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Noor Eye Training center - NETC, Near to sanatorium Street, Kabul (2024)

01/08/2023

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.

$Acquired Myopia: Acquired myopia can be divided into refractive and axial causes. ▪️Things that make the refractive powe...$

19/05/2023

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

18/05/2023

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.

17/03/2023

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.

21/02/2023

Hirshburg corneal reflex test.

11/02/2023

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.

28/01/2023

Hypertensive Retinopathy.

06/01/2023

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.

03/01/2023

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.

28/11/2022

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

11/11/2022

Mittendorf dot :
▪️A Mittendorf dot is a small, circular opacity on the posterior lens capsule, classically nasal in location, which represents the anterior attachment of the hyaloid artery.
▪️The hyaloid artery is present during gestation and typically regresses completely. Failure to do so can lead to benign findings, such as a Mittendorf dot or a Bergmeister's papilla, or pathologic changes as seen in persistent fetal vasculature syndrome.
‏Though Mittendorf dot can be associated with posterior lenticonus and posterior polar cataract, it is often asymptomatic and does not require treatment

11/11/2022

Straatsma Syndrome :
▪️Straatsma et al first described Straatsma syndrome in 1979 in a case series of 4 patients exhibiting unilateral myelinated retinal nerve fibers in association with myopia, amblyopia, and strabismus.
▪️Today, the traditional triad of unilateral myelinated retinal nerve fibers, myopia, and amblyopia is enough to make the diagnosis of Straatsma syndrome.
▪️Variations of the triad include a “reverse Straatsma syndrome,” where patients exhibit hyperopia instead of myopia, and additional findings of nystagmus or strabismus does not preclude one from the diagnosis.
▪️Although Straatsma syndrome has traditionally been unilateral, a case of bilateral Straatsma syndrome and a case of bilateral reverse Straatsma syndrome have been reported.
▪️Most documented descriptions of the myelination in Straatsma syndrome are unilateral and are often discrete wedge-shaped patches that corresponded with the nerve fiber distribution.

09/11/2022

Pathway of Near Reflex:
Near accommodative triad
▪️The near/accommodative response is a three-component reflex that assist in the redirection of gaze from a distant to a nearby object. It consists of a pupillary accommodation reflex, lens accommodation reflex, and convergence reflex.
▪️Afferent pathway for pupillary constriction, lens accommodation, and convergence: Afferent input from the retina is sent to the lateral geniculate nucleus via the optic tract. Fibers from the LGN then project to the visual cortex.
▪️Efferent pathway for pupillary constriction: Efferent parasympathetic fibers from the E-W nucleus project via the oculomotor nerve to the ciliary ganglion and then short ciliary nerves to innervate the iris sphincter muscle to cause pupillary constriction.
▪️Efferent pathway for lens accommodation: Efferent parasympathetic fibers from the E-W nucleus project via the oculomotor nerve to the ciliary ganglion and then short ciliary nerves to innervate the ciliary muscle to cause contraction. Contraction of the ciliary muscle allows the lens zonular fibers to relax and the lens to become more round, increasing its refractive power.
▪️Efferent pathway for convergence: Efferent fibers from the medial re**us subnucleus of the oculomotor complex in the midbrain innervate the bilateral medial re**us muscles to cause convergence.
▶️ Ophthalmologic considerations:
🔹Deficits in accommodation are usually acquired due to aging and presbyopia.
🔹Isolated accommodation deficits can occur in healthy persons or in patients with neurological or systemic conditions (such as in children after a viral illness and in women before or after childbirth).
🔹Accommodation insufficiency is also less commonly associated with primary ocular disorders (e.g. glaucoma in children and young adults causing secondary atrophy of the ciliary body, metastases in the suprachoroidal space damaging the ciliary neural plexus, ocular trauma), neuromuscular disorders (e.g. myasthenia gravis, botulism toxin, tetanus), focal or generalized neurologic disease (e.g. supranuclear lesions, encephalitis, obstructive hydrocephalus, pineal tumors, Wilson disease), trauma, pharmacologic agents, and various other conditions.
🔹Light-near dissociation describes constriction of the pupils during the accommodative response that is stronger than the light response, and it is the primary feature of Argyll Robertson pupils in patients with neurosyphilis.
🔹Light-near dissociation can also occur in patients with pregeniculate blindness, mesencephalic lesions, and damage to the parasympathetic innervation of the iris sphincter, as in Adie’s tonic pupil, described below.
🔹Adie’s tonic pupil syndrome is a relatively common, idiopathic condition caused by an acute postganglionic neuron denervation followed by appropriate and inappropriate reinnervation of the ciliary body and iris sphincter. Immediately following denervation injury, there is a dilated pupil that is unresponsive to light or near stimulation. Ciliary muscle dysfunction gradually improves over several months as injured axons regenerate and reinnervate the ciliary muscle, and the pupil becomes smaller over time. While the near response of the pupil begins to improve, the light response remains impaired, causing light-near dissociation.

09/11/2022

Hirschberg’s Light Reflex Test:
➖It gives a fair estimate of the angle of deviation.
➖The test is done only for near because the examiner must observe the corneal light reflex (Purkinje Sanson image-I) from behind the light source.
➖The patient is asked to fixate on a light source at 33 cm and the position of the light reflex is noted in both the eyes.
➖If it is situated at the edge of pupil it is 15°, at the midway between the pupillary margin and the limbus—30°, and at the limbus—45°, Beyond the limbus it is more than 45° (1° = 2 prism diopters and hence the angle of deviation in prism diopters can be obtained; 1 mm of decentration of light reflex is equal to 7° of squint.
➖In esodeviation the light reflex is decentered in temporal direction, in exodeviation it is decentered in nasal direction, and for vertical squints it is decentered above or below the pupil.

05/11/2022

Diabetic Retinopathy:
Cotton-wool Spots (Soft Exudates):
▪️Cotton-wool spots are microinfarctions of the nerve fiber layer that appear clinically as gray and semiopaque lesions with poorly circumscribed, feathery edges. They frequently have striations running parallel to the nerve fiber layer and occur around blood vessels.
▪️The lesions were first observed microscopically as cellular appearing bodies with a “psuedonucleus” in the nerve fiber layer and given the name cytoid bodies.
▪️They represent swollen nerve endings in the areas of ischemia. The swollen nerve endings are caused by the accumulation of cytoplasmic debris due to the interruption of axoplasmic flow.
▪️Cotton-wool spots are not specific to diabetic retinopathy and can occur in a variety of disease processes, including systemic hypertension, retinal vein occlusions, and acquired immunodefi ciency syndrome (AIDS).

05/11/2022

Diabetic Retinopathy:
Intraretinal microvascular abnormalities(IRMAs):
▪️IRMAs refer to shunt vessels and neovascularization within the neural retina located in areas of dilated capillaries and retinal nonperfusion that may be associated with leakage, hard exudates, and hemorrhage.
▪️IRMAs is a nonspecific term that was given to avoid the controversy of whether new tortuous, hypercellular retinal vessels in areas of occluded capillaries and nonperfused retina represent either retinal neovascularization, aberrant forms of aneurysms, or preexisting vessels that became dilated “shunts” in areas of nonperfusion.
▪️Histologically, IRMAs have been described as thin-walled dilated vessels in the inner retina composed of endothelium with a thickened basement membrane and a decreased number of surrounding pericytes.
Credit: Diabetes and Ocular Disease.

25/10/2022

Fuchs Uveitis Syndrome:

29/09/2022

Phlyctenular conjunctivitis.

29/09/2022

Mechanism of visual loss in Diabetes.

21/09/2022

Familial Exudative Vitreoretinopathy:
▪️Familial exudative vitreoretinopathy (Criswick–Schepens syndrome) is a slowly progressive condition characterized by failure of vascularization of the temporal retinal periphery, similar to that seen in retinopathy of prematurity.
▪️Inheritance is AD and rarely XLR or AR, with high penetrance and variable expressivity; four genes in a common pathway have been implicated.
▪️Presentation is in childhood. The prognosis is frequently poor, especially with early aggressive onset.
▪️Signs:
○ High myopia may be present.
○ Stage 1: peripheral avascularity. There is abrupt termination of retinal vessels at the temporal equator. Vitreous degeneration and peripheral vitreoretinal attachments are associated with areas of ‘white without pressure’. Vascular straightening may be present.
○ Stage 2: peripheral vascular tortuosity and telangiectasia progresses to preretinal fibrovascular proliferation, with or without subretinal exudation.
○ Stage 3: tractional and/or rhegmatogenous macularsparing retinal detachment, with or without exudation.
○ Stages 4 and 5 are macula-involving and total retinal detachment, respectively.
○ Vitreous haemorrhage, cataract and neovascular glaucoma can occur.
Credit: Kanski Clinical Ophthalmology

21/09/2022

Aging of cornea

26/08/2022

Eponymous Signs of Thyroid Ophthalmopathy:
▪️Lid Signs:
• Dalrymple’s Sign: Lid Retraction.
• Von Graefe’s Sign: Lid lag of the upper eyelid on downward gaze.
• Vigoroux Sign: Eyelid fullness/swelling. (Figure 1)
• Grove Sign: Resistance to pulling down the retracted upper lid.
• Rosenbach's Sign: Fine tremors of the eyelids when closed.
• Gifford’s Sign: Difficulty in everting upper lid.
• Enroth Sign: Edema of lower lid. (Figure 1)
• Boston’s Sign: jerky irregular movement of upper lid on downward gaze.
• Kocher’s Sign: Increased lid retraction with visual f ixation (staring look). (Figure 2)
• Abadie Sign: Spasm of the levator palpebrae superioris muscle with retraction of the upper lid.
• Riesman's sign: Bruit heard over the closed eye with a stethoscope.
▪️Facial Signs:
• Stellwag Sign: Incomplete and infrequent blinking (staring look).
• Joffroy Sign: Absent creases in the forehead on superior gaze. (Figure 3)
• Jellinek's Sign: Hyperpigmentation of the superior eye folds.
• Hertoge’s Sign: Loss of the lateral third of eyebrows.
• Sainton’s sign: Delayed forehead wrinkling on up gaze.
▪️Extra-Ocular Muscle Signs:
• Möbius Sign: Inability to converge. (Figure 4)
• Ballet Sign: Restriction of one or more extraocular muscles.
• Jendrassik's Sign: Limitation of abduction and rotation of eyeballs.
• Suker’s Sign: Poor fixation on abduction.
▪️Pupillary Signs:
• Cowen’s Sign: Jerky pupillary constriction to light.
• Lowy’s Sign: Mydriasis with instillation of lower concentration of adrenaline.
• Knies’s sign: Unequal dilatation of pupil in dim light.
▪️Others:
• Goldzeiher’s Sign: Deep injection of the bulbar conjunctiva. (Figure 5)
• Payne Trouseau Sign: Globe luxation.
• Sattler Sign: Increased intra-ocular pressure in upgaze.

17/07/2022

Layers of Retina affected in Diabetic Retinopathy:
➖Cotton Wool Spots: Nerve fibre layer.
➖Microaneursyms: Inner nuclear layer.
➖Dot blot hemorrhages: Inner nuclear & Outer plexiform layer.
➖Flame-shaped hemorrhages: Nerve fibre layer.
➖Hard exudates: Outer plexiform layer.