Xialin Liu

Torsional mode versus conventional ultrasound mode phacoemulsification: Randomized comparative clinical study

PURPOSE: To compare the intraoperative and short‐term postoperative outcomes of cataract surgery performed with torsional mode and conventional ultrasound mode using the Infiniti Vision System (Alcon Laboratories). SETTING: Cataract Service, Zhongshan Ophthalmic Center, Sun‐Yat‐Sen University, Guangzhou, China. METHODS: In this randomized comparative study, 525 eyes were assigned to phacoemulsification by torsional mode or conventional ultrasound (US) mode. The surgery was performed by an experienced surgeon, and the outcomes were evaluated by an examiner who was masked to treatment assignments. Primary outcome measures were US time (UST), cumulative dissipated energy (CDE), and surgical complications. Patients were seen 1, 7, and 30 days after surgery. Postoperative outcome measures were the final best corrected visual acuity (BCVA) and the change in corneal clarity, central corneal thickness (CCT), and endothelial cell count. RESULTS: The US group had 262 eyes and the torsional group, 263 eyes. All patients completed the follow‐up visits. In the eyes with nucleus density grades of 1, 2, 3, and 4, the mean UST was 10.25 seconds ± 7.4 (SD), 25.14 ± 5.5 seconds, 36.45 ± 8.3 seconds, and 61.44 ± 17.8, respectively, in the US group and 8.32 ± 6.8 seconds, 18.45 ± 7.2 seconds, 29.48 ± 12.4 seconds, and 48.39 ± 20.3 seconds, respectively, in the torsional group (P<.001); the mean CDE was 1.25 ± 0.5, 4.18 ± 1.2, 8.59 ± 6.5, and 16.51 ± 9.6, respectively, in the US group and 0.94 ± 0.3, 3.13 ± 2.7, 7.47 ± 12.6, and 14.08 ± 8.3, respectively, in the torsional group (P<.001). At 1 day and 7 days, the mean BCVA was 0.23 ± 0.12 logMAR and 0.00 ± 0.10 logMAR, respectively, in the US group and 0.18 ± 0.11 logMAR and −0.08 ± 0.05 logMAR, respectively, in the torsional group (P<.001). At 30 days, the mean BCVA was −0.10 ± 0.07 logMAR and −0.12 ± 0.06 logMAR in the US group and the torsional group, respectively (P>.01). At 1 day and 7 days, the mean CCT was 625 ± 80 μm and 568 ± 37 μm, respectively, in the US group and 601 ± 35 μm and 559 ± 40 μm, respectively, in the torsional group (P<.001). At 30 days, the mean CCT was 531 ± 30 μm in the US group and 529 ± 39 μm in the torsional group (P>.01). At 7 days and 30 days, the mean central corneal endothelial cell count was 2135 ± 858 cells/mm2 and 2084 ± 527 cells/mm2, respectively, in the US group and 2004 ± 656 cells/mm2 and 1953 ± 615 cells/mm2, respectively, in the torsional group (P<.001). CONCLUSION: The torsional mode may provide more effective lens removal with a lower level of phacoemulsification time and energy.

Torsional ultrasound modality for hard nucleus Phacoemulsification cataract extraction

Aim: To evaluate the efficacy and safety of phacoemulsification using torsional modality with different parameter settings for hard nucleus cataract extraction. Design: A prospective, randomised clinical study. Methods: A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to the Emery–Little system classification system, requiring phacoemulsification and intraocular lens implantation, was included. Eyes were randomly assigned to the Linear Torsional combined with Ultrasound power group (Linear Tor+US group, nu200a=u200a66), 100% Fixed Torsional group (Fixed Tor group, nu200a=u200a65) and conventional Ultrasound burst group (US group, nu200a=u200a67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op days 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts. Results: The mean UST was lower in the Fixed Tor group than in the US group and in the Lin US+Tor group (p⩽0.0001). The mean CDE was lower in the Lin Tor+US group and in the Fixed Tor group than in the US group (p⩽0.0001). Comparing with the two Tor group, the US group had a lower average BCVA on post-op 1, 7 (p⩽0.0001) and 30 (p>0.01), greater average central corneal and incisional thickness on days 1, 7 (p⩽0.0001) and 30 (p>0.01), and higher average corneal endothelial cell losses on day 7 and 30 days (p⩽0.0001). Conclusions: Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality.

Lens regeneration using endogenous stem cells with gain of visual function

The repair and regeneration of tissues using endogenous stem cells represents an ultimate goal in regenerative medicine. To our knowledge, human lens regeneration has not yet been demonstrated. Currently, the only treatment for cataracts, the leading cause of blindness worldwide, is to extract the cataractous lens and implant an artificial intraocular lens. However, this procedure poses notable risks of complications. Here we isolate lens epithelial stem/progenitor cells (LECs) in mammals and show that Pax6 and Bmi1 are required for LEC renewal. We design a surgical method of cataract removal that preserves endogenous LECs and achieves functional lens regeneration in rabbits and macaques, as well as in human infants with cataracts. Our method differs conceptually from current practice, as it preserves endogenous LECs and their natural environment maximally, and regenerates lenses with visual function. Our approach demonstrates a novel treatment strategy for cataracts and provides a new paradigm for tissue regeneration using endogenous stem cells.

Aberration and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens eyes

Background:u2002 Higher‐order aberrations and contrast sensitivity were evaluated in patients who underwent phacoemulsification cataract extraction followed by implantation of aspherical, monofocal or multifocal intraocular lens (IOL) replacements.

Early changes in clear cornea incision after phacoemulsification: an anterior segment optical coherence tomography study

Purpose:u2002 We aimed to investigate the ultrastructures of clear corneal incisions 24u2003hours after phacoemulsification using anterior segment optical coherence tomography (AS‐OCT).

Down regulation of the PEDF gene in human lens epithelium cells changed the expression of proteins vimentin and αB-crystallin

We demonstrated recently that opioid-induced activation of phospholipase D2 (PLD2) enhances μ- (MOPr) and δ-opioid receptor endocytosis/recycling and thus reduces the development of opioid receptor desensitization and tolerance. However, the mechanistic basis for the PLD2-mediated induction of opioid receptor endocytosis is currently unknown. Here we show that PLD2-generated phosphatidic acid (PA) might play a key role in facilitating the endocytosis of opioid receptors. However, PLD2-derived PA is known to be further converted to diacylglycerol (DAG) by PA phosphohydrolase (PPAP2). In fact, blocking of PA phosphohydrolase activity by propranolol or PPAP2-short interfering RNA (siRNA) transfection significantly attenuated agonist-induced opioid receptor endocytosis. The primary importance of PA-derived DAG in the induction of opioid receptor endocytosis was further supported by the finding that increasing the DAG level by inhibiting the reconversion of DAG into PA with the DAG kinase inhibitor 3-[2-(4-[bis-(4-fluorophenyl)methylene]-1-piperidinyl)ethyl]-2,3-dihydro-2-thioxo-4(1H)quinazolinone (R59949) or the addition of the synthetic cell-permeable DAG analog 1,2-dioctanoyl-sn-glycerol (DOG), further increased the agonist-induced opioid receptor endocytosis. Moreover, the addition of DOG bypasses the PLD2-siRNA- or PPAP2-siRNA-mediated impairment of DAG synthesis and resulted in a restoration of agonist-induced opioid receptor internalization. Further studies established a functional link between PA-derived DAG and the activation of p38 mitogen-activated protein kinase (MAPK) and the subsequent phosphorylation of the Rab5 effector early endosome antigen 1, which has been demonstrated recently to be required for the induction of MOPr endocytosis. Taken together, our results revealed that the regulation of opioid receptor endocytosis by PLD2 involves the conversion of its product PA to DAG resulting in an activation of the p38 MAPK pathway.

Role of anterior capsule polishing in residual lens epithelial cell proliferation

PURPOSE: To determine the role of anterior capsule polishing in residual lens epithelial cell (LEC) proliferation. SETTING: Zhongshan Ophthalmic Center, Sun Yat‐sen University, Guangzhou, China. METHODS: Phacoemulsification was performed on pairs of human cadaver eyes. One eye of each pair had anterior capsule polishing; the fellow eye did not. Capsular bags with implanted intraocular lenses (IOLs) were incubated in culture. Specimens were observed and photographed under microscopy. For clinical comparison, both eyes of patients who had phacoemulsification and IOL implantation with anterior capsule polishing in 1 eye only were observed for 1 year postoperatively. RESULTS: The study comprised 10 pairs of cadaver eyes and 20 eyes of 10 patients. One day after surgery, large patches of cells remained under the anterior capsule and the equatorial zone in the unpolished cadaver eyes and the anterior capsule was clear in the polished eyes. By 3 days in culture, many patches of dead cells had formed in the unpolished eyes. After 7 days in culture, cell growth was minimal in the unpolished eyes; however, robust cell proliferation was observed in the polished eyes. In the clinical comparison, there was no obvious difference in the mean subjectively assessed fibrotic posterior capsule opacification (PCO) score between polished eyes and unpolished eyes at 1 year. CONCLUSIONS: Anterior capsule polishing, although it removed many LECs, did not decrease residual cell growth and, conversely, enhanced cell proliferation in capsular bag cultures. This might explain why polishing does not reduce PCO in clinical studies. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Elevated serum IL-23 correlates with intraocular inflammation after cataract surgery in patients with Vogt–Koyanagi–Harada disease

Purpose Patients with Vogt–Koyanagi–Harada (VKH) disease are known to have severe inflammation after cataract surgery. This study was designed to investigate the role of IL-17-producing T helper (Th17) cell-related pro-inflammatory cytokines on postoperative inflammation in VKH patients. Methods Serum from nine VKH patients and nine controls with age-related or congenital cataract was collected before and 1, 7, 30 and 90u2005days after surgery, and aqueous humor (AqH) at the commencement of surgery. Protein levels of IL-23, IL-27, IL-17 and IFN-γ in serum and AqH were measured by ELISA. A laser flare-cell photometer was used to quantify intraocular inflammation. Results Serum IL-23 levels were significantly increased in VKH compared with control patients and peaked at 1u2005day postoperative, decreased rapidly in the first week, then attenuated gradually. In VKH patients, serum levels of IFN-γ were elevated in the first week after surgery and IL-27 was upregulated in the first month. Importantly, serum IL-23 levels were strongly correlated with aqueous flare value (r=0.689; p=0.007) and cell counts (r=0.671; p=0.01) in VKH compared with control patients. Conclusions The data indicate that serum IL-23 levels are significantly elevated in VKH compared with control patients and are strongly associated with postoperative intraocular inflammation.

Vasoprotective effect of PDGF-CC mediated by HMOX1 rescues retinal degeneration

Significance PDGF-CC plays critical roles in many biological processes, such as development, tumor growth, and angiogenesis. However, its role in blood vessel survival/regression and the underlying mechanisms remain unknown. Here, using different loss- and gain-of-function assays and multiple model systems, we show that PDGF-CC is a critical vascular protective factor required to maintain blood vessel survival. Mechanistically, we found that heme oxygenase-1 (HMOX1) activity is crucial for the vascular protective/survival effect of PDGF-CC. Given the general involvement of vascular degeneration in most degenerative diseases, PDGF-CC may be of therapeutic use in treating different types of degenerative disorders. Our findings point out that the PDGF-CC level should be monitored closely in various pathological conditions to ensure normal blood vessel survival. Blood vessel degeneration is critically involved in nearly all types of degenerative diseases. Therefore strategies to enhance blood vessel protection and survival are highly needed. In this study, using different animal models and cultured cells, we show that PDGF-CC is a potent vascular protective and survival factor. PDGF-CC deficiency by genetic deletion exacerbated blood vessel regression/degeneration in various animal models. Importantly, treatment with PDGF-CC protein not only increased the survival of retinal blood vessels in a model of oxygen-induced blood vessel regression but also markedly rescued retinal and blood vessel degeneration in a disease model of retinitis pigmentosa. Mechanistically, we revealed that heme oxygenase-1 (HMOX1) activity is critically required for the vascular protective/survival effect of PDGF-CC, because blockade of HMOX1 completely abolished the protective effect of PDGF-CC in vitro and in vivo. We further found that both PDGF receptors, PDGFR-β and PDGFR-α, are required for the vasoprotective effect of PDGF-CC. Thus our data show that PDGF-CC plays a pivotal role in maintaining blood vessel survival and may be of therapeutic value in treating various types of degenerative diseases.

Evaluation of corneal changes with accommodation in young and presbyopic populations using Pentacam High Resolution Scheimpflug system.

To evaluate the changes occurring in the cornea with accommodation in young and presbyopic people.