Increment Threshold Functions in Retinopathy of Prematurity

Invest Ophthalmol Vis Sci. 2016 May 1;57(6):2421-7. doi: 10.1167/iovs.16-19294.


Purpose: To assess scotopic background adaptation in subjects with a history of preterm birth and retinopathy of prematurity (ROP). Retinopathy of prematurity is known to have long-term effects on rod photoreceptor and rod mediated postreceptor retinal function.

Methods: Rod-mediated thresholds for detection of 3° diameter, 50 ms stimuli presented 20° from fixation were measured using a spatial forced choice method in 36 subjects (aged 9-17 years) with a history of preterm birth and 11 age similar term-born subjects. Thresholds were measured first in the dark-adapted condition and then in the presence of 6 steady background lights (-2.8 to +2.0 log scot td). A model of the increment threshold function was fit to each subject's thresholds to estimate the dark-adapted threshold (TDA) and the Eigengrau (A0, the background that elevates threshold 0.3 log unit above TDA).

Results: In subjects with a history of severe ROP, both TDA and A0 were significantly elevated relative to those in former preterms who never had ROP and term-born control subjects. Subjects who had mild ROP had normal TDA but elevated A0. Neither TDA nor A0 differed significantly between former preterms who never had ROP and term-born controls.

Conclusions: The results suggest that in severe ROP, threshold is affected at a preadaptation site, possibly the rod outer segment. In mild ROP, changes in the Eigengrau may reflect increased intrinsic noise in the photoreceptor or postreceptor circuitry or both.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Child
  • Dark Adaptation
  • Disease Progression
  • Electroretinography / methods
  • Female
  • Gestational Age
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Photic Stimulation
  • Retina / physiopathology*
  • Retinal Rod Photoreceptor Cells / physiology*
  • Retinopathy of Prematurity / physiopathology*
  • Sensory Thresholds / physiology*