Purpose The purpose of this study was to study changes in choroidal thickness (ChT) and choroidal blood perfusion (ChBP), and the correlation between them, in guinea pig myopia. Methods The reliability of optical coherence tomography angiography (OCTA) for measuring ChT and ChBP was verified in guinea pigs, after cervical dislocation (n = 7) or temporal ciliary artery transection (n = 6). Changes in refraction, axial length, ChT, and ChBP were measured during spontaneous myopia (n = 9), monocular form-deprivation myopia (FDM, n = 13), or lens-induced myopia (LIM, n = 14), and after 4 days of recovery from FDM and LIM. Results The abolition (by cervical dislocation) or reduction (by temporal ciliary artery transection) of ChBP, and of the associated changes in ChT, were verified by OCTA, thus validating the method of measurement. In the spontaneous myopia group, ChT and ChBP were reduced by 25.2% and 31.9%, respectively. In FDM eyes, mean ± SD ChT and ChBP decreased significantly compared with the untreated fellow eyes (ChT fellow: 76.13 ± 9.34 μm versus 64.76 ± 11.15 μm for FDM; ChBP fellow: 37.87 ± 6.37 × 103 versus 30.27 ± 6.06 × 103 for FDM) and increased after 4 days of recovery (ChT: 77.94 ± 12.57 μm; ChBP: 37.41 ± 6.11 × 103). Effects of LIM were similar to those of FDM. Interocular differences in ChT and ChBP were significantly correlated in each group (FDM: R = 0.71, P < 0.001; LIM: R = 0.53, P < 0.001). Conclusions ChT and ChBP were significantly decreased in all three models of guinea pig myopia, and they both increased during recovery. Changes in ChT were positively correlated with changes in ChBP. Therefore, it is possible that the changes of ChT are responsible for the changes of ChBP or vice versa.

Changes in Choroidal Thickness and Choroidal Blood Perfusion in Guinea Pig Myopia.

Elizabethkingia meningoseptica: an important emerging pathogen causing healthcare-associated infections

Purpose To explore the association of choroidal vascularity and choriocapillaris blood perfusion with myopic severity in anisomyopes. Methods Refractive error, axial length (AL), and other biometric parameters were measured in 34 anisomyopic young adults. Macular choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI), were determined from swept-source optical coherence tomography (SS-OCT) vertical and horizontal B-scans. The percentage of choriocapillaris flow voids (FV%) was obtained from en face SS-OCT-angiography. Results The spherical equivalent refraction (SER) was -3.35 ± 1.25 diopters in the more myopic eyes and -1.25 ± 1.17 diopters in the less myopic eyes (P < 0.001). The interocular difference in SER was highly correlated with that in AL (P < 0.001). The macular ChT, TCA, LA, and SA were smaller in the more myopic eyes than in the less myopic eyes in both vertical and horizontal scans (all P < 0.001). Importantly, the CVIs in vertical and horizontal scans were smaller and the FV% was greater in the more myopic eyes (P < 0.05). In vertical scans, the interocular difference in CVIs was correlated with that in the SER, AL, and ChT (all P < 0.05). The interocular difference in FV% was correlated with that in SER, AL, and vertical and horizontal ChTs (all P < 0.05). Conclusions Choroidal vascularity and choriocapillaris blood perfusion were lower in the more myopic eyes of anisomyopic adults. These changes were correlated with the severity of myopia and choroidal thinning, indicating that choroidal blood flow is disturbed in human myopia.

/pdf/assessment-of-choroidal-vascularity-and-choriocapillaris-2c6ujdf89z.pdf

Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion in Anisomyopic Adults by SS-OCT/OCTA.

Myopia is the most common type of refractive errors characterized by excessive elongation of the ocular globe. With the increasing prevalence of myopia, improved knowledge of factors involved in myopia development is of particular importance. There are growing evidence suggesting that the choroid plays an important role in the regulation of eye growth and the development of myopia. Studies have demonstrated that thinning choroid is a structural feature of myopia, with a negative correlation between choroidal thickness and axial length, suggesting that the change in choroidal thickness may be a predictive biomarker for long-term changes in ocular elongation. Given the fact that the choroid is primarily a vascular structure capable of rapidly changing blood flow, variations of choroidal thickness might be primarily caused by changes in choroidal blood flow. Considering that hypoxia is associated with myopia and choroidal blood flow is the main source of oxygen and nourishment supply, apart from the effect on myopia possibly by changing choroidal thickness, decreasing choroidal blood flow may contribute to scleral ischaemia and hypoxia, resulting in alterations in the scleral structure and thus leading to myopia. This review aims to provide an overview of recent work exploring the influence of the choroid on myopia from perspectives of choroidal thickness and blood flow, which may present new predictive indicators for the onset of myopia and new targets for the development of novel therapeutic approaches for myopia.

The influence of the choroid on the onset and development of myopia: from perspectives of choroidal thickness and blood flow.

The purpose of the cross-sectional study is to describe the values and distribution of choroidal thickness and to explore its related factors, especially age, in Chinese children. A total of 3001 Chinese school children aged 6 to 19 years underwent comprehensive ophthalmic examinations, including axial length and cycloplegic refraction. Choroidal thickness was measured by swept-source optical coherence tomography (SS-OCT). There was a greater difference in the more central regions between the myopes and emmetropes. Multiple regression analysis was performed to determine the associated factors of choroidal thickness. The results demonstrated that age was independently positively related to choroidal thickness for emmetropes (β = 3.859, p < 0.001), and mild myopes with spherical equivalent greater than −2.00 D (−1.25 D < spherical equivalent ≤ −0.50 D: β = 3.476, p = 0.006; −2.00 D < spherical equivalent ≤ −1.25 D: β = 3.232, p = 0.020). However, no significant relationship between age and choroidal thickness was found in children with spherical equivalent ≤ −2.00 D, suggesting that the protective effect of physiologic choroidal growth with age against rapid axial elongation disappeared while axial elongation becomes the dominant determinant of choroidal thickness among children with myopia worse than −2.00 D.

/pdf/choroidal-thickness-in-3001-chinese-children-aged-6-to-19-1sx29dllpm.pdf

Choroidal Thickness in 3001 Chinese Children Aged 6 to 19 Years Using Swept-Source OCT.

Pulsatile ocular blood flow (POBF) determines the summed volume of blood entering the outer retina, choroid, and remaining uveal tract of the eye by measuring increases in intraocular pressure (IOP), with each heartbeat. POBF reflects the choroidal circulation, which is responsible for 85% of the POBF [1]. Other pulsatile components of pulse amplitude (OBFa), pulse volume (OBFv), and pulse rate (OBFr). OBFa indicates the amplitude of blood flow entering the eyeball. OBFv indicates the amount of blood entering the eyeball per each contraction of the heart. OBFr indicates the rate of ocular blood flow due to hear beat. This noninvasive assessment of ocular blood flow is based on analysis of the IOP pulse quantified by Perkins [2], utilizing a modified applanation prism with distensible film at the contact surface. Langham et al. [1] used a pneumotonometer to obtain a wave form of the ocular pulse, and subsequently derived values for POBF by assessing this wave form and its amplitude, together with the heart rate of subject. The pulsatile components of choroidal circulation are calculated from the ocular pulse wave produced by the bolus of blood entering the eye during cardiac systole. Because the eye is a closed compartment, volumetric blood changes are transferred to a pressure gradient, which is recorded by the pneumotonometer and linked to a blood flow analyzer (BFA). Measurements of POBF using this system have been found to give reproducible results [3,4]. Thus, POBF analysis is used for assessment of ocular vascular pathologies.

POBF has been evaluated in several ocular diseases, including glaucoma, retinitis pigmentosa, and age related macular degeneration [5,6,7]. Several authors have reported that factors such as age, heart rate, blood pressure, and axial length influence POBF [8,9,10,11]. Previous studies have reported that a relationship exists between the refractive error or axial length of the eye and POBF [11,12,13]. A study by Mori et al. [12] shows no correlation of refractive error with POBF, while a study by Benavente-Perez et al. [13] shows a positive correlation of refractive error with POBF.

In this study, we evaluate the pulsatile components of ocular blood flow (OBFa, OBFv, OBFr, and POBF) in healthy young human eyes, and determine choroidal blood flow changes in eyes with high myopia according to the pulsatile components of ocular blood flow analysis.

/pdf/choroidal-blood-flow-change-in-eyes-with-high-myopia-37xbnx35hx.pdf

Choroidal Blood Flow Change in Eyes with High Myopia.

To report keratitis with Elizabethkingia meningoseptica, which occurred in a healthy patient after wearing contact lenses for 6 months. A 24-year-old male patient visited our hospital with ocular pain. This patient had a history of wearing soft contact lenses for 6 months, about 10 hours per day. At initial presentation, slit lamp examination showed corneal stromal infiltrations and small epithelial defect. Microbiological examinations were performed from corneal scrapings, contact lenses, and the contact lens case and solution. The culture results from contact lenses, contact lens case and solution were all positive for Elizabethkingia meningoseptica. Thus, we could confirm that the direct cause of keratitis was contamination of the contact lenses. The patient was treated with 0.3% gatifloxacin. After treatment, the corneal epithelial defect was completely healed, and a slight residual subepithelial corneal opacity was observed. We diagnosed keratitis with Elizabethkingia meningoseptica in a healthy young male wearing soft contact lenses. We conclude that Elizabethkingia meningoseptica should be considered as a rare but potential pathogen for lens-related keratitis in a healthy host.

/pdf/keratitis-with-elizabethkingia-meningoseptica-occurring-1p9ndvuq9m.pdf

Keratitis with Elizabethkingia meningoseptica occurring after contact lens wear: a case report.

/pdf/utility-of-the-noncontact-specular-microscopy-for-15qm9dzhjo.pdf

Utility of the Noncontact Specular Microscopy for Measurements of Central Corneal Thickness

Utility of the Intraoperative Optical Coherence Tomography for Dense Vitreous Hemorrhage

PURPOSE To analyze the correlation between preoperative measurements of macular microstructures and aniseikonia after epiretinal membrane removal. METHODS This retrospective study included 32 eyes of 32 patients who underwent epiretinal membrane surgery and were followed up for 12 months. Spectral-domain optical coherence tomography was used to measure the thicknesses of the ganglion cell layer-inner plexiform layer, inner nuclear layer (INL), and outer retinal layer in macular microstructures. The new aniseikonia test was used to measure vertical and horizontal aniseikonia scores. RESULTS There was a significant decrease in central macular thickness and ganglion cell layer-inner plexiform layer thickness at 6 and 12 months postoperatively (all P < 0.001). Vertical aniseikonia scores, horizontal aniseikonia scores, and INL and outer retinal layer thicknesses did not show significant changes. Vertical aniseikonia scores and horizontal aniseikonia scores were significantly associated with INL thicknesses of each meridian at each follow-up time point (all P < 0.05). Preoperative vertical and horizontal INL thicknesses were correlated with vertical aniseikonia scores and horizontal aniseikonia scores at 12 months postoperatively (P = 0.014 and P = 0.002, respectively). CONCLUSION Aniseikonia values did not change after epiretinal membrane removal and were associated with INL thickness before and after surgery. Thus, preoperative INL thickness could be used as a predictor of surgical prognosis in epiretinal membrane patients.

Correlation between macular microstructures and aniseikonia after idiopathic epiretinal membrane removal.

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