Davanian is a currently completing his fellowship in glaucoma at Vanderbilt University Medical Center. His research involves studying the structural effects of sleep apnea on optic nerve and retinal vasculature.
This article appeared in the January issue of Gleams. Was this helpful? Yes No. Watch this video for tips and advice from glaucoma specialist Terri Pickering, MD. Read more ». Where the Money Goes. More information ». Like Us on Facebook. We appreciate support from corporations who believe in our mission to educate glaucoma patients and speed a cure.
Jasien JV, et al. Jorge J, et al. J Glaucoma. Mosaed S, et al. Am J Ophthalmol. Healio News Optometry Glaucoma. Biography: Rett is chief of optometry for the Greater Boston VA Healthcare system, where he teaches students and residents of optometry.
Read next. March 28, Receive an email when new articles are posted on. Please provide your email address to receive an email when new articles are posted on. You've successfully added to your alerts. Get Citation Citation.
Get Permissions. In a strictly controlled laboratory environment, a consistent elevation of intraocular pressure IOP occurred at night in healthy young adults. It is well known that environmental light is the primary synchronizer for various circadian rhythms. Is the endogenous elevation of human IOP at night detectable under moderate illumination?
We collected overnight IOP data from a group of healthy young adults who received two 1-hour light exposures of moderate intensity at night. Changes in the nocturnal IOP were compared with previous results when no light exposure was applied.
The study followed the tenets of the Declaration of Helsinki and was approved by the Institutional Review Board. Twenty-five paid volunteers ages 18—25 years were recruited mainly from employees and students of our university. Informed consents were obtained after explanation of the nature and possible consequences of the study. Experimental subjects were nonsmoking, healthy individuals with a mean age of They were selected on the basis of having a regular daily sleep cycle close to to Myopes with greater than 4 diopters were excluded.
Each subject had a complete ophthalmic examination demonstrating absence of any eye disease. None of them had a narrow iridocorneal angle under slit lamp examination. Daytime sitting IOP levels measured by the Goldmann tonometer were in the range of 11 to 18 mm Hg Before the laboratory study, subjects were instructed to maintain a daily 8-hour accustomed sleep period lights off for 7 days to enhance circadian entrainment.
Subjects wore a wrist device Actillume; Ambulatory Monitoring Inc. They were told to abstain from alcohol and caffeine for 3 days and not wear contact lenses for 24 hours. Subjects reported to the laboratory before and stayed indoors for the entire recording session.
Light—dark conditions in each sleep room were strictly controlled. Light intensity from cool-white fluorescent lights was held constant at to lux at eye level when standing. When subjects were in bed lying face-up, light intensity at eye level was at to lux in the vertical direction.
The room was absolutely dark when lights were off. Times for IOP measurements were individualized accordingly. For presentation, clock times were normalized as if each subject had an assigned sleep period from to The subjects were instructed to lie down in bed for 5 minutes before IOP measurement. One or two drops of 0.
A hard-copy record was produced for each IOP measurement. Before the assigned sleep period, measurements of IOP were taken at , , and Subjects continued their normal indoor activities.
No naps were allowed. Food and water were always available. Meal times were not regulated. Room activities were continuously videotaped using infrared cameras. Subjects went to bed just before the scheduled lights-off at Sleep was encouraged.
During the 8-hour assigned sleep period, IOP was measured at , , , and For the first two IOP measurements, subjects were awakened, if necessary, and measurements were taken in near-total darkness. One hour before the IOP measurements at and , lights were turned on by the researchers from outside the room.
Subjects were not deliberately awakened. Young Rok Lee, Michael S. Subgroup analysis was also performed, with groups defined by the time of maximum habitual-position IOP. Analysis of the entire population indicated a nocturnal peak acrophase for habitual-position IOP. Subgroup analysis indicated that 28 Subgroup analysis indicated three distinct daily patterns of peak IOP in the patients.
There was no relationship between nocturnal elevation of habitual IOP and the magnitude of VF damage. Purchase this article with an account. Jump To Patients and Methods Results Discussion References. Young Rok Lee ; Michael S.
Corresponding author: Michael S. Alerts User Alerts. You will receive an email whenever this article is corrected, updated, or cited in the literature.
You can manage this and all other alerts in My Account. This feature is available to authenticated users only. Get Citation Citation. Get Permissions. Elevated intraocular pressure IOP is the primary risk factor for the onset and progression of glaucoma, and lowering of IOP is the only method that slows the progression of the disease. Similar to other biological parameters, IOP varies over the course of a day.
Previous studies have reported that the diurnal variation in IOP is larger in glaucomatous subjects and that a larger diurnal variation is an independent risk factor for progression of glaucoma.
Currently, there is no agreement on the time of day when the maximum IOP occurs, particularly in patients with glaucoma. In a study of normotensive and hypertensive subjects, Kitazawa and Horie 3 analyzed IOP measured with a Goldmann applanation tonometer [GAT] every hour for 24 hours and reported that IOP was typically highest during the day and lowest early in the morning in both groups of patients.
However, Sacca et al. The reasons for these conflicting results may be differences in measurement techniques, in study populations, or in body positions during IOP measurements. Similarly, based on pneumotonometry, Liu et al. Subsequently, it has been suggested that nocturnal IOP elevation occurring in the supine position may play an important role in damaging the optic nerve and visual field VF in OAG patients.
With this notion in mind, we measured the time course of IOP changes in a large group of subjects who were newly diagnosed with NTG. All patients had been newly diagnosed with NTG on the basis of clinical evaluations and VF examinations at our glaucoma clinic and underwent in-hospital hour monitoring of IOP when eligible for the study.
All eligible NTG patients had optic nerves that appeared to be glaucomatous based on diffuse or focal neural rim thinning, disc hemorrhage, enlarged vertical cupping greater than 0. Patients were excluded if one or more of the following were present: untreated IOPs recorded during normal clinic hours at 8 AM, 12 PM, and 4 PM during the same day greater than 21 mm Hg in at least one eye based on GAT; evidence of intracranial or otolaryngological lesion; history of massive hemorrhage or hemodynamic crisis; previous or current use of antiglaucoma medications or systemic or topical steroids; presence of any other ophthalmic disease that could result in optic nerve and VF defects; or a history of diabetes mellitus.
Individuals who smoked or had an irregular daily sleep schedule were excluded. Finally, patients who had undergone ocular surgery or had corneal abnormalities that prevented reliable IOP measurement including refractive surgery were also excluded. All patients provided informed consent. All eligible patients in our main study were instructed to abstain from alcohol and caffeine for 3 days before hospital admission.
The diurnal and nocturnal periods may have differed among enrolled patients at home. Three measurements were taken for each eye, and the average value was used for analysis without correction for CCT in both the sitting and supine positions. The subjects were instructed to continue normal indoor activities during the diurnal period, and diurnal IOP was measured when the patients were seated. During the nocturnal period, lights in individual rooms were turned off by the nurse, and the patients were instructed to sleep with the position of the head on same level as body.
They were awakened if necessary , and the IOP measurements were performed with the tonometer under dim light, with patients supine because activation of the sympathetic nervous system while changing body position at night could be nonphysiological.
After the subjects had a minute rest period in the upright position, the nocturnal IOP was measured while they were seated. Blood pressure and heart rate were measured simultaneously with the hour IOP measurements with an automated ambulatory blood pressure BP monitor device Space Laboratories Medical Inc. If both eyes were affected, the left eye was selected for analysis. The hour pattern and peak hours of habitual-position IOP were analyzed for the entire group.
Subgroup analysis was also performed on the basis of the timing of peak habitual-position IOP. A cosinor model was used to describe the pattern of the 24 hours nychthemeral IOP; this model has been shown to be useful for fitting symmetric and stationary rhythmic patterns.
0コメント