Andrew J. Packer

Punctate inner choroidopathy

Ten moderately myopic women had blurred vision, light flashes, or paracentral scotomas associated with small yellow-white lesions of the inner choroid and pigment epithelium. Most lesions had an overlying serous detachment, were hyperfluorescent, and leaked fluorescein during the acute phase. The lesions healed into atrophic scars and became progressively more pigmented with time. Subretinal neovascular membranes later developed from scars in six patients. Vision was usually only minimally affected unless the lesions were subfoveal or unless choroidal neovascular membranes subsequently occurred. Extensive laboratory studies were noncontributory.

Terson's Syndrome: Clinicopathologic Correlations

In seven cases of Tersons syndrome, an elevated, dome-shaped, membrane was detected in the posterior pole by ophthalmoscopy, echography, or during pars plana vitrectomy. Light and electron microscopic examination of two additional eyes obtained postmortem from an acute case of Tersons syndrome revealed that the posterior vitreous face was elevated by blood and that the internal limiting membrane of the retina was intact and in its normal position. In two chronic cases, a dome-shaped epiretinal membrane was excised from the macula during vitrectomy. Light and ultrastructural studies demonstrated that the membranes consisted of glial cells and basement membrane material. The dome-shaped structure observed in eyes with Tersons syndrome is due to the formation of a subhyaloid hemorrhage. The partially detached posterior hyaloid face created by this hemorrhage provides a scaffold for cellular proliferation and the development of an elevated epiretinal membrane in long-standing cases. Echographically, this membrane resembles a retinal detachment in B-scans, but can be clearly distinguished from retina with standardized A-scan.

Procoagulant Effects of intraocular Sodium Hyaluronate (Healon) after Phakic Diabetic Vitrectomy: A Prospective, Randomized Study

A procoagulant effect was reported previously after injection of 0.50 to 0.75 ml of sodium hyaluronate (Healon) into the vitreous cavity at the end of phakic diabetic vitrectomies. A multicenter, randomized, prospective trial was done to study this effect. In the treatment group the media was clear in 50% of eyes in the immediate postoperative period compared with only 8% in the control group. At 2 to 6 weeks, there was no statistically significant difference between the two groups. The authors conclude that such sodium hyaluronate injection provides clear media in a significant number of eyes in the immediate postoperative period, potentially allowing thorough postoperative evaluation and early retinal photocoagulation if needed.

The Site of Operating Microscope Light-Induced Injury on the Human Retina

We determined the site of the focal illumination from the Zeiss OPMI-6 operating microscope on the retina of the phakic and aphakic human cadaver eye by directly observing the illuminating element image on the posterior scleral surface of the globe. With the eye straight ahead and the operating microscope level, the focal oval area of retinal illumination was located superior to the foveola in both the phakic and aphakic eye. Tilting the operating microscope 10 degrees toward the surgeon displaced the entire illuminating element image 0.50 mm below the foveola in the phakic eye and 0.25 mm below the foveola in the aphakic eye. Rotating the eye inferiorly 10 degrees displaced the entire illuminating element image 1.0 mm below the foveola in the phakic eye and 1.25 mm below the foveola in the aphakic eye. Centering the field of view superiorly (viewing the superior limbus) paradoxically displaced the illuminating element image inferiorly, resulting in central foveal illumination. Foveal light exposure was avoided in most eye positions by tilting the microscope at least 10 degrees toward the surgeon.

Sodium Hyaluronate (Healon®) in Closed Vitrectomy

Healon was implanted into the vitreous cavity of 33 eyes at the conclusion of pars plana vitrectomy. In aphakic eyes, Healon diffused rapidly into the anterior chamber, reducing the length of effective tamponade posteriorly and causing marked elevations of intraocular pressure. In phakic diabetic eyes, Healon appeared to trap hemorrhage mechanically from bleeding fibrovascular stumps posteriorly. It may therefore reduce the risk of opacifying vitreous hemorrhage after vitrectomy in phakic eyes with active neovascularization.

Fatty acid composition and arachidonic acid metabolism in vitreous lipids from canine and human eyes

About 55% of the acyl groups of dog and human vitreous are unsaturated fatty acids. The major components are oleate (18:1, n-9) and arachidonate (20:4, n-6) with moderate amounts of linoleate (18:2, n-6) and docosahexaenoate (22:6, n-3). Palmitate (16:0) and stearate (18:0) are the major saturated fatty acids. There are no significant changes between ages 37-82 years in the fatty acyl group content and composition of human vitreous. In vitreous from Irish setters with hereditary rod-cone dysplasia (RCD) the levels of oleate are decreased with a concomitant increase in arachidonate. [1-14C]Arachidonic acid was actively incorporated into canine vitreous glycerolipids both in vitro and in vivo. The incorporation was mainly into phosphatidylinositol, triacylglycerol, phosphatidylcholine and phosphatidylethanolamine. There were some differences in the pattern of incorporation between human and dog and between in vivo and in vitro incubations of canine vitreous. Glycerolipid acylation was significantly increased in phosphatidylinositol and phosphatidylcholine in RCD canine vitreous. The pattern of incorporation of [U-14C]docosahexaenoic acid into vitreous glycerolipids was different from arachidonic acid incorporation. Although vitreous did not produce any measurable enzymatic synthesis of cyclooxygenase and lipoxygenase products from [1-14C]-arachidonic acid in vitro, there was significant generation of autooxidation products. These results suggest an active lipid metabolism in vitreous.