Diabetic Retinopathy: Effects of Melatonin Treatment on Visual Functions and Circadian Rhythm

Study Overview
=================
Brief Summary
-----------------
This study evaluates the effect of melatonin 4 mg on circadian rhythm and visual function of patients with diabetes mellitus. Half of the patients will receive melatonin (arm-1) and the other half will receive placebo (arm-2), both groups in 3 weeks. After a week of washout, the patients will cross over to the other treatment arm.

Official Title
-----------------
Diabetic Retinopathy: Effects of Melatonin Treatment on Visual Functions and Circadian Rhythm

Conditions
-----------------
Diabetic Retinopathy, Melatonin, Circadian Dysrhythmia, Circadian Rhythm Sleep Disorder, Unspecified Type

Intervention / Treatment
-----------------
* Drug: Melatonin 4 mg Tablet


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Diabetic patients Age range 40-75 years Participant should be legally competent Exclusion Criteria: Other known eye disease. Eye disease manifestation during ocular examination. Competing neurologic and systemic conditions affecting retina. Use of any drugs influencing pupillary light reflex and sleep pattern. Refractive error with need of > 6 diopter lenses. Pregnancy Alcohol consumption during the trial Lack of cooperation Allergy to melatonin and/or preservatives in melatonin and placebo Reduced hepatic function Fluvoxamin intake due to drug interaction Consumption of Alpha-1 and beta-1 adnergic antagoists. Alcohol consumption during treatment

Ages Eligible for Study
-----------------
Minimum Age: 40 Years
Maximum Age: 75 Years

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

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

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

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: A Double-blind, randomized, placebo-controlled trial
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Arm 1<br>Melatonin, 1 tablet (4 mg), every evening 2 hours before bed in 21 days. | Drug: Melatonin 4 mg Tablet<br>* Participants are randomized into arm 1 or arm2, recieving melatonin or placebo, respectively, for 21 days, followed by 1 week of washout, and then swichting to the contralateral treatment arm.<br>|
| Placebo Comparator: Arm 2<br>Place, 1 tablet (4 mg), every evening 2 hours before bed in 21 days. | Drug: Melatonin 4 mg Tablet<br>* Participants are randomized into arm 1 or arm2, recieving melatonin or placebo, respectively, for 21 days, followed by 1 week of washout, and then swichting to the contralateral treatment arm.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Progression of diabetic retinopathy, oscillary potential | Progression of diabetic retinopati measured with electroretinography | 3 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-illumination pupillary light response | Melanopsin-mediated pupillary response | 3 weeks | 
| Circadian photoentrainment | Salivary melatonin level and sleep assessment | 3 weeks | 
| Retinal structure | Retinal structure assessed by optical coherence tomography | 3 weeks |