Silicone oil as a corneal lubricant to reduce corneal edema and improve visualization during vitrectomy.

AIM: To evaluate the efficacy and safety of silicone oil (SO) as a corneal lubricant to improve visualization during vitrectomy. METHODS: Patients who underwent vitreoretinal surgery were divided into two groups. Group 1 was operated on with initial SO (Oxane 5700) as a corneal lubricant. Group 2 was operated on with initial lactated ringer's solution (LRS) and then replaced with SO as required. Fundus clarity was scored during the surgery. Fluorescein staining was performed to determine the damage to corneal epithelium. RESULTS: Totally 114 eyes of 114 patients were included. Single SO use maintained a clear cornea and provided excellent visualization of surgical image. In group 1, the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes. In group 2, corneal edema frequently occurred after initial LRS use. The fundus clarity was grade 3 in 19/69 eyes, 2 in 37/69 eyes and 1 in 13/69 eyes (P<0.05). SO was applied in 29 eyes of initial LRS use with subsequent corneal edema, which eliminated the corneal edema in 26 eyes. Corneal fluorescein staining score in group 1 was 0 in 28 eyes, 1 in 11 eyes and 2 in 6 eyes, and 40, 20 and 9, respectively, in group 2 (all P>0.05). CONCLUSION: The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.

Changes in choroidal hemodynamics of form-deprivation myopia in Guinea pigs.

PURPOSE: We studied changes in the choroid, particularly variation in blood flow, during the development of myopia. The hemodynamic mechanism in play remains unclear. We evaluated blood flow by quantitating indocyanine green (ICG) fluorescence in a guinea pig model of form-deprivation myopia. METHODS: Guinea pigs were divided into form-deprivation myopia (FDM) and normal control (NC) groups. Ocular biometric and choroidal hemodynamics parameters were quantitatively derived via ICG imaging, and included the maximal ICG fluorescence intensity (Imax), rising time (Trising), blood flow index (BFI), and mean transit time (MTT). RESULTS: Form deprivation was associated with significant interocular differences in terms of both refractive error and axial length. ICG fluorescence hemodynamic maps of fundal blood flow and vasculature density were evident. In deprived eyes, the fluorescence signals exhibited significantly longer Trising and MTT but lower Imax and BFI than fellow eyes and NC group. The interocular differences in terms of the ocular biometric and hemodynamic parameters were significantly correlated. Hemodynamic analysis of choriocapillaris lobules revealed weakened fluorescence intensity and prolonged arrival and filling times in deprived eyes. Form deprivation reduced the number of lobulated choriocapillaris structures. CONCLUSION: Form-deprivation myopia triggered changes in the hemodynamic and vascular network structures of the choroid and choriocapillaris. The ICG fluorescence imaging/analysis method provides a unique tool for further myopia research.

MicroRNA Profiling in the Aqueous Humor of Keratoconus Eyes.

Purpose: To identify differentially expressed (DE) microRNAs (miRNAs) in the aqueous humor (AH) of keratoconus (KC) eyes using next-generation sequencing and to explore whether DE miRNAs might play roles in KC pathophysiology. Methods: The small RNAs in the AH of 15 KC eyes and 15 myopia eyes (the control group) were sequenced on an Illumina NovaSeq 6000 platform. Gene Oncology and Kyoto Encyclopedia of Genes and Genome enrichment analyses were performed. Receiver operating characteristic curves were used to identify potential KC biomarkers. Results: We identified 204 miRNAs in the AH of the KC group and 200 in the AH of the control group. Fourteen miRNAs were differentially expressed between the two groups; four miRNAs were upregulated and 10 downregulated in KC AH. The possible pathways regulated by the DE miRNAs included antigen processing and presentation, endocytosis, mismatch repair, and Hippo signaling. The AH concentrations of miR-222-3p, miR-363-3p, and miR-423-5p exhibited areas under the curves of 1. Conclusions: We profiled the DE miRNAs of the AH of KC eyes. These miRNAs may be associated with KC pathogenesis and could serve as KC biomarkers. Translational Relevance: Data on aberrantly expressed miRNAs in KC combined with bioinformatics analyses suggest possible roles for specific miRNAs. The DE miRNAs may serve as diagnostic KC biomarkers.

A simple technique for suprachoroidal space injection of triamcinolone acetonide in treatment of macular edema.

AIM: To introduce a simple resistance controlled suprachoroidal space (SCS) injection technique using a disposable 30-gauge needle connected to a 1 mL syringe and evaluate the effectiveness and applicability of this technique in the treatment of macular edema. METHODS: A total of 20 patients with various types of macular edema were subjected to a resistance controlled SCS injection of triamcinolone acetonide (TA) with a disposable 30-gauge needle connected to a 1 mL syringe. This technique allows the easy and smooth injection of the TA only once the tip of the needle reached the potential SCS which was indicated by the lower resistance on the plunger. The main outcome measures were anterior segment spectral-domain optical coherence tomography (AS-OCT) measurements post-operation immediately and central subfield thickness (CST), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) measurements at 3mo post-operation. RESULTS: AS-OCT examination showed the expansion of the SCS near the injection site immediately after SCS injection. At three months of follow-up, as compared to the baseline, the mean CST was significantly decreased from 535.0±157.24 to 319.55±127.30 µm (P<0.001), the mean BCVA was significantly improved from 1.05±0.41 to 0.73±0.41 logMAR (P<0.001), and the mean IOP was not significantly different, from 15.05±2.54 to 15.85±3.60 mm Hg (P=0.185). Any complication related to the injection procedure including cataract, choroidal and retinal hemorrhage, retinal detachment, or endophthalmitis was not observed in this study. CONCLUSION: The simple and minimally invasive technique of SCS injection of TA with a disposable 30-gauge needle connected to a 1 mL syringe is useful and applicable for macular edema.

Artificial intelligence improves accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor for adult refractometry.

AIM: To evaluate the accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor (hICA) with artificial intelligence (AI) by comparing its refraction measurements to those recorded using hICA and a clinical table-mounted automatic refractor (TAR). METHODS: A cross-sectional study using three optometers, including hICA with or without AI and TAR, for refractometry of adults (aged 19-49 years old) with no signs of ocular disease or trauma in the absence of cycloplegia. Right and left eye refraction data were recorded, including the spherical equivalent (SE), diopter of spherical power (DS), diopter of cylindrical power (DC) decomposed into vectors J0 and J45, and measurement times. To avoid analytical difficulties associated with the interdependence of observations between eyes from the same individual, the Generalized Estimation Equation was used to compare the SE, DS, J0 and J45 measurements, and the times thereof, among the different groups. The intraclass correlation coefficient (ICC) and Spearman's rank correlation coefficient were used to evaluate correlations among the measurements recorded by the three different instruments. Bland-Altman were used to analyze the precision of the equipment by the agreement. RESULTS: A total of 70 patients (140 eyes; mean age: 31.37y; range: 19-49y) were assessed using refractometry. In a brightly lit environment, there was no significant difference between the mean SE recorded using TAR and that recorded using hICA with AI or without AI (both P>0.05). In an intense-light environment, hICA equipped with AI showed a better detection rate than without AI. Light intensity had a greater effect on dioptric measurements recorded using hICA without AI (P<0.001) than on those recorded using the one equipped with AI (P<0.05). Measurement times varied significantly between the different light intensities and instruments (P<0.05). CONCLUSION: For the normal human eyes, AI may improve the accuracy, efficiency, and reliability of measurements recorded using hICA in various light environments.