Treatments & Services
Light Adjustable Lens
Mr Bobby Qureshi was the first surgeon in the world to perform surgery using the Light Adjustable Lens.
What is the Light Adjustable Lens
The Light Adjustable Lens is probably the greatest leap forward in lens implant technology since the first implant was used almost exactly 60 years ago. It is simply the most technologically advanced implant available which can be adjusted after surgery to give the best vision possible for each individual eye without glasses.
Inside every eye is a natural lens which focuses light onto the retina. This lens is transparent and flexible becoming thicker and thinner to focus near and far. In our early forties it loses this ability and becomes more rigid so we need reading glasses to see close, a condition called presbyopia. As it ages further the lens becomes yellow and our vision starts to decline at which stage it is called a cataract.
Almost everyone over the age of 40 or so will be affected by presbyopia or cataracts.
The only treatment for cataracts is surgery where the ageing lens is removed and replaced with an artificial one. Cataract surgery is the commonest operation performed worldwide with over 14 million procedures carried out each year. More than 300,000 are performed within the NHS alone.
An increasing number of people are also opting for clear lens extraction where the lens is removed because it can no longer focus and is replaced with an artificial multifocal or accommodative implant to restore near and distance vision and reduce dependence on reading glasses or varifocals. These are usually compromised by poor intermediate vision and glare when looking at lights.
According to some studies over 70% of people who have lens implants after cataract surgery or clear lens extraction are still left with a degree of long sight, short sight or astigmatism after surgery which means they still need to wear glasses to achieve good vision. This is usually due to preexisting astigmatism or induced astigmatism from the operation, inaccuracy in the biometry measurements taken before surgery to choose the lens strength or the unpredictable effects of wound healing.
For the first time in the history of eye surgery we can correct any residual errors reducing vision without any additional surgical procedures. This is accomplished by adjusting the lens implant after surgery by the safe and non-invasive application of ultraviolet light controlled by a sophisticated computer system. The lens adjustment is so predictable that it is possible to give patients 20/20 normal vision without glasses in healthy eyes.
The lens is implanted using a micro-incision surgical technique where no stitches are required as day case surgery. Approximately 2 weeks after surgery when the wound has healed the patient returns for an adjustment of the lens to achieve the best vision possible. More than one adjustment is possible if required before the lens is ‘locked’. It will never need to be replaced and will last forever. The adjustment to optimize your vision is permanent and it will never again need readjustment.
Light Adjustable Lens Technology
The Light Adjustable Lens silicone was developed from the same material used in modern implants available today worldwide. Millions have been implanted over the last decade and this material has been shown to be completely safe and will not cause a reaction in the eye.
What makes the LAL unique is the incorporation of unique materials called ‘macromers’ which were developed by Calhoun Vision Inc. in the USA led by a team of Nobel Prize winning Scientists.
The macromers are designed to be sensitive to harmless ultraviolet light of a specific wavelength. When this light is shone into the eye the macromers link together in a very controlled and specific way called photopolymerisation.
Mechanism of Action
After the lens has been implanted and the eye has healed -typically at about 2 weeks-, patient’s vision is evaluated. Any adjustment required to perfect the vision is carried out by the digital light delivery device which is designed to deliver the exact dose and profile of light onto the LAL to correct any residual errors.
Light adjustability of the lens is based on the principles of photochemistry and diffusion whereby components incorporated into the lens matrix are photopolymerised on exposure to the UV light.
This means that the light affects the macromers to cause very specific swelling or thinning of the lens implant changing the focus to give the patient the best vision possible for their eye. The process takes less than 2 minutes and can be repeated for further adjustment if required. Once the desired prescription is achieved further UV light is passed through the lens to ‘fix’ it in position to make the adjustment permanent.
Light Adjustable Lens Results
The digital light delivery device calculates the strength and angle of light to make the adjustment to the lens.
Any residual long sight, short sight or astigmatism information is entered into the digital light delivery device and is used to create an adjustment profile which may include an Optimized Wavefront adjustment also.
The adjustment which takes less than 2 minutes usually, modifies the strength of the lens to add or subtract spherical power, eliminate astigmatic error, or add multifocality to achieve the best vision possible at all distances.
Once the appropriate power adjustment is achieved the entire lens is treated using up all the remaining macromer to ‘fix’ the lens power at the desired level.
For further information please see the Calhoun Vision Inc. website.
Correction of residual refractive error in a series of patients treated with the LAL. 93% of eyes achieved within 0.25 D or better of the targeted refractive adjustment. Data courtesy of Calhoun Vision Inc. Dr. Arturo Chayet Codet Vision Institute Tijuana, Mexico
Am I Suitable for the Light Adjustable Lens
- Do you have difficulty reading or seeing things close up?
- Do you have difficulty seeing while driving?
- Does your glasses prescription change frequently?
- Do you wear bifocal or varifocal glasses?
- Do your glasses get in the way of your daily activities?
- Have you had previous laser eye surgery and now have any of the above?
- Have you been told that you have a cataract?
If you can answer ‘yes’ to any of the above, you may have presbyopia or cataracts or both. This also means that your vision is affecting your lifestyle and you may be a candidate for the Light Adjustable Lens.
Light Adjustable Lens FAQ:
- Will it correct my reading vision?
Just as the light adjustable lens can be used to perfect your distance vision, it can also be used to give you good reading vision. Your surgeon will discuss with you the many options that exist for doing so. These include blended micro-monovision as can be achieved with laser eye surgery or bifocal/varifocal vision similar to that achieved by multifocal implants to correct for presbyopia. Unlike all other surgical techniques available for correcting reading vision the light adjustable lens can be adjusted more than once without surgery to give the optimal result for your individual eye
- How long does the lens last?
The lens lasts forever and it never needs to be removed or replaced. The adjustments of the lens power are also permanent and after they have been made to optimize your vision, the lens will never again need readjustment.
- Can any eye surgeon give me the light adjustable lens?
Only expert cataract surgeons who have the approved equipment and are specially trained in the insertion and adjustment of the Calhoun Vision light adjustable lens can offer it to their patients. The London Eye Hospital performed the first Light Adjustable Lens implant in the UK and it remains the centre of excellence in the World.
- What are the risks?
As with any surgical procedure there are risks and the results cannot be guaranteed. The risks are very similar to cataract surgery or clear lens extraction. During the adjustment phase some patients experience transient fluctuating vision for about 24 hours. After the ‘lock in’ treatment some patients experience a mild red tint to their vision which again is transient and lasts for about 24 hours.
Conditions related to this treatment:
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