Noor Eye Training center - NETC

Crocodile Tears Syndrome:
▪️Also called Bogorad's syndrome, gustato-lacrimal reflex, paroxysmal lacrimation.
▪️Crocodile tear syndrome or gusto-lacrimal reflex consists of unilateral lacrimation which occurs when a patient eats or drinks.
▪️This rare phenomenon usually follows a Bell’s palsy or a traumatic facial paralysis. It may occur congenitally with Duane’s retraction syndrome.
▪️The most commonly accepted mechanism for the pathogenesis of this abnormal reflex appears to be the misdirection of regenerating gustatory fibers from either the facial or glossopharyngeal nerves. After being injured the nerves may redirect themselves through the greater superficial petrosal nerve to reach the lacrimal gland, and cause ipsilateral tearing when the patient eats.
▪️An alternative hypothesis is that the nerve fibres do not actually regenerate, but rather form an artificial synapse at the site of the injury which allows the crossover of impulses from one fibre to another and interaction between afferent and efferent axons.

Acquired Myopia:
Acquired myopia can be divided into refractive and axial causes.
▪️Things that make the refractive power of the eye greater:
➖Lens nucleus or shape changes (increased curvature or increased refractive index):
¢ Cataract
¢ Diabetes
¢ ROP
¢ Lenticonus
➖Lens repositioning (increased effective lens power):
¢ Ciliary muscle shift:
© Toxemia of pregnancy
© Drugs (topiramate, chlorthalidone, sulfonamides, tetracycline, carbonic anhydrase inhibitors)
¢ Lens movement:
© Anterior lens dislocation
© Peripheral dislocation, bringing the relatively higher power of the lens periphery into the path of light
➖Ciliary muscle tone (increased lens curvature ):
¢ Antihistamines
¢ Miotics
¢ Excessive accommodation
¢ Improper refraction technique (inadequate fogging)
➖Corneal power increase (increased curvature)
¢ Keratoconus
▪️And things that make the eye longer:
➖Congenital or developmental glaucoma
➖Posterior staphyloma
➖Idiopathic progressive myopia
➖Scleral buckle

Cavitary Anomalies of The Optic Disc:
▪️Excavated optic disc anomalies include megalopapilla, peripapillary staphyloma, optic disc coloboma, optic pit, and morning glory disk anomaly (MGDA).
▪️The optic disc anomaly seen in periventricular leukomalacia (PVL) and papillorenal syndrome are also often considered as cavitary anomalies of the optic disc.
▪️In the MGDA and peripapillary staphyloma, a congenital excavation of the peripapillary fundus surrounds and incorporates the optic disc.
▪️Ipsilateral intracranial vascular dysgenesis is seen in some patients with MGDA suggesting that MGDA results from a primary vascular dysgenesis with resulting mesenchymal abnormality.
▪️Peripapillary staphyloma appears to arise as a sequel to a localized disturbance in scleral development.
▪️Optic disc colobomas comprise a clearly demarcated bowl-shaped excavation of the optic disc, generally decentered and deeper inferiorly.
▪️Colobomas result from abnormal fusion of the two sides of the proximal end of the optic cup. They may be accompanied by multiple systemic conditions including the CHARGE association, Walker–Warburg syndrome, Goltz’ focal dermal hypoplasia, and Aicardi syndrome.
▪️Optic disc colobomas may be associated with PAX2 gene mutations as part of the papillo-renal or renal-coloboma syndrome (bilateral optic disc anomalies associated with hypoplastic kidneys).
▪️However, coloboma seems to be an inappropriate terminology to use in the papillo-renal syndrome as there is no evidence that the optic fissure fails to close.
▪️On the contrary, the optic disc anomaly in this condition has been shown to be a form of hypoplasia resulting from hereditary vascular dysgenesis affecting the ocular circulation.
▪️The optic disc cavitation seen with PVL (an abnormally large optic cup and a thin neuroretinal rim contained within a normal-sized optic disc) is also considered by some as a form of segmental optic nerve hypoplasia resulting from retrograde degeneration of axons secondary to injury to optic radiation after the scleral canals have established normal diameter.
▪️Megalopapilla is a generic term for an abnormally large optic disc that does not have the inferior excavation of an optic disc coloboma or the features of a MGDA. It is believed to result from altered optic axonal migration early in embryogenesis.
▪️Optic pit consists of a dysplastic retina that has herniated posteriorly into a collagen-lined pocket through a defect in the lamina cribrosa. The pathogenesis of optic pits is unclear. They are unassociated with systemic anomalies.

Vogt’s striae versus Haab’s striae:
▪️Vogt’s striae are vertical folds at the level of the posterior stroma and Descemet’s membrane, seen in patients of Keratoconus.
➖They occur in the area of maximal thinning and are best seen with a wide slit-lamp beam.
➖These are stress lines that can be made to disappear with gentle pressure at the limbus.
▪️Haab’s striae, or Descemet’s tears, are horizontal breaks in the Descemet membrane seen in primary congenital glaucoma. Haab’s striae are named after Otto Haab.
➖Haab’s straie are usually peripheral tears, concentric with limbus and appear as lines with double contour.
➖Haab’s striae, often oriented horizontally
or curvilinearly, are found in ~25% of eyes diagnosed with primary infantile glaucoma at birth, and in more than 60% of those diagnosed at 6 months of age.

Hirshburg corneal reflex test.

Lipid Keratopathy adjacent to Ghost vessels:
🔹Lipid Keratopathy (LK):
▪️Lipid keratopathy is a disease in which fat deposits accumulate in the cornea, leading to opacification and decrease of visual acuity.
▪️This condition can be idiopathic without signs of previous corneal disease or secondary to ocular or systemic diseases.
▪️Lipid keratopathy is usually associated with abnormal vascularization of the cornea, and the lipid classically deposits adjacent to these vessels.
▪️ Secondary LK typically presents unilaterally with cream-colored opacification adjacent to neovascularization, while idiopathic LK is usually bilateral.

Hypertensive Retinopathy.

Meibomian Gland Dysfunction:
▪️Clinical features of MGD may be subtle to severe and often there is no correlation between symptoms and signs.
▪️The patients’ complaints are non-specific or include burning, redness, grittiness, watering and fluctuating vision.
▪️There is often discomfort after prolonged reading or working on computers.
▪️Thickening, hyperemia and irregularity of the posterior eyelid margin are common features of MGD.
▪️An early sign is pouting of the orifices, which are often capped with a solidified dome of oil.
▪️In health, the meibum is clear while in the diseased state, the consistency varies from cloudy to granular in the initial stages to a thick inspissated tooth-paste-like semisolid plug that is considered as hallmark of the disease.
▪️Another feature often noted is meibomian foam that results from the presence of soaps in the tear film.
▪️Clinical signs of the disease need to be differentiated from morphological changes brought about by age.
▪️The age-related signs are lid vascularity, hyperkeratinisation of the skin of the eyelids, lower lid telengiectasia, upper lid rounding, narrowing of orifices with pouting and decrease gland secretion.
▪️However, these changes are not associated with increased viscosity or opacification of the expressed lipid, which are markers for the disease.
▪️The meibomian glands are visualized through the tarsal conjunctiva on slit-lamp microscopy or with infrared photography (meibography).
▪️The features in meibography are gland dropouts, duct dilatation, hypotranslucent cysts and large hypertranslucent scars (chalazia).
▪️MGD is closely associated with keratoconjunctivitis sicca in 25-40% of cases and is the major cause of evaporative dry eye.
▪️Patients with meibomian gland dropout have been found to have a higher tear evaporation rate.
▪️Ocular discomfort, increased tear evaporation and epithelial changes as evidenced by fluorescein and Rose Bengal staining have been associated with gland dropout in obstructive MGD.
▪️Two other closely associated dermatological conditions are seborrheic dermatitis and rosacea.
▪️MGD is also associated with contact lens intolerance, giant papillary conjunctivitis, chalazia, floppy eyelid syndrome, recurrent corneal erosions and concretions.

Large, mutton fat Keratitic precipitates (KPs)—seen in granulomatous uveitis with its Distribution — Inferior quadrant—base down triangle “Arlt’s triangle”under the influence of gravity and aqueous convection currents.

The Pupil:
1- Rubeosis Iridis 2- Pseudoexfoliation
3- Iris Flocculus. 4- Posterior Synechiae