Faculty Bibliography

PURPOSE: To describe anatomical relationships of retinal neovascular complexes (NVCs) and the posterior vitreous in proliferative diabetic retinopathy using spectral domain optical coherence tomography. METHODS: Cross-sectional study. Neovascular complexes were imaged using spectral domain optical coherence tomography in 51 eyes of 37 patients. The relationship of NVCs to the posterior vitreous cortex and posterior vitreous spaces, such as the premacular bursa, prevascular vitreous fissures, and perimacular cisterns, was analyzed. RESULTS: In the 77 NVCs evaluated, 61 (79%) had grown along the outer surface of the posterior hyaloid face, and vitreoschisis was present in 37 (48%). The "wolf's jaw" configuration was present in 9% and resulted from NVC arising from the arcades and proliferating along the posterior hyaloid face. By contrast, NVCs that invaded the bursa originated from smaller venous tributaries more distant from the arcades. The premacular bursa and prevascular vitreous fissure/perimacular cistern were invaded infrequently, respectively, in 15% and 38% (P = 0.137). CONCLUSION: Tomographic analysis of diabetic NVCs showed that most NVCs arise and grow along the posterior hyaloid face and that vitreoschisis is more prevalent than what has been found in ultrasound studies. The wolf's jaw configuration does not seem to result from the invasion of the bursa, as previously suggested.

Purpose: A macular hole (MH) is a pathological full thickness retinal defect in the macular region (MR). Interestingly, a MH always possesses a circular shape in the retinal plane. Present assumptions on MH etiology refer to tangential or anterior-posterior tensile forces at the foveal region. Using biomechanical models, we investigated the impact of biomechanical factors in macular region on the MH formation and its circular shape. Methods: 2D-and 3D-finite-element models of MR were developed based on optical coherence tomography (OCT) volume scans of a healthy eye. The models consist of two elastic layers: the internal limiting membrane (ILM: E=0.147MPa) and the retina (E=0.431MPa). Both materials were modeled as linearly elastic and incompressible. In the ILM in MR a small ellipsoidal slit was constructed as a precursor to a macular hole. In the 3D model, the axial ratio (minor d /major axis b, see Figure) of the initial constructed slit was determined assuming physiological intraocular pressure (IOP) range. In the 2D model, tangential and anterior-posterior tensile forces were applied to the intact ILM at specific angular vitreal attachments (shearing angle ranged 0degree-90degree). Maximal principal strains were computed, which are likely candidates of causing failure in the tissue and thus MH formation. Results: Under physiological IOP-conditions, the 2D model of MR without an initial slit shows high strains exactly in the area, where the MH formation is observed clinically. Using the 3D model further simulations under the same conditions show that an initial slit turns into an oval shape with a tendency to become round. When additional forces were considered in the attachment region of the vitreous it was observed that maximal principal strains in MR become larger with smaller shearing angle under predominant tangential forces. Tangential forces become greater than tensile forces hence being potentially riskier for MH progression. Conclusions: The IOP as single factor is not alone responsible for the circular formation of a MH from an initial slit. However, forces, especially tangential ones, transferred by the detaching vitreous result in high principal strains in MR. This aspect in combination with weakened tissue might lead to MH formation. Biomechanical modelling can be a useful tool for the investigation of MH etiology as well for the early MH diagnostics and the prediction of its progression

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. To compare the stages of vitreous degeneration in patients with vitreomacular traction (VMT) and macular holes (MH). Methods. A retrospective study was performed analyzing stages of vitreous degeneration of eyes with VMT or MH using swept-source optical coherence tomography (SS-OCT) and spectral-domain optical coherence tomography (SD-OCT). An analogous review was performed on a control group of eyes with contralateral posterior vitreous detachments. Thirty-four eyes with VMT/MH and 39 control eyes were reviewed. Results. Twenty-seven VMT/MH eyes and 31 control eyes were included. Eyes with VMT/MH demonstrated significantly earlier stages of vitreous degeneration when compared to the control group (p = 0.048) despite significantly greater age (p = 0.032). Conclusions. Vitreoretinal interface disease is more often associated with a formed vitreous and an intact premacular bursa. This is contrary to previous assumptions implicating degeneration of vitreous as a precipitating factor of interface disease when in conjunction with abnormal vitreomacular separation.

PURPOSE: To report a giant retinal pigment epithelium rip in a patient with a bullous retinal and choroidal detachment. METHODS: Case report with widefield imaging, fundus autofluorescence, and optical coherence tomography of the retina. RESULTS: This 62-year-old patient had a history of advanced glaucoma, trabeculectomy, blebitis, and endophthalmitis. He had cataract surgery 6 weeks before presentation. He was found to have a large bullous retinal and choroidal detachment with a large retinal pigment epithelium tear at the limit of the choroidal detachment. After vitrectomy for retinal detachment repair, the tear was observed to extend inferiorly at the margins of the choroidal detachment. CONCLUSION: This case report demonstrates that large retinal pigment epithelium rips can be found associated with large bullous choroidal and retinal detachments. These tears seem similar to tears that have been observed after trabeculectomy.

PURPOSE: To survey the surgical routines with regards to prophylactic strategies in a sample of Italian hospitals and compare these with European Society for Cataract and Refractive Surgery (ESCRS) guidelines. METHODS: Six private and 18 public hospitals were included in this clinical-based retrospective study. The overall volume of cataract operations in the 24 centers in 2013 was 43,553. Main outcome measure was incidence of endophthalmitis per 1,000. An incidence of less than 0.13% was considered acceptable. RESULTS: Our study provides the first Italian data on the use of intracameral antibiotics in cataract surgery as recommended by the ESCRS. Thirteen centers (54%) used intracameral cefuroxime at the end of surgery. Of the 13 centers that used cefuroxime, 8 (62%) had an incidence of endophthalmitis less than 0.13%. Of the 7 (29%) centers that did not use intracameral cefuroxime, all had an endophthalmitis rate of greater than 0.13%. This difference was statistically significant (p<0.05). Among the 4 centers not included, 2 used vancomycin in the infusion bottle, 1 a fluoroquinolone, and the last a combination of antibiotics. The majority of surgeons (71%) used preoperative antibiotic eyedrops, but this measure was not shown to be significantly protective. CONCLUSIONS: Slightly more than half of the centers surveyed in this study adhered to the recommendations of the ESCRS and routinely employed prophylactic intracameral cefuroxime. An incidence of endophthalmitis greater than 0.13% was encountered significantly more frequently among centers that did not employ intracameral cefuroxime.