The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/ lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

Anterior segment optical coherent tomography (AS-OCT, Visante; Zeiss) is used to examine meridional variation in anterior scleral thickness (AST) and its association with refractive error, ethnicity and gender. Scleral cross-sections of 74 individuals (28 males; 46 females; aged between 18-40 years (27.7±5.3)) were sampled twice in random order in 8 meridians: [superior (S), inferior (I), nasal (N), temporal (T), superior-temporal (ST), superior-nasal (SN), inferior-temporal (IT) and inferior-nasal (IN)]. AST was measured in 1mm anterior-to-posterior increments (designated the A-P distance) from the scleral spur (SS) over a 6mm distance. Axial length and refractive error were measured with a Zeiss IOLMaster biometer and an open-view binocular Shin-Nippon autorefractor. Intra- and inter-observer variability of AST was assessed for each of the 8 meridians. Mixed repeated measures ANOVAs tested meridional and A-P distance differences in AST with refractive error, gender and ethnicity. Only right eye data were analysed. AST (mean±SD) across all meridians and A-P distances was 725±46μm. Meridian SN was the thinnest (662±57μm) and I the thickest (806±60μm). Significant differences were found between all meridians (p<0.001), except S:ST, IT:IN, IT:N and IN:N. Significant differences between A-P distances were found except between SS and 6 mm and between 2 and 4 mm. AST measurements at 1mm (682±48 μm) were the thinnest and at 6mm (818±49 μm) the thickest (p<0.001); a significant interaction occurred between meridians and A-P distances (p<0.001). AST was significantly greater (p<0.001) in male subjects but no significant differences were found between refractive error or ethnicity. Significant variations in AST occur with regard to meridian and distance from the SS and may have utility in selecting optimum sites for pharmaceutical or surgical intervention.

Increased CMT is associated with myopia. We speculate that the lack of correlation in myopic subjects between CMT and axial length, but not between CMT and OV, is evidence that disrupted feedback between the fovea and ciliary apparatus occurs in myopia development.

Background Keratometric methodology varies between instruments and the differences may have a clinical impact. We investigated the agreement and reproducibility of six keratometers. Methods Keratometry was performed on 100 subjects at two separate sessions with IOLMaster 500, Pentacam, OPD scanner, Medmont E300, Javal‐Schiøtz and TMS‐5. A second observer assessed 30 subjects to determine inter‐observer variability. A single individual was assessed on 10 separate sessions to determine intra‐observer variability. Data were analysed using coefficient of variation (CV) and intra‐class correlation coefficient (ICCC) for intra‐observer variation. Inter‐observer concordance was evaluated by the ICCC. Bland–Altman plots, Pearson's correlation coefficient and repeated measures analysis of variance were used to assess agreement of data produced by the instruments. Results OPD scanner and Javal‐Schiøtz mean spherical equivalent (MSE) results were systematically different (p < 0.001) from other instruments (flatter and steeper, respectively). J0/J45 were similar for all instruments (p < 0.05). Bland–Altman comparison plots indicated that Pentacam and IOLMaster demonstrated greatest level of agreement (ICC results MSE = 0.992, J0 = 0.934 and J45 = 0.890). Agreement (ICC) between observers for MSE ranged from 0.955 to 0.995 for all instruments; lower levels of agreement were found for J0/J45 (0.289 to 0.901). IOLMaster showed greatest correlation and Medmont the lowest. All instruments showed high intra‐observer repeatability of MSE (CV 0.1 to 0.3 per cent). The J0/J45 readings showed greater variability (CV range 8.8 to 57.6 per cent). Conclusion When considering MSE alone IOLMaster, Pentacam, OPD scan and Medmont may be considered interchangeable; however, assessment of astigmatism shows greater variability between instruments, sessions and observers.

To assess the validity and repeatability of the Aston Halometer. Setting:University clinic, UK. Design:Prospective repeated-measures experimental study Methods:The Aston Halometer comprises of a bright Light-Emitting-Diode (LED) glare source in the centre of an iPad4. Letters, subtending 0.21° (~0.3logMAR), were moved centrifugally from the LED in 0.05º steps in 8 orientation separated by 45° for each of 4 contrast levels (1000, 500, 100 and 25 Weber contrast units [Cw]) in random order. Bangerter 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 2m from the screen in a dark room with the iPad controlled from an iPhone via Bluetooth operated by the researcher. The Oculus C-Quant 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. Results:Halo size increased with the different Bangerter foils and target contrasts (F=29.564, p<0.001) as expected and in a similar pattern to straylight measures (F=80.655, p<0.001). Lower contrast letters showed better sensitivity, but larger glareobscured areas resulting in ceiling effects due to the screen's field-of-view, with 500Cwbeing the best compromise. Intra-observer and inter-observer repeatability of the AstonHalometer was good (500Cw: 0.84-0.93 and 0.53-0.73) and similar to the CQuant. Conclusions:The Aston Halometer provides a sensitive, repeatable way of quantifying a patient recognised form of disability glare in multiple orientations to add objectivity to subjectively reported discomfort glare.

Following implantation with Multifocal intraocular lenses (MIOLs) or monofocal intraocular lenses (IOLs), the study examines monocular and binocular visual function and patient reporting outcomes using a rigorous series of clinical assessments. Setting: BMI Southend Hospital, UK DESIGN: Prospective, randomised, double-masked clinical trial. METHODS: 100 subjects were randomised for bilateral implantation of either Bi-Flex 677MY MIOL or Bi-Flex 677AB IOL and were assessed at 3-6 months (V1) and 12-18 months (V2). Primary outcomes included distance, intermediate and near LogMAR visual acuities (VA) and defocus curve profile assessment. Secondary outcomes included reading speed, contrast sensitivity (CS) and the subjective perception of quality-of-vision. RESULTS: Uncorrected (MIOL 0.10±0.09LogMAR; IOL 0.09±0.11LogMAR) and best distancecorrected VA (MIOL 0.04±0.06LogMAR; IOL 0.01±0.07LogMAR) were comparable (p>0.05). Unaided near VA (UNVA p<0.001: MIOL 0.23±0.13LogMAR; IOL 0.55±0.20LogMAR) and distancecorrected near VA (DCNVA p<0.001: MIOL 0.24±0.13LogMAR; IOL 0.54±0.17LogMAR) were significantly improved with MIOLs. There was no significant difference in distance-corrected intermediate VA (DCIVA p=0.431: MIOL 0.38±0.13; IOL 0.39±0.13).Defocus curves demonstrated an increased range-of-focus amongst MIOLs (MIOL 4.14±1.10D; IOL 2.57±0.77D). Pelli-Robson CS was different at V1 (p<0.001) but similar by V2 (p=0.059).Overall satisfaction was high (>90%) in both groups for distance tasks whereas significantly different for near (MIOL 18.45±16.53LogUnits; MIOL 55.59±22.52LogUnits). CONCLUSIONS:Unaided near visual acuity is demonstrably better with MIOLs and there was greater subjective satisfaction with their quality-of-near-vision. Halos reported by the MIOL group was significant compared to the IOL group, but did not show an adverse effect on overall satisfaction.Multifocal intraocular lenses (MIOLs) are widely considered the most reliable method of achieving spectacle independence following cataract surgery. [1][2][3] MIOLs distribute the light between distant and near focal points whereby the vergence of the incident light dictates which focal point is conjugate to the retinal plane.The separation of these multiple focal points is determined by the addition power of the MIOL and to a lesser extent the biometry of the eye. High addition MIOLs (+4.00D or higher) are the zeitgeist of the designs used in the late 90s-early 2000s. Disadvantages of these early lenses included a close working distance and reduced intermediate vision. Moreover, the size of the dysphotopic phenomenon (commonly described as halo), associated with MIOLs, increases according to the addition power; these higher addition lenses generate larger haloes. 4,5 The light energy distribution between the retinal focal points created by a MIOL influences the overall quality of vision at different viewing distances. MIOLs that split light equally, create two focal points of comparative image quality. In contrast, distance dominant MIOLs allocate a higher per...

Purpose To evaluate visual performance with trifocal and extended depth of focus IOL at 1 year post-operatively. Setting BMI Southend Hospital. Design Cohort study. Methods An age-matched cohort of forty subjects bilaterally implanted with the AT LISA 839MP trifocal IOL (20 patients, 40 eyes) and the Tecnis Symfony extended depth of focus IOL (20 patients, 40 eyes) were assessed at 3–6 months and 12–18 months post-operatively. Primary outcome measures were distance (6 m), intermediate (70 cm), near visual acuity (40 cm), and analysis of defocus profiles. Secondary outcomes included contrast sensitivity, Radner reading performance, quality of vision and assessment of halos. Results Distance visual acuity (VA) and defocus areas were similar ( p = 0.07). No significant difference in intermediate VA was noted but the intermediate area of focus was greater in the EDoF (0.31 ± 0.12 LogMAR*m−1) compared to the trifocal (0.22 ± 0.08LogMAR*m−1) ( p = 0.02). However, all near metrics were significantly better in the trifocal group. 80% of trifocal subjects were spectacle independent compared to 50% EDoF subjects. Quality of vision questionnaire found no significant differences between groups, however halo scores were greater at 3–6 months in the trifocal group ( p < 0.01) but no differences were noted at 12–18 months. Conclusions Near vision is significantly better for the trifocal, thus greater levels of spectacle independence. The range of intermediate vision was greater for the EDoF but no difference in intermediate VA. In the early period, differences in contrast sensitivity and halo size/intensity were noted, however, by one-year these measures were not significantly different.

Introduction:To establish the most appropriate curve fitting method to allow accurate comparison of defocus curves derived from intraocular lenses (IOLs). Methods: Defocus curves were plotted in five IOL groups (monofocal, extended depth of focus, refractive bifocal, diffractive bifocal and trifocal). Polynomial curves from 2nd to 11th order and cubic splines were fitted. Goodness of fit (GOF) was assessed using five methods: least squares, coefficient of determination (R 2 adj ), Akaike information criteria (AIC), visual inspection and Snedecor and Cochran. Additional defocus steps at −2.25 D and −2.75 D were measured and compared to the calculated visual acuity (VA) values. Area under the defocus curve and range of focus were also compared.Results: Goodness of fit demonstrated variable results, with more lenient methods such as R 2 adj leading to overfitting and conservative methods such as AIC resulting in underfitting. Furthermore, conservative methods diminished the inflection points resulting in an underestimation of VA. Polynomial of at least 8th order was required for comparison of area methods, but overfitted the EDoF and monofocal groups; the spline curve was consistent for all IOLs and methods. Conclusions:This study demonstrates the inherent difficulty of selecting a single polynomial function. The R 2 method can be used cautiously along with visual inspection to guard against overfitting. Spline curves are suitable for all IOLs, guarding against the issues of overfitting. Therefore, for analysis of the defocus profile of IOLs, the fitting of a spline curves is advocated and should be used wherever possible.