Corneal endothelial ring following the implantation of toric implantable collamer lenses with a central hole: a case report.

BACKGROUND: To report a case of a corneal endothelial ring after toric implantable collamer lens (TICL, V4C) implantation in the right eye of a patient. CASE PRESENTATION: A 36-year-old woman with refractive errors of -8.00 DS/-2.00 DC * 8° in the right eye and - 6.50 DS/-1.75 DC * 177° in the left eye developed a corneal endothelial ring in the right eye on the first day after receiving TICLs implantation for treatment of high myopic astigmatism, which has not been previously reported as a complication of ICLs implantation. At 1 day postoperatively, the uncorrected distance visual acuity (UDVA) was 20/16, the intraocular pressure as measured by non-contact tonometry was 16.9 mmHg, and the vault as measured by anterior segment optical coherence tomography was 1238 µm. The eye was quiet and there was no unusual anterior chamber reaction. However, slit-lamp examination revealed an endothelial annular lesion of approximately 0.4 mm in diameter in the central part of the cornea, which was gray-white in color. The shape of the ring was the same as that of the central hole of the TICL. Specular microscopy showed that the mean endothelial cell density (ECD) of the ring significantly decreased to 1442 ± 263 cells/mm2, while the other part was still normal (2852 ± 103 cells/mm2). After 9 days of corticosteroid treatment and intense lubrication, the patient had a clear cornea, increased ECD (1532 ± 653 cells/mm2), and a good UDVA (20/16). CONCLUSION: This case suggests that a few hours after ICL V4C implantation, with a large vault, corneal displacement caused by an air puff would make the endothelium close to or even contact the ICL, producing a corneal endothelial ring. After ruling out various possible factors, we speculated that the endothelial ring was developed due to the non-contact tonometer air puff before slit-lamp evaluation, and this phenomenon was recorded by Corvis, which confirmed that the cornea could come in contact with the ICL due to gas shock. This "contact" may cause transient corneal endothelial damage.

Modified Technique for Small-Incision Lenticule Extraction: Ye's Swing Technique.

INTRODUCTION: This study aimed to evaluate the lenticule integrity and refractive outcomes of a new technique, Ye's swing technique, during small-incision lenticule extraction (SMILE). METHODS: This prospective study enrolled patients who underwent the SMILE procedure using a modified technique for lenticule dissection. Per the standard SMILE procedure, the cap cut was opened using a hook, and an anterior dissection was performed with a counterclockwise swing, from 8 to 12 o'clock. A posterior dissection was then performed by swinging counterclockwise, leaving a thin band of the peripheral rim undissected, from 8 to 4 o'clock. The counterclockwise swing was continued to separate the edges of the rim from 4 to 12 o'clock, after which microforceps were used to extract the lenticules. The primary outcome measures were safety and lenticule integrity at the end of the surgery, and the secondary outcome measure was efficacy. Changes in the ocular parameters from the preoperative visit to 1 month postoperative, including uncorrected and corrected distance visual acuity, manifest refraction, lenticule quality, and lenticule residual, were assessed using optical coherence tomography. RESULTS: A total of 246 patients (490 eyes) with myopia and myopic astigmatism were included in the present study. The dissected lenticules ranged in size from 52 to 148 µm. Postoperatively, the lenticule was completely and successfully extracted in all cases. There was no incisional edge tearing during lenticule separation. CONCLUSIONS: Ye's swing technique is a safe and effective procedure for lenticule dissection and refractive outcomes. We have now adopted this technique as our routine method for performing the SMILE procedure.

Comparison of Astigmatic Correction With and Without Cross-axis Alignment During Small Incision Lenticule Extraction.

PURPOSE: To compare clinical outcomes after astigmatism correction via small incision lenticule extraction (SMILE) with and without cross-axis alignment. METHODS: This prospective study included patients who underwent SMILE with astigmatism of greater than 0.75 diopters (D). In the alignment group, head position was readjusted by cross-axis alignment before the standard SMILE procedure. First, the cross-axis was aligned to corresponding green lines on the headrest. Then, the patient's head was adjusted to align the horizontal line to the outer canthus of both eyes and align the vertical line connecting the midpoints of the eyebrows and the bridge of the nose. Changes in ocular parameters were assessed, and vector analysis was performed 6 months postoperatively. RESULTS: The alignment and control groups included 61 and 54 eyes, respectively. Postoperatively, the safety and efficacy indices were comparable between the two groups. Notably, refractive cylinder differed significantly in the alignment group (-0.23 ± 0.26 D) compared to the control group (-0.36 ± 0.26 D) (P = .007). Forty-eight (78.7%) and 32 (59.3%) eyes in the alignment and control groups (P = .03) achieved an angle of error within ±5°, respectively. Vector analysis showed a significantly lower difference vector and a significantly better index of success in the alignment group than that in the control group (0.24 ± 0.25 vs 0.35 ± 0.24, P = .003 and 0.20 ± 0.22 vs 0.29 ± 0.22, P = .02, respectively). Moreover, the change in corneal trefoil differed significantly between the groups (P < .001). CONCLUSIONS: Cross-axis alignment for head positioning in SMILE significantly minimizes axis misalignment and reduces undercorrection astigmatism in myopic astigmatism correction. This technique is a non-invasive and effective method, especially for beginners. [J Refract Surg. 2022;38(10):624-631.].

Association between maternal thallium exposure and risk of gestational diabetes mellitus: Evidence from a birth cohort study.

BACKGROUND: The adverse effects of TI exposure on pregnant women are still unclear, especially regarding the risk of gestational diabetes mellitus (GDM) Objective: We explored the association between maternal urinary Tl burden and the risk of GDM. METHODS: A subsample of 1789 pregnant women were enrolled who provided spot urine samples before the diagnostic 75-g oral glucose tolerance test. Urinary Tl concentration was measured using inductively coupled plasma mass spectrometry. Logistic regression and covariance analysis were carried out to estimate the association between Tl exposure and GDM risk. RESULTS: The median of urinary Tl concentration was 0.382 µg/L or 0.525 µg/g creatinine (CC-Tl). There were 437 (24.4%) participants who were diagnosed with GDM, and the urinary CC-Tl concentrations of pregnant women with GDM were higher than that of pregnant women without GDM [0.548 (0.402, 0.788) vs 0.518 (0.356, 0.724), p = 0.014]. After adjusting for the relevant covariates, an association between urinary Tl concentrations and GDM was found. In comparison to the pregnant women in the lowest quartile of urinary CC-Tl concentration, the pregnant women in the highest quartile had a higher risk of GDM [OR (95% CI) = 1.44 (1.03, 2.02), p-trend = 0.055]. If limited to the pregnant women without family history of diabetes, the results were still robust [OR (95% CI) = 1.59 (1.11, 2.30), p-trend = 0.012]. CONCLUSION: Urinary CC-Tl concentration was associated with GDM among Chinese pregnant women. Our findings provide evidence that moderately high Tl exposure may be a novel risk factor for pregnant women health.

Mitochondrial tRNAAla 5601C>T variant may affect the clinical expression of the LHON­related ND4 11778G>A mutation in a family.

Certain mutations in mitochondrial DNA (mtDNA) are associated with Leber's hereditary optic neuropathy (LHON). In particular, the well­known NADH dehydrogenase 4 (ND4) m.11778G>A mutation is one of the most common LHON­associated primary mutations worldwide. However, how specific mtDNA mutations, or variants, affect LHON penetrance is not fully understood. The aim of the current study was to explore the relationship between mtDNA mutations and LHON, and to provide useful information for early detection and prevention of this disease. Following the molecular characterization of a Han Chinese family with maternally inherited LHON, four out of eight matrilineal relatives demonstrated varying degrees of both visual impairment and age of onset. Through PCR amplification of mitochondrial genomes and direct Sanger sequencing analysis, a homoplasmic mitochondrial­encoded ND4 m.11778G>A mutation, alongside a set of genetic variations belonging to human mtDNA haplogroup B5b1 were identified. Among these sequence variants, alanine transfer RNA (tRNA)Ala m.5601C>T was of particular interest. This variant occurred at position 59 in the TψC loop and altered the base pairing, which led to mitochondrial RNA (mt­RNA) metabolism failure and defects in mitochondrial protein synthesis. Bioinformatics analysis suggested that the m.5601C>T variant altered tRNAAla structure. Therefore, impaired mitochondrial functions caused by the ND4 m.11778G>A mutation may be enhanced by the mt­tRNAAla m.5601C>T variant. These findings suggested that the tRNAAla m.5601C>T variant might modulate the clinical manifestation of the LHON­associated primary mutation.

Characterization of inflammatory factor-induced changes in mesenchymal stem cell exosomes and sequencing analysis of exosomal microRNAs.

BACKGROUND: Treatments utilizing stems cells often require stem cells to be exposed to inflammatory environments, but the effects of such environments are unknown. AIM: To examine the effects of inflammatory cytokines on the morphology and quantity of mesenchymal stem cell exosomes (MSCs-exo) as well as the differential expression of microRNAs (miRNAs) in the exosomes. METHODS: MSCs were isolated from human umbilical tissue by enzymatic digestion. Exosomes were then collected after a 48-h incubation period in a serum-free medium with one of the following the inflammatory cytokines: None (control), vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor (TNF) α, and interleukin (IL) 6. The morphology and quantity of each group of MSC exosomes were observed and measured. The miRNAs in MSCs-exo were sequenced. We compared the sequenced data with the miRBase and other non-coding databases in order to detect differentially expressed miRNAs and explore their target genes and regulatory mechanisms. In vitro tube formation assays and Western blot were performed in endothelial cells which were used to assess the angiogenic potential of MSCs-exo after inflammatory cytokine stimulation. RESULTS: MSCs-exo were numerous, small, and regularly shaped in the VCAM-1 group. TNFα stimulated MSCs to secrete larger and irregular exosomes. IL6 led to a reduced quantity of MSCs-exo. Compared to the control group, the TNFα and IL6 groups had more downregulated differentially expressed miRNAs, particularly angiogenesis-related miRNAs. The angiogenic potential of MSCs-exo declined after IL6 stimulation. CONCLUSION: TNFα and IL6 may influence the expression of miRNAs that down-regulate the PI3K-AKT, MAPK, and VEGF signaling pathways; particularly, IL6 significantly down-regulates the PI3K-AKT signaling pathway. Overall, inflammatory cytokines may lead to changes in exosomal miRNAs that abnormally impact cellular components, molecular function, and biological processes.

In vivo confocal microscopy of pre-Descemet's membrane corneal dystrophy.

Pre-Descemet's membrane corneal dystrophy is clinically characterized by the presence of numerous tiny pleomorphic opacities located in the deep stroma immediately anterior to Descemet's membrane. A 35-year-old man, clinically diagnosed with pre-Descemet's corneal dystrophy, was examined by in vivo slit scan confocal microscopy. The pleomorphic structures containing dense hyperreflective inclusions in the posterior stroma were revealed in vivo. To the best of the authors' knowledge, it is consistent with the result of the previous histological study, but different from other reports using in vivo confocal microscopy.