Abstract
Purpose:
To compare the ganglion cell layer (GCL) thickness measurements to retinal nerve fiber layer (RNFL) analysis in patients affected by ischemic optic neuropathy (ION) using high definition optical coherence tomography (HD-OCT).
Methods:
Twenty-five subjects with the diagnosis of ischemic optic neuropathy were recruited during the period August-December 2013. A second group of thirty age-matched controls was also included. Full neuro-ophthalmologic evaluation was carried-out including Cirrus HD-OCT to evaluate the GCL and RNFL thickness. Statistical analysis was done using Mann-Whitney U test to compare RNFL vs. GCL thicknesses between patients and controls.
Results:
All patients with ION showed decreased GCL thickness when compared with the control group (P<0.001). RNFL was thinner in twenty-one patients (p<0.05). In four patients with acute ischemic optic neuropathy there was GCL loss despite an increase of the RNFL thickness compared to the control group. GCL analysis showed a better correlation with the visual field defects than RNFL.
Conclusions:
GCL thickness analysis proved to be a sensitive biomarker to detect early damage of the retinal structure after an ION event. In acute cases GCL thickness is reduced earlier than RNFL, which usually showed increased thickness for several weeks after the acute event due to axonal swelling. In non-acute ION cases presenting with optic nerve pallor, GCL analysis showed an altitudinal pattern of ganglion cells loss. This HD-OCT observation can be useful in diagnosing remote ION in patients presenting with long-term visual loss, optic nerve pallor and atypical visual field defects.
Keywords: 613 neuro-ophthalmology: optic nerve •
531 ganglion cells