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Femtosecond lasers for cataract surgery

Source agency:

NIHR-HSC

Date of Submission:

01/08/2012

Date of Printing:

19/05/2013

Disclaimer:

This report is work in progress and should not be used for external distribution without permission from the originating agency. Users should be aware that reports are based on information available at the time of research and often on a limited literature search.

Technology, Company & Licensing

Technology name:

VICTUS™ Femtosecond Laser Platform and Catalys Precision Laser System

Technology - description:

These femtosecond laser systems are designed to help surgeons make more precise cuts in a targeted area without damaging the surrounding tissues. Femtosecond lasers emit optical pulses of short duration (a femtosecond is one quadrillionth of a second). These ultra-short pulses are too brief to transfer heat or shock to the material being cut.

These femtosecond lasers are combined with an imaging system called optical coherence tomography (OCT). OCT is based on optical reflectivity and is able to produce cross-sectional and three-dimensional (3D) images of an object. This means that the surgeon can visualise the cornea and the lens by creating a 3D scan of the eye. This enables precisely centered shapes and patterns to be cut, at predetermined widths and depths into the capsule. The level of precision of the incisions is greater than that achievable by manual means.

These systems can perform the capsulotomy and lens fragmentation. An advantage of this is that they are able to break the lens into small enough fragments to aspirate it out with less wear and tear to the bag of membranes that contains the fluid, compared to manual techniques. This part of the process also takes less time than the current method.

Company or developer:

Bausch and Lomb/Technolas™ Perfect Vision and OptiMedica

Reason for database entry:

Novel femtosecond laser systems for cataract removal surgery. Femtosecond lasers may help surgeons to be more precise when cutting and may lead to better and safer outcomes for patients.

Technology - stage in early warning process:

Assessment complete

Technology - stage of development:

Other

Licensing, reimbursement and other approval:

The VICTUS™ Femtosecond Laser Platform was CE marked in November 2011, for capsulotomy and lens fragmentation, and launched in the UK shortly after. The Catalys Precision Laser System was CE marked in August 2011 for capsulotomy, and lens fragmentation, and is launched in the UK.

There are two further femtosecond laser systems for cataract surgery: the LensAR Laser System (LensAR) which is FDA approved and not yet CE marked; and the LenSx Laser System (LenSX and Alcon), which is FDA approved, CE marked and is currently marketed only to private (non-NHS) users in the UK.

Technology - type(s):

Device

Technology - use(s):

Therapeutic

Patient Indication & Setting

Patient indications:

Cataract removal surgery.

Disease description and associated mortality and morbidity:

Cataracts are cloudy patches in the eye’s natural lens that develop over time and may lead to blurred eyesight and eventually blindness.

Number of Patients:

Cataracts are the leading cause of impaired vision in the UK and throughout the world. In the UK around 30% of people 65 years and over have visually impairing cataract in one or both eyes. It is estimated that 225,000 new cases of visually impairing cataract can be expected each year, the 5-year cumulative incidence being estimated at 1.1 million new cases among the population aged 65 years and older[1]. There are around 300,000 cataract removals in the UK every year[2].

Technology - specialities(s):

Ophthalmology

Technology - setting(s):

General hospital and ambulatory care, Specialist hospital

Setting - further information:

-

Impact

Alternative and/or complementary technology:

Additive or complementary technology

Current Technology:

The only effective treatment is the surgical removal of the cataract.Cataract surgery involves making a small incision in the front surface of the eye (cornea), followed by an incision in the front of the capsule of the lens itself (called a capsulotomy or anterior capsulorrhexis), which opens up the capsule. An ultrasonic probe is then inserted and high frequency sound energy is used to liquefy or fragment the lens in situ (called phacoemulsification), which is then sucked or aspirated out. This process, though effective, can occasionally cause damage to other nearby structures and lead to future complications. The lens capsule is kept in place so that an artificial intraocular lens (IOL), made of specialised plastic material, can be implanted. The tiny implant is folded so that it can be put into the eye through the same instrument that is used to remove the cataract. Once it reaches the right position, the artificial lens is unfolded so that it sits in the right place inside the lens capsule. Once inside the capsule, the IOL can restore vision

Health Impact:

Femtosecond laser assisted cataract surgery is a novel procedure that may facilitate quicker procedures compared with current techniques. Operating time could be halved and may lead to increased patient throughput eventually (time allowances would need to be made for adequate staff training). Femtosecond lasers systems are designed to provide better centration of the IOL and accurate placement of all incisions to improve patient outcomes including improved long-term vision and to reduce (or potentially eliminate) complications such as postoperative astigmatism.

Diffusion:

A significant potential barrier for adoption in the NHS would be the cost of the femtosecond laser system, which is likely to be significantly more than the current ‘phaco’ machines.

Cost, infrastructure and economic consequences:

The cost of these systems was not avilable for this briefing.

Another potential barrier could be the staff training required, in particular, the learning curve that comes with the introduction of a new technique within a well established practice.

Ethical, social, legal, political and cultural impact:

-

Evidence & Policy

Clinical evidence and safety:

There are currently no published clinical trials comparing femtosecond lasers with current surgical practice in terms of benefits to vision. There is one small completed comparative trial of the VICTUS™ and two completed comparative studies of the Catalys system, which look at technical outcomes and these are described in some detail here.

The measured technical outcomes in the studies described below include ‘circularity’ and ‘centration’. Circularity is where the femtosecond lasers make small holes in the lens capsule usually in a circle, and the holes join up to make a continuous hole in the capsule. Centration is the degree to which the IOL is correctly positioned, which is important as this is the biggest contributor to visual error after cataract surgery. It is thought that improved centration may show long-term improvement in visual acuity and may reduce the rates of PCO.

There is a completed trial to evaluate the safety, efficacy and precision of creating an anterior capsulotomy either by using the VICTUS™ Femtosecond Laser Platform or manual techniques in patients with cataracts. Each study group is comprised of 31 eyes. The primary outcomes include the diameter (intended to be 5.5mm, although the software allows the size to be customised), circularity and centration of the anterior capsulotomy. This study has not yet been published in a peer reviewed journal. The company claim that results have shown creating the capsulotomy with the femtosecond laser was safe and effective, with easier removal of the ruptured lens, compared with manual techniques. Improved centration with the femtosecond technique was recorded compared with the manual group (statistically significant). The deviation from perfect centration in the femtosecond group vs manual was 95±37μm and 160±90μm, respectively (statistically significant). A statistically significant difference in the circularity of the capsulotomy using the femtosecond laser compared with the manual technique was also observed (0.97±0.01 compared with 0.93±0.04, 1.0 equals a perfect circle). The company also report that using the femtosecond laser to perform the anterior capsulotomy resulted in high consistency in diameter. Information supplied by the company.

A study of 39 patients evaluated the Catalys Precision Laser System in creating capsulotomies. The procedure was performed as part of a randomised study of femtosecond laser-assisted cataract surgery vs manual techniques. Laser-assisted surgery was performed in 1 eye of all patients; the fellow eye of 24 patients provided a control for manual cataract surgery. The accuracy of the capsulotomy size, shape, and centration were recorded. Laser-created capsulotomies were more precise in size and shape than those created manually (statistically significant). In the patient eyes, the deviation from the intended diameter of the resected capsule disk was 29μm±26 for the laser technique and 337±258μm for the manual technique. The mean deviation from circularity was 6% and 20%, respectively. The centre of the laser capsulotomies was within 77±47μm of the intended position. All capsulotomies were complete, with no radial nicks or tears. The authors of the study concluded that the femtosecond laser produced capsulotomies that were more precise, accurate, and reproducible than those created with the conventional manual technique[3].

A study of 50 patients underwent femtosecond laser assisted cataract surgery using the Catalys Precision Laser System in one eye, with the fellow eye receiving traditional cataract surgery. Postoperatively, 80% of patients showed small petechial conjunctival haemorrhages (broken capillary blood vessels) and vasodilatation in a ring pattern around the area of the suction contact lens, which resolved by 1 week follow-up. In addition, 38% of laser patients and 70% of traditional cataract surgery patients experienced corneal oedema. Best corrected visual acuity (BCVA) showed a gain of 4.3±3.8 lines in the laser group (n=29) and a gain of 3.5±2.1 lines in the traditional group (n=30), although the difference was not statistically significant[4].

Suitably sized randomised controlled trials with clinical outcomes and with longer follow-up are needed to demonstrate the long-term clinical effectiveness, cost effectiveness and safety of the laser systems in all aspects of the cataract surgery compared with current techniques.

Economic evaluation:

-

Ongoing research:

-

Ongoing or planned HTA:

-

Web link:

 

References and sources:

[1]The Royal College of Ophthalmologists. Cataract Surgery Guidelines. Scientific Department, London. September 2010.
[2]Patient.co.uk. http://www.patient.co.uk/health/Cataracts.htm Accessed 12 April 2012.
[3]Friedman NJ, Palanker DV, Schuele G et al. Femtosecond laser capsulotomy. Journal
Cataract and Refractive Surgery. 2011 Jul;37(7):1189-98
[4]Palanker DV, Blumenkranz MS, Andersen D et al. Femtosecond Laser–Assisted Cataract Surgery with Integrated Optical Coherence Tomography. Science Translational Medicine. 2010: Vol. 2, Issue 58, p. 58ra85.

Notes:

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