Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation

AIM：To compare accuracy,reproducibility and test duration for the Snellen and the Early Treatment Diabetic Retinopathy Study（ETDRS）charts,two main tools used to measure visual acuity（VA）.·M ETHODS：A computer simulation was programmed to run multiple virtual patients,each with a unique set of assigned parameters,including VA,false-positive and false-negative error values.For each virtual patient,assigned VA was randomly chosen along a continuous scale spanning the range between 1.0 to 0.0 log MAR units（equivalent to 20/200 to 20/20）.Each of 30 000virtual patients were run ten times on each of the two VA charts.·RESULTS：Average test duration（expressed as the total number of characters presented during the test±SD）was12.6±11.1 and 31.2±14.7 characters,for the Snellen and ETDRS,respectively.Accuracy,defined as the absolute difference（±SD）between the assigned VA and the measured VA,expressed in log MAR units,was superior in the ETDRS charts：0.12±0.14 and 0.08±0.08,for the Snellen and ETDRS charts,respectively.Reproducibility,expressed as test-retest variability,was superior in the ETDRS charts：0.23±0.17 and 0.11±0.09 log MAR units,for the Snellen and ETDRS charts,respectively.·CONCLUSION：A comparison of true（assigned）VA to measured VA,demonstrated,on average,better accuracy and reproducibility of the ETDRS chart,but at the penalty of significantly longer test duration.These differences were most pronounced in the low VA range.The reproducibility using a simulation approach is in line with reproducibility values found in several clinical studies.

Treatment of Coats' disease: an analysis of pooled results

AIM: To elucidate the association of treatment modality to vitreoretinal fibrosis and traction retinal detachment(TRD) in Coats' disease.METHODS: A PubMed search for Coats' disease with included studies describing eyes with clinical features and treatment course of Coats' disease. Binary logistic regression with fibrosis at presentation and treatment type as independent variables was performed to determine predictors of TRD historically(since 1921) and in the antivascular endothelial growth factor(VEGF) era(since2007). Odds ratios(OR) with 95% confidence intervals(CI)reported.RESULTS: Of 175 articles described 1183 eyes. Vitreoretinal fibrosis increased from presentation(5.4%) to follow-up(15.5%) and TRD increased from 0.44% to 3.9% at follow up. Laser was protective against vitreoretinal fibrosis(OR0.6, 95%CI 0.4-0.9) but TRD was borderline(OR 0.6, 95%CI0.3-1.1). Cryotherapy showed a higher association with TRD(OR 1.9, 95%CI 1.0-3.7) than with vitreoretinal fibrosis(OR 0.8, 95%CI 0.5-1.2). Similarly, intravitreal anti-VEGF alone was not associated with fibrosis(OR 1.1, 95%CI 0.6-1.8) nor TRD(OR 1.1, 95%CI 0.5-2.6) but the combination of laser and anti-VEGF therapy was protective [Fibrosis: 0.1(0.03, 0.35); TRD: 0.05(0.01, 0.23)] compared to anti-VEGF plus cryotherapy(P<0.001). Disease stage ≤2 B or ≥3 A was not associated with TRD.CONCLUSION: Vitreoretinal fibrosis and TRD increase after treatment in Coats' disease. The combination of antiVEGF agents and cryotherapy may lead to higher risk for TRD. Presence of pre-treatment fibrosis is the highest risk factor for post-treatment worsening of vitreoretinal fibrosis and TRD.

International multi-center study of iatrogenic retinal tears in pars plana vitrectomy

AIM: To study and compare the effect of different surgical settings on the development of iatrogenic retinal tears(IRT) in conventional(20-gauge) and microincisional vitrectomy.METHODS: An international retrospective comparative study of 394 patients who had simple vitrectomy at three tertiary centers. Surgeries were performed by four retina surgeons using different viewing systems. Two groups of eyes were compared: microincisional vitrectomy(327 eyes) and conventional(67 eyes) vitrectomy. An iatrogenic tear was defined as the occurrence of one or more peripheral retinal tears during surgery or at any visit in the first 6 wk postoperatively.RESULTS: Mean age was 67±12 y and 55% were female. Iatrogenic tears occurred in 11/394(2.8%) of eyes. The rate of tears was similar among different surgeons and viewing systems(P=0.93 and P=0.76, respectively). Surgical indication, preexisting pseudophakia/aphakia, induction of posterior vitreous detachment(PVD) during surgery, and the use triamcinolone acetonide didn’t significantly affect the rate of tears(P>0.1 for all factors). A higher rate of tears was found in the conventional group compared to the microincisional group(respectively, 7.5%, 1.8%, P=0.02).CONCLUSION: The rate of IRT in vitrectomy is not significantly affected by surgical indication, preexisting PVD or pseudophakia, or use of triamcinolone or different viewing systems but is significantly higher in conventional vitrectomy. Microincisional platforms improve the safety of vitrectomy regardless of the viewing system used.

Role of home monitoring with iCare ONE rebound tonometer in glaucoma patients management

AIM: To evaluate intraocular pressure(IOP) measurements and fluctuations using the i Care ONE rebound tonometer(RT-ONE), during home monitoring, in diagnosed and suspected glaucoma patients.METHODS: A retrospective case series of consecutive patients with known glaucoma or glaucoma suspects who were followed-up and treated between January 2016 and January 2017. The study included 80 eyes of 40 patients with a mean age of 59.1±14.6 y(range, 24-78). All patients have undergone 4-5 d of IOP home monitoring with RT-ONE at morning, noon, afternoon, and night time.RESULTS: Baseline mean IOP, as measured in the clinic(8 a.m.-12 p.m.), was 17.4±5.1 mm Hg, compared to RT-ONE home monitoring mean IOP of 15.6±4.1 mm Hg(P=0.002). Mean IOP was significantly lower at noon, afternoon and night times compared to clinic measured IOP and morning measurements(P=0.005). IOP peak measured during home monitoring was significantly higher compared to the clinic measured IOP(21.3±5.6 mm Hg and 17.4±5.1 mm Hg, P<0.001). IOP peaks during home monitoring demonstrated a majority of 47 peaks during morning measurements, compared to 23 at noon, 19 at afternoon and only 12 at night(P<0.001). The home monitoring results led to treatment modification of 44 eyes(55%), treatment regime was insufficient for 40(50%) eyes.CONCLUSION: Home monitoring IOP with RT-ONE can provide good assessment of mean IOP, IOP fluctuations and peaks throughout the hours of the day, which lead to an accurate treatment for glaucoma patients.