Overnight Orthokeratology Compared With Atropine in Myopia
Overnight Orthokeratology Compared With Atropine in Myopia
In the OK lens group, 105 patients (53 males and 52 females) who successfully completed the 3-year follow-up examinations were enrolled. Their ages ranged from 7 to 17 years (average, 11.82 ± 1.25 years). Sixteen (15.24%) patients were aged 7–9 years, 70 (66.67%) were aged 10–13 years, and 19 (18.83%) were aged 14–17 years (Table 2). At baseline, their myopia ranged from 1.5 to 7.5 D (average, 4.25 ± 1.5 D), and astigmatism ranged from 0 to 2.75 D (average, 0.75 ± 0.75 D); logMAR uncorrected visual acuity (UCVA) was between 0.20 and 1.40 logMAR (mean, 0.80 ± 0.45), and axial length ranged from 22.05 to 27.05 mm (mean, 24.12 ± 1.25 mm; Table 2). In the atropine group, 105 patients (53 males and 52 females) used 0.125% atropine every night throughout the 3-year follow-up (Table 2). Their ages ranged from 7 to 17 years (average, 11.12 ± 1.68 years). Twenty-three (21.91%) patients were aged 7–9 years, 70 (66.67%) were aged 10–13 years, and 12 (11.41%) were aged 14–17 years. Among the 105 subjects, 90 (90.5%) patients required spectacles to perform daily activities. At baseline, their myopia ranged from 1.5 to 7.5 D (average, 4.0 ± 1.75 D; Table 2) and astigmatism was between 0 and 2.75 D (average, 0.5 ± 0.75 D; Table 2); UCVA ranged from 0.10 to 1.40 logMAR (mean, 0.81 ± 0.28; Table 2), and axial length ranged from 21.12 to 27.23 mm (mean, 24.23 ± 1.35 mm; Table 2). At baseline, the 2 groups were comparable in terms of myopia (p = 0.975), astigmatism (p = 0.897), and axial length (p = 0.985) (Table 2). All demographic data on UCVA, axial length, age, and gender are listed in Table 2; there were no significant differences in all the baseline conditions between the groups.
Using linear regression analysis, we found that myopia increased by 0.28 D ± 0.18 D and 0.34 D ± 0.21 D per year in the OK lens group and the atropine group, respectively (Table 3). The change in myopia diopters per year was 0.29 ± 0.31 D, 0.27 ± 0.24 D, and 0.28 ± 0.31 D in the OK lenses group, and 0.31 ± 0.19 D, 0.35 ± 0.85 D, and 0.32 ± 0.53 D in the atropine group for years 1, 2, and 3, respectively (Table 4). The change in axial length per year was 0.28 ± 0.08 mm and 0.37 ± 0.09 mm in the OK lens group and the atropine group, respectively (Table 3). The change in axial length per year was 0.28 ± 0.08 mm, 0.30 ± 0.09 mm, and 0.27 ± 0.10 mm in the OK lens group, and 0.38 ± 0.09 mm, 0.37 ± 0.12 mm, and 0.36 ± 0.08 mm in the atropine group for years 1, 2, and 3, respectively (Table 4). There are also significant but weak differences comparing axial length and myopic degree each year and data are not showed. We also compared the changes in the group aged 10–13 years; the averaged changes of myopia were 0.29 ± 0.21 D and 0.34 ± 0.31 D in OK lens and atropine groups per years (p = 0.003). The averaged changes of axial length per years: OK lens and atropine groups were 0.29 ± 0.11 mm and 0.37 ± 0.12 mm, respectively (p = 0.0035). Astigmatism (analyzed using a negative cylinder) changed by ±0.02 D and ±0.01 D per year in the OK lens group and the atropine group, respectively (Table 3); the axis of astigmatism did not show significant changes during the study period in the 2 groups.
The change in mean cornea endothelium cell count was not significantly different between the OK lens and atropine group (change per year, ±38 cell/mm and ±30 cell/mm; p = 0.785). The UCVA of the OK lens group was 0.2 logMAR (20/30) to -0.1 logMAR (20/16), and BCVA of the atropine group was 0.1 logMAR (20/25) to -0.1 logMAR (20/16) at 2 and 4 pm, respectively.
To understand the relationship between the refractive error at baseline and increased axial length, Pearson's correlation coefficient was employed. Significant correlation was found between these parameters in the OK lens group (Pearson's correlation coefficient; r = 0.259, p < 0.001) as well as in the atropine group (r = 0.169, p = 0.014; Figures 1 and 2). The effect of decreasing the progression of axial length was more pronounced in high myopia patients than in low myopia patients for both groups. The regression coefficient (β) was higher in the OK lens group than in the atropine group (β = 0.060 [OK lens group] and 0.029 [atropine group], respectively).
(Enlarge Image)
Figure 1.
Increases in axial length (mm) and refractive errors (myopia [D]) at baseline in the OK group. A significant correlation was found between the increases in axial length and spherical equivalent refractive errors (myopia [D]) at the baseline. Pearson's correlation coefficient: r = 0.259, p < 0.001.
(Enlarge Image)
Figure 2.
Increases in axial length (mm) and refractive errors (myopia [D]) at baseline in the atropine used group. A significant correlation was found between the increases in axial length and spherical equivalent refractive errors (myopia [D]) at the baseline. Pearson's correlation coefficient: r = 0.169, p = 0.014.
In the OK lens group, the most common complication was allergic conjunctivitis; in 37 eyes (17.6%), there was an uncomfortable feeling such as itching during daytime, watery discharge on awaking, and requirement of drugs for relieving the symptoms. The care solution of OK lens used were "Boston Conditioning Solution and Boston Cleaner" (Bausch & Lomb Taiwan Ltd, Taiwan) or BIOCLEN Contact Lens Solution (BIOCLEN OPHTECS, Japan). Fifteen eyes (7.14%) showed superficial keratitis, which improved 3–7 days after terminating the use of OK lenses, without the need for drug administration and the OK lens were used continuously after re-education the taking care methods of the lens. No other complications, including corneal ulcers, were noted. In the atropine group, 2 eyes (1 patient [0.095%]) showed mild allergic blepharitis, which improved after topical application of anti-allergy medication. In OK lens group, the patients with myopia over then 5.75 D would use double reverse curves and dual geometric (DG) designs OK lens from Euclid Systems Corp. Their UCVA were better then 0.2 logMAR at 2–4 pm and just 2 patients needed spectacles at evening for taking lessons after school, none of the other needed spectacles in daily life. The major complaints of atropine application were photophobia during the day (35%), which could be resolved by photochromic lenses or sunglasses (72%), and poor near visual acuity (12%), which could be improved by multifocal lenses in most patients (96%). As for the effects of multifocal lenses and photochromic lenses for delaying myopia progression are also important subjects but are not the main themes in this study and need another investigation. No other evident abnormality was noted during the treatment period.
Results
In the OK lens group, 105 patients (53 males and 52 females) who successfully completed the 3-year follow-up examinations were enrolled. Their ages ranged from 7 to 17 years (average, 11.82 ± 1.25 years). Sixteen (15.24%) patients were aged 7–9 years, 70 (66.67%) were aged 10–13 years, and 19 (18.83%) were aged 14–17 years (Table 2). At baseline, their myopia ranged from 1.5 to 7.5 D (average, 4.25 ± 1.5 D), and astigmatism ranged from 0 to 2.75 D (average, 0.75 ± 0.75 D); logMAR uncorrected visual acuity (UCVA) was between 0.20 and 1.40 logMAR (mean, 0.80 ± 0.45), and axial length ranged from 22.05 to 27.05 mm (mean, 24.12 ± 1.25 mm; Table 2). In the atropine group, 105 patients (53 males and 52 females) used 0.125% atropine every night throughout the 3-year follow-up (Table 2). Their ages ranged from 7 to 17 years (average, 11.12 ± 1.68 years). Twenty-three (21.91%) patients were aged 7–9 years, 70 (66.67%) were aged 10–13 years, and 12 (11.41%) were aged 14–17 years. Among the 105 subjects, 90 (90.5%) patients required spectacles to perform daily activities. At baseline, their myopia ranged from 1.5 to 7.5 D (average, 4.0 ± 1.75 D; Table 2) and astigmatism was between 0 and 2.75 D (average, 0.5 ± 0.75 D; Table 2); UCVA ranged from 0.10 to 1.40 logMAR (mean, 0.81 ± 0.28; Table 2), and axial length ranged from 21.12 to 27.23 mm (mean, 24.23 ± 1.35 mm; Table 2). At baseline, the 2 groups were comparable in terms of myopia (p = 0.975), astigmatism (p = 0.897), and axial length (p = 0.985) (Table 2). All demographic data on UCVA, axial length, age, and gender are listed in Table 2; there were no significant differences in all the baseline conditions between the groups.
Using linear regression analysis, we found that myopia increased by 0.28 D ± 0.18 D and 0.34 D ± 0.21 D per year in the OK lens group and the atropine group, respectively (Table 3). The change in myopia diopters per year was 0.29 ± 0.31 D, 0.27 ± 0.24 D, and 0.28 ± 0.31 D in the OK lenses group, and 0.31 ± 0.19 D, 0.35 ± 0.85 D, and 0.32 ± 0.53 D in the atropine group for years 1, 2, and 3, respectively (Table 4). The change in axial length per year was 0.28 ± 0.08 mm and 0.37 ± 0.09 mm in the OK lens group and the atropine group, respectively (Table 3). The change in axial length per year was 0.28 ± 0.08 mm, 0.30 ± 0.09 mm, and 0.27 ± 0.10 mm in the OK lens group, and 0.38 ± 0.09 mm, 0.37 ± 0.12 mm, and 0.36 ± 0.08 mm in the atropine group for years 1, 2, and 3, respectively (Table 4). There are also significant but weak differences comparing axial length and myopic degree each year and data are not showed. We also compared the changes in the group aged 10–13 years; the averaged changes of myopia were 0.29 ± 0.21 D and 0.34 ± 0.31 D in OK lens and atropine groups per years (p = 0.003). The averaged changes of axial length per years: OK lens and atropine groups were 0.29 ± 0.11 mm and 0.37 ± 0.12 mm, respectively (p = 0.0035). Astigmatism (analyzed using a negative cylinder) changed by ±0.02 D and ±0.01 D per year in the OK lens group and the atropine group, respectively (Table 3); the axis of astigmatism did not show significant changes during the study period in the 2 groups.
The change in mean cornea endothelium cell count was not significantly different between the OK lens and atropine group (change per year, ±38 cell/mm and ±30 cell/mm; p = 0.785). The UCVA of the OK lens group was 0.2 logMAR (20/30) to -0.1 logMAR (20/16), and BCVA of the atropine group was 0.1 logMAR (20/25) to -0.1 logMAR (20/16) at 2 and 4 pm, respectively.
To understand the relationship between the refractive error at baseline and increased axial length, Pearson's correlation coefficient was employed. Significant correlation was found between these parameters in the OK lens group (Pearson's correlation coefficient; r = 0.259, p < 0.001) as well as in the atropine group (r = 0.169, p = 0.014; Figures 1 and 2). The effect of decreasing the progression of axial length was more pronounced in high myopia patients than in low myopia patients for both groups. The regression coefficient (β) was higher in the OK lens group than in the atropine group (β = 0.060 [OK lens group] and 0.029 [atropine group], respectively).
(Enlarge Image)
Figure 1.
Increases in axial length (mm) and refractive errors (myopia [D]) at baseline in the OK group. A significant correlation was found between the increases in axial length and spherical equivalent refractive errors (myopia [D]) at the baseline. Pearson's correlation coefficient: r = 0.259, p < 0.001.
(Enlarge Image)
Figure 2.
Increases in axial length (mm) and refractive errors (myopia [D]) at baseline in the atropine used group. A significant correlation was found between the increases in axial length and spherical equivalent refractive errors (myopia [D]) at the baseline. Pearson's correlation coefficient: r = 0.169, p = 0.014.
In the OK lens group, the most common complication was allergic conjunctivitis; in 37 eyes (17.6%), there was an uncomfortable feeling such as itching during daytime, watery discharge on awaking, and requirement of drugs for relieving the symptoms. The care solution of OK lens used were "Boston Conditioning Solution and Boston Cleaner" (Bausch & Lomb Taiwan Ltd, Taiwan) or BIOCLEN Contact Lens Solution (BIOCLEN OPHTECS, Japan). Fifteen eyes (7.14%) showed superficial keratitis, which improved 3–7 days after terminating the use of OK lenses, without the need for drug administration and the OK lens were used continuously after re-education the taking care methods of the lens. No other complications, including corneal ulcers, were noted. In the atropine group, 2 eyes (1 patient [0.095%]) showed mild allergic blepharitis, which improved after topical application of anti-allergy medication. In OK lens group, the patients with myopia over then 5.75 D would use double reverse curves and dual geometric (DG) designs OK lens from Euclid Systems Corp. Their UCVA were better then 0.2 logMAR at 2–4 pm and just 2 patients needed spectacles at evening for taking lessons after school, none of the other needed spectacles in daily life. The major complaints of atropine application were photophobia during the day (35%), which could be resolved by photochromic lenses or sunglasses (72%), and poor near visual acuity (12%), which could be improved by multifocal lenses in most patients (96%). As for the effects of multifocal lenses and photochromic lenses for delaying myopia progression are also important subjects but are not the main themes in this study and need another investigation. No other evident abnormality was noted during the treatment period.