What is a reverse APD?
Reverse RAPD and its usage Reverse RAPD, or reverse testing for RAPD, utilizes the swinging flashlight test while evaluating the normal, unaffected pupil for dilation. This finding is present in every RAPD but most examiners are used to only observing the affected pupil during the swinging flashlight test.
What is an APD in ophthalmology?
An Afferent Pupillary Defect (APD) is caused by damage to the neuropathway connecting the eyes and the brain. Your doctor or technician will check for this by shining a handheld light into your eyes and looking for an equal response.
What happens in relative afferent pupillary defect?
Relative Afferent Pupillary Defect (RAPD) is a condition in which pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve (only optic nerve disease occurs in front of the lateral geniculate body).
What causes an afferent pupillary defect?
This relative afferent pupillary defect (RAPD) is caused by a difference in the overall light sensitivity of one retina versus the other (Figure 6, pathway 1).
Why do both eyes constrict at the same time?
The efferent part of the pathway (blue) is the impulse/message that is sent from the mid-brain back to both pupils via the ciliary ganglion and the third cranial nerve (the oculomotor nerve), causing both pupils to constrict, even even though only one eye is being stimulated by the light.
Does retinal detachment cause APD?
For example, a patient with a history of total retinal detachment in one eye would manifest a relative afferent pupillary defect. However, some patients present with sudden, gradual or no known vision loss and manifest an RAPD for the first time in your office.
How do you test for pupil APD?
Most commonly, the presence of an APD is evaluated in office using the swinging flashlight test, in which each pupil is illuminated and the velocity and amplitude of the pupillary response is compared. In a healthy patient, light stimulation into one pupil results in equal constriction of both.
How do you check your pupils for APD?
What is the swinging flashlight test used for?
The ‘swinging light test’ is used to detect a relative afferent pupil defect (RAPD): a means of detecting differences between the two eyes in how they respond to a light shone in one eye at a time.
What part of the brain controls pupil constriction?
The pretectal nucleus projects in turn to the (parasympathetic) Edinger–Westphal nuclei on both sides of the brain stem. Fibres from these nuclei travel with the oculomotor (III) nerves to innervate the ciliary ganglia, which supply the sphincter pupillae muscles (causing both pupils to constrict).
What can cause afferent pupillary defect?
Relative Afferent Pupillary Defect (RAPD, Marcus Gunn Pupil) It is due to damage inoptic nerve or severe retinal disease. It is important to be able to differentiate whether a patient is complaining of decreased vision from an ocular problem such as cataract or from a defect of the optic nerve.
Does amblyopia cause an APD?
Pathology responsible for causing an APD can include significant amblyopia, major retinal issues and optic neuropathy.
Which part of the brain controls pupillary changes?
The pupillary dilation pathway is a sympathetically driven response beginning in the hypothalamus and ending with the contraction of the dilator pupillae muscle.
Can a dense cataract cause and APD?
Thus, a dense cataract causes an RAPD in the contralateral eye by increasing the pupillomotor effectiveness of the stimulus light and that this is the reason why even a brunescent cataract does not cause an RAPD in the same eye.
What drugs can cause constricted pupils?
Narcotic drugs, either legal or illicit, can constrict pupils. These include heroin, morphine, hydrocodone, and fentanyl. Overdose on these drugs can also lead to pinpoint pupils (when eyes don’t respond to changes in light).
What is the difference between reverse RAPD and normal RAPD?
The reverse RAPD is present every time because both pupils dilate when the light swings from the normal pupil to the abnormal pupil but in a reverse RAPD the clinician is observing the normal pupil when the light swings from unaffected to affected eye. ↑ 1.0 1.1 Vejdani MD., Al-Zubidi N. Relative Afferent Pupillary Defect.
What is right RAPD by reverse testing?
When the light swings from the abnormal right pupil with the afferent (and efferent) pupillary defect to the normal left pupil, the left pupil constricts but when the light swings from the normal left pupil back to the abnormal right pupil the examiner observes the left pupil dilating. This is a right RAPD by reverse testing.
How do I determine my APD?
This is known as determining an APD by reverse. Pupils should be round, symmetrical and centered within the iris.
How are APDS quantified and graded?
Various techniques have been described to quantify or measure APDs. These include the use of neutral density filters, cross-polarized filters, and subjective grading based on the amount of initial contraction and subsequent re-dilation of each pupil as the light is swung.