Analysis of Myopic Progression in Childhood Using the Korea National Health and Nutrition Examination Survey

PURPOSE: To investigate the degree, distribution, and change in refractive error in the pediatric population 5 to 20 years of age. METHODS: We collected data from 7,695 subjects aged 5 to 20 years who participated in the Korean National Health and Nutrition Examination Survey from 2008 to 2012. Non-cycloplegic refractive error was measured using an autorefractor. Mean spherical equivalent calculated from the measured refractive error data in both eyes was used. The subjects were categorized into mild, moderate, or high refractive abnormality or emmetropia according to the degree of refractive error. The degree and distribution of refractive error in all subjects and age-matched subjects were analyzed. The change in refractive error was analyzed according to age. RESULTS: Mean refractive error of the study subjects was -1.82 diopters. As subject age increased, myopia increased from +0.04 diopters at 5 years of age to -2.88 diopters at 20 years of age. Myopia was observed in 66.2% of subjects and accounted for only 18.5% of the 5-year-old subjects, but increased to 84.3% in the 20-year-old subjects. The rate among all study subjects was -0.19 diopters per year. The greatest myopic progression rate (-0.46 diopters per year) among all age groups was in subjects 7 to 9 years of age. Myopic progression continued until 16 years of age. CONCLUSIONS: The ratio of pediatric myopia subjects between 5 and 20 years of age was high in Korea. The rate of myopic progression was the fastest in subjects 7 to 9 years of age. After 16 years of age, myopic change paused.

Effect of Orthokeratologic Lenses on Myopic Progression in Childhood

PURPOSE: The present study assessed the influence of overnight orthokeratology (ortho-k) on the myopic progression in Korean children and analyzed factors affecting myopic progression. METHODS: The ortho-k group was comprised of 31 patients satisfying the inclusion criteria for ortho-k. In the ortho-k group, spherical equivalent refractive error (SER) was measured at baseline, and after 2 weeks, 6 and 12 months. The control group was comprised of 31 patients who were matched according to age, gender, and baseline SER of the ortho-k subjects. RESULTS: In the ortho-k group, the mean +/- SD changes in SER from 2 weeks to 6 months, 6 to 12 months, and 2 weeks to 12 months were -0.17 +/- 0.50 D, -0.04 +/- 0.76 D, and -0.21 +/- 0.78 D, respectively. In the control group, the changes in SER from baseline to 6 months, 6 to 12 months, and baseline to 12 months were -0.38 +/- 0.42 D, -0.44 +/- 0.38 D, and -0.82 +/- 0.68 D, respectively. Significant differences were found between changes in SER from 6 to 12 months and from baseline to 12 months (p or = -0.5 D with the group of SER change < -0.5 D, numeric values of white-to-white diameters of the 2 groups were different, and a significant correlation was found between the range of SER change and the white-to-white diameter (Pearson's r = -0.471, p = 0.008). CONCLUSIONS: Ortho-k is effective for slowing myopic progression. The smaller the white-to-white diameter, the slower the myopic progression could be.

Myopic Progression and Postoperative Exodrift in Patients with Intermittent Exotropia

PURPOSE: To investigate the relationship between myopic progression and exodrift after surgery in patients with intermittent exotropia (X[T]). METHODS: Eighty-five patients who underwent bilateral lateral rectus recession for X(T) and had a follow-up of more than 1 year were recruited for the present study. Progression of myopia was determined by measuring the difference in spherical equivalent of both eyes between the initial and final refraction divided by the total follow-up time per patient. Postoperative exodrift was calculated by subtracting the deviation at postoperative 6 weeks from the deviation at the last follow-up, and the deviation at postoperative day 1 from the deviation at postoperative 6 weeks. Linear regression was conducted to determine the relationship between postoperative exodrift and myopic progression. The risk factors for recurrence, defined as exodeviation of 10 prism diopters or more at the final examination, were also analyzed. RESULTS: Sixty-eight (80.0%) subjects showed myopic progression of -0.50 diopters or more, and 47 (55.3%) had recurrence of exotropia during the mean follow-up period of 37.9 months. Patients with myopic progression showed more exotropic drift after postoperative 6 weeks than the patients without myopic progression (p < 0.01). Immediate postoperative overcorrection, oblique dysfunction, and a short follow-up period were associated with a low recurrence, whereas preoperative angle of exodeviation, sensory status, and age at the time of surgery were not. CONCLUSIONS: In patients who underwent bilateral lateral rectus recession for X(T), a greater myopic progression was related with greater postoperative exodrift. As the development of myopia was observed to be axial in nature, the results from the present study raises the possibility that ocular elongation may reduce the effect of recession.

The Effect of Atropine on Myopic Progression in Children

PURPOSE: To examine the effects of atropine therapy on myopic progression in myopic children. METHODS: Fifty myopic patients, aged from 7 to 14 years and less than -5 diopters, visited our clinic for correction of refractive error from August 2001, and were followed up for at least 1 year. Of these 50 patients, the atropine therapy group was 23 and the control group was 27. Right eye cycloplegic refraction and axial length changes of the two groups were compared and analyzed. RESULTS: There was a mean increase of myopia of 0.25+/-0.43 D/yr in the atropine therapy group and of 0.83+/-0.37 D/yr in the control group (P=0.000). There was a mean increase of axial length of 0.12+/-0.19 mm/yr in the atropine therapy group and 0.39+/-0.21 mm/yr in the control group (P=0.000). In refraction and axial length changes according to age, there was no statistically significant difference within the group, aged from 7 to 9 years. However, there was a statistically significant difference within the group, aged from 10 to 14 years. In refraction and axial length changes according to myopic grade, there were a statistically significant differences between the groups. CONCLUSIONS: Atropine therapy is effective in slowing the myopic progression in myopic children with refractive error less than -5 diopters.

The Pro g ression of Myopia Associated with Retinopathy of Prematurity

PURPOSE: To discover the characteristics and rates of myopic progression with increasing age in children who have had history of retinopathy of prematurity (ROP). METHODS: Retrospective chart review was performed of 72 eyes in 36 children who were diagnosed with ROP. Inclusion criteria were myopia over -0.5 diopter and the children that could have been followed for at least 5 years or longer. The subjects with stage 4 or 5 ROP were excluded. Data on the retinoscopic refractions at every 6 month in each patient were recorded. We measured the annual rates of myopic progression in each subgroup which were divided according to the severity of ROP, treatment modality, and the different age intervals. RESULTS: Overall annual rates of myopic progression was -0.53 D/year. The severity of ROP was not correlated with the degree of myopia and the rates of myopic progression. In terms of the rates of myopic progression, statistical significance was found only in subgroups who were treated by cryotherapy. The myopia in age group over 5 years showed less progression than that in age group under 5 years. In the patients with anisometropia, there was a tendency that the discrepancy in the refractions of both eyes decreased gradually with increasing age although there was no statistical significance. CONCLUSIONS: The rate of myopic progression was not directly correlated with the severity of ROP. But the myopia in patients who had undergone cryotherapy showed a marked progression with significantly higher rate.

Myopic Progression According to the Age of Onset in Childhoods

It is well known that the myopic progression in myopic children is related with the age of onset, and the amounts of myopia. The authors performed cycloplegic refraction in 75 children, which were less than -1.50 diopters initially. They were divided in 4 groups according to the age of onset of myopia ; group A[less than 3 years], group B[4-6 years] , group C[7-10 years], and group D[11-15 years]. The authors investigated the myopic progression according to the age of onset at one, two, and three years. The overall annual progression was 0.67+/-0.37D per a year. The most rapid progression was noted in group B, 0.92+/-0.33D per a year, and lowest rate in group D, 0.35+/-0.26D per a year. There was most rapid progression with 0.73+/-0.35D per a year during the one year after the onset of myopia. But there was no difference with respect to sex. Therefore, children with age of the onset of myopia in 4-6, and 7-10 years before puberty appeared to show more rapid progression than other groups. And one year after onset of myopia showed the most rapid myopic progression.