Iris Color and Day-Night Changes in the Sympathovagal Ratio

Completed

• Conditions: Iris Diseases
• Interventions: Other: Iris Color Measurement , LF/HF Measurement

• Registration Number: NCT05759715
• Lead Sponsor: Ankara Ataturk Sanatorium Training and Research Hospital

Brief Summary

Iris melanocytes are innervated by parasympathetic and sympathetic nerve endings. Light affects autonomic nervous system activity via the retino-hypothalamic pathway. The hypothesis that the day-to-night variations in the sympatovagal ratio (LF/HF) may differ among individuals with different brown iris patterns was tested.

Detailed Description

A total of 621 healthy adults, aged between 16 and 50, with brown eyes and not diagnosed with a disease that might affect the autonomous nerve system were included in the study. A digital camera was used to acquire iris photos. Subjects were grouped into iris color groups (2-0 bg, 1-0 bg, 1-1 db, 1-1 lb, 2-0 b, and 1-0 b). Iris photos were analyzed with Picture Color Analyzer RBG software. The Central/Peripheral (R/RGB) ratio was used for objective distinction between the groups. Using 24-h Holter ECG monitoring, the change in the sympathovagal ratio from day (between 07:00 and 23:00 hrs) to night (between 23:00 and 07:00 hrs) was determined with the formula \[(Day - Night) LF/HF)/Day LF/HF\].

Study Timeline

• Study Start: 2016-05-05
• Primary Completion: 2022-05-05
• Study Completion: 2022-06
• Study First Submitted: 2023-02-27
• Study First Submitted QC: 2023-02-27
• Status Verified: 2023-03
• Last Update Submitted: 2023-03-07
• Study First Posted: 2023-03-08
• Last Update Posted: 2023-03-09

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 621

Inclusion Criteria

A total of 650 healthy individuals between the ages of 16 and 50 .

Exclusion Criteria

Diseases that could affect the autonomic nervous system; Obesity Obstructive sleep apnea syndrome Hypertension Diabetes mellitus Atrial fibrillation Coronary disease Heart failure Goiter, etc.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
1-0 lightbrown-green (1-0 bg).	Iris Color Measurement , LF/HF Measurement	Those with slightly dark brown in the central area and green in the peripheral area,
dark brown (1-1 db)	Iris Color Measurement , LF/HF Measurement	Eyes with the same color structure in the central iris and the peripheral iris.
2-0 darkbown-green (2-0 bg)	Iris Color Measurement , LF/HF Measurement	Those with distinctively dark brown in the central area, slightly green in the peripheral area,
slightly dark brown (1-0 b)	Iris Color Measurement , LF/HF Measurement	Those with slightly dark brown (1-0 b) in the central iris area compared to the periphery .
light brown (1-1 lb)	Iris Color Measurement , LF/HF Measurement	Eyes with the same color structure in the central iris and the peripheral iris.
dark brown (2-0 b)	Iris Color Measurement , LF/HF Measurement	Those with distinctively dark brown in the central iris area compared to the periphery .

Primary Outcome Measures

Name	Time	Method
LF/HF ratio	one week	low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, 0.16-0.4 Hz) measurements were taken from day and night changes in the heart rate by using the frequency-domain analysis method.