Myopia-correcting lenses decrease eye fatigue in a visual search task for both adolescents and adults.

The steady, world-wide increase in myopia prevalence in children over the past decades has raised concerns. As an early intervention for axial-length-related myopia, correcting lenses have been developed (such as Defocus Incorporated Multiple Segment (DIMS) lenses), which have been shown to be effective in slowing myopia progression. Beyond this direct effect, however, it is not known whether such lenses also affect other aspects important to the wearer, such as eye fatigue, and how such effects may differ across age, as these lenses so far are typically only tested with adolescents. In the present work, we therefore investigated perceived fatigue levels according to lens type (normal vs DIMS) and age (adolescents vs adults) in a demanding visual search task ("Finding Wally") at two difficulty levels (easy vs difficult). Whereas age and difficulty did not result in significant differences in eye fatigue, we found a clear reduction of fatigue levels in both age groups when wearing the correcting lenses. Hence, the additional accommodation of these lens types may result in less strain in a task requiring sustained eye movements at near viewing distances.

The Clouclip, a wearable device for measuring near-work and outdoor time: validation and comparison of objective measures with questionnaire estimates.

PURPOSE: To validate a novel wearable device that can measure both viewing distance and light exposure, Clouclip, and compare questionnaire estimates regarding near-work and outdoor time with the objective measures obtained using Clouclip. METHODS: Fifteen Clouclips were selected to measure different distances and levels of illuminance. With each Clouclip, five measurements at different distances and light intensities were measured and recorded. Eighty participants wore Clouclips for a week and completed an activity questionnaire afterwards. RESULTS: The intra- and inter-Clouclip coefficients were 1.00 and 0.99 for measuring distance and 1.00 and 1.00 for illuminance, respectively. Within the measurement limit, the maximum relative error was 2.07% for distance and 2.23% for illuminance. Assuming that <30 cm was the typical distance for near-work activities and >1000 Lux was the typical cut-off for outdoor environments, the questionnaire showed a trend of overestimation for both. The greatest overestimation of near-work occurred during the school period [Questionnaire: 4.73 hr (4.73, 5.07) versus Clouclip: 2.16 hr (1.74, 2.78); p < 0.01]. The greatest overestimation of outdoor activity also occurred during the school period [Questionnaire: 1.60 hr (1.33, 1.85) versus Clouclip: 1.21 hr (0.96, 1.50); p < 0.01]. Based on Clouclip, the total time spent outdoors was estimated to be 1.55 hr on school days, of which 0.34 hr occurred after school. For weekend days, however, the duration was only 0.17 hr. CONCLUSIONS: Clouclip had excellent precision and accuracy. Although the agreement between the questionnaire and Clouclip was relatively poor, they were able to complement each other to provide a more logical and feasible assessment of exposure to near-work and outdoor activity. Indoor-oriented lifestyles were found to predominate in Chinese children.

Effect of High Add Power, Medium Add Power, or Single-Vision Contact Lenses on Myopia Progression in Children: The BLINK Randomized Clinical Trial.

Importance: Slowing myopia progression could decrease the risk of sight-threatening complications. Objective: To determine whether soft multifocal contact lenses slow myopia progression in children, and whether high add power (+2.50 D) slows myopia progression more than medium (+1.50 D) add power lenses. Design, Setting, and Participants: A double-masked randomized clinical trial that took place at 2 optometry schools located in Columbus, Ohio, and Houston, Texas. A total of 294 consecutive eligible children aged 7 to 11 years with -0.75 D to -5.00 D of spherical component myopia and less than 1.00 D astigmatism were enrolled between September 22, 2014, and June 20, 2016. Follow-up was completed June 24, 2019. Interventions: Participants were randomly assigned to wear high add power (n = 98), medium add power (n = 98), or single-vision (n = 98) contact lenses. Main Outcomes and Measures: The primary outcome was the 3-year change in cycloplegic spherical equivalent autorefraction, as measured by the mean of 10 autorefraction readings. There were 11 secondary end points, 4 of which were analyzed for this study, including 3-year eye growth. Results: Among 294 randomized participants, 292 (99%) were included in the analyses (mean [SD] age, 10.3 [1.2] years; 177 [60.2%] were female; mean [SD] spherical equivalent refractive error, -2.39 [1.00] D). Adjusted 3-year myopia progression was -0.60 D for high add power, -0.89 D for medium add power, and -1.05 D for single-vision contact lenses. The difference in progression was 0.46 D (95% CI, 0.29-0.63) for high add power vs single vision, 0.30 D (95% CI, 0.13-0.47) for high add vs medium add power, and 0.16 D (95% CI, -0.01 to 0.33) for medium add power vs single vision. Of the 4 secondary end points, there were no statistically significant differences between the groups for 3 of the end points. Adjusted mean eye growth was 0.42 mm for high add power, 0.58 mm for medium add power, and 0.66 mm for single vision. The difference in eye growth was -0.23 mm (95% CI, -0.30 to -0.17) for high add power vs single vision, -0.16 mm (95% CI, -0.23 to -0.09) for high add vs medium add power, and -0.07 mm (95% CI, -0.14 to -0.01) for medium add power vs single vision. Conclusions and Relevance: Among children with myopia, treatment with high add power multifocal contact lenses significantly reduced the rate of myopia progression over 3 years compared with medium add power multifocal and single-vision contact lenses. However, further research is needed to understand the clinical importance of the observed differences. Trial Registration: ClinicalTrials.gov Identifier: NCT02255474.

Contrast sensitivity function with soft contact lens wear / Función de sensibilidad al contraste con el uso de lentes de contacto blandas

PURPOSES: To compare contrast sensitivity function (CSF) with soft contact lens (SCL) and spectacles wear. To investigate the effect of a three-month period of SCL wear on CSF. METHODS: Forty-seven myopic subjects with no history of contact lens (CL) wear were included in this longitudinal prospective study. CSF was measured with spectacles using the CSV-1000 (VectorVision, Greenvile, OH). Subsequently, subjects were fitted with a daily disposable lens (Nelfilcon-A, Stenofilcon-A or Nesofilcon-A) in one eye and a monthly disposable lens (Lotrafilcon-B, Comfilcon-A or Balafilcon-A) in the other eye and wore the same type of CLs for three months. CSF was measured again on the same day and after three months wearing CLs. Differences in CSF with spectacles and CLs on baseline and changes to CSF after three months of CLs wear were assessed. The effect of lens materials and wearing modality on CSF change was also investigated. RESULTS: CSF was higher with CLs in comparison to the values with spectacles for spatial frequencies of 3, 6 and 12 cycles per degree (cpd) (p < 0.05) while there was no difference for spatial frequency of 18 cpd (p = 0.114). No significant difference was found in the CSF with CLs between baseline and after three months of lens wear (p > 0.05). There was no difference in CSF between hydrogel and silicone CLs as well as when comparing daily with monthly wear CLs (p > 0.05). CONCLUSIÓN: CSF is better with CLs than with spectacles. CSF values with CL are similar between baseline and after 3 months of lens wear

OBJETIVOS: Comparar la función de sensibilidad al contraste (CSF) con el uso de lentillas blandas y gafas. Investigar el efecto en la CSF de un periodo de uso de lentillas blandas de tres meses. MÉTODOS: En este estudio longitudinal prospectivo incluimos a cuarenta y siete sujetos miopes sin antecedentes de uso de lentillas. La CSF se midió con gafas, utilizando el sistema CSV-1000 (VectorVision, Greenvile, OH). A continuación, se proporcionaron a los sujetos lentillas diarias desechables (Nelfilcon-A, Stenofilcon-A o Nesofilcon-A) en un ojo, y lentillas mensuales desechables (Lotrafilcon-B, Comfilcon-A or Balafilcon-A) en el otro ojo, utilizándose el mismo tipo de lentillas durante tres meses. Se volvió a medir la CSF el mismo día, y transcurridos tres meses de uso de lentillas. Se evaluaron las diferencias en cuanto a CSF con gafas y lentillas al inicio, y los cambios de CSF transcurridos tres meses de uso de lentillas. También se investigó el efecto en el cambio de CSF de las modalidades de las lentillas y la modalidad de uso. RESULTADOS: La CSF fue más alta con el uso de lentillas, en comparación con el uso de gafas para las frecuencias espaciales de 3, 6 y 12 ciclos por grado (cpg) (p < 0,05), mientras que no se produjo diferencia para la frecuencia espacial de 18 cpg (p = 0,114). No se encontró diferencia significativa de CSF entre el valor basal y transcurridos tres meses de uso de lentillas (p > 0,05). No se encontró diferencia de CSF entre las lentillas de hidrogel y silicona, ni al comparar el uso de lentillas diarias y mensuales (p > 0,05). CONCLUSIÓN: La CSF es mejor con lentillas que con gafas. Los valores de CSF con el uso de lentillas son similares entre el valor basal y transcurridos tres meses de uso de lentillas

Changing accommodation behaviour during multifocal soft contact lens wear using auditory biofeedback training.

Biofeedback training has been used to access autonomically-controlled body functions through visual or acoustic signals to manage conditions like anxiety and hyperactivity. Here we examined the use of auditory biofeedback to improve accommodative responses to near visual stimuli in patients wearing single vision (SV) and multifocal soft contact lenses (MFCL). MFCLs are one evidence-based treatment shown to be effective in slowing myopia progression in children. However, previous research found that the positive addition relaxed accommodation at near, possibly reducing the therapeutic benefit. Accommodation accuracy was examined in 18 emmetropes and 19 myopes while wearing SVCLs and MFCLs (centre-distance). Short periods of auditory biofeedback training to improve the response (reduce the lag of accommodation) was performed and accommodation re-assessed while patients wore the SVCLs and MFCLs. Significantly larger accommodative lags were measured with MFCLs compared to SV. Biofeedback training effectively reduced the lag by ≥0.3D in individuals of both groups with SVCL and MFCL wear. The training was more effective in myopes wearing their habitual SVCLs. This study shows that accommodation can be changed with short biofeedback training independent of the refractive state. With this proof-of-concept, we hypothesize that biofeedback training in myopic children wearing MFCLs might improve the treatment effectiveness.

Respuesta de los autores: Miopía, el reto de la oftalmología y su "explosiva epidemia" mundial / Author's reply: Myopia, the challenge of ophthalmology and its worldwide "explosive epidemic"

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Spectacles utilization and its impact on health-related quality of life among rural Chinese adolescents.

PURPOSE: The aims of the study were to assess the magnitude and predictors of the unmet need for spectacles utilization and to quantify its impact on health-related quality of life (HRQOL) among rural Chinese adolescents. METHODS: This school-based survey of 2346 grade-7 students (mean age: 13.8 years) was conducted in Southwestern China in 2016. Spectacles need was defined as uncorrected visual acuity (VA) of 20/40 or worse but correctable to 20/40 or better in the better-seeing eye, together with the presence of myopia of less than -0.5 diopters (D), hyperopia of more than +2.0 D, or astigmatism of more than 0.75 D in both eyes. The HRQOL was measured using self-reported versions of 23-item Pediatric Quality of Life Inventory Version 4.0 Generic Core Scales (PedsQL 4.0). RESULTS: Among 579 (24.7%) adolescents with an uncorrected VA of 20/40 or less, 483 (83.4%) needed vision corrections and 172 (35.6%) used them. Higher parental education levels (odds ratio (OR) = 2.73; 95% CI, 1.29-5.77), negative attitude regarding spectacles (OR = 0.49; 95% CI, 0.25-0.97), and poorer uncorrected VA (OR = 31.27; 95% CI, 3.76-260.23) were independent determinants for spectacles utilization. Adolescents not using spectacles had a lower HRQOL score compared to those using spectacles in terms of psychosocial health (65.91 vs. 70.59; P = 0.028), emotional health (56.85 vs. 63.24; P = 0.012), and social functioning (72.99 vs. 78.60; P = 0.036). CONCLUSIONS: The rate of spectacles utilization in rural China was low. Adolescents were not accustomed to use spectacles had a worse HRQOL score.

Clinical outcome and higher order aberrations after bilateral implantation of an extended depth of focus intraocular lens.

PURPOSE: The purpose of this study was to assess the clinical outcome after a bilateral implantation of an extended depth of focus intraocular lens in comparison to a monofocal intraocular lens. SETTING: Department of Ophthalmology, Charité-Medical University Berlin, Germany. PATIENTS AND METHODS: A total of 60 eyes of 30 patients were enrolled in this prospective, single-center study. The cataract patients underwent phacoemulsification with bilateral implantation of a TECNIS® Symfony (Abbott Medical Optics, Santa Ana, CA, USA, 15 patients) or a TECNIS Monofocal ZCB00 (Abbott Medical Optics, Santa Ana, CA, USA, 15 patients). Postoperative evaluations were performed after 1 and 3 months, including visual acuities at far, intermediate, and near distance. Mesopic, scotopic vision, and contrast sensitivity were investigated. Aberrometry was performed using an iTrace aberrometer with a pupil scan size of 5.0 mm. RESULTS: After 3 months, the TECNIS Symfony group reached an uncorrected visual acuity at far distance of -0.02 logMAR compared to -0.06 logMAR in the TECNIS Monofocal group ( p = 0.03). Regarding the uncorrected vision at intermediate and near distance the following values were obtained: intermediate visual acuity -0.13 versus 0.0 logMAR (TECNIS Symfony vs TECNIS Monofocal, p = 0.001) and near visual acuity 0.11 versus 0.26 logMAR (TECNIS Symfony vs TECNIS Monofocal, p = 0.001). Low-contrast visual acuities were 0.27 versus 0.20 logMar (TECNIS Symfony vs TECNIS Monofocal, p = 0.023). CONCLUSION: The TECNIS Symfony intraocular lens can be considered an appropriate alternative to multifocal intraocular lenses because of good visual results at far, intermediate, and near distance as well as in low-contrast vision.

Accuracy of Intraocular Lens Calculation Formulas.

PURPOSE: To compare the accuracy of intraocular lens (IOL) calculation formulas (Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Holladay 2, Olsen, and SRK/T) in the prediction of postoperative refraction using a single optical biometry device. DESIGN: Retrospective consecutive case series. PARTICIPANTS: A total of 13 301 cataract operations with an AcrySof SN60WF implant and 5200 operations with a SA60AT implant (Alcon Laboratories, Inc., Fort Worth, TX). METHODS: All patients undergoing cataract surgery between July 1, 2014, and December 31, 2015, with Lenstar 900 optical biometry were eligible. A single eye per patient was included in the final analysis, resulting in a total of 18 501 cases. We compared the performance of each formula with respect to the error in predicted spherical equivalent and evaluated the effect of applying the Wang-Koch (WK) adjustment for eyes with axial length >25.0 mm on 4 of the formulas. RESULTS: For the SN60WF, the standard deviation of the prediction error, in order of lowest to highest, was the Barrett Universal II (0.404), Olsen (0.424), Haigis (0.437), Holladay 2 (0.450), Holladay 1 (0.453), SRK/T (0.463), and Hoffer Q (0.473), and the results for the SA60AT were similar. The Barrett formula was significantly better than the other formulas in postoperative refraction prediction (P < 0.01) for both IOL types. Application of the WK axial length modification generally resulted in a shift from hyperopic to myopic outcomes in long eyes. CONCLUSIONS: Overall, the Barrett Universal II formula had the lowest prediction error for the 2 IOL models studied.

Short-Term Adaptation of Accommodative Responses in Myopes Fitted With Multifocal Contact Lenses.

OBJECTIVES: To investigate whether adaptation of accommodative responses occurred in non-presbyopic myopes fitted with four multifocal contact lens (MFCL) designs. METHODS: Prospective, subject-masked clinical investigation comprising 40 experienced myopic lens wearers (18-25 years) fitted bilaterally with single-vision (SV) control lens (Air Optix Aqua [Alcon, Fort Worth, TX]) and randomized to two of four test MFCL (Proclear MFCL [Distance and Near] [CooperVision, Pleasanton, CA], Air Optix Aqua MFCL, Purevision MFCL [Bausch & Lomb, Rochester, NY]). Lenses were dispensed on a daily wear basis and worn for a minimum of 8 (maximum 14) days over three assessment visits, with a 1-week wash out between stages. Paraxial curvature matched spherical equivalent (M) was measured with lenses on eye using the BHVI-EyeMapper with an internal movable fixation target positioned at target vergences of +1.00 diopter (D) (fogging) and -2.00 to -5.00 in 1.00 D steps (accommodative stimuli). Accommodative facility was assessed by several flips of ±2.00 D/min (cycles/min) at 33 cm and horizontal phoria with a Howell phoria card at distance (3 m) and near (33 cm). RESULTS: For center-distance MFCL (Proclear D), the spherical equivalent (M) at all near vergences became significantly more negative at the follow-up visits compared with the dispensing visit (P<0.029). For all center-near MFCLs and SV lens, M remained invariant during the adaptation period, however (P≥0.267). At distance, M became significantly less minus with Air Optix Aqua MFCL over time (P=0.049). Accommodative facility increased over the three assessment visits for participants wearing Air Optix Aqua SV, Air Optix Aqua MFCL, and PureVision MFCL (P=0.003). Distance and near horizontal phoria remained stable over the three assessment visits for all lens types (P≥0.181). CONCLUSIONS: Adaptation differences were not consistently found for static accommodative measures gauged by M, as measured with lenses on eye, and phoria but were found in dynamic measures (facility), perhaps indicating some learning effects. Accommodative adaptation seems unlikely to occur with long-term MFCL in non-presbyopes.

Types of Lamp for Homework and Myopia among Chinese School-Aged Children.

PURPOSE: We aim to determine the association of the types of lamp for homework including incandescent lamp, fluorescent lamp, and light-emitting diode (LED) lamp with the prevalence of myopia in Chinese children. METHODS: 2346 grade 7 students from ten middle schools (93.5% response rate) aged 13 to 14 years in Mojiang, a small county located in Southwestern China, participated in the study. Refractive error was measured with cycloplegia using an autorefractor by optometrists or trained technicians. An IOL Master was used to measure ocular biometric parameters including axial length (AL). Information regarding the types of lamp for homework af``ter schools was collected by questionnaires. RESULTS: Of all the study participants, 693 (29.5%) were affected by myopia, with the prevalence estimates being higher in girls (36.8%; 95% confidence interval [CI]: 34.0, 39.6) than in boys (22.8%; 95% CI: 20.4, 25.1) (P < 0.001). After adjusting for potential confounders such as gender, height, parental history of myopia, time on computer use, time on watching TV, time outdoors, and time on reading and writing, participants using LED lamps for homework had a more myopic refractive error and a longer AL compared with those using incandescent or fluorescent lamps. There were no significant differences in myopia prevalence between children using incandescent and fluorescent lamps for homework. The population attributable risk percentage for myopia associated with using LED lamps for homework after schools was 11.2%. CONCLUSIONS: Using LED lamps for homework after schools might contribute to the development of myopia among school-aged children.

[Clinical observation on monovision of cataract surgery with different near addition].

Objective: To observe the influence on spectacle independence, satisfaction and visual function after cataract surgery monovision with different ADD. Methods: Prospective clinical study. All patients were collected from the department of ophthalmology, Shanghai JiaoTong University Affiliated Sixth People's Hospital who were diagnosed as bilateral cataract from Oct. 2013 to Mar. 2015. This study comprised 64 cases (128 eyes). All consecutive patients scheduled to undergo bilateral cataract phacoemulsification and implantation of a monofocal AcrySof IQ IOL. The average age of patients was (65.4± 6.0) years old, ranged from 51 to 70 years. 28 males and 36 females. According to the different demands of spectacle independence and living habits of patients, all cases were divided into two groups: MV1 group (32 patients), whose near addition being 1.25-1.75 D and MV2 group (32 patients), whose near addition being 2.25-2.75 D. Parameters 6 months postoperatively included binocular uncorrected distance, intermediate, and near visual acuities, stereo vision and refractive states were analyzed. Parameters of spectacle independence, subjective visual symptoms and patient satisfaction according to visual function questionnaire were analyzed at the same time. T test was used to compare uncorrected visual acuity. Whitney U test was operated in stereo vision comparison. Chi-square test was applied in sex-distribution comparison and visual function questionnaire between two groups. Results: The uncorrected distance vision in MV1 group was (0.09±0.09), while it was (0.11±0.08) in MV2 group. The uncorrected intermediate vision in MV1 group was (0.27±0.25), and it was (0.30±0.22) in MV2 group. There were no significant difference between two groups in bilateral uncorrected distance vision (t=1.62, P=0.264, LogMAR), intermediate (t=- 0.23, P=0.876, LogMAR). However, there was significant difference between two groups in uncorrected near vision (t=2.38, P=0.021, LogMAR). It was (0.06±0.06) in MV1 group and (0.02±0.07) in MV2 group. Moreover, near stereo vision was better in MV1 group than MV2 group (Z=- 1.29, P=0.031). On the questionnaire, all patients in two groups had no significant difference in their daily lives discomfort (χ(2)=0.10, P=0.756). In MV2 group, there were 2 patients complained obstacles while walking stairs dimly. In MV1 group, there were 3 patients had to wear low degrees of presbyopic glasses when they were on near work. Percentage of patients spectacle independence was less than 90% in MV1 groups. In MV2 group, one case needed low degrees of myopic glasses when he was on intermediate computer work and playing table games. Conclusion: Different near addition has similar advantages to different patients on spectacle independence, satisfaction and visual function after cataract surgery. (Chin J Ophthalmol,2017,53: 451-454).

Rapid Vision Correction by Special Operations Forces.

BACKGROUND: This report describes a rapid method of vision correction used by Special Operations Medics in multiple operational engagements. METHODS: Between 2011 and 2015, Special Operations Medics used an algorithm- driven refraction technique. A standard block of instruction was provided to the medics, along with a packaged kit. The technique was used in multiple operational engagements with host nation military and civilians. Data collected for program evaluation were later analyzed to assess the utility of the technique. RESULTS: Glasses were distributed to 230 patients with complaints of either decreased distance or near (reading). Most patients (84%) with distance complaints achieved corrected binocular vision of 20/40 or better, and 97% of patients with near-vision complaints achieved corrected near-binocular vision of 20/40 or better. There was no statistically significant difference between the percentages of patients achieving 20/40 when medics used the technique under direct supervision versus independent use. CONCLUSION: A basic refraction technique using a designed kit allows for meaningful improvement in distance and/or near vision at austere locations. Special Operations Medics can leverage this approach after specific training with minimal time commitment. It can serve as a rapid, effective intervention with multiple applications in diverse operational environments.

[Intraocular lens power calculation for high myopic eyes with cataract: comparison of three formulas].

Objective: To compare the accuracy of three different formulas for intraocular lens power calculation in high myopic eyes with cataract and analyze their influencial factors. Methods: One hundred and three high myopic patients of cataract (103 eyes), with average age of 60.2±8.8 years old (39.0-77.0), including 45 male and 54 female and with axial length ≥ 26 mm were enrolled in this retrospective case-series study. All of them underwent routine ocular examination and IOLMastermeasurement preoperatively and then underwent phacoemulsification through temporal clear-corneal incision with implantation of HumanOptic posterior chamber Intraocular lens (IOL). All analyses were conducted using SPSS version 19.0. Repeated-measures analysis of variance was applied to compare the refractive results one month postoperatively with the predicted IOL powers calculated by SRK/T, Holladay 1, or Haigis formula before surgery. The differences were further compared based on different grouping of axial length (AXL), corneal curvature (K) and corneal astigmatism (CA). The accuracies of the three formulas were analyzed using Bland-Altman analyses and the possible error sources of each formula were analyzed using multiple regression model. Results: The majority of patients enrolled had hyperopic shift after cataract surgery. The mean errors (ME) of the three formulas were SRK/T: 0.70±0.89D, Holladay 1: (1.20±0.88) D and Haigis: (0.60±0.88) D; the mean absolute errors (MAE) of the three formulas were (0.81±0.79) D, (1.23±0.84) D and (0.76±0.74) D, respectively. Both ME and MAE of Holladay formula were significantly greater than the other two formulas (F=86.31, P<0.01). Besides, the proportion of patients having a prediction error within 0.50 D was lower in those using Holladay formula (20.4%, 21/103) than the other two (SRK/T: 38.8%, 40/103, χ(2)=8.41, P<0.01, Haigis: 45.6%, 47/103, χ(2)=14.84, P<0.01). Bland-Altman analyses showed that the accuracies of all the three formulas were acceptable in patients of cataract with high myopia in clinical practice. ME and MAE tended to be larger with longer axial length, larger corneal curvature and astigmatism of the patients in all three formulas. However, in eyes with axial length> 30 mm or corneal curvature ≤43.00 D, the MAE of Haigis formula was lower than that of SRK/T formula (F=63.26,63.94, both P<0.01). The prediction error of SRK/T formula was positively correlated with axial length and corneal astigmatism (F=33.97, r=0.66, ß=0.48, P<0.01 and ß=0.42, P<0.01), while for Holladay and Haigis formulas, in addition to the previous two factors, the errors were also positively correlated with mean corneal curvature (Holladay 1: F=31.26, r=0.72, AXL: ß=0.52, P<0.01, K: ß=0.20, P<0.05 and CA: ß=0.37, P<0.01; Haigis: F=30.96, r=0.72, AXL: ß=0.33, P<0.01, K: ß=0.40, P<0.01 and CA: ß=0.37, P<0.01). Conclusions: In the selection of IOL formula for high myopic patients with cataract, Haigis or SRK/T would reduce the prediction error and serve as the more accurate formulas than Holladay 1. Haigis formula may be more accurate than SRK/T formula in case of AXL>30 mm or K≤43.00 D. (Chin J Ophthalmol, 2017, 53: 260-265).

Portable electronic vision enhancement systems in comparison with optical magnifiers for near vision activities: an economic evaluation alongside a randomized crossover trial.

PURPOSE: To determine the incremental cost-effectiveness of portable electronic vision enhancement system (p-EVES) devices compared with optical low vision aids (LVAs), for improving near vision visual function, quality of life and well-being of people with a visual impairment. METHODS: An AB/BA randomized crossover trial design was used. Eighty-two participants completed the study. Participants were current users of optical LVAs who had not tried a p-EVES device before and had a stable visual impairment. The trial intervention was the addition of a p-EVES device to the participant's existing optical LVA(s) for 2 months, and the control intervention was optical LVA use only, for 2 months. Cost-effectiveness and cost-utility analyses were conducted from a societal perspective. RESULTS: The mean cost of the p-EVES intervention was £448. Carer costs were £30 (4.46 hr) less for the p-EVES intervention compared with the LVA only control. The mean difference in total costs was £417. Bootstrapping gave an incremental cost-effectiveness ratio (ICER) of £736 (95% CI £481 to £1525) for a 7% improvement in near vision visual function. Cost per quality-adjusted life year (QALY) ranged from £56 991 (lower 95% CI = £19 801) to £66 490 (lower 95% CI = £23 055). Sensitivity analysis varying the commercial price of the p-EVES device reduced ICERs by up to 75%, with cost per QALYs falling below £30 000. CONCLUSION: Portable electronic vision enhancement system (p-EVES) devices are likely to be a cost-effective use of healthcare resources for improving near vision visual function, but this does not translate into cost-effective improvements in quality of life, capability or well-being.

Binocular function changes produced in response to overnight orthokeratology.

PURPOSE: To analyze the binocular function changes produced on subjects undergoing overnight orthokeratology (OK) treatment over short-term (3 months) and long-term (3 years) wear. METHODS: A prospective, longitudinal study on young adult subjects with low to moderate myopia was carried out. Binocular function was assessed by the following sequence of tests: Distance and near horizontal phoria (Von Graefe technique), distance and near horizontal vergence ranges (Risley rotary prisms), accommodative convergence/accommodation (AC/A) ratio (gradient method) and the near point of convergence (standard push-up technique). The short-term sample consisted of: 21 subjects in the control group, 26 in a corneal refractive therapy (CRT) treatment lenses group and 25 in a Seefree treatment lenses group. Those subjects were evaluated at baseline and at a 3-month follow-up visit. Twenty one subjects were old CRT wearers that attended a 3-year follow-up visit (long-term group). RESULTS: A statistically significant difference over the 3-month treatment was found for divergence at distance: the break point decreased 1.4 Δ (p = 0.0006) in the CRT group and the recovery point increased 1.2 Δ (p = 0.001) in the Seefree group. Also, the Seefree group had an exophoric trend of 2.3 Δ at near (p = 0.02) and a base-out break decrease of 2.3 Δ (p = 0.03). For the long-term group, only the base-out break point at distant vision showed a statistically significant difference of 4.9 Δ (p = 0.02). CONCLUSIONS: OK induces minimal changes in the binocular function for either short-term or long-term periods, apart from a near exophoric trend over the short-term period.