Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Regulation of Water Output01:26

Regulation of Water Output

844
The human body predominantly expels water through the urinary system. On average, an individual generates around 1.5 liters of urine each day. This amount can fluctuate based on how well a person is hydrated, but a critical minimum quantity of urine must be produced to ensure the body's proper functioning. Daily, the kidneys remove 600 to 1200 milliosmoles of dissolved substances, effectively excreting excess minerals and water-soluble toxins such as creatinine, urea, and uric acid from the...
844
Physiology of Urine Formation01:24

Physiology of Urine Formation

6.1K
Urine formation is an essential function of the human body. It plays a critical role in maintaining homeostasis by regulating the volume and composition of body fluids. The kidneys, the primary organs involved in this process, filter blood to remove waste products and excess substances, ultimately producing urine.
Glomerular Filtration
The first stage in urine formation is glomerular filtration. Each kidney contains approximately 1 million nephrons, the functional units of filtration, with a...
6.1K
Testing a Claim about Mean: Unknown Population SD01:21

Testing a Claim about Mean: Unknown Population SD

3.6K
A complete procedure of testing a hypothesis about a population mean when the population standard deviation is unknown is explained here.
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used;...
3.6K
Regulation of Water Intake01:25

Regulation of Water Intake

1.1K
Osmolality refers to the number of solute particles per kilogram of solvent in a solution. Plasma osmolality specifically indicates the total number of solute particles per kilogram of water in blood plasma. This value reflects the body's hydration status and is tightly regulated through mechanisms controlling water intake and output. While water consumption is a conscious decision, the body has intrinsic regulatory systems to maintain fluid balance. Dehydration, a state of water deficit...
1.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Randomized comparison of lipid-containing and non-lipid-containing artificial tears on tear film dynamics over a 3-month period.

Optometry and vision science : official publication of the American Academy of Optometry·2026
Same author

Helminth infection induces RELMα-dependent adipose tissue transcriptional reprogramming and protection against diet-induced obesity.

bioRxiv : the preprint server for biology·2026
Same author

Up to Date Status and Acceptance of the Influenza Vaccine among a National Sample of Emergency Department Patients.

The Journal of emergency medicine·2026
Same author

The Feasibility of a Dietary and Lifestyle Behaviour Change Intervention among Low-income Latinas and Indigenous Mexicans in Rural Desert Communities: A Pilot Randomized Controlled Trial.

Public health nutrition·2026
Same author

Rates of premature ovarian insufficiency and surgical menopause in patients with endometriosis.

Journal of gynecology obstetrics and human reproduction·2026
Same author

Advanced in vitro cardiac models for drug evaluation: integration of organoids, engineered tissues, and microphysiological systems.

Microsystems & nanoengineering·2026

Related Experiment Video

Updated: Sep 9, 2025

Author Spotlight: Isolating Biomolecules from Mouse Tears — A Methodology for Molecular Analysis and Biomarker Research
09:04

Author Spotlight: Isolating Biomolecules from Mouse Tears — A Methodology for Molecular Analysis and Biomarker Research

Published on: July 19, 2024

1.8K

Diurnal Variability of Human Tear Volume and Production Rate: An Exploratory Study.

Dorothy K Ma1,2, Yameng Ge3, Alisa K Molina2

  • 1Vision Science Group, Herbert Wertheim School of Optometry and Vision Science, University of California - Berkeley, Berkeley, CA, USA.

Translational Vision Science & Technology
|September 2, 2025
PubMed
Summary

This study reveals that tear aqueous production rate and modified Schirmer strip test wetted length show distinct diurnal patterns, unlike tear meniscus height and traditional Schirmer strip test wetted length.

More Related Videos

Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation
06:29

Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation

Published on: May 2, 2020

3.9K
Bead Based Multiplex Assay for Analysis of Tear Cytokine Profiles
09:22

Bead Based Multiplex Assay for Analysis of Tear Cytokine Profiles

Published on: October 13, 2017

12.0K

Related Experiment Videos

Last Updated: Sep 9, 2025

Author Spotlight: Isolating Biomolecules from Mouse Tears — A Methodology for Molecular Analysis and Biomarker Research
09:04

Author Spotlight: Isolating Biomolecules from Mouse Tears — A Methodology for Molecular Analysis and Biomarker Research

Published on: July 19, 2024

1.8K
Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation
06:29

Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation

Published on: May 2, 2020

3.9K
Bead Based Multiplex Assay for Analysis of Tear Cytokine Profiles
09:22

Bead Based Multiplex Assay for Analysis of Tear Cytokine Profiles

Published on: October 13, 2017

12.0K

Area of Science:

  • Ophthalmology
  • Tear Film Dynamics
  • Ocular Surface Disease

Background:

  • Understanding diurnal variations in tear film parameters is crucial for diagnosing and managing dry eye disease.
  • Conventional methods for assessing tear production have limitations in accurately reflecting physiological changes throughout the day.

Purpose of the Study:

  • To compare the diurnal patterns of tear meniscus height (TMH), traditional Schirmer strip test (TSST) wetted length, modified Schirmer strip test (MSST) wetted length, and tear aqueous production (TAP) rate.
  • To investigate the reliability of different tear assessment methods across a typical diurnal cycle.

Main Methods:

  • 114 subjects were evaluated between 7:00 and 16:00 hours.
  • Tear meniscus height (TMH) measured using Oculus Keratograph 5M.
  • Traditional Schirmer strip test (TSST) and modified Schirmer strip test (MSST) wetted lengths, along with tear aqueous production (TAP) rate, were measured with and without topical anesthetic and strip sheathing.
  • Diurnal patterns analyzed using linear mixed models, adjusting for demographic and clinical factors.

Main Results:

  • Tear meniscus height (TMH) and traditional Schirmer strip test (TSST) wetted lengths remained relatively stable throughout the day (P > 0.05).
  • Modified Schirmer strip test (MSST) wetted length significantly increased between 13:00-15:00 hours (adjusted mean change 3.75-3.97 mm, P = 0.04).
  • Tear aqueous production (TAP) rate also significantly increased between 13:00-14:00 hours (adjusted mean change 0.63 µL/min, P = 0.04).

Conclusions:

  • A distinct diurnal pattern was observed in tear aqueous production rate (TAP) and modified Schirmer strip test (MSST) wetted length.
  • Tear meniscus height (TMH) and traditional Schirmer strip test (TSST) wetted length are less sensitive to diurnal variations in tear production.
  • The study highlights the limitations of TMH and TSST for evaluating tear production, suggesting TAP rate offers more valuable insights.