Study wants to test reliability Dynamic Contour Tonometry (DCT) in measuring intraocular pressure (IOP) and Ocular Pulse Amplitude (OPA). IOP values obtained with DCT will then be compared with IOP values obtained with Goldmann Applanation Tonometry (GAT), actually the gold standard technique.

Healthy volunteers recruited among subjects who underwent a routine ophthalmologic evaluation or among students and workers both at our clinic, will undergo a series of 5 DCT to evaluate eventual differences among the measurements.

A diurnal IOP curve performed though GAT, composed of 3 measurements (9am, noon, 4pm) will be taken 1 to 7 days before the DCT.

At the end of the DCT measurements a last GAT will be taken to control eventual IOP changes versus previous GAT values obtained through the diurnal curve.

After 3 weeks observers will contact patients to record eventual adverse events. If examiners consider it as necessary, a safety ophthalmological evaluation will then be performed.

Inclusion Criteria:

• healthy subjects giving a valid consent to be included in this experimentation
• age between 18 and 80 years
• best corrected visual acuity (BCVA) of at least 20/100
• refraction ranging from -6 to +6 dioptres, with an astigmatism ranging from -2 to +2 dioptres

Exclusion Criteria:

• History of refractive surgery or any keratoplasty procedure.
• Corneal opacities or diseases making no suitable applanation tonometry.
• Use of contact lenses. History of glaucoma or ocular hypertension.
• History of diabetic retinopathy staged as severe non-proliferative or worse.