The Effects of Mydriatic Eye Drops in Retinopathy of Prematurity Examinations
Condition: Retinopathy of Prematurity; Mydriasis; Neonatal Disease; Analgesic Adverse Reaction
MeSH terms: Retinal Diseases; Retinopathy of Prematurity; Mydriasis; Premature Birth; Infant, Newborn, Diseases
Study type: Observational

Summary: 
      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.
    


Intervention name(s): NIRS(INVOS 5100; Covidien Somanetics, Troy, MI
Intervention type(s): Device
Intervention description(s): NIRS (Near Infrared Spectroscopy) is a non-invasive, bedside device that measures the concentration of oxygenated and deoxygenated hemoglobin in tissue, providing information about tissue oxygenation. Its working mechanism is based on the ability of light with wavelengths between 700-1000 nm to penetrate up to 8 cm into the skin and brain tissue. It offers continuous information about tissue oxygenation in different regions using probes attached to the skin. While pulse oximeters indicate arterial oxygen saturation, they are insufficient in detecting tissue-level hypoxia. Therefore, NIRS, being a painless method, is frequently used in the monitoring of newborns in the intensive care unit.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Sixty two infants with a gestational age below 34 weeks and/or with a birth weight of less
        than 2000 g. were included in the study. The infants who underwent the initial retinopathy
        screening exam and did not need any respiratory support at the time of the examination were
        included. The neonates with congenital anomaly, sepsis, hemodynamic instability and
        intraventricular hemorrhage were excluded.
      
Keywords: Cerebral blood flow; Cerebral oxygenation; Mydriatic eye drops; Doppler ultrasonography; Retinopathy of prematurity; NIRS; Neonate