The most common and most likely answer to this crossword clue is the 8 letter word GLAUCOMA
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More clues leading to the result GLAUCOMA
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The cryptic/wordplay part
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What does GLAUCOMA mean?
GLAUCOMA noun- An eye disease or disorder that is defined as a characteristic optic neuropathy, or disease of the optic nerve, possibly, if untreated, leading to damage of the optic disc of the eye and resultant visual field loss due to lack of communication between the retina and the brain, which can lead to blindness.