NEUROFTALMOLOGIA Flashcards
Que isso?
blefaroptose
Que isso?
partial third nerve palsy
que isso?
horner
Imagem pra levar pra vida da movimentação ocular extrinseca
complete
The six eye movement systems can be functionally divided into those that hold images of a target steady on the retina and those that direct the fovea onto an object of interest. The former category includes (1) ____________, which holds the image of a stationary object on the fovea when the head is immobile; (2) ____________, which holds the image of a target steady on the retina during brief head movements; and (3) ______________, which holds the image of a target steady on the retina during sustained head movements.
The six eye movement systems can be functionally divided into those that hold images of a target steady on the retina and those that direct the fovea onto an object of interest. The former category includes (1) the fixation system, which holds the image of a stationary object on the fovea when the head is immobile; (2) the vestibular system (or the vestibulo-ocular reflex), which holds the image of a target steady on the retina during brief head movements; and (3) the optokinetic system, which holds the image of a target steady on the retina during sustained head movements.
The latter category, systems that direct the fovea onto an object of interest, includes
(1) ______________, which brings the image of an object of interest rapidly onto
the fovea; (2)______________, which holds the image of a small, moving target on the fovea; and (3)___________, which moves the eyes in an opposite direction, so that images of a single object are held simultaneously on both foveae.
The latter category, systems that direct the fovea onto an object of interest, includes
(1) the saccadic system, which brings the image of an object of interest rapidly onto
the fovea; (2) the smooth pursuit system, which holds the image of a small, moving target on the fovea; and (3) the vergence system, which moves the eyes in an opposite direction (i.e., convergence or divergence) so that images of a single object are held simultaneously on both foveae.
O sistema de fixação visual não é simplesmente o olho parado, uma série de micromovimentos ocorrem para manter o objeto fixado na fovea. Quais esses 3 movimentos?
1- Microsacades
2- Microdrift: smooth pursuit
3- Microtremor
Estruturas supratentoriais responsaveis pela fixação visual:
Parietal eye field
Area 8 de brodmann
Cortex pre frontal dorsolateral
Estruturas infratentoriais responsaveis pela fixação visual:
- Substantia nigra pars reticulata in the basal ganglia
- Rostral pole of the superior colliculus
Mnemonic for vestibular nystagmus quick phase:
COWS
Cold (or lesion), eyes beat in Opposite direction to the side of lesion;
Warm (or stimulation), eyes beat in Same direction as the side of stimulation
Desenhe a via do VOR do canal anterior e posterior!!!!!!!
Downward head acceleration (chin down) stimulates both _____________
■ Upward head acceleration (chin up) stimulates both ____________________
■ Head roll to the right stimulates both ____________ and _______________
Downward head acceleration (chin down) stimulates both anterior canals (ACs) so
that both eyes rotate upward.
■ Upward head acceleration (chin up) stimulates both posterior canals (PCs) so that
both eyes rotate downward.
■ Head roll to the right stimulates both right AC and PC so that both eyes roll to oppo-
site shoulder (upper pole of right eye incyclotorts and that of the left eye excyclotorts).
Purkinje cells in the flocculus and ventral paraflocculus (FL/VPF) of the cerebellum
send more inhibitory projections to the AC than to the PC pathways in the vestibular nucleus. Lesion of FL/VPF removes this asymmetric inhibition, uncovering an underlying AC bias. Thus,lesion of the flocculus and ventral paraflocculus typically causes_________
downbeat nystagmus
A peripheral vestibular lesion usually causes mixed horizontal and
torsional nystagmus. How can you explain this in a semicircular channels point of view?
No caso de lesões periféricas eu tenho os tres canais afetados de um lado ( anterior, posterior e horizontal).
Isso causa uma despolarização do lado esquerdo que desvia meu olhar para direita e tbm com que meus olhos sofram uma torção anti-horaria. Com isso há uma correção rapida para esquerda + uma torção horaria, gerandoum nistagmo horizonto-torsional para esquerda
Lesion of RPC + LPC =Unopposed RAC + LAC =__________________
■ Lesion of LAC + LPC =Unopposed RAC + RPC = __________________
Lesion of RPC + LPC =Unopposed RAC + LAC =↑ (downbeat nystagmus with upward
slow phase)
■ Lesion of LAC + LPC =Unopposed RAC + RPC = (torsional nystagmus with counter-
clockwise slow phase from patient’s point of view)
■ Therefore, a central vestibular lesion causes purely vertical or purely torsional
nystagmus.
Floculo e paranodulo controlam quais componentes do VOR?
sua adaptação e o armazenamento de velocidade do VOR que ajuda a prolongar a resposta do VOR
flocculus and ventral paraflocculus are lesioned so that visual fixation is impaired, causing a specific type of nystagmus called?
periodic alternanting nystagmus
Treina os 3 passos de Bielschowsky ai vai:
Use a ferramenta online pra ajudar
Faz o pathway do skew deviation:
gogogogo
Faz o pathway do VOR dos canais semicirculares anteriores e posteriores
Quais as 4 características de uma sácade?
1- Velocidade
2-Duração
3-Precisão
4-Latencia(tempo de inicio)
Exemplo de doenças em cada uma dessas condições das sácades:
Abnormal velocity____________________
Increased latency_________________
Inaccuracy________________
Inappropriate saccades_____________
Abnormal velocity (e.g., saccades are too slow in spinocerebellar ataxia type 2)
Increased latency (e.g., ocular motor apraxia)
Inaccuracy (dysmetria; e.g., cerebellar lesions usually cause hypermetria)
Inappropriate saccades (e.g., saccadic intrusions and oscillations)
