Laser Lens Replacement
This vision correction option – Laser Lens Replacement involves replacement of the natural lens inside the eye with a high performance lens implant. Trifocal lenses and “Extended Depth of Focus” (EDOF) lenses reliably provides independence from distance, intermediate and near vision glasses.
Laser Lens Replacement (LLR) is also known by other terms such as Natural Lens Replacement (NLR), Refractive Lens Exchange (RLE) and Presbyopia Lens Exchange (PRELEX). In an attempt to “demedicalise” the procedure, brand names such as Clarivu™ or NuVu have been used.
New developments such as the Victus femtosecond introduced to the UK by Centre for Sight in 2012 and more recently another laser CAPSULaser improves procedure safety and outcome by adding a whole new level of precision. Centre for Sight is amongst UK’s most experienced centres providing Laser Lens Replacement or Laser Lens Exchange vision correction.
What is Laser Lens Replacement (LLR)?
Behind the pupil in the eye is a lens that is used for fine focusing. With advancing age, the lens becomes harder and stops moving, which results in the need for reading glasses. With time the same lens becomes cloudy and eventually affects the ability to see, this is then called a cataract.
Laser lens replacement is similar to cataract surgery in that the dysfunctional lens is removed and replaced with a sophisticated intraocular lens implant measured specifically to suit each eye. There are several different types of intraocular lenses available at Centre for Sight.
The only difference is a laser is used (rather than a manual technique) to assist the process in Laser Lens Replacement / Exchange and is performed in this manner in 100% of cases at Centre for Sight.
The aim of the surgeon is to provide spectacle independence and to accomplish this a phenomenal level of accuracy is required. The procedure is achieved through an incision measuring just 1.8mm across, with the most critical portion of the surgery performed by laser.
Why Lens Replacement?
The natural crystalline lens in the eye becomes harder with advancing age and in turn fails to change shape adequately to alter focus for near. A change in shape is necessary when looking at near objects e.g. reading a book or iPad. The natural lens functions inadequately and the condition is termed by some as “Dysfunctional Lens Syndrome” (DLS). The crystalline lens becomes progressively harder and in turn near focus deteriorates further with advancing age. Reading glasses which become progressively stronger are needed to be able to see. This condition is also called Presbyopia.
In the interests of transparency and to avoid misleading our patients, at Centre for Sight we as doctors prefer to use commonly used medical terminology rather than confusing brand names (such as Clarivu and NuVu).
“Replacement of the poorly functioning natural lens with a high performance lens implant can result in complete spectacle independence!”
What types of lenses are used in Laser Lens Replacement?
Who is suitable for Laser Lens Replacement?
Generally over the age of 50 with any level of hyperopic (farsighted) and 55 with any level of myopia (short sight) and astigmatism.
Those who have cataracts may also be suitable for high performance trifocal lenses.
To be suitable for multifocal lenses, eye health has to be good with no identified problems that can affect lens performance. Those with macular degeneration or visual field loss from glaucoma for instance will not be suitable for multifocals. Additionally lens replacement is not suitable for those with diabetes.
Safety is paramount
At Centre for Sight, we are very selective about those who are eligible. Safety is our number one priority and we make our decisions based on scientific evidence, delaying (and first treating where appropriate) or declining those who might be at increased risk.
What alternative procedures are there to Laser Lens Replacement?
Laser vision correction
Procedures which include LASIK (Laser in situ Keratomileusis) or Photorefractive Keratectomy (PRK), work by changing the shape of the cornea and therefore do not involve a lens implant.
Phakic Intraocular Lenses
These are lens implants inserted into the eye without removal of the natural lens.
Both the above options are better for those under the age of 50, who still have clear lenses and good quality of vision with glasses or contact lenses. Both laser vision correction and Phakic intraocular lenses are able to reliably correct one point of focus and usually distance, which means those in their mid-forties might still need to wear reading glasses afterwards. There are options for extending depth of focus and providing the ability to read and include “Monovision” and in the case of laser eye surgery “Supracor Lasik”.
Monovision is a technique whereby the non-dominant eye is planned for near vision and the dominant eye for distance. This means both eyes do not see equally at distance and near, however with both eyes open a good depth of focus is achievable. This is not suitable for everyone and a contact lens trial using this scenario is advised prior to undergoing the procedure. Some may already be using this method with their contacts.
This is a Lasik procedure where the cornea is made to be multifocal. As there is a period of adjustment and adaptation, only the non-dominant eye is treated. More information on Supracor Lasik can be found https://www.centreforsight.com/treatments/laser-eye-surgery/supracor-lasik
Lasers replace the Human hand.
Medical Lasers are known to be highly precise improving the safety of surgery as well as predictability by decreasing the number of variables. By employing the use of Victus Laser and CAPSULaser during a critical component of the procedure (the creation of a round and complete opening in the lens capsule) we are able to offer patients highly precise and reliable procedure to a considerable level of accuracy. With this level of perfection, patients can benefit from even safer Cataract/lens surgery and more predictable surgical outcomes than ever before.
Such lasers have replaced the following surgical components previously performed by a steady hand and scalpel, affording results which are readily reproducible eye to eye:
- Micro-incisions, which when performed by laser can be constructed to be watertight
- Creation of a precise and perfectly circular opening in the lens capsule, allowing the clouded lens to be safely accessed and removed
- In eyes with harder cataracts, a laser can be used to fragment/destruct the cataract, facilitating easier removal
- Treatment of astigmatism during cataract surgery through limbal relaxing microincisions
The laser provides online cross sectional microscopic imaging (OCT scan), very much like an online MRI which is used to guide location of the laser treatment within the eye with considerable accuracy.
Centre for Sight is home to the 3rd Victus laser worldwide, installed here in April 2012 and upgraded to the latest iteration. The Centre is proud to serve as a reference site for the manufacturers of lasers for cataract surgery (Technolas Perfect Vision / Bausch and Lomb and CAPSULaser, Excellens) with the medical director serving as medical monitor to Bausch and Lomb lasers. The unique manner in which we perform laser lens surgery has attracted fellow eye surgeons from the United States, Canada and Europe.
Advancing surgery through innovation – Centre for Sight develops new technique!
“Quicker removal is safer for the eye…”
A pioneering method of lens removal invented by Centre for Sight surgeons called “Translenticular Hydrodissection” has significantly reduced the length of time required to perform cataract surgery. As quicker removal reduces the chance of bacterial infection, this has led to a corresponding increase in safety. Receiving great acclaim from international surgeons, this technique by Sheraz Daya was presented at the European Society of Cataract Surgery Milan 2012 and American Society of Cataract and Refractive Surgery (ASCRS) Chicago 2013, with a video demonstrating the method winning an “Oscar” at the ASCRS film festival.
This method requires a device called the “Daya Trans-Lens Hydrodissection Cannula”, which is now commercially available from international company Bausch + Lomb who collaborated with Centre for Sight to develop the technique.
Use of all these lasers makes the operating theatre look like a scene out of Star Trek!
Process for undergoing Laser Lens Replacement
At Centre for Sight a thorough preoperative consultation will be conducted by the surgeon who will carry out their procedure. The surgeon is supported by a team of highly trained technicians who perform a minimum set of investigations and measurements. Based on initial findings, additional investigations may be required to further evaluate the eyes as necessary. During the process, the technicians and optometrists are in constant contact with and directed by the Ophthalmic Consultant. Once this has been accomplished the patient will be seen and counseled by the Consultant.
The consultation at Centre for Sight routinely involves evaluation of vision and refraction (eye testing), contrast sensitivity, corneal mapping, a check of the overall eye aberrations and the contribution made by the cornea and the lens within the eye.
A dry eye test (Schirmer’s test) is also performed as well as a pressure check (Tonometry) and corneal thickness evaluation (Pachymetry).
A scan of the retina and optic nerve (Ocular coherence tomography) to check the health of the back of the eye and rule out any conditions that may adversely affect the outcome of LLR. The eyes are dilated and a wide-field retinal scan is performed followed by an evaluation by the Consultant. During the process, you will have a chance to watch schematic videos about the procedure, the lenses used and what to expect.
Additionally, you will be provided with a copy of the consent form to read, as this may generate questions which can be answered by the Consultant. The Consultant will look through all the data provided and also perform a thorough evaluation of the front and back of each eye and consider suitability of the procedure. Your Consultant will discuss the overall findings and outline any special considerations specific to you and your eyes and if not suitable will indicate why.
Following the consultation you will be provided a summary of the consultation, as well as the costs of the procedure for you to consider.
The Laser Lens Replacement (LLR) Procedure
The procedure is typically performed under drop anaesthetic. At Centre for Sight most patients opt to have intravenous sedation which involves insertion of a venous cannula and periodic injection of sedatives to keep you well relaxed. Your pupils will be dilated with a series of eye drops and possibly with a medicine pellet under your lower lid. You will also receive strong antibiotic eye drops to kill bacteria and prevent infection.
You will be brought in to the operating theatre and asked to lie down on the bed attached to the laser. The surgeon looking down a microscope will attach a suction ring to the eye, which itself will be attached to the laser. You might have a sensation of pressure. The laser portion process takes between 1 – 2 minutes and involves making an opening in the lens capsule, fragmenting the lens and in some cases making a corneal incision for the correction of astigmatism.
Once accomplished, the laser bed is rotated under another microscope and surgery continues. A sticky plastic drape is placed on the eye after the surrounding skin has been disinfected with an iodine preparation. An eyelid clip is used to keep the eyelids open and the surgeon will perform the remainder of the operation through an opening of less than 2.0mm!
The fragmented lens is removed with another sophisticated machine, followed by which the lens is implanted and once centered and the gel device removed, antibiotics are instilled to prevent infection followed by the eye being patched and a protective shield placed. The other eye is planned to be treated within a few days to a week afterwards.
Surgery on both eyes
Surgery on both eyes is sometimes performed where clinically appropriate. Patients suitable for surgery on both eyes are usually non-complex “middle of the road” cases. At Centre for Sight to ensure maximal safety, each eye is treated independently with different batch numbers of devices and medicines for each eye, as well as instruments that have had different sterilization cycles.
If both eyes are treated on the same day, for practical reasons the eyes are not patched and instead goggles on an elastic band are placed to protect the eyes. Patients are advised to go home and keep their eyes closed and allow them to settle for at least 4 hours. Eye drops are also commenced on the same day and patients must be seen in consultation the following day.
You will have some time to recover following surgery and when ready you will be served a light snack. You will be given a small toiletry bag containing your medications and instructions on their use. You will then be able to go home and we suggest you get plenty of rest that day.
The following day, you should take off your shield and patch. Preserve the shield in case you are instructed to use this at bedtime. Commence your drops as instructed remembering to close your eyes for 5 minutes by the clock before adding the next drop. You may have an appointment to be seen that day or a day or two later. If you are not seen the next day, someone from Centre for Sight will contact you to ensure you are making good progress.
The good news is visual recovery is typically very quick with many patients obtaining excellent vision the day following surgery. Sometimes vision is blurred for one or two days for a variety of reasons and this might be the case if the cataract was particularly hard.
A high performance lens like a trifocal lens implant provides the ability to read without glasses. A monofocal lens corrected for distance vision often results in poor near vision easily remedied by a temporary pair of off the shelf reading glasses.
What to expect after surgery
When one eye is treated at a time, often patients will report the following day that their vision in the treated eye is not quite as good as expected. This is often the case in those who were previously farsighted and can find that distance vision is blurred. This happens because the eye muscles which are trying to focus in the untreated eye, result in the implant being pushed forward making the patient shortsighted. With trifocal lenses, we emphasise preoperatively that it is only when both eyes are treated that patients get the benefit from the lenses with no comparative reference points. The eyes see similarly and vision improves rapidly each day. Previously shortsighted patients often report reading is not as good as it used to be, but with adaptation this improves. The brain is able to pick up the information that it needs and make use of this.
Visual side effects
Initially halos around headlights enough to interfere with the ability to drive comfortably affects 10% of patients, but improves in all patients with time. With adaptation, the brain is able to suppress unwanted information and patients report noticing a reduction in the size of the halos over the next 6 to 12 weeks, eventually disappearing or being just a nuisance. A few patients take longer to adapt (12 to 18 months). In the worst case scenario the implant can be replaced with a monofocal lens, which will have the consequence of reducing the depth of focus and result in the need for glasses.
We check for dry eye before surgery and this is treated if found to be significant. Those with marked tear surface abnormalities are not suitable for multifocal lenses. The abnormal surface can affect the performance of the lenses and cause fluctuation in vision. This condition can be treated in advance and once better, patients can be considered for multifocal lenses. Dry eye after surgery can occur as a result of a) no longer wearing glasses or contact lenses and being exposed to the elements or more commonly b) toxicity from the eye drops which are at a high concentration in order to penetrate and enter the eye. Preservatives in drops are also a contributory factor. Dry eye symptoms and effects do improve a few weeks after the course of eye drops has been completed.
Reading and intermediate vision
Trifocal lenses distribute light energy to three points of focus. The majority (60% or more is for distance and the remainder for intermediate and near. Also some trifocals have more energy for near concentrated in the centre of the lens, as pupils typically constrict when one reads. However in dim light, the pupils can dilate and thus affect reading performance, so reading menus in a dimly lit restaurant might be problematic. Using a light to illuminate the object should help. The ability to see at intermediate (computer monitors) can in some patients take time (6 to 12 weeks) and again this is to do with adaptation. The brain adapts and uses the information that is being transmitted from the retina.
1. Refractive Surgery. Patient Information from the Royal College of Ophthalmologists. Revised April 2017 RCOphth
2. Corneal inlay implantation for correction of presbyopia. Interventional procedures guidance [IPG455] Published date: April 2013 NICE
3. Daya SM, Nanavaty MA, Espinosa-Lagana MM. Translenticular hydrodissection, lens fragmentation, and influence on ultrasound power in femtosecond laser-assisted cataract surgery and refractive lens exchange. Journal of Cataract and Refractive Surgery. 2014 Jan;40(1):37-43. doi: 10.1016/j.jcrs.2013.07.040. Epub 2013 Nov 22. PubMed
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5. Nanavaty MA, Daya SM. Refractive lens exchange versus Phakic intraocular lenses. Current Opinion in Ophthalmology. 2012 Jan;23(1):54-61. doi: 10.1097/ICU.0b013e32834cd5d1. PubMed
6. Montés-Micó R, Ferrer-Blasco T, Charman WN, Cerviño A, Alfonso JF, Fernández-Vega L. Optical quality of the eye after lens replacement with a pseudo accommodating intraocular lens. Journal of Cataract and Refractive Surgery. 2008 May;34(5):763-8. doi: 10.1016/j.jcrs.2008.01.017. PubMed
Find out more about the types on lenses available at Centre for Sight:
* Clarivu™ is a trademark of Optegra and a brand name used for the procedure Laser Lens Replacement.