Prelaminar Neuronal Tissue Thickness May Be the Solution

This paper develops a new structural tool by enhanced depth imaging-optical coherence tomography (EDI-OCT) that enhances diagnosis of optic neuronal integrity in cases of anatomically disturbed optic nerve head. A prospective observational cross-sectional study included 66 subjects (66 eyes), 32 normal optic nerve head (group A), and 34 abnormal optic nerve head (group B), chosen from Al-Azhar University Hospitals and charity eye centre (El-Mustafa Eye Centre), from August 2022 to December 2022. They were investigated by perimetry, circumpapillary retinal nerve fiber (cpRNFL) scan, and enhanced depth imaging of optic nerve head scan by the spectralis OCT. The cpRNFL thickness was automatically segmented and calculated, while pre-laminar neuronal tissue thickness in enhanced depth images was segmented and calculated manually by built-in calibre software in spectralis OCT. There were a highly statistically significant positive correlation between Global circumpapillary RNFL thickness (94.94±17.91 um) and Prelaminar neuronal tissue thickness (96.19±18.06 um), with (r=0.978 and p < 0.001); in normal optic nerve head group. There is no statistically significant negative correlation between Global circumpapillary RNFL thickness (102.88±19.90 um) and Prelaminar neuronal tissue thickness (91.53±22.83 um), with (r-0.241 and p>0.05); in abnormal optic nerve head group. A new EDI-OCT tool can extend our ability to measure prelaminar neuronal tissue thickness instead of cpRNFLT, for diagnosis and follow up for any neuropathy in abnormal ONH.