Comparison of 2007-2012 Korean trends in laser peripheral iridotomy and cataract surgery rates

To investigate the association between the trends in the rates of laser peripheral iridotomy (LPI) for primary angle closure (PAC) or primary angle-closure glaucoma (PACG) and cataract surgery in Korea. Acute or subacute PAC(G) patients (251,769) along with patients who had undergone LPI (20,632) or cataract surgery (1,163,729) between 2007 and 2012 were included. The LPI rate was defined as the number of LPI cases per 100 PAC(G) patients by quarter; the cataract surgery rate was defined as the number of cataract surgeries per 100,000 population by quarter. The number of acute or subacute PAC(G) patients per 100,000 population showed a gradual increase, specifically from 45.63 in the first quarter of 2007 to 49.56 in the second quarter of 2012. The LPI rate manifested a slow decline, from 9.59 to 7.94, and the cataract surgery rate showed a sharp rise, from 260.75 to 387.53, over the same period. In other words, a negative correlation tendency between the two rate trends (r = -0.244, P = 0.273) was revealed. With respect to age, significant negative correlations were observed in the 40-49 (r = -0.488, P = 0.021) and a parts per thousand yen70 (r = -0.450, P = 0.036) groups. The respective trends in the LPI and cataract surgery rates showed a negative correlation. Although other possible explanations might exist, this result supports the hypothesis that cataract surgery contributes to a reduction in the incidence of LPI in PAC(G) patients.