Disorders Of Visual Functions Flashcards
Conjunctiva *
Mucous around eye
Conjunctivitis *
Redness and swelling of the clear membrane
Conjunctiva Disorders*
Infectious
- bacterial
- viral
- chlamydial
- opthalmia neonatorum (baby’s eyes are contaminated during passage through birth canal from infected mother)
Presbyopia*
Change in vision due to aging (thickened lens and less elastic muscle fibres)
Glaucoma*
Increased introcular pressure which leads to loss of vision or blindness
Open-Angle Glaucoma*
Wide angle and open but drainage canals are clogged overtime causing an increase in pressure and damage to optic nerve
Angle-Closure Glaucoma
Narrow angle, sudden increase in intraocular pressure. Fluid is continually produced and drains out of eye
Cataracts*
Clouding of lens
Causes of Cataracts *
- aging
- genetic, environmental, metabolic influences
- drugs
- injury
- diabetes
- long term exposure to sunlight
- heavy smoking
- secondary to trauma or disease
Ectropion*
Lower lid is loose and rolls out
Ectropion Causes*
Muscle weakness
Facial paralysis
Scars or previous surgery
Genetic disorders
Entropion
Lower lid rolls in
Optic nerve
Connects to brain; sends signals
Tears
Protective film that hydrates the eyes
Deterioration of tear film from:
Aging
Loss of reflex lacrimal gland secretion
Contact lenses
How to treat deterioration of tear film?
Artificial tears
Plug lacrimal puncta
Ointments
Lacrimal
Drainage of eyes
Hordeolum
Infection if sebaceous gland (aka stye)
Amblyopia
Diminished vision with no detectable organic eye lesion of eye
Strabismus
Abnormality of eye coordination resulting in binocular vision
(Paralytic strabismus - muscle is impaired)
Abducens nerve
Lateral eye movement
Trochlear
Down and inwards (superior obliques)
Oculomotor
Up, down, medial, up and in
Pupil size is controlled by?
Autonomic nervous system
- parasympathetic controls constriction
- sympathetic controls dilation
Uveal tract
Middle vascular layer
Anopia
Blindness in one eye
Hemianopia
Loss of half of visual field in one eye
Quadrantanopia
Quarter of visual field lost in one eye
Heteronymous hemianopia
Loss of half-fields in two eyes
Aqueous humor
- maintains intraocular pressure
- mediates exchange of respiratory gases
- provides nutrition to lens and cornea
- low protein
- high acid, glucose, amino acids
Primary Visual Impairment
No evidence of preexisting ocular or systemic disease
Secondary Visual Impairment
Associated with other inflammatory process affecting eye
Ischemia
Inadequate blood supply to eye
Papilledma
Increased pressure in brain causing optic nerve to swell
Retinal Vein Occlusion
Blockage of veins that carry blood away from retina
Retinal Artery Occlusion
Blockage where blood flows into eye artery
Diabetic Retinopathy
Vision loss due to diabetes
- nonproliferative: confined to retina
- proliferative: formation of new fragile blood vessels
Retinal Detachment - Exudative
From accumulation of fluid in sub-retinal space
Retinal Detachment - Traction
From scar tissue
Retinal Detachment - Rhegmatogenous
Most common type where vitreous begins to liquefy and collapse
Macular Degeneration
Dry form - atrophic (waste/decrease in size)
Wet form - exudative (leaking/oozing)
Visual Agnosia
Loss of learned meaningfulness of visual images
