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Absolute value of dioptric changes in cylinder refraction changes in the non-CSA and CSA groups. No-change subgroup, no change in diopters; increase subgroup, increases in diopters; decrease subgroup, decreases in diopters. Change 1: dioptric change = 0 D; Change 2: dioptric change >0 to <0.5 D; Change 3: dioptric change ≥0.5 D to <1.0 D; Change 4: dioptric change ≥1.0 D.
