Intraocular Lens Power Calculation for Combined Phaco-vitrectomy Procedures: Calculation of a New Constant for Biometry IOL-formulas
试验速览
- 阶段
- 不适用
- 入组人数
- 200
- 试验地点
- 1
- 主要终点
- Refractive prediction error (measured by subjective refraction, in diopters)
研究概览
简要总结
The aim of the study is to evaluate the degree of refractive error postoperatively in combined procedures and to calculate a new constant in order to improve current state of the art biometry calculations.
详细描述
The IOL power calculation in combined phaco-vitrectomy has been performed similar to that in cataract surgery alone. In patients who undergo combined phaco-vitrectomy, deviations in refractive outcomes may be observed because of possible errors in measurement of axial length, changes in the properties of the vitreous cavity after removal of the vitreous, or intraocular tamponade. Most of the previous studies have reported variable degrees of myopic shift after phaco-vitrectomy for diabetic retinopathy, epiretinal membrane, and macular hole. Furthermore, use of intraoperative gas may increase further the risk of anterior displacement of the intraocular lens which may induce a higher myopic shift. However, these publications did not provide any quantification of the spherical deviations nor calculate any specific constant in order to improve currents state of art biometry calculations.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Only
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 99 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Patients who undergo a combined procedure with phacoemulsification and pars plana vitrectomy
排除标准
- •Sulcus fixation of the IOL, sulcus suture of the IOL, or intra-scleral IOL fixation because of intraoperative posterior capsule rupture
- •corneal disease, such as keratoconus, that interfered with refractive results
- •IOL implantation with a toric IOL or multifocal IOL
- •History of previous vitrectomy or corneal transplantation
- •Other coexisting ocular disease such as proliferative diabetic retinopathy, advanced age-related macular degeneration, uveitis, acute retinal necrosis, Coat's disease, proliferative vitreous retinopathy, or trauma
- •Intraocular tamponade using silicon oil
结局指标
主要结局
Refractive prediction error (measured by subjective refraction, in diopters)
时间窗: 6 weeks postoperatively
postoperative actual subjective refraction minus preoperative planned refraction in spherical equivalence (in diopters)
Absolute prediction error (measured by subjective refraction, in diopters)
时间窗: 6 weeks postoperatively
absolute value of the difference between postoperative actual refraction and preoperative planned refraction (in diopters)
Changes in Axial Length (measured by biometry, in milimeters)
时间窗: 6 weeks postoperatively
Change of axial length postoperatively (in milimeter)
Changes in corneal curvature (measured by corneal topography, in diopters)
时间窗: 6 weeks postoperatively
change in corneal curvature (in diopters)
次要结局
未报告次要终点
研究者
Josef Guber
Consultant ophthalmic surgeon
Cantonal Hospital of St. Gallen