The Role of Transscleral Cyclophotocoagulation in Patients Undergoing a Boston Keratoprosthesis
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 发起方
- 入组人数
- 20
- 试验地点
- 2
- 主要终点
- Cup-to-disc ratio
研究概览
简要总结
The Boston keratoprosthesis (KPro) is a special plastic device that is used to replace a sick cornea (transparent part of the eye, in front of the iris) in order to restore vision in patients who have failed traditional corneal transplants or have a very poor prognosis of success.
Glaucoma is a chronic disease which causes optic nerve damage secondary to high pressure inside the eye and could lead to vision loss in the long term. Glaucoma is highly prevalent in patients who require a KPro and even more after their procedure.
In order to decrease the intra-ocular pressure, surgeons can use multiple eyedrops. Unfortunately, following the KPro surgery, eyedrops lose their efficiency because they are less absorbed by the eye.
The transscleral cyclophotocoagulation (TS-CPC) is a laser treatment used in advanced refractory glaucoma. This laser helps decrease the intra-ocular pressure and have a better control of the disease. There are different methods of laser transmission, including the continuous transmission (G-Probe) and the micro-pulsation method (Micopulse). Given the high prevalence of glaucoma in patients receiving a KPro, the investigators are studying the effect of giving the TS-CPC treatment prophylactically to patients before their Boston keratoprosthesis.
Our hypothesis is that prophylactic TS-CPC will decrease glaucoma progression as well as the risks of developing glaucoma following the Boston keratoprosthesis .
METHOD The investigators aim to recruit twenty (20) patients who are scheduled to receive Boston KPro. Participants will be randomized into two groups: 1) Groupe 1 will receive a prophylactic treatment of transscleral cyclophotocoagulation a G-Probe. 2) Groupe 2 will receive a prophylactic treatment of transscleral cyclophotocoagulation with a micropulse transmission (MicroPulse). The patients will receive their laser treatment by a glaucoma specialist 4 to 8 weeks before their KPro surgery. One week following their laser treatment, the participants will be examined by their glaucoma specialist.
Following their KPro surgery, patients will have a follow-up at day-1, weeks 1 and 2, months 1 and 3, then every 4 to 6 months for 5 years. Additional non-invasive glaucoma tests will be performed twice during the first 3 months following the surgery and will be repeated every 4-6 months. Visual acuity results, the visual field tests and rates of post-operative complications will be compared between the different groups.
详细描述
RATIONAL OF THE STUDY
The Boston keratoprosthesis (KPro) type is an artificial cornea used to restore vision in patients who have failed traditional corneal transplants or have a poor prognosis of success. A number of innovations have improved the postoperative prognosis since its first creation. However, glaucoma is still one of the leading causes of significant vision loss following the surgery, despite the clarity of the anterior segment.
The prevalence of glaucoma in KPro candidates is highly elevated (36-76%). Indeed, pathologies requiring a Boston keratoprosthesis and history of previous ocular surgeries are themselves risk factors for glaucoma. Furthermore, the corneal opacity and irregularities lead to poor visualization of the optic nerve and incorrect intra-ocular pressure (IOP) measurements. Thus, the prevalence of glaucoma preoperatively is most likely underestimated.
Following the KPro, the increase of IOP or the new diagnosis of glaucoma is estimated between 8 and 35% per year. Additionally, the IOP cannot be determined by the traditional tonometry and is estimated by digital palpation. This leads to treatment follow-up being difficult and limited. For those reasons, it is suggested by experts to insert a glaucoma drainage device during the Boston keratoprosthesis surgery for all patients.
In perspective, the transscleral cyclophotocoagulation (TS-CPC) is one of the cyclodestructive procedures used for severe glaucoma. It leads to destruction of the ciliary body epithelium and reduction of aqueous humour production which can reduce the IOP.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Single (Participant)
盲法说明
Patients will not be aware of which type of cyclophotocoagulation treatment they will be allocated.
入排标准
- 年龄范围
- 18 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Adults patients
- •Able to give an informed consent
- •Capable of being followed during the study
- •Candidate for the Boston keratoprosthesis type I
排除标准
- •Patients younger than 18 years old or older than 80 years old
- •Unable to give an informed consent
- •Participating to another interventional glaucoma study
- •Patients who received a glaucoma surgery or procedure (glaucoma drainage device or TS-CPC treatment) 3 months before their initial visit.
- •Unable to wear a therapeutic contact lens secondary to eyelid malformation
- •Severe Ocular surface Disease with keratinization
- •Intra-ocular tumor
- •Terminal Glaucoma
- •Phthisis bulbi
- •Ocular albinism
研究组 & 干预措施
MicroPulse Treatment
Prophylactic transscleral cyclophotocoagulation treatment, delivered by micropulse waves will be given 4-8 weeks before the Boston keratoprosthesis surgery.
干预措施: Transscleral cyclphophotocoagulation using the Micropulse system ( IRIDEX IQ810 Laser systems, Mountain View, CA). (Procedure)
G-Probe Treatment
Prophylactic transscleral cyclophotocoagulation treatment, delivered with a diode laser using the G-Probe device, will be given 4-8 weeks before the Boston keratoprosthesis surgery.
干预措施: G-Probe transscleral cyclphophotocoagulation (Iris Medical Instruments, Montain View, CA) (Procedure)
Historical Cohort
An historical cohort composed of patients who received a Boston keratoprosthesis between january 2017 and january 2019 will be included. Only patients who did not receive any glaucoma treatment 3 months before their surgery will be included. A total of 10 patients will be selected with the goal of matching the preoperative characteristics of the interventional patients.
This group will serve as the control group in our study. Retrospective chart review will be performed for this branch.
结局指标
主要结局
Cup-to-disc ratio
时间窗: 5 years
Rate of progression of the optic nerve cup-to-disc ratio
次要结局
- Goldman visual field loss of 30% or more.(5 years)
- Retinal Nerve Fiber Layer thinning(5 years)
- No light perception(5 years)
- Need of additional glaucoma intervention(5 years)