Retinal function in infants with optic nerve hypoplasia: electroretinograms to large patterns and photopic flash

Area of Science:

• Ophthalmology
• Neuroscience
• Physiology

Background:

• Optic nerve hypoplasia (ONH) is a congenital condition characterized by a deficiency of retinal ganglion cells.
• ONH can affect more distal retinal layers, impacting overall retinal function.
• Electrophysiological assessment using electroretinograms (ERGs) is crucial for evaluating retinal function in ONH.

Purpose of the Study:

• To investigate the electrophysiological function of the retina in patients with ONH using ERGs.
• To determine the correlation between the severity of ONH and retinal function as measured by ERGs.
• To explore the association between clinical signs, such as tortuous retinal vessels, and retinal dysfunction in ONH.

Main Methods:

• ERGs, including pattern reversal and photopic flash stimuli, were recorded from 48 subjects with ONH (3.5-35 months).
• Fundus photography was used to quantify ONH severity (disk diameter/disk macula ratio) and identify clinical signs like tortuous vessels.
• Eyes were categorized into moderate or severe ONH based on established criteria.

Main Results:

• Pattern ERGs were detectable in 80% of ONH eyes, with good quality photopic flash ERGs in all eyes.
• ONH severity correlated significantly with the amplitude of photopic flash b-waves and pattern ERG N95 component (P<0.01).
• Tortuous retinal vessels were associated with reduced photopic b-wave amplitude and diminished or undetectable pattern ERGs.

Conclusions:

• Retinal dysfunction distal to ganglion cells is common in ONH but not solely predictable by ONH severity.
• Tortuous retinal vessels in ONH may serve as a clinical indicator of associated retinal dysfunction.
• ERG assessments provide valuable insights into the extent of retinal involvement in ONH.