Refractive Errors

What is the Crystalline Lens?

The Crystalline Lens is a transparent, biconvex structure in the eye that, along with the Cornea (the clear ‘window’ at the front of the eye), helps to focus light on the retina. In young people, the lens is able to accommodate; it can change the focal distance of the eye by changing its shape, so that objects at different distances can be kept in focus.

What is Refractive Errors?

In individuals with a refractive error, the optics of the eye (Cornea and Lens) cannot focus light from distant objects on the retina.

Common refractive errors include:

  • Myopia: When the optics of the eye is too powerful for the length of the eyeball, one has Myopia or Near-sightedness.
  • Hyperopia: When the optics of the eye is not powerful enough for the length of the eyeball, one has Hyperopia or Far-sightedness.
  • Astigmatism: When the optics of the eye is too powerful or too weak across one meridian. A person with Astigmatism sees lines of a particular orientation less clearly.
  • Presbyopia: When the flexibility of the Lens declines due to age, leading to difficulty in near vision.

What is Refractive Lens Exchange Surgery?

Refractive Lens Exchange (RLE) Surgery is an operation to remove the lens and replace it with a clear artificial lens implant. The power of the lens implant can be customised to overcome the Refractive Errors in each person and achieve clear focused vision at the desired distance or distances to best suit your lifestyle.

Am I suitable for Refractive Lens Exchange Surgery?

Refractive Lens Exchange surgery can be considered from the age of 45-55 onwards, when the irreversible decline in the ability of the Crystalline Lens in your eye to accommodate (the ability to focus on objects at various distances) sets in.

Refractive Lens Exchange surgery can also be considered if you already have significant refractive errors such as Myopia, Hyperopia and Astigmatism. In these cases, Refractive Lens Exchanging is likely to be ‘life-changing’, from being highly dependent on glasses or contact lens, to a virtually glasses-free or contact lens-free lifestyle.

What are the choices of Lens Implants?

The choice of lens implant is very much dependent on your lifestyle. In the Medical Eye Clinic, we take great care to understand your lifestyle requirements and to do our best to match the choice of lens implants to your lifestyle. We ask that you kindly complete a questionnaire when you come to see us to consider Refractive Lens Surgery:

After a comprehensive assessment of your eyes and careful discussion of your lifestyle requirements, the following are the most common Lens Implant options:

Multifocal Lens Implants in both eyes.

This is the option that is most likely to help facilitate a ‘Glasses Independent’ lifestyle.

As the only Zeiss Reference Centre in the South West, The Medical Eye Clinic uses the technologically advanced Zeiss AT LISA TRI Lens to achieve simultaneous Distance, Intermediate and Near focus in both eyes.

Blended Monovision Implants

With this option, the ‘dominant’ eye is implanted with a Monovision Lens to achieve Distance vision, and the ‘non-dominant’ fellow eye is implanted with a Monovision Lens to achieve Near vision.

This option is most suitable if you are already used to a blended Monovision arrangement with your contact lens or glasses prescriptions.

At the Medical Eye Clinic, we also use the Zeiss CT Lucia 611 Lens, a technologically advanced Mono-focal lens that can be introduced in to the eye through a small 2.4mm incision, and whose superior optical properties give unsurpassed clear vision at the desired distance.

Distance Monovision Implants in both eyes

This option is suitable for you if you have a predominantly ‘outdoor’ lifestyle and choose to have clear distance vision. With Distance Monovision Implants in both eyes, you are likely to be able to enjoy spectacle-free clear distance vision, and need to use Readers for reading and near distance work.

Again, the Zeiss CT Lucia 611 will be used to achieve this Refractive Lens Exchange option.

Toric Lens Implant

If you have significant Astigmatism (more than 1.0 -1.50 Dioptre), a precisely implanted and aligned Zeiss AT TORBI Toric Lens can be used to achieve clear focus in the astigmatic meridian.

The Medical Eye Clinic is the first Eye Clinic in the U.K. to adopt the Zeiss Callisto image-guidance Toric alignment system, to achieve precise alignment of Toric lens Implants to the Astigmatic Meridian, and remains the only Private facility in the Exeter area to have this.

Multifocal Toric Lens Implants are also available if you have significant astigmatism and wishes to achieve Multifocal vision in both eyes.

What are the alternatives to Refractive Lens Exchange Surgery?

The alternatives to Refractive Lens Exchange Surgery are:

  • Continue to wear glasses
  • Continue to wear contact lenses
  • Refractive surgery on the Cornea may be appropriate for people with certain type of refractive error.

What are the potential complications?

Modern RLE surgery is one of the safest surgeries that is frequently performed today, and it consistently achieves good outcomes. However, all surgical procedures can have potential complications. It is possible for RLE surgery to leave your vision worse than it is now.

One person in every 1000 will go blind in the operated eye as a direct result of the surgery. One in 10,000 will lose the eye. There is virtually no risk to the unoperated eye.

The most common complications are:

  • Complications During the operation: Posterior capsule rupture with or without vitreous loss 1 in 100; Dropped nucleus 1 in 500; Suprachoroidal haemorrhage 1 in 1000; Bruising of the eye and eyelids.
  • Complications After the Operation: Corneal decompensation; Detached retina 1:1000; Endophthalmitis (severe intraocular infection) 1:1000; Dislocation of the implant 1:1000; Post-operative raised intraocular pressure; Posterior capsule opacification 20-30% over 5 years; Cystoid macular oedema 2%; Refractive surprise 1% and Allergic reaction to post-operative eye drops.

One of the most feared complications in Refractive Lens Exchange Surgery is an infection developing in the eye after surgery (Endophthalmitis). Within The Medical Eye Clinic operating theatre, we have the most advanced ‘Clean Air’ filtration system, to provide the very best sterile environment for your surgery.

Preparing for Refractive Lens Exchange surgery

During your consultation and the pre-operative assessment appointment with your eye surgeon, your surgeon will:

  • Perform a thorough examination of your eyes. This includes measurement of your vision, biometry to take measurements of the size and shape of your eyes, detailed examination of the health of the front and back of your eye (Macula).
  • Discuss with you the risks and benefits of surgery.
  • Discuss the different Refractive Lens Exchange Surgery lens options, that would be best suited for your eye and your lifestyle, with the help of your completed questionnaire.
  • Your surgeon will discuss with you what will happen before, during and after your procedure, and any pain you may experience. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will enable you to give informed consent to proceed with the procedure.
  • You will be given a consent form to take home and read.
  • You will be asked to give your consent by signing a consent form on the day of surgery.

What happens during Refractive Lens Exchange surgery?

Refractive Lens Exchange surgery is carried out as a day case. This means you have the procedure and go home on the same day.

The operation usually takes approximately 30 minutes.

You will be given eye drops to widen your pupil and relax the muscles in your eye. This will make it easier for your surgeon to examine your eye and remove the lens.
The operation is carried out under Local Anaesthetic with both eye drops and a sub-Tenon anaesthetic injection given by your Consultant Anaesthetist. This completely blocks pain from the area around your eye whilst you are awake during the procedure. Additional light sedation is also available if you and your Consultant Anaesthetist think this will help make the surgery more comfortable.

Once the anaesthetic has taken effect, your surgeon will place a clean drape over your face. The drape will form a small tent over your face so you can still breathe and speak easily.
A small speculum is used to keep your eye open during surgery. Your surgeon will make tiny cuts on the surface of your eye to carry out the surgery. Although you may see some lights and movements during surgery, you will not be able to see the instruments being used or feel any pain.

Your surgeon will use a special instrument to remove the lens and you may hear a soft buzzing sound when it is being used. The lens will be removed from your eye leaving behind the capsule it sits within. The new artificial lens is then put in, where it will stay permanently.
Your surgeon will usually leave your eye to heal naturally without stitches.

What can I expect afterwards?

After a local anaesthetic, it may take several hours before the feeling returns to your treated eye. Your eye is covered with a protective plastic shield, which you will need to wear overnight.

You may need pain relief to help with any discomfort as the anaesthetic wears off. You will be given combined steroid and antibiotic eye drops to use at home to help control inflammation and prevent an infection in your eye.

You will usually be able to go home when you feel ready. However, you will need to arrange for someone to drive you home. Try to have a friend or relative stay with you for the first 24 hours.

Recovering from Refractive Lens Exchange surgery

It is important to complete the whole course of the prescribed combined steroid and antibiotic eye drop medication.

If you need pain relief, you can take over-the-counter painkillers such as Paracetamol or Ibuprofen. This is usually only needed for the first 24-48 hours after surgery.

Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice.

You should start to get feeling back in your eye after a few hours. Your vision should start to improve within a few days, however it may take a few weeks to heal completely.

There are some important instructions to follow for the first 10 days after cataract surgery. The main ones are listed below.

  • Try to avoid touching or rubbing your eye. If you are a restless sleeper you can wear an eye patch at night to protect your eye.
  • Try to keep soap and shampoo out of your eyes.
  • Try to avoid heavy lifting or strenuous exercise for the first few weeks after the operation, as this can increase the pressure in your eye and could put strain on your healing scar.
  • Try to avoid wearing eye make-up, drive or go swimming until your surgeon tells you it is safe to do so.
  • If you go outdoors when it is windy, please protect your eye from grit and dust.

It is not unusual to experience some of the following symptoms in the initial days after cataract surgery:

  • An itchy or mild sticky discharge from your eye
  • Mild pain, discomfort and bruising of your eyelid or eye
  • Sensitivity to bright light
  • Mild blurring of vision that usually returns to normal

However, if you experience any of the following symptoms, please contact your surgeon urgently:

  • Severe pain
  • Loss of vision
  • Redness in your eye that continues to worsen

Follow up visits after Refractive Lens Exchange

It usually takes about two to six weeks to make a full recovery from surgery, but this does vary between individuals, so it is important to follow your surgeon’s advice.
Your surgeon will usually arrange to see you for a check-up appointment 2-4 weeks’ after your surgery. After satisfactory recovery of the first eye, plans will be made to proceed with the second eye Refractive Lens Surgery.

Written by - Roland Ling BM, Bch (Oxford); FRCOphth