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(nighttime contact lens)
slow down myopia + daytime spectacle free

Orthok / nighttime contact lens

Orthokeratology (nighttime contact lens)

(OrthoK, OK-lens, Corneal Refractive Management, Corneal molding)

The information below is a general review of the concept of orthokeratology lens. You may  call us (Tel: 21530008) for detail information.


What’s Orthokeratology?

Orthokeratology (Orthok) is a non-surgical nighttime vision correction by use of contact lens to reshape cornea. Orthok can provide your spectacle free vision. It can be an alternative to daytime contact lens and refractive surgery. Orthokeratology (Orthok) is also method for myopia control and dry eye management. By use of a series of highly oxygen transmissible rigid contact lenses, the cornea will be molded and flatten at night under supervision of optometrist. Orthokeratology is effective in reducing moderate myopia and astigmatism in day time. In addition, scientific research demonstrated that orthokeratology may stop or retard the myopia progression [1]. It is also used for handling dry-eye people for contact lens purpose.

Aim of Orthokeratology:

1. *daytime spectacle free

2. myopia control

3. contact lens option for dry eye cases


Nighttime contact lens

*daytime spectacle free

Orthokeratology mechanism

In modern accelerated orthokeratology, the cornea is molded by the specially built highly oxygen permeable contact lens in close eye condition. Orthokeratology needs high accuracy of corneal profile assessment for matching nighttime contact lens with eye. It is guided and monitored by state of the art corneal topographer (a kind of shape and profile scanner). The corneal shape modification and accuracy can be reviewed immediately.

sMap3D orthok.jpg

Precision Optics Corneal Topographer

•  32 Rings 
•  102,000 Analysed Points
•  9600 Measurement Points 
•  Composite Mapping Coverage 0.25mm to 14mm
•  Extrapolated Data Out to 17mm
•  Power Range 10 - 100 Diopters

sMap3D orthok 2.jpg
sMap3D orthok 3.jpg
orthokeratology reduced 6D myopia
Candidate for Orthok

Help children enjoy fun of reading

Who are suitable for orthokeratology process?

- at least 7 years old
- Less than -6.00D of myopia and with less than -2.00D of astigmatism. (For those with corneal astigmatism higher than -1.50D, toric / astigmatism orthokeratology lens may be needed)
- Myopia are progressing rapidly.

- Sports and water sports enthusiastic, e.g. swimming, diving, skiing.
- For those not suitable for LASIK refractive surgery

- For those with dry eye problem associated with soft contact lens

Myopia Damages Eyes

orthok induced defocus control myopia

1. *Good vision can usually be maintained throughout the day after lens removal.
2. Recent research has shown the usage of Ortho-K to be effective in slowing myopic progression in children [1] .
3. Ortho-k can reduce myopia of 5.00D within two weeks. However, individual variation does exist.
5. Complications associated with conventional contact lens wear, such as dryness and irritation from dust can be avoided.
6. Safe alternative to LASIK laser refractive surgery with no wounds and no dry eyes.
7. The Orthok-K effect is reversible and can be stopped anytime. The eyes will soon resume their normal condition thereafter.

1. Ortho-k is NOT a CURE for myopia. The Ortho-K effect will wear off gradually after cease of lens wear.
2. Aftercare consultations are necessary to ensure effectiveness and safety.
3. Some contact lens-related problems, such as solution sensitivity, infection, corneal epithelial trauma or ulceration may occur, though the risk of complication is very dependent on compliance.

orthokeratology schedule

Attention! *Daytime vision quality may be affected by various factors. Wearer may still have chance to need spectacles with low power for some visual purpose. Remember complications can happen anytime! Minimize the chance of these complications through good communication with your optometrist, strict compliance and regular aftercare consultations. Parents of children who are unable to handle their contact lenses hygienically should be prepared to do these for their children, or if not, SHOULD NOT allow their children to undergo Ortho-k usage.

1. Cho P, Cheung SW. Protective Role of Orthokeratology in Reducing Risk of Rapid Axial Elongation: A Reanalysis of Data From the ROMIO and TO-SEE Studies. Invest Ophthalmol Vis Sci 2017;58(3):1411-1416.

orthok orthok

**Case Examples:

**Case Example 1.:

- Calvin had myopia -2.50 binocularly. Since 1o years old, he put on nighttime contact lenses (orthokeratology lenses) every night. At daytime, after removal of lenses, his residual prescription was around farsighted +0.75 to +1.00. He achieved functional vision without spectacles at daytime.

- Eight years later, he went to USA for university education. The nighttime contact lens wearing frequency was reduced to four times per week.
- At 18 years old, Calvin's myopia was right eye -2.50, left eye -2.75.

Portrait of a young Asian boy wearing tr
Case examples

**Case Example 2.:

- Joan had myopia -3.50 binocularly. Since 13 years old, she put on nighttime contact lenses (orthokeratology lenses) every night. At daytime, after removal of lenses, his residual prescription was around farsighted +0.50 to +0.75. She achieved functional vision without spectacles at daytime. 

- Five years later, she went to Australia for medical school training. The wearing frequency of nighttime contact lenses was reduced to five times per week.
- At 22 years old, Joan's myopia was maintained -3.50.

Doctor and Asian young woman looking at
Active woman in her 50s running and jogg

**Case Example 3.:

- June had myopia -5.00 and presbyopia (reading problem) +2.00. since 50 years old, she cannot tolerate soft contact lenses because of severe dryness.

-  By use of nighttime orthokeratology lenses, she can manage her driving and reading tasks without spectacles. Her residual prescription was usually +0.25 to +0.50 for right eye and -0.75 for left eye.

-   She was very happy without need of reading glasses.

**To comply with privacy regulation, the aforementioned case information was modified.

Our optometrists


More services

Eye Exam

Our Centre provides eye test for Adults and children from two and half years old. The eye test covers refractive errors, visual functions and eye health assessment.

​Progressive spectacle lenses + Multifocal contact lenses

We are well experienced  in progressive spectacle lenses and multifocal contact lenses fitting for management of presbyopia.

Myopia control & Orthokeratology


our centre also provide myopic control and orthokeratology service to kids and teenagers on indication.

Specialty contact lens services

In our center, we fit specialty contact lenses, such as rigid gas permeable (RGP) lenses, hybrid lenses and scleral lenses.

​Health Care Voucher

Our optometrists are appointed Health Care Service Providers of Health Care Voucher Scheme. Eligible Elderly may use Health Care Voucher for payment of eye examination and eyeglasses fee. For more information, you may contact us by telephone number 21530008 for eye examination booking.

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