Cycloplegic refraction by 1% cyclopentolate in young adults: is it the gold standard? The Anyang University Students Eye Study (AUSES) 

Abstract

A school-based study including 7971 undergraduates was conducted in Anyang, Henan Province, China. Cycloplegia was achieved with two drops of 1% cyclopentolate and 1 drop of Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) with a 5 min interval. Non-cycloplegic and cycloplegic refractions were measured by an autorefractor. A paired-sample t-test and Spearman correlation analysis were used for analysis with data from only the right eyes included. RESULTS: Of the 7971 students examined, 7793 (97.8%) with complete data were included, aging 20.2±1.5 years. Male students accounted for 36.8%. Overall, there was a significant difference between non-cycloplegic and cycloplegic SE (spherical equivalent) of 0.83±0.81D (p<0.01). The difference was 1.80±1.11D, 1.26±0.93D and 0.69±0.69D for those with cycloplegic hyperopia, emmetropia and myopia, respectively (p<0.01 for all). Those with a hyperopic shift less than 0.25D and 0.5D accounted for 11.1% and 34.1%, respectively. A significant relationship was found between difference in SE and cycloplegic refraction (r=0.33, b=0.11, p<0.01). Without cycloplegia, prevalence of hyperopia and emmetropia would be underestimated by 6.2% (1.0% vs 7.2%) and 5.7% (3.8% vs 9.5%), respectively, with prevalence of myopia and high myopia overestimated by 12.1% (95.3% vs 83.2%) and 6.1% (17.2% vs 11.1%). CONCLUSION: Lack of cycloplegia will lead to significant misclassification of myopia, emmetropia and hyperopia in Chinese young adults. Cycloplegia is therefore essential for this age-group in epidemiological studies.

Refractive Errors in University Students in Central China: The Anyang University Students Eye Study

“…32,35,40,41 Furthermore, in our previous study comparing the differences between cycloplegic and noncycloplegic refraction among these university students, a similar prevalence of 95.3% was found if myopia was defined by noncycloplegic refraction, while it decreased to 83.2% with myopia defined by cycloplegic refraction. 39 Thus, the prevalence of myopia and high myopia seems to be overestimated in their study. The prevalence of myopia in our study was higher than that reported in university students from Europe and the United States, [16][17][18][19][20][21][22] while consistent with prevalence reported in other studies in Asia, such as those in Taiwan, 23 and Singapore (Table 4).…”

“…32 Besides, cycloplegia by 1% cyclopentolate for those university students was also proved to be necessary in our previous paper, which reported a similar prevalence of myopia based on noncycloplegic refraction with theirs (95.3% vs. 95.5%). 39 Therefore, this is the first well-designed and large-scale study with comprehensive ophthalmologic examinations and cycloplegic data among university students in mainland China. In this paper, we report the prevalence of refractive errors, as well as the potential impact of demographic factors, with data on other ophthalmic diseases to be presented elsewhere.…”

School-based epidemiology study of myopia in Tianjin, China

“…This evidence proved it a reliable screener for myopia. However, given the fact that the data from non-cycloplegic photoscreeners tend to over-estimate the prevalence of myopia [ 18 , 33 , 34 ], the actual prevalence may be lower than reported. This has been elaborated in our previous study that the SER results from Spot photoscreener overall represent a myopic shift, with an average of − 0.17D ~ − 0.49D [ 9 ].…”

<p>Refractive errors among Saudi college students and associated risk factors</p>

“…It is important to note that refractive errors were measured without cycloplegia, which could overestimate the percentage of myopia 33. Myopia overestimation and hyperopia/emmetropia underestimation were observed previously when a cutoff of −0.5 D was used 33,34. However, the magnitude of overestimation is unknown when a cutoff of −0.75 D is used.…”

“…The high reported prevalence has been widely observed in East Asians, which could possibly be explained by the differences in environmental factors among East Asian children compared to Western children, in terms of less time spent outdoors as they are subjected to a more rigorous educational system 25–32. It is important to note that refractive errors were measured without cycloplegia, which could overestimate the percentage of myopia 33. Myopia overestimation and hyperopia/emmetropia underestimation were observed previously when a cutoff of −0.5 D was used 33,34.…”