DOPT/FT/1B/01
Zhi Ping
Evon Liu
Junice Chong
Goh Wan Ting
V. Shamala
Thursday, February 11, 2010
Wednesday, January 13, 2010
Abnormal pupil condition: Argyll Robertson pupil
What it is
Argyll Robertson pupils (AR pupils) are bilateral small pupils that constrict when the subject focuses on a near object during accommodation, but do not constrict when exposed to bright light. AR pupils are often associated with the presence of syphilis and are extremely uncommon in developed countries.
History
The AR pupil was named after Douglas Moray Cooper Lamb Argyll Robertson, a Scottish ophthalmologist, who noted the association of the pupil condition with syphilis in 1869. Patients with AR pupils usually tested positive for syphilis. The AR pupil then became known as a reliable clinical sign of syphilis. They were formerly known as "Prostitute's pupils" because of their association with tertiary syphilis and because of the convenient mnemonic that, like prostitutes, they "accommodate but do not react".
The AR pupils are a highly specific sign of neurosyphilis. In general, pupils that accommodate during near vision but do not react under light exposure are said to show light-near dissociation. (link?)
(need to include that having AR pupils doesn't mean one HAS syphilis)
Clinical presentation
Typical Argyll Robertson pupils are small and irregular and react to accommodation, but not to light.
Initially, the pupil's response to light may only be sluggish and the accommodation reflex is much more pronounced but eventually, the light reflex disappears.
The exact site of the lesion is often debated but generally believed to be in the rostral mid-brain, proximal to the oculomotor nuclei. In some patients, magnetic resonance imaging studies have localized the lesion to the Edinger-Westphal nuclei.
The AR pupil has become a rare diagnostic sign of neurosyphilis. If neurosyphilis is suspected, examinations may reveal clues such as
- ptosis
- ataxia (using the positive Romberg's test)
- tremors of the mouth/tongue
- outstretched hands/whole body
- diminished/absent tendon reflexes
- impaired vibratory and joint position sense
The AR pupil may also indicate the presence of Sarcoidosis, multiple sclerosis and ocasionally, diabetes mellitus.
How PERRLA is measured
What is PERRLA?
PERRLA is an acronym used to describe the look and function of the patient's eye.
PERRLA represents:
Pupils
Equal
Round
Reactive to
Light and
Accomodation
How is PERRLA measured?
Pupils
Pupils, in PERRLA stands for the presence of pupils in the patients eye. The clinician can simply look into the patient's eye to check for the presence of the pupil or with the help of the pen torch (to better illuminate the eye), check for the presence of the pupil in both eyes.
Equal
This stands for the size of the pupil. The clinician is required to measure the pupil of both eyes and compare whether or not are of equal size. A ruler is used to measure the size of the pupil in both photopic (bright) and scotopic (dark) conditions. To measure the pupil size in a scotopic condition, the Burton's lamp is used to illuminate the eye. The measurement of the pupil size in a scotopic condition can be seen in the second video inserted below.
Round
This represents the shape of the pupil. While a normal pupil should be round,the clinician should take note if the pupil is observed to be of any other shape. The clinician can observe the shape of the pupil with or without the help to a pen torch to illuminate the eye (shown at an angle below the eye and not directly).
Reactivity to Light
This represents the reactivity of the pupil to a light stimulus, meaning which the amount of time taken for the pupil to constrict when slight is shone upon it. The clinician uses a pen torch to shine a beam of light unto the patient's eye and observes the speed of constriction. This is done on both eyes. The speed of constriction should be almost immediate in a normal eye. The clinician will recorded the speed in different grades,3++ being normal reaction to light.
Reactivity to Accommodation
Accommodation occurs when the patient is required to look from a far object to a near object. During accommodation, the pupils will constrict and convergence will be observed as well. The clinician will have to observe this change in pupil size and eye movement. The eye's reactivity to accommodation is recorded down and ranked in the same way as the reactivity to light (3++ being the normal reaction). The first video attached below illustrates the convergence and constriction when fixating form far target to near target as well as divergence and dilation when fixating from near target to far target.
Image1: Illuminated in a scoptopic condition
Image 2: The Burton's Lamp
PERRLA is an acronym used to describe the look and function of the patient's eye.
PERRLA represents:
Pupils
Equal
Round
Reactive to
Light and
Accomodation
How is PERRLA measured?
Pupils
Pupils, in PERRLA stands for the presence of pupils in the patients eye. The clinician can simply look into the patient's eye to check for the presence of the pupil or with the help of the pen torch (to better illuminate the eye), check for the presence of the pupil in both eyes.
Equal
This stands for the size of the pupil. The clinician is required to measure the pupil of both eyes and compare whether or not are of equal size. A ruler is used to measure the size of the pupil in both photopic (bright) and scotopic (dark) conditions. To measure the pupil size in a scotopic condition, the Burton's lamp is used to illuminate the eye. The measurement of the pupil size in a scotopic condition can be seen in the second video inserted below.
Round
This represents the shape of the pupil. While a normal pupil should be round,the clinician should take note if the pupil is observed to be of any other shape. The clinician can observe the shape of the pupil with or without the help to a pen torch to illuminate the eye (shown at an angle below the eye and not directly).
Reactivity to Light
This represents the reactivity of the pupil to a light stimulus, meaning which the amount of time taken for the pupil to constrict when slight is shone upon it. The clinician uses a pen torch to shine a beam of light unto the patient's eye and observes the speed of constriction. This is done on both eyes. The speed of constriction should be almost immediate in a normal eye. The clinician will recorded the speed in different grades,3++ being normal reaction to light.
Reactivity to Accommodation
Accommodation occurs when the patient is required to look from a far object to a near object. During accommodation, the pupils will constrict and convergence will be observed as well. The clinician will have to observe this change in pupil size and eye movement. The eye's reactivity to accommodation is recorded down and ranked in the same way as the reactivity to light (3++ being the normal reaction). The first video attached below illustrates the convergence and constriction when fixating form far target to near target as well as divergence and dilation when fixating from near target to far target.
Image1: Illuminated in a scoptopic condition
Image 2: The Burton's Lamp
Video 1:Reactivity to Accomodation
Videos 2 and 3: Measurement of pupil in scotopic condition
Tuesday, January 12, 2010
Results
The results for our PERRLA tests:
Subject 1: Wan Ting
Pupil-Present in both eyes
Equal (size) - 5mm for both eyes (scotopic condition)
- 3.5mm for both eyes (photopic condition)
Round (shape) - Round for both eyes
Reactivity to
Light - 3++ in both eyes
Accommodation - 3++ in both eyes
Subject 2: Yin San
Pupil-Present in both eyes
Equal (size) - 5mm for both eyes (scotopic condition)
- 4mm for both eyes (photopic condition)
Round (shape) - Round for both eyes
Reactivity to
Light - 3++ in both eyes
Accommodation - 3++ in both eyes
Sunday, January 10, 2010
The Pupillary pathway
The pupillary pathway is made of the afferent pathway (from eye to brain) and the efferent pathway (from brain to eye).
The afferent pathway begins from the Retinal photoreceptors to the Optic nerve and hemidecussate at the optic chiasm, which then leads to the optic tract. It leaves the optic tract just after the LGN (lateral geniculate nucleus) and then proceeds to the Pretectal nucleus which is located in the mid-brain, where a second decussation occurs, and then finally reach the ipsilateral and contralateral Edinger-Westphal group (EWN) of the oculomotor (CN3) nucleus.
Each optic tract carries pupillary fibres from both eyes. This is because of the hemideccusation that takes place at both the chiasm and midbrain.
When the afferent pathway is stimulated, either both eye equally dilate (sympathetic) or constrict (parasympathetic).
The efferent pathway consists of two types- sympathetic and parasympathetic.
For the efferent sympathetic pathway, stimulation is mainly from higher cortical levels, which sends impulses such as fear, pain, anxiety and emotions to the hypothalamus. These cause pupillary dilation (mydriasis).
The efferent parasympathetic pathway starts from the EWN (edinger westphal nucleus) to the Primary fibres that descend from the brain stem and leads to the synapse at the ciliospinal centre of budge ( T1-T3), and then to the secondary neurones leaving the spinal cord. It then sends the impulse through the sympathetic paraspinal chain which leads to the Superior cervical ganglion and, finally, to the postganglionic neurone travelling on the surface of the carotid artery.
At the bifurcation of the internal and external carotid arteries, it may:
1. leave to follow the external carotid artery, resulting in facial sweating
2. join CN6, enter the orbit through CN5, whereby the fibres pass through the long ciliary nerves (branch of CN5) to trigger the Dilator pupillae (pupil dilates).
In general, the efferent pathway consists of two different routes:
a) Parasympathetic- Pupil constricts
b) Sympathetic- Pupil dilates
The afferent pathway begins from the Retinal photoreceptors to the Optic nerve and hemidecussate at the optic chiasm, which then leads to the optic tract. It leaves the optic tract just after the LGN (lateral geniculate nucleus) and then proceeds to the Pretectal nucleus which is located in the mid-brain, where a second decussation occurs, and then finally reach the ipsilateral and contralateral Edinger-Westphal group (EWN) of the oculomotor (CN3) nucleus.
Each optic tract carries pupillary fibres from both eyes. This is because of the hemideccusation that takes place at both the chiasm and midbrain.
When the afferent pathway is stimulated, either both eye equally dilate (sympathetic) or constrict (parasympathetic).
The efferent pathway consists of two types- sympathetic and parasympathetic.
For the efferent sympathetic pathway, stimulation is mainly from higher cortical levels, which sends impulses such as fear, pain, anxiety and emotions to the hypothalamus. These cause pupillary dilation (mydriasis).
The efferent parasympathetic pathway starts from the EWN (edinger westphal nucleus) to the Primary fibres that descend from the brain stem and leads to the synapse at the ciliospinal centre of budge ( T1-T3), and then to the secondary neurones leaving the spinal cord. It then sends the impulse through the sympathetic paraspinal chain which leads to the Superior cervical ganglion and, finally, to the postganglionic neurone travelling on the surface of the carotid artery.
At the bifurcation of the internal and external carotid arteries, it may:
1. leave to follow the external carotid artery, resulting in facial sweating
2. join CN6, enter the orbit through CN5, whereby the fibres pass through the long ciliary nerves (branch of CN5) to trigger the Dilator pupillae (pupil dilates).
In general, the efferent pathway consists of two different routes:
a) Parasympathetic- Pupil constricts
b) Sympathetic- Pupil dilates
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