Therefore, a comparison of pupil size by measurement should be done in bright and dim ambient illuminations (Fig. The filter density is increased until the pupil reactions on the swing test are equal.Īnisocoria is evaluated by determining whether pupillary inequality is caused by a defect in sympathetic or parasympathetic innervation, or is because of a structural disorder of the iris. To measure an RAPD objectively, a neutral density filter is held in front of the uninvolved eye as the swinging flashlight test is performed. The RAPD can be measured subjectively or objectively with neutral density filters. When an afferent defect is present, the pupils become larger when the light is directed to the involved side (see Fig. When both afferent pathways are normal, the pupils remain essentially the same size no matter which side is illuminated. Allow just 3 to 5 seconds of illumination on each side. The test is done in a dimly lit room, with the patient gazing at a distant target and not at the light source. Swinging flashlight test: In this test, light is directed first into one pupil, then moved over quickly to the other pupil,t and repeated several times while both pupils’ response is observed. History of optic nerve disease or retinopathy.The prevalence of physiologic anisocoria is approximately 20%. It is as common in men as in women, in the morning as in the afternoon, in the young as in the aged. Physiologic anisocoria is usually less than 1.0 mm and can change from day to day. Swinging flash-light test (examiner facing patient). This is found in optic neuropathy, retinopathy, Adie’ tonic pupil, Argyll Robertson pupil, Parinaud’ dorsal midbrain syndrome, aberrant regeneration of the third nerve, and diabetes.įigure 19-1. In light-near dissociation (LND) of pupils, there is better pupillary response to near stimuli than to light stimuli.Third-nerve palsy-Dilated pupil accompanied by ptosis and extraocular muscle palsies.Anhidrosis will be present if the lesion involves the sympathetic pathway proximal to the bifurcation of the common carotid artery.
Horner’ syndrome-Miotic pupil accompanied by ptosis and possibly anhidrosis.Pharmacologic pupil-Either miotic or dilated pupil that does not respond to any pharmacologic testing.
Argyll Robertson pupil-The miotic pupils are irregular and do not respond to light with poor dilation in the dark yet good near response.Adie’ tonic pupil-The affected pupil is larger and reacts poorly to light or near stimuli.Anisocoria-Pupillary size difference that may vary between light and dark.With RAPD, there will be a positive swinging flashlight test (Fig.Patients with anisocoria are often asymptomatic or may complain of other symptoms, such as droopy eyelid, blurred vision, focusing problems, or diplopia, depending on any accompanying symptoms. Patients with a RAPD will complain of vision and color loss in the affected eye. Symptoms and signs will vary according to the underlying etiology. Physiologic anisocoria is present when the pupil size difference remains the same in both bright light and in darkness. Constricted pupils can occur with iritis, pharmacologic blockade, Horner’ syndrome, Argyll Robertson pupil, or long-standing Adie’ pupil.
The etiology depends on whether the abnormal pupil is the dilated or constricted pupil.ĭilated pupils can occur from iris sphincter trauma, Adie’ tonic pupil, third-nerve palsy, or pharmacologic blockade. Any disruption of the neural pathway or iris architecture will lead to abnormalities of the pupillary state.Ī relative afferent pupillary deficit (RAPD) or Marcus Gunn pupil will result from a significant unilateral or asymmetric visual deficit caused by retinal or optic nerve disease (optic neuropathy).Īnisocoria is the state where the two pupils are unequal in size. This equality in pupil size is a result of the bilateral symmetrical afferent input to the Edinger-Westphal complex in the midbrain and because of the symmetrical output of the paired sympathetic nuclei in the hypothalamus. Normal pupils are 3 to 4 mm in diameter in ambient light and are relatively equal in size. Pupil size reflects the neural input of both the sympathetic and parasympathetic systems on the dilator and sphincter muscles, respectively, of the iris.
0 kommentar(er)
