In this observational study, the investigators recruite patients referred at the Glaucoma Service of the Ophthalmologic Clinic of the ASST Sette Laghi University Hospital in Varese.~All the patients enrolled in the study require a reliable (less than 15% of false positive or false negative and no more than 33% of loss of fixation) visual field examination (Humphrey SITA 24-2 or 30-2 SITA Standard) performed in the previous six months.~All patients undergo a full ophthalmologic examination and verbally submitted a questionnaire designed by the authors of the paper (LL, SD, MD).~The examination included Visual Acuity, refraction, slit lamp bio-microscospy, Goldmann's applanation tonometry, gonioscopy with four mirror lens, OCT RNFL and GCL imaging if necessary and re-evaluation of target IOP.~The investigators use the two monocular visual fields to build an Integrated Visual Field which, according to D.P. Crabb papers, is an efficient surrogate to the Binocular Esterman Visual Field Test (EVFT). In short, each point in each monocular field is compared to its equivalent in the other eye, and the data, from the eye with the best sensitivity, are used. Locations are dichotomized into groups with sensitivity > 10 dB and < 10 dB, representing whether a patient would see or miss a point in the Esterman test, respectively. To match even better the IVF with the EVFT, 8 points of the inner 20° of the IVF were excluded since they have no direct equivalent in the EVFT.
The aim of the study is to identify clinical criteria, easily achievable with patient's follow-up tests, which can identify individuals at increased risk of being unfit to drive. Only they, then, will be directed to further investigations. These clinical standards should also be suitable for implementing or substituting the current law's criteria, after appropriate additional studies, so that the law can be based on the clinic.