Rapid Grading of Fundus Photographs for Diabetic Retinopathy Using Crowdsourcing

Background

Screening for diabetic retinopathy is both effective and cost-effective, but rates of screening compliance remain suboptimal. As screening improves, new methods to deal with screening data may help reduce the human resource needs. Crowdsourcing has been used in many contexts to harness distributed human intelligence for the completion of small tasks including image categorization.

Objective

Our goal was to develop and validate a novel method for fundus photograph grading.

Methods

An interface for fundus photo classification was developed for the Amazon Mechanical Turk crowdsourcing platform. We posted 19 expert-graded images for grading by Turkers, with 10 repetitions per photo for an initial proof-of-concept (Phase I). Turkers were paid US $0.10 per image. In Phase II, one prototypical image from each of the four grading categories received 500 unique Turker interpretations. Fifty draws of 1-50 Turkers were then used to estimate the variance in accuracy derived from randomly drawn samples of increasing crowd size to determine the minimum number of Turkers needed to produce valid results. In Phase III, the interface was modified to attempt to improve Turker grading.

Results

Across 230 grading instances in the normal versus abnormal arm of Phase I, 187 images (81.3%) were correctly classified by Turkers. Average time to grade each image was 25 seconds, including time to review training images. With the addition of grading categories, time to grade each image increased and percentage of images graded correctly decreased. In Phase II, area under the curve (AUC) of the receiver-operator characteristic (ROC) indicated that sensitivity and specificity were maximized after 7 graders for ratings of normal versus abnormal (AUC=0.98) but was significantly reduced (AUC=0.63) when Turkers were asked to specify the level of severity. With improvements to the interface in Phase III, correctly classified images by the mean Turker grade in four-category grading increased to a maximum of 52.6% (10/19 images) from 26.3% (5/19 images). Throughout all trials, 100% sensitivity for normal versus abnormal was maintained.

Conclusions

With minimal training, the Amazon Mechanical Turk workforce can rapidly and correctly categorize fundus photos of diabetic patients as normal or abnormal, though further refinement of the methodology is needed to improve Turker ratings of the degree of retinopathy. Images were interpreted for a total cost of US $1.10 per eye. Crowdsourcing may offer a novel and inexpensive means to reduce the skilled grader burden and increase screening for diabetic retinopathy.     

Postoperative complications associated with 25-gauge pars plana vitrectomy.

BACKGROUND AND OBJECTIVE: To report postoperative complications in eyes undergoing 25-gauge pars plana vitrectomy (PPV). PATIENTS AND METHODS: Seventy consecutive eyes that underwent 25-gauge PPV for various indications, including epiretinal membrane, non-clearing vitreous hemorrhage, and idiopathic macular hole, and had a minimum follow-up of 12 weeks were reviewed retrospectively. Main outcome measures included best-corrected Snellen visual acuity, intraocular pressure (IOP), intraoperative complications, and postoperative complications. RESULTS: The mean visual acuity improved from 20/368 preoperatively to 20/105 postoperatively (P < .00005). Intraoperative complications included retinal tears in 2 eyes (2.9%). Postoperative complications included cataract progression in 17 eyes (42.5%), cystoid macular edema exacerbation in 5 eyes (7.1%), and retinal detachment in 1 eye (1.4%). Postoperative day 1 IOP was statistically lower than preoperative IOP in fluid-filled eyes (P = .031) but not in eyes filled with intravitreal air (P = .30) or gas (P = .52). Sclerotomy sutures were required intraoperatively in 5 eyes (7.1%) and postoperative day 1 hypotony was noted in 4 eyes (5.7%). All of these complications were noted in fluid-filled eyes except for one case of postoperative day 1 hypotony with gas tamponade. CONCLUSIONS: Intraoperative and postoperative complications were rare in this series of 25-gauge PPV. Postoperative cataract progression and hypotony were the most common complications. Fluid-filled eyes appear to have a higher risk of wound leakage and postoperative hypotony after 25-gauge PPV than eyes with air or gas tamponade.     

Major depression as a risk factor for chronic disease incidence: longitudinal analyses in a general population cohort

OBJECTIVE: Cross-sectional studies have consistently reported associations between major depression (MD) and chronic medical conditions. Such studies cannot clarify whether medical conditions increase the risk for MD or vice versa. The latter possibility has received relatively little attention in the literature. In this study, we evaluate the incidence of several important chronic medical conditions in people with and without MD. METHOD: The data source was the Canadian National Population Health Survey (NPHS). The NPHS included the Composite International Diagnostic Interview Short Form to assess past-year major depressive episodes. The NPHS also collected self-report data about professionally diagnosed long-term medical conditions. A longitudinal cohort was interviewed every 2 years between 1994 and 2002. Proportional hazards models were used to compare the incidence of chronic conditions in respondents with and without MD and to produce age-, sex- and covariate-adjusted estimates of the hazard ratios. RESULTS: The adjusted hazard ratios associated with MD at baseline interview were elevated for several long-term medical conditions: heart disease (1.7), arthritis (1.9), asthma (2.1), back pain (1.4), chronic bronchitis or emphysema (2.2), hypertension (1.7) and migraines (1.9). The incidences of cataracts and glaucoma, peptic ulcers and thyroid disease were not higher in respondents with MD. CONCLUSION: A set of conditions characterized particularly by pain, inflammation and/or autonomic reactivity has a higher incidence in people with MD.     

The risk of fellow eyes in patients with rhegmatogenous retinal detachment

PURPOSE OF REVIEW: A review of the current literature regarding the risk of nontraumatic rhegmatogenous retinal detachment in the fellow eye and prophylaxis of predisposing lesions is presented. RECENT FINDINGS: Although reports vary in study design and inclusion/exclusion criteria, the risk of retinal detachment in fellow eyes is similar to prior findings. Studies on prophylactic therapy also treated different cohorts. This makes drawing definitive conclusions difficult. SUMMARY: Rhegmatogenous retinal detachment poses a significant threat to the fellow eye. Risk factors specifically relevant to the fellow eye are discussed. There is insufficient evidence to recommend prophylactic therapy for prevention of retinal detachment in the fellow eye. To date, no prospective, randomized clinical trial on the prevention of retinal detachment in the fellow eye has been published.     

Dual plating for fractures of the distal third of the humeral shaft

In this study, we present a novel method for performing dual plating of extra-articular fractures of the distal third of the humerus. Since 2006, we have treated 15 such fractures with dual plates from a single posterior midline incision. In the first part of the study, we provide the surgical protocol we have used in addressing these fractures. In the second part, the charts of these patients were reviewed retrospectively to examine their clinical and radiographic outcomes. Using this technique, we have achieved an excellent union rate without significant complications while allowing early and aggressive range of motion.     

Efficacy and safety of montelukast add-on therapy in allergic rhinitis

Allergic rhinitis is a common airways hypersensitivity disease. Histamine and leukotrienes are involved in the pathogenesis of allergic rhinitis. Conventional treatments include topical steroids and antihistamines. Due to the adverse effects of these treatments, new drugs like leukotriene receptor antagonists are being investigated for the treatment of allergic rhinitis. A total of 90 patients suffering from allergic rhinitis were enrolled in this prospective, randomized, controlled study. Patients were divided randomly into three groups of 30 patients each. Group I was administered fluticasone nasal spray (200 μg in each nostril) once a day, Group II was administered fluticasone nasal spray (200 μg in each nostril) plus cetrizine (10 mg) orally once a day and Group III was administered fluticasone nasal spray (200 μg in each nostril) plus montelukast (10 mg) orally once a day. Efficacy was measured based on daytime and nighttime symptom scores. Safety was evaluated on the basis of psychomotor tests, laboratory investigations and subjective assessment. The present study showed that montelukast add-on therapy is as efficacious as conventional therapies in controlling total symptom score, but it is more efficacious in controlling nighttime symptoms. Furthermore, montelukast add-on therapy does not cause psychomotor impairment as observed with cetrizine.     

Management of nonunions of the proximal humeral diaphysis

It has been reported that the majority of nonunions of the humeral shaft evaluated are within the proximal one-third of the diaphysis. We are not aware of any reported series of humeral nonunions dealing specifically with the proximal diaphysis. We therefore sought to identify patients with a humeral shaft nonunion from an orthopaedic trauma service database, determine the frequency of those within the proximal one-third and review our treatment strategy and resulting clinical outcomes for these difficult fractures. Clinical and radiographical follow-up was available for 19 patients with a mean age of 70 years (range 29–94 years). This represented 46% of all humeral shaft nonunions treated during the study period. Dual plating was used in 11 cases to get adequate fixation in the proximal segment. Post-operative alignment was within 5° of anatomic in all cases. All nonunions healed at an average of 15.2 weeks (range 8–36 weeks). The mean length of follow-up was 12.5 months (range 6–122 months). All patients reported significant improvement in pain. The mean range of motion following fracture union was forward flexion 137°, external rotation 41° and internal rotation 30°. There were two minor complications and neither required a secondary surgery. The surgical technique we have used emphasising a thorough debridement of the nonunion site, correction of the deformity, fracture site compression with a rigid construct and bone grafting provides excellent rates of union and clinical outcomes.