Effect of capsular tension ring implantation on capsular stability after phacoemulsification in patients with weak zonules: a randomized controlled trial. CTR implantation in cataract patients with weak zonules.

BACKGROUND: The use of capsular tension ring (CTR) implantation to treat cataract patients with weak zonules is still controversial. The aim of this study was to examine the effects of CTR implantation on capsular stability after phacoemulsification in patients with weak zonules, especially patients who have undergone pars plana vitrectomy (PPV) or those who suffer from severe myopia. METHODS: A total of 42 patients who underwent phacoemulsification and received an intraocular lens (IOL) were randomized to undergo CTR implantation or not. The control and CTR groups were compared in terms of uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (BCDVA), refractive prediction error, the area of anterior capsulorhexis, and IOL inclination angle. Follow-up visits were conducted postoperatively at 1 day, 1 week, 1 month and 3 months. Subgroup analyses were performed based on PPV and severe myopia. RESULTS: Surgery significantly improved UDVA and BCDVA to similar extents in CTR and control patients, and refraction prediction error was similar between the two groups at all follow-up times. At 3 months after surgery, the area of anterior capsulorhexis was significantly larger in CTR patients than in controls (p = 0.0199). These differences were also significant between the subgroups of patients with severe myopia. Vertical IOL inclination was less within CTR groups at 3 months after surgery, especially in patients with severe myopia (p = 0.0286). At 1 week postoperatively, the proportion of individuals whose posterior lens capsule that had completely adhered to the posterior IOL surface was significantly higher among CTR patients (p = 0.023). No serious surgical complications were observed. CONCLUSION: CTR implantation can benefit cataract patients with weak zonules by maintaining the shape of the capsular bag, reducing capsule shrinkage and stabilizing IOL inclination. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-INR-17011217 , date of registration April 22, 2017, prospectively registered.

Comparison of pop-out responses to luminance and motion contrasting stimuli of tectal neurons in pigeons.

The emergence of visual saliency has been widely studied in the primary visual cortex and the superior colliculus (SC) in mammals. There are fewer studies on the pop-out response to motion direction contrasting stimuli taken in the optic tectum (OT, homologous to mammalian SC), and these are mainly of owls and fish. To our knowledge the influence of spatial luminance has not been reported. In this study, we have recorded multi-units in pigeon OT and analyzed the tectal response to spatial luminance contrasting, motion direction contrasting, and contrasting stimuli from both feature dimensions. The comparison results showed that 1) the tectal response would pop-out in either motion direction or spatial luminance contrasting conditions. 2) The modulation from motion direction contrasting was independent of the temporal luminance variation of the visual stimuli. 3) When both spatial luminance and motion direction were salient, the response of tectal neurons was modulated more intensely by motion direction than by spatial luminance. The phenomenon was consistent with the innate instinct of avians in their natural environment. This study will help to deepen the understanding of mechanisms involved in bottom-up visual information processing and selective attention in the avian.

Surgical management of intraocular lens dislocation: A meta-analysis.

PURPOSE: To compare the efficacy and safety of intraocular lens (IOL) repositioning and IOL exchange for the treatment of patients with IOL dislocation. METHODS: We systematically searched for relevant publications in English or Chinese in MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, WHO International Clinical Trial Registration Platform, Clinical Trial.gov, China Biology Medicine Database, China National Knowledge Infrastructure Database and grey literature sources. Study quality was assessed using the STROBE template for observational studies and the Cochrane template for randomized controlled trials (RCTs). Data were meta-analyzed using RevMan 5.3. RESULTS: The review included 14 English-language studies reporting 1 RCT and 13 retrospective case series involving 1,082 eyes. Average follow-up time was 13.7 months. Pooled analysis of 10 studies showed that the two procedures had a similarly effect on best corrected visual acuity (MD -0.00, 95%CI: -0.08 to 0.08, P = 0.99). Pooled analysis of nine studies showed no significant difference in incidence of IOL redislocation (RR 2.12, 95%CI 0.85 to 5.30, P = 0.11); pooled analysis of seven studies showed greater extent of incidence of cystoid macular edema in IOL exchange (RR 0.47, 95%CI 0.21 to 1.30, P = 0.06). Pooled analysis of three studies showed greater extent of incidence of anterior vitrectomy in IOL exchange (RR 0.11, 95%CI 0.04 to 0.33, P<0.0001). Pooled analysis of two studies showed greater postoperative spherical equivalents in IOL repositioning (MD 1.02, 95%CI 0.51 to 1.52, P<0.0001). pooled analysis suggested no significant differences between the two procedures in terms of intraocular pressure, endothelial cell density, surgically induced astigmatism, or incidence of retinal detachment, intraocular hemorrhage or pupillary block. CONCLUSION: IOL repositioning and exchange are safe and effective procedures for treating IOL dislocation. Neither procedure significantly affects best corrected visual acuity and IOL redislocation. IOL exchange was superior to repositioning in terms of postoperative SE, but IOL repositioning was associated with lower incidence of anterior vitrectomy, potentially lower incidence of cystoid macular edema.