Objective To observe the distribution of macular thickness and its relationship with axial length, gender, refraction status and race in six-year-old children. Methods 1543 six-year-old children from 34 schools in Sydney were randomly selected. The thickness of center macula（CM）, inner macula（IM）and outer macula（OM）were measured by optical coherence tomography（OCT）, the differences of macular thickness between different genders and races were comparatively analyzed. The axial length and refraction status of all children were measured by IOL Master and autorefractor RK-F1 respectively. Results The CM, IM and OM thickness of all those six-year-old children were normally distributed，on average they were 193.6, 264.3 and 236.9 mu;m respectively,the differences were statistically significant（t=0.40,0.08,0.20;P＜0.05）. The CM,IM and OM average thickness was 194.2,264.9,229.0 mu;m for boys and 189.3,262.5,231.5 mu;m for girls respectively. CM and IM thickness of boys were thicker than those in girls（t=0.15,0.11;P＜0.05）. The CM,IM and OM average thickness was 196.0,265.2,237.5 mu;m for White kids,186.0,262.3,236.5 mu;m for East Asia kids and 19.4,263.7,233.8 mu;m for Central East kids respectively. The CM and IM thickness of White and Central East children were significantly thicker than East Asia children (t=0.12,0.15;Plt;0.05）. There was no difference between these three races in OM thickness（t=0.16,P=0.6）. The IM and OM were thinner with longer axial length (Plt;0.05). The CM,IM and OM thickness was thicker with higher hyperopic degrees (Plt;0.05). Conclusions Macular thickness was normally distributed in six-year-old children and was significantly affected by gender, race, axial length and refraction status.
Objective To verify the changes of optics and refraction of the eyes after retinal detachment surgery with the tamponade of silicone oil in vitreous cavity. Methods The optical calculation was taken as the following by using the parameter of Gullstrand model eye:（1）The refraction of silicone filled eye in non-accommodative status;（2）The refraction of silicone filled eye in non-accommodative status;（3）The aniseikonia analysis when one eye filled with the silicone oil;（4）The IOL power re-calculation． Results （1） Compa red with the normal eye,the eye filled with silicone oil is moved toward high hyperopia of +9．19 D;（2）When corrected,the accommodation amplitude reduced 1.42 D induced by filling silicone oil. Conclusion When eye filled with silicone oil,the change of refractive power tends to be highly hyperopic,the amplitude of accommodation decreased,and the regular IOL power calculation formula is no longer available. (Chin J Ocul Fundus Dis，2000，16：139-212)
Purpose To study the refractive state of silicone oil tamponade eyes. Methods To calculate the theoretical refractive state of eyes with silicone oil based on clinical visual optics and to perform retinoscopy on 48 silicone oil filled eyes with pars plana vitrectomy (PPV) and 45 ones with PPV plus lens ectomy with retinal reposition, and then study theoretical and experimental differences of diopter in silicone oil filled eyes. Results Postoperative diopter of the former increases (+6.26plusmn;1.20)D than preoperative diopter, while that of the latter is (+11.40plusmn;2.22)D. Conclusion Hyperopic changes are found in silicone oil tamponade eyes, and the experimental values are lower than the theoretical ones. This may be helpful in predicting the change of diopter of silicone oil tamponade eyes. (Chin J Ocul Fundus Dis, 2001,17:102-104)
Objective To investigate the refractive shift after combined surgery （phacoemulsification, intraocular lens implantation and vitrectomy） by comparing the difference between the predictive and postoperative refractive power.Methods The clinical data of 44 patients (48 eyes) underwent combined surgery (combined group) and 30 patients (50 eyes) underwent cataract surgery (cataract group) were retrospective analyzed. Combined group was further divided into two sub-groups by the kind of tamponade: balanced salt solution group and gas group. Before surgery, axial length and corneal curvature were measured, and the predictive spherical equivalent (PSE) was calculated. Axial length, corneal curvature and actual spherical equivalent (ASE) were measured in six months after surgery. The differences between PSE and ASE were compared between combined group and cataract group, balanced salt solution group and gas group.Results In combined group,the mean PSE was (-0.10plusmn;0.42) D and ASE was（-1.00plusmn;1.10） D, and the difference was significant（t=6.687, P＜0.05）. Patients underwent combined surgery showed a statistically significant myopic shift compared with those underwent simple cataract surgery （t=-3.792,P＜0.05）, the refractive shift of balanced salt solution group and gas group were (-0.76plusmn;0.89） and （-1.19plusmn;0.94） D respectively, and there was no significant difference（t=-1.530,P＞0.05）.Conclusion Combined surgery of phacoemulsification and vitrectomy tends to shift the actual refractive status to myopia.
ObjectiveTo observe the changes in refractive status of eyes with idiopathic macular hole (IMH) after vitrectomy and phacoemulsification and IOL implantation (combined surgery).MethodsA retrospective clinical study. From January 2016 to June 2019, 51patients (56 eyes) of IMH who underwent combined surgery at the Tianjin Medical University Eye Hospital. were included in the study. Among them, there were 17 males and 34 females with the average age of 66.79±4.33 years. All the affected eyes underwent BCVA, retinoscopy and axial length (AL) measurement. The IOL power was calculated according to the SRK-T formula and the refractive power (predicted value) was predicted. The average BCVA of the affected eye was 0.20±0.13. The average anterior chamber depth was 2.89±0.28 mm. The average △corneal astigmatism was 0.73±0.43 D, the average AL was 22.92±0.70 mm, the average predicted refractive power was 0.10±0.66 D. All the affected eyes underwent standard transciliary flat part three-channel 25G combined surgery. Six months after the operation, the actual value (actual value) of the diopter after the operation was measured with the same equipment and method before the operation. Paired t test was used to compare the difference between the predicted value and the actual value.ResultsSix months after the operation, the actual value of the refractive power was -0.19±0.64 D. Compared with the pre-operative refractive power, the difference was not statistically significant (t=1.665, P=0.102). The difference between the actual value and the predicted value was －0.33±0.81 D.ConclusionsThe refractive status of the IMH eye undergoes myopia drift after combined surgery. The preoperative IOL power budget can be appropriately reserved for +0.3 D hyperopia.
Objective To understand the distribution of outdoor time among children in Shanghai and explore the relationship between different time-period patterns of outdoor time and their effectiveness in preventing and controlling myopia. MethodsThis study is a secondary analysis based on the Shanghai Time Outside to Reduce Myopia study of primary school students aged 6-9 years with complete smartwatch-monitored quantitative data. Data included outdoor time, axial length, cycloplegic refraction, demographic characteristics, and factors related to myopia such as near work. The smartwatch was worn from March 1, to December 31, 2018. Outdoor times were compared and categorized into weekday-dominant and weekend-dominant patterns. Additionally, morning and afternoon outdoor times were analyzed and classified into morning-dominant and afternoon-dominant patterns. Generalized linear models were used to analyze the correlation between different time-period outdoor activity patterns and myopia onset and progression. ResultsDuring the study period, the daily outdoor activity time of children was 84.83 (67.66, 105.47) min/day. Specifically, outdoor activity time was [90.93 (71.66, 113.09) min/d] on weekdays and weekends was [68.14 (51.09, 88.60) min/d], with weekday time significantly higher than weekend time (Z=39.64, P＜0.001). Outdoor activity time in the morning was [46.60 (37.51, 57.88) min/d] and afternoon was [48.99 (38.46, 61.28) min/d], with afternoon time significantly longer than morning (Z=?8.36, P＜0.001). After adjusting for age, sex, residential area, parental myopia, near-work time, and other confounding factors, compared with children with a weekday-dominant outdoor activity pattern, those with a weekend-dominant outdoor activity pattern had a 23% lower risk of myopia onset within one year [odds ratio (OR)=0.769, 95% confidence interval (CI) 0.596-0.993, P=0.044]. Furthermore, compared with children with a morning-dominant outdoor activity pattern, those with an afternoon-dominant outdoor activity pattern was associated with less axial elongation (β=?0.012, 95%CI ?0.023-?0.002, P=0.019) and less myopic progression in refractive error (β=0.029, 95%CI 0.002-0.057, P=0.036). ConclusionWeekend-dominant and afternoon-dominant outdoor activity time patterns are more beneficial for preventing and controlling the onset and progression of myopia.