Anisometropia: Treatment Options in Korea
What is anisometropia?
Anisometropia is a condition in which the two eyes have significantly different refractive errors: one may be much more nearsighted, farsighted or astigmatic than the other, or one eye may be nearsighted and the other farsighted. Small differences are very common and cause no trouble; larger ones can affect comfort, depth perception and, in children, visual development.
It has the same underlying causes as other refractive errors: differences in eye length or corneal curvature between the eyes. It can also follow surgery or injury to one eye, or a cataract that develops faster on one side. For the basics of each error, see our guides to myopia, hyperopia and astigmatism.
Why can glasses feel uncomfortable with anisometropia?
Spectacle lenses of very different strengths make the images seen by each eye slightly different in size, which the brain can struggle to fuse. People describe eye strain, headaches, a feeling that the floor is tilted, or simply that glasses never feel right.
Contact lenses usually reduce this effect because they sit on the eye, which is why many people with anisometropia rely on them. When contact lenses become uncomfortable or impractical, refractive surgery becomes attractive.
How does anisometropia affect children?
In children it can cause amblyopia. The American Academy of Ophthalmology (AAO) explains that when one eye has a much worse refractive error, the brain comes to rely on the better eye and suppresses the weaker one. Because vision seems normal with both eyes open, it is easy to miss.
The AAO says amblyopia treatment works best before about age 7 or 8. It combines glasses with patching or blurring drops for the stronger eye, and usually takes months. This is why vision screening in early childhood matters.
How is anisometropia diagnosed?
A full eye exam measures the prescription of each eye separately, with and without dilating drops, and tests best-corrected vision in each eye. Before surgery, Seoul clinics also map both corneas, measure corneal thickness and, for lens options, the internal dimensions of each eye. The exam will show whether one eye has amblyopia, which affects what surgery can achieve. See the pre-op eye exam guide.
Which treatments in Seoul address anisometropia?
In adults, each eye can be treated to its own prescription, so the eyes end up closer to each other. The method can even differ between eyes.
| Situation | Usually considered | Seoul price (2026) |
|---|---|---|
| Both eyes within laser range, healthy corneas | LASIK, LASEK or SMILE on each eye | ₩1.5M–₩3.2M both eyes |
| One eye has high myopia or a thin cornea | ICL in that eye, laser or ICL in the other | ICL ₩4M–₩6.5M both eyes; ask for a one-eye price |
| Astigmatism mainly in one eye | Laser or toric ICL | Toric ICL ≈₩5M–₩7.5M both eyes |
| Over about 45, or cataract in one eye | Lens exchange or cataract surgery | ₩1.5M–₩6.5M per eye |
| Children | Glasses or contacts, amblyopia treatment | Not surgery |
What can surgery achieve if I have a lazy eye?
Surgery can remove the need for unequal glasses, but it cannot restore vision lost to amblyopia in adulthood. If your weaker eye could only read a few lines with glasses before surgery, expect roughly the same best vision afterwards.
Many adults still find surgery worthwhile because it removes the image-size mismatch of glasses and the hassle of contacts. Discuss realistic goals with the surgeon, and ask how they will handle a small residual difference. The AAO's general candidacy criteria for LASIK, including a stable prescription and healthy corneas, apply to each eye; see Am I a candidate for LASIK?
Can I have surgery on only one eye?
Yes. If one eye already sees well, a surgeon may treat only the other. Single-eye prices are not always half the both-eye price, so ask for a written quote. If both eyes need treatment with different methods, for example SMILE in one and an ICL in the other, the clinic will price each separately. See ICL vs SMILE and high myopia options.
What about presbyopia and monovision?
People over 40 with anisometropia sometimes already have natural monovision: one eye sees far and the other near. Correcting the near eye fully can take that away and make reading glasses necessary. If you like your current balance, say so; a surgeon may deliberately leave one eye slightly nearsighted. See monovision LASIK and our presbyopia guide.
What are the risks?
The risks are the same as for each procedure: dry eye, glare and halos, and under- or over-correction after laser surgery; and raised eye pressure, cataract and other intraocular risks after an ICL, as the U.S. FDA describes for phakic lenses. Because the eyes start out unequal, a small error in one eye can leave you aware of an imbalance, and an enhancement may be needed. Read LASIK side effects.
This page is general information, not medical advice. An ophthalmologist must examine both eyes before recommending any procedure.
What should I ask before treatment?
- What is the best-corrected vision in each eye, and is there amblyopia?
- Will both eyes be treated the same way, and what will the price be for each?
- What result are you aiming for in each eye?
Bring any childhood records of patching or lazy-eye treatment if you have them.
Sources
Key facts
- What it is: a significant difference in prescription between the two eyes
- Main childhood risk: amblyopia (lazy eye), best treated before about age 7–8
- Adult options: laser surgery on each eye, or an ICL in the stronger eye
- Limit: surgery cannot restore vision lost to adult amblyopia
- Exam first: pre-op eye exam in Korea
Related guides
General information, not medical advice. Only a full eye exam by a licensed ophthalmologist can confirm your diagnosis and which treatment is safe for you.
FAQ
Frequently asked questions
Can LASIK fix anisometropia?
Often, yes, in adults whose eyes are both within laser range. Each eye is treated to its own prescription, which removes the difference between them.
Why do my glasses make me dizzy?
With very different lens strengths, each eye sees an image of a slightly different size. Contact lenses or surgery usually reduce this effect.
Can surgery fix a lazy eye?
Refractive surgery corrects the prescription but cannot restore vision lost to amblyopia in adults. Amblyopia treatment works best in childhood, before about age 7 or 8.
Can I have ICL in one eye and LASIK in the other?
Yes, if your exam supports it. Surgeons sometimes combine methods when one eye has a much higher prescription or thinner cornea.
How much does it cost to treat one eye in Seoul?
It varies by clinic; single-eye prices are often more than half the both-eye price. Ask for a written per-eye quote.
Planning vision correction in Seoul?
Compare clinics by district, check 2026 price ranges, and read our step-by-step planning guide for international patients.