Effect of Lens Presentation on the Clinical Oculomotor Assessment at Near
试验速览
- 阶段
- 不适用
- 状态
- 撤回
- 发起方
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- Horizontal near vergence ranges
研究概览
简要总结
This study will compare near clinical oculomotor parameters (heterophoria, vergence ranges, AC/A and accommodative findings) measured when lenses and/or prisms are introduced using three different instruments namely: (i) a standard manual phoropter, (ii) an electronic phoropter and (iii) a wearable adaptive refractor (VisionFit).
详细描述
Previous studies have demonstrated differences in a number of near oculomotor parameters [e.g., heterophoria, accommodative convergence to accommodation (AC/A) ratio] when measured in a manual phoropter versus a trial frame. These differences may be due to variations in proximal vergence, differences in head and eye position and restriction of the peripheral visual field. Further, a number of standard clinical oculomotor procedures require the use of Risley rotary prisms. While prism is typically introduced in a smooth, ramp-like fashion with manual phoropters, step changes in prism are created with electronic phoropters. The precise effect of these variations on clinical measurements is unclear. Accordingly, after a routine refractive examination, a standard clinical near assessment (comprising near heterophoria, AC/A ratio, horizontal vergence ranges, amplitude of accommodation and negative and positive relative accommodation) will be carried out on the same individuals through: (i) a standard manual phoropter (American Optical model 11625), (ii) an electronic phoropter (Topcon CV-5000) and (iii) a wearable adaptive refractor (VisionFit). The latter resembles a trial frame mounted on a helmet carrier (similar to a binocular indirect ophthalmoscope headset) but includes adaptive lenses that can be changed electronically.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Diagnostic
入排标准
- 年龄范围
- 18 Years 至 30 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Corrected visual acuity of at least 20/20 (logMAR = 0.0) or better in each eye
排除标准
- •Strabismus, amblyopia, manifest ocular disease.
结局指标
主要结局
Horizontal near vergence ranges
时间窗: approximately 15 minutes
Near base-in and base-out vergence ranges will be measured (in prism diopters) while the subject fixates a near target. Measurements will be expressed in terms of the blur point, break point and recovery measurement .The single set of measurements will be recorded approximately 15 minutes after the start of the trial.
Minus lens amplitude of accommodation
时间窗: approximately 15 minutes
Minus lens amplitude of accommodation (measured in diopters) will be recorded using each of the three lens presentation devices.The single set of measurements will be recorded approximately 15 minutes after the start of the trial.
Near horizontal heterophoria
时间窗: approximately 15 minutes
Near horizontal heterophoria (measured in prism diopters) will be recorded using both the Von Graefe and Modified Thorington techniques using each of the three lens presentation devices. The single set of measurements will be recorded approximately 15 minutes after the start of the trial.
Accommodative convergence to accommodation (AC/A) ratio
时间窗: approximately 15 minutes
The AC/A ratio will be calculated from measurements of near horizontal heterophoria (quantified in prism diopters) will be recorded using the Modified Thorington technique at 3 different accommodative stimulus levels (1.5D, 2.5D and 3.5D). Measurements will be obtained using each of the three lens presentation devices and calculated in units of prism diopter per diopter accommodation.The single set of measurements will be recorded approximately 15 minutes after the start of the trial.
次要结局
- Negative and Positive Relative Accommodation (NRA and PRA)(approximately 15 minutes)