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Role of nutrition to prevent ocular disorders
1. Role of nutrition to prevent ocular
disorders
Sahibzada Hakim Anjum Nadeem
Co-Incharge OTTC, Optician, Refractionist, COAVS
CEO Anjum Eye Care & Optical Company
Optometrist, Al-Khair Eye Hospital Lahore
Phone:03344496480, Email: shanjum92@gmail.com
3. Nutrients
Chemical substances that constitute food
and are responsible for the functions of
food and also protect the body from
various disorders.
4. Types of nutrients
There are two types of nutrients.
I.Macronutrients
âProteins
âcarbohydrates
âFats
II.Micronutrients
âVitamins
âMinerals
5. Introduction of Vitamins
Vitamins may be regarded as organic
compounds required in the diet in small
amounts to perform specific biological
functions for normal maintenance of
optimum growth and health of the
organism.
6.
7. WHAT IS VITAMIN A?
⢠The term âvitamin Aâ makes it sound like there is one particular
nutrient called âvitamin Aâ, but this is not true. It is a broad group of
related nutrients.
⢠Vitamin A is a broad term for group of unsaturated nutritional
organic compounds, that includes retinol, retinal, retinoic acid, and
several provitamin A carotenoids, among which beta-carotene is the
most important.
8. Vitamin A is an Essential Fat soluble vitamin
occuring in the following forms:
ďPre formed
ďRetinoids (retinal, retinol, retinoic acid)
ďFound in animal products
ďPro vitamin A
ďCarotenoids
ďMust be converted to retinoid form
ďFound in plant products
9. HISTORY:
ďIt is recorded in history that HIPPOCRATES
cured night blindness(about 500 B.C)
ďHe prescribed to the patients Ox liver(in
honey)which is now known to contain high
quantity of vitamin A.
ď By 1917, Elmer McCollum at the University of
WisconsinâMadison, studied the role of fats in
the diet and discovered few accessory factors.
These "accessory factors" were termed "fat
soluble" in 1918 and later "vitamin A" in 1920.
10. ďąIn 1919, Harry Steenbock (University of
Wisconsin) proposed a relationship between
yellow plant pigments (beta-carotene) and
vitamin A.
ďąIn 1931, Swiss chemist Paul Karrer described
the chemical structure of vitamin A.
ďą Vitamin A was first synthesized in 1947 by
two Dutch chemists, David Adriaan van
Dorp and Jozef Ferdinand Arens.
11. Structure of vitamin A:
NOMENCLATURE:
ďPROVITAMIN A : β-Carotene
ďVITAMIN A1 : Retinol ( Vitamin A alcohol)
ďVITAMIN A2 : 3 -Dehydro-retinol
ďVITAMIN A ALDEHYDE : Retinal
ďVITAMIN A ACID : Retinoic acid
ďVITAMIN A ESTER : Retinyl ester
ďNEO VITAMIN A : Stereo isomer of Vitamin A1, has 70 â80% of
biological activity of Vitamin A1.
12. Sources of vitamin A:
⢠Animal : Fish Liver oil, Butter, Milk,
Cheese, Egg Yolk
⢠Plant : All Yellow âOrange âRed âDark
Green fruits & vegetables like Tomatoes,
Carrots, Spinach, Papayas, Mangoes,
corn, sweet potatoes.
13.
14.
15. RECOMMENDED DIETARY ALLOWANCE
ď Unit of activity is expressed as âRETINAL
EQUIVALENTâ (R.E.) / âINTERNATIONAL UNITâ
(I.U.)
ď1 Retinal Equivalent = 1Îźg of Retinol OR 6 Îźg
of β-carotene
ď1 I.U. = 0.3 Îźg of Retinol OR 0.34 Îźg of Retinyl
acetate OR 0.6 Οg of β-carotene
Infants & Children : 400 t0 600 Îźg/day
Adults (Men & Women) : 600 to 800 Îźg/day
Pregnancy & Lactation : 1000 to 1200 Îźg/day
16. FUNCTIONS OF VITAMIN A:
ď VISION
ď GENE TRANSCRIPTION
ď IMMUNE FUNCTION
ď EMBRYONIC DEVELOPMENT AND REPRODUCTION
ď BONE METABOLISM
ď HAEMATOPOESIS
ď SKIN AND CELLULAR HEALTH
ď ANTIOXIDANT ACTIVITY
⢠Recent work suggests that, outside the retina, vitamin A is chiefly
concerned with mucopolysaccharide synthesis and stability of
lysozome membranes. Children aged three months to four years
are most commonly affected.
17. METABOLISM
â˘LIVER STORES 90% OF VITAMIN A
â˘ACTIVE METABOLITES
â˘TRANS RETINOIC ACID
â˘CIS RETINOIC ACID
â˘REGULATES EXPRESSION OF KERATIN AND
MUCINS
â˘RHODOPSIN IN VISUAL CYCLE
18.
19. VITAMIN A DEFICIENCY:
ďMost susceptible populations:
ďPreschool children
ďOlder adults
ďAlcoholism
ďLiver disease (limits storage)
ďFat malabsorption
20. Vitamin A deficiency may result from :
ďDietary insufficiency of Vitamin A /
Precursors
ďInterference with absorption from intestines
ďeg: diarrhoea, malabsorption syndrome, bile
salt deficiency
ďDefect in the transport due to protein
malnutrition ââKwashiorkarâ
ďDefect in the storage due to diseases of liver
21. ďTissues chiefly affected ââEpithelialâ
principally which are not normally
keratinized.
ďIncludes epithelium of respiratory tract,
gastrointestinal tract, genitourinary tract,
eye & paraocular glands, salivary glands,
accessory glands of tongue & buccal cavity
and pancreas.
ďFundamental change: Metaplasia of normal
non-keratinised living cells into keratinising
type of epithelium.
22. OCULAR MANIFESTATIONS OF VITAMIN A
DEFICIENCY
ďXEROPHTHALMIA
The term Xerophthalmia was given by a
joint WHO and USAID committee in 1976 to
cover all the ocular manifestations of
vitamin A deficiency including the
structural changes affecting the
conjunctiva, cornea and retina and also the
biophysical disorders of retinal rods and
cones functions.
24. XN :NIGHT BLINDNESS(Nyctalopia)
ďEarliest symptom of xerophthalmia in
children
ďDiminished visual acuity in âdim
lightâ(Insufficient adaptation to darkness)
ďDefective rhodopsin function.
25. â˘Night blindness,is not pathognomonic of
vitamin A deficiency, being also a feature
of various eye diseases e.g. retinitis
pigmentosa, Oguchi's disease,
choroideremia, gyrate atrophy of the
choroid and retina, onchocerciasis and
occasionally congenital.
⢠If nutritional in origin the symptom will
disappear after consumption of about
30,000 I.U. of vitamin A daily
administered as cod or halibut liver oil.
26. X1A CONJUNCTIVAL XEROSIS
ďCharacterised by:
ďOne or more patches of dry, lusterless ,
nonwettable conjunctiva.
ďInterpalpebral conjunctiva(commonly temporal
quadrants)
ďSevere cases involves the entire bulbar
conjunctiva.
ďDesribed as âemerging like sand banks at receding
tideâwhen child ceases to cry
ďCan lead to conjunctival thickening,wrinkling and
pigmentation.
27.
28. X1B BITOTâS SPOTS
ďBilateral
ďBulbar conjunctiva in the interpalpebral area
ďCommonly in temporal quadrant.
ďRaised triangular greyish/silvery white spots/plaques.
ďFirmly adherent to conjunctiva
ďFoamy keratinised epithelium(corynebacterium
xerosis)
29. X2 CORNEAL XEROSIS
ďDry lustreless appearance of cornea
ďEarliest change is punctate keratopathy
ďBegins in the lower nasal quadrant
ďBilateral punctate corneal epithelial erosions
ďCan progress to epithelial defects
ďReversible on treatment
30. X3A & X3B CORNEAL ULCERATION
ďStromal defects occur in late
stages due to colliquative
necrosis leading to corneal
ulceration ,softening (melting)
and destruction of
cornea(keratomalacia)
ďCorneal ulcers may be small or
large
ďStromal defects involving less
than 1/3rd cornea usually heal
leaving some useful vision
ďLarge stromal defects
commonly result in blindness.
32. XS CORNEAL SCAR
ďHealing of stromal defects results in corneal
scarring
ďSize of the corneal scar depends on the size and
density of corneal defect.
33. XF XEROPHTHALMIC FUNDUS
ďUncommon in occurence
ďTypical seed like lesions
ďWhitish/yellow in colour
ďRaised lesisions
ďScattered uniformly over fundus
ďAt the level of optic disc.
ďFFA reveals these dots to be focal retinal pigment epithelial
defects
ď Rarely these patients can present with scotomas
corresponding to the area of retinal involvement
ďRespond to vitamin A therapy with scotoma disappearing in
1-2 weeks and retinal lesions fading in 1-4 months
34.
35. 2. Parenteral therapy: IN CASES OF
⢠severe disease
⢠unable to take oral feeds
⢠Repeated vomiting and diarrhoea
⢠malabsorption
ďIntramuscular injections of water miscible
vitamin A preparation
ďDose â 1,00,000 IU(Half the oral dose)
36. PROPHYLAXIS AGAINST XEROPHTHALMIA
ď1.Short term approach:
-Periodic administration of vitamin A supplements
-WHO recommended,universal distribution schedule of vit A for
prevention is as follows:
37. ď2.Medium term approach:
- fortification of food with Vit A
ď3. Long term approach:
- Promotion of adequate intake of Vit A rich foods
in high risk groups particularly preschool aged
children on a periodic basis and to mothers within
6-8 weeks after childbirth
- Other measures like nutritional education,social
marketing, home or community garden programs
and measures to improve food security.
38. HYPERVITAMINOSIS A
ď Ingestion of large amounts of preformed vitamin A from the diet,
supplement intake or medications;
I.Acute:
ď Single doses of >3,00,000 IU
ď Headache ,Blurred vision,nausea ,vomiting, drowsiness,irritability i.e
signs of raised ICP(Benign intracranial hypertension)
ď Serum Vit A values-200-1000 IU/dl
II.Chronic â long-term megadose; possible permanent damage
( >50,000 IU/day for several weeks)
ď Bone and muscle pain,Loss of appetite,Skin disorders
ď Headache
ď Dry skin
ď Hair loss
ď Increased liver size
ď Manifestations reversible when vitamin A discontinued
39. DEFICIENCY OF VITAMIN B1{THIAMINE}
â˘Can result in Corneal anaesthesia
â˘Conjunctival dystrophy
â˘Corneal Dystrophy
â˘Acute Retrobulbar neuritis
40. DEFICIENCY OF VITAMIN B2{RIBOFLAVIN}
I.FUNCTIONS- plays an important role in cellular growth
⢠It acts as a co â factor for a number of enzymes involved in energy
metabolism.
II.SOURCES:
⢠Eggs , liver, green leafy vegetables
⢠Milk
III.Deficiency may cause;
⢠Keratitis
⢠Susceptibility of cataract
⢠Photophobia
⢠Burning Sensation
⢠Conjunctival irritation
⢠Vascularization of Cornea
41. DEFICIENCY OF VITAMIN C
⢠It may be associated with haemorrhages in the conjunctiva, lids, anterior
chamber, retina and orbit.
⢠It delays wound healing
⢠It causes bleeding of gum
⢠Effective anti-oxidant
⢠Protects eyes against u.v rays
⢠Delays cataract formation < more than 300 mg>
SOURCES:
⢠Citrus
⢠guava
⢠mango
⢠Amla
⢠Pineapple
42. DEFICIENCY OF VITAMIN D
â˘It may be associated with Zonular Cataract
â˘Papilledema
â˘Increased lacrimation
44. OMEGA -3- FATTY ACID
I.Functions:
â˘Essential fatty acid used to produce new cells ,
muscle, nerves and organs
â˘Protects against ARMD, dry eye syndrome
II.Sources:
â˘Fish
⢠walnut
⢠flax seeds
45. ZINC
â˘This trace mineral has a protective effect on early
ARMD
â˘Acutely concentrated in the eye and hence very
important
Sources:
â˘Almonds
â˘Wheat germs
â˘Dairy