week 4: sensory perception OBJ 2 and 3

What age-related changes can occur in the external eye?

• Loss of orbital fat

• Senile ptosis - drooping of the upper lip

• Lower eyelid changes

• Narrowing of the tear duct

• Reduced tear production

• Decreased goblet cells

What is the difference between ectropion and entropion?

• Ectropion → lower eyelid turns outward

  • increase risk of dryness of skin

• Entropion → lower eyelid turns inward

  • lashes scratch inner eye

Why can aging increase the risk of dry eye syndrome?

• Tear ducts become narrower

• Tear production decreases

• Goblet cells decrease

• Less mucin is produced

• Can cause irritation and inflammation

What is keratoconjunctivitis sicca?

• Another term for dry eye syndrome

• Causes irritation and inflammation of the eye

What age-related changes occur in the internal eye?

• Cornea → becomes more opaque

• Lens → becomes stiffer and more opaque

• Iris → becomes less flexible

• Pupil → becomes less responsive

• Ciliary muscle → atrophies and functions less

How does the cornea change with aging?

• Becomes more opaque

• Interferes with passage of light

• Can contribute to farsightedness (hyperopia)

How does the lens change with aging?

• Becomes stiffer

• Becomes more opaque

• Has a decreased ability to respond/change

How do the iris, pupil, and ciliary muscle change with aging?

• Iris → less flexible

• Pupil → less responsive

• Ciliary muscle → atrophies → less function

What happens to rods and their associated nerves with aging?

• The number of rods decreases

• Associated nerves at the peripheral retina also decrease

What vascular change can occur in the back of the eye with aging?

• Arteries may experience atherosclerosis

• blood not pumping as much

How does aging affect visual information processing?

• Neurons in the visual cortex can degenerate

• Visual information is processed more slowly

How does aging affect the visual field?

• The visual field becomes reduced

• The area that can be seen around the visual field decreases

• peripheral vision

How does aging affect depth perception?

• Depth perception decreases

• Makes locating objects more difficult

• Can increase fall risk

How can aging affect colour vision?

• Colours may appear altered

• Things can appear more yellow

What happens when critical flicker fusion is diminished?

• flashing light may appear continuous

How does aging affect visual information processing?

• Older adults may need more time to process visual information

• Teaching strategies should allow additional processing time

How does aging affect contrast sensitivity?

• Contrast sensitivity decreases

• It becomes harder to distinguish objects with similar shades

How does aging affect sensitivity to glare?

• Older adults become more sensitive to glare

• i.e. rain and ice

How does presbyopia affect vision?

• Loss of accommodation

• Difficulty focusing on close objects

• Caused by age-related changes in the lens

How does visual acuity change with aging?

• Visual acuity decreases

• Less detail can be seen clearly

• need to turn on more lights to see more

How does the amount of light reaching the retina change from age 20 to 60?

• It decreases about threefold

• Less light reaches the retina

How does aging affect dark and light adaptation?

• Adaptation becomes delayed

• More time is needed to adjust when moving between different lighting levels

How does aging affect sensitivity to glare?

• Glare sensitivity increases

• Changes in the pupil and vitreous contribute

How does aging affect contrast and visual detail?

• Contrast of viewed objects decreases

• Difficulty discerning fine details

• Can make reading more difficult

What activities can become more difficult with age-related visual changes?

• Reading

• Night driving

• Seeing fine details

What happens to vision with normal aging in the absence of disease?

• Age-related changes affect structures in the retinal-neural pathway

• Changes occur gradually

• Usually do not have a major effect on everyday activities

How can normal age-related vision changes be distinguished from disease?

• Normal aging → gradual changes with little effect on daily activities

• Disease → can cause more significant visual impairment

What questions can the nurse ask when assessing loss of vision function?

• When was your last eye examination?

• When did you first notice difficulty seeing?

• What could you do if you could see better?

• Have you stopped activities because of vision problems?

What safety questions should the nurse ask about vision impairment?

• Have you ever tripped or fallen because of trouble seeing?

• Is driving being affected?

• Are you missing traffic signs?

• Is driving at night becoming more difficult?

Why should the nurse ask about activities and driving when assessing vision?

• Identifies how vision loss affects daily functioning

• Identifies safety risks

• Helps determine whether vision problems are limiting activities

What should the nurse observe for when assessing visual impairment?

• Abnormalities of the eyelids

• Squinting

• Increased sensitivity to light

• Overall appearance

• Corrective lenses in good working condition

What behaviors may indicate visual impairment?

• Mis-stepping

• Sitting incorrectly or misjudging where to sit

• Walking into objects

What functional changes should the nurse assess for with visual impairment?

• Changes in ability to perform ADLs

• Changes in ability to perform IADLs

• Changes in independence

What are important cues that may indicate visual impairment?

• Eyelid abnormalities

• Squinting/light sensitivity

• Problems with corrective lenses

• Mis-stepping

• Walking into objects

• Changes in ADLs/IADLs

What should the nurse assess for when checking eye comfort?

• Mild dry eyes → dry, scratchy feeling

• Moderate dry eyes → discomfort or pain

• Decreased mucus production

What can contribute to dry eye discomfort with aging?

• Decreased mucus production

• Mucus production can be assessed by a physician

what are common age-related diseases

• glaucoma

• cataracts

• macular degeneration

What causes glaucoma?

• Build-up of aqueous fluid in the inner eye

• Causes increased intraocular pressure (IOP)

• Pressure damages the optic nerve

• Can lead to vision loss

What are risk factors for glaucoma?

• Increased age

• Genetic predisposition

• High blood pressure

• Diabetes

• Steroid use

• Previous eye injuries

What are the key features of primary open-angle glaucoma?

• Most common type

• Develops gradually

• Often affects peripheral vision first

• Can cause vision loss

• May cause tired eyes, headaches, or misty vision

What are the signs of acute closed-angle glaucoma?

• Medical emergency 🚨

• Severe eye pain

• Blurred vision

• Red eye

• Headache

• Nausea and vomiting

• Rapid increase in IOP

What is normal-tension glaucoma?

• Glaucoma where intraocular pressure is not as high

• Optic nerve damage can still occur

How is glaucoma assessed?

• Regular screening by an eye specialist

• Dilated-eye examination

• Tonometry to measure intraocular pressure (IOP)

What is tonometry used for?

• Measures intraocular pressure (IOP)

• Uses a tonometer

• May involve a “puff of air”

Why is regular glaucoma screening important?

• Glaucoma can progress slowly

• Regular eye-specialist screening helps detect it

What medication-related interventions are important for glaucoma?

• Adhere to the prescribed medication regimen

• Treatment can halt progression

• Be aware that steroids can exacerbate glaucoma

• Eye drops and oral medications may be used

• Beta blockers may be used

What other treatments may be used for glaucoma?

• Laser surgery may be recommended for some types

• Treatment depends on the type of glaucoma

What non-pharmacological interventions can help a person with glaucoma?

• Glare control

• Appropriate magnification

• Colour contrast to identify/find objects

What causes cataracts?

• Oxidative damage to lens proteins

• Fatty deposits in the ocular lens

• Causes the lens to become cloudy

What are risk factors for cataracts?

• Advanced age

• Smoking

• Prolonged sunlight exposure

• Diabetes

• Malnutrition

• Corticosteroid use

• Family history

What are common signs and symptoms of cataracts?

• Clouding of the ocular lens

• Halos around objects

• Blurred vision

• Decreased perception of light and colour

• Increased glare sensitivity

Are cataracts usually found in one or both eyes?

• Usually bilateral

• Can affect both eyes

When may cataract surgery be recommended?

• When vision creates safety risks

• When quality of life is affected

• Lecture notes: when visual acuity decreases to about 20/50

What post-surgical change may indicate retinal detachment?

• A “curtain” coming down over the line of vision

• This is an emergency

What is the nurse's role with cataracts?

• Recognize changes suggesting cataracts

• Refer for further assessment

• Provide education

• After surgery: teach precautions such as avoiding heavy lifting

Are cataracts usually found in one or both eyes?

• Usually bilateral

• Can affect both eyes

When may cataract surgery be recommended?

• When vision creates safety risks

• When quality of life is affected

• Lecture notes: when visual acuity decreases to about 20/50

What post-surgical change may indicate retinal detachment?

• A “curtain” coming down over the line of vision

• This is an emergency

What is the nurse's role with cataracts?

• Recognize changes suggesting cataracts

• Refer for further assessment

• Provide education

• After surgery: teach precautions such as avoiding heavy lifting

What are risk factors for cataracts, and what may reduce the risk?

• Excessive sunlight exposure

• Poor diet

• Diabetes

• Hypertension

• Kidney disease

• History of alcohol or tobacco use

• Higher intake of lutein + zeaxanthin may reduce risk

• Vitamins C and E, copper, and zinc may also reduce risk

• Lutein/zeaxanthin sources: yellow or dark leafy vegetables

What happens in age-related macular degeneration (AMD)?

• Degenerative disease affecting the macula

• Macula is responsible for central vision

• Early stage → photoreceptor cells become disrupted

• Later stage → choroidal blood vessels can hemorrhage

• Severe disease can lead to total blindness

What are the risk factors for AMD?

• Advanced age

• Family history

• Smoking

• Obesity

• Sunlight exposure

What are key assessment findings for AMD?

• Loss of central vision

• Amsler Grid can help detect changes

• Wavy/distorted lines may indicate early macular changes

How is AMD managed?

• No cure

• Medications

• Laser-based treatments

• Antioxidant vitamins may be used

What is the nurse's role with AMD?

• Ongoing evaluation

• Rehabilitation therapy

• Teach patient to use Amsler Grid daily

what is the Amsler Grid used for?

• used to assess central vision

• helps detect changes associated with macular degeneration (AMD)

• recommended to put on fridge and look at it everyday

  • if one day it looks abnormal seek immediate care

What did the research study find about lutein and zeaxanthin?

• Participants who took lutein + zeaxanthin

• Without beta-carotene

• Had a reduced risk of developing advanced AMD

What are the key vision findings for glaucoma, cataracts, and AMD?

• Glaucoma → ↑ intraocular pressure + peripheral vision loss

• Cataracts → clouding of the lens

• AMD → degeneration of macula + loss of central vision

What interventions help prevent vision impairment or vision loss?

• Minimize sunlight exposure

• Avoid smoking

• Good nutrition and exercise

• Nutrients: vitamins C/E, beta-carotene, zinc, copper

• Lutein supplements (10 mg/day may lower AMD risk)

• Regular eye examinations

• Control medical conditions

• Consider access/cost of treatment

How can nurses help reduce the impact of vision changes?

• Fall prevention

• Provide eye comfort

• Artificial tears/ocular lubricants

• Cold compresses

• Humidity

• Check for adverse drug reactions

What interventions can improve function when a person has visual changes?

• Make environmental modifications

• Use contrasting colours

• Provide proper lighting

• Increase colour contrast

• Control glare

• Use fall-reduction protocols

• Example: Two red nail-polish dots can help distinguish temperature settings

• black and white is the best contrast

What environmental aids can help a person with visual impairment?

• Maintain/use prescribed eyewear

• Magnifying glasses

• Low-vision aids

• Large-print materials

• High-contrast materials

• Plain, easy-to-read fonts

• Use soft 60–75 watt bulbs for reading

• Provide about 3× as much light

• Avoid glare

• Use brightly coloured tape at the top of stairs

What interventions can promote eye comfort for dry eyes?

• Use artificial tears/eye drops

• Apply cold compresses

• Maintain adequate environmental humidity

• Avoid eye irritants

• Review medications for possible causes

What are population-level health outcomes for vision?

• Reduce risk of pathological eye conditions

• Education can reduce disease rates

• Encourage younger people to: (primary level)

  • Wear sunglasses

  • Get adequate nutrients

What are individual-level health outcomes for vision?

• Early detection → early treatment

• Reduce visual loss from pathological conditions

• Improve vision and functioning

• Reduce risk of falls

• Improve eye comfort