Surgical demonstration of pressure differential through an optic disc pit.

PURPOSE: To demonstrate intraoperative dynamic flow through an optic disc pit. METHODS: Retrospective interventional case report. RESULTS: Surgical management of an optic disc pit involved standard 25-gauge pars plana vitrectomy, induction of posterior hyaloid separation with triamcinolone stain, temporal peripapillary laser and SF6 gas. Intraoperatively a remnant of stained vitreous at the optic disc head prolapsed into the optic disc pit with higher intraocular pressure but was drawn back into the vitreous cavity as the intraocular pressure was lowered. This clearly demonstrated a pressure differential across the pit. CONCLUSION: Communication between the vitreous cavity and the perineural space of the optic nerve is described histologically. Our case demonstrated dynamic flow through the optic disc pit with intraoperative fluctuation of intraocular pressure.

Fatal air embolism during endoresection of choroidal melanoma.

PURPOSE: To describe a case of intraoperative mortality because of air embolism during resection of a choroidal melanoma by pars plana vitrectomy. METHODS: Retrospective interventional case report. RESULTS: A 69-year-old man died unexpectedly at the time of pars plana vitrectomy. The operative technique involved the use of high-pressure air (60 mmHg) in the presence of traumatically exposed choroidal vasculature. Autopsy revealed a large air embolus in the right ventricle, which resulted in sudden cardiovascular collapse. CONCLUSION: Air embolism is a rare complication of ophthalmic surgery. Infusion of air in the presence of traumatically exposed choroidal vasculature exposes the patient to the risk of air embolism. Ophthalmic surgeons and anesthetists should be aware of the possibility of air embolism during certain ophthalmic procedures, and appropriate intraoperative monitoring should be considered.

Brachytherapy and endoresection for choroidal melanoma: a cohort study.

AIM: To report and compare the outcomes of brachytherapy and endoresection in the conservative treatment of medium sized choroidal melanoma. METHODS: A retrospective cohort study. Medium tumours were defined as 2.5-10 mm in height and less than 16 mm in the widest diameter. Consecutive patients undergoing brachytherapy at Groote Schuur Hospital were compared with a cohort undergoing endoresection from a national database. RESULTS: 148 brachytherapy and 22 endoresection patients were followed for a median of 55.4 and 62.4 months, respectively. Tumours undergoing endoresection were thicker (7.3 vs 4.9 mm, p<0.001, Wilcoxon rank-sum test) and further from the fovea (5.2 vs 3.7 mm, p=0.05, Wilcoxon rank-sum test) than those treated with brachytherapy. Visual acuity of 6/18 or better was maintained in 41% of the endoresection group and 35% of the brachytherapy group. The likelihood of achieving a final visual acuity of better than 2/60 was 22% higher in the endoresection group (risk ratio 1.22, 95% CI 1.02 to 1.28, p=0.034). Rates of local recurrence (18.2% vs 14.9%, p=0.75) and metastases or death (18.2% vs 14.2%, p=0.75) were higher in the endoresection group, and the enucleation rate was lower in this group (4.6% vs 10.8%, p=0.70) but these were not statistically significant. CONCLUSIONS: The outcomes observed in this small cohort of endoresection patients suggest that endoresection of selected tumours may achieve better visual outcomes than brachytherapy. Rates of local recurrence, enucleation and metastases following endoresection require further research. Local recurrence is likely to be influenced by consolidation treatment methods.