What Does It Mean To Be Corrected

UNIVERSITY OF LAGOS, COLLEGE OF MEDICINE, IDI-ARABA, LAGOS DEPARTMENT OF BIOMEDICAL ENGINEERING

A PROJECT WORK ON WEARABLE OBSTACLE SENSOR FOR VISUALLY IMPAIRED

By

OGUNSANYA, ABIODUN OLAYINKA (139099011) & OKOI, OMINI EYONG (139099007)

SUMITTED TO THE DEPARTMENT OF BIOMEDICAL ENGINEERING, FACULTY OF BASIC MEDICAL SCIENCE, COLLEGE OF MEDICINE, IDI-ARABA, LAGOS

IN PARTIAL FUFILLMENT OF THE REQUIREMENTS FOR DEGREE OF MASTER OF SCIENCE (M Sc. Hon) IN BIOMEDICAL

Visual information is the basis for most navigational tasks, so visually impaired individuals are at disadvantage due to the lack of sufficient information about their surrounding environment. With recent advances in inclusive technology it is possible to extend the support given to people with visual disabilities in terms of their mobility. Visual impairment is one of the most common disabilities worldwide. WHO estimated around 39 million blind people, the largest number of visually impaired people falls into the senior citizen category; in fact 82% of people with impaired vision are over 50 year and above. Globally, uncorrected refractive errors are the main cause of moderate and severe visual impairment; cataracts remain the leading cause of blindness in middle and low income countries. The number of people visually impaired from infectious diseases has reduced in the last 20 years according to global estimates work. 80% of all visual impairment can be prevented or cured [4]. The following terms are used to describe the different levels of visual

The human eye is a slightly asymmetrical globe, very complex and truly amazing organ. It is approximately 2.54cm wide and deep, and 2.286cm tall. Human eyes allow humans to appreciate all the beauty of the world they live in, to read and gain knowledge, and to communicate their thoughts and desires to each other through visual expression and visual arts. The human eye is wrapped in three layers of tissue: the external layer, formed by the sclera and cornea; the intermediate layer, divided into two parts: (anterior and posterior) and the internal layer or the sensory part of the eye, the retina [10].

Figure 1: Diagram of Human Eye with Major Structures [10]

2.1 GENERAL DESCRIPTION OF THE MAJOR STRUCTURES OF THE HUMAN EYE

Sclera

The sclera is the tough, outermost layer of the eye. The white membrane of the sclera maintains the shape of the eye.

Cornea

The cornea is a transparent structure located at the very front of the eye that helps to focus incoming light. The moist and dust-free cornea admits light to the interior of the eye and bends the light rays to that they can be brought to a focus.