Delayed melatonin circadian timing, lower melatonin output and sleep disruptions in myopic, or short-sighted, children

Ranjay Chakraborty, Chris Seby , Hannah Scott, Victoria Tang, Eva Kemps, Nicola Anstice, Emilia Jurs, Nicole Lovato, Deepa Ajay Taranath, Richard Mills, Leon Lack

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Study Objectives
This study investigated the differences in melatonin circadian timing and output, sleep characteristics, and cognitive function in myopic and non-myopic (or emmetropic) children, aged 8–15 years.

Twenty-six myopes (refractive error [mean ± standard error mean] −2.06 ± 0.23 diopters) and 19 emmetropes (−0.06 ± 0.04 diopters), aged 11.74 ± 2.31 years were recruited. Circadian timing was assessed using salivary dim-light melatonin onset (DLMO), collected half-hourly for 7 hours, beginning 5 hours before and finishing 2 hours after individual average sleep onset in a sleep laboratory. Nocturnal melatonin output was assessed via aMT6s levels from urine voids collected from 05:30 pm to 8:00 am the following morning. Actigraphy-derived objective sleep timing were acquired for a week prior to the sleep laboratory visit. Cognitive assessments of sustained attention (using psychomotor vigilance task [PVT]) and working memory (using digit spans) were performed on the night of sleep laboratory.

Myopic children (9:07 pm ± 14 minutes) exhibited a DLMO phase-delay of 1 hour 8 minutes compared to emmetropes (7:59 pm ± 13 minutes), p = 0.002. aMT6s melatonin levels were significantly lower among myopes (18.70 ± 2.38) than emmetropes (32.35 ± 6.93, p = 0.001). Myopes also exhibited significantly delayed sleep onset, delayed wake-up time, poor and reduced sleep, and more evening-type diurnal preference than emmetropes (all p < 0.05). Finally, myopes showed a slower reaction time in the PVT (p < 0.05), but not digit span tasks at night.

These findings suggest a potential association between circadian rhythm dysfunction and myopia in children.
Original languageEnglish
Article numberzsad265
Number of pages16
Issue number1
Early online date12 Oct 2023
Publication statusPublished - 1 Jan 2024


  • melatonin
  • circadian rhythms
  • myopia
  • sleep
  • dim-light melatonin onset
  • urinary 6-sulphatoxymelatonin
  • cognition
  • refractive error
  • axial eye length


Dive into the research topics of 'Delayed melatonin circadian timing, lower melatonin output and sleep disruptions in myopic, or short-sighted, children'. Together they form a unique fingerprint.

Cite this