Eyes are reduced in size and exhibit deep penetrating furrows in the retina that reach the basement membrane. Adjacent to the furrows the lamina has depressions. Ommatidial pattern is severely disorganised (appear as bent not straight columns and ommatidia are often missing in the retinal epithelium producing large gaps between the columns) and the ommatidia show altered morphology (lose hexagonal shape and appear flattened or rounded, number and spacing of photoreceptors is abnormal). Interommatidial bristles show altered morphology and spacing and are occasionally duplicated. Defects in the development of the mechanosensory bristles including the macrochaetae (bristles shafts shortened, gnarled or bent and have altered polarity), microchaetae and bristles surrounding the eye. Shortened head and scutellum. fw^U2/Df(1)KA10 transheterozygotes have reduced viability; only 15% female progeny eclose as adults and those that survive have wing defects.