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Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs. winter. Fifty-two participants (mean age 67.4 years; 30 with bilateral cataracts and 22 age-matched controls with clear lenses; pseudophakes) were tested twice, once in summer and once in winter. At each test session we assessed the electroretinogram and pupil responses during daytime and we determined melatonin suppression, subjective sleepiness and mood in response to light exposure in the evening. Circadian rest-activity cycles and sleep from activity recordings were also analyzed for both seasons. Both groups had similar visual function. There were no seasonal differences in the electroretinogram. For the pupil responses to bright blue light, the post- illumination pupil response (PIPR) was greater in winter than summer in pseudophakes, but not in cataract participants, whereas melatonin suppression to acute light exposure showed no differences between both groups and seasons. Overall, intra-daily variability of rest-activity was worse in winter but participants felt sleepier and reported worse mood at the laboratory in evening time in the summer. Those with cataracts had poorer sleep quality with lower sleep efficiency, and higher activity during sleep in winter than summer. In this study, the PIPR showed a seasonal variation in which a larger response was found during winter. This variation was only detected in participants with a clear intraocular lens. In the cataract group, visual function was not impaired yet these participants showed a lack of seasonal changes in the pupil response to blue light and poorer sleep in winter. These findings raise the question for tailored lighting conditions for cataract patients in order to counter potentially deleterious effects of living with chronically lower light exposure.

Herein, we report a patient who had an isolated sixth nerve palsy due to a petrous apex cholesterol granuloma. The sixth nerve palsy appeared acutely and then spontaneously resolved over several months, initially suggesting a microvascular origin of the palsy. Subsequent recurrences of the palsy indicated a different pathophysiologic etiology and MRI revealed the lesion at the petrous apex. Surgical resection improved the compressive effect of the lesion at Dorello's canal and clinical improvement was observed. A relapsing-remitting sixth nerve palsy is an unusual presentation of this rare lesion.

BACKGROUND Idiopathic intracranial hypertension (IIH) is a well-characterized syndrome, most commonly affecting obese women of childbearing age. Differences in its prevalence have been reported in various populations. The aim of this article was to determine whether differences in clinical presentation and management exist for patients with IIH between different regions the world. METHODS Retrospective database analysis of adult patients with IIH from 4 different neuro-ophthalmology clinics. The data collected included gender, age of onset, body mass index (BMI), lumbar puncture opening pressure, initial visual acuity (VA), initial visual field (VF) mean deviation (MD), pharmacological or surgical treatment, length of follow-up, final VA, and final VF MD. RESULTS The study population consisted of 244 patients, with significant regional variations of female to male ratio. Overall, there was no significant difference regarding the age of diagnosis or the BMI. Acetazolamide was the first line of treatment in all groups but there was a difference between countries regarding second-line treatment, including the use of surgical interventions. Mean initial VA differed between groups but the final change in VA was the same among all the study groups. CONCLUSIONS There are differences in IIH presentation, treatment, and response to therapy among different countries. International prospective studies involving multiple centers are needed to determine the potential influence of environmental and genetic factors on the development of IIH and to improve the management of this potentially blinding disorder.