The advent in Online Social Networks (OSN) and Internet of Things (IoT) has created a new world of collaboration and communication between people and devices. The domain of internet of things uses billions of devices (ranging from tiny sensors to macro scale devices) that continuously produce and exchange huge amounts of data with people and applications. Similarly, more than a billion people are connected through social networking sites to collaborate and share their knowledge. The applications of IoT such as smart health, smart city, social networking, video surveillance and vehicular communication are quickly evolving people’s daily lives. These applications provide accurate, information-rich and personalized services to the users. However, providing personalized information comes at the cost of accessing private information of users such as their location, social relationship details, health information and daily activities. When the information is accessible online, there is always a chance that it can be used maliciously by unauthorized entities. Therefore, an effective access control mechanism must be employed to ensure the security and privacy of entities using OSN and IoT services. Access control refers to a process which can restrict user’s access to data and resources. It enforces access rules to grant authorized users an access to resources and prevent others. This survey examines the increasing literature on access control for traditional models in general, and for OSN and IoT in specific. Challenges and problems related to access control mechanisms are explored to facilitate the adoption of access control solutions in OSN and IoT scenarios. The survey provides a review of the requirements for access control enforcement, discusses several security issues in access control, and elaborates underlying principles and limitations of famous access control models. We evaluate the feasibility of current access control models for OSN and IoT and provide the future development direction of access control for the same.

Purpose: To investigate the frequency of primary versus secondary eye removal, frequency of enucleation versus evisceration, and characteristics and outcomes of patients undergoing these procedures after presenting with severe ocular trauma. Patients and Methods: Retrospective chart review of patients presenting to the emergency department (ED) with severe eye trauma necessitating enucleation or evisceration between 2010 and 2018. Results: There were 92 eyes from 90 patients included in our study. Twenty-seven percent of eyes underwent primary removal (n=25, 14 enucleation, 11 evisceration), while 73% of eyes underwent secondary removal (n=67, 50 enucleation, 17 evisceration). The mean patient age was 45.2 years (range 4.2– 92.6); primary enucleation/evisceration patients were older on average than secondary eye removal patients [53.8 years (range 15.9– 91.2) versus 42.2 years (range 4.2– 91.6 years), p=0.04]. A median of 34 days passed between ED presentation and secondary enucleation/evisceration. Before undergoing secondary enucleation/evisceration, patients underwent a median of one ocular procedure (range 0– 14) for various complications of trauma including orbital infection, choroidal or retinal tear or detachment, and wound dehiscence. Open globe injury repairs comprised 43 of the 92 total procedures (47%) performed prior to secondary enucleation/evisceration. Secondary enucleations/eviscerations required a median of seven clinic visits compared to two clinic visits required after primary surgeries (p< 0.01). 10.7% of all patients (n=10) had at least one implant-related complication following enucleation/evisceration, with all but one of these patients being in the secondary enucleation/evisceration group. Conclusion: Primary enucleation or evisceration was performed in 27% of all eye removals, and enucleation was performed in 69.6% of all eye removals. Future research is warranted to determine if primary eye removal may be appropriate and when to consider enucleation versus evisceration.

Background/aims Markers to clinically evaluate structural changes from diabetic retinal neurodegeneration (DRN) have not yet been established. To study the potential role of peripapillary retinal nerve fibre layer (pRNFL) thickness as a marker for DRN, we evaluated the relationship between diabetes, as well as glycaemic control irrespective of diabetes status and pRNFL thickness. Methods Leveraging data from a population-based cohort, we used general linear mixed models (GLMMs) with a random intercept for patient and eye to assess the association between pRNFL thickness (measured using GDx) and demographic, systemic and ocular parameters after adjusting for typical scan score. GLMMs were also used to determine: (1) the relationship between: (A) glycated haemoglobin (HbA1c) irrespective of diabetes diagnosis and pRNFL thickness, (B) diabetes and pRNFL thickness and (2) which quadrants of pRNFL may be affected in participants with diabetes and in relation to HbA1c. Results 7076 participants were included. After controlling for covariates, inferior pRNFL thickness was 0.94 µm lower (95% CI −1.28 µm to −0.60 µm), superior pRNFL thickness was 0.83 µm lower (95% CI −1.17 µm to −0.49 µm) and temporal pRNFL thickness was 1.33 µm higher (95% CI 0.99 µm to 1.67 µm) per unit increase in HbA1c. Nasal pRNFL thickness was not significantly associated with HbA1c (p=0.23). Similar trends were noted when diabetes was used as the predictor. Conclusion Superior and inferior pRNFL was significantly thinner among those with higher HbA1c levels and/or diabetes, representing areas of the pRNFL that may be most affected by diabetes.

Purpose: We aimed to determine long-term visual and anatomical outcomes among patients with center involving-diabetic macular edema and good vision and evaluate factors associated with visual and anatomic outcomes. Materials and Methods: In this retrospective study, all patients with type 2 diabetes aged ≥18 years seen at the Wilmer Eye Institute between March 2015-June 2018 and with diabetic macular edema confirmed on spectral domain optical coherence tomography imaging were included, provided they had visual acuity of 20/30 or better in ≥1 eye and a follow-up duration of ≥3 clinic visits. Change in logMAR visual acuity and central 1 mm foveal thickness from baseline, lines of visual acuity gained/lost for overall cohort stratified by treatment were analyzed. Results: Among 197 (243 eyes) participants, mean (± standard deviation) age was 63.4 ± 11.2 years, and half were males. Average duration of follow-up was 1.7 ± 0.7 years. 146 eyes (60%) received anti-vascular endothelial growth factor injections, at an average of 3.7 ± 2.9 injections/eye/year. Mean logMAR visual acuity at baseline was 0.1 ± 0.1 [Snellen 20/25] in both treatment and observation (no anti-vascular endothelial growth factor treatment received during and 3 months prior to the study inclusion period) groups. Final logMAR visual acuity was 0.2 ± 0.2 in treatment group [Snellen 20/32] versus 0.1 ± 0.3 in observation group [Snellen 20/25]; (p=0.23). Mean central foveal thickness changed from 333 ± 66 to 308 ± 45 microns in treatment group and 319 ± 41 to 308 ± 65 microns in observation group. Conclusions: After an average of 1.7 years of follow-up, there were no significant differences in final vision or central foveal thickness irrespective of whether patients received or did not receive treatment with anti-vascular endothelial growth factor injections.