Ortho-K (Shift Lenses)

Orthokeratology, or ortho-k, 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 ortho-k 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.

Who ortho-k 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 the fitting process works at Rose Optometry

1. 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.
2. Trial lenses. We fit trial lenses in the practice, check the fit on the eye, and order your lenses.
3. 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.
4. 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.
5. 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.

Ortho-k 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 ortho-k assessment in Hamilton

If you or your child would like to be assessed for ortho-k, 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.

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 16 August 2026.