Flies expressing ParpGMR.PU have a rough eye phenotype. Ommatidia have an abnormal shape and size and ommatidial fusion is seen. The orientation of the ommatidia is disrupted; some ommatidia are rotated incorrectly and show incorrect chiral forms. A rectangular pattern of rhabdomeres is seen in some flies. The number of non-neuronal accessory cells in the eye is almost normal, although their morphology and arrangement is abnormal. The arrangement of photoreceptor clusters is slightly disordered in thid larval instar eye discs expressing ParpGMR.PU. R3/R4 cells are arranged in random orientation in each ommatidium, indicating disordered polarity. The number of apoptotic cells posterior to the morphogenetic furrow is slightly higher than normal. DNA synthesis and mitosis appear normal in these discs. The organisation of the F-actin cytoskeleton is disrupted in the eyes of 40 hour pupae expressing ParpGMR.PU; F-actin is sporadically organized at the apical surface and the spokewise pattern that is normally seen at the apical surface is almost completely absent. The normal accumulation of F-actin at the centre of the ommatidium (which is the precursor of the rhabdomere) is sometimes missing and the arrangement of the secondary and tertiary pigment cells and bristle complexes at the basal floor is also disrupted.