Unit 7 Ch 19 Disorders of visual fxn Part II

Goals of strabismus treatment

Development of normal visual acuity correction of the deviation superimposition of the retinal image to provide binocular vision

Nonproliferative diabetic retinopathy Common complaint

confined to retina, engorgement of retinal veins, thickening of capillary endothelial basement membrane, macular edema, sensation of glare

visual agnosia

extensive damage to visual association cortex that surrounds an intact primary visual cortex; results in a loss of the learned meaningfulness of visual images

Saccadic eye movements

jerky conjugate movements that quickly change the fixation point, used in reading

Visual assessment of infants/children younger than 3 years of age includes

1) can each eye fixate on an object 2) maintain fixation 3) follow the object in various positions *Should be completed binocularly and monocularly

Two causes of amblyopia

1) inadequately developed CNS circuitry bc of visual deprivation (ex cataracts) 2) abnormal binocular interactions (ex strabismus) during visual immaturity

3 layers of neurons in the retina

1) posterior layer of photoreceptors 2) middle layer of bipolar cells 3) inner layer of ganglion cells that communicate with the photoreceptors

Four types of retinal detachment & which is the most common

1. exudative 2. traction 3.rhegmatogenous** (most common) 4. combined traction/rhegmatogenous

Proliferative diabetic retinopathy

Characterized by formation of new fragile blood vessels which bleed easily, can lead to retinal detachment

Blood supply for retina (2)

Choriocapillaris (capillary layer of the choroid) Branches of the central retinal artery

metamorphoosia -what is it -if present, can be aid in early detection of what?

Distorted vision of straight lines retinal damage

T/F small-range optical tremors are abnormal

FALSE They are normal and useful independent function of each eye

T/F A vitrectomy (removal and replacement of the vitreous with a balanced saline solution) is of value if the retina is not functioning properly

False Vitrectomy is of NO value if retina is not functional May restore sight in ppl w/ vitreous opacities

hemianopia vs quadrantanopia

Hemianopia = half of the visual field for one eye is lost quadrantanopia = quarter of the visual field is lost for one eye

The nurse is conducting a community education class on amblyopia. The nurse determines that the participants understand the concepts when they identify which time period as the time when amblyopia is generally diagnosed?

Infancy Explanation: Amblyopia (i.e., lazy eye) is a decrease in visual acuity resulting from abnormal visual development in infancy and early childhood.

An infant with an abnormal red reflex requires what?

Immediate referral to an eye care specialist

Teaching points for diabetic patient in preventing blindness

Importance of yearly eye exams Tight control of blood glucose levels Keep BP below 130/85 (American Heart Association Guidelines)

Most common presenting sign of retinoblastoma Second most common sign Late sign(s)

Leukokoria (cat's-eye reflex, white reflex, white pupil) Strabismus red, tearing, and painful eyes, limited/poor vision

Most common type of strabismus

Nonparalytic estropia (individual ocular muscles have no obvious defect)

cortical blindness

bilateral loss of the entire primary visual cortex

An older adult client comes to the clinic complaining of seeing flashing lights and small spots. The client tells the nurse that this has been going on for over 24 hours but now it is as if there is a dark curtain whenever the client opens the eyes. The client asks the nurse if this means that blindness is imminent. What diagnosis should the nurse suspect?

Retinal detachment Explanation: The primary symptom of retinal detachment consists of painless changes in vision. Commonly, flashing lights or sparks followed by small floaters or spots in the field of vision occur. As the detachment progresses the person perceives a shadow or dark curtain across the visual field.

2 types of photoreceptors in retina

Rods = black white Cones = color discrimination

A mother brings her toddler to the clinic and tells the nurse that she thinks something is wrong with the baby's eyes. Upon further assessment the nurse notices that the child has upper deviation in movement in only one eye. What diagnosis should the nurse suspect for this child?

Strabismus Explanation:Strabismus, or squint, refers to any abnormality of eye coordination or alignment that results in loss of binocular vision.

T/F untreated retinoblastoma can be fatal

TRUE If untreated, children can die of intracranial extension and disseminated disease

Binocular vision depends on the coordination of how many pairs of extraocular nerves that provide for the conjugate eye movements?

Three Explanation:' Binocular vision depends on the coordination of three pairs of extraocular nerves that provide for the conjugate eye movements, with optical axes of the two eyes maintained parallel with one another as the eyes rotate in their sockets.

Anopia

blindness in one eye

The macula lutea is especially adapted for _____ and is composed entirely of _____

acute and detailed vision cones

retinitis pigmentosa

hereditary, progressive disease marked by night blindness with atrophy and retinal pigment changes.

heteronymous hemianopia

loss of different half-fields in the two eyes

Paralytic strabismus causes

paresis (weakness) or plegia (paralysis) of one or more of the extraocular muscles

Perimetry used to determine what? How?

presence, size, and shape of smaller holes (or scotomata) in the visual field of an eye Maps sensitivity contours of the visual fields

smooth pursuit movements

tracking movements that serve to maintain an object at a fixed point in the center of the visual fields of both eyes. The object may be moving with the eyes following, or the object may be stationary with the head moving.