The Effects of Mydriatic Eye Drops in Retinopathy of Prematurity Examinations

The Effects of Mydriatic Eye Drops on Cerebral Blood Flow and Oxygenation in Retinopathy of Prematurity Examinations: A Prospective Observational Trial

Retinopathy of prematurity (ROP) is a retinal disorder of preterm neonates and a potential cause of blindness. As early diagnosis and treatment preserve vision, very low birth weight infants must be screened for ROP. Mydriatic eye drop administration is essential to perform funduscopic evaluations. The most commonly used mydriatic drops for pupil dilatation are 0.5-1.0% tropicamide and/or 0.5-1.0% phenylephrine or 0.2-1.0% cyclopentolate. Phenylephrine, an alpha-1 sympathomimetic agonist, is readily absorbed from conjunctival mucosa and has a potent systemic vasopressor effect. Tropicamide causes cycloplegia by inhibition of ciliary muscle contraction and has a short acting para-sympatholytic effect.

Systemic absorption of mydriatic eye drops has been associated with cardiovascular, respiratory and gastrointestinal adverse effects. Systemic side effects include apnea, desaturation, increased heart rate and blood pressure, delayed gastric emptying, and feeding intolerance. The data about the effects of mydriatics on cerebral blood flow and tissue oxygenation are sparse. Cerebral blood flow autoregulation depends in part on the adrenergic and cholinergic control of cerebral vasculature, but whether mydriatics have an effect on cerebral haemodynamics is unknown. Near-infrared spectroscopy and Doppler ultrasonography (US) are non-invasive methods commonly used for neuromonitorization in NICUs. The regional blood flow changes measured using Doppler US have been reported to be associated with cerebral oxygenation and indicate a high correlation with NIRS in newborns.

The aim of this study was to evaluate the effects of mydriatic eye drops on cerebral oxygenation and blood flow in preterm infants by NIRS and Doppler US.

Inclusion Criteria:

• Babies born at gestational age less than 34 weeks and/or birth weight below 2000 grams.

Infants undergoing their first retinopathy examination.

Exclusion Criteria:

• Congenital anomaly

  • Continued mechanical ventilation support
  • Having pain from a different cause and/or requiring concurrent analgesic use
  • Sedation analgesia administered within the last 24 hours
  • Hemodynamically unstable
  • Intraventricular hemorrhage, neurological dysfunction
  • Receiving anticonvulsant therapy.