Lowes & Partners Optometrists, Whangarei, Kerikeri & Kaikohe New Zealand

A GUIDE TO ORTHOKERATOLOGY

What is Orthokeratology?

Orthokeratology, or Ortho-K, is a specialist field of contact lens fitting which:

• involves the use of specially designed rigid gas-permeable (RGP) contact
lenses to alter the shape of the cornea
• reduces or corrects myopia (short-sight)
• reduces or corrects hyperopia (long-sight)
• reduces or corrects astigmatism
• has been practiced for many years, but up until the turn of this century the results had been disappointing, with variable and often minor degrees of reduction in myopia
• it was first practiced by the Chinese 1000 years ago when they slept
with small sandbags placed over their eyes

However since the early 2000’s new technology became available.

• to produce topographical maps of the cornea with incredible accuracy
• to design lenses utilising advanced software
• to manufacture reverse geometry lenses using computerised lathing to achieve a controlled and precise reduction in the cornea’s profile
• to develop new lens materials that enable safe overnight lens wear
• to ensure that the technique of Ortho-K is now
• safe
• viable
• reliable
• reversible
• an noninvasive alternative to refractive surgery

The cornea, being semi-elastic, returns to its original shape if the lens wear is stopped. The lenses are worn nightly during sleep with most people only requiring to wear lenses every second night to achieve stable vision.

Why Have Ortho-K Done?

The main purpose of Ortho-K is to be free of both contact lenses and spectacles for the majority of, or more typically, all waking hours. The freedom from any artificial aids appeals to myopic spectacle and contact lens wearers and is ideal for sportspeople, those who work in dusty environments or people who find spectacles and conventional contact lenses inconvenient. Most clients wear the lenses overnight and remove them on awakening, although some clients wear them during the day for a short booster period.

Possibly one of the ideal situations for using Ortho-K is for teenagers with early myopia. Not only does it have all the advantages already given above, but also the procedure can help reduce the progression of the myopia. There is evidence that ortho-k reduces the progression of myopia by 50% by minimising peripheral defocus at the retina, something no other contact lens or spectacle lens can do. Peripheral defocus caused by conventional lenses is thought to play a major part in the continuing development of myopia.

How does Ortho-K Work?

The special, individually designed, contact lens gently moulds the cornea to the required shape during sleep by creating hydraulic pressure on the corneal tissue which, like all our bodily tissues, is semi-elastic.

It is precisely this inherent semi-elasticity that makes the procedure safe and reversible because if wear is ceased the cornea reverts to its original shape. This is important for in the case of myopia in later years there can be an advantage in being shortsighted so that one can read without the use of visual aids. This facility is lost in laser surgery which causes irreversible change to the shape of the cornea.

Is Everyone Suitable for Ortho-K?

NO: The procedure works best up to a maximum of 5.00 dioptres of myopia, 3 dioptres of hyperopia and 2.50 dioptres of astigmatism. Errors above this may be reduced but total correction is not usually possible. In addition there are several unknown factors for each individual: the complexity of the corneal shape and the response of the cornea itself. Thus the speed of corneal moulding from one individual to the next will vary. Whilst the success rate is very high, total success cannot be guaranteed due to these factors.

What Does The Initial Visit Involve?

The initial assessment appointment includes a full eye examination and computerised corneal topographical scanning. This gives the practitioner a chance to assess both the general condition and health of the eyes and also to determine the likely effect of the procedure in that individual. Ortho-K contact lenses, made from highly oxygen permeable rigid material, are then fitted using the results of the corneal scan to gently reshape the cornea towards less curvature and a more spherical shape. These will be worn for an initial trial and the response evaluated. This will typically take place overnight with a review the next morning. The effect will be a reduction of the myopia, hyperopia or astigmatism with improvement in the unaided eyesight. The corneal health will be carefully evaluated to ensure it is not compromised. Only when the client demonstrates an excellent response to the orthokeratology trial will the treatment programme commence.

What Does The Treatment Involve?

Once a client has shown the appropriate response to a trial, they will start to wear lenses on a regular basis, typically overnight. For the first two to four weeks the vision may not be sufficiently good for all day-to-day activities. In theses circumstances daily disposable soft lenses will be worn. After the first month, excellent vision and comfort are normally maintained whilst wearing Ortho-K lenses. Occasionally more than one set of lenses may be required to effect the desired change.

As most of the visual changes occur rapidly in the first few weeks and typically in the first night, fairly frequent examinations and possible lens changes need to take place then. Stabilisation procedures then follow at a slower pace over the next few weeks. The programme length varies between 1 and 2 months until stabilisation occurs and depends upon the degree of refractive error. The fees for orthokeratology treatment include all visits in the first year.

The final wearing time depends on many variables, but the treatment aim is good unaided vision all or most waking hours, with lenses being worn overnight or part of each day only. Some clients will be able to wear their lenses every second night.

Does Ortho K Have Any Advantages Over Laser Surgery (Lasik)?

Yes

• No ethical surgeon will treat a patient until they are at least 18, or more usually 21 years old. Therefore there is an age limitation with laser surgery.
• It does not cause the permanent hazy vision experienced by some patients following laser surgery.
• Changes in prescription over time can be dealt with without further surgery.
• The procedure is REVERSIBLE (Lasik is not).
• There is very significant understanding of the effects of contact lens wear on the cornea, because of the many years of lens use. Lasik’s effects are not totally understood.
• There is no post-operative pain or recovery period.
• Ortho-K is significantly cheaper and does not preclude surgery in the future.

What Are The Advantages of Ortho-K?

• Good vision without spectacles or contact lenses for most of the day.
• It is not a surgical procedure.
• It is reversible.
• It is modifiable.
• It does not hurt.
• It may slow down the increase in myopia in children.
• Using well established contact lens fitting techniques means that there are very few risks.

What Are The Advantages of Ortho-K?

• You must be prepared to allow for 4 – 6 visits over 3 – 6 months.
• Continued lens wear is essential or the cornea will revert to its original shape.
• The degree of success is high but cannot always be guaranteed.
• The speed of reduction in the myopia varies from one person to the next.
• You must follow instructions implicitly for the best results.

Risks of the treatment

Contact lenses have been used for orthokeratology since the early 1960’s and controlled scientific studies have not documented any harmful health risks to the eyes. However, with all contact lenses, whether they are worn overnight or during the day, there are potential risks of transient irritation to the eyes whether caused by allergy, reduction in oxygen access or mechanical stimulation. These effects will ease on lens removal and are not sight threatening. The only sight threatening potential complication is corneal infection and ulceration which occurs at a very low rate in rigid contact lens wearers of approximately 1 – 5 cases per 10,000 wearers. In the rare situation where a corneal infection does occur then providing prompt medical attention takes place any loss of vision is rare. Day-time wear and overnight wear therapies have received FDA approval in the United States.

Cost

The procedure is time consuming and may involve several lens changes. For this reason the initial costs are greater than conventional contact lens correction but less than refractive surgery. Once the treatment is complete, the on-going costs are significantly less than the latest options in soft contact lens wear, since the lens life may be up to four years. The current charges are $70.00 for the initial consultation and trial and $1530.00 in staged payments for the rest of the treatment making $1600.00 in all which includes the cost of one set of Ortho-K contact lenses.

Fee ScheduleInitial Consultation

Includes comprehensive internal and external ophthalmic examination to evaluate refractive status, state of ocular health, suitability for procedure, advice on alternatives, corneal topography measurement and determination of diagnostic parameters. Cost: $70.00 payable after examination.

Diagnostic lens trial

An evaluation of the refractive changes and corneal topographic changes that occur following either an overnight wearing period or wear over 4 – 5 hours during the day. If treatment is successful prescription lenses will be ordered.

Cost: $60.00. This fee is included in the treatment programme fees and will only be charged as a separate item if the treatment programme is not implemented.

Treatment programme

Several visits will be scheduled during the six month programme. These will be individually set, but will occur approximately one week after lens issue and then one month, three months and six months after lens issue. There are no additional fees if extra appointments are necessary.

Cost: $710.00, half to be paid at one month visit remainder at three month visit.

Materials

A pair of hyper oxygen permeable Orthokeratology lenses will be charged for at the start of the treatment programme. If refitting for clinical reasons is required during the first six months no further charges for materials will be made.

Cost: $820.00 per pair. Payable at time of supply.

Total cost

$1600.00

Further costs

An annual review will be required during which lens condition and performance will be evaluated, corneal topography measured and full review of internal and external ocular health. Cost: $100.00 payable at time of appointment.

It is advisable at some point to order a spare pair of lenses in case of loss damage or for contact lenses being returned to the laboratory for polishing. Cost: $640.00 per pair if ordered within first year.

Refund policy

Should the treatment be discontinued by either the patient or the practitioner for any reason on or before the one month visit then the patient will pay only the initial examination while the prescription lenses must be returned to the practice. Should discontinuation occur on or before the three month visit then the patient will be asked to pay half of the treatment programme costs ($355.00) providing the lenses are returned to the practice.

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