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Femtosecond laser-assisted cataract surgery(FLACS)has been used for more than 10 years, with its safety and precision well-verified. In recent years, FLACS has been gradually applied to patients with glaucoma and cataracts, especially those patients with primary angle closure glaucoma(PACG). The unique anatomical characteristics of PACG increase the difficulty of lens extraction and potential complications in conventional phacoemulsification surgery, highlighting the distinct advantages of FLACS in these patients. Recently, the application of FLACS combined with minimally invasive glaucoma surgery(MIGS)in patients with open angle glaucoma, and goniosynechialysis(GSL)in patients with angle-closure glaucoma, and even in patients with filtering blebs after anti-glaucoma surgery, has been reported. The indications for FLACS are increasingly expanding. FLACS can cause a transient intraoperative increase in intraocular pressure(IOP), and ocular parameters can have a certain impact on IOP. The long-term effects on IOP require further research. More attention should be paid to the impact of FLACS on visual function in glaucoma patients and the related complications that may arise. This article reviews the application of FLACS in different types of glaucoma, its effects on IOP and visual function, specific complications, and application prospects.

To summarize the design and methodology of a trial designed to evaluate the efficacy and safety of low dose laser cycloplasty (LCP) in treating malignant glaucoma. Prospective, multicentre, non-controlled clinical trial. Subjects were recruited from eight ophthalmic centers in China. The target sample size was 34. Patients aged >18 years with a clinical diagnosis of malignant glaucoma inadequately controlled on medical therapy or malignant glaucoma recurrence after topical cycloplegics withdrawal were enrolled. All patients underwent LCP under retrobulbar anesthesia or sub-Tenon anesthesia. LCP is a treatment adopting few laser points (1100–2000 mW energy, 2000 milliseconds duration) that cauterizes and remodels the ciliary body over two clock hour-positions, which may relieve the ciliary ring block. Follow-up is planned for a period of 12 months. The primary outcome is the resolution of malignant glaucoma which is defined as central anterior chamber deepening after LCP. The Malignant Glaucoma Treatment trial (MGTT) will be the first prospective trial providing evidence of a treatment for malignant glaucoma. It intends to provide clinicians an optional, easy and convenient treatment for malignant glaucoma patients. Detailed morphological and biometric information collected during the study period will also help provide experience for the outcomes of malignant glaucoma. ChiCTR1800017960. [ABSTRACT FROM AUTHOR]

The training-based scheme constitutes an efficient method for noncoherent multiantenna communications. In this paper, we propose a superimposed training-based linear dispersion (STLD) transmission scheme, where the transmitted symbols are superposition of the training pilots and the data symbols. The STLD system enjoys simple encoding and efficient suboptimal decoding. Since for noncoherent multiple-input multiple-output systems employing the STLD scheme, analytical expressions of block- or bit-error probabilities do not exist, deterministic optimization methods cannot be used to design the optimal STLD system. We therefore propose to design the optimal STLD systems using simulation-based optimization techniques, together with gradient estimation. Simulation results show that with either maximum-likelihood or suboptimal decoding, the STLD systems obtained by the proposed design algorithm generally outperform the conventional training-based scheme employing space--time codes designed for coherent channels. Index Terms--Gradient estimation, linear dispersion (LD) codes, multiple-input multiple-output (MIMO), simulation-based optimization, training-based scheme.

A design scheme for linear dispersion (LD) codes that directly minimizes the block error rate (BLER) in multiple-input multiple-output (MIMO) channels with arbitrary fading statistics and various detection algorithms is presented, and a simulation-based optimization methodology for the design of LD codes through stochastic approximation is proposed. Simulation results show that codes designed by the proposed design paradigm outperform the codes designed based on algebraic number theory.

We derive the exact pairwise error probability (PEP) for space-time coding over quasi-static Rayleigh fading channels in the presence of spatial fading correlation. We show that receive correlation always degrades the PEP for all signal-to-noise ratios (SNRs). We quantify the effect of receive correlation by employing the notion of "majorization." We show that the stronger the receive correlation, the worse the PEP for all SNRs. We show that at low SNR, depending on the codes, transmit correlation can either improve or degrade the PEP performance. We show that to guarantee robust performance for arbitrary transmit correlation, the minimum eigenvalue of the codeword pair difference matrix should be maximized among all codeword pairs. Index Terms--Majorization, pairwise error probability (PEP), space-time coding, spatial correlation.

In this letter, based on the exact pairwise-error probability, we derive the union bound on the symbol-error probability (SEP) of the differential unitary space-time (DUST) modulation employing group codes. Instead of using the rank-and-determinant or Euclidean distance criteria, we optimize the cyclic group codes such that the union bound on the SEP is minimized for a predetermined scenario, taking into account the number of transmit and receive antennas and the operating signal-to-noise ratio (SNR). Our simulation results show that for a wide range of SNRs, the codes with the minimum union bound for a particular SNR outperform the codes designed based on rank-and-determinant or Euclidean distance criteria. Index Terms--Cyclic group codes, differential unitary space-time (DUST) coding, pairwise-error probability (PEP), union bound.

Objective: The aim of this study was to determine the prevalence of preoperative dry eye disease and evaluate tear film function in refractive surgery candidates in China. Methods: In this prospective noninterventional cross-sectional study, refractive surgical candidates from 13 preselected eye hospitals in China were recruited from July 2015 to February 2016. Patient histories, subjective symptoms, tear film breakup time (TBUT), ocular surface fluorescein staining, and Schirmer I tests (SIT), were assessed to conduct subgroup analysis. Results: A total of 1,849 patients were recruited, 41.4% were diagnosed with dry eye disease (766/1,849) and 44.9% (830/1,849) of subjects had a positive history of contact lens (CL) wear. The overall mean TBUT and SIT values were 7.3 ± 3.7 s and 15.2 ± 8.8 mm, respectively. The total prevalence of ocular surface fluorescein staining was 23.46% (422/1,849); 44.62% of patients had TBUT <5 s and 23.20% of patients had SIT <5 mm. CL wearers were observed to have a higher prevalence of dry eye than non-CL wearers (54.1 vs. 35.2%, OR = 2.17, 95% CI: 1.77–2.65). Conclusions: In this study, the most common abnormal finding in dry eye disease was tear film instability. A high proportion of refractive surgery candidates have preexisting dry eye disease and a history of CL wear prior to surgery. Careful attention should be given to the evaluation of preoperative dry eye in refractive surgery candidates. [ABSTRACT FROM AUTHOR]