3.1 Ocular nutrition, deficiencies, and toxicology

what are the macronutrients?

carbs

proteins

lipids

water

fiber

Carbohydrates

- body converts into ...

- function

- glucose

- quick energy

Carbs types

simple carbs

complex carbs

fiber

Proteins function

components of skin, muscle, enzymes

body needs how many AA's to live?

20

how many AA's are essential?

9

Complete protein vs incomplete protein

has all 9 essential AA's vs doesn't

Lipids aka fatty acids

- function

- energy storage, cell membranes, steroid hormones

Types of lipids

saturated, unsaturated, trans fat

Saturated lipids

- def

- _____ at room temp

- ______ products

- no double bonds in C chain

- solid at room temp

- animal products

Unsaturated lipids def

- def

- ______ at room temp

- what types of foods

- at least one double bond in C chain -- cis configuration

- liquid at room temp

- oils

Trans fat

- def

- ______ at room temp

- what types of foods

- at least one double bond in C chain--trans configuration

- semi-solid at room temp

- animal products, processed food

Micronutrients includes what?

vitamins and minerals

Organic vitamins characteristics

- break down when heated

- shorter shelf life

Types of vitamins

fat soluble and water soluble

Fat soluble vitamins

- Storage

- how often do they need to be consumed?

- which vitamins?

- body stores in liver/fatty tissue

- not as regularly as water soluble

- A, D, E, K

Water soluble vitamins

- storage?

- which vitamins?

- less easily stored in body

- B and C

Types of minerals

Major minerals and trace minerals

What are major minerals

Magnesium, calcium, phosphorus, sulfur, sodium, potassium, choride

Phytonutrients definition

protective compounds found mainly in plants--chemicals created by plants to resist infection/infestation

Phytonutrients

- are they essential?

- 2 main ones

- no

- Lutein, zeaxanthin

Explain antioxidants

- substance that neutralizes free radicals in the body

- reactive oxygen species are normal by-products of oxygen metabolism -- increased with environmental stressors

How are supplements regulated by FDA?

same way food is regulated -- can't make medical claims

Recommended Dietary allowance (RDA)

avg daily level of intake sufficient to meet nutrient requirements of nearly all healthy people

Adequate Intake (AI)

- level assumed to be adequate

- established when there's not enough evidence to set RDA

Tolerable Upper Intake Level (UL)

Max daily intake unlikely to cause adverse health effects

Factors in nutrition include ...

- bioavailability of nutrients

- some nutrients affect absorption of others

- "Antioxidant orthodox" (antioxidants don't seem to prevent disease but eating foods rich in them does)

- Vitamin toxicity in high doses

Vitamin A

- _____philic

- types

- lipophilic

- preformed and provitamin

Preformed vit A

- example

- high amts in ________

- retinol

- animal products, especially liver

Provitamin

- example

- present in ...

- beta carotene

- leafy green veggies and yellow veggies/fruits

Vit A Functions

- Immune response

- helps form critical component of rhodopsin (chemical photoreceptors use to detect light)

- maintains conjunctival/corneal epithelium

Vit A deficiency

- risk factors

- inadequate intake

- cystic fibrosis

- malabsorption

What is leading cause of preventable blindness in children worldwide?

Vit A deficiency

Vit A deficiency ocular manifestations

Xerophthalmia

- night blindness, ocular dryness (not sight threatening and sight threatening), Xerophthalmic fundus

Which photoreceptor depends on Vit A completely to detect light?

Rods

Xerophthalmia ocular dryness not sight threatening

- 3 things

- conjunctival xerosis

- Bitot's spots

- Corneal xerosis

Conjunctival xerosis def

conjunctiva appears dull, wrinkled

Bitot's spots def

triangular patches with bubbles (temporal>nasal)

Corneal xerosis def

cornea appears dull, lazy

Ocular dryness--sight threatening 2 things

- corneal ulcer/keratomalacia

- corneal scar

Xerophthalmic fundus

- what is this?

small white deep retinal lesions

typically outside arcades

rare, prolonged Vit A deficiency

Preformed Vit A excess manifestations

- pseudotumor cerebri (intracranial pressure increases for no real reason)

- bilateral papilledema (ONH edema)

Chronic beta carotene supplements -- downside?

increased lung cancer risk in smokers

Thiamine (Vit B1)

- ______ philic

- functions

- hydrophilic

- many roles in metabolism and protein synthesis

- role in normal functioning of CNS, digestive system, heart, immune cells

Thiamine deficiency (Vit B1) risk factors

- inadequate intake

- chronic alcoholism

- malabsorption

- people with HIV/AIDS

- older adults

Thiamine deficiency (Vit B1) most common manifestation

Beriberi

2 types of Beriberi

Dry and Wet

Dry Beriberi -- what Is this ?

- affects CNS

- degeneration of long nerves leading to numbness, parasthesias (tingling/pricking), burning pain

Wet Beriberi -- what is this?

- affects CV system

- peripheral edema, high risk for heart failure

Thiamine deficiency (Vit B1) Wernicke Encephalopathy Triad

- Encephalopathy, Gait ataxia, Ophthalmoplegia/nystagmus

Wernicke Encephalopathy Triad -- the catch

clinical triad may not be present in up to 90% of Thiamine deficiency patients

Encephalopathy definition

disorientation, inattentiveness, memory impairment

Gait ataxia defintion

Wide based gait, inability to stand

Ophthalmoplegia/nystagmus main thing

horizontal gaze evoked nystagmus

Folate and Vit B12 -- hard to differentiate them

- ______ philic

- can be stored where?

- hydrophilic

- liver

Functions folate and Vit B12

- development/function/myelination of CNS

- development of RBCs

- DNA synthesis

Folate/B12 deficiency risk factors

- alcohol abuse

- inflammatory bowel disease

- pernicious anemia

- veganism

- age>75

Folate/B12 deficiency ocular manifestation

optic neuropathy

- bilateral

- reduced VA

- poor color vision

- wedge defect in NFL

- cecocentral VF defect

Vit D

- _____ philic

- 2 types

- major source

- lipo

- D2 produced by plants

- D3 produced by animals

sunlight (UV-B)

Vit D functions

- aid in Ca absorption

- maintains serum Ca and phosphate

- anti-inflammatory

Vit D deficiency risk factors

- limited sun exposure

- darker skin

- condition that limits fat absorption

- obesity

- gastric bypass surgery

Vit D insufficiency is a risk factor for many ___________

autoimmune diseases

Selenium

- what is this?

- functions

- trace mineral present in soil

- reproduction/fertility

- thyroid hormone metabolism

- DNA synthesis

- antioxidant

Selenium deficiency risk factors

- area with selenium poor soil

- kidney dilaysis

- + for HIV

Selenium supplementation can improve symptoms for ...

patients with thyroid eye disease

Dry eye is characterized by ...

tear hyperosmolarity

inflammation

Current treatment for dry eye

- stabilizing tear film

- reducing inflammation (steroids)

What vitamins can be effective for dry eye?

topical vit A and omega-3 fatty acids

Topical Vit A for dry eye

- how does it help

- improve goblet cell density

- improve dry eye syndrome

Omega 3 fatty acids for dry eye

- how does it work?

- reduces inflammation

- improves function of meibomian glands

3 types of omega-3 fatty acids

- EPA, DHA, ALA

EPA -- from what and function

- fish

- anti-inflammatory

DHA -- from what and function

- fish

- boosts brain health

ALA -- from what and function

- walnuts/flaxseed

- body converts to DHA/EPA

Most formulations of omega 3 fatty acids for dry eye have what ratio of EPA/DHA?

1.5-2:1

What supplements can help with cataracts?

- antioxidant vitamins in diet (Vit E, C, A)

AMD is characterized by ...

- drusen

- RPE dropout

- choroidal neovascularization

AREDS AMD study categories 1, 2, 3, 4 meaning

1 -- no AMD

2 -- start of AMD

3 -- moderate AMD

4 -- severe AMD

In smokers, beta carotene can do what?

increase risk of lung cancer

AREDS study supplements to reduce AMD

- for patients with Cat 3 or 4 AMD, the formulation can help them reduce risk of progression to advanced AMD

AREDS2 formula

- vit C and E

- zinc

- copper

- lutein

- zeaxanthin

Lutein/Zeaxanthin

- supplements can do what in retina ?

improve macular pigment optical density and VA

Glaucoma and supplements -- is there evidence?

not yet--developing

Chloroquine and hydroxychloroquine use

- treat/prevent malaria

- treat rheumatic diseases

Hydroxy -- chloroquine ocular toxicity

- corneal verticillata

- retinopathy

What is corneal verticillata?

- pigmented whorl keratopathy at level of epithelium -- need to distinguish from whorl keratopathy in Fabry disease

Early stages of retinopathy in Chloroquine/hydroxychloroquine

- outer retinal thinning parafoveally need OCT to identify

Late stages retinopathy Chloroquine/hydroxychloroquine

Bull's eye maculopathy

Chloroquine/hydroxychloroquine retinopathy

- changes are _______

- retinopathy lasts until when?

- permanent

- can continue for some time after discontinuing drug

Chloroquine/hydroxychloroquine

- recommended monitoring schedule for retinopathy

- obtain baseline tests

- monitor at 5 years, and yearly after

- OCT, visual fields need to be done

For OCT chloroquine/hydroxychloroquine, what to look for?

look for thinning of parafoveal outer retinal layers with loss of photoreceptor integrity line

Chloroquine/hydroxychloroquine monitoring tests--Visual Fields

- what is recommended for everyone?

- 10-2 for parafoveal defects

- 24-2 or 30-2 for Asian patients

Chloroquine/hydroxychloroquine management

- if retinopathy is found, notify PCP

- Patient will need to stop drug and use replacement

- continue to monitor retinopathy

Ethambutol

- use

- ocular toxicity

- treatment of TB

- optic neuropathy within 1-3 months of onset of med

Ethambutol optic neuropathy symptoms

- blurry/cloudy vision

- color vision changes

- difficulty reading

Ethambutol optic neuropathy clinical signs

- reduced acuity

- VF defects

- color vision defects

- fundus exam often normal

Ethambutol recommended monitoring schedule

- obtain baseline tests

- monitor every 1-2 months

- VA, color vision, visual fields (24-2 or 30-2)

Ethambutol management

- if optic neuropathy is found, notify PCP

- patient needs to stop drug use

- continue to monitor for several months

Isoniazid

- use

- ocular toxicity

-treatment of TB

- optic neuropathy

- very similar to ethambutol related optic neuropathy -- monitor and manage the same

Amiodarone

- use

- ocular toxicities

- treat/prevent ventricular arrhythmias

- corneal verticillata and optic neuropathy