Faculty Bibliography

Vitreous occlusion of a glaucoma drainage implant (GDI) can lead to failure of the device and severely elevated intraocular pressure. The pathophysiology of tube obstruction is related to central and anterior displacement of vitreous that is drawn into and condenses within the proximal lumen of the tube. This can occur from days to years following GDI surgery. Successful management of vitreous-tube obstruction generally requires manual removal of the condensed vitreous plug with end-grasping forceps. This technique achieves reversal of tube blockage and restoration of GDI function. Amputation of the incarcerated vitreous alone with vitrectomy or neodymium:yttrium-aluminum-garnet vitreolysis does not consistently restore GDI function and risks persistent intraluminal tube obstruction.

PURPOSE: To compare the antibiotic susceptibilities and visual acuity (VA) outcomes in endophthalmitis caused by methicillin-resistant (MRSA) versus methicillin-sensitive S. aureus (MSSA). METHODS: The records of 34 cases of S. aureus endophthalmitis at The New York Eye and Ear Infirmary from Jan 1997 to June 2011 were reviewed. Antibiotic susceptibility profiles over time and VA at presentation and at 3, 6, and >/=12 months were recorded. S. aureus isolates were grouped based on oxacillin resistance. RESULTS: Of the 34 cases, 15 (44 %) were MRSA and 19 (56 %) MSSA. Median presenting VA was hand motions (logMAR 4.0) in both the MRSA and MSSA groups. There was no statistically significant difference in VA between the MRSA and MSSA groups at 3, 6, or >/=12 months. No MRSA isolates were resistant to vancomycin or gentamicin. While over 85 % of MRSA isolates tested for fourth-generation fluoroquinolones were resistant, just 10 % MSSA isolates tested were resistant. There was a trend suggesting an increase in the proportion of MRSA isolates compared to MSSA isolates over the course of the study period. CONCLUSIONS: There was no statistical difference in short- or long-term VA outcomes between the MRSA and MSSA groups at any time point. Resistance to fourth-generation fluoroquinolones was present in over 85 % of MRSA isolates, but just 10 % of MSSA isolates. An increasing proportion of MRSA amongst S. aureus isolates was noted over the course of the study period.

PURPOSE/OBJECTIVE:To examine the utility of perfluoro-n-octane (PFO) in balanced salt solution (BSS) to shield the macula from the impact of dropped metallic intraocular foreign bodies (IOFBs) by modeling scenarios in which they may fall during surgical removal. METHODS:Model eyes were filled with various fluid mixtures (Group 1: 10% PFO/90% BSS; Group 2: 100% BSS; Group 3: 100% PFO; Group 4: 10% PFO/90% air; Group 5: 10% BSS/90% air). In Groups 1, 4, and 5, the 10% fluid volume covered the theoretical macula. For each fluid mixture, up to 30 IOFB drop scenarios were performed for each of the 5 sample IOFBs from 3 locations. Trajectories were recorded using a camera attached to a Zeiss operating microscope (Carl Zeiss, Jena, Germany). The percentages of IOFBs impacting the macula were calculated and Fisher exact test was used to assess differences. RESULTS:In Group 1, 93% (417/450) of the dropped IOFBs were deflected by the PFO-BSS interface compared with 0% (0/500) in Groups 2, 3, 4, and 5 (P < 0.01). With the exception of the heaviest IOFB (24.4 mg), which impacted the macula in 30% of tests when dropped from the superior posterior segment (P < 0.01), all other IOFBs (2.8-13.4 mg) were deflected by the PFO-BSS interface in 100% of Group 1 drops (P < 0.01). CONCLUSION/CONCLUSIONS:As demonstrated by these simulations, the PFO-BSS interface can deflect IOFBs dropped during surgery in a wide range of scenarios, especially when the IOFB is of lower mass.

PURPOSE/OBJECTIVE:To report two cases of spontaneous Retisert implant dissociation with dislocation of the medication reservoir into the anterior chamber. DESIGN AND METHODS/METHODS:Case reports. RESULTS:Two patients with chronic, noninfectious uveitis following Retisert implantation between 6 and 7 years prior presented with a complaint of a "white spot" in their right eyes. Both patients had previous pars plana vitrectomies. Anterior segment examination revealed a dislocated medication reservoir of the Retisert implant in the inferior portion of anterior chamber with associated reservoir-corneal endothelial touch and stromal edema. The reservoirs were subsequently retrieved via a pars plana approach and removed from the anterior chamber through a corneal incision. CONCLUSIONS:Spontaneous dissociation of the Retisert implant with dislocation of the medication reservoir into the anterior chamber can be a late complication of Retisert implantation. Eye care professionals and patients should be aware of this complication, particularly with long-term intraocular retention of this device.

PURPOSE/OBJECTIVE:To describe a new method of retinal vascular perfusion density mapping using optical coherence tomography angiography and to compare current staging of diabetic retinopathy based on clinical features with a new grading scale based on perifoveal perfusion densities. METHODS:A retrospective review was performed on subjects with diabetic retinopathy and age-matched controls imaged with a spectral domain optical coherence tomography system (Optovue XR Avanti, Fremont, CA). Split-spectrum amplitude-decorrelation angiography (SSADA) generated optical coherence tomography angiograms of the superficial retinal capillaries, deep retinal capillaries, and choriocapillaris. Skeletonized optical coherence tomography angiograms were used to create color-coded perfusion maps and capillary perfusion density values for each image. Capillary perfusion density values were compared with clinical staging, and groups were compared using analysis of variance and Kruskal-Wallis analyses. RESULTS:Twenty-one control and 56 diabetic retinopathy eyes were imaged. Diabetic eyes were grouped according to clinical stage. Capillary perfusion density values from each microvascular layer were compared across all groups. Capillary perfusion density values were significantly lower in nearly all layers of all study groups compared with controls. Trend analysis showed a significant decrease in capillary perfusion density values as retinopathy progresses for most layers. CONCLUSION/CONCLUSIONS:Quantitative retinal vascular perfusion density mapping agreed closely with grading based on clinical features and may offer an objective method for monitoring disease progression in diabetic retinopathy.