👁 What is Central Corneal Thickness (CCT)?

👁 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.

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🔍 Clinical Importance of CCT

1. Refractive Surgery Planning
   • Determines suitability and surgical safety
   • Overestimated CCT → Risk of overcorrection or ectasia
   • Underestimated CCT → Patient wrongly deemed ineligible
2. Glaucoma IOP Correction
   • Goldmann tonometry is affected by corneal thickness
   • CCT adjustment required for accurate pressure readings
   • Essential for patients with LASIK history + glaucoma

 

 

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🧪 Measurement Methods

Device TypeExamples

Ultrasound (Contact)	A-scan
Non-contact Optical

• AS-OCT: Cirrus, Spectralis
• Topography: ORBscan, Pentacam, Galilei
• Laser Biometry: IOL Master, Lenstar |

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📏 Normal CCT Range

• Textbook: 525–530 μm
• Real-world range: 525–550 μm
• ⚠ Machine-dependent variability → Use the same device for follow-ups

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🔬 Key Korean Studies

YearSubjectsCCT Range

2015	25 adults	Slight inter-device variation
2016	180 adults	Roughly 525–550 μm

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✅ 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