[A study on the distribution characteristics of peripheral retinal defocus in children and adolescents]

Objective: To explore the distribution characteristics of peripheral retinal defocus in children and adolescents. Methods: This cross-sectional study included 500 individuals aged 3 to 18 years, who visited the People's Hospital of Lincang, the First Affiliated Hospital of Dali University and Dali Ophthalmology Hospital between January and December 2021. Data of the right eye of each participant was analyzed. There were 226 males (45.20%) and 274 females (54.80%), with an average age of (10.79±3.79) years. All participants underwent post-cycloplegic refraction, optical biometry, and intraocular pressure measurement to obtain spherical equivalent, average corneal curvature, axial length, and intraocular pressure. Multispectral refraction topography was performed to obtain topographic maps and values at various field angles and orientations of peripheral retinal defocus. Based on multispectral refraction topography, peripheral retinal defocus values were categorized as crater type, hemilateral upturn type, saddle type, and relatively flat type. The distribution of different refractive states was analyzed. Results: The spherical equivalent of the 500 participants was(-1.51±2.61) D, axial length was (24.10±1.28) mm, and average corneal curvature was (43.20±1.22) D. Among the 500 eyes, 382 exhibited hyperopic peripheral retinal defocus values, with 316 eyes (82.72%) being myopic. Myopic peripheral retinal defocus values were observed in 118 eyes, with 15 eyes (12.72%) being myopic. Among different types of peripheral retinal defocus values, 112 eyes (22.4%) exhibited a crater type, 153 eyes (30.6%) exhibited a hemilateral upturn type, 107 eyes (21.4%) exhibited a saddle type, and 128 eyes (25.6%) exhibited a flat type. The proportion of myopia was 82.14% (92 eyes), 69.28% (106 eyes), 60.75% (65 eyes), and 3.90% (5 eyes), respectively. The peripheral retinal defocus values at 15°, 30°, and 45° were (0.01±0.08) D, (0.06±0.21) D, and (0.20±0.37) D, respectively. The peripheral retinal defocus values at temporal, inferior, nasal, and superior locations were (0.58±0.69) D, (0.52±0.63) D, (0.21±0.64) D, and (-0.26±0.67) D, respectively. Notably, the superior primarily manifested as myopic, while the others were predominantly hyperopic. Conclusions: Approximately three-fourths of children and adolescents exhibit hyperopic peripheral retinal defocus values, with a higher prevalence of myopia in this subgroup. The hyperopia peripheral retinal defocus value increases with the distance from the retina to the macula. The peripheral retinal defocus values between superior and inferior, nasal and temporal locations are asymmetrical, with the temporal hyperopic peripheral retinal defocus value being most prominent and the superior myopic peripheral retinal defocus value being most evident.