Effect of position of near addition in an asymmetric refractive multifocal intraocular lens on quality of vision

Purpose
To evaluate the impact of the position of an asymmetric multifocal near segment on visual quality.

Setting
Cathedral Eye Clinic, Belfast, United Kingdom.

Design
Retrospective comparative case series.

Methods
Data from consecutive patients who had bilateral implantation of the Lentis Mplus LS-312 multifocal intraocular lens were divided into 2 groups. One group received inferonasal near-segment placement and the other, superotemporal near-segment placement. A +3.00 diopter (D) reading addition (add) was used in all eyes. The main outcome measures included uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), contrast sensitivity, and quality of vision. Follow-up was 3 months.

Results
Patients ranged in age from 43 to 76 years. The inferonasal group comprised 80 eyes (40 patients) and the superotemporal group, 76 eyes (38 patients). The mean 3-month spherical equivalent was −0.11 D ± 0.49 (SD) in the inferonasal group and −0.18 ± 0.46 D in the superotemporal group. The mean postoperative UDVA was 0.14 ± 0.10 logMAR and 0.18 ± 0.15 logMAR, respectively. The mean monocular UNVA was 0.21 ± 0.14 logRAD and 0.24 ± 0.13 logRAD, respectively. No significant differences were observed in the higher-order aberrations, total Strehl ratio (point-spread function), or modulation transfer function between the groups. Dysphotopic symptoms measured with a validated quality-of-vision questionnaire were not significantly different between groups.

Conclusion
Positioning of the near add did not significantly affect objective or subjective visual function parameters.

Genotypic and phenotypic diversity of the noncapsulated Haemophilus influenzae:Adaptation and pathogenesis in the human airways

The human respiratory tract contains a highly adapted microbiota including commensal and opportunistic pathogens. Noncapsulated or nontypable Haemophilus influenzae (NTHi) is a human-restricted member of the normal airway microbiota in healthy carriers and an opportunistic pathogen in immunocompromised individuals. The duality of NTHi as a colonizer and as a symptomatic infectious agent is closely related to its adaptation to the host, which in turn greatly relies on the genetic plasticity of the bacterium and is facilitated by its condition as a natural competent. The variable genotype of NTHi accounts for its heterogeneous gene expression and variable phenotype, leading to differential host-pathogen interplay among isolates. Here we review our current knowledge of NTHi diversity in terms of genotype, gene expression, antigenic variation, and the phenotypes associated with colonization and pathogenesis. The potential benefits of NTHi diversity studies discussed herein include the unraveling of pathogenicity clues, the generation of tools to predict virulence from genomic data, and the exploitation of a unique natural system for the continuous monitoring of long-term bacterial evolution in human airways exposed to noxious agents. Finally, we highlight the challenge of monitoring both the pathogen and the host in longitudinal studies, and of applying comparative genomics to clarify the meaning of the vast NTHi genetic diversity and its translation to virulence phenotypes.

The timing and spatiotemporal patterning of Neanderthal disappearance

ThetimingofNeanderthal disappearanceandtheextent to whichthey overlapped with the earliest incoming anatomically modern humans (AMHs)inEurasia arekey questions inpalaeoanthropology1,2 .Deter- mining the spatiotemporal relationship between the two populations is crucial if we are to understand the processes, timing and reasons leading to the disappearance of Neanderthals and the likelihood of cultural and genetic exchange. Serious technical challenges, however, havehinderedreliable datingof the period,as theradiocarbonmethod reaches its limit at 50,000 years ago3 .Herewe apply improved accel- erator mass spectrometry 14C techniques to construct robust chro- nologies from 40 key Mousterian and Neanderthal archaeological sites, ranging fromRussia toSpain.Bayesianagemodellingwas used togenerate probability distributionfunctions todetermine the latest appearancedate.Weshowthat theMousterianendedby41,030–39,260 calibratedyears BP(at95.4%probability) acrossEurope.Wealsodem- onstrate that succeeding ‘transitional’ archaeological industries, one ofwhich has beenlinked withNeanderthals (Cha ˆtelperronian)4 ,end at a similar time. Our data indicate that the disappearance of Nean- derthals occurred at different times in different regions.Comparing the data with results obtained fromthe earliest datedAMHsites in Europe, associated with the Uluzzian technocomplex5 , allows us to quantify the temporal overlap between the two human groups. The results revealasignificantoverlap of 2,600–5,400years (at 95.4%prob- ability).This hasimportant implications formodels seeking toexplain the cultural, technological and biological elements involved in the replacement of Neanderthals byAMHs.Amosaic of populations in Europe during the Middle to Upper Palaeolithic transition suggests that there was ample time for the transmission of cultural and sym- bolic behaviours, as well as possible genetic exchanges, between the two groups.