What is the prevalence of diabetic macular oedema involving the centre of the macula in patients undergoing digital diabetic retinopathy screening

Free Paper Sessions Design. Retrospective analysis. Purpose. To assess the prevalence of center-involving diabetic macular oedema (CIDMO) and risk factors. Methods. Retrospective review of patients who were screen positive for maculopathy (M1) during 2010 in East and North Birmingham. The CIDMO was diagnosed by qualitative identification of definite foveal oedema on optical coherence tomography (OCT). Results. Out of a total of 15,234 patients screened, 1194 (7.8%) were screen positive for M1 (64% bilateral). A total of 137 (11.5% of M1s) were diagnosed with macular oedema after clinical assessment. The OCT results were available for 123/137; 69 (56.1%) of these had CI-DMO (30 bilateral) which is 0.5% of total screens and 5.8% of those screen positive for M1. In those with CIDMO 60.9% were male and 63.8% Caucasian; 90% had type 2 diabetes and mean diabetes duration was 20 years (SD 9.7, range 2-48). Mean HbA1c was 8.34%±1.69, with 25% having an HbA1c =9%. Furthermore, 62% were on insulin, 67% were on antihypertensive therapy, and 64% were on a cholesterol-lowering drug. A total of 37.7% had an eGFR between 30% and 60% and 5.8% had eGFR <30. The only significant difference between the CIDMO and non-CIDMO group was mean age (67.83±12.26 vs 59.69±15.82; p=0.002). A total of 65.2% of those with CIDMO also had proliferative or preproliferative retinopathy in the worst eye and 68.1% had subsequently been treated with macular laser at the time of data review. Conclusions. The results show that the prevalence of CIDMO in our diabetic population was 0.5%. A significant proportion of macula oedema patients were found to have type 2 diabetes with long disease duration, suboptimal glycemic and hypertensive control, and low eGFR. The data support that medical and diabetic review of CIDMO patients is warranted particularly in the substantial number with poor glycemic control and if intravitreal therapies are indicated.

Factors associated with degeneration of the thallus centre in foliose lichens

Degeneration of the older parts of foliose lichen thalli often lead to the formation of a space or 'window' in the centre of the colonies. The percentage of thalli of different size which exhibited 'windows' was studied in twenty saxicolous lichen populations in south Gwynedd, Wales. The proportion of thalli with 'windows' increased with thallus size. The size class at which 50% and 100% of thalli exhibited 'windows' varied between populations. Differences between populations were not correlated with distance from the sea, aspect, slope or porosity of the substrate or the total number of lichen species present. However, a higher percentage of smaller thalli had 'windows' on rock surfaces with a greater lichen cover. There were no significant differences in the levels of Ca, Mg, Cu or Zn in large (>4 cm) and small (<2 cm) Parmelia conspersa (Ehrh. ex Ach.) Ach. thalli or in the centres and marginal lobes of these thalli. The concentration of ribitol, arabitol and mannitol was significantly reduced in the centre of large thalli compared with the margin of large thalli and the centre of small thalli. However, carbohydrate levels were similar in the centre of large thalli and the margin of small thalli. The data suggest that loss of the thallus centre is a degenerative process related to thallus size. In the field, the formation of 'windows' may be related to the intensity of competition on a substrate. Central degeneration was not associated with a deficiency or an accumulation of Ca, Mg, Cu and Zn in the thallus centre. However, degeneration may be associated with a reduction in carbohydrates in the centre compared with the marginal lobes.

Improving the cost-effectiveness of photographic screening for diabetic macular oedema:a prospective, multi-centre, UK study

Background/aims: Retinal screening programmes in England and Scotland have similar photographic grading schemes for background (non-proliferative) and proliferative diabetic retinopathy, but diverge over maculopathy. We looked for the most cost-effective method of identifying diabetic macular oedema from retinal photographs including the role of automated grading and optical coherence tomography, a technology that directly visualises oedema. Methods: Patients from seven UK centres were recruited. The following features in at least one eye were required for enrolment: microaneurysms/dot haemorrhages or blot haemorrhages within one disc diameter, or exudates within one or two disc diameters of the centre of the macula. Subjects had optical coherence tomography and digital photography. Manual and automated grading schemes were evaluated. Costs and QALYs were modelled using microsimulation techniques. Results: 3540 patients were recruited, 3170 were analysed. For diabetic macular oedema, England's scheme had a sensitivity of 72.6% and specificity of 66.8%; Scotland 's had a sensitivity of 59.5% and specificity of 79.0%. When applying a ceiling ratio of £30 000 per quality adjusted life years (QALY) gained, Scotland's scheme was preferred. Assuming automated grading could be implemented without increasing grading costs, automation produced a greater number of QALYS for a lower cost than England's scheme, but was not cost effective, at the study's operating point, compared with Scotland's. The addition of optical coherence tomography, to each scheme, resulted in cost savings without reducing health benefits. Conclusions: Retinal screening programmes in the UK should reconsider the screening pathway to make best use of existing and new technologies.