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Objective: The purpose of the study is to determine the amount of subarachnoid fluid of the optic nerve in normal adults using magnetic resonance (MR) imaging and to investigate whether the subarachnoid fluid is displaced in abduction as assumed by the 30 degree echographic test., Design: The design was a prospective observation study., Participants: Twenty-one healthy headache-free adults participated. Ten (48%) were men and 11 (52%) were women with a mean age of 34.3 +/- 7.9 years., Intervention: Both optic nerves were examined in primary and 45 degrees right and left gazes with T2 fast-spin echo fat-suppressed coronal MR imaging in quadrature head coil. Four MR images, 4 mm apart, starting from 4 mm posterior to the globe were obtained for both nerves simultaneously with an imaging time of 2 minutes and 24 seconds per gaze., Main Outcome Measures: Optic nerve and sheath diameters were measured., Results: Mean nerve diameters were 3.2 +/- 0.4 mm anteriorly to 2.6 +/- 0.4 mm posteriorly, and mean sheath diameters were 5.2 +/- 0.9 mm anteriorly to 3.9 +/- 0.4 mm posteriorly. Optic sheath diameters did not change significantly in abduction or adduction., Conclusions: Magnetic resonance imaging can be used effectively to determine the amount of subarachnoid fluid of the optic nerve. In normal adults, the amount of optic nerve subarachnoid fluid is variable and may be substantial. The authors' MR findings show that optic nerve subarachnoid fluid is not displaced significantly with abduction or adduction.

Purpose: To devise and evaluate a rapid, accurate, and cost-effective method of detecting neuro-ophthalmologic visual field defects., Methods: One hundred fifty-nine consecutive patients were evaluated with 76-point, central 30 degree automated static threshold perimetry on the Humphrey Visual Field Analyzer, as well as by a 76-point, central 30 degree suprathreshold examination with the central reference levels set at 2 or 4 dB lower than the estimated normal median central reference level adjusted for age. Six masked readers reviewed the fields. Their readings were compared with those of the other observers, as well as with the final diagnoses as determined from all available clinical information., Results: In detecting abnormality, the full-threshold 30 degree test had a sensitivity (percent of eyes with true field defects identified by the field test) of 93 percent or 99 percent (depending on whether borderline results were counted as a positive or negative test) and a specificity (percent of cases without true field defects appropriately identified by the field test) of 71 percent or 91 percent. In comparison, the 4-dB offset suprathreshold test had a sensitivity (averaged over all reviewers) of 79 percent or 87 percent and a specificity of 81 percent or 89 percent, whereas the 2-dB test had a sensitivity of 87 percent or 94 percent and a specificity of 73 percent or 85 percent. The mean duration of the suprathreshold tests was 3.5 +/- 1.0 minute, compared with 14.8 +/- 2.8 minutes for the full-threshold technique., Conclusion: The central 30 degree, 76-point, 2-dB offset suprathreshold automated perimetry is more rapid and nearly as effective as the full-threshold test in detecting visual field abnormalities due to neuro-ophthalmologic disease. More quantitative, full-threshold perimetric strategies should be used in all equivocal cases and to follow progression of established disease.

Purpose: Because simple anisocoria is believed to decrease in bright light, the authors determined the prevalence of simple anisocoria under different lighting conditions., Methods: The authors measured the pupil size of 104 healthy subjects with infrared videography at four clinically accessible light levels: darkness; darkness with a hand-held light shining from below; room light; and room light with the hand light shining from below., Results: Of the 104 subjects, 40 (38%) were men and 64 (62%) were women. The ages ranged from 12 to 71 years (mean, 36.3 +/- 12.5 years). The mean decrease in pupillary diameter from darkness to the brightest condition was 1.89 mm. Based on the traditional definition of a pupillary diameter difference of 0.4 mm or greater, the prevalence of simple anisocoria decreased from 18% in darkness to 8% in room light with the hand-held light shining from below. The prevalence of anisocoria varied considerably when other definitions were used. Repeated measures analysis of variance showed that pupillary area difference decreased with brighter conditions (P = 0.026). However, the ratio of the pupillary areas did not change with brighter conditions (P = 0.666)., Conclusions: The prevalence of simple anisocoria decreases with brighter conditions based on pupillary diameter difference. However, this decrease is not apparent when anisocoria is expressed as pupillary area ratio. Those clinicians who measure pupils will find that simple anisocoria decreases in bright light. However, with gross observation where perception of an anisocoria may be related more to the ratio of the pupillary areas, simple anisocoria may not seem to change much with brighter conditions.

Background: Two cases of sympathetic ophthalmia occurring after noncontact neodymium:YAG (Nd:YAG) cyclotherapy have previously been reported. In each case, the patient had undergone filtering surgery in the exciting eye. Although in each case Nd:YAG cyclotherapy was the last surgery performed, the inciting event of sympathetic ophthalmia was unclear., Methods: The authors studied three additional patients who developed sympathetic ophthalmia after Nd:YAG cyclotherapy for glaucoma., Results: Two patients developed sympathetic ophthalmia 4 months after noncontact Nd:YAG cyclotherapy, and 1 patient developed sympathetic ophthalmia 18 months after contact Nd:YAG cyclotherapy. All patients had previous cataract extractions but no filtering surgery in the exciting eye. Clinical features included chronic iridocyclitis, choroidal folds, Dalen-Fuchs nodules, and optic disc edema. Combining these cases with the two previously reported cases, the incidence of sympathetic ophthalmia at our institution thus far is 5.8% (4 of 69) and 0.67% (1 of 150) after noncontact and contact Nd:YAG cyclotherapy, respectively., Conclusions: The incidence of sympathetic ophthalmia after Nd:YAG cyclotherapy is high compared with other ocular procedures. The clinician should vigilantly monitor patients after Nd:YAG cyclotherapy and report additional cases that may have occurred at other institutions.

Purpose: The effect of mydriasis on Goldmann visual field area in patients with retinitis pigmentosa has not been suitably defined. The aim of this study is to determine whether visual field area in these patients varies with pharmacologic mydriasis., Methods: Fifteen adult patients with retinitis pigmentosa were studied prospectively. Goldmann visual fields with II4e and V4e isopters were obtained in both eyes before and after full pharmacologic mydriasis of the right eye. The isopter areas were quantified and analyzed to determine the effect of mydriasis on visual field area., Results: The difference in the right eye isopter areas was compared with the difference in the left eye isopter areas using paired t tests, where the differences were computed from areas obtained before and after dilation of the right eye. Mydriasis had no significant effect on the visual field in terms of isopter area difference (II4e, P = 0.87; V4e, P = 0.45) and percent change in isopter area (II4e, P = 0.81; V4e, P = 0.24)., Conclusion: Pharmacologic mydriasis had no appreciable effect on the Goldmann visual field area in a selected group of patients with retinitis pigmentosa. These findings suggest that visual fields of such patients obtained in the dilated or undilated state can be meaningfully compared.

Dural sinus hypertension from cerebral venous outflow impairment is a cause of pseudotumor cerebri. The authors documented six such patients: two with unilateral neck dissection, one with surgical ligation of the dominant sigmoid sinus, two with thrombosed central intravenous catheterization, and one with dural sinus thrombosis. The site of cerebral venous outflow obstruction was variable and identified in three patients with computed tomography, conventional magnetic resonance imaging, magnetic resonance angiography, and/or angiography. Magnetic resonance angiography used in two patients characterized the venous flow pattern and identified the site of obstruction, confirming magnetic resonance angiography as an effective noninvasive blood flow technique in diagnosing and following these patients. Three patients were treated successfully with medical therapy and one patient with optic nerve fenestration. The two patients with thrombosed central venous catheters had serious systemic illnesses and suffered permanent visual loss.

Humphrey visual fields (30-2 program) were performed on 24 otherwise healthy patients before and after cataract extraction to examine the effect of cataract on automated visual fields. All patients met reliability index criteria and recovered visual acuity of 20/25 or better. The effect of learning associated with repeated testing was controlled with visual fields of the fellow eye. Although a greater absolute threshold recovery occurred in the central region of the visual field after cataract extraction, the percent of threshold recovery did not vary across the visual field except for the most peripheral testing points, which demonstrated less recovery. Thus, cataracts depress an automated visual field fairly uniformly. Clinical grading of cataracts by a single experienced clinician was generally a poor predictor of visual field loss. Only the presence of posterior subcapsular plaque in the visual axis and the preoperative visual acuity correlated significantly with postoperative central threshold recovery. Pattern standard deviation remained unchanged after cataract removal, confirming it as a useful way of estimating visual loss from cataracts.

The relative afferent pupillary defect (RAPD) was measured with neutral density filters in ten patients, each of whom had a dense cataract in one eye only. In each instance, the cataract reduced visual acuity to counting fingers or worse, whereas visual acuity in the other eye was 20/25 or better. All patients with mature or nuclear cataracts had a measureable RAPD in the other eye (mean, 0.44 log unit). In each instance, after extraction of the cataract, the RAPD disappeared. 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. In addition, two clinical cases are reported. One case records the development of a cataract in an eye with a preexisting RAPD resulting from optic neuritis; as the cataract became more opaque, the afferent defect became smaller and finally was reversed. The other case shows that a traumatic cataract can produce an RAPD in the contralateral eye. Thus, when an afferent pupillary defect is seen in an eye with a cataract, a visual pathway defect in that eye should definitely be suspected.