Unexplained vision loss following removal of epiretinal membrane.

PURPOSE: To report unexplained severe central vision loss accompanied by a dense central scotoma as an uncommon complication following epiretinal membrane removal. METHODS: Retrospective, multicentred, case series. RESULTS: Six patients underwent uncomplicated vitrectomy surgery between 2000 and 2007 at four separate retina practices for removal of an epiretinal membrane. Preoperative vision ranged from 20/60 to 20/100, with a median of 20/70. On the first day postoperatively, all patients noted decreased vision ranging from counting fingers to light perception and were found to have a dense central scotoma. Posterior segment examination revealed a white, oedematous macula in all affected eyes. Vision improved minimally during the follow-up period, which ranged from 2 months to 5 years. The final vision ranged from 20/200 to hand movements. No anatomic or physiologic cause for the decreased vision and central scotoma was identified. CONCLUSIONS: While uncommon, severe, permanent, central vision loss accompanied by a dense central scotoma can occur following epiretinal membrane removal and should be considered when assessing the risks and benefits of such surgery.

Use of digitized fluorescein angiogram system to evaluate laser treatment for subretinal neovascularization: technique.

In patients with subretinal neovascular membranes (SRNVM), persistence of the SRNVM after laser treatment is a major cause of decreased visual acuity. Persistence is associated with inadequate initial laser treatment. A technique using a digitized fluorescein angiogram (DFA) system is presented that allows immediate evaluation of the adequacy of laser treatment for SRNVM. This involves overlaying a red-free photograph taken after treatment on a fluorescein angiogram taken before treatment using a digital angiogram system that evaluates the adequacy of treatment. A protocol for augmentation of laser treatment has been developed that will aid in the reduction of persistence after laser treatment of SRNVM.

Evaluation of persistence of subretinal neovascular membranes using digitized angiographic analysis.

A study was conducted using the digitized fluorescein angiogram (DFA) system to evaluate adequacy of coverage of laser treatment for subretinal neovascular membranes (SRNVM) and to confirm that complete coverage lowers the incidence of persistent SRNVMs. Ten consecutive cases were evaluated with the DFA system after undergoing a single laser treatment. Three cases were judged to be adequately treated, and the remaining seven cases were judged to be inadequately treated. The DFA system was then used during photocoagulation in 16 consecutive cases to verify complete coverage of the SRNVM or to indicate the need for photocoagulation augmentation. Despite augmentation, 2 of the 16 cases remained inadequately treated. Overall, the cases that were adequately treated had a 12% (2/17) persistence rate, whereas those that were inadequately treated had a persistence rate of 67% (6/9). The data indicate that adequate coverage of SRNVMs is essential to prevent persistence.

Optimization of the signal-sequence cleavage site for secretion from Bacillus subtilis of a 34-amino acid fragment of human parathyroid hormone.

We have effected the secretion from Bacillus subtilis of a 34-amino acid (aa) fragment of human parathyroid hormone (PTH,1-34), using a Bacillus amyloliquefaciens neutral protease signal sequence. The secretion efficiency depended on the aa sequence near the signal-sequence cleavage site. We constructed a series of gene fusions encoding different pairs of aa between the signal sequence and PTH,1-34. There was a correlation between those polypeptides which were efficiently secreted and the potential for a beta-turn in the region just beyond the signal-sequence cleavage site. Based on this correlation, we constructed a gene fusion which specified Gly rather than Ala at the C terminus of the signal sequence, thus creating a beta-turn potential at the end of the signal sequence. The change provided a slight increase in secretion efficiency.