Showing posts with label Ophthalmology. Show all posts
Showing posts with label Ophthalmology. Show all posts

Wednesday, August 29, 2018

Movements of eye muscles.

This post is actually the primary post for squint studies. Just basic post so we can explore squint in easy and simplified manner.
So there are seprate diagrams for anatomical and clinical functions. In this post we will go for former part.
Anatomical functions diagram.

Note: Don't use this diagram when you are studying squint. This diagram is used only for movements of eye muscles.
So every muscle has 3 actions except medial and lateral rectus.
Actions are divided into three types Primary, secondary and tertiary.
We know the basic or primary action of superior and inferior rectus is to elevate and depress the eyeball respectively.
According to the diagram given you also know that superior rectus can intort and adduct. Similarly, inferior rectus can extort and adduct the muscles.

How to remember this?
1) Through diagram.
2) Trick: Recti muscles are adductors

Now comes to SO(Superior oblique) and IO(Inferior oblique). Now this is also basic which we fail to notice often. These muscles are coming to tarsus part of eye obliquely. So, primary action is intortion and extortion respectively. Now go to diagram and you will notice that IO actually corresponds to SR hence it performs elevation and SO corresponds to IR so it performs depression.
Also, both the muscles are "Abductors"

How to remember this?
1) Diagram off course!
2) Trick: Superior muscles are Intorters and inferior muscles are extorters.
To keep the things in apple pie order I have made this chart. Hope it helps.
-Demotional bloke

Monday, April 30, 2018

Conjunctival xerosis mnemonics

Conjunctival Xerosis

Hello everyone today let's discuss the causes and treatment of conjunctival xerosis.

So basically there are two types of conjunctival xerosis.
a. Epithelial xerosis
b. Parenchymatous xerosis

Epithelial xerosis.
The most common example is Xerophthalmia i.e. Vitamin A deficiency.

Let us discuss Xerophthalmia.

The cause of vitamin A deficiency is mostly its dietary deficiency or defective absorption.

The new WHO classification of Xerophthalmia

XN:   Night Blindness
X1A: conjunctival xerosis
X1B: bitots spots
X2:   corneal xerosis
X3A: keratomalacia <1/3rd of cornea
X3B: keratomalacia >1/3rd of cornea   
XS: corneal scar
XF: fundal changes – known as Uyemura spots, these are defects in the Retinal
Pigment Epithelium.

It consists of local ocular therapy with artificial tears along with vitamin A therapy.
Schedule for vitamin A is as follows :

>1 year of age – 1lakh IU i.m. given on 0 1 14 days
 2lakh IU orally given on 0 1 14 days

<1 year of age – half the dose.

This has to be carried along with treatment of underlying causes like malnutrition or other disorders like diarrhoea dehydration.

Other causes of night blindness:
1. High myopia
2. Late stage of angle closure glaucoma
3. Oguchi syndrome
4. Gyrate atrophy of choroid
5. Retinitis pigmentosa

Parenchymatous Xerosis
It mainly involves the adenoid layer of the conjunctiva.
It can take place due two main reasons     holla! We have a mnemonic here
1. Due to cicatrizing disorders  (cicatrizing disorders turn conjunctiva reasonably shrivelled)
2. Due to over exposure to atmosphere ( marked exposure causes parenchymatous xerosis)

Cicatrizing disorders
1. Cicatricial phemphigoid
2. Diptheric membranous conjunctivitis
3. Trachoma
4. Chemical burns
5. Radiotherapy
6. Stevens-johnson syndrome

Overexposure to atmosphere
1. Marked proptosis
2. Ectropion
3. Coma (lack of blinking)
4. Palsy of cranial nerve 7 (facial palsy)

That’s all for now,
Stay Awesome!
Keep calm and keep studying!

- Ashish G. Gokhale

Wednesday, March 14, 2018

Pursuing ophthalmology in India

Since my mom first introduced me to the slit lamp view of the eye and dad to the indirect ophthalmoscopy, I developed a liking for ophthalmology. The magnified view of the eye through the slit lamp just looks 'oh so beautiful' and it's such a fun challenge to master indirect ophthalmoscopy- I didn't think much in the counselling room while 'locking' the MS Oph option. Also, the fact that you have to work with all the cool gadgets and gizmos, lasers and stuff made me incline towards it.

Ophthalmology is a mutifaceted branch. Those who are into diagnostics and literature get their own share as well as those who want to take matters into their own hands and like to cut,paste, and remove things. The puzzle of diagnosis and the thrill of surgery, both can be had here.

Though not as demanding as general medicine or surgery, ophthalmic surgeries like cataract have a steep learning curve,a personal opinion of mine. But when you make sure that all the things fall into places rightly, it is highly satisfying an experience. The patient's smile the next day when they see clearly feels so good to the heart.

Experience in residency varies per college. I for one am happy with mine. I have done a few basic surgeries like pterygium and dacryocystectomy independently but under supervision during my  first year itself. Currently, I'm working on tunnel making in cataract surgery.
I have seen a lot of interesting cases of lids, cornea, and the fundus.
At times though, performing sac syringing of every pre op patient and filling up of discharge cards of the post op patients makes me go meh. But this is just nitpicking, I have a fair idea about the extreme workload of redundant stuff in other colleges.

After passing out, there are many fellowship programs offered by institutions. Getting a fellowship done is sort of a norm nowdays.

As mentioned before, this is an investment intensive branch, one needs to continually upgrade their machines and bring in new ones
if interested in establishing a privately owned set up. A job in an institution can be an option but things may get pushy or so I've heard.

Summing it up, this is like a cute little baby who is rather tough to please, but when you get it right, the smile is priceless.

Friday, December 29, 2017

Ocular Therapeutics (DYES)

Hello Awesomites! :D

Today I will discuss here


-This dye stain damaged corneal epithelium bright green best seen under cobalt blue and ultraviolet light.
1. To detect breach in continuity of corneal epithelium.
2. Contact lens fitting.
3. Applanation tonometer.
4. Test for leaking wound (Seidel test)
5. Patency of nasolacrimal duct.
6. Fluorescein angiography.
7. Diagnosis of lacrimal fistula.
8. Treatment of pediculosis (Fluorescein dye strips, which are used in the diagnosis of corneal abrasions, may be used in combination with white petrolatum. The strips are applied to the eyelashes for 3 nights)
9. Differential stain along with Rose bengal.

Pattern of stain:-
- interpalpebral staining of cornea & conjuctiva is common in aqueous tear deficiency
-superior Conjuctival Staining in superior limbic keratoconjuctivitis
-Inferior corneal &conjuctival staining in blepheritis & exposure keratitis.

-Stain the devitalized corneal and conjuctival epithelium. The drawback with rose bengal is it stings.
-Seen under white light /red free light. (Red-free light is absorbed by the RPE, creating increased contrast)

1. CORNEA -Staining corneal ulcer,erosion and abrasion.
2. LID- Meibomian gland dysfunction.
3. CONJUCTIVA- Conjuctival staining and evaluation of ocular surface disorder.

I hope it helped.
More is coming up in this section.

-Upasana Y. :)

Friday, November 3, 2017

Sequels of corneal ulcer perforation

Sequels of corneal ulcer perforation :

S- Subluxation of lens
I -  Iris prolapse
L-  Leucoma
I -  Intraocular haemorrhage
C- Corneal fistula
A-  Adherent Leucoma

P- Phthisis bulbi
A- Anterior synechiae
P- Purulent infection
A- Anterior Staphyloma

Thank you :)

~Pratheek Prabhu

Complications of corneal ulcer

Complications of corneal ulcer - "DEPICT"

D- Descemetocele
E- Ectatic cicatrix ( Keratectasia )
P- Perforation
I - Inflammatory glaucoma 
C- Corneal scarring
T-  Toxic iridocyclitis

Thank you :)

~ Pratheek Prabhu

DD of neonatal cloudy cornea

Differential diagnosis of neonatal cloudy cornea - "STUMPED"

T-Tear in Descemet's membrane
M-Metabolic condition
P-Posterior corneal defect
E- Endothelial dystrophy

Thank you :)

~Pratheek Prabhu

Saturday, October 21, 2017

Lesions of visual pathway

Visual pathway starting from retina consists of optic nerve , optic chiasma , optic tracts , lateral geniculate bodies , optic radiations and the visual cortex .
Courtesy :- Comprehensive Ophthalmology 6th edition ; AK Khurana ; Pg.314

Sl . no
Site of lesion
Type of lesion
Optic nerve
Complete blindness on ipsilateral side
Anterior Chiasma
Junctional scotoma
Central chiasma
Bitemporal hemianopia
Lateral chiasma
Binasal hemianopia
Optic tracts / LBG
Incongruous homonymous hemianopia
Part of optic radiations in temporal lobe
Superior quadrant hemianopia (pie in sky )
Part of optic radiations in parietal lobe
Inferior quadrant hemianopia (pie on floor )
Optic radiations
Complete homonymous hemianopia
Visual cortex sparing macula
Congruous homonymous hemianopia
Visual cortex , only macula
Congruous homonymous macular defect
Bilateral Visual cortex , only macula
Bilateral homonymous macular defect

`~ Pratheek Prabhu

Monday, September 18, 2017

Ocular toxoplasmosis and HIV

Here are some fun facts about Ocular Toxoplasmosis and HIV!

Ocular toxoplasmosis usually causes a retinal lesion with inflammation, giving the classical "headlight in the fog"  appearance.

Headlight is the lesion and the fog is due to the inflammation (WBCs).

HIV being an immunodeficient condition, there are lesser number of WBCs and hence there's no fog - Just the headlight.

The drug of choice for treatment of ocular toxoplasmosis is pyrimethamine.

However, it is contraindicated in pregnancy and HIV due to the risk of megaloblastic anemia and neural tube defects, respectively.

In pregnancy, spiramycin is preferred.

In HIV, the preferred drugs are clindamycin, azithromycin or quinolones.

- Written by Dr²

Sunday, September 10, 2017

Enucleation, Evisceration & Exenteration

In this post, we will look at the definition, indications and some few details regarding these 3 ophthalmologic surgeries. 

Tuesday, September 5, 2017

Blood retinal Barrier

Hello :)

There are two blood retinal Barrier (BRB) :-

1. Outer blood retinal Barrier - Formed by tight junction of retinal pigmented epithelium.

2. Inner blood Retinal Barrier - Formed by Muller cells and pericytes surrounding the lining of microvasculature.

That's all for today.
-Upasana Y. :)

Monday, August 21, 2017

Latanoprost and Pilocarpine never go together

Latanoprost increases the uveoscleral outflow of the aqueous humor. Pilocarpine has a constrictive effect on the ciliary body as a whole. Hence, when the two are used together, their effects end up getting nullified with the physician bungling to achieve the target IOP.

That's all!

-Sushrut Dongargaonkar

Thursday, August 17, 2017



Also known as the white pupillary reflex, is an abnormal white reflection from the retina of the eye.
Pathologically it's the absence of the red reflex.

Clinically the pupils appear white rather than the usual black color.

Mnemonic for causes of leukocoria- 


C - Coats disease/ Coloboma/ Cataract
R - Retinoblastoma/ Retinal dysplasia/ ROP/ Retinal         fold
E - Endophthalmitis
A - Astrocytic hamartoma/ Anisometropia
M - Myelinated retinal nerve fiber layer

P - Persistent fetal vasculature/ PHPV
I - Incontinentia pigmenti/ Inflammation (uveitis)
G - Granuloma
M - Melanoma/ Medulloepithelioma
E - Familial exudative vitreoretinopathy (FEVR)
N - Norrie
T - Trauma/ Toxocariasis

Go ahead and add more causes to make your own list!

Shivani Mangalgi
Medicowesome 2017

Tuesday, August 15, 2017

Paramedian pontine reticular formation and MLF

Hello :)

PPRF = Paramedian pontine reticular formation 
MLF = Medial longitudinal fasciculus 

-Upasana Y. :) 

Ptosis in Horner's syndrome vs oculomotor nerve palsy

Hello :)

That's all.
- Upasana Y. :) 

Third nerve palsy

Hello :)

Before starting with the III nerve, Let us understand the term.

According to TABER'S medical dictionary, We need to understand 3 main type of palsy here.

1.NUCLEAR palsy :- Paralysis caused by lesion of the nuclei in CNS.
2.OCULAR palsy :- Paralysis of extraocular nd intraocular muscles.
3.MUSCULAR palsy :- Loss of the capacity of muscle to contract. It may be due to structural or functional disorders
-in the muscle at the myoneural junction,
-in efferent nerve fibres,
-in the cell bodies of nuclei of origin of the brain or of the gray matter of the spinal cord,
-in conducting pathways of the brain or spinal cord,
-in motor centres of the brain.

Third cranial nerve supplies
-Superior rectus
-Inferior oblique
-Medial rectus
-Inferior rectus

-Levator palpebral superioris
-Ciliary body
-Iris sphincter msucle

-Intra-Cavernous sinus
-Superior orbital fissure
-Intra Orbital part

1. Ptosis - paralysis of LPS muscle.
2. Deviation – out, down and intorted (unopposed action of LR and SO).
3. Ocular movements:
• Adduction – MR
• Elevation – SR and IO
• Depression – IR
• Extorsion – IR and IO
4. Pupil is fixed and dilated – paralysis of sphincter pupillae muscle.
5. Accommodation is completely lost – paralysis of ciliary muscle.
6. Crossed diplopia – paralytic divergent squint.
7. Head posture – If the pupillary area is uncovered, head takes a posture consistent with the directions of actions of the paralysed muscles, i.e., head is turned on the opposite side, tilted towards the same side and chin is slightly raised. (Pathways between vestibular nuclei and oculomotor nuclei. These are Intranuclear pathway.)


1. Supranuclear lesions
• Lesions of the cerebral cortex and supranuclear pathway produce conjugate paresis which affect both eyes equally.
• In supranuclear lesions although position and movements of the eyes are abnormal, they maintain their relative co-ordination and produce no diplopia.

2. Nuclear lesions
• Lesions involving purely the third nerve nucleus are relatively uncommon.
• Common causes include ; vascular diseases, demyelination, primary tumors and metastasis
• Lesions involving entire nucleus cause
-an ipsilateral third nerve palsy with ipsilateral sparing and
-contralateral weakness of elevation. 
• Lesions involving paired medial rectus subnuclei (ventromedial nucleus) cause a wall-eyed bilateral internuclear ophthalmoplegia ( WEBINO ) characterised by defective convergence and adduction.

3. Fascicular lesions 
• Causes are similar to nuclear lesions. 
-Benedikt syndrome involves the fasciculus as it passes through the red nucleus and is characterised by ipsilateral 3rd nerve palsy and contralateral extrapyramidal signs such as hemitremor. 

-Weber syndrome involves the fasciculus as it passes through the cerebral peduncle and is characterised by ipsilateral 3rd nerve palsy and contralateral hemiparesis. 

-Nothangel syndrome involves the fasciculus and the superior cerebellar peduncle and is characterised by ipsilateral 3rd nerve palsy and cerebellar ataxia. 

-Claude syndrome is a combination of Benedikt and Nothangel syndromes.

4. Lesions involving basilar part of the nerve 
• As the nerve runs in the subarachnoid space at the base of skull unaccompanied by any other cranial nerve, isolated third nerve palsies are frequently basilar. 
• Causes :
 1. Aneurysms at the posterior communicating artery cause isolated third nerve palsy with involvement of pupil.
 2. Extradural hematomas which may cause tentorial pressure cone with downward herniation of the temporal lobe. This compresses the third nerve as it passes over the tentorial edge. Initially there occurs fixed, dilated pupil, which is followed by a total third nerve palsy. 
3. Diabetes causes isolated 3rd nerve palsy with sparing of the pupillary reflexes.

5. Lesions involving intracavernous part of the nerve 
• Because of its close proximity to other cranial nerves, intracavernous 3rd nerve palsies are usually associated with involvement of the 4th and 6th nerves, and the 1st division of trigeminal nerve.
• In intracavernous 3rd nerve palsy, pupil is spared. Sometimes, pupil may be constricted owing to inv of sympathetics.

• Causes : 
1. Diabetes may cause vascular palsy. 
2. Pituitary apoplexy – may cause a third nerve palsy as a result of hemorrhagic infarction of a pituitary adenoma (after child birth), with lateral extension into cavernous sinus. 
3. Intracavernous lesions – aneurysms, meningiomas, carotid-cavernous fistulae and Tolosa-Hunt syndrome (granulomatous inflammation).

6. Lesions of the intraorbital part of the nerve 
• May cause isolated extraocular muscle palsies or may involve either superior division or inferior division or both. 
• Causes : orbital tumors, pseudotumors, trauma and vascular diseases.

7. Lesions of pupillomotor fibres 
• B/w the brainstem and the cavernous sinus, pupillomotor fibres are located superficially in the superior median quadrant of the nerve.
• They derive the blood supply from the pial blood vessels whereas the main trunk of the 3rd nerve is supplied by vasa nervorum.

I want to thank my teacher for such a beautiful explanation.
I hope it helped.
Do read about the following . (though I will write on this topic also)
1.Injury of Paramedian pontine reticular formation
2. Ptosis in Horner's syndrome and oculomotor nerve palsy.

-Upasana Y. :)