Search

Purpose Phoria measurements form a routine part of the examination of binocular vision. Various studies have compared different methods of phoria measurement and their repeatability between sessions. However, no studies have accounted for within-session repeatability, and few norms have been available to date. Our aims were to assess the short-term within-session repeatability, the agreement and the comparisons between three phoria tests and the delineation of normative data. Method The participants comprised 315 refractive corrected participants with a normal binocular vision, with ages between 20 and 80 years. Phoria was measured using three methods: von Graefe (VG), modified Thorington (MT) and Thorighton (TH) procedures. Each measurement was taken 3 consecutive times at far and near. Results The repeatability between measurements was high (0.87 to 0.96), but the relationship between tests was medium (0.407 to 0.682). About the mean bias, VG show more exo values (0.02 to 0.14 at far and 0.07 to 0.14 at near) and MT and TH similar values (−0.04 to 0.08 at far and −0.1 to 0.03 at near). The best agreement between tests was for TH and MT (LoA = 2.33 at far and LoA = 4.44 at near). Normative data for non-presbyopic were provided. Conclusion Overall, there is a high agreement between MT and TH. Conversely, VG shows more exo values at near and shows large limits of agreement. We recommend that subjective measurements of phoria can best be quantified once using the MT or TH techniques in free space and the values compared with updated norms.

Eye charts are typically optimized to assess visual acuity (VA) with constant and controlled spacing, while close-to-acuity crowding limits letter identification in the normal fovea when adjacent letters are closely spaced. Here we developed a clinical tool that enables the assessment of acuity with different levels of crowding. In a cross-sectional study, we examined the developmental trajectories with our newly devised Milan Eye Chart (MEC). A total of 252 children of 1st, 3rd and 5th grade were assessed with the MEC using SLOAN letter optotypes with 100%, 50%, 25% and 12.5% inter-optotype spacing. Results show an interaction between spacing and grade. The performance to the 100% standard VA was not significantly different among grades, while the narrow spaced acuity (12.5% spacing) strongly improved with the grade. The different trajectories of acuity measured with high spaced and low spaced eye-charts suggest that the mechanisms able to reduce the crowding effects develops later than VA, and it is, at least in part, dissociated by the psychophysiological development of lower level visual mechanisms. The MEC charts are feasible and useful in assessing visual acuity with different level of crowding during the whole lifespan. The opportunity to assess crowding-limited acuity in early age is particularly relevant since it plays a significant role in amblyopia screening.

The developmental eye movement (DEM) test is a practical and simple method for assessing and quantifying ocular motor skills in children. Different studies have previously assessed the reliability of the DEM test and they have generally found high values for vertical and horizontal time, whereas those for Ratio and Errors were medium and low, respectively. In the second application of test were found an improvement in performance in all subtests. Our aim was to evaluate the reliability of the DEM test using seconds and percentile scoring and looking in depth at the improvement in performance when the test is repeated. We tested the reliability of the DEM test on a group of 115 children from the 2nd to the 5th grade using different statistical methods: correlations, ANOVA, limits of agreement for results expressed in seconds and as percentile scoring and pass-fail diagnostic classification. We found high reliability with excellent values for vertical and adjusted horizontal time, medium-to-high for ratio and medium for errors. We have re-confirmed the presence of a significant improvement of performance on the second session for vertical time, horizontal time and ratio. The stability of binary classification of Pass-Fail criteria appears to be medium. We found high reliability for the DEM test when compared with the published results of other research but the improvement of performance, the learning effect was still present, but at a lower level than previously found. With the awareness of these limitations the DEM test can be used in clinical practice in evaluating performance over time.

Induced pluripotent stem cell (iPSC) technology has provided researchers with a unique tool to derive disease-specific stem cells for the study and possible treatment of degenerative disorders with autologous cells. The low efficiency and heterogeneous nature of reprogramming is a major impediment to the generation of personalized iPSC lines. Here, we report the generation of a lentiviral system based on a microRNA-regulated transgene that enables for the efficient selection of mouse and human pluripotent cells. This system relies on the differential expression pattern of the mature form of microRNA let7a in pluripotent versus committed or differentiated cells. We generated microRNA responsive green fluorescent protein and Neo reporters for specific labeling and active selection of the pluripotent cells in any culture condition. We used this system to establish Rett syndrome and Parkinson's disease human iPSCs. The presented selection procedure represents a straightforward and powerful tool for facilitating the derivation of patient-specific iPSCs.