Crossed diplopia is seen in exotropia (divergent squint) and uncrossed diplopia is seen in esotropia (convergent squint). I shall first let you experience this before explaining how it happens.
First, keep your index finger about 20-30cm in front of your nose. Now look at the tip of your nose. This simulates convergent squint. You will now be able to see the finger as 2 separate images – one on the left and another on the right. Keeping your eyes fixated at the tip of your nose, close your left eye. The …

Vogt’s triad is seen in postcongestive glaucoma and in treated cases of acute congestive glaucoma
It is characterised by:

Glaucomflecken (anterior subcapsular lenticular opacity)
Patches of iris atrophy
Slightly dilated non reacting pupil (due to sphincter atrophy)

Ref : Comprehensive Ophthalmology, 4th edition by A.K.Khurana; page 230

Correction of pre existing risk factors like blepharitis and conjunctivitis
Apply topical povidone iodine before surgery
Isolate the lid margin and and eye lashes away from the surgical field by careful draping
Sterile surgical techniques

Tear film is composed of 3 layers. They are:

Mucinous layer

Innermost layer
Mucin is secreted by conjunctival goblet cells and glands of Manz
It transforms the corneal surface from hydrophobic to hydrophilic

Aqueous layer

Middle layer
Secreted by the main and accessory lacrimal glands

Lipid layer

Outermost layer

Secreted by meibomian glands

Prevents evaporation of water
Lubricates the eyelids

1. Most common ocular infection-chorioretinitis
2. Most common cause of retinitis in AIDS- CMV
3. Treatment of CMV retinitis- Gangciclovir and foscarnet
4. Most common ocular lesion-Microvasculopathy of conjunctiva and retina
5. Most common and earliest finding of HIV retinopathy-Cotton wool spots
6. Most common ocular neoplasm-Kaposi’s sarcoma
Contributed by Prepg Preparation

Mnemonic for features of Argyll Robertson Pupil: ARP
ARP stands for:

Accommodation Reflex Present (read forwards)
Pupillary Reflex Absent (read in reverse)

Causes of Pseudopapilledema are:

Optic disc drusen
Hypermetropia
Persistent hyaloid tissue

Hollenhorst plaques are cholesterol emboli that are lodged in the retinal artery
They appear bright, yellow and refractile
Mechanism of formation – They originate form atheromatous plaques in the carotid artery containing cholesterol and fibrin
Auscultation of the carotids may reveal a bruit
Clinical significance – Hollenhorst plaques indicate a previous ischemic event in the eye (such as TIA)
It is important to identify and treat the underlying condition

Haller’s cells, also known as infraorbital ethmoid cells are located at the medial roof of the maxillary sinus in the inferior most portion of the lamina papyracea
It is related to the orbital floor

Clinical significance:

It is closely related to the infundibulum and may compromise the ostium of the maxillary sinus
Hence it is a proposed cause of recurrent maxillary sinusitis

Reference:
Otorhinolaryngology, Head and Neck Surgery By Matti Anniko, Manuel Bernal-Sprekelsen, Patrick Bradley

Onodi cells are the posterior most cells of the ethmoid sinus
It is located superolateral to the sphenoid sinus and is in close relation to the optic nerve
It may sometimes surround the optic nerve

Clinical importance:

Attempt to remove the onodi cells during sinus surgery may cause injury to the optic nerve
The onodi cells are a potential cause for incomplete sphenoidectomy

The anatomical landmarks of the sphenoid sinus correlate with that of onodi cells
Hence, the surgeon may mistakenly believe that the sphenoid sinus has been reached

Reference:
Otorhinolaryngology, Head and Neck Surgery By Matti Anniko, Manuel …