D. V. Do

The incidence of endophthalmitis following transconjunctival sutureless 25- vs 20-gauge vitrectomy

AimTo determine the incidence of endophthalmitis following 25-gauge and standard 20-gauge vitrectomy.MethodsIn this single-centre retrospective interventional case series, we evaluated the incidence of acute endophthalmitis occurring within the 14-day postoperative period in all patients who underwent pars plana vitrectomy between 1 November 2002 and 31 December 2006. A total of 3477 consecutive patients were identified. Of them, 3046 patients underwent 20-gauge vitrectomy and 431 underwent 25-gauge vitrectomy.ResultsThe event rates of postoperative endophthalmitis were 0.03% (1 of 3046) after 20-gauge vitrectomy and 0.23% (1 of 431) after 25-gauge vitrectomy (P=0.23). In the endophthalmitis case that occurred after 25-gauge vitrectomy, a combined phacoemulsification cataract surgery was performed with the 25-gauge vitrectomy. Analyses of event rates of postoperative endophthalmitis after combining phacoemulsification cataract surgery and vitrectomy were 0% (0 of 170) for 20-gauge vitrectomy and 2.17% (1 of 46) for 25-gauge surgery vitrectomy (P=0.21).ConclusionThe incidence of postoperative endophthalmitis following 25-gauge vitrectomy and 20-gauge surgery is low. Although there is a trend suggesting an increased risk of endophthalmitis with the 25-gauge system, this difference was not statistically significant given the low number of measured outcomes.

Spectral- and time-domain optical coherence tomography measurements of macular thickness in normal eyes and in eyes with diabetic macular edema

PurposeTo report macular thickness values in normal eyes and eyes with diabetic macular edema (DME) using time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT), and to derive a conversion equation.MethodsThe index study was a prospective investigation conducted on 80 eyes from 40 normal subjects and 130 eyes from 118 patients with DME seen in our clinic. Retinal thickness values from the central 1 mm of the macula and surrounding four ETDRS subfields were acquired using TD-OCT (Stratus OCT) and SD-OCT (SPECTRALIS HRA+OCT). Measurements of the central (C) subfield from both devices were used to derive a conversion equation. The equation was used to predict SD-OCT values using measurements from TD-OCT. Agreement between predicted and actual SD-OCT measurements was assessed.ResultsIn normal eyes, the mean difference between TD-OCT and SD-OCT measurements of the C subfield was 76 μm (CI95=74 and 77, respectively). The conversion equation, y=1.029x+72.49, was derived. In eyes with DME, using the equation, SPECTRALIS-predicted values were 5% higher than actual measurements, with 95% of predicted values falling within 9% of the actual measurements. Relocating SD-OCT grids to match the location on TD-OCT resulted in predicted values falling within 7% of actual measurements.ConclusionsThe percent difference between actual thickness measurements from SPECTRALIS and predicted thickness measurements, using the conversion equation, was within reported limits of repeatability of Stratus in eyes with DME. Our equation may help correlate OCT values from both devices in standard care and clinical trials for DME.

Factors affecting visual outcomes in patients with diabetic macular edema treated with ranibizumab

PurposeTo identify factors associated with visual outcomes in patients with diabetic macular edema (DME) treated with ranibizumab (RBZ) in the Ranibizumab for Edema of the mAcula in Diabetes—Protocol 2 (READ-2) Study.Patients and methodsOptical coherence tomography scans, fundus photographs, and fluorescein angiograms (FAs) were graded and along with baseline characteristics were correlated with month (M) 24 visual outcome of best-corrected visual acuity (BCVA) ≤20/100 (poor outcome) vs >20/100 (better outcome).ResultsOf 101 patients with a M20 visit or beyond, 27 (27%) had BCVA ≤20/100. Comparison of patients with or without poor outcome showed mean baseline BCVA of 16.8 letters (20/125) in the former compared with 30.4 letters (20/63; P<0.001). Mean change in BCVA between baseline and M24 was −2.6 letters in the poor outcome group compared with +9.8 letters (P<0.001). Foveal thickness (FTH) at M24 was 374.1 μm in the poor outcome group compared with 268.8 μm (P<0.01), a difference driven by 14 patients with mean FTH of 450.3 μm. Foveal atrophy occurred in 65% (11/17) in the poor outcome group compared with 17%(12/71, P=0.001). Persistent edema was noted in 52% (14/27) of patients with poor outcome. Laser scars near foveal center were significantly more common in patients with poor outcome who did not have edema vs those who did (78% (7/9) vs 23% (3/13) P=0.03).ConclusionPoor baseline BCVA (≤20/125) in DME patients predicts poor visual outcome (≤20/100) after 2 years of treatment with RBZ and/or focal/grid laser, often due to foveal atrophy and/or persistent edema.