PURPOSE: To determine why the reading addition increases after the age of 55 to 60 years when accommodation is zero. METHODS: Distance and near visual acuities, arm length, habitual near working distance, reading addition, and pupil diameter were measured in 44 subjects aged >60 years (mean, 72.9 +/- 5.7). Reading addition values were attained using three techniques: least-plus addition using both N-notation text and MN-READ text and the cross-cylinder technique. RESULTS: The mean dioptric working distance was 2.75 +/- 0.40 D. The reading addition found using N-notation text (+2.21 +/- 0.38 D) was significantly lower than that measured using MN-READ text (+2.48 +/- 0.49 D) or the cross-cylinder method (+2.53 +/- 0.44 D). The reading addition was positively correlated with the dioptric working distance (r = 0.47, p < 0.01), and decreasing habitual working distance was associated with poorer visual acuity (r = -0.42, p < 0.01). CONCLUSIONS: Our results suggest that decreases in near visual acuity after 60 years of age lead to a reduction in habitual working distance, which increases text angular subtense. In turn, the reduced working distance requires a greater reading addition. Increases in depth of field associated with both suprathreshold text (N-notation) and lower visual acuity lead to reading additions being less than the dioptric working distance.
PURPOSE: To determine why the reading addition increases after the age of 55 to 60 years when accommodation is zero. METHODS: Distance and near visual acuities, arm length, habitual near working distance, reading addition, and pupil diameter were measured in 44 subjects aged >60 years (mean, 72.9 +/- 5.7). Reading addition values were attained using three techniques: least-plus addition using both N-notation text and MN-READ text and the cross-cylinder technique. RESULTS: The mean dioptric working distance was 2.75 +/- 0.40 D. The reading addition found using N-notation text (+2.21 +/- 0.38 D) was significantly lower than that measured using MN-READ text (+2.48 +/- 0.49 D) or the cross-cylinder method (+2.53 +/- 0.44 D). The reading addition was positively correlated with the dioptric working distance (r = 0.47, p < 0.01), and decreasing habitual working distance was associated with poorer visual acuity (r = -0.42, p < 0.01). CONCLUSIONS: Our results suggest that decreases in near visual acuity after 60 years of age lead to a reduction in habitual working distance, which increases text angular subtense. In turn, the reduced working distance requires a greater reading addition. Increases in depth of field associated with both suprathreshold text (N-notation) and lower visual acuity lead to reading additions being less than the dioptric working distance.
Authors: Aurélie Calabrèse; Allen M Y Cheong; Sing-Hang Cheung; Yingchen He; MiYoung Kwon; J Stephen Mansfield; Ahalya Subramanian; Deyue Yu; Gordon E Legge Journal: Invest Ophthalmol Vis Sci Date: 2016-07-01 Impact factor: 4.799
Authors: Negareh Yazdani; Abbas Azimi Khorasani; Hanieh Mirhajian Moghadam; Abbas Ali Yekta; Hadi Ostadimoghaddam; Javad Heravian Shandiz Journal: J Ophthalmic Vis Res Date: 2016 Jul-Sep