Tistoryview
π What is Central Corneal Thickness (CCT)?
CCT refers to the thickness of the central cornea,
playing a critical role in refractive surgery screening and intraocular pressure (IOP) correction in glaucoma patients.
π Clinical Importance of CCT
- Refractive Surgery Planning
- Determines suitability and surgical safety
- Overestimated CCT → Risk of overcorrection or ectasia
- Underestimated CCT → Patient wrongly deemed ineligible
- Glaucoma IOP Correction
- Goldmann tonometry is affected by corneal thickness
- CCT adjustment required for accurate pressure readings
- Essential for patients with LASIK history + glaucoma
π§ͺ Measurement Methods
Device TypeExamples
| Ultrasound (Contact) | A-scan |
| Non-contact Optical |
- AS-OCT: Cirrus, Spectralis
- Topography: ORBscan, Pentacam, Galilei
- Laser Biometry: IOL Master, Lenstar |
π Normal CCT Range
- Textbook: 525–530 μm
- Real-world range: 525–550 μm
- β Machine-dependent variability → Use the same device for follow-ups
π¬ Key Korean Studies
YearSubjectsCCT Range
| 2015 | 25 adults | Slight inter-device variation |
| 2016 | 180 adults | Roughly 525–550 μm |
β Summary
- CCT is vital for refractive screening & glaucoma management
- Normal range: ~525–550 μm
- Be cautious of differences between devices
- Use same device consistently for monitoring