RELEVANCE OF VISUAL ACCOMMODATION FOR PERFORMANCE IN SPACECRAFT

"DARK FOCUS" IS DEFINED AS THE RESTING STATE OF VISUAL ACCOMMODATION YET TWO GENERAL MISCONCEPTIONS EXIST. FIRST, THAT THE RESTING POINT IS AT OPTICAL INFINITY, AND SECONDLY,THAT THE EYE ACCOMMODATES ACCURATELY. VISUAL PERFORMANCES REQUIRED IN SPACE ENTAIL CONTINUOUSLY CHANGING VIEWING DISTANCES AND TO ALLOW CREW MEMBERS TO PERFORM ROUTINELY ACCOMMODATION CHANGES NEED TO BE ASSESSED. WHEN A PERSON IS FOCUSED AT OTHER THAN THE TARGET DISTANCE, SEEING CAN BE DEGRADED. CONDITIONS IN SPACECRAFT (SPACE ADAPTATION SYNDROME, PROTRACTED CONFINEMENT) CAN BE STRESSFUL, THUS COULD INFLUENCE AUTONOMIC NERVOUS SYSTEM ACTIVITY. WE PROPOSE TO DEVELOP AN ACCURATE, RELIABLE, AND PORTABLE TEST OF ACCOMMODATION WHICH IS SPATIALLY AND TEMPORALLY CONCISE IN ORDER TO BE USED ABOARD SPACECRAFT. IN PHASE I WE WILL DEVELOP AND TEST THREE DIFFERENT METHODS OF MEASURING ACCOMMODATION, INCLUDING DARK FOCUS, IN TERMS OF RELIABILITY, STABILITY, SENSITIVITY, AND FEASIBILITY.