Intra Ocular Lens Implants (IOL) Consultation and Treatment
- For a minority of patients an intraocular lens implant may be the most appropriate solution for vision enhancement as not everyone is eligible for laser vision correction. This may either be because of extreme refractive error (short sight, long sight and/or astigmatism), unusual corneal findings or other eye health concerns (e.g. cataract).
- For such patients another good alternative to laser vision correction is the option of surgically implanting an Intra Ocular Lens (IOL) inside the eye to improve vision in order to reduce dependence on glasses and/or contact lenses.
- Inevitably, for some patients there may be some overlap as to whether a laser procedure or implantation of an intra ocular lens inside the eye is the method of choice. Our highly experienced team will advise at the time of consultation.
What is an Intra Ocular Lens?
The ARTISAN lens is the most commonly used phakic Intra Ocular Lens worldwide and has a long and successful history. These implantable contact lenses can be used to correct short-sight (from -3D to -23D) and long-sight (from +1D to +12D). Toric ARTISAN lenses can be used when there are higher degrees of astigmatism needing correction.
Advantages of the ARTISAN lens include:
- Potentially reversible
- Quick visual recovery
- Good accuracy of vision correction
- Good quality of vision correction
- No change in the ease of contact lens correction post-op, should this be needed
- Possibility of adjustment of the final optical outcome by laser treatment (Bioptics)
- Maintains accommodation in younger patients
Potential risks of ARTISAN lens surgery include the possibility of infection. It is for this reason that we choose to treat each eye on separate occasions with an appropriate interval of 2 weeks between treatments. There is also a small possibility of damage to structures within the eye that could lead to glaucoma, inflammation of the iris (uveitis), retinal complications, corneal decompensation or cataract. Ultimately, the ARTISAN lens may need to be removed from the eye. For these reasons we always advise patients to have long-term follow-up review appointments.
If you elect for treatment, an interval of approximately 4-6 weeks is required in order to receive the custom made lenses to the correct specification.
The procedure is performed in a specialist, sterile theatre and takes about 20 minutes. A local anaesthetic injection and anaesthetic drops are used to numb the eye. You will not therefore feel any pain. Drops to constrict the pupil are also used. A small incision is made at the edge of the cornea through which the ARTISAN lens is inserted and then carefully clipped to the iris tissue. Sutures are used to close the wound.
After intraocular lens treatment you are able to go home but it is essential that you are accompanied. The treated eye will be patched and you will be given instructions for use of eye drops to prevent infection and help healing. You should notice improvement in your vision by the next day, although the final optical outcome will settle further with time. An appointment will be made for one week after treatment when specific aftercare schedules are decided. You should be able to drive and return back to work within a few days of the procedure. Bear in mind however, that your vision will be unbalanced during the interval between the treatment of each eye.
Over the past few years the ARTIFLEX lens has been developed from an earlier lens design called ARTISAN. ARTIFLEX lenses are made from a combination of an ultraviolet absorbing Polysiloxane optic, and rigid haptics (the part that attaches the lens to the iris) made from Perspex CQ UV (polymethylmethacrylate - PMMA). These lenses can be used to correct myopia (from -2D to -14.5D). The potential advantage of using a flexible lens is that it can be inserted through a much smaller incision and therefore better control post-op astigmatism.
Further details of the ARTISAN/ARTIFLEX lens can be found by visiting their website.
Intra Ocular Lenses (STAAR ICLs)
Over the past few years intraocular 'implantable contact lenses' have been available. STAAR Implantable Contact Lenses are made partly from collagen - the fibre that is the basic building block of the eye. At present, there is only fairly short-term follow-up data available on patients who have had these lenses inserted, but the biocompatibilty of the Implantable Contact Lens seems good. Implantable Contact Lenses can be used to correct both short-sight (from -3D to -18D) and long-sight (from +1.5D to +18 D). A new toric Implantable Contact Lens to correct astigmatism has recently been introduced.
Unlike the Artisan lens, the STAAR Implantable Contact Lens is placed into the eye via a very small incision at the edge of the cornea and is then positioned behind the iris and in front of the natural crystalline lens of the eye.
The insertion of the Implantable Contact Lens is also generally carried out under local anaesthetic. Drops are put into the eye to dilate the pupil and anaesthetise the cornea. A small incision (3mm) is made at the edge of the cornea and the Implantable Contact Lens is injected into the eye and carefully placed over the natural lens.
A drug solution is then injected into the eye to constrict the pupil. After the operation antibiotic drops are given to help prevent infection and steroid drops to suppress inflammation. Visual recovery is rapid, with functional vision virtually straight away and stabilisation of refraction within a few weeks.
The majority of lens implants used are of fixed focus (monofocal), but there are also multifocal implants which give vision for both distant and near objects. However, if monofocal lenses are implanted in both eyes with one eye left a little short-sighted, a similar range of vision can be achieved.
In people who have a significant amount of astigmatism, special toric (aspherical) intraocular lenses may be required to achieve the desired optical outcome, or incisions can be made in the cornea at the time of surgery in order to reduce the astigmatism (astigmatic keratotomy). Alternatively the surgery can be followed by laser surgery to the cornea (e.g. LASIK), to correct the astigmatism.
The phakoemulsification instrument has a small probe connected to an ultrasonic transducer. The ultrasonic vibrations fragment the lens matter and the emulsified fragments are then aspirated in a flow of saline solution. Once the lens matter has been removed the intraocular lens implant is introduced through the same small incision. Made from deformable plastic, the implant is rolled or folded up and injected into the eye. Inside the capsular membrane (remnants of the natural lens), the lens implant unfolds and its optical part is held centrally behind the pupil by supporting loops or plates (haptics).
Intraocular Lens Implant Complications
Occasionally the function of the retina can be impaired by the lens extraction surgery - for example central visual function may be permanently impaired by leakage of fluid into the retinal tissue (cystoid macular oedema). Lens extraction surgery can lead to the vitreous jelly breaking away from the back of the eye (posterior vitreous detachment), with an increase of 'floaters' in the vision. A proportion of patients suffering posterior vitreous detachment go on to develop retinal detachment, which if left untreated can cause irreversible visual loss. High myopes are at increased risk of vitreous and retinal detachment anyway, and there is no doubt that lens extraction is associated with an increased incidence of these problems post-operatively.
Treatment planning and recovery is similar to that described in the earlier section on phakic IOLs.
When the problem arises it is simply remedied by the use of a YAG laser. This invisible infra-red laser beam is focused on to the capsular membrane and vaporises the tissue - so clearing the optical path for light rays to reach the back of the eye. A YAG capsulotomy takes only a few minutes to perform, is entirely painless, and ensures that the visual pathway remains clear of capsular membrane indefinitely.