Archaeological Vision at Çatalhöyük: Shelters, Sun and Funny Looking Glasses Testing Procedures

The test employed for this study is the Pelli-Robson contrast sensitivity test. This test is a poster made up of triplets of letters that gradually change from black letters on white (high contrast) to very light gray letters on white (low contrast). Under controlled, clinical viewing conditions, this test is used to diagnose certain eye diseases and degrading contrast sensitivity in individuals.

I chose this test for several reasons:

a) Contrast sensitivity is a good marker for assessing vision in archaeology due to the repetitive nature of the work. Prolonged periods of working under the same lighting conditions while looking at a similar color matrix leads to a desensitization to the stimulus through adaptation. In other words, you become less sensitive to subtle differences in the viewed material, be it under bright sunlight or shelter.

b) Due to time constraints in the field and the desire to test as many people as possible under different viewing conditions, I needed to limit the testing 'battery' to one easy-to-perform test. The PRCS test takes less than five minutes to administer on both eyes.

c) This test of letters is recognizable by all members in the testing group. Contrast sensitivity tests can also take the form of gradients (insert figure here) that would be more difficult to explain to non-English speakers, although they have many benefits over letter tests (see Future Plans below).

Under exposed conditions, members were tested with their naked eyes several times per day. Members were also tested wearing one of two pairs of glasses. These glasses block 100% ultraviolet (UV), dramatically reduce glare and a large amount of ambient light. One pair was tinted amber (warm) and the other was gray (cool). Members would wear the glasses for a minimum of ten minutes to allow their eyes to accommodate and then the test was re-administered.

Serdar tries out the gray 'specs'

Katy in the flotation area

Members who worked under shelters, be it the BACH shelter, flotation or the sorting area, were tested under normal working conditions, again at several times per day. Members who worked in exposed sun conditions (TP and South) were tested under full sun, cloudy conditions and also at several times during the work day. Most members were also tested in the North shelter at the same time of day (around 2pm) to provide a 'normal' condition. continued