06/27/2017

Ophthalmology mci screeningt test and indian medical examz high yield important topics study METHOD

By Live Dr - Wed Feb 11, 2:51 am

Ophthalmology

Layers of cornea
Epithelium- stratified squamous epithelium

Bowman’s membrane- condensed collagen fibrils

Stroma / substantia propria – collagen fibrils

Descemete’s membrane/ posterior elastic lamina

Endothelium – single layer

*Refractory index of emmetropic eye= 60 D

Normal intraocular pressure is 10-22 mm of Hg

AVASCULAR OCULAR STRUCTURES
Vitreous

Cornea

Lens.

Protanopia Defective red colour perception
Deuteranopia Defective green colour perception
Tritanopia Defective blue colour perception
sudden painless loss of vision
Central retinal artery occlusion

Vitreous hemorrhage

Retinal detachment

Central retinal vein occlusion

Central serous retinopathy

Optic neuritis

gradual painless loss of vision
Pterygium encroaching on papillary area

Corneal degeneration

Corneal dystrophies

Senile cataract

Optic atrophy

Diabetic retinopathy

Refractive errors

QUOTE CORNER

You may be disappointed if you fail, but you are doomed if you don’t try- Beverly Sills

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                105

sudden painful loss of vision
Acute congestive glaucoma

Acute iridocyclitis

Injuries

gradual painful loss of vision
Chronic iridocyclitis

Corneal ulceration

Chronic simple glaucoma

transient loss of vision

amaurosis fugax

Migraine

Carotid artery disease

Raynaud’s disease

CAUSES OF night blindness
Vitamin A deficiency

Retinitis pigmentosa

Myopia

Peripheral cortical cataract

Oguchi disease

Goldmann Favre disease

Myopia

CAUSES OF hamarlopia (day blindness)
Central nuclear cataract

Central corneal opacities

Central vitreous opacities

CAUSES OF Leucocoria
Retinoblastoma

Congenital cataract

Coloboma choroids

Retinopathy of prematurity

Persistent hyperplastic primary vitreous

Toxocara endophthalmitis

Coats disease

TRIVIAL TRUTH

The farthest you can see with the naked eye is 2.4 million light years away! (140,000,000,000,000,000,000 miles.) That’s the distance to the giant Andromeda Galaxy. You can see it easily as a dim, large gray “cloud” almost directly overhead in a clear night sky.

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                106

CAUSES OF Cloudy cornea at birth
Glaucoma

Trauma

Intrauterine infections

Mucopolysaccharidoses

Mucolipidosis

causes of cherry red spot In macula ARE
crao

Tay sach’s disease

Niemann pick’s disease

Gaucher’s disease

Sandhoff’s disease

Sialidosis

CAUSES OF Neurotrophic keratopathy
Herpes zoster

Herpes simplex

5th nerve damage

Diabetes

Leprosy

Causes of tunnel vision
Glaucoma

Retinitis pigmentosa

High myopia

High powered glasses

Crao with sparing of cilioretinal artery

Leutic chorioretinitis.

Iridocyclitis

Keratic precipitates- Proteinaceous cellular deposits at the back of cornea

Mutton fat kp Occur in granulomatous iridocyclitis, composed of epithelioid cells and macrophages.

Large, thick and fluffy.

Granular kp Small and medium, of non granulomatous origin, composed of lymphocytes.
Red kp Along with lymphocytes, erythrocytes also take part in composition, seen in hemorrhagic uveitis
Old kp Healed uveitis-shrunken, lightly pigmented and crenated

QUOTE CORNER

Try not to become a man of success but rather to become a man of value-Albert Einstein

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                107

Organisms penetrating intact cornea
N. gonorrhea

N. meningitides

C. diphtheriae

Acanthamoeba

Listeria monocytogenes

Images in ophthalmoscopy

direct ophthalmoscopy indirect ophthalmoscopy
Erect Inverted
Virtual Real
15 times magnification 5 times magnification
Can visualize slightly beyond equator Can visualize upto ora serrata
Not useful in hazy media Helpful, as illumination is bright
Stereopsis absent Present
Done at a distance of 15mm from eye Done at an arm’s length’s distance from eye
Adie’s pupil Due to degeneration of ciliary ganglion

Dilated pupil

Tonic reaction to light and accommodation

Associated with hyporeflexia (Holmes-Adie pupil)

Marcus-Gunn pupil Normal sized pupil

Relative afferent papillary defect

Cause optic nerve / retinal disease.

JAW WINKING OF MARCUS GUNN
Due to aberrant regeneration of nerve fibres. Spasm of one levator palpebrae occurs on movement of jaw.

Seen in congenital Ptosis.

Order of loss of visual field in Glaucoma

First Isopter contraction
Second Baring of blind spot
Third Wing shaped paracentral   scotoma (first clinically significant)
Second last Loss of temporal island
Last Macular fibres lost.
Epidemic dropsy glaucoma /Bengal glaucoma
Characterized by diarrhea, edema legs, myocarditis

Visual field changes resemble those of chronic simple glaucoma

TRIVIAL TRUTH

If we put together all the time we spend blinking, we would see blackness for 1.2 years.

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                108

SPECIAL TYPES OF CATARACT

CATARACT MORPHOLOGY/ NAMES CAUSE
Christmas tree Myotonic dystrophy
Sunflower Wilson’s disease
Rosette Concussion trauma
Oil drop Galactosemia
Snowflake / snowstorm Diabetes mellitus.
Polychromatic luster Complicated cataract
Blue dot Cortical developmental cataract
Glassblower’s Infrared radiation.
Anterior subcapsular Anti-cholinesterase
Posterior subcapsular Radiation / steroids
Shield cataract Atopic dermatitis
Spoke like cataract Mannosidoses
Propeller cataract Fabry’s disease
Stages of maturation of cortical senile cataract
Stage of lamellar separation by fluid

Stage of incipient cataract

Immature senile cataract

Mature senile cataract

Hypermature senile cataract

*Second sight

In nuclear cataract, refractive index of lens increases so the light rays become more convergent and patient becomes more myopic

So his near vision   improves and presbyopia is corrected.

Trachoma

Caused by Chlamydia trachomatis serotypes A, B, Ba, and C, D and K

The organism produces intracytoplasmic inclusion bodies called H.P. bodies (Halberstaedter Prowazeke bodies)

Arlt’s line- linear scars present in sulcus subtarsalis

Herbert follicles- typical follicles present in the limbal area

Herbert pits – circular pitted scars left after healing of Herbert follicles

Diagnostic Criteria  FOR Trachoma ( At least 2 of following)
Follicles on upper tarsal conjunctiva

Limbal follicles or Herbert’s pits

Typical conjunctival scarring

Vascular pannus most marked in the superior limbus

QUOTE CORNER

The future belongs to those who believe in the beauty of their dreams. Eleanor Roosevelt

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                109

WHO Classification (1987)

Meant to be used by field workers.

TF Trachomatous Inflammation Follicular > 5 follicles (> 0.5 mm diameter) on upper tarsal conjunctiva
TI Trachomatous Inflammation Intense Inflammation & papillary hypertrophy obscuring > ½ of tarsal vessels
TT Trachomatous Trichiasis At least 1 trichiatic cilia rubbing on the globe or evidence of its recent removal
TS Trachomatous Scarring Obvious trachomatous scarring of upper tarsal conjunctiva
CO Corneal Opacity Trachomatous corneal opacity at least a part of which extends over the pupil

Mac Callan’s classification of trachoma based on conjunctival characteristics

Stage 1

Incipient trachoma

Immature follicles on superior palpebral conjunctiva
Stage 2

Established trachoma

Mature follicles on superior palpebral conjunctiva
Stage 3 Cicatrizing trachoma

Follicles, scarring or superior tarsus

Stage 4 Healed trachoma

No follicles, extensive conjunctival scarring.

Sequelae Trachoma
Distortion of lids

Entropion

Trichiasis

Ectropion (hypertrophy of conjunctiva)

Herbert’s pits

Ptosis (tylosis & infiltration of LPS)

Madarosis

Posterior symblepharon

Parenchymatous xerosis

Defective lid closure, lid deformity & deficient tear film corneal damage.

Cicatrization involving lacrimal drainage & dacryolith formation epiphora

Glaucoma (perilimbal fibrosis & infiltration of the outflow channels)

Secondary Infection

H. aegypticus (commonest)

TRIVIAL TRUTH

After spending hours working at a computer display, look at a blank piece of white paper. It will probably appear pink.

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                110

Laws of ocular motility

Herring’s law Yoke antagonist muscles and yoke antagonist muscles receive equal innervation
Sherrington’s law of reciprocal innervation Increased innervation of contacting agonist muscle is accompanied by simultaneous decreased innervation of its antagonist.

Hirschberg test

Used to roughly estimate the angle of deviation in strabismus

Edge of pupil

15degree

Mid cornea

30 degree

Corneal margin

45 degree

Sclera

60 degree

1mm from papillary centre

7 degree

Nasal limbus

-35 degree

The plan followed in the management of squint  (in order)
Refraction

Orthoptic exercise

Operative correction

Prism for remaining error after operation

GRADING OF HYPERTENSIVE RETINOPATHY

Grade 1 Mild generalized arteriolar attenuation.
Grade 2 Grading of hypertensive retinopathy-

Marked generalized narrowing and focal attenuation of arterioles, with deflection of veins at the arteriovenous junction

Grade3 Grade 2 plus copper wiring of arterioles,

Banking of veins, distal to a-v crossing

Flame shaped hemorrhages , cotton wool spots and hard exudates

Grade 4 Grade 3 plus silver wiring of arterioles and papilloedema

Signs of hypertensive retinopathy

Salu’s sign Arteriovenous nipping
Bonnet’s sign Dilated vein distal to a-v crossing
Gunn’s sign Tapering of vein on either side of crossing

Right angle deflection of vein

Elschnig’s spots- Ischemic Choroidal infarcts

QUOTE CORNER

There are no failures – just experiences and your reactions to them.- Tom Krause

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                111

Retinoblastoma

Treatment

Small tumors Photocoagulation

Transpupillary thermotherapy with laser or cryotherapy

Medium tumors Brachytherapy

External beam radiotherapy with cobalt

Chemotherapy

Large tumors Enucleation

Chemoreduction

*Enucleation is most widely practiced modality of treatment in unilateral sporadic disease and in the more affected eye in bilateral disease.

Most cases of familial retinoblastoma are bilateral.

*Most common presenting feature of retinoblastoma is Leucocoria

*Trilateral retinoblastoma-

Bilateral retinoblastoma with midline intracranial tumour.

*Amaurotic cat’s eye reflex- yellowish white, nonreacting, pupil in retinoblastoma and pseudoglioma

*Rhabdomyosarcoma is the most common primary orbital malignant tumour and most common soft tissue tumour malignancy in children

Foster Kennedy syndrome
Tumour of anterior cranial fossa

Ipsilateral papilloedema

Contralateral optic atrophy

Ectopia lentis

Marfan’s syndrome Most common cause of inheritable EL

Bilateral Upward and temporal displacement

Homocystinuria Second most common cause

Downward nasal displacement

Weil-Marchesani syndrome Forward displacement
Other conditions CAUSING ECTOPIA LENTIS
Sulfite oxidase deficiency

Hyperlysinemia

Ehlers Danlos syndrome

Refsum’s disease

Sturge-Weber syndrome

Pierre-Robinson syndrome

TRIVIAL TRUTH

When a person dies, hearing is generally the last sense to go. The first sense lost is usually sight. Then follows taste, smell, and touch.

ELEVENTH HOUR OPHTHALMOLOGY                                                                                               112

Horner’s syndrome
Ptosis

Miosis

Enophthalmos.

Anhydrosis

Loss of cilio spinal reflex.

RETINAL CHANGES IN SICKLE CELL DISEASE
Sea fan neovascularisation

Black sun bursts

Salmon patch haemorrhage

Angioid streaks.

*Vision 2020

Global initiative by who, to eliminate avoidable blindness by 2020

Economic blindness Vision less than 6/60
Social blindness inability to move around

Vision less than 3/60

laser used in
nd-yag after cataract
excimer laser LASIK, keratotomy,
frequency doubled nd-yag, argon-green, diode, krypton retinal photocoagulation
PRE-REQUISITES FOR LASIK

(Laser assisted in situ keratomileusis)

Age should be more than 21 years

Stable refractory error

Corneal thinning disorder should be ruled out

It can correct myopia of range -6 to -30 diopters.

Refsum’s syndrome
Retinitis pigmentosa

Peripheral neuropathy

Cerebellar ataxia

Tropicamide Shortest and quickest acting
Phenylephrine Only mydriatic
Cyclopentolate Only cycloplegic

QUOTE CORNER

Consider calling it a challenge rather than calling it a crisis.- Mary Anne Radmacher

ELEVENTH HOUR OPHTHALMOLOGY                                                                                              113

STAPHYLOMA

Anterior Ectasia of pseudocornea
Intercalary Localized bulge in limbal area lined by iris root
Ciliary 2-3 mm away from limbus, lined by ciliary body
Equatorial Choroidal incarceration at the equator
Posterior Lined by choroids behind the equator
Chalazion Chronic inflammation Meibomian gland
Hordeolum externum Suppurative inflammation of glands of Zeiss
Hordeolum internum Suppurative inflammation of Meibomian glands
Vernal keratoconjunctivitis / Spring catarrh
Recurrent bilateral external ocular inflammation seasonal-spring

Cobblestone / pavement stone -hard flat topped papillae in upper tarsal conjunctiva and Tranta’s spots-discrete whitish raised dots along the limbus.

Episcleritis periodica fugax Frequent attacks of episcleritis due to allergic reaction to internal toxin

Commoner in women

Associated with rheumatoid arthritis

Ophthalmia nodosa Caterpillar hair conjunctivitis

Granulomatous inflammation of conjunctiva, leading to formation of nodule on the bullbat conjunctiva in response to irritation caused by the retained hair of caterpillar

Pinguecula Yellowish white patch on the bulbar conjunctiva near the limbus
Pterygium folds of conjunctiva encroaching upon the cornea.
Acanthamoeba infection
Contact lens wearers who use distilled water and salt tablets instead of commercial saline solution

Corneal scrapings are stained with calcoflour white dye / potassium hydroxide mount / lactophenol cotton blue

Treated with polymethylene biguanide or chlorhexididne with propamidine

25 % Na fluorescin fundus fluorescin angiography
2 % Na fluorescin Staining corneal ulcers.

TRIVIAL TRUTH

It’s speculated that Vincent Van Gogh’s affection for yellow colouring in his paintings, could be due to xanthopsia, which is a symptom of digitalis toxicity which was used in his days for epilepsy, from which he suffered.

It may also be due to a neurotoxin called thujone found in a type of liquor absinthe, of which he was fond.

ELEVENTH HOUR OPHTHALMOLOGY                                                                                               114

*CMV retinitis is the most common form of chorioretinitis

cmv retinitis is seen when CD4+ count < 50

*Commotio retinae (Berlin edema)

Due to concussion injury on eye

Milky white cloudiness due to edema appears over posterior pole

*Distichiasis

Partial or complete row second row of eye lashes

Candle wax spots Retinopathy of sarcoidosis
Salt and pepper fundus Congenital syphilis
Watered silk appearance of fundus Hypermetropia

*Snow blindness

Temporary loss of vision and inflammation of the conjunctiva and cornea caused by exposure of eyes to bright sunlight and ultraviolet rays reflected from snow or ice

8Hippus

Rhythmic papillary constriction and dilation

Sign of multiple sclerosis / aconite poisoning.

*Mustard gas (yellow cross) causes orange skin cornea.

*Hutchinson’s sign-

In herpes zoster when vesicles are present on the sides and tip of nose, cornea may be involved.

QUOTE CORNER

Obstacles are things, a person sees when he takes his eyes off his goal.- E. Joseph Cossman

ELEVENTH HOUR OPHTHALMOLOGY                                                                                                115

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