Background: A new commercially available optical low coherence reflectometry device (Lenstar, Haag-Streit or Allegro Biograph, Wavelight) provides high-resolution non-contact measurements of ocular biometry. The study evaluates the validity and repeatability of these measurements compared with current clinical instrumentation. Method: Measurements were taken with the LenStar and IOLMaster on 112 patients aged 41–96 years listed for cataract surgery. A subgroup of 21 patients also had A-scan applanation ultrasonography (OcuScan) performed. Intersession repeatability of the LenStar measurements was assessed on 32 patients Results: LenStar measurements of white-to-white were similar to the IOLMaster (average difference 0.06 (SD 0.03) D; p = 0.305); corneal curvature measurements were similar to the IOLMaster (average difference −0.04 (0.20) D; p = 0.240); anterior chamber depth measurements were significantly longer than the IOLMaster (by 0.10 (0.40) mm) and ultrasound (by 0.32 (0.62) mm; p<0.001); crystalline lens thickness measurements were similar to ultrasound (difference 0.16 (0.83) mm, p = 0.382); axial length measurements were significantly longer than the IOLMaster (by 0.01 (0.02) mm) but shorter than ultrasound (by 0.14 (0.15) mm; p<0.001). The LensStar was unable to take measurements due to dense media opacities in a similar number of patients to the IOLMaster (9–10%). The LenStar biometric measurements were found to be highly repeatable (variability ⩽2% of average value). Conclusions: Although there were some statistical differences between ocular biometry measurements between the LenStar and current clinical instruments, they were not clinically significant. LenStar measurements were highly repeatable and the instrument easy to use.

To develop a standardized questionnaire of near visual function and satisfaction to complement visual function evaluations of presbyopic corrections. Eye Clinic, School of Life and Health Sciences, Aston University, Midland Eye Institute and Solihull Hospital, Birmingham, United Kingdom. Questionnaire development. A preliminary 26-item questionnaire of previously used near visual function items was completed by patients with monofocal intraocular lenses (IOLs), multifocal IOLs, accommodating IOLs, multifocal contact lenses, or varifocal spectacles. Rasch analysis was used for item reduction, after which internal and test-retest reliabilities were determined. Construct validity was determined by correlating the resulting Near Activity Visual Questionnaire (NAVQ) scores with near visual acuity and critical print size (CPS), which was measured using the Minnesota Low Vision Reading Test chart. Discrimination ability was assessed through receiver-operating characteristic (ROC) curve analysis. One hundred fifty patients completed the questionnaire. Item reduction resulted in a 10-item NAVQ with excellent separation (2.92), internal consistency (Cronbach α = 0.95), and test-retest reliability (intraclass correlation coefficient = 0.72). Correlations of questionnaire scores with near visual acuity (r = 0.32) and CPS (r = 0.27) provided evidence of validity, and discrimination ability was excellent (area under ROC curve = 0.91). Results show the NAVQ is a reliable, valid instrument that can be incorporated into the evaluation of presbyopic corrections.

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 −5.0 D and +1.5 D were evaluated by using an absolute and relative depth-of-focus method, the direct comparison method, and a new “area-of-focus” 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 +1.00 diopter (D), −1.00 D, and −1.50 D and worse at −3.00 D, −3.50 D, −4.00 D, and −5.00 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 = 0.005) and the near zone was better with the diffractive (P = 0.020) and “mix and match” (P = 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 = 0.408, P = 0.010) and near zone (r _s = 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.

To evaluate the effect of reducing the number of visual acuity measurements made in a defocus curve on the quality of data quantified. Midland Eye, Solihull, United Kingdom. Evaluation of a technique. Defocus curves were constructed by measuring visual acuity on a distance logMAR letter chart, randomizing the test letters between lens presentations. The lens powers evaluated ranged between +1.50 diopters (D) and -5.00 D in 0.50 D steps, which were also presented in a randomized order. Defocus curves were measured binocularly with the Tecnis diffractive, Rezoom refractive, Lentis rotationally asymmetric segmented (+3.00 D addition [add]), and Finevision trifocal multifocal intraocular lenses (IOLs) implanted bilaterally, and also for the diffractive IOL and refractive or rotationally asymmetric segmented (+3.00 D and +1.50 D adds) multifocal IOLs implanted contralaterally. Relative and absolute range of clear-focus metrics and area metrics were calculated for curves fitted using 0.50 D, 1.00 D, and 1.50 D steps and a near add-specific profile (ie, distance, half the near add, and the full near-add powers). A significant difference in simulated results was found in at least 1 of the relative or absolute range of clear-focus or area metrics for each of the multifocal designs examined when the defocus-curve step size was increased (P<.05). Faster methods of capturing defocus curves from multifocal IOL designs appear to distort the metric results and are therefore not valid. No author has a financial or proprietary interest in any material or method mentioned.

To evaluate distance and near image quality after hybrid bi-aspheric multifocal central presbyLASIK treatments. Consecutive case series. Sixty-four eyes of 32 patients consecutively treated with central presbyLASIK were assessed. The mean age of the patients was 51 ± 3 years with a mean spherical equivalent refraction of -1.08 ± 2.62 diopters (D) and mean astigmatism of 0.52 ± 0.42 D. Monocular corrected distance visual acuity (CDVA), corrected near visual acuity (CNVA), and distance corrected near visual acuity (DCNVA) of nondominant eyes; binocular uncorrected distance visual acuity (UDVA); uncorrected intermediate visual acuity (UIVA); distance corrected intermediate visual acuity (DCIVA); and uncorrected near visual acuity (UNVA) were assessed pre- and postoperatively. Subjective quality of vision and near vision was assessed using the 10-item Rasch-scaled Quality of Vision and Near Activity Visual Questionnaire, respectively. At 1 year postoperatively, 93% of patients achieved 20/20 or better binocular UDVA; 90% and 97% of patients had J2 or better UNVA and UIVA, respectively; 7% lost 2 Snellen lines of CDVA; Strehl ratio reduced by ∼-4% ± 14%. Defocus curves revealed a loss of half a Snellen line at best focus, with no change for intermediate vergence (-1.25 D) and a mean gain of 2 lines for near vergence (-3 D). Presbyopic treatment using a hybrid bi-aspheric micro-monovision ablation profile is safe and efficacious. The postoperative outcomes indicate improvements in binocular vision at far, intermediate, and near distances with improved contrast sensitivity. A 19% retreatment rate should be considered to increase satisfaction levels, besides a 3% reversal rate.

To assess the validity and repeatability of the Aston Halometer. University clinic, United Kingdom. Prospective, repeated-measures experimental study. The halometer comprises a bright light-emitting-diode (LED) glare source in the center of an iPad4. Letters subtending 0.21° (~0.3 logMAR) were moved centrifugally from the LED in 0.05 degree steps in 8 orientations separated by 45 degrees for each of 4 contrast levels (1000, 500, 100, and 25 Weber contrast units [Cw]) in random order. Bangerter occlusion foils were inserted in front of the right eye to simulate monocular glare conditions in 20 subjects (mean age 27.7 ± 3.1 years). Subjects were positioned 2 meters from the screen in a dark room with the iPad controlled from an iPhone via Bluetooth operated by the researcher. The C-Quant straylight meter was also used with each of the foils to measure the level of straylight over the retina. Halometry and straylight repeatability was assessed at a second visit. Halo size increased with the different occlusion foils and target contrasts (F = 29.564, P < .001) as expected and in a pattern similar to straylight measures (F = 80.655, P < 0.001). Lower contrast letters showed better sensitivity but larger glare-obscured areas, resulting in ceiling effects caused by the screen's field-of-view, with 500 Cw being the best compromise. Intraobserver and interobserver repeatability of the Aston Halometer was good (500Cw: 0.84 to 0.93 and 0.53 to 0.73) and similar to the straylight meter. The halometer provides a sensitive, repeatable way of quantifying a patient-recognized form of disability glare in multiple orientations to add objectivity to subjectively reported discomfort glare.