Quantifying peripapillary vessel density and retinal nerve fibre layer in type 1 diabetic children without clinically detectable retinopathy using OCTA

AIM:To quantify changes in radial peripapillary capillary vessel density(ppVD)and the peripapillary retinal nerve fiber layer(pRNFL)in children with type 1 diabetes without clinical diabetic retinopathy by optical coherence tomography angiography(OCTA),providing a basis for early retinopathy in children with type 1 diabetes.METHODS:This was a retrospective study.A total of 30 patients(3–14y)with type 1 diabetes without clinical diabetic retinopathy(NDR group)were included.A total of 30 age-matched healthy subjects were included as the normal control group(CON group).The HbA1c level in the last 3mo was measured once in the NDR group.The pRNFL thickness and ppVD were automatically measured,and the mean pRNFL and ppVD were calculated in the nasal,inferior,temporal,and superior quadrants.The changes in ppVD and pRNFL in the two groups were analyzed.RESULTS:Compared with CON group,the nasal and superior ppVDs decreased in the NDR group(all P<0.01).The thickness of the nasal pRNFL decreased significantly(P<0.01),while the inferior,temporal and superior pRNFLs slightly decreased but not significant in the NDR group(all P>0.05).Person and Spearman correlation analysis of ppVD and pRNFL thickness in each quadrant of the NDR group showed a positive correlation between nasal and superior(all P<0.01),while inferior and temporal had no significant correlation(all P>0.05).There was no significant correlation between the HbA1c level and ppVD and pRNFL in any quadrant(all P>0.05).There was no significant correlation between the course of diabetes mellitus and ppVD and pRNFL in any quadrant(all P>0.05).CONCLUSION:ppVD and pRNFL decrease in eyes of children with type 1 diabetes before clinically detectable retinopathy and OCTA is helpful for early monitoring.

Clinical characteristics of peripapillary hyperreflective ovoid mass-like structures in myopic children

AIM:To describe the characteristics of peripapillary hyperreflective ovoid mass-like structure(PHOMS)in myopic children and to investigate factors associated with PHOMS.METHODS:This retrospective observational study included 101 eyes of 101 children(age≤17y)with myopia.All included patients underwent comprehensive clinical examination.Optic nerve canal parameters,including disc diameter,optic nerve head(ONH)tilt angle,and border tissue angle were measured using serial enhanced-depth imaging spectral-domain optical coherence tomography(EDI-OCT).Based on the optic disc drusen consortium’s definition of PHOMS,eyes were classified as PHOMS group and non-PHOMS group.PHOMS was categorized according to height.RESULTS:Sixty-seven(66.3%)eyes were found with PHOMS.Small PHOMS could only be detected by optical coherence tomography(OCT).Medium PHOMS could be seen with blurred optic disc borders corresponding to OCT.The most frequent location of PHOMS was at the nasosuperior(91%,61 of 67 eyes)to ONH disc.The axial length and spherical equivalent were more myopic in the PHOMS group than in the non-PHOMS group(both P<0.001).ONH tilt angle was also significantly greater in PHOMS group than in non-PHOMS group[8.90(7.16-10.54)vs 3.93(3.09-5.25),P<0.001].Border tissue angle was significantly smaller in PHOMS group than in non-PHOMS group[29.70(20.90-43.81)vs 45.62(35.18-60.45),P<0.001].In the multivariable analysis,spherical equivalent(OR=3.246,95%CI=1.209-8.718,P=0.019)and ONH tilt angle(OR=3.275,95%CI=1.422-7.542,P=0.005)were significantly correlated with PHOMS.There was no disc diameter associated with PHOMS.In the linear regression analysis,border tissue angle was negatively associated with PHOMS height(β=-2.227,P<0.001).CONCLUSION:PHOMS is associated with optic disc tilt and optic disc nasal shift in myopia.Disc diameter is not a risk factor for PHOMS.The changes in ONH caused by axial elongation facilitated an understanding of the mechanism of PHOMS.

Peripapillary intrachoroidal cavitation at the crossroads of peripapillary myopic changes

AIM:To analyze the prevalence of peripapillary intrachoroidal cavitation(PICC)in eyes with gamma peripapillary atrophy(γPPA),in eyes with peripapillary staphyloma(PPS)and in those combiningγPPA and PPS and to analyze border tissue discontinuity in PICC.METHODS:This prospective cross-sectional non interventional study included highly myopic eyes.Non-highly myopic eyes were used as control.Radial and linear scans centered on the optic nerve head were performed using spectral-domain optical coherence tomography.Variables were analyzed along the twelve hourly optical coherence tomography sections in both eyes of each subject.RESULTS:A total of 667 eyes of 334 subjects were included:229(34.3%)highly myopic eyes and 438(65.7%)non highly myopic eyes.The mean age of the highly myopic group was 48.99±17.81y.PICC was found in a total of 40 eyes and in 13.2%(29/220)of highly myopic eyes.PICC was found in 10.4%(40/386)of eyes withγPPA,in 20.5%(40/195)of eyes with PPS and in 22.7%(40/176)of those combiningγPPA and PPS.All the eyes with PICC showed the co-existence ofγPPA and PPS whereas none of the eyes presenting only one of these entities exhibited PICC.A border tissue discontinuity in theγPPA area was found in all eyes with PICC.CONCLUSION:We confirm the presence of a border tissue discontinuity in theγPPA area of all eyes with PICC.These findings suggest the involvement of mechanical factors in the pathogenesis of PICC which may contribute to PICC-related visual field defects.

Structural impairment patterns in peripapillary retinal fiber layer and retinal ganglion cell layer in mitochondrial optic neuropathies

AIM：To evaluate the structural injure patterns in peripapillary retinal fiber layer （pRNFL）, retinal ganglion cell layer （RGCL） and their correlations to visual function in various mitochondrial optic neuropathies （MON） to offer help to their differential diagnosis.METHODS：Totally 32 MON patients （60 eyes） were recruited within 6mo after clinical onsets, including 20 Leber hereditary optic neuropathy （LHON） patients （37eyes）, 12 ethambutol-induced optic neuropathy （EON）patients （23 eyes）, and 41 age-gender matched healthy controls （HC, 82 eyes）. All subjects had pRNFL and RGCL examinations with optic coherence tomography （OCT） and visual function tests.RESULTS：In the early stages of MON, the temporal pRNFL thickness decreased （66.09±22.57μm）, but increased in other quadrants, compared to HC （76.95±14.81μm）. The other quadrants remaining stable for LHON and EON patients besides the second hour sector of pRNFL thickness reduced and the temporal pRNFL decreased （56.78±15.87μm） for EON. Total macular thickness in MON reduced remarkably（279.25±18.90μm; P=0.015）, which mainly occurring in the inner circle （3 mm diameter of circle） and the nasal temporal sectors in the outer circle （5.5 mm diameter of circle）, in contrast to those in HC. RGCL thickness reduced in each sector of the macula （61.90±8.73μm; P≤0.001）. It strongly showed the correlationship of best corrected visual acuity （R=0.50, P=0.0003） and visual field injury （R=0.54,P=0.0002） in MON patients.CONCLUSION：OCT is a potential tool for detecting structural alterations in the optic nerves of various MON. Different types of MON may have different damage patterns.

Optic disc and peripapillary changes by optic coherence tomography in high myopia

Myopia,a worldwide condition,is a multifactorial disease resulting in many ocular complications.Early onset of myopia has a great tendency to develop high myopia and pathological myopia later in life.The pathophysiology and progression of myopia is still unclear.Owing to its involving in visual function,optic disc and peripapillary change in high myopia can＇t be neglected,and it may help in better understanding of the pathophysiology or mechanism of myopia progression.Recently,advanced imaging techniques have been developed,such as optical coherence tomography（OCT）,allowing for better detecting of optic disc and peripapillary change.OCT is a highresolution and noninvasive measurement for detection of ocular structure.Herein,we provide an updated review of optic disc and peripapillary change in OCT image,including its characteristics and clinical significance.We also propose some problems needed further investigation.

Sectoral changes of the peripapillary choroidal thickness in patients with unilateral branch retinal vein occlusion

AIM: To investigate sectoral changes in the mean peripapillary choroidal thickness(PCT) in patients with unilateral branch retinal vein occlusion(BRVO). METHODS: This retrospective, interventional study included 41 patients with acute, unilateral BRVO without macular edema. All patients completed at least a 6-month follow-up period. The PCT was measured at eight locations(temporal, superotemporal, superior, superonasal, nasal, inferonasal, inferior, and inferotemporal). In addition to calculating the average of all locations, the peripapillary choroidal area was divided into four sectors: superior(average of superotemporal PCT, superior PCT, and superonasal PCT), temporal, inferior(average of inferotemporal PCT, inferior PCT, and inferonasal PCT), and nasal. RESULTS: In the BRVO-affected eyes, the mean PCT was 177.7±69.8 μm(range, 70.1-396.0 μm) at baseline and 127.8±54.8 μm(range, 56.4-312.1 μm) at 6 mo(P<0.001). In the non-affected contralateral eyes, the mean PCT was 192.5±60.6 μm(range, 61.4-365.0 μm) at baseline and 165.9±61.1 μm(range, 56.8-326.8 μm) at 6 mo(P<0.001). In sectoral analysis, the mean PCT in each sector was significantly reduced in over 6 mo in the BRVO-affected eyes(all P<0.001). In the non-affected contralateral eyes, the mean PCT was not significantly changed in any sector over the 6-month follow-up period(superior sector, P=0.143; temporal sector, P=0.825; inferior sector, P=0.192; and nasal sector, P=0.599).CONCLUSION: Sectoral analysis shows that the mean PCTs in all sectors are reduced significantly over 6 mo in the BRVO-affected eyes, but not in the non-affected contralateral eyes.

Optical coherence tomography with or without enhanced depth imaging for peripapillary retinal nerve fiber layer and choroidal thickness

AIM：To assess peripapillary retinal nerve fiber layer（RNFL）and choroidal thickness obtained with enhanced depth imaging（EDI）mode compared with those obtained without EDI mode using Heidelberg Spectralis optical coherence tomography（OCT）.METHODS：Fifty eyes of 25 normal healthy subjects and32 eyes of 20 patients with different eye diseases were included in the study.All subjects underwent 3.4 mm diameter peripapillary circular OCT scan centered on the optic disc using both the conventional and the EDI OCT protocols.The visualization of RNFL and choroidoscleral junction was assessed using an ordinal scoring scale.The paired t-test,intraclass correlation coefficient（ICC）,95%limits of agreement（LoA）,and Bland and Altman plots were used to test the agreement of measurements.RESULTS：The visibility score of RNFL obtained with and without EDI was of no significant difference（P=0.532）,the visualization of choroidoscleral junction was better using EDI protocol than conventional protocol（P〈0.001）.Peripapillary RNFL thickness obtained with EDI was slightly thicker than that obtained without EDI（103.25±9.42μm vs 101.87±8.78μm,P=0.010）.The ICC of the two protocols was excellent with the value of 0.867 to 0.924,the 95%LoA of global RNFL thickness was between-10.0 to 7.4μm.Peripapillary choroidal thickness obtained with EDI was slightly thinner than that obtained without EDI（147.23±51.04μm vs 150.90±51.84μm,P〈0.001）.The ICC was also excellent with the value of 0.960 to 0.987,the 95%LoA of global choroidal thickness was between-12.5 to 19.8μm.CONCLUSION：Peripapillary circular OCT scan with or without EDI mode shows comparable results in the measurement of peripapillary RNFL and choroidal thickness.

Analysis of Radial Peripapillary Capillary Density in Patients with Bietti Crystalline Dystrophy by Optical Coherence Tomography Angiography

Objective We wanted to investigate the radial peripapillary capillary(RPC)network in patients with Bietti crystalline dystrophy(BCD).Methods We compared RPC densities in the disk and different peripapillary regions,obtained using optical coherence tomography angiography in 22 patients with BCD(37 eyes)and 22 healthy subjects(37 eyes).The BCD group was then divided into Stage 2 and Stage 3 subgroups based on Yuzawa staging,comparing the RPC densities of the two.Results The disk area RPC density was 38.8%±6.3%in the BCD group and 49.2%±6.1%in the control group(P<0.001),and peripapillary region RPC density was significantly lower in the BCD group than in the control group(49.1%±4.7%and 54.1%±3.0%,respectively,P<0.001).There were no significant RPC density differences between the tempo quadrant and inside disk of Stages 2 and 3 subgroups;the other areas showed a significantly lower RPC density in Stage 3 than in Stage 2 BCD.Conclusion The BCD group RPC density was significantly lower than the control group.The reduction of RPC density in the tempo quadrant occurred mainly in the Stage 1 BCD.In contrast,the reduction of RPC density in superior,inferior,and nasal quadrants occurred mainly in Stage 2.

Reduced choroidal peripapillary capillaries in thyroid-associated ophthalmopathy with early stage of dysthyroid optic neuropathy

AIM: To investigate whether the subtle change of choroidal/retinal vessel densities and volumes in thyroidassociated ophthalmopathy(TAO) could be an early sign to detect dysthyroid optic neuropathy(DON). METHODS: This was a retrospective cross-sectional study, and a total of 98 eyes from 50 subjects were enrolled under certain criteria. Thirty-four eyes of normal controls and 64 eyes of TAO, including 39 eyes of DON and 25 eyes of TAO without DON, underwent optical coherence tomography angiography(OCTA) scanning. All the tested parameters of OCTA scanning including choroid radial peripapillary capillaries(RPC), retinal nerve fiber layer(RNFL), and macular ganglion cell complex(GCC) were compared among groups, and the correlation between OCTA parameters and visual function parameters was also investigated. RESULTS: Whole choroidal RPC was significantly reduced in DON(48.24%±0.4978%) compared to normal(50.33%±0.3173%) and TAO without DON(49.16%±0.5463%;P=0.0041). The reduction of whole choroidal RPC was also correlated with visual field(VF) defect in DON(r=0.5422, n=39). Although vision acuity and VF were improved in all the patients with DON after being treated with medical and surgical decompression, the reduction of RPC density were not reversed.CONCLUSION: There is a notable reduction in choroidal RPC in DON, which is correlated with VF defect. The reduction of RPC density could not be reversed immediately by medical and surgical decompression even when vision and VF were improved. These findings suggest that choroidal RPC could be a useful parameter to diagnose and monitor early stage of DON.

Peripapillary choroidal thickness in Chinese children using enhanced depth imaging optical coherence tomography

AIM：To evaluate the peripapillary choroidal thickness（PPCT） in Chinese children,and to analyze the influencing factors.METHODS： PPCT was measured with enhanced depth imaging optical coherence tomography（EDI-OCT） in 70children（53 myopes and 17 non-myopes） aged 7 to 18 y,with spherical equivalent refractive errors between 0.50and-5.87 diopters（D）.Peripapillary choroidal imaging was performed using circular scans of a diameter of 3.4 mm around the optic disc.PPCT was measured by EDI-OCT in six sectors： nasal（N）,superonasal（SN）,superotemporal（ST）,temporal（T）,inferotemporal（IT）and inferonasal（IN）,as well as global RNFL thickness（G）.RESULTS： The mean global PPCT was 165.49±33.76 μm.The temporal,inferonasal,inferotemporal PPCT were significantly thinner than the nasal,superonasal,superotemporal segments PPCT were significantly thinner in the myopic group at temporal,superotemporal and inferotemporal segments.The axial length was significantly associated with the average global（β=-0.419,P =0.014）,superonasal（β=-2.009,P=0.049） and inferonasal（β=-2.000,P=0.049） PPCT.The other factors（gender,age,SE） were not significantly associated with PPCT.CONCLUSION： PPCT was thinner in the myopic group at temporal,superotemporal and inferotemporal segments.The axial length was found to be negatively correlated to PPCT.We need more further studies about the relationship between PPCT and myopia.

Changes in peripapillary retinal nerve fiber layer thickness in patients with primary open-angle glaucoma after deep sclerectomy

AIM： To assess changes in peripapillary retinal nerve fiber layer （RNFL） thickness and visual field （VF） in patients with glaucoma after reduction of intraocular pressure （IOP）. METHODS： Thirty-five consecutive patients with bilat-eral high tension glaucoma were included in the study. Thirty-five eyes underwent monocular deep sclerectomy （surgery group） and the medically treated fellow eyes served as controls （control group）. Quantitative analyses of the peripapillary RNFL thickness by optical coherence tomography （OCT） and global VF indices by automated perimetry were performed before surgery and six months after surgery in both eyes. The changes in RNFL thickness overall and by quadrant were evalu-ated and studied with respect to age, best-corrected visual acuity （BCVA）, preoperative global VF indices, postoperative IOP changes, and postoperative changes in global VF indices. Changes observed in RNFL thickness and VF indices were compared between eyes after surgery and fellow eyes. RESULTS： Six months after surgery, the overall IOP decreased from a baseline mean of 24.5 ± 3.2 mmHg to 11.5 ± 2.7 mmHg （P 〈 0.001） at the time of OCT testing. A signifcant increase in the overall mean RNFL thickness was observed after surgery （P 〈 0.001）. The preoperative VF mean deviation was significantly cor-related with a postoperative increase in the RNFL thick-ness （P 〈 0.075）. No correlation was found between RNFL thickness changes and age, BCVA, or changes in the global VF indices. There was no significant difference between eyes with an IOP reduction of more than 50% and those with a reduction in IOP less than 30% （ P = 0.312）.CONCLUSION： A signifcant increase in the peripapil-lary RNFL thickness was associated with IOP reduction by glaucoma filtration surgery as measured by OCT.

Retinal capillary density among healthy Egyptian and South Asian students:an optical coherence tomography angiography study

AIM:To compare the macular and optic nerve perfusion and vascular architecture using optical coherence tomography angiography(OCTA)in normal eyes of Egyptian(Caucasians)and South Asian(Asians)volunteers.METHODS:Cross-sectional analytical OCTA study performed on 90 eyes of South Asian(n=45)and Egyptians(n=45)were analyzed.All participants underwent bestcorrected visual acuity test,slit lamp,and fundus examination.OCTA images;macular 6×6 mm^(2) grid and optic nerve 4.5×4.5 mm^(2) grid were used to examine the parafoveal and peripapillary regions,respectively.RESULTS:The mean capillary vessel density(CVD)in macular sectors among South Asians and Egyptians participants were(50.31%±2.53%,51.2%±5.93%)and(49.71%±3.6%,51.94%±4.79%)in superficial(SCP)and deep capillary plexuses(DCP),respectively(P>0.05).Mean CVD in both groups was higher in DCP compared to SCP in all sectors but was not significant(P>0.05).Mean foveal CVD increases with an increase in central retinal thickness in both SCP and DCP(P<0.001),among both groups.Mean area of the foveal avascular zone(FAZ)was 0.28±0.09 and 0.27±0.08 mm2 in South Asian and Egyptians,respectively.FAZ area decreases with an increase in the thickness and foveal CVD(P<0.001).Mean CVD in the peripapillary area was 48.23%±5.78% in South Asian and 49.52%±2.38% in Egyptian volunteers.The mean retinal nerve fiber layer thickness was found to be higher in the nasal quadrant among South Asian females than the Egyptian females(P<0.05).CONCLUSION:No significant racial disparity is found in this study.The findings are helpful for assessing and improving the normative data on the differences in South Asian and Egyptian populations.

Altered birefringence of peripapillary retinal nerve fiber layer in multiple sclerosis measured by polarization sensitive optical coherence tomography

Background:The retina has been used to study the pathophysiology of multiple sclerosis(MS).Peripapillary retinal nerve fiber layer(pRNFL)thinning has been suggested as an ocular biomarker of neurodegeneration in MS.The goal of this project was to determine the birefringence of the pRNFL by measuring the fiber birefringence using polarization sensitive optical coherence tomography(PS-OCT).Methods:Sixty-six MS patients without history of optic neuritis(age:39.9±11.0 yrs.old,53 females and 13 males)and 66 age-and gender-matched normal controls(age:40.7±11.4 yrs.old)were recruited.Custom built PS-OCT was used to measure phase retardation per unit depth(PR/UD,proportional to the birefringence)and pRNFL thickness in each quadrant of the pRNFL.In addition,clinical manifestation was used to correlate with the pRNFL birefringence.Results:The pRNFL was thinner in the temporal and inferior quadrants in MS patients compared with normal controls(P<0.05).The PR/UD of the pRNFL was significantly decreased in MS patients(P<0.05)in all quadrants except for the nasal quadrant.In both groups,the PR/UD from all four quadrants was not related to the averaged pRNFL thickness(P>0.05).In MS patients,the PR/UD was not related to the expanded disability status scale(EDSS)nor disease duration(r ranged from−0.17 to 0.02,P>0.05).Conclusion:This is the first study using PS-OCT to study the pRNFL birefringence in MS patients.Decreased birefringence of the pRNFL may indicate microtubule abnormality,and could be a potential biomarker for detecting early neurodegeneration in MS.

Stem Cell Ophthalmology Treatment Study (SCOTS)： improvement in serpiginous choroidopathy following autologous bone marrow derived stem cell treatment

We report results in a 77-year-old male patient with visual loss from long-standing serpiginous choroidop- athy treated with bone marrow derived stem cells （BMSC） within the Stem Cell Ophthalmology Treatment Study （SCOTS）. SCOTS is an Institutional Review Board approved clinical trial and the largest ophthal- mology stem cell study registered at the National Institutes of Health to date （ClinicalTrials.gov Identifier： NCT01920867）. Eight months after treatment by a combination of retrobulbar, subtenon, intravitreal and intravenous injection of BMSC, the patient＇s best corrected Snellen acuity improved from 20/80- to 20/60.1 in the right eye and from 20/50- to 20/20 3 in the left eye. The Early Treatment of Diabetic Retinopathy Study （ETDRS） visual acuity continued to improve over the succeeding 8 months and the optical coherence tomography macular volume increased. The increases in visual acuity and macular volume are encouraging and suggest that the use of BMSC as provided in SCOTS may be a viable approach to treating serpiginous choroidopathy.

Quantitative analysis of optic disc changes in school-age children with ametropia based on artificial intelligence

AIM:To explore changes in the optic disc and peripapillary atrophy(PPA)in school-age children with ametropia using color fundus photography combined with artificial intelligence(AI)technology.METHODS:Based on the retrospective case-controlled study,226 eyes of 113 children aged aged 6–12y were enrolled from October 2021 to May 2022.According to the results of spherical equivalent(SE),the children were divided into four groups:low myopia group(66 eyes),moderate myopia group(60 eyes),high myopia group(50 eyes)and emmetropia control group(50 eyes).All subjects underwent un-aided visual acuity,dilated pupil optometry,best-corrected visual acuity(BCVA),intraocular pressure,ocular axis measurement and color fundus photography.RESULTS:The width of PPA,horizontal diameter ratio of PPA to the optic disc and area ratio of PPA to the optic disc were significantly different among the four groups(P<0.05).The width of the nasal and temporal neuroretinal rim,the roundness of the optic disc,the height of PPA,the vertical diameter ratio of PPA to the optic disc,and the average density of PPA in the high myopia group were significantly different compared with the other three groups(P<0.05).There were strong negative correlations between SE and area ratio of PPA to the optic disc(r=-0.812,P<0.001)and strong positive correlation between axial length(AL)and area ratio of PPA to the optic disc(r=0.736,P<0.001).CONCLUSION:In school-age children with high myopia,the nasal and temporal neuroretinal rims are narrowed and even lost,which have high sensitivity.The area ratio of the PPA to the optic disc could be used as an early predictor of myopia progression,which is of great significance for the development prevention and management of myopia.

Macular thickness as a predictor of loss of visual sensitivity in ethambutol-induced optic neuropathy

Ethambutol is a common cause of drug-related optic neuropathy.Prediction of the onset of ethambutol-induced optic neuropathy and consequent drug withdrawal may be an effective method to stop visual loss.Previous studies have shown that structural injury to the optic nerve occurred earlier than the damage to visual function.Therefore,we decided to detect structural biomarkers marking visual field loss in early stage ethambutol-induced optic neuropathy.The thickness of peripapillary retinal nerve fiber layer,macular thickness and visual sensitivity loss would be observed in 11 ethambutol-induced optic neuropathy patients（22 eyes） using optical coherence tomography.Twenty-four healthy age-and sex-matched participants（48 eyes） were used as controls.Results demonstrated that the temporal peripapillary retinal nerve fiber layer thickness and average macular thickness were thinner in patients with ethambutol-induced optic neuropathy compared with healthy controls.The average macular thickness was strongly positively correlated with central visual sensitivity loss（r2=0.878,P=0.000）.These findings suggest that optical coherence tomography can be used to efficiently screen patients.Macular thickness loss could be a potential factor for predicting the onset of ethambutol-induced optic neuropathy.

Correlations between the optic nerve head morphology and ocular biometrics in highly myopic eyes

AIM： To analyze peripapillary atrophy β/γ zone （PPA-β/γ） and the optic disc ovality index, and to assess their associations with the axial length （AL）, refractive error, best corrected visual acuity （BCVA）, choroidal thickness （CT）, and age in highly myopic eyes. METHODS： This was a retrospective observational case series. The study included 667 patients consecutively examined for highly myopic eyes [spherical equivalent ≤-6.0 diopters （D） and AL≥26 mm] with or without myopic retinopathy. Each patient went through a comprehensive ophthalmological examination that included spectral domain optical coherence tomography （SD-OCT） of the macula, A-mode ultrasonography, and a cycloplegic refraction test. The ovality index and PPA-β/γ area were measured from optic disc photographs. RESULTS： A significant association was seen between PPA-β/γ area and the ovality index （P=0.000, r=-0.232）. The PPA-β/γ area increased significantly with a longer AL, older age, worse BCVA, higher refractive error, and thinner choroid （P〈0.01）. The oval disc was significantly correlated with a longer AL, older age, worse BCVA, higher refractive error, larger PPA-β/γ area, and thinner choroid （P〈0.01）. CONCLUSION： The PPA-β/γ zone and ovality index in highly myopic eyes show distinct associations with the AL, refractive error, BCVA, age, and CT.

Analysis of retinal vasculature changes in indirect traumatic optic neuropathy using optic coherence tomography angiography

AIM:To assess the retinal vasculature alterations in indirect traumatic optic neuropathy(ITON)patients following craniofacial trauma by optic coherence tomography angiography(OCTA).METHODS:Patients diagnosed of monocular ITON were recruited from August 2016 to May 2020.OCTA was performed using the Angio Vue OCT-A system for two cube scans centered at the optic nerve head and fovea.OCTA data included thicknesses of peripapillary retinal nerve fiber layer(RNFL)and macular ganglion cell complex(GCC),as well as proportion of capillary perfusion and data were analyzed for correlation with post-injury timepoints:within 7,8-30,31-90,and 91-365d.RESULTS:A total of 73 ITON patients were studied.Significant thinning of RNFL and GCC layers and attenuation of microvascular perfusion were observed in ITON eyes as compared to contralateral unaffected eyes(for most of the analyzed sectors and quadrants,P<0.05).Without respect to surgical intervention and vision recovery,the decrease in retinal layer thicknesses and microvascular perfusion was time-dependent,and most significant within three months(P<0.001).CONCLUSION:ITON presents with time-dependent thinning of retinal layers and attenuation of microvasculature,indicating possible degeneration of retinal ganglion cells due to reduced retinal blood supply.

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.

The association of cerebrospinal fluid pressure with optic nerve head and macular vessel density

The present study aims to investigate the effect of temporary cerebrospinal fluid pressure(CSFP) reduction on optic nerve head(ONH) and macular vessel density(VD) using optical coherence tomography angiography.Forty-four eyes of 44 adults with diagnostic lumbar puncture and CSFP reduction were recruited.Thirty-two eyes of 32 healthy volunteers were controls.ONH and macular VD images were evaluated differences between baseline and after CSFP reduction.The results showed that the mean CSFP decreased from(11.6±2.1) mm Hg to(8.2±3.4) mm Hg(P<0.001).VD in the macular regions decreased significantly after CSFP reduction in the study group(all P<0.05).The control group showed no significant changes in macular VD(all P>0.05).In the study group,decreased VD in the macular parainferior region was associated with CSFP reduction(R^(2)=0.192,P=0.003),the reduction of macular VD in parafoveal(R^(2)=0.098,P=0.018),parainferior(R^(2)=0.104,P=0.021),parasuperior(R^(2)=0.059,P=0.058),paranasal(R^(2)=0.057,P=0.042),paratemporal(R^(2)=0.079,P=0.026) was associated with mean ocular perfusion pressure decrease following CSFP reduction.ONH vessel density did not differ after CSFP reduction(all P>0.05).In conclusion,macular vessel density decreased in association with CSFP reduction.Retinal vessel density in the macular region is more sensitive than that in peripapillary region after CSFP reduction.