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AIM: To compare the accuracy of different intraocular lens(IOL)calculation formulas in cataract patients with axial length longer than 28mm and a history of radial keratotomy(RK).METHODS: Retrospective study. The medical records of 19 cataract patients(29 eyes)after RK and with axial length longer than 28mm who underwent cataract surgery from January 2011 to July 2020 in Beijing Tongren Hospital were analyzed. The absolute error(AE)of the difference among three different formulas was calculated. AE refers to the absolute value between the actual spherical equivalent after cataract surgery and the spherical equivalent predicted by the IOL formula. The AE values of the three formulas and the percentages of eyes with AE≤0.5, 0.75, 1.0, and 2.0D were calculated and compared.RESULTS: The AE values of the three formulas were significantly different(χ2=8.759, P=0.013). The Barrett True-K formula had the smallest median AE, which was only 0.62(0.20, 1.15)D, followed by the Haigis formula 0.76(0.34, 1.26)D, and the Holladay 1(D-K)formula had the largest 1.01(0.49, 1.62)D. The percentages of affected eyes with AE ≤0.5, 0.75, 1.0, and 2.0D for the Barrett True-K formula were 48%, 59%, 69%, and 93%, which were equal to or higher than the other two formulas.CONCLUSION: The Barrett True-K formula is more recommended among the three formulas for cataract patients after RK and with axial length longer than 28 mm.
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Objective To assess the outcomes of OASIS iris expander in phacoemulsification surgery of cataract with small pupil.Methods A prospective case-control study was conducted in 22 microcoria cataract patients (22 eyes).And they were randomly divided into group A and B,in which the pupils of group A were dilated by tearing instruments in 13 eyes,and the pupils of group B were dilated using OASIS iris expander in 9 eyes.All patient underwent phacoemulsification with 3.2 mm clear corneal incision and were followed up at postoperative 1 week,1 month,3 months and 6 months.Finally,the best corrected visual acuity (BCVA),intraocular pressure (IOP),corneal endothelial cell counts,pupil size before and after surgery were recorded and analyzed by an independent sample t test.Results All procedures were completed successfully by the same skilled doctor.Intraocular lenses were implanted in capsule completely,and no complications occurred.At 6 months after operation,patients'BCVA in group A (0.41 ± 0.30) and group B (0.77 ± 0.23) was significantly higher than that in group A (0.17 ±0.14) and group B (0.16 ±0.14) before operation,but there was no statistical difference between the two groups (all P ＞0.05);whereas there was no significant change in the IOP of group A and B at 6 months after operation (1 kPa =7.5 mmHg) and before operation [(14.22 ±6.00) mmHg vs.(15.70 ± 5.70) mmHg)] (all P ＞ 0.05).Moreover,corneal endothelial cell counts in group A [(1486 ±718) cells · mm-2] and B [(1246 ±516)cells · mm-2] were significantly smaller than those before operation [(2498 ±564)cells · mm-2 vs.[(2424 ± 640) cells · mm-2],with no significant difference (P=0.091).The postoperative diameter of the pupil in group A [(4.00 ±0.88) mm] and group B [(4.70 ± 1.57) mm] after operation was larger than that in group A [(2.30 ±0.35)mm] and group B [(1.94 ±0.50)mm] before operation,and there was no statistical difference between the two groups (all P ＞0.05).Conclusions OASIS iris expander can help to dilate and hold pupils and does not affect the postoperative visual acuity and intraocular pressure in mlcrocoria cataract phacoemulsification.The postoperative pupils become larger,and it is necessary to pay attention to protect corneal endothelial cell during usage of OASIS iris expander.
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Objective To investigate the correlation of wavefront aberration and myopic development in school-age children.Methods Together 150 school-age children (300 eyes) in Beijing city were collected and underwent cycloplegic refractometry for detect the refraction status and Allegretto wavefront aberrometry for the measurement of wavefront aberration for 1-year follow up.Results Totally 132 children were successfully followed up and only 120 children were included in this study.The average increased diopter was (0.74 ± 0.55) D.It was found that the development of myopia was correlated with age,myopic duration and the baseline diopter (all P ＜ 0.01),and the wavefront aberration was correlated with age (P ＜ 0.05).There were significant difference in the third order RMS value and C7 (coma) between the myopic children with rapid progress and slow progress.C12 (spherical aberration) was significantly correlated with the change of diopter (P ＜ 0.05).Conclusion Both third order RMS and C7 (coma) may be the major contributors for myopia progress in school-age children,and the increased diopter may polarize the spherical aberration toward minus values.
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<p><b>BACKGROUND</b>Optical Quality Analysis System II (OQAS, Visiometrics, Terrassa, Spain) that uses double-pass (DP) technique is the only commercially available device that allows objective measurement of ocular retinal image quality. This study aimed to evaluate the impact of spectacle lenses on the ocular optical quality parameters and the validity of the optometer within OQAS.</p><p><b>METHODS</b>Seventy eyes of healthy volunteers were enrolled. Optical quality measurements were performed using OQAS with an artificial pupil diameter of 4.0 mm. Three consecutive measurements were obtained from spectacle correction corresponding to subjective refraction and from the OQAS built-in optometer separately. The modulation transfer function cutoff frequency, the Strehl ratio, the width of the point spread function (PSF) at 10% of its maximal height (PSF10), and the width of the PSF at 50% of its maximal height (PSF50) were analyzed.</p><p><b>RESULTS</b>There was no significant difference in any of the parameters between the spectacle correction and the optometer correction (all P > 0.05, paired t-test). A good agreement was found between both the methods and a good intraobserver repeatability in both the correction methods. Difference in best focus between two methods was the only parameter associated significantly with optical quality parameter differences. Best focus difference, built-in optometer correction with or without external cylindrical lens, and age were associated significantly with PSF10 difference. No linear correlation between refractive status and optical quality measurement difference was observed. A hyperopic bias (best focus difference of (0.50 ± 0.44) D) and a relatively better optical quality using spectacle correction in high myopia group were found.</p><p><b>CONCLUSIONS</b>OQAS based on DP system is a clinically reliable instrument. In patients with high myopia, measurements using built-in optometer correction should be considered and interpreted with caution.</p>
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Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Refração Ocular , Acuidade Visual , FisiologiaRESUMO
<p><b>OBJECTIVE</b>To observe the therapeutic efficacy and the mechanism of Chinese medicine eye-patch with invigorating blood circulation and detoxification on asthenopia.</p><p><b>METHODS</b>A total of 180 rabbits were subjected to three tests, namely the skin microcirculation, the microvascular regeneration in the skin and the skin temperature change, with 60 rabbits for each test. The rabbits in each test were randomly and equally divided into three groups: the normal control group was treated with physiological saline on naked back once per day, the low dose group was treated with the eye-patch on naked back for 15 min once per day, while the high dose group was treated for three times per day. Forty Hartley guinea pigs were randomly and equally divided into four groups for the muscle tone test: the normal control group was treated with physiological saline on naked back, the model group was treated without any medication, the low dose group was treated with the eye-patch on naked back for 10 min once per day, while the high dose group was treated for three times per day. All treatments were continued for 14 days until the termination of the test. The microcirculatory blood flow was observed by using a video-microscopy system. The histological sections were used to detect the microvascular regeneration by observing the expression of factor VIII. The temperature changes on the skin surface were measured by using infrared thermometer, and the muscle tone was tested by the electromyography.</p><p><b>RESULTS</b>In compare with the normal or the model group, the improvement in the skin microcirculation and the blood vascular regeneration, and the decreasing in the muscle tone in low dose and high dose groups were statistically significant with confident level at P<0.05.</p><p><b>CONCLUSIONS</b>The eye-patch with invigorating blood circulation and detoxification has great enhancement in blood vascular regeneration and skin microcirculation, and great improvement in the indexes for muscle tone. The study explains certain therapeutic efficacy and mechanism of the eye-patch and shows that it could reduce the symptoms for patients with asthenopia.</p>