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KEY QUESTIONS

We're sure you will have many questions about laser eye surgery and whether it is the right option for you, however here we provide indepth details on the key questions we are asked most often.

For answers to other frequently asked questions about laser eye treatment please click here

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What are the main causes of blurred vision?

Our surgeon Mr Manoj Mathai, Ophthalmologist, CertLRS, MBBS, DO, MS, FRCS (Edinburgh) explains the causes of blurred vision in this video:

Normally the image of a distant object is focused onto the retina at the back of the eye by the cornea and the lens. The retina, in turn, converts this image into electrical impulses which the optic nerve transmits to the brain.

There are four main causes of blurred vision:

Myopia (short-sightedness)

This means that you can see clearly close up but you may find that objects in the distance are blurred. In this case there will be a minus sign (-) in the ‘sphere’ part of your prescription. You will probably need to wear your glasses all the time or for many everyday activities including driving, watching TV or sports.

Hyperopia (long-sightedness)

This means that close up objects (although sometimes objects in the distance too) may be out of focus. In this case there will be a plus sign (+) in the ‘sphere’ part of your prescription. You may need glasses for reading, using a computer, driving, watching TV or sports.

Astigmatism

This occurs when the curvature of your eye is not perfectly round. In this case there will be numbers recorded in the ‘cylinder’ and ‘axis’ parts of your prescription. Your vision could be blurred at all distances and, depending on the amount of astigmatism, you may need to wear your glasses all the time.

Presbyopia (the need for wearing reading / near vision glasses)

Presbyopia - the need for wearing reading glasses.
Presbyopia is a result of the eye’s ageing process and it affects everyone from their mid-40’s onwards.
This occurs when the natural lenses inside your eyes lose some of their flexibility so that it becomes difficult to focus on close-up objects. Presbyopia is a result of the eye’s ageing process and it affects everyone from their mid-40’s onwards. In this case there will be a figure in the ‘near’ or ‘intermediate’ part of your prescription and you will probably need glasses for reading.

Although laser treatment cannot correct presbyopia, allowances can be made for it by focusing one eye for distance vision and the other eye for near vision. This is known as monovision.

For many years the only way people could correct their vision was to wear glasses. However, wearers often complain of being able to see the frame, discomfort from daily wear and that their lenses steam up.

Over the last forty years contact lenses have become popular, although these also cause problems of their own for wearers. There is the daily routine of inserting, removing and cleaning the lenses, check-ups and collections. In addition, both spectacles and contact lenses can break or wear out, incurring costs for replacements.

More recently laser eye correction has been a major innovation in sight correction. Millions of people worldwide have now undergone laser eye correction and are enjoying the benefits.

If you would like to say goodbye to glasses or contact lenses, complete the form to book your appointment for laser eye surgery today.

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LASIK versus LASEK?

Lasers used in vision correction produce precise pulses of UV light energy which are delivered accurately onto the cornea. This energy weakens the bonds between atoms in the cornea so that microscopic amounts of tissue are removed in a process called cool ablation.

Since little or no heat is produced, no damage is done to the adjacent tissue allowing the computer guided laser to generate a new corneal profile as it sweeps back and forth across the eye.

Myopic eyes are given a flatter profile, hyperopic eyes are given a steeper profile and astigmatic eyes have their profile made more uniform.

Dr Stephen Doyle, Ophthalmologist, MBBS, BSc (Hons), MRCOphth explains the differences between LASIK and LASEK eye surgery in our video below:

Types of laser eye surgery:


LASIK - laser in situ keratomileusis.

LASIK is the most popular laser eye treatment.
LASIK is by far the most popular treatment due to the speed of visual recovery. In LASIK, an instrument called a microkeratome is used to form a flap on the surface of the eye which is thinner than a human hair. The laser treatment is applied to the exposed corneal tissue and then the flap is repositioned. The cornea has amazing bonding properties and almost immediately the flap adheres to the underlying tissue and begins to heal.

LASEK - laser epithelial keratomileusis
In LASEK the surface layer of cells, known as the epithelium, are displaced and then the laser treatment is applied. The displaced epithelial ‘flap’ is then put back in place and a plain contact lens put on the eye to help with the healing process. This contact lens stays in place until we remove it approximately three / four days later.

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Is laser eye surgery suitable for me?

To determine your suitability for laser eye surgery we have created a quick survey which you can take by clicking here.

If, after completing the survey, it indicates that you could be suitable please contact the clinic and you will be invited to visit us for a thorough assessment and consultation.

On arrival in reception you will be asked to complete a simple background questionnaire. The assessment part of the process is conducted by one of our experienced optometrists. Here we will check your prescription and take some very detailed measurements of the anatomy of your eyes. The optometrist will measure your pupil size, your corneal thickness and will also take some images of the front surface of your eyes. It is this information that will allow the ophthalmologist to decide if you are suitable.

Is laser eye surgery suitable for me?
Once you have had your assessment you will be brought back through to reception and will then go on to meet your ophthalmologist. This is the doctor who will ultimately treat you, should you be suitable and you are happy to proceed. The ophthalmologist will examine your eyes and review all the information gathered by the optometrist.

Please use this valuable time with your doctor to ask any questions you may have. There is no pressure at all for you to make a decision there and then. The purpose of the assessment and consultation is purely to determine your suitability so you can make an informed choice if you want to go ahead. We take no deposits from you and you will receive no follow up ‘sales’ calls.

You may be suitable for more than one type of treatment, which your ophthalmologist will discuss with you. 

Our optometrist Angela Critchley explains in this video what conditions may prevent you from having laser eye surgery:

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Which type of laser eye surgery is best for me?

The table below provides a direct comparison between LASIK and LASEK laser eye treatments, however your surgeon will discuss these with you so you can decide which course of treatment is best for you.

 
LASIK
LASEK
Return to useful vision
LASIK
1-2 days
LASEK
4-7 days
Post-op discomfort
LASIK
1-8 hours (if any)
LASEK
2-3 days
Time of work
LASIK
1-2 days
LASEK
3-4 days
Myopia (short-sightedness)
LASIK
Up to -10.00D
LASEK
Up to -10.00D
Hyperopia (long-sightedness)
LASIK
Up to +6.00D
LASEK
Up to +6.00D
Anaesthetic
LASIK
Eye drops
LASEK
Eye drops
Treatment time
LASIK
10 mins per eye
LASEK
10 mins per eye
Both eyes treated together
LASIK
Yes
LASEK
Maybe
Steroid eye drops
LASIK
1 week
LASEK
Up to 6 weeks

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Can laser eye surgery correct the need for wearing reading glasses?

If you are between 40 - 45 years of age (or older) and wear glasses for distance, you may have started to need help for reading / near vision too. This is usually addressed by changing your single vision spectacle lenses to bifocal lenses or varifocal lenses.

If you don’t or have never worn distance glasses, by the time you reach 40 -45 years of age (or older) you will still develop the need for reading / near vision glasses as this is due to the natural ageing of your eyes and this condition is referred to as presbyopia.

For patients in this age category who are considering laser eye treatment, and who want independence from both distance & reading glasses, the only viable option is monovision.

The guide and video below will explain monovision in more detail.

Monovision is the situation where the focus of one eye is set for distance and the focus of the other eye for near. This is a strategy for reducing dependence on reading spectacles whilst not overly compromising distance vision.

In the youthful eye there is a natural ability to adjust focus from distance to near. This is gradually lost with advancing years. In children and young adults the natural lens within the eye is very pliable and a muscle acts upon it to change its shape. As the lens changes shape so the focus of the eye is altered. This is why young children and young adults, who can see clearly in the far distance, can also see clearly just inches from their nose.

Unfortunately the lens becomes stiffer with ageing and, although the muscle still works, it is less able to modify the lens shape. By mid forties the focusing reserve of the eye has diminished so that when tired or in poor light, clear near vision cannot be achieved or sustained and near vision spectacles become necessary.

This declining focus adjustment of the eye is called “loss of accommodation”, and the age related inability to see at near is called “presbyopia”. Science has not yet come up with a way of truly restoring the youthful focus adjustment to the eye.

Monovision is a way of overcoming this problem. It is a compromise. A deliberate difference is created between the two eyes. One eye has clear distance vision whilst the other eye has clear near vision. Some individuals adapt to this and some do not. Monovision “works” when the individual is unaware of the difference between the eyes and just attends to the image that is in best focus.

As gaze changes from distance to near the brain must flip from attending to the image from one eye to that of the other. The person lives with both eyes open and sees with whichever eye has clearer vision. Of course the eye that is a little out of focus is still contributing to vision. How long it takes to get used to this new way of seeing varies from one person to another. Some people take to it almost immediately but others never seem to be able to overcome the awareness that one eye is blurred.

Monovision can deliver social independence from reading spectacles. By this I mean the ability to see mobile phones, your wristwatch, shop prices and restaurant menus. It is rarely as good as near vision with spectacles. This is because with reading glasses both eyes are being used to read and with the full correction. With monovision only one eye is in focus for near and usually the correction is toned down a bit to avoid creating too great a difference between the eyes.

Monovision may not give total independence from spectacles. There may be some situations where it is preferable to have the eyes in synchronous focus. One example is driving at night. With monovision one eye will have blurred distance vision. Oncoming headlights will form starburst images in that eye which may be distracting. The solution is to use spectacles that refocus that eye for distance. When reading challengingly small print for extended periods spectacles may provide more acceptable near vision.

The important thing to understand when deciding if monovision is for you, is to accept that you may not have perfect distance vision AND perfect near vision. It is a compromise. Patients who adapt best are the ones who have a realistic expectation of the outcome. For most, monovision gives them independence from distance and near glasses for the vast majority of the time, however they accept that visual aids may be required for challenging distance and near tasks.

As you continue to get older, your near vision will continue to diminish so you need to think of monovision as turning the hands back on a clock…we can re-set you, but we can’t stop the clock ticking…. However, the benefit you achieve from monovision will always be in “the bank” so even if you do require additional assistance for near vision in the years to come, the benefit of your monovision will still provide a degree of independence.

If laser treatment is being considered, it is wise to discuss this with your ophthalmologist at your consultation and to have a contact lens trial of monovision first to be sure that you can adapt to it. We can arrange this for you with Martin, our contact lens practitioner.

Monovision can be achieved with using the LASIK and the LASEK methods of refractive surgery.

I hope this guide has helped explain what monovision is and what it can achieve. If you would like any further information, please do not hesitate to contact one of the team here and we will be happy to discuss this in more detail.

 

Footnotes:

  • Monovision rarely works well in spectacles because of the unequal magnification caused by different lenses when placed away from the eye.
  • For monovision to be a success both eyes must have about equal best vision. If one eye has significantly poorer best vision (e.g. is a “lazy eye”) the brain will struggle to hand over visual attention from one eye to the other. It will always want to see with the better eye.
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Is laser eye surgery safe?

The video below from our experienced laser eye surgeon Dr Stephen Doyle, Ophthalmologist, MBBS, BSc (Hons), MRCOphth explains why laser eye surgery is a safe procedure: