Residual edema evaluation with ranibizumab 0.5 mg and 2.0 mg formulations for diabetic macular edema (REEF study).

PURPOSE: To compare the efficacy of ranibizumab 0.5-mg and 2.0-mg intravitreal injections for persistent diabetic macular edema (DME) previously treated with bevacizumab. METHODS: In all, 43 patients with residual center-involved DME following intravitreal bevacizumab were included in this 12-month prospective, nonrandomized, multicenter study. Enrolled patients received three monthly ranibizumab 0.5-mg injections. At month 3, patients with residual macular edema switched to three monthly injections of ranibizumab 2.0-mg. Assessments included monthly visual acuity and spectral-domain optical coherence tomography. RESULTS: Mean visual acuity improved by +6.4 letters at month 3 and +8.8 letters at month 6. Mean central subfield thickness (CST) decreased by -113 µm at month 3 and -165 µm at month 6. Before enrollment, 29/43 (67.4%) patients showed <10% CST reduction following monthly bevacizumab treatment. After three monthly ranibizumab 0.5-mg injections, 22/29 (75.9%) patients showed >10% reduction in CST, whereas 6 showed <10% reduction. Of these six, three (50%) showed >10% reduction in CST after switching to three monthly ranibizumab 2.0-mg doses. No serious adverse events were observed to month 6. CONCLUSION: Ranibizumab 0.5-mg or 2.0-mg may improve visual and anatomic outcomes in patients with DME who demonstrated minimal or no response to bevacizumab therapy. Moreover, increased dosage of ranibizumab (2.0-mg) may provide additional benefit over ranibizumab 0.5-mg in some patients. However, 2.0-mg ranibizumab is not currently commercially licensed or available.

Short-term study of allogeneic retinal pigment epithelium transplants onto debrided Bruch's membrane.

PURPOSE: To investigate the survival and behavior of retinal pigment epithelium (RPE) microaggregates transplanted onto hydraulically debrided Bruch's membrane and to compare results of using three different vehicles for cell delivery. METHODS: RPE microaggregates obtained from male cats were transplanted onto the tapetal area of female cats after native RPE was debrided. For the control, one of three vehicles was introduced into the debridements. Each transplant or control specimen was analyzed histologically and immunohistochemically. Transplanted male RPE cells were identified by in situ labeling of the cat Y chromosome. RESULTS: Histologically, significant numbers of condensed, darkly stained RPE nuclei were observed in all transplants compared with few TUNEL-positive RPE cells. Cellular retinaldehyde-binding protein was present up to day 7 in all RPE cells in transplants. In both transplant and control specimens, the antibody against the Ki-67 nuclear antigen labeled some RPE cells at day 3. TUNEL-positive outer nuclear layer nuclei were most frequently observed at day 1, but were much less frequent at 7 days in both transplant and control specimens. CONCLUSIONS: Transplanted RPE appeared to retain at least some markers of differentiation up to 7 days after surgery. Some proliferation of transplanted RPE cells was also seen. Apoptotic cell death of transplanted RPE, as judged by TUNEL staining was observed rarely. RPE transplants imposed no adverse effect on the overlying retina. RPE survival appeared to be similar with each of the three vehicles for cell delivery.

Endophthalmitis.

Endophthalmitis is an inflammatory reaction of intraocular fluids or tissues. Infectious endophthalmitis is one of the most serious complications of ophthalmic surgery. Occasionally, infectious endophthalmitis is the presenting feature of an underlying systemic infection. Successful management of infectious endophthalmitis depends on timely diagnosis and institution of appropriate therapy. Recognition of the different clinical settings in which endophthalmitis occurs and awareness of the highly variable presentation it may have facilitate timely diagnosis. Biopsy of intraocular fluid/tissue is the only method that permits reliable diagnosis and treatment. The different presenting clinical settings, a rational approach to diagnosis (i.e., when, what, and how to biopsy), and the treatment of infectious endophthalmitis are reviewed.

Clinicopathological correlation of primary and recurrent choroidal neovascularisation following surgical excision in age related macular degeneration.

AIMS/BACKGROUND: Fluorescein angiography and histopathological findings were correlated in two patients with recurrent choroidal neovascular membranes (CNVs) in an attempt to gain insight into the possible causes of recurrent CNVs and into the healing response after CNV excision. METHODS: Two patients with recurrent CNVs underwent repeat excision, and the excised tissue was studied with light and electron microscopy. RESULTS: Incomplete CNV excision probably led to the recurrences. The portion initially excised appears to have been anterior to the RPE in case 1. In both cases, recurrent CNVs contained RPE-like like cells suggesting that native RPE can repopulate the dissection bed. The tissue excised at the second operation contained areas with hyperplastic RPE and fragments of Bruch's membrane (external to the RPE basement membrane) in a matrix of fibrillar collagen and fibrocytes, suggesting that initial removal of the CNV can be followed by an abnormal anatomical arrangement of RPE and scarring of Bruch's membrane. CONCLUSIONS: Abnormal resurfacing of the dissection bed by RPE and fibroblasts may underlie, in part, the limited visual outcome often seen after surgical excision of CNVs in age related macular degeneration.

Progressive presumed choriocapillaris atrophy after surgery for age-related macular degeneration.

PURPOSE: The authors sought to evaluate the progression of presumed choriocapillaris atrophy after surgical excision of a subfoveal choroidal neovascular membrane (CNV) in an 80-year-old man with age-related macular degeneration. METHODS: The CNV was excised using a conventional three-port vitrectomy with subretinal dissection. The excised tissue was studied with light and electron microscopy. Preoperative and serial postoperative fluorescein angiograms (FA) and fundus photographs were obtained to study the dissection bed. RESULTS: Seven days after surgery, the FA showed hyperfluorescence in the area previously occupied by the CNV. Six weeks after surgery, this area showed retinal pigment epithelium (RPE) depigmentation, atrophy, or both on clinical examination, and the FA showed presumed choriocapillaris nonperfusion. Seven months after surgery, the area of the RPE depigmentation or atrophy and the corresponding area of presumed choriocapillaris nonperfusion had enlarged. The area of depigmentation or atrophy continued to enlarge for 1 year after surgery. Histologically, the excised CNV specimen disclosed RPE cells but no choriocapillaris. CONCLUSIONS: Presumed choriocapillaris nonperfusion after CNV excision may be due to RPE removal at surgery and may progress postoperatively.

In vitro transplantation of fetal human retinal pigment epithelial cells onto human cadaver Bruch's membrane.

Retinal pigment epithelium transplantation has been proposed as adjunctive treatment for age-related macular degeneration following surgical excision of choroidal neovascular membranes. The goal of this study was to develop a model to evaluate retinal pigment epithelium transplantation onto human Bruch's membrane in vitro. We investigated the ability of cultured fetal human retinal pigment epithelium to colonize human cadaver Bruch's membrane, determined the incubation time needed to form a monolayer and to exhibit apical microvilli and tight junctions, and assessed the production of basement membrane. Freshly enucleated (less than 48 hours old) human eyes were cut through the pars plana, and the anterior segment, vitreous, and retina were removed. The native retinal pigment epithelium was debrided with a surgical sponge. Bruch's membrane and choroid at the macula were trephined with a 7.0 mm diameter trephine and then incubated with 1/2 ml of Dulbecco's modified Eagle's medium +15% fetal calf serum+basic fibroblast growth factor (1 ng ml-1), and fetal human retinal pigment epithelium at a concentration of 242,000 cells ml-1. Specimens were incubated for 1, 4, 6, 8, 12, or 24 hours. The specimens were fixed in half strength Karnovsky's fixative, processed, and analysed with scanning and transmission electron microscopy. The retinal pigment epithelium covered the debrided macular specimens to different degrees at different incubation times. After 1 hour, the cells started to attach and flatten (median percent coverage: 78%). The extent of Bruch's membrane coverage by fetal retinal pigment epithelium varied greatly between specimens. After 4-6 hours, the cells covered the entire debrided surface in a monolayer (median percent coverage: 97.2% at 4 hours, 99.8% at 6 hours). Tight junctions were observed, and the cells had few apical microvilli. The lateral cell borders were obliquely oriented with respect to Bruch's membrane, and the nuclei were elongated, exhibited prominent nucleoli, and were oriented parallel to Bruch's membrane. After 6-8 hours, cells started to become hexagonal (median percent coverage at 8 hours: 99.97%). Cells attached to the inner collagenous layer tended to be flatter than cells attached to residual native basement membrane. At 12 and 24 hours, expression of hexagonal shape, tight junctions, and apical microvilli were observed more frequently (median percent coverage: 99.87% at 12 and 100% at 24 hours). No newly formed basement membrane was observed at these time points. In separate experiments comparing attachment in the presence and absence of native RPE basement membrane, the presence of native retinal pigment epithelial basement membrane promoted the early attachment of the cells and more rapid expression of normal morphology. This in vitro system provides a reproducible way to study the adherence of retinal pigment epithelium to normal and diseased human Bruch's membrane.

Clinicopathological correlation of an excised choroidal neovascular membrane in pseudotumour cerebri.

AIMS/BACKGROUND: To correlate the histopathology of an excised choroidal neovascular membrane (CNV) with the clinical and angiographic findings in a 32-year-old woman with pseudotumour cerebri and a peripapillary CNV with subfoveal extension. METHODS: The patient's visual acuity was assessed by individuals experienced in low vision refraction and who were not members of the surgical team. The CNV was excised via a conventional three port vitrectomy with subretinal dissection. The excised tissue was studied with light and electron microscopy. Preoperative and serial postoperative fluorescein angiograms (FAs) and fundus photographs were obtained to study the dissection bed. RESULTS: One week after surgery, the FA showed mottled subfoveal choriocapillaris perfusion. Three weeks after surgery, this area showed retinal pigment epithelium (RPE) atrophy clinically, and the FA showed choriocapillaris non-perfusion. Six months after surgery, the area of RPE atrophy and the corresponding area of choriocapillaris non-perfusion had expanded. Histologically, the excised CNV disclosed hyperplastic RPE, fibrovascular tissue, and no choriocapillaris. Fragments of RPE basement were present along the external edge of the specimen. The patient's visual acuity did not improve significantly after surgery. CONCLUSIONS: Choriocapillaris non-perfusion can develop even in young patients following CNV excision. In this particular case, it is believed that choriocapillaris atrophy was caused by incomplete ingrowth of RPE into the dissection bed following RPE removal with CNV excision. As far as is known, this is the first report describing the results of surgery for CNV secondary to papilloedema associated with pseudotumour cerebri.