Part 1 Flashcards
Outer membrane of eye
Anterior most 1/5th cornea
White 4/5th sclera
Covered w bulbar cunjuctiva with sclera beneath
What is limbus
Junction of cornea and sclera
Pupil size? Function
2-4mm
Dilate- mydriasis
Contract- miosis
Miosis by?
Sphincter pupilae muscle constriction
Mydriasis by?
Dilator pupilae muscle
Sphincter pupilae muscle innervated by which nerve?
Oculomotor nerve CN3
Dilator pupilae innervated bywhich nerve?
Sympathetic nerves
Heterochromia iridum
Different colour of Iris in different eyes
One eye brown one eye blue
Heterochromia iridis
Different colour in same eye
Patient comes with partial ptosis, miosis, enophthalmos of one eye and anhydrosis on one side of face. There’s loss of cilliospinal reflex
What is Dx?
Horner’s syndrome
Horners syndrome
Piece MEAL
P- partial ptosis
M - miosis
E - enophthalmos
A - anhydrosis
L - loss of cilliospinal reflex
Occurs due to compression of cervical sympathetic chain.
Partial ptosis caused by Muller’s muscle palsy which is innervated by sympathetic nerve
Miosis caused due to palsy of dilator pupilae muscle nerve, also sympathetic.
Ptosis caused by which nerve palsy?
Lavator palpebra superioris
Which lung tumour leads to Horner syndrome?
Pancoast tumour
Superior sulcus tumour of the lung causing compression of the cervical sympathetic chain
Eye components
Outer fibrous layer- cornea and sclera
Middle layer is vascular - Iris, ciliary body and choroid
Inner layer is neural- retina
Thinnest, anterior most part of retina
Orra serrata
Ciliary body components
Pars plana
Pars plicata- responsible for aqueous humour production.
Volume of orbit
30ml
Volume of eyeball
7ml
Volume of posterior segment
4ml
Posterior segment is filled by vitreous humour
(Portion posterior to the lens)
Volume of anterior chamber and posterior chamber
0.25ml AC
0.06ml PC
Anterior segment is divided into anterior and posterior chambers.
Eye development starts by which week of gestation?
3rd week of intrauterine life
(21 days)
Neuroectoderm derivatives
VOIR
V- secondary virtuous
O- optic nerve
I - iris
R - retina
Neural crest sells derivatives
** C3OST**
C- cornea
C- ciliary ganglion
C- ciliary muscles
O- optic nerve sheath
S- sclera (partly made from mesoderm)
T- trebacular meshwork (drainage of AH)
Normal Axial length?
Newborn- 16.5mm
Adult- 24mm
Normal Corneal size?
Newborn- 9mm
Adult- 11mm
Takes 2 years to reach adult size
Newborn eye is hypermetropic by how much?
+2 to +3 diopters
Lens derives it’s nourishment from?
Aqueous humour, more than vitreous humour
Refractive power of eye?
+60 diopters
Corneal- +43D
Lens- +17D
Refractive Indices
Refractive Index of-
Aqueous = Vitreous = 1.34
Cornea- 1.37
Lens- 1.39
Center of Lens- 1.42 (max)
Lens capsule is made up of?
Type 4 collagen
Type 4 collagen also present in?
Basement membrane
Lens capsule is thinnest at?
Posterior pole
Coloboma
Congenital anomaly caused by Inability of hyaloid fissure to close (closes by 7-8 wk of IUL)
Most common type- infronasal
(Pupil dripping down. See picture)
Anterior lenticonus
Hereditary condition
Anterior conical protrusion of lens
Seen in Alport syndrome
Triad-
Can’t hear (SNHL)
Can’t see (AL)
Can’t pee (nephritic syn)
Most common cause of cataract
Old-age
senility
Most important drugs that cause cataract
Steroids
Most common cause of blindness
First- cataract
Second- refractive error
Most dangerous type of cataract
Posterior polar cataract
Characteristic onion peel appearance of opacification of lens
What type of cataract is seen in diabetes mellitus?
Snowflake cataract
More common in type 1 than type 2.
Due to accumulation of sorbitol, made by conversion of glucose by aldose reductase enzyme
Cataract due to deposition of copper in lens?
Sunflower cataract
Seen in Wilsons disease and chalcosis
Copper deposition causing brown ring formation around cornea?
kayser Fleischer Ring or kf ring
In copper excess conditions
(Wilson’s disease and chalcosis)
Cu deposition in the descemets membrane of cornea.
Which type of cataract seen in galactosaemia?
Oil drop cataract
due to accumulation of galactitol/ dulcitol
Caused by conversion of galactose by aldose reductase enzyme
Only reversible cataract?
Oil drop cataract
Blunt trauma causes, which type of cataract?
Rosette cataract
Rose petal like pattern
Most common type of complicated cataract
Posterior subcapsular cataract
Stages of cataract
1- Incipient cataract
2- Immature cataract
3- Intumescent cataract
4- Mature cataract
5- Hypermature cataract
o Calcified
o Morgagnian
Complication of morgagnian cataract
Phacolytic glaucoma
Complication of sclerotic/calcified cataract
Phacotopic glaucoma
Features of hypermature/morgagnian cataract
Bag of milk appearance, due to cortex liquefication
and sunken nucleus
Patient with
Gradual painless loss of vision
Glare
Coloured halos
Second sight
Dx?
Cataract
Second sight means near vision is getting better, seen mc in nuclear cataract
Senile cataract
Rx of cataract
1st line- phacoemulsification
Incision is 3.2mm
1- keratome used to make incision in SICS( small incision cataract surgery)
2 ant. chamber is maintained by hydroxypolymethylcellulose
3 capsuporrhexis
4 hydrodissection
5 sculpting of nucleus
6 cracking of nucleus
7 emulsification of each quadrants
8 cortical cleanup and insertion of IOL
Cataract surgery also done bye other procedure?
FLCS
femtolaser assisted cataract surgery
Is a type of Nd Glass laser
Wavelength of 1053nm
Complications of cataract surgery
UGH syndrome:
Uveitis
Glaucoma
Hyphaema (blood in ant chamber
Early complications of anterior chamber IOL insertion
Intraocular lens
Rigid- poly methylmethacrylate
Foldable- best- acrylic.
Ideal site - posterior chamber
(In the bag)
Endophthalmitis
Dx
Rx
Inflammation of vascular and retinal layer of eye
Can be early or late
Early: staph epidermididis
Late: propionibacterium acne
red sclera
Hazy cornea
Hypopyom- pus in ant chamber
Sudden pain full loss of vision
early complication of cataract surgery
Rx- intravitreal inj. of antibiotics
Late complication of cataract surgery
Posterior capsular pacification PCO
/Secondary cataract
Can be of 2 types
1- elschnig’s pearls. More common (children) pearly opacities
2- sommering rings
Patient will present after 6 to 8 months of cataract surgery with Gradual painless loss of vision
Rx- Nd yag laser capsulotomy (opening)
Nd Yag laser
neodymium-doped yttrium aluminium garnet
Wavelength: 1064 nm
Common in posterior capsular opacities (capsulotomy)
Subluxation
MCC- marfans syndrome- fibrillin 1 gene mutation
MC type- Superotemporal subluxation
Inferonasal subluxation- caused by homocystinuria
Congenital cataract
- abnormal white pupillary reflex= leucokoria
-mc type- blue dot 🔵 cataract (universal)
- vision is perfectly normal.
- zonular cataract (opacification of zonules) / lamellar cataract.
- can lead to blindness
Raccoon eyes
Bilateral ecchymosis
Due to anterior cranial fossa fracture
Vossius’ Ring
Pigmented ring like shape formed by iris coming into contact w cornea due to a concussion injury and leaving some pigment behind
Orbital Fracture
Most common- floor of orbit fracture
With characteristic tear drop sign.
Weakest wall- medial wall of orbit
Palsy-
1- infraorbital nerve
2- inferior rectus muscle
D shaped pupil
Iridodialysis
Separation of iris form it’s base
Pt. Complains
Redness
Watering
Discharge
Conjunctivitis
Most common type of conjunctivitis?
Viral
adenovirus
Most common bacteria, causing conjunctivitis?
Staphylococcus aureus
Angular conjunctivitis MCC
MCC- morexella axenfeld
Temporal side of the conjunctiva/lateral canthus maceration
Subconjunctival haemorrhage
PACE
Haemorrhagic conjunctivitis, more commonly seen in viral
P- picorna virus
A- adenovirus
C- coxsakie
E- entero virus/ echo
MCC- Accu haemorrhagic conjunctivitis- Apollo virus.
Trachoma
-Chronic inflammation of cornea and conjunctiva
Corneal opacity- pannus
-Also known as- Egyptian ophthalmia
- cause- clamydia trachomatus (a- c serotypes)
- SAFE strategy
Surgery
Antibiotics
Facial cleanliness
Environmental sanitation
- DOC- azithromycin
- prophylactic- 1% tetracycline ointment
Trachoma features
-Follicles give sago grain appearance
-Papillae give velvety appearance
-Arlt’s line - conjunctival scarring in the upper lid
-Herber’t pits- depresses scar follicles on the upper limbus (pathognomic feature)
HAPPy For Trachoma
Opthalmia neonatorum
-Infection in first 28 days of life
-MCC- clamydia trachomatis(D to K)
-Most severe- gonococcal (1-3 days)
Hsv if after a week
Vernal keratocunjunctivitis VKC
Also called spring cataract
Type 1 hypersensitivity to exogenous allergens
More common in young boys
Olopatadine -DOC
- HORNER TRANTA SPOTS eosinophilic accumulation at the upper limbus
- cobblestone pppilae over the palpebral conjunctiva.
-
shield ulcer
-Thick ropey discharge maxwell Lyon sign - pseudo garantoxon
Rx-
Preventive - Avoid allergens, Dry hot climate, rubbing eyes,
Lid hygiene, sun glasses, cold compression.
Antihistmamines (Topical/Oral)
Mast cell stabilisers
NSAIDs - Ketotifen
Topical or Oral Steroids
Acetylcysteine drops
Topical Cyclosporin
Supratarsal injection of steroids
Arcus senilis/ gerontoxon
Arch like deposition of lipids in corneal periphery
Phlyctenular conjunctivitis
-Type 4 hypersensitivity reaction
-By endogenous allergens
-Most common- staph aureus + tuberculin protein
Common in tb
Pterygium
- Wing shaped flap of conjunctiva seen encroaching the cornea
- cause- UV B Rays causing elasticity degeneration
- more common on nasal side
- surgery indications- cosmesis (don’t look nice)
- stocker’s line (iron deposits)
- Types: progressive, regressive, stationary.
Ptregium rx
- Tear substitute
- Topical steroids
- Sunglasses and then simple/conjunctival flap excision
- Bare sclera/conjunctival autograft/flap surgery for excision
To prevent recurrence after excision all of the following Conjunctival autograft:
6. Amniotic membrane transplantation
7. Mitomycin C with excision to prevent recurrence
8. Radiation
9. Argon Laser
10. Peripheral lamellar keratoplaty.
Bitot spots
White frothy toothpaste like spots on sclera
Feature of - xerophthalmia
vit. A deficiency
First feature- night blindness
First sign- conjunctival dryness
(X1a- conjunctival xerosis
X1b- bitot spots
X2- corneal xerosis
X3a- corneal ulceration
X3b- keratomalacia
XN- night blindness
XF- xerophthalmia fundus)
Thickest layer of cornea
Stroma
Normal cell count of endothelium layer of cornea
2500 cells/cubic meter
Checked by specular microscope
Fall below 500 leads to corneal opacity
Corneal ulcer
MCC- bacterial
Signs-
hazy cornea
Hypopyon- mobile and sterile
Most common corneal dystrophy
Epithelial
Most common stromal corneal dystrophy
Lettice
Interstitial keratitis
Involves the stroma of cornea
Feature of congenital syphilis
Hutchinsons triad-
Hutchinson teeth
Interstitial keratitis
Sensorineural hearing loss
