Retinal structural-vascular-functional relationship using optical coherence tomography and optical coherence tomography -angiography in myopia

Background:To examine the retinal structure–vascular-function relationship using optical coherence tomography(OCT)and optical coherence tomography angiography(OCTA)in myopia.Methods:This was a prospective cross-sectional study comprising 86 eyes of 45 individuals with varying axial lengths and spherical equivalents and no posterior segment abnormalities.All eyes underwent optical coherence tomography with the Spectralis SD-OCT and OCTA with RTVue-XR Avanti;Optovue.Individual macular retinal layer thicknesses and flow areas and vessel densities were measured on OCT and OCTA,respectively.Linear correlations were made between the macular layer thicknesses,flow areas and vessel densities with axial length,spherical equivalent and visual acuity.Results:The participants’mean ages were 33.34±14.45 years,mean spherical equivalent refractions were−7.17±5.71 D and axial lengths were 25.95±2.41 mm.There were significant positive correlations of foveal angle(r=0.757,p=0.001),inner retinal(r=0.764,p=0.001)and outer plexiform layer(r=0.771,p=0.001)thickness on OCT and vessel densities in deep capillary plexus(r=0.313,p=0.003)on OCTA with axial length and negative correlations with spherical equivalents and visual acuity.Significant negative correlations of outer nuclear layer(r=−0.560,p=0.03)and photoreceptor outer segment layer thickness(r=−0.856,p<0.001)were noted on OCT with axial length and positive correlations with spherical equivalents and visual acuity.Conclusion:The lateral retinal stretching in myopia could possibly explain the correlation between retinal layer thickness,vascular density and visual acuity in these eyes.Further research is required to investigate this.

Ab externo canaloplasty results and efficacy: a retrospective cohort study with a 12-month follow-up

Background:The aim of this study is to review the outcomes of canaloplasty versus canaloplasty combined with phacoemulsification in a retrospective cohort study and to evaluate the efficacy of these methods in terms of intraocular pressure(IOP)lowering effect,postoperative complications and additional glaucoma surgery or reintroduction of medical therapy over a 12-month follow-up.Methods:In a retrospective cohort study,602 eyes with primary open angle glaucoma(POAG)were treated with canaloplasty or canaloplasty combined with phacoemulsification.The results were evaluated separately in two main groups;group A canaloplasty(262 eyes)and group B canaloplasty combined with phaco(322 eyes).Each group was then subdivided into three additional groups according to the severity of glaucoma.The criteria for successful treatment were evaluated between three IOP ranges;IOP≤16 mmHg,18 mmHg and 21 mmHg.Complete success was considered the percentage of eyes reaching target IOP with no medication and partial success with medication.Groups A and B subgroups were compared using the Kaplan Meier test.Mean IOP,reduction of antiglaucoma agents and additional IOP lowering methods were also evaluated.The follow-up time was 12 months.Statistical significance was set at p<0.05.Results:An incomplete intraoperative cannulation of Schlemm’s canal resulting in conversion to other glaucoma surgery occurred in 18 eyes(2.99%).In both of the main groups,postoperative hyphema,descemet membrane detachment and transient IOP rise were the most common postoperative complications.The mean IOP in group A and subgroups at 12 months was 13.26±4.5 mmHg,15.19±3.97 mmHg and 18.09±3.75 mmHg.Respectively in group B mean IOP was 14.51±4.69 mmHg,14.40±4.11 mmHg and 14.25±2.76 mmHg.Complete success was achieved in group A in 69.19,74.51 and 74.31%of eyes.In group B complete success was achieved in 81.60,77.33 and 83.33%of eyes respectively.Kaplan Meier between groups A and B was statistically significant for IOP≤16 mmHg and IOP≤21 mmHg(p=0.0041 and p=0.0312),but not for IOP≤18 mmHg(p=0.6935).Partial success for IOP≤16 mmHg was 95.23 and 92.26%,for IOP≤18 mmHg was 91.66 and 90.47%and for IOP≤21 mmHg,90.00 and 93.10%,in groups A and B respectively.Twenty-three eyes received additional surgery(3.93%),10 trabeculectomies and 2 cyclophotocoagulation in group A,and 9 trabeculectomies and 2 cyclophotocoagulation in group B.Conclusion:Canaloplasty and canaloplasty combined with phacoemulsification significantly lower the IOP and have a lower postoperative complication rate.Additional glaucoma surgery or medication following both procedures is necessary if target IOP is unsatisfactory.In this study,canaloplasty combined with phacoemulsification demonstrated superior success rate compared to canaloplasty alone.

Quantifying microstructural changes in retinitis pigmentosa using spectral domain – optical coherence tomography

Background:Most patients of established retinitis pigmentosa(RP)have subnormal peripheral vision and heavily rely on central vision for their daily activities.Central visual acuity is dependent on photoreceptor survival at the macula.Identification of structural changes that precede visual loss is essential.The aim of this study was to correlate the Spectral Domain-Optical Coherence Tomography(SD-OCT)characteristics with visual acuity in patients with typical RP.Methods:This was a retrospective,observational case series of 224 eyes of 113 RP patients conducted a tertiary eye care center.SD-OCT imaging was done for all eyes.Central retinal thickness(CRT),photoreceptor outer segment length(PROS),foveal outer segment pigment epithelial thickness(FOSPET)and ellipsoid zone(EZ)extent were measured.A new variable,FOSPET-PROS ratio(FPR),obtained by dividing FOSPET by PROS is defined and correlated to corrected distance visual acuity(CDVA)in logMAR using linear regression.Results:Out of 113 patients,71 were males and 42 females.Mean age of the patients was 35.4±15.1 years.Mean CDVA was 0.33±0.25 logMAR with no difference between the genders.Mean CRT(218.74±83.5μm)and FPR(1.63±0.22)significantly correlated to CDVA with a correlation coefficient of r=−0.139(p=0.048)and r=0.842(p=0.0001),respectively.FOSPET(mean=71.15±13.8μm)and PROS(mean=44.85±12.5μm)did not show a significant correlation to CDVA,independent of FPR.Conclusions:Retinal microstructural changes on SD-OCT,especially the FPR,can be used as a surrogate marker to monitor disease progression in the central retina in degenerative diseases like RP.

皮革通过厌氧途径的生物降解性

制革过程中会产生大量的液体和固体废物，固体废物尤其是鞣制废渣的治理是制革技术人员面对的重要问题。因此，皮革生物降解性的研究成为急切而重要的课题。本论文讨论了鞣前皮坯、铬鞣革和植鞣革在厌氧环境下的生物降解性，并在研究中使用了两种不同的厌氧菌源。同时研究丁皮革降解前，脱鞣作为前处理的影响。研究发现，植鞣举比铬鞣革在牛物降解过程中产生更多的气体物质。当混合厌氧菌株作为接种物时，能降解植鞣革中的可溶性有机物，因此用厌氧性活性污泥处理植鞣革，在初始几天气体产牛量增加。对于铬鞣革，使用不同的两种菌源在气体产生量上并无太大变化。同时发现脱鞣有利于促进两种革的生物降解。

The impact of dysfunctional tear films and optical aberrations on chronic migraine

Background:Migraine is a multifactorial disorder with complex neuronal and vascular mechanisms that encompasses a wide clinical spectrum of symptoms,including ocular manifestations.Dry eye disease and dysfunction of ocular somatosensory pathways have been implicated in the pathogenesis.The current study investigates the association between a dysfunctional tear film and ocular aberrations with migraine.Methods:Sixty eyes of 30 patients with migraine and 60 eyes of 30 controls were studied.Dry eye evaluation included Schirmer’s test,tear film break-up time,corneal esthesiometry and lipid layer analysis using Lipiview^(®)interferometer.Wavefront aberrations were measured using Optical Path Difference before performing the dry eye evaluation.The intraocular light scatter was quantified using the objective scatter index(OSI)of the optical quality analysis system.Measured parameters were compared between the migraine and the control group using independent sample t-test.Statistical analysis was performed using commercial software.A p value of≤0.05 was considered statistically significant.Results:There were 19 females and 11 males in each group.Statistically significant difference was found between the two groups with respect to total aberrations(p=0.049),higher order aberrations(p=0.009),coma(p=0.03),spherical aberrations(p=0.018),Lipiview interferometric coloric units(p<0.001)and OSI(p<0.001).Trefoil(p=0.26)and TBUT(p=0.398)were not significantly different between both groups.Conclusions:Ocular aberrations are higher in patients with migraine as compared with controls.Tear film abnormalities add to the aberrations in otherwise asymptomatic patients and may also be associated with migraineous attacks.Treating the ocular surface to obtain a healthy tear film might introduce a potential modifiable factor in the prevention of migraneous attacks.

Correction to:The impact of dysfunctional tear films and optical aberrations on chronic migraine

Correction After publication of this article[1]it came to our attention that Table 1 was presented incorrectly.The correct table can be found below。