Images are focused on the retina by the cornea (the clear part of the front of the eye) and the natural lens (suspended within the eye just behind the pupil). About half the Irish population (50%) requires glasses or contact lenses to focus a clear image of a distant object on the retina (Figure 1).
Short sight (myopia) and long sight (hypermetropia) are often accompanied by an element of uneven focusing power (astigmatism). In this case, the cornea is more rugby ball or egg-shaped than football-shaped. This is represented in your glasses prescription by a second number and an angle (e.g. –4.00D at 80°) indicating the focusing power and orientation of the lens required to correct the astigmatic component of your refractive error.
The younger eye is able to increase focusing power, or accommodate, to see near objects clearly. This flexibility of focus is provided by flexibility in the shape of the natural lens. As we get older, the natural lens becomes less flexible (presbyopia), and the ability to accommodate diminishes. This is why normally sighted people need reading glasses from their mid-forties on. The final component of your glasses prescription describes the reading addition, or the difference between your prescriptions for distance and reading glasses. Typically, this varies from +1.00D in your mid-forties to a maximum level of +3.00D by your early sixties. (Figure 2)
Refractive Surgery (Laser Eye Surgery)
Refractive surgery is not normally performed until the glasses prescription has been stable (no change greater than 0.50D) for 1-2 years. Spectacle prescriptions typically stabilise in the late teens or early twenties for myopic patients (-ve prescriptions), and later for hypermetropic patients (+ve prescriptions) who are able to compensate by accommodation (as in focusing for near vision) whilst younger, and often only become spectacle dependent in mid-life.
Laser eye surgery techniques are available to reduce or eliminate the need for spectacles in most patients with a stable spectacle prescription. For younger patients, good distance vision in both eyes is usually the aim. For patients in the reading glasses age group, a compromise (monovision) in which better distance vision is targeted in one eye and better near vision in the other is commonly employed to minimise spectacle dependence over a range of activities.
Lower refractive errors (in the range +3.50 to -8.00D) are usually corrected using laser surgery techniques (LASIK, LASEK or PRK) to reshape the cornea. Higher errors are corrected using lens implant-based methods (Refractive lens exchange/RLE or Intraocular Collamer lens/ICL implantation). Astigmatism and age are also influential in determining the most appropriate technique. Many patients over 60 are better suited to clear or refractive lens exchange (RLE) than laser eye surgery, particularly if the early signs of cataract (lens opacity) are present.
Laser Eye Surgery Procedures
LASIK (Laser in situ keratomileusis) – range +3.5D to -8D with up to 6D astigmatism.
Principle = wavefront-guided excimer laser corneal reshaping beneath a protective corneal flap which is replaced at the end of surgery (Figure 3).
In LASIK, a femtosecond laser (the Intralase FS60) is used to create a standard size hinged flap of surface corneal tissue. The tissues beneath are then reshaped using a computer-controlled excimer laser before the protective flap is replaced. In essence, the cornea is reshaped without surface damage. Because the surface tissue damage is minimised in LASIK, visual recovery is rapid and virtually pain free.
>> Flap information – a thin flap of surface corneal tissue is formed using a blade-free laser
>> Wavefront guided laser reshaping – the flap is flipped over to allow laser reshaping of the cornea without damage to the surface tissues
>> Flap replacement – the surface tissue flap is repositioned on the reshaped cornea, and normally adheres quickly without stitches
Intralase LASIK Laser Eye Surgery– (all laser / blade-free LASIK)
Prior to 2007, automated mechanical microkeratomes were used to make the flap (like a mini ham slicer used in delicatessens) until bladeless surgery was introduced using femtosecond lasers.
Since 2007, surgeons in the Blackrock Clinic use the Intralase femtosecond laser to create the corneal flap under which the corneal stroma is then reshaped with the Visx excimer laser. Bladeless laser eye surgery has safety advantages over previous techniques and has resulted in far fewer flap-related complications.
LASEK / PRK (Surface laser eye surgery) – range -1D up to -8.0D with up to 6D astigmatism
Principle = wavefront guided excimer laser corneal reshaping of the corneal surface. A skin layer is removed prior to surgery and regenerates in the week after. Recovery time is longer for surface laser eye treatments (LASEK and PRK) but they have safety advantages for patients with thinner corneas. For patients found to have a relatively thin cornea at their initial consultation, surface laser eye treatments such as PRK, or variations such as LASEK, are often the safest options.
In LASEK, an anti-scarring drug is often applied to the corneal surface to reduce haze (loss of corneal clarity) and regression (corneal shape changes during healing which can dilute the effect of treatment). A bandage contact lens is then applied to protect the operated area for a few days whilst the skin layer heals. Eye drops are used to minimize discomfort, but approximately 5-7 days, in which the eyes are relatively sore, light-sensitive and watery is normal. Vision returns over the next few weeks whilst the new skin layer remodels. Although the recovery is slower after LASEK than after LASIK, final visual results are normally equally good 2 months after surgery. (Figure 4).
RLE (Refractive Lens Exchange) – range: myopia/hypermetropia at any level can be treated with RLE
Principle = replacement of the natural lens with an intraocular lens (IOL) delivered through a self-sealing micro-incision which does not affect eyewall strength. Incisional techniques or specialized toric IOLs can be used in tandem with RLE to reduce astigmatism, and multifocal IOLs can be implanted to reduce spectacle dependence for near vision. RLE is identical to modern cataract surgery. The new lens is implanted within the capsule of the natural lens which shrink wraps the implant and stabilises it in the natural position. The natural lens becomes more misty with age, and patients over 60 years old are often more suited to RLE than laser refractive surgery (Figure 5). Complications of this operation are the same as those for cataract surgery.
Wavefront-guided laser eye surgery
Laser eye surgery is based on the microscopic reshaping of the cornea to correct myopia, hypermetropia, and astigmatism. The excimer laser removes tissue with submicron precision and has been used to reshape the cornea in refractive surgery for the last 20 years.
Wavefront scanning aims to take account of optical aberrations in the eye above and beyond myopia, hypermetropia, or astigmatism. These higher-order aberrations are best understood by thinking of your spectacle prescription as an average of the focusing requirements for light rays entering the eye through different points on the eye surface (Figure 7).
If your refraction is, for example, -3.00D, this may be an average of -2.80D for rays entering through the centre of the cornea and -3.20D for rays entering around the edge. A wavefront scan produces a map of the focusing requirement at each point. Information from this scan can be programmed into the excimer laser with the aim of reshaping the cornea to produce sharper vision than glasses. Current wavefront guided laser treatments do not routinely produce better vision than glasses and contact lenses. But they have two benefits over non-wavefront guided treatments:
Wavefront-guided treatments are less likely to result in surgically induced increases in higher-order aberrations (ie the corneal shape produced by a wavefront-guided treatment is closer to the ideal natural shape of the eye).
Wavefront-guided surgery is less likely to cause night vision problems or degradations of other elements of visual performance.
The wavefront scanning and excimer laser refractive surgical system used at the Blackrock Clinic is the latest generation AMO CustomVue System.
Laser Eye Surgery Consultation
Your suitability for laser eye surgery is determined in a refractive surgical consultation. The consultation includes a multi-staged examination of your eyes for which you should allow 1 – 2 hours (some waiting between key stages is inevitable). First, you will see a specialist nurse for scanning of your eyes. You will then see Mr O’Brien to review information from these tests, examine your eyes, and discuss your procedure choice.
Before attending the consultation, you should leave your contact lenses out for:
Gas permeable hard lenses – 2 weeks
Soft lenses – 1 week
Continuous contact lens wear can produce temporary changes in the shape of your cornea. It is important to leave contact lenses out prior to the consultation, as specified above, to ensure that your corneal scanning and refraction tests are accurate.
Wavefront LASIK or LASEK may not be suitable if you have:
Only one good eye
If you have a common condition called amblyopia (a lazy eye), or for any other reason you have one eye in which the vision cannot be improved to a normal level with either glasses or contact lenses, any risk to the vision in your good eye is harder to justify. This issue requires particularly careful consideration if you are reliant upon good vision in one eye only for work or driving.
Ocular surface disease
If you have dry eyes, active blepharitis, or allergic eye disease requiring regular drug treatment, corneal healing after laser eye surgery may be adversely affected.
Corneal disease or abnormality
You will be carefully screened to ensure that you do not have a condition called keratoconus prior to laser treatment. Mild forms of this corneal shape abnormality are relatively common and can predispose to a poor result from laser eye surgery.
Altering the shape of the cornea can affect the accuracy of intraocular pressure measurements and therefore the treatment of glaucoma. But corrections to pressure measurement after laser refractive surgery can be applied where necessary.
Cataract extraction presents an opportunity for refractive correction without laser surgery. An artificial lens is normally implanted in the eye during cataract surgery. The power of this lens can be chosen to correct any pre-existing refractive error. Patients over 50 years old commonly have early-stage cataracts.
Time off work
Treatments are normally performed on a Monday afternoon with initial postoperative review the following day (Tuesday) for LASIK and 3-4 days later for LASEK (Surface treatment). Office-based work is usually no problem from the day after LASIK. For outdoor occupations, professional drivers and patients having LASEK, work can normally be resumed 7 days following treatment.
Laser Eye Surgery in both eyes
Most patients elect to proceed with LASIK in both eyes. LASIK in the second eye can either be done on the same day as the first eye (simultaneous bilateral LASIK) or at any convenient time thereafter (sequential bilateral LASIK). Clinical trials comparing simultaneous and sequential LASIK have shown no difference in safety and outcomes. Having both eyes corrected on the same day has considerable practical advantages, and is the preferred option for the vast majority of patients. Bandage contact lenses and routine drop treatments reduce postoperative discomfort to manageable levels for after surface treatments, and bilateral treatment is now the preferred option for most patients undergoing LASEK.
Monovision – an option normally only considered for patients over 40
Electing to leave one eye relatively myopic (typically a 1.00D to 1.50D under correction) to assist near vision (monovision) is the strategy of maximum spectacle independence for patients in the reading glasses age group (43 years and over). Glasses will still often be required to read fine print comfortably but monovision may delay the onset of spectacle dependence for reading until the mid-fifties or later. Even then, spectacle dependence is decreased for common near vision tasks such as computer work, reading a menu or a price label. Monovision does not work for everyone and may increase spectacle dependence for some distance vision tasks (typically night driving), but the compromise for distance vision is relatively small. If you are in the age group for reading glasses (presbyopia), the pros and cons of monovision will be discussed with you by Mr Paul O’Brien at your refractive surgical consultation. It must be remembered that monovision is a compromise. If the eye corrected for distance is covered then the other eye will have subjectively reduced vision (as it will be left under-corrected purposely to allow unaided reading).
Outcomes and Risks of refractive laser eye surgery
Over 97% of wavefront LASIK patients in the range treated at the Blackrock Clinic are able to see the driving standard or better without glasses after one treatment. Results for surface treatments (e.g. LASEK or PRK) are similar.
Enhancement treatment (retreatment) is highly effective in correcting significant residual refractive errors (>1.00D). Retreatment is carried out in approximately 5-10% of cases. There is no additional charge for retreatments carried out within a year of primary treatment (the need for any retreatment can normally be determined within 6 months of surgery).
Realistic expectations are important. Laser refractive surgery is highly effective in reducing spectacle dependence. At a minimum, you should expect to be able to play sport and socialize comfortably without glasses after treatment; but some patients may still prefer to wear thin glasses for selected distance vision tasks.
Wavefront laser refractive surgery of any type does not routinely deliver above normal vision. Most patients have low-level residual refractive errors after surgery. These refractive errors are at a similar level to those normally found in non-spectacle wearers and do not usually require retreatment.
Vision should otherwise remain stable and good permanently after treatment. Your risk for developing other eye problems should not be altered. Natural variations in the distance spectacle prescription can occur at any age. These are usually small but can be large enough to warrant further treatment in a small percentage of patients (less than 2% in the first 5 years after treatment).
The benefits of laser eye surgery are primarily functional. It is not a cosmetic procedure. Freedom from glasses and contact lenses will enable you to enjoy sport and physical exercise and to pursue a healthy active lifestyle.
Laser eye surgery is real surgery and is performed in an operating theatre in the Blackrock Clinic Hospital. Despite the risks of surgery, large studies have recently reported that this form of surgery has the highest patient satisfaction ratings of any surgery throughout the world. The overall complication rate for LASIK is about 5% (figures for LASEK are similar). Most problems are minor, and almost all complications can be corrected safely without affecting the final visual result. Additional consultations and treatments may be required. There is no charge for any additional treatment required for the correction of complications.
The risks associated with laser eye surgery include the following:
Less than 1 in 1000 patients is left with significant scarring or corneal irregularity requiring a corneal graft or hard contact lens for visual rehabilitation. This level of risk is similar to the cumulative risk of corneal scarring resulting from infection in 5-10 years of contact lens wear.
Large studies indicate a 0.5% decrease of 2 lines of visual acuity. The incidence of severe vision loss is very low and is usually due to infection. A recent study (Ophthalmology 2010) has shown that the risk of corneal infection after refractive surgery is 1 in 2800 cases. Antibiotic eyedrops are used to reduce your risk.
Most complications occur within 1 month of LASIK or LASEK. The risk of long-term loss of corneal shape stability (keratectasia) after LASIK has recently been estimated at less than 1/1000. Current patient selection strategies further reduce this risk. The risk for keratectasia after LASEK is negligible.
Unexpected refractive outcome
Not everyone responds identically to the surgery, leading to under or overcorrection with possible need for enhancement. Enhancement is required in 5-10% of cases and is usually performed 3-12 months after the initial surgery. Younger age and higher prescription glasses are risk factors.
Possible need for glasses
Some patients are not suitable for retreatment and may, therefore, require glasses if they have regression. It can be difficult to fit contact lenses after laser eye surgery in some circumstances due to the flattened central cornea.
This occurs in less than 1% of cases and includes a free flap, buttonhole or incomplete flap and may require abandoning the procedure and rescheduling surgery six months later. This risk has been greatly reduced by using the laser (Intralase) to cut the flap.
Flap striae of wrinkles occur rarely but may necessitate refloating the flap. Rarely there may be noninfectious inflammation under the flap called diffuse lamellar keratitis (1%), which commonly responds well to topical steroids.
Epithelial ingrowth occurs when epithelial cells are implanted or migrate under the stromal flap after LASIK. Small degrees (<1 mm) of peripheral epithelial ingrowth is not uncommon. Larger areas of ingrowth occur approximately 1% of the time after primary LASIK and up to several times that amount after enhancements where the flap was lifted. It is generally detected within 2 months of surgery and may disappear, remain the same, or continue to worsen. Epithelial ingrowth can cause several problems including flap necrosis, irregular astigmatism, and scarring, all of which may result in decreased vision. There are a variety of methods to manage epithelial ingrowth including observation, lifting of the flap lift and rubbing out the epithelial cells.
Glare and halos
Not common with larger treatment zones and newer generation lasers. If this occurs it is frequently a temporary phenomenon and settles by week 4.
Transient light sensitivity
Following laser, the eyes may become abnormally light-sensitive (1% of cases). Topical eyedrops can help alleviate this symptom. Sunglass wear is advised in the early postoperative phase (1-2 weeks).
This is the inherent need for reading glasses as the ability of the eye to focus up close is progressively lost as one gets older. In general, people need reading glasses aged 45-50 years. This surgery does not eliminate the need for reading glasses.
Almost everyone has dry eyes following LASIK surgery, which is only temporary in the majority. All patients are prescribed lubricant eyedrops for 1-2 months following surgery and if dryness persists temporary punctual plugs are utilised. If one does not have significantly dry eyes before surgery it is highly unlikely that postoperative dryness will persist.
The preoperative screening exam will usually identify if you are at risk of double vision.
This is of no visual significance and resolves in 2-3 weeks.
The need for glasses can be reduced considerably or, in many cases, corrected entirely by refractive surgery. LASIK, the dominant contemporary technique, is based on laser reshaping of the cornea. This works really well for many patients, but higher corrections require a greater depth of tissue removal, and there is a limit to the amount of corneal tissue that can be removed safely. So for many patients with higher refractive errors (typically -8.00D and above; +4.00D and above), alternative techniques based on lens implantation are more suitable. A number of different lens implants have been developed for correcting high refractive errors. The Implantable Collamer Lens (ICL) is the safest of these.
In high myopia (>-8.00D) the eye has too much focusing power. Without glasses, light from objects further than 1/8th of a metre away from the eye is focused in front of the retina, forming a blurred image.
The ICL for high myopia (-8.00D and above) is a negative lens, which acts to neutralise the excessive focusing power of the eye allowing clear vision in the distance.
The ICL for hypermetropia does the reverse. It is a positive lens that acts to neutralise insufficient focusing power. Astigmatism (uneven focusing power) is corrected using the toric ICL (TCL).
ICL surgery is based on tried and tested techniques for lens implantation developed in cataract surgery. A 3mm self-sealing valve type wound, which does not require sutures and does not diminish the strength of the eye wall, is used to enter the eye. The flexible ICL is then folded into an injecting device and injected through this wound. Specialised instruments are used to position the lens correctly, between the natural lens and the iris. The ICL effectively builds your contact lens or spectacle correction into the eye.
The ICL is made from a soft biocompatible gel material based on natural collagen. Because the lens is implanted within the eye, no cleaning is required. The first ICL was implanted in 1993. Since then, over 300,000 ICLs have been implanted.
The operation can be performed under either local or general anaesthetic as a day case procedure (you do not need to stay in hospital overnight). You can normally see quite well within 2 days of the surgery. The eyes are operated on two weeks apart. After care is simple: 2 sets of eye-drops 4x per day for 3 weeks. Surgery is normally performed on a Friday and a return to most types of work is usually possible by the following Monday.
85% of patients with no other eye problems are able to see at the level of a normal non-spectacle wearer (6/6 or 20/20) after ICL (or TCL) implantation. Over 95% are able to see at the driving standard or better, and simple enhancement procedures are available for many patients who are not initially at this level. The quality of vision for most patients is similar to that obtained in contact lenses. For patients with significant astigmatism, it is often better (TCLs provide better stability of vision than soft toric contact lenses).
Some patients with high myopia or hypermetropia do not see at the driving standard in one or both eyes even with spectacles on. This is the pre-existing limitation on vision, called amblyopia (‘lazy eyes’), is usually a consequence of poor focus as a very young child when the connections with the visual areas of the brain are being formed. Pre-operative testing will determine whether you are in this group. Whilst ICL implantation can dramatically reduce spectacle dependence for patients with additional eye problems such as amblyopia, it is important to understand that surgery may not allow you to see further down the testing chart than you can see in your spectacles or contact lenses before the surgery.
A realistic aim is to have vision that is good enough to participate in most sports and to socialise without glasses on. Many patients are spectacle free after surgery, but spectacles may still be required for some purposes – particularly for reading in patients over 40 years of age.
Approximately 20% of patients (1 in 5) notice increased light scatter (haloes around lights, starburst rays shining around point light sources) at nights. These symptoms tend to diminish with time, but night driving ability may be affected. ICL implantation is reversible: the implants can be removed if necessary. Intolerable light scatter symptoms are uncommon, however, and reversal of ICL implantation is rarely requested.
ICLs do not cause discomfort and are not visible in the eye.
>> Permanent serious loss of sight < 1/1000
Because ICL surgery involves placing an artificial lens inside the eye, there is a risk of introducing infection, which may result in a serious loss of sight. Current research indicates that the risk of endophthalmitis (infection inside the eye) after ICL implantation is approximately 1/5000. An array of precautions is taken to prevent infection, and we aim to ensure that one eye is recovering without any signs of infection before performing surgery on the other. This is the reason why lens implantation operations, unlike eye surface reshaping operations such as LASIK, are not performed on both eyes on the same day. We normally wait for a minimum period of one week (and usually two weeks) between ICL operations for the right and left eye.
>> Cataract = 1/50
Contact between the natural lens and the ICL may, in some cases, cause the natural lens to lose clarity. If lens opacification progresses to interfere with vision, the cloudy lens is called a cataract. Recent studies suggest that the chances of developing a cataract within 5 years of ICL surgery are less than 2%, and that cataract formation is rare in ICL recipients under 40 years of age. Pre-clinical studies indicate that the risk of cataract may be even lower for the latest (v4c) version of the ICL, which acts to maintain normal fluid flow over the natural lens after implantation. But the long-term risk of cataract formation after ICL implantation remains unquantified. Cataract surgery is common in later life anyway (1 in 3 people have cataract surgery at some stage) and high myopia is an independent risk factor for cataract formation. But it is probably safest to assume that ICL implantation may bring forward the age at which you might require cataract surgery. ICL implantation does not make future cataract surgery more complicated. ICL removal can be combined easily with cataract surgery in which a new artificial lens, equivalent in focussing power to the ICL, is implanted to take the place of the natural lens. Good distance vision is normally maintained.
>> Revision surgery = 1/50
One of the key advantages of ICL surgery is reversibility. If any signs of an adverse reaction to ICL implantation are observed at review visits, the ICL can be removed relatively easily. More commonly, revision surgery involves replacing one ICL with a smaller or larger lens to improve the fit in the eye or repositioning the ICL within the eye. If revision surgery is required, there is no additional charge. The operation feels much the same as the original implantation, with a similar, rapid recovery.
>> Retinal detachment
Retinal detachment is a sight-threatening problem, which is more common in people with high myopia. Cataract surgery, in which the natural lens is replaced with a new lens, is known to increase the risk of retinal detachment in highly myopic patients. ICL implantation is less invasive and does not increase the risk of retinal detachment above the background rate (the rate of retinal detachment in highly myopic patients who have not had surgery).
Retinal detachment is a condition you should be aware of if you have high myopia regardless of whether or not you have refractive surgery. Danger signs are flashing lights within the eye, a sudden new shower of floaters, or the sense that part of your visual field is shadowed or missing (flashes, floaters and field loss). Myopic patients experiencing any of these changes in vision should seek an urgent eye examination. 9 out of 10 retinal detachments are successfully repaired at the first attempt, and the likelihood of success is increased by catching the problem at an early stage. Careful examination of your eye before ICL surgery will help to identify any predisposition to retinal detachment, and the need for preventative laser treatment.
Alternatives to ICL implantation
The risks and benefits for ICL implantation must be set against those for alternative techniques, contact lens wear, and glasses. Contact lenses produce excellent visual correction for most patients, but maybe persistently uncomfortable or inconvenient, and are associated with an increased risk of sight-threatening infection. This risk is low provided hygiene is good and overnight wear is avoided. The annual risk of serious infection in contact lens wearers adhering to safe lens wear advice is approximately 1/3000.
Alternative surgical techniques for the correction of high myopia include refractive lens exchange (RLE)
RLE is exactly the same as cataract surgery. But, as the name suggests, the operation involves the removal of a clear natural lens rather than a cataract. An artificial lens is implanted to provide refractive correction. The main advantage of this technique is its familiarity to surgeons – cataract surgery is the commonest operation of any type performed today. Loss of the natural lens means loss of accommodation, or the ability to read without glasses. Accommodation and lens clarity both decline with age. So RLE is often preferred for patients over 50. For younger patients, ICL implantation is normally preferred, since this technique preserves natural accommodation and may be less likely than RLE to precipitate a retinal detachment.
Patients with a normal cornea who are ineligible for laser correction (LASIK) prior to ICL or TCL implantation can safely undergo LASIK treatment to correct any refractive error remaining after ICL implantation. For patients with very high starting levels of myopia (over -17.00D), a staged approach in which ICL implantation is followed up with LASIK one month later is commonly used. This 2 stage approach is often referred to as ‘bioptics’.
ICL implantation can be performed under either general or local anaesthetic. For people with no general health problems that could complicate anaesthesia, there is usually a choice. Modern general anaesthesia is safe and does not prevent same-day discharge. But a period of six hours without food and drink is normally required prior to surgery. This is not required for surgery under local anaesthetic. The operation usually lasts around 30 minutes.
After the operation
At the end of the procedure, the surgeon will remove the adhesive drapes, and place a plastic shield over the eye. This protective shield is normally worn for the journey home and during sleep for the first 7 days after surgery. Visual recovery after phakic IOL implantation is rapid. Patients can commonly see at the driving standard or better within 2 days of surgery. Mild gritty discomfort is normal, and eye may be relatively light-sensitive in the first few days after surgery. Beyond this, any post-operative discomfort should be minimal. Antibiotic and anti-inflammatory drops are normally instilled four times a day for the first 3-4 weeks after surgery.
Visual rehabilitation is rapid after ICL implantation, and any problems requiring revision treatment are normally apparent soon after surgery. Most patients are discharged after a 1-month postoperative check. We then normally ask that patients stay in touch with their local optometrist for an annual vision and eye health check. Although there is no evidence that ICL implantation increases the risk of glaucoma, high myopia is an independent risk factor. So the eye health check should normally include a glaucoma test.
>> Time off work
Although a return to most work activities is possible by the Monday following Friday evening surgery, you may wish to take time off, particularly in the week(s) between the first and second eye operations. Leaving one eye blurred (either wearing spectacles or leaving them off) may be uncomfortable, but does not strain or damage either the operated or the unoperated eye. Taking one spectacle lens out does not work (the unequal image sizes created feel very uncomfortable). Wearing a contact lens in the non-operated eye is the best solution where this is possible.
>> Preparation for the initial consultation
You should attend your initial consultation wearing an up-to-date spectacle prescription. Although we do not rely on this for choosing the ICL power to be implanted, this will facilitate your assessment. Read this information as carefully as possible, and prepare a list of questions to help cover any areas you are uncertain of at the initial consultation. Temporary changes in corneal shape are commonly associated with contact lens wear. If you are a contact lens wearer, you should not wear your contact lenses for 1 week (soft lenses) or 2 weeks (gas permeable hard lenses) before the preparatory visit. This will enable an accurate measurement of the corneal surface shape – important both in selecting your ICL and excluding abnormalities in corneal shape, which might influence the result of surgery.
>> Preparation for surgery
Do not wear any eye or facial make up on the day of surgery. Ordinary non-prescription sunglasses are useful whilst your eyes are mildly light sensitive in the early recovery period and are ideal for travelling home after surgery. Bring these with you. Finally, if you are having a general anaesthetic, remember you should have nothing to eat or drink for 6 hours before surgery (clear fluids can be taken up to 2 hours before surgery).
>> After surgery
Swimming is not recommended in the first week after surgery (because of a theoretical risk of infection), but other forms of exercise and flying are no problem. Try not to open your eyes under the shower for the first 3 days, and avoid eye bathing – just use the prescribed drops and clear any mucous build up from the eyelid margins using a cotton wool bud moistened in boiled water which has been left to cool to a comfortable temperature.