Magnetic resonance imaging in patients with unexplained optic neuropathy.

PURPOSE: To investigate the anatomic relation between the optic nerve and the adjacent intracranial internal carotid artery (ICA) in patients with unexplained optic neuropathy. METHODS: Coronal magnetic resonance images (MRIs) of 20 patients with unexplained optic neuropathy and 20 age-matched controls were evaluated with digitizing software. RESULTS: The distance between the optic nerve and ICA was significantly less on the side ipsilateral to the atrophic optic nerve than either the study group's contralateral optic nerve-ICA distance (P<0.001) or the control group's optic nerve-ICA distance (P<0.001). The diameter of the atrophic optic nerves was significantly less than either the diameter of the study group's contralateral normal nerves (P=0.008) or the control group's nerves (P<0.001). There was no significant difference between the diameters of the ICA flow voids adjacent to the atrophic optic nerves versus either the study group's contralateral ICA flow voids (P=0.91) or the control group's ICA flow voids (P=0.74). CONCLUSIONS: The authors speculate that the intimate relation between the optic nerve and adjacent ICA may be important in the development of unexplained optic neuropathy. The ICA need not appear abnormal in MRIs.

Atonic pupil after cataract surgery.

We report and describe the clinical findings of three patients who developed atonic pupil after uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens implantation. All patients had normally reactive pupils one day postoperatively, but after two weeks, the pupils were dilated and nonreactive to light, accommodation, and miotics. To estimate the incidence of atonic pupil after cataract surgery, we sent a survey on the frequency, clinical features, and possible etiologies of this syndrome to members of the American Society of Cataract and Refractive Surgery. Of the 567 respondents, 60% had seen at least one case of atonic pupil in the past five years; they reported a total of 1543 cases during that time. This is probably a conservative figure since many cases undoubtedly go unnoticed because of a lack of visual disturbance. We believe this condition occurs more frequently than previously reported. The atonic pupil should be recognized as a possible complication of cataract surgery that should be included in the preoperative consent form.