Investigation of Intraocular Pressure Changes Due to Different Serum Level Heights by Using Tonopen in Acquired Globes from the Iran Eye Bank

Purpose: To investigate intraocular pressure (IOP) changes due to different serum level heights by using Tonopen in acquired globes from the Iran Eye Bank (IEB).Methods: In this interventional prospective case series, serum were infused into 18 normal globes acquired from IEB by using 21G needle inserted in vitreal space through optic nerve head to change the IOP by different fluid level heights from the globe surface. IOP of globes were measured and recorded by Tonopen over the sclera and over the cornea at different serum level heights.Results: Twelve globes were acquired from male donors and 6 globes were from female donors. Mean age of donors were 57 year old. Mean measured pressures by Tonopen of the 18 globes at the serum level heights of 13.6, 27.2, 40.8, 54.4 and 68 cm from the globe surface were 14, 23.6, 34.8, 44 and 52.8 mmHg over the sclera and 13.1, 22.8, 34.8, 44.1 and 52.8 mmHg over the cornea respectively.Conclusion: Using a Tonopen is a proper method to measure the acquired globes IOP, except in serum level height of 13.6 cm (10 mmHg) from the globe surface. In addition, if tonometry over the cornea is not available, it can be done by using Tonopen over the sclera