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Takako Tachikawa, Ritsuko Ueno, Daisuke Yuzurihara, Tetsuko Mita, Osamu Katsumi, Toru Noda, Kazuhiko Ohnuma; Cornea, crystalline lens and whole ocular refractive power in premature infants with retinopathy of prematurity at one year of age. Invest. Ophthalmol. Vis. Sci. 2013;54(15):590.
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To investigate the corneal, crystalline lens, and whole ocular refractive powers in premature 1-year-old infants with retinopathy of prematurity (ROP) using a method we devised to determine the refractive power in infants.
We studied 50 eyes (50 infants with ROP; overall mean gestational age, 25.3±1.9 weeks; range, 22-29; mean birth weight, 763.3±195.5 g; range, 438-1,230) at 1 year corrected age. The patients were divided into 3 primary groups: group 1, 29 untreated eyes; group 2, 9 treated eyes (zone I and aggressive posterior ROP (APROP)); and group 3, 12 treated eyes (zone II). The spherical equivalent (SE), anterior chamber depth (ACD), axial length (AL), corneal radius (CR), and lens thickness (LT) were measured by ultrasound A-scan biometry, autorefractometry, and keratometry under cycloplegia. The individual refractive index using the Gullstrand-Emsley model (except that of the lens, which was modified to 1.43) and anterior and posterior lens curvature ratio (1.29) were used to calculate the corneal power (CP), crystalline lens power (LP) and whole ocular refractive power (WP). The parameters were compared among groups by the Student’s t-test and Tukey HSD test.
The average group 1 values were AL, 19.81±0.74 mm; CR, 7.44±0.32 mm; LT, 3.85±0.14 mm; ACD, 3.05±0.38 mm; SE, +0.56±1.10 diopters (D); CP, 45.20 D; LP, 39.01 D; and WP, 76.66 D. Group 2: AL, 18.79±0.57 mm; CR, 7.22±0.33 mm; LT, 4.32±0.22 mm; ACD, 2.23±0.35 mm; SE, -2.49±1.56 D; CP, 46.45 D; LP, 45.88 D; and WP, 84.06 D. Group 3: AL, 19.65±0.86 mm; CR, 6.88±0.24 mm; LT, 4.11±0.16 mm; ACD, 2.77±0.34 mm; SE, -0.75±2.32 D; CP, 45.12 D; LP, 41.52 D; and WP, 78.79 D. The SE differences between groups 1 and 2 were significant (p=0.041) but not between groups 1 and 3 (p=0.19). The CP differences among the 3 groups were not significant (p>0.2). The LPs differed significantly (p<0.05) among groups. The WPs differed significantly (p<0.0001) between groups 1 and 2 but not between groups 1 and 3 (p=0.11).
In premature 1-year-old infants with ROP, there was no significant difference between the group not treated with laser and zone II laser-treated group in SE and WP. Zone I and APROP laser-treated groups had higher myopia and greater WP than other groups.
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