[Characteristics and analysis of corneal astigmatism in age-related cataract patients over 50 years old].

ABSTRACT

Objective: To investigate the relationship between corneal astigmatism and age, axial length (AL) in age-related cataract patients over 50 years old. Methods: In this retrospective study, 1 906 eyes of 953 patients with age-related cataract were diagnosed from February 2016 to August 2016 atPeking University People's Hospital, and their demographics, preoperative AL, magnitude and meridian of the corneal astigmatism measured by IOL Master were collected. Restricted cubic splines and Spearman rank correlation coefficients were used to investigate the relationship of the magnitude of cornea astigmatism to age. Chi-square test was used to assess the relationship of the meridian of astigmatism to age, AL and the magnitude of cornea astigmatism. Results: The patients were 410 men and 543 women. The corneal astigmatism was with-the-rule (WTR) in 570 eyes (29.91%), against-the-rule (ATR) in 1 005 eyes (52.73%) and oblique in 331 eyes (17.37%). The mean age was (72±9) years old. The medians (min, max) of AL and corneal astigmatism magnitude were 23.49 mm (19.83 mm to 33.89 mm) and 0.97 D (0.06 D to 4.65 D) in right eyes and 23.41 mm (17.54 mm to 32.09 mm) and 0.92 D (0.11 D to 4.88 D) in left eyes, respectively. The corneal astigmatism was ≥0.75 D in 64.95% (619/953) of the right eyes and 61.59% (587/953) of the left eyes. Among the elderly patients over 65 years old, when the AL was between 22.00-25.99 mm (r=0.186-0.279), the value of corneal astigmatism was positively correlated with age (all P<0.01) in both eyes. The value of ATR corneal astigmatism was positively correlated with age (right eyes, r=0.278, P<0.01; left eyes, r=0.225, P<0.01), while the value of WTR corneal astigmatism had no statistically significant correlation with age (right eyes, P=0.335; left eyes, P=0.633). The prevalence of WTR astigmatism decreased with age from 43.81% (46/105) to 20.73% (51/246) in right eyes and from 40.00% (42/105) to 24.80% (61/246) in left eyes, while the prevalence of ATR astigmatism increased with age from 38.10% (40/105) to 61.38% (151/246) in right eyes and from 33.33% (35/105) to 58.94% (145/246) in left eyes. The prevalence of oblique astigmatism was not significantly changed with age (right eyes, χ(2)=31.986, P<0.01; left eyes, χ(2)=27.686, P<0.01). There was no statistically significant difference in the distribution of corneal astigmatism meridians between different AL groups (right eyes, P=0.497; left eyes, P=0.897). With the increase of the magnitude of corneal astigmatism, the prevalence of oblique astigmatism significantly decreased from 25.45% (85/334) to 0 in right eyes and from 29.78% (109/366) to 1.35% (1/74) in left eyes, while the prevalence of ATR astigmatism significantly increased from 39.82% (133/334) to 79.27% (65/82) in right eyes and from 41.80% (153/366) to 59.46% (44/74) in left eyes (right eyes, χ(2)=72.229, P<0.01; left eyes, χ(2)=72.166, P<0.01). Conclusions: A majority of age-related cataract patients over 50 years old have astigmatism ≥0.75 D before cataract surgery. When the AL is between 22.00 mm and 25.99 mm, the magnitude of corneal astigmatism increases with age among people over 65 years old, especially the magnitude of ATR corneal astigmatism, while the magnitude of WTR corneal astigmatism has no obvious increase with age. The percentage of ATR astigmatism increases while the percentage of WTR astigmatism decreases with age. (Chin J Ophthalmol, 2020, 56 349-355).