Fasting reduces tear production

Fasting significantly reduces the amount of tears produced by the eye and increases the osmolarity of the tears, according to new research published in Eye & Contact Lens: Science & Clinical Practice. Fasting does not deteriorate the parameters of corneal topography or ocular aberrations in people who are healthy, however.

The study authors conducted a prospective controlled study of 29 eyes in 29 healthy men (mean age, 27.8 ± 5.9 years; range, 20 to 47 years). All of the men underwent corneal topography via a placido disc corneal topography and aberrometry device (OPD-Scan II, Nidek) before their ophthalmic examinations. Researchers used an osmometer (OcuSense, Tear Lab) to measure tear osmolarity. They also evaluated ocular surface disease index (OSDI) scores, tear break-up time (BUT), Schirmer I test and lissamine green staining.

The investigators took measurements between 4 pm and 5 pm before and during Ramadan and compared them using paired sample t test, considering a P value of less than 0.05 as statistically significant.

The researchers found:

• The mean tear osmolarity values were 285.6 ± 8.2 mOsm/L in nonfasting periods and 293.3 ± 16.0 mOsm/L in fasting periods.
• The mean Schirmer I values were 14.8 ± 6.0 mm in nonfasting periods and 10.6 ± 5.3 mm in fasting periods.
• Tear osmolarity, OSDI and Oxford grading scores significantly increased during the fasting period compared with the nonfasting period.
• Schirmer I values and IOP decreased during the fasting period compared with the nonfasting period.
• No significant differences occurred in tear BUT, keratometry values and corneal aberration measurements in nonfasting periods compared with fasting periods.

To read an abstract of the study, click here.