Diabetes Visual Function Supplement Study

Study Overview
=================
Brief Summary
-----------------
This study will evaluate the effects of a novel multi-component dietary supplement on the visual function and retinal structure of patients with diabetes with both no diabetic retinopathy and mild to moderate diabetic retinopathy. This is a placebo-controlled trial and neither subjects nor examiners will know if any given subject is taking active supplement or placebo. The hypothesis is that the supplement will improve visual function and retinal structure in subjects on active supplement

Detailed Description
-----------------
Adult patients with either type 1 or type 2 diabetes will be enrolled with baseline measurement of visual acuity, contrast sensitivity, color vision, threshold macular perimetry, macular pigment optical density, optical coherence tomography, glycosylated hemoglobin, blood lipids and serum vitamin D status. A multi-component dietary supplement containing ingredients currently available over the counter in the US will be taken for six months and repeat measurements of the above parameters obtained.

Official Title
-----------------
Effects of a Novel Dietary Supplement on Visual Function in Patients With Diabetes With and Without Early Diabetic Retinopathy

Conditions
-----------------
Diabetes Mellitus - Type 1, Diabetes Mellitus - Type 2, Non-proliferative Diabetic Retinopathy

Intervention / Treatment
-----------------
* Dietary Supplement: multi-component nutritional supplement capsules
* Dietary Supplement: multi-component dietary supplement


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: diabetes mellitus diagnosed at least 5 years age greater than or equal to 18 years English speaker Exclusion Criteria: proliferative diabetic retinopathy or severe non-proliferative retinopathy clinically significant macular edema corrected visual acuity less than 20/30 in either eye diagnosis of other serious eye disease (glaucoma, age-related maculopathy) less than 18 years old non-English speaker no known allergy or sensitivity to any supplement ingredients

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: supplement - no retinopathy<br>subjects receiving active supplement and with no retinopathy based on clinical examination | Dietary Supplement: multi-component nutritional supplement capsules<br>* two capsules containing nutritional supplements per day for 6 months (vitamin C, mixed tocopherols/tocotrienols, vitamin D, fish oil, lutein, zeaxanthin, pine bark extract, benfotiamine, green tea extract, curcumin)<br>|
| Placebo Comparator: placebo - no retinopathy<br>patients receiving placebo and who have no diabetic retinopathy based on clinical examination | Dietary Supplement: multi-component dietary supplement<br>* placebo capsules<br>* Other names: two placebo capsules per day for six months;|
| Experimental: supplement - retinopathy<br>patients receiving the active supplement and who have mild to moderate non-proliferative diabetic retinopathy based on clinical examination | Dietary Supplement: multi-component nutritional supplement capsules<br>* two capsules containing nutritional supplements per day for 6 months (vitamin C, mixed tocopherols/tocotrienols, vitamin D, fish oil, lutein, zeaxanthin, pine bark extract, benfotiamine, green tea extract, curcumin)<br>|
| Placebo Comparator: placebo - retinopathy<br>patients receiving placebo and who have mild to moderate non-proliferative diabetic retinopathy based on clinical examination | Dietary Supplement: multi-component dietary supplement<br>* placebo capsules<br>* Other names: two placebo capsules per day for six months;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in visual function | Change in contrast sensitivity, color vision and macular perimetry thresholds | At baseline and again at six months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in serum markers | Changes in glycosylated hemoglobin, serum lipids, serum vitamin D (all subjects) and the serum inflammatory cytokine, tumor necrosis factor-alpha (subjects with retinopathy) | At baseline and again at six months | 
| Changes in retinal structure | Changes in optical coherence tomography and macular pigment optical density | At baseline and again at 6 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
diabetes, diabetic retinopathy, nutritional supplements, visual function, macular pigment, macular threshold sensitivity, contrast sensitivity, color vision, optical coherence tomography