PURPOSE. To determine the most appropriate analysis technique for the differentiation of multifocal intraocular lens (MIOL) designs by using defocus curve assessment of visual capability.METHODS. Four groups of 15 subjects were implanted bilaterally with either monofocal intraocular lenses, refractive MIOLs, diffractive MIOLs, or a combination of refractive and diffractive MIOLs. Defocus curves between À5.0 D and þ1.5 D were evaluated by using an absolute and relative depth-of-focus method, the direct comparison method, and a new ''area-offocus'' metric. The results were correlated with a subjective perception of near and intermediate vision. RESULTS.Neither depth-of-focus method of analysis was sensitive enough to differentiate between MIOL groups (P > 0.05). The direct comparison method indicated that the refractive MIOL group performed better at þ1.00 diopter (D), À1.00 D, and À1.50 D and worse at À3.00 D, À3.50 D, À4.00 D, and À5.00 D than did the diffractive MIOL group (P < 0.05). The area-of-focus intermediate zone was greater with the refractive than with the diffractive MIOL group (P ¼ 0.005) and the near zone was better with the diffractive (P ¼ 0.020) and ''mix and match'' (P ¼ 0.039) groups than with the refractive MIOL group. The subjective perception of intermediate and near vision agreed best with the area-of-focus metric for the intermediate (r s ¼ 0.408, P ¼ 0.010) and near zone (r s ¼ 0.484, P < 0.001).CONCLUSIONS. Conventional depth-of-focus metrics provide a single value to quantify the useful range of vision; however, they fail to provide sufficient detail to differentiate between MIOL designs. The direct comparison method provides a large amount of information, although the results can be complex to interpret. The proposed area-of-focus metric provides a simple, but differentiating method of evaluating MIOL defocus curves. (Invest Ophthalmol Vis Sci. 2012;53:3920-3926 Previous in vivo MIOL studies have examined the visual range of MIOLs by using measurements of visual acuity (VA) either at varying distances 4-6 or through different levels of spectacle lens defocus.7-9 However, the more physical method of measuring VA at varying distances is often impractical owing to the need to control angular image size and luminance.Measuring VA through a range of spectacle lenses creates a defocus curve profile. A previous study has suggested that VA measured with this method provides an underestimation of the true VA at the corresponding distance owing to the magnification effects of lenses in the spectacle plane (although this can be compensated for mathematically 10 ) and the disrupted natural associated convergence and pupil response. 11The two focal points created by the conventional bifocal MIOL result in a distinctive defocus curve profile with two peaks of optimum acuity: one at the distance focal point and the other at the near focus. 6 Hence, defocus curves demonstrate the strength of the near addition (the separation in diopters between the distance and near peak) as well as the quality of vis...

PRPF8-retinitis pigmentosa is said to be severe but there has been no overview of phenotype across different mutations. We screened RP patients for PRPF8 mutations and identified three new missense mutations, including the first documented mutation outside exon 42 and the first de novo mutation. This brings the known RP-causing mutations in PRPF8 to nineteen. We then collated clinical data from new and published cases to determine an accurate prognosis for PRPF8-RP. Clinical data for 75 PRPF8-RP patients were compared, revealing that while the effect on peripheral retinal function is severe, patients generally retain good visual acuity in at least one eye until the fifth or sixth decade. We also noted that prognosis for PRPF8-RP differs with different mutations, with p.H2309P or p.H2309R having a worse prognosis than p.R2310K. This correlates with the observed difference in growth defect severity in yeast lines carrying the equivalent mutations, though such correlation remains tentative given the limited number of mutations for which information is available. The yeast phenotype is caused by lack of mature spliceosomes in the nucleus, leading to reduced RNA splicing function. Correlation between yeast and human phenotypes suggests that splicing factor RP may also result from an underlying splicing deficit.

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