Download Drugs causing Amblyopia

Drugs causing Amblyopia
Ethambutol
Uses
Toxic dose
Symptoms
Onset
Treatment of
TB along with
INH,
Rifampicin
25 mg/kg/d
Toxicity is
dose related
Sudden
Within 3-6
months of
starting
treatment
Laterality
VA
Color
Signs
ONH
Optic nerve
Amiodarone
Vigabatrin
Antiarrhythmic
Anti-epileptic
Not dose
related
Idiosyncrasy
NOT dose
related
Insidious
Uni- or Bi-
Blue-yellow
"central"
Red-green
"peripheral"
Normal or
slightly
swollen
Splinter
hemorrhage
Swelling
persists after
cessation of
drug
Fundus
Visual field
After months or
years of starting
treatment
Nasal (inverse)
atrophy
Normal or
peripheral
atrophy,
abnormal
macular reflex
Central,
centrocecal
OR
Mild &
reversible OR
severe &
Bilateral
concentric OR
bi-nasal, persists
Topiramate
Anticonvulsant
Treat
migraine
Acute ACG
with
associated
myopia 2ry
to ciliochoroidal
effusion
Shallow AC
↑ IOP
Starting
within 1
month of
treatment
Anti-malarial
»
»
SLE
RA
- Chloroquine: ≥250 mg/d, ≥3
years
- Hydroxy-chloroquine: ≥6.5
mg/kg, ≥5 years
 Pre- maculopathy:
1. Normal VA
2. Scotoma to red target 4̊ - 9̊
from fixation
3. Detected by Amsler grid,
Hardy Rand Rittler test
4. Reversible if drug is
stopped
 Early maculopathy:
1. Mild ↓ VA  6/9 – 6/12
2. Subtle Bull's eye macula
3. FFA  window defect
4. May progress even if the
drug is stopped
 Moderate maculopathy:
1. VA  6/18 – 6/24
2. Obvious Bull's eye macula
 Severe maculopathy:
1. VA  6/36 – 6/60
2. Widespread RPE atrophy
 End stage maculopathy:
1. Marked ↓↓↓ VA
2. Marked RPE atrophy
3. Attenuated retinal
arterioles
Macula
Phenothiazines
Crystlline
maculopathy
Anti-psychotic
- Tamoxifen:
"Schizophrenia" » cancer
breast
» antiestrogen
- Thioridazine:
» Toxic >40
≥800 mg/d
mg/d
Chlorpromazine
- Canthaxanthin:
» Carotenoid
» Enhance sun
tanning
Other drugs
- Interferon:
See below
- Nicotinic acid:
» Cholesterol
lowering
agent
» Toxic dose >
1.5 g/d
» CMO
» Mild ↓ VA
- Methoxy- Salt & pepper
flurane:
- Desretinopathy
»
GA
ferroxamine:
- plaque like
pigmentation & » Metabolized » Iron chelating
to oxalic acic
agent used in
RPE atrophy
which
binds
patients on
- Diffuse RPE &
to Ca 
regular blood
chorio-capillaris
insoluble
transfusion
atrophy
salts
» Rapid ↓ VA
» Pigmentary
- Nitroretinopathy
furantoin:
» FFA 
» Antibiotic
mottled
» Treatment
hyperof UTI
flourescence
Peripheral
constriction
permanent
after cessation
of drug
Treatment
Prognosis
Screening
Characteristics
Good
following
cessation of
ethambutol
Every 4 weeks
Sudden
Splinter
Central or
peripheral
Dose 25 mg
Stop the
drug
Aqueous
suppressants
Good
Variable
Not
appropriate
Baseline VF,
every 6 months
Acute ACG
Myopia
OR
» Amsler grid  weakly
» VA  annualy
Bull's eye macula