Purpose:
Non-arteritic ischemic optic neuropathy (NAION) involves specificzones of ischemic injury. This study aimed to analyze the patternof ganglion cell and nerve fiber layer (NFL) loss by opticalcoherence tomography (OCT).
Methods:
.Patients diagnosed with NAION from 2007 to 2009 were categorizedinto three groups- ‘superior field loss (SFL)’,‘inferior field loss (IFL)’, and ‘bihemisphericloss (BFL)’. They were scanned on RTVue Fourier-domainOCT six months after presentation. Macular GCC and peripapillaryNFL thickness maps were computed from OCT scans. Normal referencedata was obtained from the Advance Image for Glaucoma Study(www.AIGStudy.net). The correlation between the superior-inferiordifference (SID) of GCC or NFL loss and SID of VF was calculatedusing linear regression.
Results:
Twenty five NAION eyes with valid VF and OCT measurements wereanalyzed for NFL and GCC thickness in both hemispheres (table).The SID of VF loss significantly correlated to the SID of NFL(R2=0.68) and GCC loss (R2=0.58). The average NFL deviationmap of SFL cases showed infratemporal NFL loss while the IFLcases showed three quadrants of NFL loss from superotemporalto inferonasal quadrants (fig).
Conclusions:
Altitudinal VF loss in NAION corresponds to characteristic patternsof NFL and GCC loss in the opposite hemisphere. IFL cases generallyshowed larger damage areas than SFL cases on OCT. Recognizingthese patterns may aid in the diagnosis and evaluation of NAIONwith OCT.
Keywords: imaging/image analysis: clinical • nerve fiber layer • optic nerve