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Darren,
The high-power eyieces (basically anything under 9mm) are mainly used for observing planets, double stars and occasionally the moon. In these cases A wide field isn't important - what matters more is sharpness, extremely good contrast free of scattered light and internal reflections, and these are achieved by having as few air-glass surfaces as possible. This is why older designs like plossl or orthos (and modern variants such as the TMB planetaries) and even the humble Edmund RKE are still popular in short focal lengths.
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