retinal disorders Flashcards
what are the methods of visualizing the retina ?
direct ophthalmoscope
indirect ophthalmoscope
the sit lamp biomicroscopy
poorly pigmented retina term ?
tigroid fundus
what are the anatomical parts that we divide the retina into ?
central retina
peripheral retina
what are the components of the central retina ?
the macula
the fovea
what are the features of the fovea ?
thinnest part
only has cones no rods
responsible for sharp vision
what are thee 10 layers of the retina ?
nerve fibre layer
ganglion cell layer
inner plexiform layer
inner nuclear layer
outer plexiform layer
outer nuclear layer
photoreceptor layer
RPE
Bruch’s membrane
Choroid
what are the 2 types of photoreceptors ?
RODs and CONES
what is the difference between RODS and CONES ?
cones are for day, color vision and there are three types of them that only exist in the fovea
rods exist outside of the fovea in the retina and are responsible for black and white vision and there are only one type
what are the feature of the retinal pigment epithelium ?
not light sensitive
regulates diffusion
keeps the retina dry from fluids in thee choroid
storing of vitamin A
what is the blood supply of the retina ?
the inner half of the retina - supplied by the central retinal artery
the outer half of the retina - non vascular and receives oxygen and nutrition from the choroid
what are the specific clinical investiigations for the retina ?
fundus fluorescein angiography
Optical coherence tomography
Ultrasound
what is using OCT useful for ?
seeing if there is any macular oedema
effect of glycemic control on retinopathy in DR ?
can delay retinopathy
this can be monitored by HbA1c
what can the findings in DR be attributed to ?
either microvascular leakage
or microvascular occlusion
what are the different presentations of diabetic retinopathy ?
Non proliferative retinopathy
severe non proliferative
proliferative diabetic retinopathy
Advanced diabetic eye disease
what are the other names that also refer to non proliferative retinopathy ?
background diabetic retinopathy
what are the features of non proliferative diabetic retinopathy ?
micro aneurysms
dot and blot hges
hard exudates
soft exudates/ cotton wool spots
intra retinal microvascular abnormalities
venous beading and sausaging
what is the etiology behind cotton wool spots ?
nerve fibre layer infarcts due to ischemia and not true exudates
what allows for the convesioin of non proliferative DR to proliferative ?
we reach this stage once the ischemic tissue begin to release VEGF allowing for new friable vessels to form
what are the two types of differentiated vascularization in proliferative diabetic retinopathy ?
NVD - neovascularization at the disc
NVE - neovascularization elsewhere
what is NVD what complication is NVD highly associated with ?
neovascularization at the disc massive vitreous hge
what are the features of advanced diabetic eye disease ?
massive vitreous hge
traction retinal detachement
neovascular glaucoma
what is the type of glaucoma associated with advanced diabetic eye disease ?
neovascular glaucoma
what is the most common cause of drop of vision in diabetic retinopathy ?
macular oedema
how can ischemic maculopathy be detected ?
FFA
how can macular oedema be treated ?
focal laser and/or anti VEGF
but nothing for macular ischemia
what is the treatment for diabetic retinopathy ?
in addition to control of blood glucose there are three main lines of management :
Focal laser
Intravitreal Injections
Pars plana vitrectomy
what is the aim of using focal laser in DR ?
directed at leaking micro aneurysms aiming at their occlusion with subsequent drying up of the retina
what is the aim of intravitreal injections ?
a combination of Anti-VEGF injections to prevent further vascularization along with triamcinolone
what is the purpose of pars plana vitrectomy ?
to treat advanced complications such as vitreous hge and tractional retinal detachement
what are the arteriosclerotic changes in hypertensive retinopathy ?
copper wire arteriole
silver wire arteriole
AV crossing
dilatation of the distal part of thee vein due to occlusion (banking)
what are the classifications of hypertensive retinopathy ?
Grade I : slight or modest narrowing of the retinal arterioles, with an arterial:venous ratio of >1:2
Grade II : modest to severe narrowing of the retinal arterioles with A:V ratio of <1:2
Grade III: Soft exudates with flame shaped hges
Grade IV: Grade III changes and bilateral optic nerve oedema
what is the most common cause of retinal venous occlusion ?
the most common cause is hypertension/atherosclerosis
what are the risk factors for venous occlusion ?
Ocular HTN
Open angle glaucoma
( pressure from outside )
what are the clinical types of retinal vein occlusion ?
ischemic and non ischemic type
what is the difference in presentations of ischemic and non ischemic retinal vein occlusion ?
ischemic - happens in the elderly , upon waking up and on fundus exam there are many retinal hges
non ischemic - happens in the younger population and is less severe
what can be done in order to differentiate between ischemic and non ischemic retinal vein occlusion ?
FFA
what are the complications off retinal vein occlusion ?
macular edema
Neovascularizatiion of the retina, iris and neovascular glaucoma
Vitreous hge
what is thee treatmeent for retinal vein occlusion ?
in the acute stages a monthly injection of anti iVEGF into the vitreous for up to 6 months for the macular edema
what is the management if neovascularization happen on the iris in cases of retinal vein occlusion ?
pan retinal laser photocoagulation to prevent neovascular glaucoma
what is neovascular glaucoma ?
a severe form of 2ry glaucoma due to the neovascularization of the iris which causes progressive angle closure
what is the main stay treatment for ischemic retinal disease ?
pan retinal photocoagulation
what is the most common cause of retinal artery occlusion ?
in the elderly the most common cause is thrombosis
n the younger population embolization is more common
what are the signs associated with retinal artery occlusion ?
if the occlusion is temporary - transient blindness - amaurosis fugax
if the occlusion persists - thee retina becomes milky white and the thin fovea becomes a red cherry spot due to the contrast
loss of the upper half of vision in branch artery occlusion
what is the treatment for retinal artery occlusion ?
must be treated as a medical emergency and quickly
lowering of the intraocular pressure with massage, paracentesis or mannitol to induce vascular dilatation
other ways include inhalation of 5% carbon dioxide
what is choroidal neovascular membrane ?
the extension of new vessels origination from the choroid , through the brusch membrane and reaching the retina
what are thee main causes of choroidal neovascular membrane ?
age related - and hence AMD
Idiopathic
Degenerative myopia
Iatrogenic - post laser burns
what are the symptoms associated with CNM ?
distortion of the images especially during reading or near work (metamorphopsia)
peripheral vision is usually maintained
what are the signs associated with CNM ?
loss of foveal reflex
yellowish - grey appearance of the fovea
distorted or missing squares on Amsler grid
what is the cause of affection of central vision in CNM ?
macular scarring
what are the two types of AMD ?
wet ( proliferative typee due to CNM )
dry type with no CNM
what are the features of dry AMD ?
drusen yellow spots on the basement membrane of the RPE
central choroidal atrophy
geographic atrophy
what are the features of wet AMD ?
CNVM
what is retinal detachement ?
seperation of the sensory retina from the RPE by subretinal fluid
what are the different types of retinal detachement ?
- primary
- tractional
- exudative
what is the etiology in each type of retinal detachement ?
primary - retinal tears allows for thee leakage of sub retinal fluid between thee neuro-retinal and the RPE causing detachment
traction - fibrous tissue in the vitreous pulls the RPE away from the sensory retina
exudative - accumulation of subretinal fluid in the absence of retiinal tears or tractioin , characterized by shifting subretinal fluid
what is the most common cause of tractional RD ?
proliferative diabetic retinopathy
what is the most common cause of exudative RD ?
choroidal tumors
what are the risk factors associated with primary RD ?
aphakia or pseudophakia
high myopia
trauma
family history of RD
what event occurs right before retinal breaks ?
posterior vitreous detachment
what is thee presentation of PVD ?
posterior vitreous detachment :
sudden onset of floaters and flashers that increases with head movements
what is the main cause of vitreous detachment ?
mostly an aging process
what are the types of retinal tears ?
U shaped tears
rounded holes
what is the clinical picture of retinal breaks ?
floaters and flashers
black curtain coming from one side
loss of central vision n
what is the prophylactic treatment for reetinal deatchment ?
around the retinal breaks , surround it by laser burns
what procedures can be done for retinal detachment ?
scleral buckling
pars plana vitrectomy
what are the Heredofamilial retinal disorders ?
Retinitis Pigmentosa
Stargardt’s disease
what is the presentation of retinitis pigmentosa ?
affection of the rods and cones
appears in the 2nd or 3rd decade
diminshed night vision
spider like lesions i the retinal periphery
no treatment
what is the gold standard for diagnosis of retinitis pigmentosa ?
ERG
electroretinogram
what is the presentation of Stargardt’s disease ?
affection of the macula
presents in the 2nd or 3rd decade
mottled fluorescent of the macular area
no treatment
what is the presentation in branch occlusion of the retinal veins vs artery ?
BRCVO: no macular affection
BRAO: loss of upper half of vision
