A Systematic Study of Retinal Structure and Function in Diabetic Macular Oedema

Study Overview
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Brief Summary
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Diabetic retinopathy(DR) is a sight threatening condition that occurs in persons with diabetes. DR arises as a consequence of damage to the retinal blood vessels and is related to the high and fluctuating sugar levels in the blood stream. An eye with DR will have abnormal appearing retinal blood vessels which become engorged and dilated, leaky and fragile or undergo closure. The net result is a picture of haemorrhage and or ischaemia (lack of blood supply). A particular feature of DR is the accumulation of fluid in the macula which is the central part of the retina and responsible for detailed eye sight. This peculiar form of DR is called Diabetic Macular Oedema (DMO). DMO can occur in isolation without other features of DR. DMO is commoner in type 2 diabetes where insulin resistance and abnormalities of blood fats are found. The investigators wish to study DR and DMO using high resolution retinal imaging and functional tests in normal participants, those participants with diabetes without any overt signs of disease and those with DR and DMO in order to understand how the condition develops and whether there are any unique risk factors that can be identified

Official Title
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A Systematic Study of Retinal Structure and Function in Diabetic Macular Oedema

Conditions
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Diabetes Mellitus, Diabetic Retinopathy, Diabetic Macular Edema

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Group 1 (Healthy controls without DM): Persons older than 18 years without DM Fundus free of any signs of retinal disease Best Corrected Visual Acuity of 20/40 (73 ETDRS letters) in both eyes Group 2 (Persons with DM with no retinopathy): Persons with Type 1 or type 2 diabetes older than 18 years Normal fundus, Absence of features of DR or DMO in both eyes Best Corrected Visual Acuity 20/40 (73 ETDRS letters) in at least one eye Group 3: Persons with Type 1 or type 2 diabetes 18 years and older Fundus signs of mild, moderate or severe DR and or DMO Best Corrected Visual Acuity 20/200 (33 ETDRS letters) or better Exclusion Criteria: Recent ocular surgical procedures performed within the previous 3 months Presence of ocular confounding disorders such as neovascular age related macular degeneration, glaucoma or active uveitis Serious life threatening conditions that would preclude attendance in the longitudinal part of the study Neurological conditions that can impair vision

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cases<br>Persons with type 1 or type 2 DM with features of DR and or DMO ranging from extremely mild to severe. | |
| Control definition<br>Persons with a history of type 1 or type 2 DM without any clinical features of DR or DMO in either eye or persons without a history of DM and without retinal disease in either eye. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Presence of DMO evaluated from the optical coherence tomography (OCT) images |  | The outcome measures will be assessed at the end of 3 months |