Structural and functional implications of severe foveal dystopia in epiretinal membranes.

PURPOSE: The purpose of this study was to examine the functional and structural correlates of severe foveal dystopia in patients with epiretinal membranes. METHODS: For this retrospective study of 29 eyes with epiretinal membrane, we identified 7 eyes that had severe foveal dystopia (defined as fovea located >200 µm from its expected location) and followed the direction and rate of foveal movement pre- and postoperatively. RESULTS: Epiretinal membrane traction caused the fovea to move preoperatively at a rate of 275 µm/month from its anatomical location in 2 patients. The final preoperative foveal location was, on average, 1,217 ± 683 µm away from its expected location. Postoperatively, foveal movement toward its expected location was largest during the first month after surgery (mean = 547 ± 340 µm) and slowed down until the final follow-up position was achieved (mean = 301 ± 131 µm). Overall, the fovea moved a total of 848 ± 445 µm, allowing the fovea to correct only 32.8 ± 22.1% of the total displacement from its expected location. A univariate regression model confirmed a linear relationship between preoperative visual acuity and preoperative foveal distance from its expected anatomical location with an R of 0.759 (P = 0.0107). CONCLUSION: The extent of tractional foveal dystopia correlates with decreased visual acuity. Although all patients experienced functional and anatomical improvements with surgery, long-standing or severe foveal dystopia may be associated with permanent structural changes that limit functional outcome. Cases with extreme degrees of foveal dystopia may benefit from early intervention to prevent irreversible structural and functional changes.

Bacterial contamination of ocular surface and needles in patients undergoing intravitreal injections.

PURPOSE: To evaluate potential sources of bacterial contamination during intravitreal (IVT) injection procedures. METHODS: Patients scheduled for IVT injection were asked to enroll in the study at the California Vitreoretinal Center (Menlo Park, CA) and the Vantage Eye Center (Salinas, CA) between October 2004 and April 2005. A total of 104 patients participated in the study, with a total of 118 IVT injection procedures performed on 107 eyes. Standard microbiological techniques were used to culture, identify, and quantify bacterial contamination of injection needles and the bulbar conjunctiva at the injection site in patients undergoing IVT injections. The main outcomes measured were type and quantity of bacterial isolates. RESULTS: Two (2%) of 114 needles collected were contaminated with bacteria. The prevalence of bacterial contamination of the injection site on the bulbar conjunctiva was 43% before prophylaxis on the day of the injection with topical antibiotics and povidone-iodine, with a statistically significant reduction to 13% after prophylaxis (P < 0.0001). Coagulase-negative Staphylococcus, the most common bacterium isolated from the ocular surface, was isolated from both culture-positive needles. CONCLUSIONS: IVT injection needles became contaminated with bacteria during the injection procedure. Although the contamination rate was low, this supports a mechanism of postinjection endophthalmitis in which there is direct inoculation of ocular surface flora into the vitreous cavity by the injection needle.

Intraocular pressure and ocular pulse amplitude comparisons in different types of glaucoma using dynamic contour tonometry.

PURPOSE: To compare the intraocular pressures (IOP) and ocular pulse amplitudes (OPA) in patients with different types of glaucoma, ocular hypertension (OHT), and normal controls (NC) using dynamic contour tonometry (DCT) and the goldmann applanation tonometry (GAT). METHODS: 906 eyes of 501 adult patients in the following five groups were included in this cross-sectional study: primary open angle glaucoma (POAG), normal tension glaucoma (NTG), Pseudoexfoliative Glaucoma (PXG), OHT, and NC. The following tests were performed simultaneously during a single visit: IOP using DCT and GAT; OPA using DCT and central corneal thickness (CCT) using ultrasound pachymetry. Mixed effects regression models were used to compare the DCT and GAT IOP measurements in the five groups; the effect of CCT on IOP and the relationship between OPA and IOP within each group. RESULTS: DCT consistently had higher IOP values than GAT in POAG, PXG, NTG, and controls (p < 0.001) but not in OHT (p = 0.84). DCT IOP did not change while GAT IOP showed a non-significant increase (p = 0.09) with increased corneal thickness in each group. OPA was found to be highest in OHT (3.61 mmHg) and lowest in the control group (2.86 mmHg) and significantly increased with IOP in all groups. CONCLUSIONS: DCT measures an IOP that is significantly higher than GAT IOP in glaucoma and control subjects but not in ocular hypertensives. Furthermore, the DCT may measure an IOP that is independent of the CCT, which may not be true for the GAT, which increases with the CCT. OPA was highest in OHT and may be affected by the IOP.

Developmental endothelial locus-1 (Del-1), a novel angiogenic protein: its role in ischemia.

BACKGROUND: Developmentally regulated endothelial locus-1 (Del-1) is an extracellular matrix protein that is expressed by endothelial cells during embryological vascular development. We speculated that Del-1 may be reexpressed in ischemia and may be involved in endogenous angiogenesis. METHODS AND RESULTS: Del-1 protein was detected by immunohistochemistry in murine ischemic hindlimb after femoral artery excision. To determine whether exogenous Del-1 would augment angiogenesis in vivo, Del-1 or vehicle was administered for 3 weeks by intramuscular injection of murine ischemic hindlimbs. Angiogenesis was quantified by gadolinium-MRI perfusion and capillary densitometry. We used a disc angiogenesis system (DAS) to characterize the angiogenic response to vehicle (PBS), Del-1, Del-1 mutant (altered RGD domain), Del-1 minor (truncated discoidin-I-like domain), or basic fibroblast growth factor. After 14 days, the discs were extracted and sectioned to quantify vascular growth by morphometry. Endogenous Del-1 protein expression was increased in ischemic hindlimbs. Administration of Del-1 increased hindlimb vascular flow index and capillary density. In the DAS, Del-1 doubled fibrovascular growth, as did basic fibroblast growth factor. However, angiogenesis was not enhanced by the Del-1 mutant or Del-1 minor proteins. CONCLUSIONS: Del-1 is expressed in ischemic tissue. Del-1 stimulates angiogenesis, an effect that is dependent on the RGD motif and a second signaling sequence in the discoidin-I-like domain. Exogenous intramuscular administration of Del-1 significantly enhances angiogenesis in the murine ischemic hindlimb. Del-1 may prove to be a novel therapeutic agent for patients with ischemia.