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  • Features of ONH Prelaminar Schisis in Advanced Glaucoma

    By Lynda Seminara
    Selected by Richard K. Parrish II, MD
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    Journal Highlights

    American Journal of Ophthalmology, December 2021

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    Spectral-domain OCT allows detailed visualization of the optic nerve head (ONH) and commonly detects prelam­inar schisis, which often presents as splitting of the superficial prelaminar tissue and floating of retinal vessels. Although the schisis may result from complex interactions between mechan­ical forces induced by glaucomatous cupping and glial cell–induced physio­logic disturbances in prelaminar tissue, the precise mechanisms by which it develops are unknown. Sung et al. ana­lyzed cross-sectional scans of the ONH in eyes with advanced glaucoma with the aim of identifying features of ONH prelaminar schisis and factors related to it. They found associations with thin and deep lamina cribrosa (LC), short axial length, and thick macula.

    For this retrospective study, the researchers included 116 patients (116 eyes) with advanced glaucoma who underwent comprehensive ophthalmic examinations, including SD-OCT. ONH prelaminar schisis was identified independently by two evaluators, and consensus was required to deem it present. Also documented were Bruch membrane opening–minimum rim width (BMO-MRW), thickness and depth of the LC, and thickness of the peripapillary retinal nerve fiber layer (RNFL) and the macula (total retinal thickness, RNFL, ganglion cell layer, inner plexiform layer). Peripapillary and subfoveal choroidal thickness was noted. Findings were compared for pa­tients with and without ONH prelami­nar schisis.

    The investigators found ONH prelaminar schisis in 48 eyes (41.4%). It was more common in those patients who were older (p < .001) or had a shorter axial length (p < .001) or a thinner or deeper LC (p = .004 and .014, respectively). It also was linked to greater thickness of the macular ganglion cell layer (p =.001), the inner plexiform layer (p = .001), and the macula overall (p < .001). With ONH prelaminar schisis, macular structural parameters tended to coincide better with functional parameters than did BMO-MRW and peripapillary RNFL thickness.

    Such findings may have implications for managing advanced glaucoma with or without ONH prelaminar schisis, the authors said. They recommend similar explorations in mild and mod­erate glaucoma, as well as research to determine the temporal relationship between ONH prelaminar schisis and key parameters.

    The original article can be found here.