Optical coherence tomography angiography of optic disc perfusion in non-arteritic anterior ischemic optic neuropathy

AIM：To compare the optic disc blood flow of non-arteritic ischemic optic neuropathy（NAION）eyes with normal eyes.METHODS：The optic disc blood flow densities of diagnosed non-acute phase NAION eyes（21 eyes,14 individuals）and normal eyes（19 eyes,12 individuals）were detected via Optovue optical coherence tomography angiography（OCTA）.The optic disc blood flow was measured via Image J software.Correlations between optic disc perfusion and visual function variables were assessed by linear regression analysis.RESULTS：The average percentage of the optic disc nonperfusion areas in the non-acute phase NAION patients（17.84%±6.18%）was increased,when compared to the normal control eyes（8.61%±1.65%）,and the difference was statistically significant（P〈0.01）.Moreover,there was a proportional correlation between the visual field mean defect（MD）and the optic disc non-perfusion area percentage,and the relationship was statistically significant（t=3.65,P〈0.01,R2=0.4118）.In addition,the critical correlation between the best corrected visual acuity（BCVA）and the optic disc non-perfusion area percentage was statistically significant（t=4.32,P〈0.01,R2=0.4957）.CONCLUSION：The optic disc non-perfusion area percentages detected via OCTA in NAION eyes were significantly increased when compared with the normal eyes.Both the BCVA and MD were correlated with the optic disc flow detected,revealing that OCTA may be valuable in the diagnosis and estimation of NAION.

Lens thickness assessment : anterior segment optical coherence tomography versus A-scan ultrasonography

AIMTo assess lens thickness measurements with anterior segment-optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US).METHODSThere were 218 adult subjects (218 eyes) aged 59.2±9.2y enrolled in this prospective cross-sectional study. Forty-three eyes had open angles and 175 eyes had narrow angles. Routine ophthalmic exam was performed and nuclear opacity was graded using the Lens Opacities Classification System III (LOCS III). Lens thickness was measured by AS-OCT (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA). The highest quality image was selected for each eye and lens thickness was calculated using ImageJ software. Lens thickness was also measured by A-scan US.RESULTSInterclass correlations showed a value of 99.7% for intra-visit measurements and 95.3% for inter-visit measurements. The mean lens thickness measured by AS-OCT was not significantly different from that of A-scan US (4.861±0.404 vs 4.866±0.351 mm, P=0.74). Lens thickness values obtained from the two instruments were highly correlated overall (Pearson correlation coefficient=0.81, P<0.001), and in all LOCS III specific subgroups except in grade 5 of nuclear opacity. Bland-Altman analysis revealed a 95% limit of agreement from -0.45 to 0.46 mm. Lens thickness difference between the two instruments became smaller as the lens thickness increased and AS-OCT yielded smaller values than A-scan US in thicker lens (β=-0.29, P<0.001)CONCLUSIONAS-OCT-derived lens thickness measurement is valid and comparable to the results obtained by A-scan US. It can be used as a reliable noncontact method for measuring lens thickness in adults with or without significant cataract.

Analysis of optic disc damage by optical coherence tomography in terms of therapy in non-arteritic anterior ischemic optic neuropathy

This study aimed to assess the relationship between the rate of nerve fiber loss in non-arteritic anterior ischemic optic neuropathy（NAION） and time delay before therapy.Total 24 patients received the same treatment within or after 2wk（early and late groups）.There were significantly lower level of destruction of nerve fibers（P=0.0014） and significantly better visual field sensitivity（P=0.039） in early group.The results indicate that therapy should be started within 2wk.The degree of ischemic damage due to NAION correlates well with retinal nerve fiber layer thickness and the ischemia-induced decrease in visual field sensitivity.

Pseudophakic Malignant Glaucoma Treatment Assisted with Anterior Segment Optical Coherence Tomography: A Case Report

PSEUDOPHAKIC malignant glaucoma is diagnosedbased on the presence of a shallow or flat centraland peripheral anterior chamber in the presenceof patent iridectomy, with intraocular pressure（IOP） of 22 mm Hg or more after lens extraction andintraocular lens implantation.1 Pseudophakic malignantglaucoma is one of the most challenging complicationsfaced by surgeons. Initial medication includes topicalcycloplegics, osmotic agents.

Comparison of measurements of anterior chamber angle via anterior segment optical coherence tomography and ultrasound biomicroscopy

BACKGROUND Glaucoma is an irreversible optic neuropathy with the loss of visual field and decrease of vision.The variable clinical manifestations may result in differential diagnostic difficulties.The early screening and diagnosis of glaucoma are currently experiencing a demand for anterior segment analysis tools that can gather more information with one short measurement.Therefore,we analyzed the agreement,difference,and correlation of chamber angle parameters such as angel opening distance at 500μm(AOD500)and trabeculo-iris space area at 500μm^2(TISA500)measured by anterior segment optical coherence tomography(ASOCT)and ultrasound biomicroscopy(UBM).AIM To compare the differences,correlation,and agreement in measuring AOD500 and TISA500 by AS-OCT and UBM.METHODS Both AS-OCT and UBM were performed to measure AOD500 and TISA500 in 45 subjects(72 eyes).All subjects without glaucoma were collected from October 2015 to August 2016 at the Ophthalmology Department of the Fourth Affiliated Hospital of China Medical University.Data of the two groups(AOD500 and TISA500)were compared by nonparametric tests.Pearson correlative analysis and Bland-Altman analysis were used to compare the correlation and agreement.RESULTS There were no significant differences between AS-OCT and UBM in measuring AOD500(P1=0.110,P2=0.633,P3=0.078,and P4=0.474)and TISA500(P1=0.584,P2=0.889,P3=0.297,and P4=0.550)of the four quadrants of the anterior chamber angle.There was a high correlation in measuring AOD500(r1=0.562,r2=0.671,r3=0.635,and r4=0.720;P<0.001)and TISA500(r1=0.584,r2=0.889,r3=0.297,and r4=0.550;P<0.001).There was a good agreement in measuring AOD500 and TISA500 by the two modalities.CONCLUSION There is a high correlation and agreement between AOD500 and TISA500 measurements by AS-OCT and UBM.They are interchangeable under some circumstances.AS-OCT proves to be a better early screening tool for glaucoma.

Comparison of Anterior Segment Optical Coherence Tomography and Ultrasound Biomicroscopy for Iris Parameter Measurements in Patients with Primary Angle Closure Glaucoma

Purpose: To compare the repeatability and consistency of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) in measuring iris parameters in patients with primary angle closure glaucoma. Methods: Twenty-two patients (38 eyes) with primary angle closure glaucoma,including 5 eyes with acute angle closure glaucoma,10 fellow eyes of acute angle closure glaucoma, and 23 eyes with chronic angle closure glaucoma, were recruited consecutively in our hospital. All subjects underwent anterior scanning by AS-OCT and UBM. Peripheral iris thickness (PIT) and iris curvature (IC) in the anterior segment image obtained by AS-OCT and UBM were measured twice. The reproducibility of these two scans was evaluated by the intraclass correlation coefficient (ICC). A paired t-test was used to compare the difference between the two scans and the 95% limits of agreement (LoA) were calculated. Results:The ICCs of PIT and IC measured by UBM were 0.892 and 0.936 respectively, while for AS-OCT these values were 0.629 and 0.859, respectively. UBM had a higher reproducibility in both PIT and IC measurements as compared with AS-OCT.Differences in PIT measurement between AS-OCT and UBM(P=0.331).were not statistically significant, the 95% LoA (-0.178～0.156) mm was 36.1～41.2% of the mean. The IC was 0.053 mm smaller when measured by UBM than by AS-OCT (P=0.017), with the 95% LoA (-0.100～0.206) mm, or 36.2～74.6% of the mean.Conclusion:UBM had a higher reproducibility in measuring iris parameters than AS-OCT. The consistency between AS- OCT and UBM in measuring iris parameters was low in primary angle closure glaucoma patients. (Eye Science 2013; 28:1-6)

Anterior segment optical coherence tomography for identifying muscle status in strabismus surgery

Anterior segment optical coherence tomography （AS-OCT） finds very few indications in the domain of strabismus surgery. Current applications remain restricted to determining limbus-muscle insertion distance and anterior segment changes after strabismus surgery. We discuss two cases of operated strabismus surgery where AS-OCT imaging helped in identifying the operated eye and/or extra ocular muscles （EOM） and thus proved instrumental in planning and management.

Optical coherence tomography evaluation of retinal nerve fiber layer thickness in non-arteritic anterior ischemic optic neuropathy and primary open angle glaucoma:a systematic review and Meta-analysis

AIM:To assess the differences in average and sectoral peripapillary retinal nerve fiber layer(p RNFL)thickness using spectral domain optical coherence tomography(SD-OCT)in patients with non-arteritic anterior ischemic neuropathy(NAION)compared with those with primary open angle glaucoma(POAG).METHODS:A comprehensive literature search of the Pub Med,Cochrane Library,and Embase databases were performed prior to October,2021.Studies that compared the p RNFL thickness in NAION eyes with that in POAG eyes with matched mean deviation of the visual fields were included.The weighted mean difference(WMD)with 95%confidence interval(CI)was used to pool continuous outcomes.RESULTS:Ten cross-sectional studies(11 datasets)comprising a total of 625 eyes(278 NAION eyes,347 POAG eyes)were included in the qualitative and quantitative analyses.The pooled results demonstrated that the superior p RNFL was significantly thinner in NAION eyes than in POAG eyes(WMD=-6.40,95%CI:-12.22 to-0.58,P=0.031),whereas the inferior p RNFL was significant thinner in POAG eyes than in NAION eyes(WMD=11.10,95%CI:7.06 to 15.14,P≤0.001).No difference was noted concerning the average,nasal,and temporal p RNFL thickness(average:WMD=1.45,95%CI:-0.75 to 3.66,P=0.196;nasal:WMD=-2.12,95%CI:-4.43 to 0.19,P=0.072;temporal:WMD=-1.24,95%CI:-3.96 to 1.47,P=0.370).CONCLUSION:SD-OCT based evaluation of inferior and superior p RNFL thickness can be potentially utilized to differentiate NAION from POAG,and help to understand the different pathophysiological mechanisms between these two diseases.Further longitudinal studies and studies using eight-quadrant or clock-hour classification method are required to validate the obtained findings.

Application of Tear Meniscus Measurement by Anterior Segment Optical Coherence Tomography in the Diagnosis of Dry Eye

Dry eye,one of the most frequent ocular surface diseases, is caused by complex ocular function and mechanism disorders. Currently, no uniform standard diagnosis of dry eye has been established. Traditional clinical examinations provide inaccurate measurement and poor reproducibility due to various factors.Anterior segment optical coherence tomography (OCT) is applicable in the diagnosis of dry eye due to its high resolution, non-invasiveness, good accuracy, and repeatability.

Comparison of Intraoperative Ultrasound Pachymetry and Postoperative Optical Coherence Tomography of Anterior Segment in the Measurement of Flap Thickness in Eyes Receiving Laser in situ Keratomileusis

Purpose:To compare the measurement of flap thickness using intraoperative ultrasound pachymetry and postoperative visante anterior segment optical coherence tomography (Visante-OCT) in eyes receiving laser in situ keratomileusis (LASIK). Methods: Seventeen patients (34 eyes) received LASIK using a Technolas-217Z100 laser and AMADEUSⅡ mechanical microkeratome(140 μm head). Flap thickness was assessed with an ultrasound pachymeter intraoperatively and a Visante-OCT postoperatively at 1 week and 1 month. Results: The intraoperative mean flap thickness by ultrasound pachymetry was (124±13.9) μm (range: 96.5 to 160 μm), and mean flap thickness by Visante-OCT was (145±7.13) μm (range: 130 to 158 μm) and (143±5.32) μm (range: 132 to 155 μm) postoperatively at 1 week and 1 month respectively (F=63.52,P<0.01). Intraoperative subtraction pachymetry underestimated flap thickness compared with postoperative Visante-OCT.(P<0.01)..There was no significant difference between postoperative Visante-OCT measurements at 1 week and 1 month after LASIK.(P=0.16). The 95% limit of agreement.(LoA).of flap thickness between ultrasound Visante-OCT and pachymetry was -5.40 to 42.10 μm. Conclusion: OCT overestimates flap thickness compared with intraoperative ultrasound pachymetry when using the AMADEUSⅡ mechanical microkeratome.

Evaluation of the iridocorneal angle with accommodation using optical coherence tomography

The changes in the iridocorneal angle structure during accommodation are assessed by means of anterior segment optical coherence tomography.Thirteen right eyes were included in the study.The device used for the measurement was the Visante？omni system.The stimuli were set up at different vergences（0.0 D,-1.5 D,and-3.0 D）.The angle opening distance 500 and 750,the trabecular iris space area 500 and 750,and the scleral spur angle parameters were assessed at the nasal and temporal regions.The results in the iridotrabecular angle comparing the three accommodative states of the eye did not yield any statistically significant difference at nasal or temporal angle sections.In light of our results and in the conditions of our study,the structures of the iridocorneal angle are not significantly changed with accommodation.

Measurement of anterior chamber volume with rotating scheimpflug camera and anterior segment optical coherence tomography

Background Measurement of anterior segment parameters plays an important role in diagnosis and treatment of glaucoma. The objective of this study was to evaluate the repeatability and reproducibility of anterior chamber volume （ACV） measurements with rotating scheimpflug camera （RSC） and to examine agreement with anterior segment optical coherence tomography （AS-OCT）. Methods Thirty nine healthy normal subjects were recruited from the Eye Center of Tongren Hospital. ACV was measured using RSC and AS-OCT in a randomly selected eye for each subject. For RSC measurements, both automatic and manual ACV measurements and 2 independent operators＇ ACV measurements were obtained. All subjects were invited for 3 visits within a week to evaluate repeatability and reproducibility of ACV measurement by RSC. Agreement was evaluated between RSC and AS-OCT. Results Good repeatability and reproducibility were found for both automatic and manual ACV measurements obtained by RSC. For intrasession repeatability, coefficient of variation （CVw） and intraclass correlation coefficient （ICC） values for automatic were 3.52% and 0.98; the values for manual were 3.44% and 0.97, respectively. For intersession reproducibility, the respective CVw and ICC values were 3.96% and 0.96. Good agreement was also found in 2 operators for both automatic and manual ACV measurements; nevertheless, poor agreement was found between RSC and AS-OCT （95% confidence interval （CO for agreement of automatic RSC measurement versus AS-OCT were -96.3 to 72.8 pl and 95% CI for agreement of manual RSC measurement versus AS-OCT were between 41.7 to 10.1 #1 ）. Conclusions Both RSC automatic and manual ACV measurements showed good repeatability and reproducibility, and showed comparable agreement between 2 independent operators, but poor agreement was found between RSC and AS-OCT.

Optical coherence tomography angiography for the anterior segment

Optical coherence tomography angiography(OCTA)is a rapid and non-invasive technique for imaging vasculature in the eye.As OCTA can produce high-resolution cross-sectional images and allow depth-resolved analysis for accurate localization of pathology of interest,it has become a promising method for anterior segment imaging.Furthermore,OCTA offers a more patient-friendly alternative to the conventional invasive dye-based fluorescent angiography.However,conventional OCTA systems are typically designed and optimized for the posterior segment of the eye,and thus using OCTA for anterior segment imaging can present several difficulties and limitations.In this review,we summarized the recent developments and clinical applications in anterior segment OCTA(AS-OCTA)imaging,such as for the cornea,iris,sclera and conjunctiva.We also compared commercially available OCTA systems,discussed the limitations of adapting current OCTA technology for the anterior segment imaging,and proposed possible future directions for AS-OCTA systems.AS-OCTA provides potential for future clinical applications such as diagnosis of corneal and iris pathologies,pre-operative surgical planning,assessment of new antiangiogenic therapeutics or evaluation of limbal stem cell deficiency.With further development,OCTA for anterior segment imaging in the clinics may become common in the near future.

Post-miosis changes in the anterior chamber structures in primary and lens-induced secondary chronic angle-closure glaucoma

To evaluate post-miosis changes in the anterior chamber structures in various angle-closure glaucomas(ACG). Totally 14 eyes of primary chronic angle-closure glaucoma(PCACG), 12 eyes of lens-induced secondary chronic angleclosure glaucoma(LSACG) and 14 healthy eyes were recruited. After miosis, for PCACG group, intraocular pressure(IOP) and anterior chamber depth(ACD) changed not significantly, while anterior chamber angle widened significantly. LSACG group showed a significant increase in IOP, decrease in ACD, and narrowing in anterior chamber angle. Healthy eyes showed significant decreases in IOP and anterior chamber parameters. Thus, miosis could widen the anterior chamber angle of patients with PCACG, while increase the narrowing of anterior chamber angle and IOP of patients with LSACG. We should pay attention to the distinction between PCACG and LSACG patients and the proper administration of pilocarpine in the treatment of patients with chronic ACG.

Evaluation of dry eye disease in newly diagnosed anxiety and depression patients using anterior segment optical coherence tomography

Background:We aimed to evaluate dry eye diseases(DED)in patients with newly diagnosed depression and anxiety patients.Methods:Forty newly diagnosed depression,35 anxiety patients,and 37 controls without any history of taking psychiatric drugs(or before the beginning of psychiatric medication)and topical ophthalmic drop use,were included in the study.All depression and anxiety diagnoses were performed by an experienced psychiatrist.Beck depression and anxiety tests were used to measure disease severity.Tear film break up time(TBUT),Schirmer’s test,Oxford scores and ocular surface disease index(OSDI)were admiinistered to participants.Anterior segment optical coherence tomography was used to measure tear meniscus heights(TMH),tear meniscus depths(TMD)and tear meniscus areas(TMA).Results:In anxiety and depression groups,Schirmer’s test(mm)(7.24±6.02,6.58±4.9 and 18.79±4.9 respectively,p<0.05)and TBUT(s)(5.62±3.1,5.6±3.5 and 13.37±1.7 respectively,p<0.05)were significantly lower than control group.In addition,OSDI and Oxford scores were significantly higher than controls.OSDI scores were 28.01±19,30.43±18.49,14.38±8.14 respectively(p=0.002)and Oxford scores were 1.9±0.7,2.1±0.6 and 0.7±0.4 respectively(p=0.001).TMD,TMH and TMA values were significantly lower in anxiety and depression groups compared with control groups.Correlations between disease inventory scores and dry eye tests were detected.Conclusions:This study showed a relation between DED and newly diagnosed anxiety and depression patients with no history of psychiatric drug use.The presence of correlation between dry eye tests and disease inventory scores strengthens this association.This is an important knowledge that need to be evaluated in these patients before starting psychiatric medication.

Change of retinal nerve fiber layer thickness in patients with nonarteritic inflammatory anterior ischemic optic neuropathy

In this study, 16 patients （19 eyes） with nonarteritic anterior ischemic optic neuropathy in the acute stage （within 4 weeks） and resolving stage （after 12 weeks） were diagnosed by a series of complete ophthalmic examinations, including fundus examination, optical coherence tomography and fluorescein fundus angiography, and visual field defects were measured with standard automated perimetry. The contralateral uninvolved eyes were used as controls. The retinal nerve fiber layer thickness was determined by optical coherence tomography which showed that the mean retinal nerve fiber layer thickness and the retinal nerve fiber layer thickness from temporal, superior, nasal and inferior quadrants were significantly higher for all measurements in the acute stage than the corresponding normal values. In comparison, the retinal nerve fiber layer thickness from each optic disc quadrant was found to be significantly lower when measured at the resolving stages, than in the control group. Statistical analysis on the correlation between optic disc nerve fiber layer thickness and visual defects demonstrated a positive correlation in the acute stage and a negative correlation in the resolving stage. Our experimental findings indicate that optical coherence tomography is a useful diagnostic method for nonarteritic anterior ischemic optic neuropathy and can be used to evaluate the effect of treatment.

Assessment of anterior chamber angle changes after phacoemulsification with swept-source OCT

AIM:To assess the changes of anterior chamber angle in patients with shallow anterior chamber after phacoemulsification combined with intraocular lens(IOL)implantation,based on anterior segment swept-source optical coherence tomography(AS-SS-OCT)measurements.METHODS:This was a prospective case control study;sixty eyes of sixty case were scheduled for cataract surgery with normal intraocular pressure(IOP).Based on anterior chamber depth(ACD)and gonioscopy findings,the eyes were divided into two groups:group of shallow anterior chamber and narrow angle(SAC group,30 eyes);and group of normal anterior chamber group with wide angle(NAC group,30 eyes).Measurements of ACD,anterior chamber volume(ACV),iris volume(IV),lens vault(LV),angle opening distance(AOD),angle recess area(ARA),trabecular iris space area(TISA),and trabecular iris angle(TIA)were conducted in each group before and 3mo after surgery.RESULTS:There was no significant difference in age,axial length(AL),corneal curvature,corneal diameter,intraocular pressure,and IV between two groups before surgery,except for the LV(P=0.000).ACD and ACV were prominently larger in the NAC group than the SAC group 3mo after operation(3.69±0.38 vs 3.85±0.39 mm,P=0.025;161.37±19.47 vs 178.26±20.30 mm3,P=0.002).AOD750,ARA750 in nasal and inferior quadrants,TISA750 in all quadrants except temporal,and TIA750 in all quadrants in SAC group were significantly smaller than those in NAC group after operation(all P<0.05).CONCLUSION:Cataract surgery can deepen anterior chamber and increase the width of anterior chamber angle in Chinese subjects,but the angle related parameters including AOD750,ARA750,TISA750,TIA,TISA750,and ACV in patients with shallow anterior chamber and narrow angle do not reach the normal level.

Fast segmentation of anterior segment optical coherence tomography images using graph cut

Background:Optical coherence tomography(OCT)is a non-invasive imaging system that can be used to obtain images of the anterior segment.Automatic segmentation of these images will enable them to be used to construct patient specific biomechanical models of the human eye.These models could be used to help with treatment planning and diagnosis of patients.Methods:A novel graph cut technique using regional and shape terms was developed.It was evaluated by segmenting 39 OCT images of the anterior segment.The results of this were compared with manual segmentation and a previously reported level set segmentation technique.Three different comparison techniques were used:Dice’s similarity coefficient(DSC),mean unsigned surface positioning error(MSPE),and 95%Hausdorff distance(HD).A paired t-test was used to compare the results of different segmentation techniques.Results:When comparison with manual segmentation was performed,a mean DSC value of 0.943±0.020 was achieved,outperforming other previously published techniques.A substantial reduction in processing time was also achieved using this method.Conclusions:We have developed a new segmentation technique that is both fast and accurate.This has the potential to be used to aid diagnostics and treatment planning.

Measurement of the depths at different regions of the anterior chamber in healthy Chinese adults

AIM: To measure the depths of different regions of the anterior chamber(AC) in healthy Chinese adults, and to explore possible correlations with age or gender.METHODS: The AC was imaged by swept-source optical coherence tomography in healthy Chinese adults. The horizontal scan of the right eye was used to measure the anterior chamber depth(ACD) at 199 points.RESULTS: A total of 309 images from 309 subjects were analyzed. The ACD values at nearly all locations were negatively correlated with age(all P<0.05), except for ACD1, 2, 198, and 199(correspond to the iris roots). The mean annual decrease 0.013±0.005 mm/y for all ACDs combined, 0.008±0.004 mm/y for the peripheral region, 0.017±0.003 mm/y for the middle peripheral region, and 0.014±0.001 mm/y for the central region. The mean annual decrease was significantly different among these three regions(P<0.001). The ACD was greater in males than in females(P<0.05). The mean difference in ACD between males and females was 0.081±0.025 mm.CONCLUSION: This study showed that optical coherence tomography can be used to measure the ACD of different regions of the AC. We found reductions in ACD with age, although the reduction varied among different points, in healthy Chinese adults.

Macular ganglion cell complex injury in different stages of anterior ischemic optic neuropathy

BACKGROUND Anterior ischemic optic neuropathy(AION)is a group of ophthalmic diseases in which the optic nerve is injured causing blindness.However,the pathogenesis,clinical manifestations,and clinical treatments of AION are yet elusive.Only a few related experimental or clinical reports are available on the disease.In this study,spectral domain optical coherence tomography(SD-OCT)was used to examine the morphology of thickness swelling and atrophic changes of macular ganglion cell complex(mGCC)in the different stages of AION that were then compared with the visual fields.Thus,the clinical value of mGCC examination was alleged to be similar to that of the visual field.AIM To explore the mGCC injury at different stages in AION and the clinical significance.METHODS Cases with AION were analyzed in a retrospective study.SD-OCT was used to analyze the correlation between mGCC and peripapillary retinal nerve fiber layer thicknesses at different stages of AION and the changes in the corresponding stages of visual fields.RESULTS A total of 21 cases(28 eyes)presented AION.The onset time of AION was defined as early stage(within 3 wk of onset),middle stage(from 3 wk to 2 mo),and late stage(disease span>2 mo).In the early stage,the mGCC thickness of SD-OCT was within the normal high limit,and the perioptic nerve fibers thickness was more than the normal.The changes in the visual field in early stage were not consistent with the swelling changes in mGCC and peri-disc nerve fibers.In addition,atrophy and thinning appeared in mGCC,and the perioptic nerve fibers were swollen.However,the thickness was lower in the middle period than that in the early stage.The change in visual field was consistent with that of mGCC in this period.In the late stage,mGCC shrank and thinned,and the thickness of the nerve fibers around the optic disc in the corresponding region shrank and thinned.CONCLUSION The changes in mGCC thickness in patients with AION showed early,middle,and late stages of development by SD-OCT.Although the early stage visual field changes of AION were not consistent with the swelling changes of mGCC,the horizontal delimitation or annular atrophy of mGCC was consistent with that in the middle and late stage of the disease.The atrophy of peripheral nerve fibers was later than that of the mGCC atrophy.