Risk factors for posterior synechiae of the iris after 23-gauge phacovitrectomy

AIM:To identify risk factors for the development of posterior synechiae of the iris(PSI) after 23-gauge phacovitrectomy.METHODS:A retrospective chart review was performed in consecutive Asian patients treated with 23-gauge phacovitrectomy with a 3-piece intraocular lens(IOL) or a single-piece 4 haptics IOL.RESULTS:A total of 263 eyes from 242 patients were included in the study. Postoperative PSI was identified in16(6.1%) eyes. In multivariate analysis, C3F8 gas tamponade, oil tamponade, and long operation time were significantly associated with PSI formation. There was no difference in the incidence of PSI between the groups using two different types of IOL(P =0.779).·CONLUSION: C3F8 gas or oil tamponade and long operation time increased the incidence of PSI after 23-gauge phacovitrectomy. The single-piece 4 haptics IOL,in lieu of a 3-piece IOL, may be inserted into the capsular bag with a comparable incidence of PSI.

Microperimetry and spectral domain optical coherence tomography in myelinated retinal nerve fibers

Dear Sir,I write to present the correlation between microperimetric （MP） values and the density of myelinated retinal nerve fibers （MNFs） in optical coherence tomography （OCT） imaging.

Macular hole closure following anti-vascular endothelial growth factor injection in an eye with myopic choroidal neovascularization

Dear Editor,I am Cheolmin Yun,from the Department of Ophthalmology,Korea University College of Medicine.I write to present a case report of a female patient with a myopic patient suffering from atrophic choroidal neovascularization（CNV）and a full thickness macular hole（FTMH）,who was treated with an intravitreal anti-vascular endothelial growth factor （VEGF） injection without vitrectomy.

Comparison of ring 1 parameters in 37-segment multifocal electroretinography between onset and offset conditions of ring 2 to 4 in normal subjects

AIM: To investigate whether the response of a central hexagonal element corresponding to the macular area in conventional multifocal electroretinography(mfERG) tests was the same as that of experimental mfERG using single central hexagonal element stimulation. METHODS: Prospective, observational study. Thirty healthy subjects were included in this study. mfERG recordings were performed according to two protocols: stimulus with 37 hexagonal elements(protocol 1), and stimulus with a single central element created by deactivating the other 36 hexagonal elements(protocol 2). We compared differences between ring 1 parameters in each protocol. RESULTS: In protocol 1, the first positive component(P1) implicit time and P1 amplitude were 37.8±1.8 ms and 6.3±2.7 μV. After single element stimulation(protocol 2), double positive waves appeared. The implicit time and amplitude of P1 were 40.7±2.4 ms(P<0.001) and 9.1±3.3 μV(P=0.001), respectively. The implicit time and amplitude of the second positive component(P2) were 68.0±4.5 ms(P<0.001, compared with P1 in protocol 1) and 12.3±4.7 μV(P<0.001, compared with P1 in protocol 1), respectively. The amplitude of P2 in protocol 2 was about two times higher than that of P1 in protocol 1. CONCLUSION: mfERG responses of a central hexagonal element in a single element stimulation protocol are different from those of multiple element stimulation. The positive wave is more enhanced compared to that of the conventional protocol and it elongated into two wavelets.

Changes on optical coherence tomography angiography and fluorescein angiography in eyes with neovascular age-related macular degeneration

AIM:lo evaluate the changes on optical coherence tomography angiography(OCTA) and fluorescein angiography(FA) and their correlation in neovascular agerelated macular degeneration(nAMD) before and after intravitreal aflibercept injections(IAIs).METHODS:In 43 treatment-na?ve patients with nAMD,choroidal neovascularization(CNV) in OCTA were morphologically and quantitatively analyzed before and after IAIs to determine whether they are correlated with leakage on FA or not.By combining CNV in OCTA and leakage in FA,lesions were characterized as three types:L+C+(with both CNV and leakage),L-C+(with CNV but without leakage),or L+C-lesion(with leakage outside CNV).RESULTS:Before IAI,while 27 eyes had L+C+lesion only,16 eyes had both L+C+and L-C+lesions simultaneously.Tiny capillaries and anastomosis in CNV were more developed in L+C+lesion,at 86.0% and58.1%,respectively,relative to 9.3% and 9.3% in L-C+lesions(P<0.001).After IAIs in 33 eyes,tiny capillaries and anastomosis were decreased in the lesions with cessation of leakage on FA(P<0.001 and P=0.001,respectively).In quantitative analysis,neovascularization length and numbers of junctions and endpoints were also significantly decreased.CONCLUSION:Leakage on FA is associated with CNV morphology in OCTA and remained so after IAls.Therefore,by carefully assessing the morphological and quantitative changes of CNV in OCTA before and after treatment,activity of nAMD is expected even though CNV on OCTA is not completely matched with fluorescein leakage.

Cu enrichment behavior at steel-scale interface during high temperature oxidation of Cu containing steel

In order to suppress the surface cracking induced by Cu during reheating and hot rolling process,Cu enrichment and its migration at the steel-scale interface was investigated during heating of steel cast at temperatures between 1000℃and 1200℃in N_2-O_2 and N_7-H_2O atmospheres.For oxidation of Cu containing steel,Cu enriched phase was formed by the preferential oxidation of Fe and the enrichment and migration behavior of Cu depends on the oxidation temperature,steel chemistry and atmosphere condition.Ni in steel induced the formation of solid Cu and Ni enriched phase at steel/scale interface and in scale layer and the formation of uneven steel/scale interface, which suppresses the Cu enrichment because of extrusion of Cu enriched region before the formation of liquid phase.On the other hand,Sn addition promotes the liquid Cu formation at steel/scale interface and penetration into grain boundary of Cu enriched phase by decreasing solidus temperature and solubility limit.In addition,for oxidation at 1 200℃,the behavior of Cu at and around the steel-scale interface was found dependent to a large extent on morphology of the oxide scale formed during oxidation.At the early stage of oxidation,Cu-rich phase formed and accumulated at the steel scale interface under both O_2-N_2 and H_2O-N_2 atmospheres.As the oxidation proceeded,however,Cu enrichment at and its migration from the steel-scale interface were vastly different for different oxidizing atmospheres.In the case of O_2-N_2 oxidation,an oxide layer formed initially at the steel surface, but soon after a gap was developed at the steel-scale interface and grew in its size,which practically separated the scale from the steel substrate.The scale layer formed under this condition was porous.The Cu-rich phase initially formed at the interface was found migrating to the scale layer,leaving no Cu-rich phase at the interface.In the case of H_2O-N_2 oxidation,however,the scale layer formed was dense and tightly attached to the steel surface,and the Cu rich-phase continued to accumulate at the interface.Regarding the behavior of Cu-rich phase formed at the interface,it is proposed with experimental evidences that,when a gap forms at the steel-scale interface,it is the vaporization of Cu in the Cu-rich phase through the gap that brings Cu to the scale.