Femtosecond Laser Assisted Cataract Surgery in Intumescent Cataracts
试验速览
- 阶段
- 4 期
- 状态
- 招募中
- 发起方
- 入组人数
- 425
- 试验地点
- 3
- 主要终点
- To demonstrate lower anterior or posterior capsule tear rate
研究概览
简要总结
Cataract surgery is the most commonly performed operative procedure today with
phacoemulsification being universally accepted as the best method of cataract extraction
(Vajpayee 1999). Phacoemulsification has the advantages of small incision and early visual
rehabilitation. However, phacoemulsification has been considered relatively unsuitable for
challenging case such as hypermature cataracts (Vajpayee 1999) and intumescent white
cataracts (Conrad-Hengerer 2014) because these cases may have increased intracapsular
pressure due to liquefaction of the cortex and a hard or brunescent nucleus underlying an
anterior/posterior cortical opacity. In intumescent cataracts, the structural causes of tensile
weakness were confirmed with ultra-structural analysis of the anterior capsule of the
intumescent cataract. While the analysis showed no increase in thickness, it did indicate
extrusions of basement membrane filaments at the basement membrane epithelial border,
rarefication, perpendicular lucent areas with fibrillary material and lamellae (Hawlina 2011).
These findings represent weak points for capsular stretching, pressure, longitudinal splitting
along the lamellae and tearing to the periphery. Therefore, the most difficult step of cataract
surgery in these cases is the creation of a continuous capsulorhexis without further anterior
capsule complication
The introduction of femtosecond laser for ophthalmic application provides another method for
cutting tissues within the eye. These lasers have been used in ophthalmology for many years.
The most common application is for the creation of corneal flaps but in recent years the
technology has been introduced in cataract surgery. The femtosecond laser assists with all the
key steps in cataract surgery prior to phacoemulsification namely: creation of corneal
incisions, anterior capsulotomy and lens fragmentation (Roberts 2013).
Phacoemulsification requires the creation of a manual
capsulotomy using a surgical cystotome to puncture the capsular bag. This procedure, known
as continuous curvilinear capsulorrhexis (CCC), can be associated with extension of the torn
capsular edge. Such tears weaken and compromise the integrity of the capsule and may lead
to vitreous loss, and the inability to safely place a posterior chamber IOL. The rate of such
complications, about 1%, is not insignificant (Marques 2006).
Phacoemulsification requires the creation of a manual
capsulotomy using a surgical cystotome to puncture the capsular bag. This procedure, known
as continuous curvilinear capsulorrhexis (CCC), can be associated with extension of the torn
capsular edge. Such tears weaken and compromise the integrity of the capsule and may lead
to vitreous loss, and the inability to safely place a posterior chamber IOL. The rate of such
complications, about 1%, is not insignificant (Marques 2006).
The aim of LenSx Laser is to apply the known safety and accuracy of femtosecond lasers,
combined with OCT targeting, to cataract surgery. Considering the features offered by the
LenSx Laser, the following device benefits are balanced against the risks mentioned above.
• For capsulotomy, the LenSx Laser produces anterior capsulotomy whose sizes are
statistically more uniform, accurate, and predictable than those produced by manual
techniques. By providing well-centered and uniform capsulotomy, the placement and
performance of IOL’s is expected to improve.
• For corneal incisions, the benefit of femtosecond laser treatment is well understood.
The LenSx Laser extends these benefits to the creation of uniform, surgeon-chosen
corneal incisions for cataract surgery.
In challenging cases such as patients with intumescent cataracts where visibility of the capsule
can be compromised, this can provide a significant benefit to complete the most difficult step
with minimal risk. In addition, it allows the surgeon to create a customized multi-plane
corneal incision that will be challenging to create manually
研究设计
- 研究类型
- Interventional
- 分配方式
- Not Applicable
- 盲法
- Open Label
入排标准
- 年龄范围
- 21.00 Year(s) 至 99.00 Year(s)（—）
- 性别
- All
入选标准
- •Adults, 21 years of age or older who are willing to undergo cataract surgery
- •Able to lie flat in a supine position
- •Able to understand and sign the Informed Consent Form (ICF)
- •Subjects must present with intumescent white cataract, with a liquid pressurized bag and a milky, liquid cortex.
排除标准
- •Subjects who refuse to sign the informed consent
- •Pregnant or lactating mothers
- •Corneal disease that precludes application of the cornea or transmission of laser light at 1030 nanometer (nm)wavelength
- •Descemetocele with impending corneal rupture
- •Corneal opacity that would interfere with the laser beam
- •Presence of blood or other material in the anterior chamber
- •Hypotony or presence of corneal implant
- •Poorly dilating pupils, such that the iris is not peripheral to the intended diameter for the capsulotomy
- •Condition which would cause inadequate clearance between the intended capsulotomy depth and the endothelium
- •Residual, recurrent, active ocular or eye lid disease, including any corneal abnormality (for example, recurrent corneal erosion, severe basement membrane disease)
- •A history of lens or zonular instability
- •Corneal thickness requirements that are beyond the range of the LenSx Laser system (More than 1200 μ)
- •Subjects who in the opinion of the investigator are not good candidates for the trial
- •Subjects whose postoperative best corrected visual potential is expected to be worse than 20/40 Snellen (0.3 logMAR) at the final study visit.
结局指标
主要结局
To demonstrate lower anterior or posterior capsule tear rate
时间窗: on the day of the surgery (i.e. Visit 00)
with femtosecond laser assisted capsulotomy than standard
时间窗: on the day of the surgery (i.e. Visit 00)
continuous curvilinear capsulorhexis (CCC)
时间窗: on the day of the surgery (i.e. Visit 00)
次要结局
- To demonstrate less operating time in the eye to complete the(entire cataract procedure with the femtosecond laser assisted)