Nightblindness and xerophthalmia

about xerophthalmia, nightbliness, signs, symptoms, differential diagnosis, classification, diagnosis, management, prophylaxis, treatment

1. NIGHTBLINDNESS
AND
XEROPHTHALMIA
Raju Kaiti
Consultant Optometrist
Dhulikhel Hospital, KU

2. Definition
•Also termed as ‘nyctalopia’
•It is defined as diminution of vision in dim light
•It occurs due to defect in transition from photopic
to scotopic vision
•Apart from adaptation of mainly photoreceptor
rods and then cones, the neural adaptation
mechanism also plays role in dark adaptation

3. Causes
•Retinitis pigmentosa (RP)
•Vitamin A deficiency
•Gyrate atrophy of choroid and retina
•Congenital stationary night blindness (CSNB)
•Choroidermia
•Myopia

4. Other causes of Nyctalopia
•Glaucoma
•Optic nerve atrophy
•Cortical cataract
•Panretinal photocoagulation
•Zinc deficiency
•Drugs – phenothiazine, chloroquine,
hydroxycholoquine

5. Myopia
•Myopic patients also complain of night
blindness which may be the most common
cause of poor night vision
•However it is should not confused with blurring
of vision in dim light as seen in all refractive
disorders
•In very high myopes degenerative changes in
choroid and retina lead to subnormal ERG and
delayed dark adaptation

6. RETINITIS PIGMENTOSA
•Most frequently seen retinal dystrophy
•The term "retinitis" pigmentosa -Donders(1855)
•The term "pigmentary degeneration"-von
Graefe(1858)
•"Pigmentary retinal dystrophy" -appropriate term
Pathology
•Degeneration of retinal neuroepithelium
•particularly of rods
•Degeneration of entire retina, RPE, and also
choriocapillaris

7. CLINICAL PRESENTATION:
•Symptomatic onset
between age of 5-30 yrs
may occur in 4th or 5th
decades
•Symptoms:
Difficulty in seeing at
night
Daily-life handicap
•Sign
Clinical triad- Retinal
arteriolar
narrowing
Bony spicules
Optic disc pallor

8. Clinical features of RP
•Incidence in 1:4000
•Night blindness is one of the hallmark symptoms in RP
which usually begin in first or second decade of life
•Visual field loss is second hallmark of RP which is
insidious and progressive
•Central vision loss
•Light flashes
•Loss of color vision
•Hearing loss – associated in 30 % RP patients

9. Clinical Findings
Other Findings:
•Lens- Opacity , PSCC type
•Vitreous-Condensations, opacities,
cells, PVD
•Macula- Early broadening or
loss of the F. R.
Epiretinal membrane
changes
Pigment epithelial
alterations-mottling, bull's eye,

atrophy, pigmentation
• Macular oedema
• Full thickness holes

10. Vitamin A deficiency
•Primary cause of childhood blindness in Nepal
•Night blindness is a very sensitive although not
very specific indicator of vitamin A deficiency
•Vitamin A forms rhodopsin also known as visual
purple present in photoreceptor rods
•The sensitivity of rods is approximately
proportional to antilogarithm of rhodopsin
concentration
•Deficiency hence impairs functioning of photoreceptor
rods leading to night blindness

11. CHOROIDEREMIA
•X-linked recessive disease
•Granularity and depigmentation of the RPE
can be seen around the peripheral fundus.
•Full-field ERGs are reduced in amplitude and
delayed in b-wave implicit time with minimally
increased dark-adaptation thresholds, and full
visual fields

12. CH
O
RO
ID
EREM
IA

13. CHOROIDEREMIA
In more advanced stages dark-adaptation
thresholds are further increased and the visual fields
become constricted;
Female carriers of this disease may demonstrate
fundus changes that include patchy depigmentation
of the RPE.
However, carriers typically retain normal visual
acuities and normal final dark-adapted rod
thresholds

14. GYRATE ATROPHY OF CHOROID
AND RETINA

15. GYRATE ATROPHY OF CHOROID
AND RETINA
inherited by an autosomal recessive mode of
transmission
Patients usually present in early adolescence
with night deficiency and loss of peripheral
vision.
Ocular findings include myopia, constricted
visual fields, elevated dark-adaptation
thresholds, reduced ERG responses and
chorioretinal atrophy distributed circumferentially
around the peripheral fundus

17. Stationary forms of night
blindness
•Life long stable abnormality of scotpic vision having
early onset
Subtypes:
•CSNB with normal fundus
•CSNB with abnormal fundus
CSNB with normal fundus
•X-linked
•AD
•AR

18. Stationary forms of night
blindness
•CSNB with normal fundus
X-linked –commonest
• genetic defect- locus Xp11, mutation in rhodopsin
gene
• Defect is lies in the failure of communication
between proximal ends of photorecetors and bipolar
cells
• some pts. Do not c/o nyctalopia( way of life)
•Nystagmus decrease VA or myopia
•Range of VA- Normal to 6/60

19. CSNB
•CSNB with abnormal
fundus
Fundus Albipunctatus
(AR)
Oguchi’s Disease (AR)
Mizuo’s phenomenon

20. Approach to NB
Taking History ( complaints)
1.Night blindness
(How do they present to us?)
Progressive (RP)
Stationary (CSNB)
Sudden( paraneoplastic process)
Age of onset – imp. Younger (x-linked RP, CSNB)

21. Contd…..
2. Visual loss :
Gradual , progressive
Age of onset
3.Visual field constriction:
peripheral or central
How can they present to us?

22. Medical History
•Operations ( Intestinal surgeries, removal of
polydactyl)
•Liver diseases
•Use of medicine- Hydroxycholoquine or
phenothiazine
•Hearing status( RP, Usher’s Syndrome,choroideremia,
Refsum’s)
•Mental retardation( BBS,LMS)
•Renal disease (BBS)
•Heart disease (KSS, Refsum’s)

23. Family History
•Any NB in past 3 consecutive generation
(Dominant RP)
•Anyone in the family affected by retinal
degeneration
•Consanguinity

24. General Examination
wt. loss- vit A deficiency
truncal obesity –(Bardet-
Biedl Syndrome)

25. Systemic evaluation:
CVS- Kearn-Sayre Syndrome( ECG- Heart block)
P/A- Colostomy, surgical scars
ENT- Hearing loss ( Usher’s, RP, Choroideremia)
NS – Mental retardation( Bardet-Biedl Syndrome, Gyrate
Atrophy Choroidermia, LMS) ,Spastic paraplegia (LMS)
Urogenital- hypogenitalism( Bardet- Biedl syndrome)
Musculo-Skeletal –Polydactyl (Bardet- Biedl syndrome,
LMS), muscle weakness(Gyrate Atrophy), deformity
(Choroidermia)
Skin – Melanoma ( paraneoplastic cause)

26. Ocular Evaluation
Visual Acuity
EOM ( external ophthalmoplegia- KSS, Bassen-Kornzweig,
Refsum’s)
Lid ( ptosis- KSS)
Lens – PSCC- ( RP, Choroideremia, Gyrate Atrophy)
Vitreous – fibrillar changes ( Choroideremia), PVD( Gyrate
Atrophy)
Fundus-Normal or Abnormal
Normal fundus ( CSNB)
Refractive Status
Myopia- ( RP,choroideremia, Gyrate Atrophy)
High Myopia ( CSNB)
Astigmatism-( RP)

27. Fundus Changes in cases of NB
•RP
Choroide
remia
Gyrate atrophy

28. Fundus Changes
Oguchi

29. Investigations
•Visual fields( All)
•Dark Adaptometry
•ERG( all)
•Color vision( later stages of RP)
•Biochemical:
Ser. Vit A level
Ser. Lipoprotein( Bassen – Kornzweig syndrome)
Ser. Phytanic acid level ( Refsum’s)
Ser. Ornithine level( Gyrate Atrophy)

30. Management
Staging ( current VA, VF, dark adaptation, color vision, rod-
cone ERG)
Give devices for maximizing remaining vision
Monitoring Disease progression- 2yrs.-VF,ERG,Va
Counseling – Genetic + Vocational
Medical T/T:
Vit. A, Acetazolimide, Docosahexanoic acid(DHA)-
trial( RP)
Vit A, K, E( Bassen- Kornzweig)
Vit B6 ( Gyrate Atrophy)

31. XER
O
PH
TH
ALM
IA

32. Definition:
•Xerophthalmia is the general term applied to
all the ocular manifestations of impaired
Vitamin A metabolism, from night blindness
through complete corneal destruction

33. XEROPHTHALMIA
•Xerophthalmia
•Xeros --- Dry
•Ophthalmia --- Eye
•literally means “dry eye,”
•Many causes of dry eye but conventionally
Xerophthalmia has become synonymous
with vitamin A deficiency.

34. RDA: 5000 IU for men
4000 IU for women
Sources: liver, egg yolks and dairy products, tomatoes,
yellow and green leafy vegetables, and fish liver oils.
Vitamin A helps the eyes , the skin and the
development of healthy teeth and bones.
we can also battle stress with enough of this vitamin.
Deficiency will also make susceptible to infection

35. Risk Factors
•Protein Energy
Malnutrition
•Measles, Chickenpox,
High Fevers
•Bronchopneumonia,
Tuberculosis, Diphtheria
•Gastroenteritis,
Dysentery, Worm
Infestations

36. Xerophthalmia in Nepal:
•Two sources of information
–Tribhuvan University Survey (1980-1981 AD)
–Nepal Blindness Survey (1980-1981 AD)
•Major public health problem
•0.9% bilateral blindness due to nutritional
corneal ulceration
•Every day one child dies and one child goes
blind of xerophthalmia

37. Normal Vitamin A Metabolism
Dietary Vitamin A
(Carotenes in plant food)
(Retinol in animal food)
Digestion and absorption of Vitamin A from the
food Transport in intestinal lymphatics
1. Storage of Vitamin A in liver cells as retinol
2. Production of retinol binding protein (the carrier protein)
Transport of retinol bound to retinol binding protein
1. Formation of rhodopsin - used in night vision
2. Maintenance of healthy corneal and conjunctival cells
FOOD
INTESTINE
LIVER
BLOOD
EYE

38. Vitamin A Deficieny
Dietary deficiency
of Vitamin A
Diarrhoea; Gastroenteritis; Parasites
Not enough Vitamin A
stored in the liver
Low Vitamin A levels in the blood
Night Blindness
FOOD
INTESTINE
LIVER
BLOOD
EYE
Anorexia from
other diseases
Protein Energy
Malnutrition
Poor intestinal absorption
Not enough Retinol
Binding Protein synthesis
Xerophthalmia

39. Slide XE01
Conjunctival xerosis (X1A) and corneal xerosis (X2)
The term conjunctival xerosis (X1A) applies to any stage of
xerotic change in the conjunctiva, with thickening and
wrinkling in advanced cases as in this slide. In this case there
is also infiltration and haziness of the cornea (X2).

40. Bitot’s spot is a single or multiple heaping up of
desquamated keratinised bulbar conjunctival epithelial
cells, most commonly in the inter-palpebral fissure on the
temporal aspect of the eye. Most spots are foamy, some
are more solid and cheese-like. In children under the age
of about 6 years they usually respond to vitamin A dosing.
However, sometimes they are unresponsive and then
probably indicative of VAD in the past. In older children
and adults they are usually unrelated to VAD.

42. •Most of the bulbar conjunctiva is covered
with foamy, keratinised
epithelial cells. The cornea is hazy and
the limbus is infiltrated by fine
blood vessels (neovascularisation).

43. Most of the bulbar conjunctiva is covered with
foamy, keratinised epithelial cells. The cornea is
hazy and the limbus is infiltrated by fine blood
vessels(neovascularisation).

44. Cloudy cornea, corneal
ulcer

45. Keratomalacia is due to severe VAD in which the
cornea liquefies in the acute stage. On resolution
various types of corneal destruction/scarring are
inevitable, as is visual impairment

47. •A case that could be treated.
•An advanced state of deficiency
with keratomalacia.

48. The same eye one month after treatment.
The child was treated immediately with large doses of
vitamin A.
The cornea has healed and there is only a scare left in the
lower part,
not impairing vision. This child was lucky.

49. Scars attributable to VAD are usually bilateral and located in
the central and inferior portion of the cornea. In the field
these inactive lesions are often one of the commonest
clinical pieces of evidence of a public health problem of VAD
in the past. However, a careful history must be taken to
exclude those not related to VAD in the past; they might
result from injury or infectious eye disease.

50. Plate 1: Xerophthalmic fundus in a 24-year-old otherwise
well nourished Indonesian woman who presented with
night blindness, constricted visual fields and severe
conjunctival and corneal xerosis.
Plate 2: Two months after vitamin A therapy the small
yellowish-white retinal lesions in the patient in Plate 1
have largely disappeared

52. Eye Changes
1.Conjunctiva
X1A
X1B
+ XN
1.Cornea
X2
X3A
X3B
XS
1.Retina
XN
XF
Warning Sign
Medical + Ophthalmological
Emergency
First Sign of Xerophthalmia

53. The Recommended Doses of
Vitamin A
•Prophylactic Schedule:
Dose By Mouth
mg I.U.
–All Children 110 200,000
Every 4 -6 months
–Mothers 110 200,000
Just after giving birth
For children less than 1 year of age, reduce dose by one half

54. The Recommended Doses of
Vitamin A
•Treatment Schedule:
If the children is severely ill with gastroenteritis or unable to swallow,
the first dose should be intramuscular injection water soluble
Vitamin A
Emergency
Treatment of
Children with
Xerophthalmia
or Corneal
Ulcers
Day / Week Dose By Mouth
mg I.U.
Day 1 110 200,000
Day 2 110 200,000
Day 14
(2-4 Weeks)
110 200,000

55. National Vitamin A Programme
•Children : 6 months - 5 years (3.5 Million)
•Twice a year : April 18 & 19
October 18 & 19
•Coverage :75 districts - 85%
•FCHV :48,000
•Reduction of Child Mortality : 20-25 thousand

56. Prevention of Xerophthalmia
•Distribution of Massive Dose Capsules
•Fortification of Foods
•Horticulture and Agriculture
•Nutrition and Health Education
i.Late Weaning
ii.Early Supplementation
iii.Mass Media Radio, TV
iv.Changing Eating Habits
•Immunization

57. Treatment of Xerophthalmia
A.MEDICAL
1.Vitamin A Massive Dosing
•Oral: Day 1, 2, 14 - 200,000 I.U.
•Injection: 1
st
Day Only - 100,000 I.U.
Water Miscible
No oily preparation
If not available: Give food rich in Vitamin A
2.Supportive Therapy
•Fluids
•Proteins
•Control of Infection
•Deworming

58. Treatment of Xerophthalmia
A.MEDICAL
3.Eye
•Antibiotcs, Mydiatrics
•Pad specially in X3A, X3B
•Avoid Exposure: Antibiotic Ointment
•Methyl Cellulose Drops
A.SURGERY
1.Conjunctivoplasty
2.Keratoplasty
a.Prophylactic
b.Optical
A.REHABILITATION

59. Prevention of Vitamin A
deficiency
–Breastfeeding
–Vitamin A
supplementation
–Food fortification
–Promotion of
vitamin A-rich diets

60. T
H
A
N
K

Y
O
U
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