Clinical and Experimental Ophthalmology

2005;

33

: 341–342

Blackwell Science, LtdOxford, UKCEOClinical and Experimental Ophthalmology1442-64042005 The Royal Australian and New Zealand College of OphthalmologistsAugust 2005334341342Editorial

EditorialEditorial

Editorial

The desperate last gasps of rigid contact lenses

can be used to reduce myopia by about 2.00 D, no matterwhat approach to fitting is adopted.

4,5

However, the magni-tude of the effect is unpredictable, and vision regresses at anuncertain rate back to the original state of myopia during thewaking hours.

4,6

Orthokeratology enthusiasts dismiss suchevidence as being erroneous because they claim that all pub-lished research has been conducted using outdated lensdesigns. This is the trick of the orthokeratologist. By comingup with new, slightly revised and purportedly superiordesigns almost every month, they claim that all previousresearch is irrelevant. The simple reality, however – as suc-cinctly put by Kwok and Pierscionek in this issue of theJournal – is that earlier findings of the limited efficacy oforthokeratology

7

are simply being rediscovered today.The question of the safety of orthokeratology is vigor-

ously debated in this issue of the Journal. While not wantingto act as a referee with respect to the various arguments, Iwould comment that I am alarmed at the growing number ofreports of severe keratitis in patients undergoing orthokera-tology. Swarbrick argues that reports of keratitis can beignored because most cases occurred in East Asia. I rejectthis. If lack of hygiene and poor patient education in theseregions is the reason for higher rates of keratitis amongpatients undergoing orthokeratology, then we also should beobserving a higher incidence of keratitis with all forms ofcontact lens wear in East Asia. To the contrary – the rates ofcontact lens-associated keratitis in Hong Kong

8

appear to be

lower

than in Western populations.

9

My attitude to orthokeratology can be summed up in twowords: ‘Why bother?’. The great irony of orthokeratology isthat it is not a procedure that will allow one to avoid havingto wear contact lenses. Lenses still have to be worn over-night. Whenever I point this out, I am told that orthokera-tology is for patients who do not want to have to rely onwearing contact lenses. Presumably this means that ortho-keratology can be used as some form of psychological crutchfor those mentally fragile few who take this view. Modernsoft contact lenses are instantly comfortable and providesharp vision for patients with all forms of ametropia. Ortho-keratology lenses are expensive, difficult to fit, uncomfort-able when inserted, provide variable vision and probablyincrease the risk of developing severe keratitis . . . so whybother?

Now I shall turn my attention to the question of the useof rigid lenses for myopia control. It is surprising that sucha large amount of funding has been invested for the runningof clinical trials to investigate a procedure for which there isno raison d’être. I am unaware of any convincing evidence

The ‘Clinical Controversy’ article in this issue of the Journalhighlights a much broader issue facing modern contact lenspractice, about which many practitioners and researchers arein denial.

1

Simply put: we are witnessing the demise of therigid contact lens. I have been tracking international contactlens prescribing trends for some years and the evidence isclear. As a proportion of all lens types, rigid lenses are beingprescribed less and less, and we have now reached the pointwhereby, internationally, rigid lenses constitute only 11% ofall new lens fits (although slightly higher in Australia andNew Zealand at 16%).

2

There are many reasons for the decline in rigid lens fit-ting. I have discussed these at length elsewhere

3

and will notrepeat them here in detail. In essence, I believe that thedecline in rigid lens prescribing is due to the following fac-tors: optometry students and ophthalmology residents arenot being exposed to rigid lens fitting as part of their prac-tical training because virtually all patients are demanding tobe fitted with soft lenses; soft lenses are more comfortableand require no adaptation period; soft lenses usually can besupplied to the patient immediately from an in-office inven-tory; and soft lenses can now satisfy virtually all opticalrequirements (such as toric lenses for the correction of astig-matism). Of course, rigid lenses will always be required forcases of corneal irregularity such as keratoconus or post-traumatic/post-surgical corneal distortion; however, I esti-mate that such cases would overall not exceed 0.5% of lenswearers.

3

So why all this interest in ‘alternative therapies’ such asorthokeratology and the fitting of rigid lenses to arrest theprogression of myopia? The reasons are complex and varied.A key driving force behind much of this activity is a desper-ate attempt by commercial interests to shore up a failingindustry. The logic is that if the public and practitioners areshying away from rigid lenses for general cosmetic use, a‘specialist’ niche market can be created based upon lavishclaims of temporarily or permanently curing myopia.Another driving force is the clinical interest of practitionersand the academic curiosity of researchers. Unfortunately,many orthokeratology practitioners seem to be motivated bycommercial profit. Orthokeratology is a very profitable pro-cedure, requiring numerous visits and the fitting of manyexpensive lenses over a short period of time. I suspect thatmany academics have an interest in orthokeratology: notfrom a clinical perspective, but from a genuine desire tounderstand corneal physiology and rheology.

Two key factors relating to orthokeratology are its effi-cacy and safety. It is clear that overnight orthokeratology

342 Editorial

to support the notion that rigid contact lenses (and not softlenses) can arrest the progression of myopia, apart from thevague principle that rigid lenses, because they are typicallysmaller than the cornea, do not correct vision in the farperiphery of the retina, and this degraded peripheral visionsomehow interferes with normal eye growth. Irrespective ofthe merits of that argument, two recent, well-controlled clin-ical trials have failed to demonstrate that rigid lenses arecapable of controlling myopia.

10,11

Walline

et al

. explainedthat the small effect in reducing myopic progression in theirstudy was probably due to reversible physical moulding ofthe cornea, and concluded that rigid lenses should not befitted as a strategy for myopia control.

11

In 2000 I predicted that rigid contact lenses would bevirtually obsolete by the year 2010.

12

We are now half waytowards that prediction, and I have no reason to change myopinion. The concepts of orthokeratology and myopia con-trol using rigid lenses are untenable, and in my view repre-sent the desperate last gasps of rigid contact lenses.

S

TATEMENT

OF

COMMERCIAL

INTEREST

My research group, Eurolens Research, receives united spon-sorship from the following companies: Bausch & Lomb,Advanced Medical Optics (UK), Alcon Laboratories (UK),CIBA Vision (UK), CooperVision, Johnson & Johnson VisionCare, Menicon Co., Sauflon Pharmaceuticals and ClearlabUK. Ongoing contractual research is also conducted withmost of these companies.

Nathan Efron PhD DSc FAAO

Professor of Clinical Optometry, Department of Optometry andNeuroscience, The University of Manchester, Manchester, UK

R

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International contactlens prescribing in 2004.

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