Orthokeratology (Ortho-K)
Orthokeratology (ortho-k) in Hamilton: overnight contact lenses for clear daytime vision
Orthokeratology — ortho-k, sometimes called overnight contact lenses or night lenses — is the use of a specially shaped rigid contact lens worn overnight. The lens gently reshapes the front surface of the cornea while you sleep. You take the lenses out in the morning and, for most of the day, see clearly without glasses or daytime contact lenses. It is non-surgical, and it is reversible: stop wearing the lenses and the cornea returns to its original shape over days to weeks. At Rose Optometry in Frankton, Hamilton, we fit orthokeratology using Shift lenses and related designs, and we have been fitting rigid specialty lenses here since long before ortho-k became widely available in New Zealand. Partner optometrist Jagrut Lallu is a Fellow of the International Academy of Orthokeratology and Myopia Control.
Start with a free Shift/Ortho-K Chat: book a 15-minute Ortho-K Free Chat with one of the optometrists — no cost, and the quickest way to find out whether overnight lenses suit your eyes and your lifestyle. Ready to be fitted? New Ortho-K / Shift fit (30 minutes). Already wearing them and due for review? Orthokeratology / Shift full exam (30 minutes). Prefer to talk it through? Call 07 847 3195.
Who orthokeratology suits
Ortho-k works best for short-sightedness (myopia), with or without a moderate amount of astigmatism. It suits:
- Children and teenagers with progressing myopia. This is now the most common reason we fit it. Ortho-k both corrects vision during the day and is one of the evidence-based options for slowing the progression of myopia in children. It slows progression; it does not stop or reverse it, and no treatment can promise a particular result for an individual child.
- People in dusty, windy or sweaty environments — farming, construction, workshop work, swimming and contact sport — where daytime lenses are awkward and glasses get in the way.
- Office workers whose eyes dry out in air conditioning and who find soft lenses uncomfortable by late afternoon.
- People who like the idea of laser surgery but do not want surgery, or who are not yet suitable for it because their prescription is still changing.
It is less suitable for high prescriptions beyond the fitting range, for significant irregular astigmatism (where a different specialty lens is usually better), for people with active dry eye or lid disease until that is treated, and for anyone who cannot commit to careful nightly lens hygiene.
How ortho-k fitting works at Rose Optometry
- Assessment and corneal mapping. We measure your prescription and map the shape of your cornea with topography, the same technology we use for keratoconus. The map, not a guess, determines the lens design.
- Trial lenses. We fit trial lenses in the practice, check the fit on the eye, and order your lenses.
- First nights. You wear the lenses overnight and come in the next morning, ideally with the lenses still in, so we can see exactly how they have been sitting.
- Review and refinement. Vision usually improves over the first few nights and settles within one to two weeks. Small design changes at this stage make a large difference; this is where careful fitting earns its keep.
- Ongoing care. Reviews at agreed intervals to check corneal health, vision and — for children — axial length, so we can see whether myopia is actually being slowed.
Safety, honestly — and why we are strict about water
Ortho-k is a well-established treatment with decades of use, but it is still contact lens wear, and any overnight lens carries a small risk of corneal infection. Published estimates put the risk of microbial keratitis in overnight ortho-k in a similar range to other overnight lens wear — low, but not zero. That risk is reduced by good hygiene, correct solutions, replacing lenses and cases on schedule, and not wearing lenses when your eyes are red, sore or watering. We will teach you the routine properly, and we would rather you called us and skipped a night than pushed through.
The infection we work hardest to prevent is Acanthamoeba keratitis. Acanthamoeba is a microorganism that lives in tap water, tank water, bore water, swimming pools, spa pools, rivers and lakes. It is uncommon, but when it reaches the cornea under a contact lens it is painful, slow to treat and can permanently damage sight. Our partner optometrist Jagrut Lallu is a co-author on a published case report of orthokeratology-related Acanthamoeba keratitis in a 13-year-old, written with ophthalmology colleagues and published in Clinical and Experimental Optometry. We would rather families hear about that case from us, plainly, than not hear about it at all — because nearly all of the risk is preventable with habits we can teach in one appointment.
The water rules, for every ortho-k wearer:
- Never rinse lenses or the case in tap water, tank water or bottled water — only in the solution we prescribe.
- Never store lenses in anything but fresh solution, and never top up old solution.
- Dry hands on a clean towel after washing, before handling lenses.
- Take lenses out before swimming, showering, spa pools, rivers and lakes. If a lens is worn in water, discard the solution, clean and disinfect, and tell us.
- Air-dry the case upside down on a clean tissue, and replace it every three months.
Contact us the same day if an eye becomes red, painful, unusually light-sensitive, or vision drops — and mention that you wear ortho-k lenses. Acanthamoeba is often mistaken early on for a more ordinary infection, so pain out of proportion to what the eye looks like is worth saying out loud. Do not wear the lens again until it has been checked, and bring your lenses and case with you.
Orthokeratology and myopia control in children
For a child whose glasses prescription keeps increasing, ortho-k is one of several options we discuss alongside myopia control spectacle lenses and soft myopia control contact lenses. Which one is right depends on the child's prescription, age, eye health, sport and daily routine, and on what the family can realistically manage — including whether the water rules above can be followed every night. We measure axial length at reviews so the decision is based on your child's own numbers rather than on a general claim. See myopia control for the full picture.
Practical questions
- Does it hurt? No. Most people are aware of the lenses for the first few nights and then stop noticing them, because you are asleep for nearly all of the wearing time.
- How long does the effect last each day? For most wearers, all day. Some notice vision softening late in the evening, particularly at first, and the lens design can often be adjusted.
- What if I stop? Your cornea returns to its original shape and your previous prescription returns. Nothing is permanently changed.
- How long do the lenses last? Typically one to two years with good care, and they are replaced on a schedule we agree with you.
- Can my child swim while doing ortho-k? Yes — lenses out for swimming. That is one of the advantages: clear vision in the pool without lenses in the water.
- What does it cost? Fitting is quoted at your assessment, because it depends on the design and the number of visits your eyes need. We will tell you the full cost, including reviews and replacement lenses, before you commit.
Book an orthokeratology assessment in Hamilton
If you or your child would like to be assessed for ortho-k, start with the free chat or book a fitting directly:
- Not sure if it suits you? Shift / Ortho-K Free Chat — 15 minutes, no cost
- Ready to be fitted — New Ortho-K / Shift fit (30 minutes)
- Already wearing ortho-k — Orthokeratology / Shift full exam (30 minutes)
Or call us on 07 847 3195 or get in touch. We will tell you plainly whether ortho-k is the right option for your eyes, and if a different approach would serve you better, we will say so.
Rose Optometry, 38 Lake Road, Frankton, Hamilton. 07 847 3195
References
- Singh V, Lallu J, Ramachandran N, Kim BZ, McKelvie J. Orthokeratology-related Acanthamoeba keratitis in a 13-year-old. Clin Exp Optom. 2023;106(7):800-802. doi:10.1080/08164622.2022.2111203
Reviewed by Jagrut Lallu — BOptom (Hons), MSc Specialty Lenses (Hons), FIAOMC, Therapeutic Optometrist & Contact Lens Specialist, Partner, Rose Optometry. Last reviewed 27 August 2026.
Frequently asked questions
In NZ an optometrist can calculate the prescription for glasses, fit contact lenses, diagnose and treat eye conditions and infections with medication. They can also manage ocular injuries including removing foreign objects. If surgery or specialist treatment is required they can refer to an ophthalmologist (eye surgeon), hospital, or other health care specialist. NZ-trained optometrists must complete a 5-year degree at the University of Auckland before becoming registered.
A dispensing optician has formal training in optical dispensing. They are qualified to help a client choose frames, read a prescription, discuss lens options, take measurements, order and fit glasses.
An ophthalmologist is a medical doctor who has specialised in the treatment of serious eye disease and ocular surgery such as cataract removal. They do not typically prescribe glasses or contact lenses.
While payment is generally required on the day of appointment, we do offer a number of payment options including Afterpay, Genoapay, QCard, and GoCardless.
Yes, we do.
Yes, you can.
Yes, if you are under 16 years of age you may be eligible for a subsidy for glasses. MSD criteria apply.
No. We are closed on public holidays and long weekends as we believe our staff should have the chance to enjoy this time with friends and family.
If your eyes are straightforward, almost any good optometrist can look after you well, and we would rather say that than pretend otherwise. Come to us when something is not straightforward: a prescription that will not settle, a cornea that has changed shape, a child whose short-sightedness is moving faster than it should, an eye surface that has stopped being comfortable, or a diagnosis you have been given but do not understand. Those problems are decided by measurement, and measuring them properly needs instruments most practices do not have.
Yes, and you do not need to justify it. A second opinion is not a criticism of whoever saw you first — very often they were right, and what you actually needed was the finding explained and the numbers put in front of you. What we can add is measurement. We can image the layers of your cornea and retina, map the epithelium, quantify how far your cornea sits from normal, measure the length of your eye and check your tear film objectively. That turns “something is not right” into a number, and a number either explains the problem or rules it out. Bring any previous scans, prescriptions and letters. Comparison against your own past results is often the most valuable thing in the room.
Usually. Complex is what this practice was built around — keratoconus, corneal grafts, irregular corneas after surgery or injury, severe dry eye, high prescriptions, and eyes that have been told they are not fittable with contact lenses. The Rose K lens for keratoconus was designed in this practice, and lenses of that family are now the most frequently prescribed in the world for the irregular cornea. If we cannot help, we will tell you at the first appointment and tell you who can, rather than taking you through a course of treatment that was never going to work.
Not necessarily. “Not fittable” usually means not fittable with the lens designs and the measurements available at the time. Corneal mapping, epithelial thickness imaging and modern scleral and custom lens designs have moved a long way, and eyes that were genuinely unfittable ten years ago are often routine now. What we can promise is an honest answer after we have measured, not before.
Measure things that are usually not measured. Swept-source OCT of the cornea gives us tomography, full-thickness mapping, epithelial thickness mapping and an objective ectasia risk score. Retinal OCT with autofluorescence shows cellular-level change without any dye being injected. Optical biometry measures the length of the eye to a hundredth of a millimetre, which is how myopia is properly monitored. Objective tear film assessment and osmolarity replace guessing about dry eye. Most of these produce a baseline you can be compared against for the rest of your life, and that comparison is frequently worth more than any single result.
No. Anyone can book directly. Many of our patients are referred by their own optometrist, their GP or an ophthalmologist, and just as many simply ring us. A referral letter is useful because it saves repeating history, but it is not a requirement and it is not a condition of being seen.
No, and we would not build a referral practice on that basis. We accept referrals every week from optometrists across the Waikato and well beyond — Specsavers, OPSM, Bailey Nelson, Visique, For Eyes and independent practices alike. The patient comes to us for the part that needs our instruments or our lens work, and goes back to you with a written plan and the imaging. We are also glad to talk a case through before you refer, and if you have an OCT but no biometer we can help you get objective myopia measures out of the instrument you already own. Please contact us for co-management.
Waiting is the one thing that cannot be undone. Short-sightedness is axial — the eye is physically growing too long — and that length does not come back. What treatment does is slow the rate of growth, so the earlier it starts the more length is saved. We measure axial length directly on two independent biometers and plot it against normal growth curves, which means we can see a child drifting off their expected curve before the prescription changes. There is a free 15-minute myopia chat if you want to understand the options before committing to anything. It is worth being precise about what we are all trying to achieve. Myopia control does not stop a child's eyes changing and no practice should tell a parent it will. What it does, reliably and across many published trials, is slow the rate at which the eye lengthens — and because the risk of retinal detachment, myopic maculopathy and glaucoma in later life rises with every extra millimetre, slowing that growth is how a child is kept out of the range where sight is genuinely at risk. After seventeen years of focusing on this, we are now seeing children on customised plans whose axial length is not progressing at all over a monitoring period, and in some cases measurements that come back slightly shorter than the ones before them. That is our own clinical observation in our own patients rather than a trial result, and it has to be read carefully, because the choroid thickens when treatment is working and part of an apparent reduction can be that thickening rather than the eye itself shortening. That is precisely why we measure both. We are not yet able to tell a parent that we can stop myopia in its tracks, and we will not say it until we can.
Two things: we measure it before treating it, and we hold every current treatment technology in one building. Most dry eye is treated on the basis of symptoms, which is why drops so often fail. A tear film can be failing because the oil layer is blocked, because the water layer is short, because the surface is inflamed, or because the lids are the problem, and those need different treatments. We assess the tear film objectively with TearCheck — tear film stability, the oil layer, lid and gland imaging, and an inflammation measure — and measure tear osmolarity, the saltiness of the tears, which is the closest thing to a laboratory number for dry eye. Then we treat the cause. Rose holds intense regulated pulsed light for inflammation and gland function, LipiFlow thermal pulsation to clear blocked meibomian glands from the inner lid surface, Blephasteam controlled-humidity warming, Tixel thermomechanical treatment for the lids, and Rexon-Eye quantum molecular resonance for the more severe and treatment-resistant cases. At the time of writing, and to the best of our knowledge, no other optometrist or ophthalmologist in New Zealand has all of these available under one roof. We say that as a statement of fact rather than a boast, and we would be glad for it to stop being true. Dry eye is one of the most common and most under-treated conditions we see, and there are far more people living with it than one practice can look after. Any practice wanting to build this kind of service has our encouragement and our help — please contact us for co-management, and send us the cases you are not yet set up for. Why holding all of them matters is simple. A practice with one dry eye machine will offer you that machine. Holding all of them means the assessment decides the treatment, rather than the equipment deciding it — and when the first approach does not work, the next one is in the next room rather than in another city.
Yes — from around six weeks of age. Babies and toddlers are tested with Cardiff acuity cards and retinoscopy, neither of which needs the child to read a letter, name a picture or say a word. Most of the findings that matter in a young child cause no symptoms and are invisible to a parent, which is exactly why they need looking for.
There is one good reason: a baseline. Almost everything we look for — glaucoma, macular change, a cornea beginning to alter shape, an eye that is lengthening — is diagnosed by comparison over time rather than by a single reading. A scan taken while everything is normal is the reference every future scan is measured against, and it is the one you cannot go back and take later.
Because measurement takes time and we would rather not split it across visits. A first appointment usually involves imaging as well as examination, and you should expect to have the results shown to you and explained rather than summarised. If a problem is genuinely straightforward we will say so and keep it short.
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