Effect of Centration Compensation on Visual Quality in VisuMax 800 SMILE for Small Kappa Angles: A Randomized Trial
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 224
- 试验地点
- 1
- 主要终点
- Coma aberration
研究概览
简要总结
The goal of this clinical trial is to evaluate the effect of intraoperative kappa-angle compensation on postoperative visual quality in patients undergoing small incision lenticule extraction (SMILE) using the VisuMax 800 platform. The study will enroll patients with myopia and a kappa-angle offset < 0.2 mm.
The main questions it aims to answer are:
Does intraoperative kappa-angle compensation reduce postoperative higher-order aberrations after SMILE? Does kappa-angle compensation improve postoperative visual quality and refractive outcomes compared with no compensation?
Researchers will compare SMILE with intraoperative kappa-angle compensation to SMILE without compensation to determine whether compensation leads to better optical quality and visual performance.
Participants will:
Undergo SMILE surgery with or without intraoperative kappa-angle compensation Complete scheduled postoperative examinations at 1 week, 1 month, 3 months, and 6 months after surgery Receive measurements of visual acuity, refraction, higher-order aberrations, contrast sensitivity, and safety outcomes
详细描述
Angle kappa refers to the offset between the visual axis and the pupil center and may influence the centration of the treatment zone during corneal refractive surgery. Inaccurate centration can lead to decentered ablation and may affect postoperative visual quality, especially higher-order aberrations. With the development of femtosecond laser technology, more precise intraoperative alignment has become possible.
Small incision lenticule extraction (SMILE) is a commonly used corneal refractive procedure with good safety and predictability. The VisuMax 800 system incorporates machine vision-assisted centration guidance, which allows intraoperative adjustment of the treatment center according to the relative position of the corneal vertex and the pupil center. This provides the possibility of performing intraoperative compensation based on the kappa-angle offset.
Previous studies have mainly evaluated centration adjustment in eyes with relatively large kappa-angle offsets and suggested that compensation may improve postoperative optical quality. However, for patients with small offsets, the necessity of intraoperative compensation remains unclear, and prospective randomized clinical trials are limited.
The purpose of this study is to compare the visual outcomes and optical quality after SMILE with or without intraoperative kappa-angle compensation in patients with small kappa-angle offsets.
This study is a single-center, randomized, parallel-group clinical trial. Participants who are suitable for SMILE surgery and have a kappa-angle offset less than 0.2 mm will be enrolled and randomly assigned to receive SMILE with compensation or SMILE without compensation using the VisuMax 800 platform.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Participant, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Patients aged 18 to 40 years with myopia or myopic astigmatism and stable refraction for >=1 year, whose refractive errors fall within the treatable range of and meet the indications for SMILE surgery.
- •Normal corneal morphology and corneal thickness meeting surgical requirements.
- •Preoperative corrected distance visual acuity (CDVA) >= 1.
- •Preoperative synthetic Kappa angle offset measured >= 0.10 mm and < 0.20 mm.
- •Voluntarily agree to undergo SMILE surgery on the VISUMAX 800 platform, understand the randomization scheme, and provide signed informed consent.
排除标准
- •History of prior ocular surgery, significant ocular trauma, or presence of corneal or ocular diseases that may affect the safety of refractive surgery.
- •Severe systemic diseases that may affect ocular healing or surgical safety.
- •Females who are pregnant or lactating.
- •Inability to cooperate as required to complete the procedure or follow-up visits.
研究组 & 干预措施
Non-compensation group
Subjects underwent SMILE surgery on the VisuMax 800 platform. Preoperative offset coordinates (x, y) were measured; however, while preserving the directional sign, no kappa-angle-based laser centration compensation was applied intraoperatively, and the treatment center was set according to the system's default centration method. Except for the difference in compensation strategy, all other surgical procedures and postoperative management were identical to those in the compensation group.
干预措施: Apply no compensation to the Kappa angle (Procedure)
Compensation group
Subjects underwent SMILE surgery on the VisuMax 800 platform. Preoperative offset coordinates (x, y) were measured, and, while preserving the directional sign, a fixed intraoperative laser centration compensation of 0.1 mm was uniformly applied to all eligible study eyes to achieve a quantitative adjustment of the treatment center toward the visual axis. Except for the difference in compensation strategy, all other surgical procedures and postoperative management were identical to those in the non-compensation group.
干预措施: Apply compensation to the Kappa angle. (Procedure)
结局指标
主要结局
Coma aberration
时间窗: 3 months after surgery
Coma aberration measured by wavefront aberrometry to evaluate the effect of intraoperative kappa-angle compensation on postoperative optical quality.
次要结局
- Higher-order aberrations(1 month, 3 months, and 6 months after surgery)
- Optical zone decentration(3 months after surgery)
- Visual acuity(1 month, 3 months, and 6 months after surgery)
- Manifest refraction(1 month, 3 months, and 6 months after surgery)
- Refractive accuracy(1 month, 3 months, and 6 months after surgery)
- Refractive stability(1 month to 6 months after surgery)
- Contrast sensitivity(3 months after surgery)
- Quality of Vision (QoV) score(3 months after surgery)
- Patient satisfaction score(3 months after surgery)
- Adverse events(Up to 6 months after surgery)