Inner retinal layer thinning in Parkinson disease.

OBJECTIVE: To quantify retinal thickness in patients with Parkinson disease (PD). METHODS: Forty-five eyes of 24 PD patients and 31 eyes of 17 control subjects underwent a comprehensive ophthalmologic examination. We used optical coherence tomography to examine retinal thickness, separately quantifying the inner and outer retinal layers. Intraocular pressure was measured by Goldmann applanation tonometry. RESULTS: The mean (SD) ages of the patients with PD and healthy subjects were 64.0 (6.5) years vs 63.5 (10.7) years (P = .77). The mean (SD) intraocular pressure was 13.6 (+/-2.7) mm Hg in the PD patients. No difference was found in either the superior or inferior outer retinal layer thickness of PD vs control eyes. The mean (SD) superior inner retinal layer thickness of PD vs control eyes was 88.79 (11.3) microm vs 103.5 (24.3) microm (P = .01), and the mean inferior inner retinal layer thickness was 89.83 (11.1) microm vs 104.0 (23.5) microm (P = .01). CONCLUSIONS: The inner retinal layer is significantly thinner in PD patients than in healthy subjects. Idiopathic PD, distinct from glaucoma, needs to be considered in the differential diagnosis of retinal nerve fiber layer thinning.

Circadian rhythm dysfunction in glaucoma: A hypothesis.

The absence of circadian zeitgebers in the social environment causes circadian misalignment, which is often associated with sleep disturbances. Circadian misalignment, defined as a mismatch between the sleep-wake cycle and the timing of the circadian system, can occur either because of inadequate exposure to the light-dark cycle, the most important synchronizer of the circadian system, or reduction in light transmission resulting from ophthalmic diseases (e.g., senile miosis, cataract, diabetic retinopathy, macular degeneration, retinitis pigmentosa, and glaucoma). We propose that glaucoma may be the primary ocular disease that directly compromises photic input to the circadian time-keeping system because of inherent ganglion cell death. Glaucomatous damage to the ganglion cell layer might be particularly harmful to melanopsin. According to histologic and circadian data, a subset of intrinsically photoresponsive retinal ganglion cells, expressing melanopsin and cryptochromes, entrain the endogenous circadian system via transduction of photic input to the thalamus, projecting either to the suprachiasmatic nucleus or the lateral geniculate nucleus. Glaucoma provides a unique opportunity to explore whether in fact light transmission to the circadian system is compromised as a result of ganglion cell loss.

Daily illumination exposure and melatonin: influence of ophthalmic dysfunction and sleep duration.

BACKGROUND: Ocular pathology lessens light's efficacy to maintain optimal circadian entrainment. We examined whether ophthalmic dysfunction explains unique variance in melatonin excretion of older adults over and above the variance explained by daily illumination, medical, and sociodemographic factors. We also examined whether ophthalmic dysfunction influences relationships between ambient illumination and melatonin. METHODS: Thirty older adults (mean age = 69 years; Blacks = 42% and Whites = 58%) of both genders participated in the study. Demographic and health data were collected at baseline. Participants underwent eye exams at SUNY Downstate Medical Center, wore an actigraph to monitor illumination and sleep, and collected urine specimens to estimate aMT6s concentrations. RESULTS: Hierarchical regression analysis showed that illumination factors explained 29% of the variance in aMT6s mesor. The proportion of variance explained by ophthalmic factors, sleep duration, and race was 10%, 2%, and 2%, respectively. Illumination factors explained 19% of the variance in aMT6s acrophase. The proportion of variance explained by ophthalmic factors, sleep duration, and race was 11%; 17%; and 2%, respectively. Controlling for sleep duration and race reduced the correlations between illumination and melatonin, whereas controlling for ophthalmic factors did not. CONCLUSION: Ophthalmic exams showed that elevated intraocular pressure and large cup-to-disk ratios were independently associated with earlier melatonin timing. Lower illumination exposure also had independent associations with earlier melatonin timing. Conceivably, ophthalmic and illumination factors might have an additive effect on the timing of melatonin excretion, which in turn might predispose individuals to experience early morning awakenings.

Sleep complaints and visual impairment among older Americans: a community-based study.

BACKGROUND: This report describes the associations between sleep complaints and reported visual impairment in an urban community-residing older adult sample. METHODS: A total of 1118 volunteers from a biracial cohort participated in the study (mean age = 74 +/- 6; mean body mass index = 28 +/- 10). Volunteers were recruited using a stratified, cluster sampling technique. In a standard order, several questionnaires were administered, soliciting information on socioeconomic status, physical health, social support, and emotional experience. The physical health questionnaire included questions on whether or not the volunteer experienced sleep disorder, visual impairment, heart disease, respiratory disease, arthritis, and hypertension. In this report, we present data on the prevalence of reported sleep problems and visual impairment among older adults. RESULTS: Of the total sample, 9% used sleep medicine, 25% reported difficulty falling asleep, 52% indicated experiencing difficulty maintaining sleep, 28% reported waking up early in the morning, and 12% reported daytime sleep longer than 2 hours. Chi-square results showed greater sleep complaints for volunteers with visual impairment. Consistent with these results, analysis of variance revealed that visually impaired volunteers had a higher index rate of sleep disturbance (F((1, 1110)) = 35.32, p <.0001). CONCLUSIONS: These data provide evidence that older adults reporting visual impairment are also likely to report sleep complaints. This verifies laboratory findings of an association of ophthalmic diseases with sleep-wake problems and with circadian rhythm abnormalities.