Gartry's Principles!

Results borne from Experience

The following principles, or ‘rules of laser eye surgery’, are based on over 25 years’ experience and result from listening to patients before and after their treatments on a one to one basis – which David Gartry considers to be very important indeed. There is no substitute for discussing the treatments in detail before, during, and after the surgery with the treating surgeon. These principles or ‘rules’ help in the management of patients’ expectations – especially in relation to close reading vision for those over 40!


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David Gartry examining patient results data at The Wimpole Street Eye Clinic, London

David Gartry's Principles Part 1

“Gartry's Principle No. 1” (the 90% Rule)

“Almost all patients have almost all of their myopia eliminated with a single treatment!”

From the above results it is true to say that almost all patients have at least 90% of their prescription eliminated.  This applies even to the high prescriptions.  For example,  patients with -10 dioptres of myopia would be typically left with -1 dioptre or less.  On average, only 3-4% of patients have a retreatment procedure within the first six months to “fine tune” the result.  As can be appreciated from the above results, these patients tend to be those who had very high prescriptions initially.

David Gartry's Principles Part 2

“Gartry's Principle No. 2”

“Short-sighted (myopic) patients prefer to be left with a a small amount of myopia – if anything.”

Given that it is impossible to promise perfection in every case, and since it is rare for patients to have absolutely zero prescription (even Royal Air Force pilots have tiny prescriptions for which they do not require spectacles of course), it is always better to remain slightly short-sighted if you have been myopic (short-sighted) before – and slightly long-sighted (hypermetropic) if you have been long-sighted in the past.  Myopic patients tend to adapt well to small amounts of residual myopia – say, -0.50 dioptres – while long-sighted (+) patients prefer +0.50 dioptres, if not absolutely zero prescription.

“Gartry's Principle No. 3”

(More of an observation really!)

“Patients over 40 ALWAYS under-estimate their natural need for reading spectacles.”

Patients who are moderately short-sighted prior to the surgery, and could therefore read well unaided without any spectacles (for example when reading in bed), would often find it difficult to adapt to losing this ability.  Simply stated, if patients have an excellent result which allows them to see very well indeed for long distance (normal vision – emmetropia) then beyond aged 40 they will certainly find it more difficult to read and from mid-40s onwards would often use simple reading spectacles.  In David Gartry’s experience this principle is one of the most difficult to convey to patients prior to their surgery.  However the advantage of being able to see well without spectacles – often for the first time in their lives – usually more than outweighs the disadvantage of reduced near vision  for patients over 40.

David Gartry's Principles Part 2

“Gartry's Principle No. 4”

“Short-sighted (myopic) patients rarely realise that the only reason they can read unaided without spectacles at close distances is BECAUSE they are short-sighted.”

They won’t be able to do this once their myopia (short-sight) has been corrected. These, and many other aspects (age, occupation, sports and hobbies and monovision or blended outcomes) are carefully taken into account when deciding on the programming of the laser.  The desired outcome is carefully planned during discussions with each patient. Very rarely is the simple spectacle prescription programmed into the laser without modifications.