EXTRA Flashcards
(16 cards)
Define APPARENT STRABISMUS (False or Pseudo-strabismus) and give the causes and treatment
It is a condition in which a false impression of ocular deviation is present but on examination, the eyes are straight
usually caused by some normal anatomical variations in early childhood such as the presence of epicanthus fold or the presence of a small or large interpupillary distance
No treatment
Give an account on latent strabismus (Heterophoria)
is the tendency of the eye to deviate which is normal and subconscious
Patient may complain of eyestrain (asthenopia) after visual excretion. No treatment is required just correction of errors of refraction
Define concomitant squint and give the treatment
In concomitant deviations, the deviation remains the same in all the directions of the gaze. The condition may be congenital (esotropia is much more common than exotropia), or acquired. The acquired deviation may be attributed to refractive errors or may be sensory.
The hallmark of concomitant squint is the absence of limitation of ocular motility. Concomitant squint may be unilateral when one eye is always deviating, or alternating if the 2 eyes alternately deviate
Correction of error of refraction
Treatment of amblyopia (lazy eye)
Surgery (weaken the stronger muscle)
Define paralytic squint and discuss the clinical manifestations
n paralytic strabismus, deviation of the eye is caused by paralysis or paresis of one or more of the extraocular muscles. The deviation of the eye varies in different directions of gaze
Binocular diplopia most remarked at direction of paralyzed muscle and abnormal head position.
Children brain suppress blurred vision due to plasticity of their brain
Give the causes of 6th nerve palsy
Intracranial hypertension due to a space occupying lesion
Microvascular diseases such as diabetes and hypertension
In children it is caused by trauma, post viral disease or secondary to severe otitis media.
Because 6th nerve can accompany any increase in intracranial pressure, it is called false localizing sign.
Amblyopia definition and types
a condition of impaired vision in the absence of any organic disease. It is usually unilateral. (lazy eye)
1- Strabismic amblyopia: Constant unilateral strabismus occurring early in life will lead to suppression, which in tum causes amblyopia.
2- Anisometropic amblyopia: Uncorrected anisometropia; the eye with poorer vision may deviate.
3- Sensory deprivation amblyopia: occurs as a result of lack of proper image formation in one eye possibly due to media opacities or fundus lesions.
Discuss the management of amblyopia
- Treatment of the cause.
- Occlusion of the normal eye to force the patient to use the amblyopic eye and/or
- Penalization (blurring the normal eye by instilling cycloplegic drops thus giving an advantage to the weaker eye in near vision).
Enumerate the stages of diabetic retinopathy and mention one diagnostic sign
Non-proliferative DR (background DR): Blot hemorrhages, microaneurysm, possible macular edema and hard exudates
Severe non-proliferative diabetic retinopathy: Signs of ischemia (soft exudates, intra-retinal microvascular abnormalities and dilation of retinal veins
Proliferative diabetic retinopathy (PDR): Ischemic retinal tissue releases (VEGF), which causes the development of new abnormally fragile vessels that can explode causing vitreous hemorrhage and loss of vision.
Advanced diabetic eye disease: Massive vitreous hemorrhage, tractional RD and neovascular glaucoma
Mention the methods of diagnosis and treatment of proliferative diabetic retinopathy
Diagnosis is by fundus examination
Pan retinal photocoagulation; beam directed at leaking microaneurysm, drying them up and also destroys pert of ischemia to limit release of VEGF
Anti-VEGF: treats macular edema and neovascularization
Corticosteroid: Triamcinolone
Pars plana vitrectomy: treats dense non-resolving vitreous hemorrhage and tractional RD
Discuss the complications of CRVO
Macular edema
Neovascularization at retina or neovascularization at iris causing glaucoma
Vitreous hemorrhage
Treatment is monthly injection of anti-VEGF for up to 6 months for macular edema
Treatment of CNVM
Repeated intravitreal injections of anti-VEGF
Special magnifiers for reading if central vision is lost
Enumerate the types of retinal detachments
1) Primary or rhegmatogenous RD :
This is caused by a retinal break, which permits fluid derived from the vitreous to gain access to the subretinal space
2) Tractional RD: Occurs when the sensory retina is pulled away from the RPE by contracting fibrous tissue in the vitreous (vitreoretinal traction). The most common cause is proliferative diabetic retinopathy (PDR)
3) Exudative RD: Results when subretinal fluid, derived from the choroid, gains access to the subretinal space and elevates the retina. Examples include some cases of posterior uveitis such as Vogt Koyanagi Harada disease (VKH), toxemia of pregnancy, and choroidal tumors such as hemangioma or melanoma.
Ocular lesions in herpes simplex
- Palpebral conjunctival follicles
- Punctate epithelial keratitis
- Lid vesicles in herpetic cases
Blood supply of retina
Inner half is supplied by central retinal artery (end artery from ophthalmic A)
Outer half of the retina is a vascular (because it has important photoreceptors) and receives O2 by diffusion from choroid
Enumerate causes of pediatric cataract
Idiopathic
Hereditary
Intra-uterine infections
Metabolic
Chromosomal abnormality (Down)
Traumatic
