Today we are going to talking about the relationship between Intraocular pressure and cornea thickness.

【Intraocular pressure】
The Intraocular pressure refers to the aqueous pressure, expressing by mmHg as the difference between atmospheric pressure, with the normal value of 10〜21 mmHg. Aqueous humor is produced by the ciliary body, fills the anterior chamber to keep the shape of eyes, supplying the nutrients, excretes waste products, but if the flow becomes poor, the Intraocular pressure will increase.

【Cornea thickness】
Central cornea thickness is an important part of Ophthalmological diagnose.
Usually, the average number of Japanese is around 520〜540μm.

The cornea thickness affects the actual intraocular pressure reading. If the cornea is thick, the measured value may be higher than the actual value, and if it’s thin, the reading value will tend to be lower than the actual reading.

Intraocular pressure is measured by applying pressure to the cornea using the non-contact tonometer, but with the cornea becomes thicker, the resistance will increase, resulting in an overestimated intraocular pressure.

When diagnosing the ocular hypertension, to avoid this ‘apparently high value’, it is important to measure the corneal thickness and calculate the corrected Intraocular pressure.

If the cornea is thick, even the normal Intraocular pressure can be measured higher, which may lead to over estimation of glaucoma risk.

If the cornea becomes thinner, such as after the LASIK surgery, so the true Intraocular pressure need to be valued by the corrected formula （e.g. the Ehlers formula）.

For an accurate diagnose, the Ophthalmologists also use corneal thickness measurement (such as the anterior segment OCT).