ObjectiveTo investigate the potential effect of hyperopia status on subfoveal choroidal thickness (SFCT) in silicone oil (SO)-filled eyes.MethodsThis self-comparative study was conducted in Department of Ophthalmology, Central Theater Command General Hospital. The 50 patients (100 eyes) were collected with unilateral macula-on rhegmatogenous retinal detachment from January 2019 to July 2019, who successfully underwent pars plana vitrectomy (PPV) and SO tamponade. Retinal reattachment was observed after surgery in all patients. One month after PPV, the affected eye was wore soft, contact lenses for 24 hours to correct refractive error (RE), depending on its optometry value. The SFCT of the affected eyes was measured using OCT before and after lenses wear. The fellow eyes also received OCT examination at the same time. T test was used to compare SFCT between SO-filled eyes and fellow eyes.ResultsThe mean RE of the SO-filled eyes was +6.38±1.12 D. The mean SFCT of SO-filled eyes (247.12±17.63 μm) was significantly thinner than that of the fellow eyes (276.32.55±17.63 μm) (P＜0.001). The SFCT of the SO-filled eyes was significantly thinner than fellow eyes, and the difference was statistically significant (t=－3.95, P＜0.001). After lenses wear, the mean SFCT of the SO-filled eyes increased to 276.32±24.86 μm. Compared with before lenses wear, the difference was statistically significant (t=－4.30, P＜0.001). Compared with the fellow eye, the difference was not statistically significant (t=0.05, P＞0.05).ConclusionSFCT reduction in the SO-filled eyes may be due to the hyperopia status caused by SO, which can be reserved by RE correction.
Purpose To investigate the influence of ametropia on stereopsis and its mechanism by using the disparity evoked potential testing. Methods A new set of static random dot stereograms was utilized as a stimulation to elicit the disparity evoked potentials in 21 ametropes and 40 stereo normal subjects. Rezults The P250 wave,which was related to stereoscopic stimulation in ametropes,was recorded in both the ametropes and emetropic stereo normal persons in this series,and the characteristic changes of P250 wave with increasing visual disparity in ametropes were similar to those in normal subjects.The differences of mean amplitudes and latencies of P250 waves between myopes and hyperopes were not significant. Conclusion Ametropia in full correction dose not significanly affect the function of stereopsis. (Chin J Ocul Fundus Dis,1998,14:225-227)
In order to understand how the biomechanical properties of rabbit cornea change over time after corneal ablation, 21 healthy adult rabbits were used in this study, with the left eye as experimental side and the right eye as the control side. Firstly, a lamellar knife was used to remove a portion of the anterior corneal surface tissue (30%~50% of the original corneal thickness) from the left eye of each rabbit, as an animal model simulating corneal refractive surgery. Secondly, postoperative experimental rabbits were kept for one, three, or six months until being euthanized. Strip specimens were produced using their corneas in vitro to perform a uniaxial tensile test with an average loading-unloading rate of approximately 0.16 mm/s. Finally, the visco-hyperelastic material constitutive model was used to fit the data. The results showed that there was a significant difference in the viscoelastic parameters of the corneas between the experimental and the control eyes at the first and third postoperative months. There was a difference in tangential modulus between the experimental and the control eyes at strain levels of 0.02 and 0.05 at the third postoperative month. There was no significant difference in biomechanical parameters between the experimental and the control eyes at the sixth postoperative month. These results indicate that compared with the control eyes, the biomechanical properties of the experimental eyes vary over postoperative time. At the third postoperative month, the ratio of corneal tangential modulus between the experimental and the control eyes significantly increased, and then decreased. This work lays a preliminary foundation for understanding the biomechanical properties of the cornea after corneal refractive surgery based on rapid testing data obtained clinically.
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)
Cataract combined with retinopathy can seriously affect the vision of patients. Vitrectomy combined with one-stage implantation of multi-focal intraocular lens (MIOL) has been paid more and more attention. The application of MIOL shows potential in improving the visual quality of patients, but its effect is affected by many factors, and refractive drift is a key problem to be solved. At present, the research mainly focuses on cataract patients with high myopia, and further research on other types of retinopathy is needed. In the future, multi-center, large-sample, long-term clinical studies and interdisciplinary cooperation are needed to optimize surgical and management programs to enhance the application effect of MIOL in the treatment of retinopathy and improve the quality of life of patients.
Objective To investigate the characteristic of the multifocal visual evoked potentials(MVEP)and the visual function across the visual field in anisometropic amblyopes and isometropic amblyopes. Methods MVEP from 32 anisometropic amblyopic eyes and 31 control eyes were tested. Results In anisometropic amblyopic eyes,the latencies of MVEP were significantly prolonged．The amplitudes of MVEP were significantly attenuated in the central region of the visual field,and these phenomena gradually reduced with the increase of the eccentricity． Conclusion The visual function of anisometropic amblyopic eyes is reduced more significantly in the central region than in the peripheral region of the visual field. (Chin J Ocul Fundus Dis,20000,16:27-29)
Objective To investigate the refractive changes of ocular measurable factors due to scleral buckling surgery. Methods A total of 86 eyes of successful rhegmatogenous retinal detachment with a higher encircling scleral buckle underwent A-scan and keratometer examination before surgery as well as l week,4 and 12 weeks after surgery.The refractive factors included the depth of anterior chamber,thickness of lens,axial length of eye,corneal curvature and refraction of eye were detected pre- and post-operatively. Results Compared with preoperation,the depth of anterior chamber was decreased significantly at the lst,4th and 12th postoperative week(P＜0.05),while no significant change of the axial length of eye was observed.The thickness of lens was increased significantly and the refractive error was myopic shifted at the lst and 4th week after operation(P＜0.05),but no significant change was observed at the 12th postoperative week.Statistically significant difference was also observed in corneal curvature of central axis in the local bucklele;1 quadrant with encircling group between preoperation and the lst and 4th postoperative week. Conclusions With higher encircling scleral buckle,the refractive change after buckling surgery may be caused primarily by the shallowing of anterior chamber and thickening of lens. (Chin J Ocul Fundus Dis, 1999, 15: 227-229)
Purpose To investigate the association between the macular volume and thickness, as assessed by optical coherence tomography (OCT), with refraction state and axial length (AL) in children. Methods A total of 100 normal children whose right eyes were randomly selected were divided into five groups due to their refraction, comprising hyperopia, emmetropia, low myopia, moderate myopia, high myopia. The AL of the eyes was measured by IOL mas ter measuring machine. Then the macular volume and thickness were measured by OCT. Results Children with high myopia have smaller macular volume and thinner parafoveal retinal thickness (especially out-ring macular). The minimum thickness and average thickness of the fovea were not significantly different among the five groups. The macular volume ,total average macular thickness and quadrant-specific macular thickness(except the nasal inner quadrants) were positively associated with refraction and negatively associated with AL, while t here were no correlation between minimum foveal thickness, the average foveal th ickness and refraction or AL. Conclusions In Chinese children, increasing axial length was associated with reduced macular volume and thickness (except the foveal region and the nasal inner quadrant). (Chin J Ocul Fundus Dis,2008,24:114-117)
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.