Purpose Stereo vision tests are widely used in the clinical practice for screening amblyopia and amblyogenic conditions. According to literature, none of these tests seems to be suitable to be used alone as a simple and reliable tool. There has been a growing interest in developing new types of stereo vision tests, with sufficient sensitivity to detect amblyopia. This new generation of assessment tools should be computer based, and their reliability must be statistically warranted. The present study reports the clinical evaluation of a screening system based on random dot stereograms using a tablet as display. Specifically, a dynamic random dot stereotest with binocularly detectable Snellen-E optotype (DRDSE) was used and compared with the Lang II stereotest. Methods A total of 141 children (aged 4-14, mean age 8.9) were examined in a field study at the Department of Ophthalmology, Pécs, Hungary. Inclusion criteria consisted of diagnoses of amblyopia, anisometropia, convergent strabismus, and hyperopia. Children with no ophthalmic pathologies were also enrolled as controls. All subjects went through a regular pediatric ophthalmological examination before proceeding to the DRDSE and Lang II tests. Results DRDSE and Lang II tests were compared in terms of sensitivity and specificity for different conditions. DRDSE had a 100% sensitivity both for amblyopia (n = 11) and convergent strabismus (n = 21), as well as a 75% sensitivity for hyperopia (n = 36). However, the performance of DRDSE was not statistically significant when screening for anisometropia. On the other hand, Lang II proved to have 81.8% sensitivity for amblyopia, 80.9% for strabismus, and only 52.8% for hyperopia. The specificity of DRDSE was 61.2% for amblyopia, 67.3% for strabismus, and 68.6% for hyperopia, respectively. Conversely, Lang II showed about 10% better specificity, 73.8% for amblyopia, 79.2% for strabismus, and 77.9% for hyperopia. Conclusions The DRDSE test has a better sensitivity for the detection of conditions such as amblyopia or convergent strabismus compared with Lang II, although with slightly lower specificity. If the specificity could be further improved by optimization of the stimulus parameters, while keeping the sensitivity high, DRDSE would be a promising stereo vision test for screening of amblyopia.

Although development of binocularity is an extremely experience-dependent process, our data suggest that DRDC-VEP phase and P1 latency mature independently from visual experience. We propose that both the phase shift and decreasing P1 latency are indicators of myelination and increasingly faster signal transmission in the developing visual system.

Cells must protect their genome from harmful alterations, caused directly by DNA damage or indirectly by inappropriate repair, to avoid cell death or cancerous transformation. DNA double-strand (ds) breaks, the most severe type of DNA damage, are repaired in a potentially error-free manner by homologous recombination (HR). During HR, broken dsDNA ends are transformed into 3' single-stranded (ss) overhangs that form nucleoprotein filaments with recombinases. These filaments can search for intact, homologous dsDNA regions that serve as template for repair and can invade into the homologous DNA molecule to form a displacement loop (D-loop). D-loops are thus key HR DNAintermediate structures. D-loops are thought to be processed by multiple pathways with different outcomes and can serve as early decision points in HR regulation. Members of the RecQ helicase family are implicated both in D-loop stabilization and disruption. The human Bloom's syndrome RecQ helicase (BLM) is thought to channel HR into error-free pathways partially by processing D-loops. However, the exact mechanism of this action is poorly understood. Via a novel kinetic assay, here we show that the conserved domain architecture of BLM maintains an almost 1:1 balance in D-loop disruption and stabilization. Interestingly, the activity profile of BLM markedly differs from that of the very effective D-loop disruptor Escherichia coli RecQ. However, our single-molecule magnetic tweezers experiments reveal that the similar domain architecture of BLM and RecQ, while having different roles in D-loop processing, allows both proteins to sense DNA substrate geometry and unwind dsDNA in a repetitive fashion. Our results highlight how functions of the conserved architecture of RecQ helicases evolved to specialize these enzymes to different cellular requirements.

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