The Application Of Optical Coherence Tomography In Nonarteritic Anterior Ischemic Optic Neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) is a clinialcommon neuropathy characterized by optic edema and visual field defects. Inrecent years，with the wide application of Optical coherence tomography(OCT) in NAION，we have more profound understanding about this disease.NAION and papillitis (PA) have many similarities in clinical manifestations，so it is difficult to identify the two kind of disease by ophthalmoscope、visualfield and fundus fluorescein angiography (FFA) which are commonly used inclinical. At present，the research on OCT in NAION focused mainly on opticdisk，we found macula serous neuroepithelial detachment (MSND) in NAIONduring acute phase. To our knowledge，no study finding NSND in NAIONwas published by now. To compare the OCT characteristics of optic diskedema state between NAION and PA patients，to investigate the cause andcharacteristics of MSND in NAION，in order to enhance the comprehensiveunderstanding of NAION，provide basis for differential diagnosis and furthertreatment.Part I Macular serous neuroepithelial detachment in nonarteriticanterior ischemic optic neuropathyObjective：To investigate the cause and characteristics of MSND inNAION，in order to enhance the comprehensive understanding of NAION andprovide basis for further treatment.Methods：120eyes of119NAION patients in the acute phase underwentcomplete ophthalmic examination，including best corrected visual acuity，visual field，FFA and OCT of the optic disc and macula. All of themunderwent colour fundus photograph and OCT examination during each of thefollow-up process.Results：Of all the NAION patients，20eyes of19patients (16.7%) accompanied with MSND. Ophthalmoscopy showed the normal or mildedematous macula，and FFA didn’t show abnormal fluorescein leaking fromthe retinal or choroidal blood vessels. There were3types of undermacularfluid location on OCT images: fluid limited under the macular region，didn’tconnect to the edematous optic disc，and without retinal edema between themacula and optic disc in8eyes. Fluid limited under the macular region，didn’tconnect to the edematous optic disc，and with the cystoid edema in the retinalinterlayer between the optic disc and macula in7eyes. Fluid located betweenthe optic disc and macula in5eyes. There were no significant differencebetween eyes with and without MSND in NAION duration，attacked time（p=0.179）and visual field mean sensitivity(t=-1.221，p=0.225).The bestcorrected visual acuity in MSND eyes were significantly poor than the othereyes without MSND (p=0.038). The highest and mean height of theedematous optic disc in MSND eyes were significantly higher than the othereyes without MSND (P＜0.05). Fluid underlying the macula disappeared withthe edematous resolution in the optic disc，and14eyes left hard exudates inthe macula region.Conclusion：NAION in acute phase can be associated with macularneuroepithelial detachment，its occurrence is due to severe optic disc edema.The undermacular fluid probably arised from the edematous optic disc.Part II The comparison of OCT characteristics of optic disc edema statebetween acute NAION and PAObjective：To compare the OCT characteristics of optic disc edema statebetween NAION and PA patients，in order to provide a basis for differentialdiagnosis.Methods：24PA patients30eyes and30NAION patients30eyesunderwent complete ophthalmic examination at their first visit，includingvisual field，FFA and OCT of the optic disc.Results：The value of the optic disc highest poin（tt=-3.486，p=0.001）、the mean value of superior(t=-3.044，p=0.004)、nasal(t=-2.444，p=0.018、temporal optic disc(t=-3.211，p=0.002) and in the central disc within a1mm (p=0.028)、3mm diameter circle(p=0.005) of NAION eyes were significantlyhigher than PA eyes. The mean value of inferior optic disc（p=0.117）ofNAION eyes was also higher than PA eyes，but did not reach statisticalsignificance difference. There were significant difference between NAIONeyes and PA eyes in the shape of optic disc edema（p=0.000），Type“O”wasmain in NAION，Type“C”in PA. The range of optic disc edema weresignificantly different（p=0.002），NAION group was wider than PA group.Conclusion：NAION group and PA group are statistically significant inthe edema height、shape and range of the edematous optic disc. To comparethe OCT characteristics of optic disk edema state between NAION and PApatients have important differential diagnosis value.