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Purpose: A number of algorithms have been developed to calculate screening intervals for diabetic retinopathy on the basis of individual risk factors. However, these approaches have not considered proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DME) as separate end points and death as competing risk. Methods: A multi‐state survival model with death as competing risk was used to predict the screening interval for diabetic retinopathy based on information about all 2446 patients from a well‐defined population who had started treatment for either PDR or DME during 25 years. The performance of the model was tested on the existing database and at seven screening sites on patients who had not developed a treatment requiring condition. Results: Testing on the existing database showed that at a risk level of 2% the algorithm could predict a screening interval with a success rate higher than 90% and a 1.75 times average prolongation of the screening interval without failing to detect the development of verified PDR og DME. The model was limited to a diabetes duration shorter than 40 years and depended on knowledge of relevant risk factors. At the other participating screening sites the algorithm predicted shorter intervals than the screener. Conclusions: Algorithms for individualised screening for diabetic retinopathy can prolong screening intervals without losing patients who develop a vision threatening condition. The calculation of screening intervals requires access to relevant risk factors and should be developed on large data sets that reflect the population in which the algorithm should be used. [ABSTRACT FROM AUTHOR]

Purpose: To investigate diabetic retinopathy (DR) as a potential marker of cardiovascular disease (CVD) in adults with type 1 diabetes attending the Danish DR‐screening programme and non‐diabetes adults. Methods: In this registry‐based matched case–cohort study, we identified 16 547 adults with type 1 diabetes, who were registered in the Danish Registry of Diabetic Retinopathy (DiaBase). Each case was age‐ and sex‐matched by five non‐diabetes individuals (n = 82 399), and odds ratios (ORs) and hazard ratios (HRs) were estimated for incident and upcoming CVD in multivariable models. Results: Adults with type 1 diabetes (median age 44.5 years, 57.6% male) were more likely to have prevalent CVD (OR 1.29; 95% CI, 1.20–1.38) and to develop CVD within 5 years (HR 1.19; 95% CI, 1.08–1.30) as compared to non‐diabetes control. However, adults without DR were less likely to develop CVD (HR 0.84; 95% CI, 0.72–0.97) compared to the reference population. For adults with type 1 diabetes, there was an increasing risk for incident CVD for increasing levels of DR (HR 1.33, 1.95, 1.71 and 2.39 for DR‐levels 1–4, respectively). Patients with CVD at the time of the first screening had a higher risk to develop DR during follow‐up (HR 1.23; 95% CI, 1.02–1.49). Conclusion: In a nationwide matched case–cohort study adjusted for potential confounders, DR was identified as an independent marker of prevalent and incident CVD in type 1 diabetes with increasing risk demonstrated for higher levels of DR. Likewise, CVD also independently predicted the risk of incident DR. [ABSTRACT FROM AUTHOR]

To estimate the prevalence of convergence insufficiency (CI) in adult patients with post-concussion syndrome and determine the impact of CI on symptom load. Cross-sectional study of 103 patients with neurological symptoms 2–6 months after a concussion. Symptoms were assessed with the Rivermead Post Concussion Symptoms Questionnaire (RPQ), and CI was diagnosed using near point of convergence, vergence facility, and the Convergence Insufficiency Symptom Survey. The RPQ score for patients with and without CI was compared, and sensitivity, specificity, and area under the receiver operating characteristic curve for the two visually related RPQ questions as indicators of CI were calculated. The proportion of patients diagnosed with symptomatic CI was 20.4% (95% confidence interval: 13.1–29.5%). The RPQ score was significantly higher for patients with symptomatic CI both before (p =.01) and after removal of the two visually related questions in the RPQ-questionnaire (p =.03). The two visually related RPQ questions were unable to detect CI. In patients with post-concussion syndrome, the load of nonvisual symptoms is higher in the presence of CI. A prospective interventional study on CI is required to study the relationship between CI and other post-concussion symptoms. [ABSTRACT FROM AUTHOR]

Purpose: The retina contains a number of vasoactive neuropeptides and corresponding receptors, but the role of these neuropeptides for tone regulation of retinal arterioles has not been studied in detail. Methods: Porcine arterioles with preserved perivascular retinal tissue were mounted in a wire myograph, and the tone was measured after the addition of increasing concentrations of bradykinin, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), substance P (SP), calcitonin gene‐related peptide (CGRP) and brain natriuretic peptide (BNP). The experiments were performed during inhibition of the synthesis of nitric oxide (NO), prostaglandins and dopamine and were repeated after removal of the perivascular retinal tissue. Results: Bradykinin, VIP and CGRP induced significant concentration‐dependent dilatation and NPY significant concentration‐dependent contraction of the arterioles in the presence of perivascular retinal tissue (p < 0.03 for all comparisons) but not on isolated arterioles. BNP and SP had no effect on vascular tone. The NOS inhibitor L‐NAME reduced bradykinin‐ and VIP‐induced relaxation (p < 0.001 for both comparisons), whereas none of the other inhibitors influenced the vasoactive effects of the studied neuropeptides. Conclusion: The effects of neuropeptides on the tone of retinal arterioles depend on the perivascular retinal tissue and may involve effects other than those mediated by nitric oxide, prostaglandins and adrenergic compounds. Investigation of the mechanisms underlying the vasoactive effect of neuropeptides may be important for understanding and treating retinal diseases where disturbances in retinal flow regulation are involved in the disease pathogenesis. [ABSTRACT FROM AUTHOR]

A study conducted in Denmark evaluated the risk of progression from no diabetic retinopathy (DR) to proliferative diabetic retinopathy (PDR) in individuals with diabetes. The study found that the risk of progression to PDR within 2 years was lower than expected in a national cohort. While individuals with impaired glycemic control had a higher risk of progression to PDR, this was only statistically significant in those with type 2 diabetes. The study suggests that biannual screening intervals for individuals without DR may be safely introduced in national DR screening programs. The study was supported by VELUX FONDEN. [Extracted from the article]