Colour Vision Impairment During Acute Hypobaric Hypoxia

Study Overview
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Brief Summary
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This study analyses the impairment of colour vision during hypobaric hypoxia in volunteers of different groups.

Detailed Description
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This study analyses the impairment of colour vision during hypobaric hypoxia in volunteers of different groups. Five different Groups were analysed: ground control binocular (n=12, Bi/GC) ground control monocular (n=11, Mo/GC) 10,000 ft, 60 min, monocular (n=10, Mo/60/10,000) 15,000 ft, 15 min, binocular (n=11, Bi/15/15,000) 15,000 ft, 60 min, monocular (n=10, Mo/60/15,000)

Official Title
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Randomized Controlled Trial for Evaluation of Colour Vision Impairment During Acute Hypobaric Hypoxia in Aviation Medicine

Conditions
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Hypoxia, Altitude

Intervention / Treatment
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* Other: Hypobaric Hypoxia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: volunteers from 18 years old Exclusion Criteria: cardiovascular, pulmonary, neurological, or ear, nose, and throat disease pregnant or suffering from cold symptoms

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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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Five different Groups were analyzed: ground control binocular (n=12, Bi/GC) ground control monocular (n=11, Mo/GC) 10,000 ft, 60 min, monocular (n=10, Mo/60/10,000) 15,000 ft, 15 min, binocular (n=11, Bi/15/15,000) 15,000 ft, 60 min, monocular (n=10, Mo/60/15,000)
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: ground control binocular<br>Intervention: pressure chamber environment Procedures: Colour vision tests were performed under normoxia with both eyes three times in a row for appropriate comparability to the simulated flight stages pre-peri-post hypoxia in the intervention groups | |
| No Intervention: ground control monocular<br>Intervention: pressure chamber environment Procedures: Colour vision tests were performed under normoxia with one eye at a time three times in a row for appropriate comparability to the simulated flight stages pre-peri-post hypoxia in the intervention groups | |
| Experimental: 10,000 ft, 60 min, monocular pre-peri-post<br>Intervention: Hypoxia equivalent to an altitude of 10.000 ft. for 60 minutes Procedures: Colour vision tests were performed with one eye at a time, thereby: pre intervention with no hypoxia administered during intervention with hypoxia equivalent to an altitude of 10.000 ft. for 60 minutes post intervention with no hypoxia administered | Other: Hypobaric Hypoxia<br>* The Waggoner Computerized Color Vision Test (WCCVT) and the Waggoner D-15 (WC-D15) were performed by 54 healthy volunteers in a decompression chamber.<br>|
| Experimental: 15,000 ft, 15 min, binocular<br>Intervention: Hypoxia equivalent to an altitude of 15.000 ft. for 15 minutes Procedures: Colour vision tests were performed with both eyes, thereby: pre intervention with no hypoxia administered during intervention with hypoxia equivalent to an altitude of 15000 ft. for 15 minutes post intervention with no hypoxia administered | Other: Hypobaric Hypoxia<br>* The Waggoner Computerized Color Vision Test (WCCVT) and the Waggoner D-15 (WC-D15) were performed by 54 healthy volunteers in a decompression chamber.<br>|
| Experimental: 15,000 ft, 60 min, monocular<br>Intervention: Hypoxia equivalent to an altitude of 15.000 ft. for 60 minutes Procedures: Colour vision tests were performed with one eye at a time, thereby: pre intervention with no hypoxia administered during intervention with hypoxia equivalent to an altitude of 15.000 ft. for 60 minutes post intervention with no hypoxia administered | Other: Hypobaric Hypoxia<br>* The Waggoner Computerized Color Vision Test (WCCVT) and the Waggoner D-15 (WC-D15) were performed by 54 healthy volunteers in a decompression chamber.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Colour vision pre hypoxia monocular/binocular Waggoner CCVT | Waggoner CCVT was administered in the pressure chamber pre hypoxia intervention, thereby the following parameters were collected: - the number of correctly identified plates in the Waggoner CCVT as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: - depending on the time the subjects took for the colour vision tests, the time between the end of the pre-test and the onset of hypoxia was slightly variable | Assessment was conducted 15 minutes before the start of the hypoxia intervention and the number of correctly identified plates in the Waggoner CCVT was collected | 
| Colour vision pre hypoxia monocular/binocular D15 | Waggoner D15 was administered in the pressure chamber pre hypoxia intervention, thereby the following parameters were collected: - S-Index, C-Index and TES in the Waggoner D15 as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: depending on the time the subjects took for the colour vision tests, the time between the end of the pre-test and the onset of hypoxia was slightly variable | Assessment was conducted 15 minutes before the start of the hypoxia intervention and S-Index, C-Index and TES in the Waggoner D15 were collected | 
| Colour vision during hypoxia monocular/binocular Waggoner CCVT | Waggoner CCVT was administered in the pressure chamber during hypoxia intervention, thereby the following parameters were collected: - the number of correctly identified plates in the Waggoner CCVT as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: as of the study arm 15,000 ft, 15 min, binocular assessment was conducted immediately after onset of hypoxia as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular assessment was conducted 45 minutes after onset of hypoxia depending on the time the subjects took for the colour vision tests, the time between the end of the peri-test and the end of hypoxia was slightly variable | Assessment was conducted immediately or 45 minutes after induction of hypoxia and the number of correctly identified plates in the Waggoner CCVT was collected | 
| Colour vision during hypoxia monocular/binocular D15 | Waggoner D15 was administered in the pressure chamber during hypoxia intervention, thereby the following parameters were collected: - S-Index, C-Index and TES in the Waggoner D15 as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: as of the study arm 15,000 ft, 15 min, binocular assessment was conducted immediately after onset of hypoxia as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular assessment was conducted 45 minutes after onset of hypoxia depending on the time the subjects took for the colour vision tests, the time between the end of the peri-test and the end of hypoxia was slightly variable | Assessment was conducted immediately or 45 minutes after induction of hypoxia and S-Index, C-Index and TES in the Waggoner D15 were collected | 
| Colour vision after hypoxia monocular/binocular Waggoner CCVT | Waggoner CCVT was administered in the pressure chamber post hypoxia intervention, thereby the following parameters were collected: - the number of correctly identified plates in the Waggoner CCVT as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: as of the study arm 15,000 ft, 15 min, binocular assessment was conducted immediately after 15min of hypoxia as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular assessment was conducted immediately after 60 minutes of hypoxia | Assessment was conducted immediately after hypoxia and the number of correctly identified plates in the Waggoner CCVT was collected | 
| Colour vision after hypoxia monocular/binocular D15 | Waggoner D15 was administered in the pressure chamber post hypoxia intervention, thereby the following parameters were collected: - S-Index, C-Index and TES in the Waggoner D15 as of the study arm 15,000 ft, 15 min, binocular the colour vision tests were performed binocularly as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular the colour vision tests were performed monocularly Time Frame - additional info: as of the study arm 15,000 ft, 15 min, binocular assessment was conducted immediately after 15min of hypoxia as of the study arms 15,000 ft, 60 min, monocular and 10,000 ft, 60 min, monocular assessment was conducted immediately after 60 minutes of hypoxia | Assessment was conducted immediately after hypoxia and S-Index, C-Index and TES in the Waggoner D15 were collected | 
| Colour vision without hypoxia monocular/binocular Waggoner CCVT | Waggoner CCVT was administered three times in a row without hypoxia, thereby the following parameters were collected: - the number of correctly identified plates in the Waggoner CCVT as of the study arm ground control binocular the colour vision tests were performed binocularly as of the study arm ground control monocular the colour vision tests were performed monocularly Time Frame - additional info: - depending on the time the subjects took for each of the colour vision tests, total duration of all 3 test sequences can differ slightly | Assessment was coducted independently of hypoxia three times in a row with a 1 minute break in between each test and the number of correctly identified plates in the Waggoner CCVT was collected | 
| Colour vision without hypoxia monocular/binocular D15 | Waggoner D15 was administered three times in a row without hypoxia, thereby the following parameters were collected: - S-Index, C-Index and TES in the Waggoner D15 as of the study arm ground control binocular the colour vision tests were performed binocularly as of the study arm ground control monocular the colour vision tests were performed monocularly Time Frame - additional info: - depending on the time the subjects took for each of the colour vision tests, total duration of all 3 test sequences can differ slightly | Assessment was coducted independently of hypoxia three times in a row with a 1 minute break in between each test, and S-Index, C-Index and TES in the Waggoner D15 were collected |