (GFAP), cellular retinaldehyde binding protein (CRALBP) and Brn3. This study demonstrates expression of NT4 by ganglion cells and shows expression of BDNF and NT4 in the outer photoreceptor segments is downregulated during PVR, whilst NT4 is markedly upregulated throughout the retina during this condition. The findings here suggest that NT4 may play a neural protective role during the development of PVR. It also shows that upregulation of NT4 in PVR is localised to Müller glial cells, indicating either over-expression of this factor by Müller cells or that Müller cells internalise NT4 for trafficking across the retina. TrkB expression was not observed in PVR retina. The observations that Müller glia demonstrate upregulation of NT4 suggests that retinal injury may lead to activation of this neurotrophin by Müller cells as part of their neuroprotective functions.

Vitreous and subretinal haemorrhage: an unusual complication of retinal racemose haemangioma.

Racemose haemangioma of the retina is a rare, usually unilateral developmental abnormality: an arteriovenous communication with variable alterations in capillary and arteriolar networks. Herein a case of a 57-year-old man with a vitreous and subretinal haemorrhage in the left eye is described.

Visual function and subjective perception of visual ability after macular hole surgery.

PURPOSE: To evaluate the functional and anatomical results of macular hole surgery and to explore its effect on patients' Health-Related Quality Of Life (HR-QOL) and to investigate the associations between self-reported HR-QOL and conventional measures of visual function. DESIGN: Case series. METHODS: The National Eye Institute 25-Item Visual Function Questionnaire (VFQ-25) and the 36-Item Short-Form Health Survey (SF-36) were self-administered by 30 patients before and 4 months after macular hole surgery. Preoperative, intraoperative, and postoperative clinical data were collected including visual acuity, contrast sensitivity, and metamorphopsia. Multi-item scales rating different aspects of HR-QOL were compared before and after surgery, and their correlation with traditional methods of outcome evaluation was analyzed. RESULTS: Macular hole closure was achieved in 26 patients (87%). Mean LogMAR visual acuity improved by 6 +/- 10 letters for distance and 7 +/- 12 letters for near. Metamorphopsia was reduced by a mean of 35 +/- 70 squares on Amsler chart, and Pelli-Robson contrast sensitivity decreased by a mean of -0.09 +/- 0.3 log units postoperatively. The VFQ-25 composite score as well as scale scores associated with general vision, near vision, vision-related mental health, and role difficulties were significantly improved (P < .05) after successful closure of macular hole. Conversely out of the eight SF-36 health concepts, limitation in usual role activities because of emotional problems was the only one that significantly improved postoperatively. Both baseline and postoperative best-corrected visual acuity significantly correlated with most of the VFQ subscale scores before and after surgery, respectively. CONCLUSIONS: In this case-series, macular hole surgery appears to have a beneficial effect on patients' subjective perception of visual function. The use of vision-targeted health status questionnaires in conjunction with detailed clinical examination provides a more comprehensive overview of individuals' daily well-being after surgical intervention. Further controlled studies are required to confirm our findings.