A reduced ability to see detail - reduced ‘visual acuity’,
Photophobia which is sensitivity of the eyes to light,
Nystagmus which is an involuntary rapid movement of the eyes,
Strabismus that can have both visual and cosmetic affects. The
eyes do not work together effectively when focusing (fixing) on an object, particularly when an object is moving (‘tracking an object’). The pupils may appear to point in towards the nose or outwards to the sides
Refractive errors such as long and short sightedness and Astigmatism (distortions to the shape of images projected onto the retinas.
Most people are able to register as sight impaired (partially sighted) or severely sight impaired (blind) with social services in the UK. Registration may be helpful for accessing some additional social services, disability benefits, and aspects of income tax. For children in education registration may be helpful evidence if parents or schools wish to apply for a statement of special educations need (SEN).
In the UK very few people with either HPS or OCA are legally able to drive on public roads.
All the above features are discussed on the following pages. Although discussed separately these features can interact with one another. For instance a reduced ability to see detail is made worse by nystagmus which prevents the eyes from fixing and focusing on one particular point
Visual Impairment of Hermansky-Syndrome
The visual impairment of HPS is very similar to that of OculoCutaneous Albinism (OCA). It is caused by a lack of a pigment (Melanin) during the development of the foetus in the womb. The lack of melanin prevents some parts of the eyes from developing and maturing during this critical period. The retinas and nervous system of the eyes (the optic nerves or pathways) are particularly affected.