Contents



**III**

**Chapter 17 285**

**Chapter 18 301**

**Chapter 19 323**

**Chapter 20 347**

**Chapter 21 359**

Audio Cortical Processing in Blind Individuals

*and Claudio Campus*

*by Susanne Zimmermann-Janschitz*

*by Giovanni Sato and Roberta Rizzo*

Low-Vision Rehabilitation in Maculopathy

Biometric Systems and Their Applications

Eye Movements during Barking at Print *by Tanya Beelders and Angela Stott*

*by Souhail Guennouni, Anass Mansouri and Ali Ahaitouf*

*by Monica Gori, Maria Bianca Amadeo, Giulio Sandini* 

The Application of Geographic Information Systems to Support Wayfinding for People with Visual Impairments or Blindness


Preface

Blindness defines either the best-corrected distance visual acuity or presenting distance visual acuity in the better eye. Different visual acuity levels are commonly used to better define blindness ranging between < 20/400 and < 20/200 in the better eye. In contrast, visual impairment defines a visual acuity of 20/60 or less in the

The prevalence of blindness varies considerably among developed countries. Socio-economic factors are linked to available health and eye care services and thus influence prevalence. For example, a 0.25 prevalence of blindness among the general population living in a well-developed country may translate to a 1.25 prevalence in a country with poor socio-economic status and health care. Differences in prevalence are also due to blindness being secondary to several diseases and conditions, such as cataracts, refractive errors, and corneal scarring (trachoma, corneal infections, and vitamin A deficiency). Visual impairment and blindness is an important public health problem that requires affordable, high-quality clinical and diagnostic capacity, good therapeutic approaches, and

In this book we provide an overview of the effects of blindness and visual

impairment in the context of the most common causes of blindness in older adults and children. These causes may include retinal disorders, cataracts, glaucoma, and

> **Giuseppe Lo Giudice, MD** San Paolo Ophthalmic Center,

National University of La Plata,

San Antonio Hospital, University of Padua, AOPD,

Italy

**Angel Catala**

Argentina

better eye.

rehabilitation.

macular and corneal degeneration.
