After excluding the eyes with prior refractive and cataract surgery, 5474 eyes with gradable lens photographs were included in the analysis related to myopia.
Table 1 shows the associations of myopia with the cataract subtypes (nuclear, cortical, and PSC) in the GEE models. Compared with emmetropic eyes, myopic eyes were associated with an increased prevalence of nuclear (OR: 4.99, 95% confidence interval [CI]: 3.72–6.69) and PSC cataract (OR: 1.34, 95% CI: 1.30–1.39), but not with cortical cataract (OR: 0.85, 95% CI: 0.68–1.08). As SE decreased (i.e., increasing myopia), there was an increased trend of nuclear (
P < 0.001) and PSC cataract (
P < 0.001). In multivariable-adjusted analyses, a longer AL was not associated with any of the cataract subtypes, namely nuclear (OR: 1.01, 95% CI: 0.86–1.18,
P = 0.93), cortical (OR: 0.91, 95% CI: 0.81–1.01,
P = 0.08), and PSC cataract (OR: 1.09, 95% CI: 0.96–1.25,
P = 0.18).
Considering that myopic shift associated with nuclear cataract usually occurs after the age of 70 years, we performed an age-stratified analysis in those aged less and no less than 70 years, respectively.
Table 2 shows the results of an age-stratified analysis on the association of myopia with nuclear, cortical, or PSC cataract. The associations of myopia with nuclear, cortical or PSC cataract in adults older than 70 years were similar compared with their counterparts younger than 70 years. Per diopter decrease in SE was associated with an increase in nuclear cataract in adults aged both older than 70 years (OR: 1.71, 95% CI: 1.46–2.02,
P < 0.001) and younger than 70 years (OR: 1.41, 95% CI: 1.31–1.52,
P < 0.001). The mean ages of nuclear cataract cases in persons with and without myopia were 70.3 and 71.1 years, respectively (
P = 0.23).
Table 3 demonstrates the ORs of myopia for PSC and nuclear cataract using a different cutoff value for myopia. When myopia was defined as SE of less than −0.5 D to −4.5 D, the magnitude of OR did not vary significantly (lowest OR: 1.67, highest OR: 2.70). When myopia was defined as SE of less than −5.0 D to −6.0 D, the OR of myopia for PSC cataract increase dramatically (OR: 2.75 for −5.0 D; OR: 3.20 for −5.5 D; OR: 3.71 for −6.0 D). The severity of myopia was associated with an increasing trend of PSC cataract (
P for trend = 0.02). The association between nuclear cataract and myopia did not increase with increasing myopia cutoffs.