For example, if a patient with a retinal detachment in the left eye had had that pupil dilated so that the left pupil was 7 mm and the right 4 mm, and if the measured afferent pupil defect was 0. The article discusses the techniques in detecting relative afferent pupillary defect rapd. Rapd rapd stands for random amplification of polymorphic dna. No direct response in the affected eye and no consensual response in normal eye. Marcus gunn pupil or relative afferent pupillary defect rapd is a medical sign observed during the swingingflashlight test whereupon the patients pupils constrict less therefore appearing to dilate when a bright light is swung from the unaffected eye to the affected eye. Relative afferent pupillary defects in homonymous visual. The detection of a relative afferent pupillary defect. This can be a sign of optic nerve damage, tumor, glaucoma, and a number of other eye issues. However a defect in the afferent nerve does not necessarily have to be in the optic nerve itself, it could be at the optic chiasm likely to be bilateral, or in the optic tract. Relative afferent pupillary defect ophthalight digital. Afferent article about afferent by the free dictionary. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. It is due to major loss of total light input in the affected eye such as massive retinal loss, optic nerve disease, etc. In a very dark room, shine a penlight in the left eye.
It explains the steps in conducting the swinging light test to detect the unilateral or asymmetrical disease of the retina or optic nerve in which the reaction of the pupils in the right and left eyes serves as the physiological basis of the rapd. Argyll robertson pupil one that is miotic and responds to accommodation effort, but not to light. An afferent pupillary defect is an eye condition where one eye is less sensitive to light, and will not contract as sharply in response to light as the unaffected eye. If all is normal, both pupils will remain constricted. The relative afferent pupillary defect rapd, or marcusgunn pupil is an extremely significant and highly objective clinical finding in the examination of the visual system. Even in an unconscious patient, the determination of an rapd can be made. We prospectively studied patients with relative afferent pupillary defects by using the swinging flashlight test. Relative afferent pupillary defect rapd, marcus gunn pupil an rapd is a defect in the direct response. A doctor can identify this defect with the swinging light test, where she moves a light rapidly back and forth between.
Hippus is a twitchy pupil jerkiness and sometimes is normal but can be seen in response to certain drugs. Its when the eyes pupil only slightly contracts or dilates when light shines over it, instead of shrinking immediately like it should. An afferent pupillary defect apd, or marcus gunn pupil results from a lesion of the optic nerve e. Pupil disorders afferent pupillary defect information. Wernicke reported that the pupillary afferent fibre pathway departs from the visual pathway at the optic tract. A marcus gunn pupil, also known as a relative afferent pupillary defect rapd, is a nonspecific sign on physical examination that indicates partial optic nerve dysfunction. Although the relative afferent pupillary defect was described by r. Carrying inward to a central organ or section, as nerves that conduct impulses from the periphery of the body to the brain or spinal cord. An appreciation of the anatomy and understanding of the mechanisms involved in abnormal pupil responses, knowledge of the proper technique of the swinging flashlight test, and an awareness of potential pitfalls in performing this test will aid the physician in the detection of an afferent pupillary defect. The afferent pupillary defect is a reduction in the response of the pupils to light stimulation of an eye with impaired vision, which is detected by comparing the defective response with that. Find it by a swinging flashlight test a medical term.
The advantage to this technique is that small pupillary changes are easily seen under the slitlamp magnification. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other click the link for more information. A relative afferent pupillary defect rapd can be a worrisome exam finding, so an understanding of its possible etiologies is crucial. Relative afferent pupillary defect rapd is a medical sign observed during the swingingflashlight test whereupon the patients pupils constrict less therefore appearing to dilate when a bright light is swung from the unaffected eye to the affected eye. Visual pathways and pupil defects questions and study. Conditions which affect the structure or function of the pupil of the eye, including disorders of innervation to the pupillary constrictor or dilator muscles, and disorders of pupillary reflexes. A relativeafferentpupillary defect, commonly referred to as the marcus gunn pupil, points to asymmetric function of the retina or optic nerve. To assess the validity and reproducibility of quantitating relative afferent pupillary defects with the swinging flashlight test, using a 3second pause technique, and to compare this grading system with that using neutral density filters. Afferent pupillary defect apd or marcusgunn pupil is a condition of the eye where the pupil doesnt dilate appropriately to the level of light reaching it.
Afferent pupillary defect legal definition of afferent. Relative afferent pupillary defect description, causes and risk factors. Afferent pupillary defect an overview sciencedirect topics. Perhaps, the most common eyerelated physical sign in the context of metastatic cancer is cranial nerve palsy, either related to a physical metastasis in the course of the affected cranial nerve or as a paraneoplastic phenomenon.
The list of acronyms and abbreviations related to apd afferent pupil defect. Relative afferent pupillary defect medical student education author. The anterior midbrain, controlling pupillary size, receives a message from the affected eye that illumination is reduced as compared with the. The relative afferent pupillary defect rapd, is also called the marcus gunn pupil, after the ophthalmologist that described the defect in 1883. Translation of afferent pupillary defect in english. A defect of the pupillary reflex caused by a lesion along the pathway of either the parasympathetic supply from the edingerwestphal nucleus to the sphincter pupillae muscle of the iris adies pupil, or the ocular sympathetic supply from the ciliospinal centre to the dilator pupillae muscle of the iris horners.
Cn2 governs sight, and is thus stimulated by light. Rapd, relative afferent pupillary defect, marcusgunn pupil. Several authors have studied rapd in glaucoma patients and its association with visual fields. If a relative afferent pupillary defect is present in the opposite eye, then the pupil will constrict to light and will dilate when the light is shined in the unobserved eye. Relative afferent pupillary defect in eyes with retinal. Relative afferent pupillary defect rapd is caused by lesions of the anterior visual pathway, which produce asymmetric inputs into the pupillomotor of the brain, as first described by levatin 1 in 1959. Optic nerve ii this is the afferent nerve it detects the light, and sends this signal to the brain. An afferent defect of the pupil refers to an abnormal dilation instead of constriction when light hits the eye. Pupillographic evaluation of relative afferent pupillary. Clinical grading of relative afferent pupillary defects. Most often, patients have an ocular or medical history that might explain its presence.
Her visual acuity in both eyes was 2025, and her pupils were symmetric and reactive to light. This person with apd is often unaware of it except by looking in a mirror. 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. Its when the eyes pupil only slightly contracts or. Tatham aj, meirafreitas d, weinreb rn, marvasti ah, zangwill lm, medeiros fa invest ophthalmol vis sci 2014 jan 29. Afferent pupillary defect efferent pupillary defect marcusgunn pupil pupil reaction absent. In the setting of claimed complete visual loss in 1 eye only, other evidence to support optic nerve dysfunction should be present. Here you can read posts from all over the web from people who wrote about ms and relative afferent pupillary defect, and check the relations between. In most cases this would include the presence of a relative afferent pupillary defect rapd see chapter 3. A good understanding of the anatomy of the oculosympathetic pathway is critical when evaluating a patient with horner syndrome. The sympathetic outflow to the iris dilator muscle is a paired right and left, 3neuron chain without decussation figure 4. How to test for a relative afferent pupillary defect rapd.
This will often result in one pupil appearing larger than the other relative afferent pupillary defect rapd. 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. Relative afferent pupillary defect rapd is a condition in which a persons pupils respond differently from one another to light stimuli shone, based on when it is shone into one eye at a time. Estimation of retinal ganglion cell loss in glaucomatous eyes with a relative afferent pupillary defect.
Afferent pupillary defect synonyms, afferent pupillary defect pronunciation, afferent pupillary defect translation, english dictionary definition of afferent pupillary defect. It is due to damage inoptic nerve or severe retinal disease. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit. Abnormalities of the pupil and their characteristics relative afferent pupillary defect rapd also referred to as apd and marcusgunn pupil objective sign of an asymmetrical lesion of the anterior visual pathway retina, optic nerve, chiasm or optic tract seen with major retinal lesions or neurological lesions of the anterior visual.
Relative afferent pupillary defect medical student. An rapd is due to unilateral or asymmetrical disease of the retina or optic nerve. It is a type of pcr reaction, but the segments of dna that are amplified are random. Afferent definition of afferent by the free dictionary. The sign causes much confusion, but in reality is a very simple sign. Latin afferens, afferent, present participle of afferre, to bring toward. Definition of afferent pupillary defect babylon software. Marcus gunn pupil an overview sciencedirect topics.
How to test for a relative a erent pupillary defect rapd. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced. Rapd stands for relative afferent pupillary defect ophthalmology. The firstorder neuron central originates in the hypothalamus and descends through the brainstem into the lateral. Pupilsparing oculomotor nerve palsy was seen in the right eye, but the trochlear nerve cranial nerve iv and the abducens nerve cranial nerve vi were both intact figure 1. Afferent arteriole, afferent loop syndrome, afferent pupillary defect. Isolated relative afferent pupillary defect secondary to. The relative afferent pupillary defect is the most common abnormal pupillary finding, more common than all other pupillary defects combined. Rapd relative afferent pupillary defect ophthalmology. Marcus gunn in 1904, it is clear from his report that the sign was generally known to clinicians of his time. Ask the patient to look at a distant object, and to keep looking at it. This is to prevent the nearpupil response a constriction in pupil size when moving focus from a distant to a near object.
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