Subjective Amplitude Of Accommodation Research Articles

Classification of accommodative insufficiency by monocular subjective push-up test is poorly predictive of monocular objective amplitudes in children and young adults.

To determine whether classification of accommodative insufficiency (AI) based on the subjective push-up test is indicative of reduced amplitude measured objectively. Monocular subjective accommodative amplitude was measured in participants 7-24 years of age with the push-up test; a 0.9 mm letter was moved towards the eye until first sustained blur occurred. Monocular objective amplitude was measured with the same target and an autorefractor for demands from 2.5 to 30 D. The maximum response was termed the amplitude. Near point of convergence (NPC) was measured in a subset of participants. Participants were classified into groups using subjective amplitude: normal amplitude or AI (amplitude < ((15 - 0.25 × age) - 2)). Objective amplitude was plotted by age for each group and one-way ANCOVA used to evaluate differences while controlling for age. For NPC measures, a t-test compared the magnitude of the break between those with and without AI. Fifty-five of 185 participants were classified as having AI. Objective amplitude decreased with age (0.20 D/year) and there was no significant difference in the age-adjusted mean amplitudes for the two groups (AI: 7.62 D, CI = 7.19, 8.04; Normal: 7.86 D, CI = 7.58, 8.15; p = 0.11). For the subset with NPC measures, participants classified as having AI had significantly more receded break values than those without AI (7.7 ± 5 vs. 3.7 ± 3 cm, p < 0.001). Factors other than accommodative ability may be contributing to lower subjective amplitude findings in individuals meeting the criterion for AI.

The Effect of Retinal Illuminance on the Subjective Amplitude of Accommodation.

We show that the amplitude of accommodation decreases with retinal illumination even under photopic reading conditions and a constant pupil size. This result provides a basis for clinical approaches that are not based on an optical explanation. We investigated the effect of retinal illuminance on the amplitude of accommodation while the pupil of the eye remained constant. The amplitudes of accommodation of 10 young subjects (from 20 to 38 years of age) and that of 10 presbyopic subjects (from 45 to 54 years of age) were measured subjectively through an artificial pupil of 5 mm using a Badal optometer and for four values of retinal illuminance: 222, 821, 2138, and 5074 trolands. Phenylephrine was instilled to all the subjects to ensure that their natural pupil was greater than the artificial one in all experimental runs. Linear mixed-effects model for repeated measures with age and log luminance as covariates were used to check whether changes in amplitude of accommodation with retinal illumination were statistically significant. In the range of illuminances tested, the amplitude of accommodation decreased on average from 6.34 to 4.35 D in the young subjects and from 1.69 to 1.04 D in the presbyopic subjects. Illuminance was associated with the amplitude of accommodation in both young and presbyopic groups, with P < .01. The reduction in the amplitude of accommodation with target illumination (a phenomenon named night presbyopia) under photopic light conditions is not only due to a reduction in the depth of focus as a consequence of pupil dilation; it is strongly affected by the decrease of retinal illumination.

Repeatability of two subjective accommodative amplitude measurements and agreement with an objective method

BackgroundThe aim was to compare the repeatability of subjective accommodative amplitude (AA) measurements obtained using the modified push‐up and minus‐lens methods and determine the agreement with objective AA by an autorefractor.MethodsThe right eyes of 47 adults aged 22–30-years (mean 25.1 ± 1.9) were measured by subjective AA using the modified push‐up and minus‐lens methods. Subjective AAs with first sustained blur and unreadable criteria were obtained with an average of three consecutive measurements. Measurements of the objective AA were simulated by the minus lens using an open‐field autorefractor. The repeatability of two subjective AA methods and the agreement among the different methods was assessed.ResultsThe AA value was dependent on the measuring method (F = 139.68, p < 0.001). The AA of the minus‐lens method with first sustained blur criterion (10.10 ± 1.71 D) was closest to the objective AA (9.01 ± 1.49 D). The minus‐lens method with unreadable criterion had the best repeatability. The agreement between the minus‐lens method and the objective methods was better than that between the modified push‐up and the objective methods based on the difference and 95 per cent limits of agreement. The agreement was highest between the minus‐lens method with the first sustained blur criterion and the objective method, which had the lowest average difference and a narrow 95 per cent limits of agreement.ConclusionsThe subjective minus‐lens method was more accurate for assessing the subjective AA in adults than the modified push‐up method. The minus‐lens method with the first sustained blur criterion was the optimal method for subjective AA. The minus‐lens method with unreadable criterion can also be applied to clinical measurements, although it was approximately 0.95 D larger than the minus‐lens method with the first sustained blur criterion.

Subjective and objective accommodation of the Crystalens Advanced Optics (AO) in patients 6 months after bilateral implantation

Background: The aim of this study was to analyze and compare objective and subjective accommodation in patients after bilateral implantation of the FDA-approved accommodating Crystalens Advanced Optics (AO). Material and methods: This study was performed on 8 eyes of 4 patients. The subjective accommodation was measured by monocular and binocular defocus curves under photopic and mesopic conditions. The objective accommodation was analyzed using partial coherence interferometry (PCI) and wavefront aberration. Pupil diameter at different set-ups and refraction were derived from wavefront data. Results: Uncorrected and corrected distance and uncorrected near visual acuity improved significantly following implantation of the Crystalens AO in all eyes. Only one patient needed spectacles to correct distance visual acuity. Mean distance uncorrected visual acuity was 0.05 ± 0.06 logMAR. All patients were able to read newspapers without spectacles. Mean near uncorrected visual acuity was 0.17 ± 0.12 logMAR. Subjective accommodative amplitude under photopic conditions was significantly better binocularly than monocularly (p = 0.03) and was significant worse monocularly under mesopic conditions than photopic conditions (p = 0.016). No significant changes in anterior chamber depth were observed by PCI, with a fixation on optical stimuli at different distances. There were also no significant changes in the wavefront aberrations between the different set-ups. Pupil diameter increased significantly in the near set-up under mesopic conditions. Conclusions: No objective change in lens configuration was observed under different set-ups. Due to a variety of factors involved in pseudoaccommodation (e.g. pupil diameter, astigmatism, and multifocality), the subjective accommodative amplitude tends to be overestimated relative to objective measurements. No real accommodative action was observed.

Comparison of the amplitude of accommodation determined subjectively and objectively in South African university students

Background: Historically, two clinical methods have been used for measuring the amplitude of accommodation, which are the push-up and minus lens methods. However, it has been documented that the push-up method overestimates amplitude of accommodation, while the minus lens method underestimates it.Aim: The purpose of this study was to compare subjective and objective procedures for determining the monocular amplitude of accommodation in young optometry students.Setting: The study was conducted in the optometry clinic at the university.Methods: Amplitude of accommodation was measured on 45 optometry students (17 males and 28 females, whose ages ranged from 21 to 27 years) using the push-up, push-down, minus lens, modified dynamic retinoscopy and Pascal dynamic retinoscopy methods. Data were collected by three different examiners in this study. One examiner measured all the subjective tests, while another examiner measured the modified dynamic retinoscopy. The third examiner measured the Pascal heterodynamic retinoscopy.Results: The highest amplitude of accommodation was obtained using the push-up method (10.23 ± 1.67 D), while the minus lens method gave the lowest subjective finding (8.43 ± 1.68 D). However, the subjective methods generally produced comparable results. Both retinoscopic methods showed the lowest mean amplitude of accommodation of approximately 6.50 ± 1.40 D. However, there was a high correlation between the various methods.Conclusion: The push-up and push-down methods overestimate the true amplitude of accommodation because of the relative magnification, while the minus lens method creates an abnormal viewing environment in which the target is stationary but the stimulus becomes increasingly minified. Subjective amplitude of accommodation is an inadequate measure to assess any true accommodation because it fails to differentiate between passive depth of focus and an active accommodative power change in the eye. Therefore, subjective measurement of the amplitude of accommodation may suggest that accommodation is present when it is not. Further research is needed to further validate dynamic retinoscopy as the optimal or best possible routine clinical method to assess the true amplitude of accommodation.

Loss of amplitude of accommodation in pre-presbyopic HIV and AIDS patients under treatment with antiretrovirals

Background: The prevalence of HIV and AIDS is causing an enormous public health burden. Its manifestations spare no organ. Ocular complications are mainly attributed to various opportunistic infections which are directly or indirectly caused by immune deficiency.Purpose and aim: The purpose of this study was to determine the effect of HIV and AIDS on subjective amplitude of accommodation of patients under treatment with antiretrovirals and then to compare their results to those of control subjects.Methods: The study took place over a period of 10 months. A quantitative study was carried out on 58 subjects (29 ± 5.5 years) with HIV and AIDS and 35 (28.67 ± 4.6 years) controls of similar age. Amplitude of accommodation was measured using the subjective Royal Air Force push-up method. The influence of CD4+ cell count was also recorded.Results: People with HIV and AIDS had lower mean amplitude of accommodation (5.69 ± 0.88 D) compared to controls (8.53 ± 1.2 D). The decrease in amplitude of accommodation did not show any correlation with the CD4+ cell count. Lower amplitude of accommodation exists in people living with HIV and AIDS when compared with age-related healthy people.Conclusion: The results suggest that patients with HIV and AIDS on antiretroviral drugs (ARVs) have reduced amplitude of accommodation and might experience presbyopia earlier in life than participants without HIV and AIDS. The reduced amplitude of accommodation could be the initial presentation of HIV infection before the systemic manifestation. The possible causes could be the direct neuronal infection by HIV-1, ARVs use, pathological changes of the lens and ciliary muscle or the sensory component of the visual system. It is unknown whether the reduced amplitude of accommodation occurred prior to antiretroviral therapy or represents an ongoing injury to the eye and visual system by the HIV.

Optical factors influencing the amplitude of accommodation

The purpose of this work was to find plausible predictors among optical parameters that may explain the inter-individual differences in subjective amplitude of accommodation not explained by age. An exploratory multivariable regression analysis was carried out retrospectively on a dataset with 180 eyes from 97 subjects (ages ranged from 20 to 58years). Subjective amplitudes of accommodation were recorded with the use of a custom-made Badal system. A commercial aberrometer was used to obtain each eye’s wavefront during the full range of accommodation. The plausible predictors under study were pupil diameter in the unaccommodated eye, its reduction with accommodation; fourth- and six-order Zernike spherical aberration, their reduction with accommodation, and subjective refraction. At a significance level of 0.05, only fourth- and sixth-order Zernike spherical aberration were found to be predictors of subjective amplitude of accommodation not explained by age, each explaining on their own less than 5% of the variance, and about 9% together. All other optical parameters explained less than 2%. Spherical aberration did not explain the greater variability for younger eyes than for older eyes. The remainder variability in amplitude of accommodation not explained by age or spherical aberration was about ±2.6D for 20year-old subjects, ±1.5D for 40year-old subjects, and about ±0.6D for 55year-old subjects. Optical factors do not seem to account for much of the inter-individual differences in subjective amplitude of accommodation. Most of the variability not explained by age must be due to anatomical differences and physiological, psychological, or other factors.

Functional Visual Acuity of Early Presbyopia

PurposeTo evaluate visual function in patients with early presbyopia using the functional visual acuity (FVA) test.MethodsThis study included 27 eyes of 27 healthy older volunteers (mean age, 44.1 ± 2.6 years) and 14 eyes of 14 healthy young volunteers (mean age, 28.4±4.8 years). The distance-corrected visual acuity (DCVA), distance-corrected near VA (DCNVA), subjective amplitude of accommodation (AA), and distance and near pupillary diameters were measured. The distance FVA and distance-corrected near FVA (DCNFVA) were measured using the FVA Measurement System. The standard Schirmer test and standard tear break-up time measurement also were performed.ResultsThe logarithm of the minimum angle of resolution (logMAR) DCVA was better than 0 in all subjects. The percentages of subjects with logMAR DCNVA below 0 was significantly lower in the presbyopia group than in the young group. The DCNFVA in the presbyopia group was significantly (P < 0.001) poorer than the DCNVA in that group. Significant linear negative correlations were seen between the DCNVA and AA (r = -0.507, P < 0.001) and the DCNFVA and AA (r = -0.681, P < 0.001) in the older subjects. Stepwise regression analysis showed that only the AA was a significant factor predictive of the DCNFVA in the presbyopia group. Tear function parameters were not adopted in the regression model.ConclusionsMeasurement of the DCNFVA can detect decreased AA in early presbyopia better than measurement of the conventional near VA. The DCNFVA is a good index for early presbyopia.

Evaluation of Objective Accommodation Power in Different Age Groups Using an Auto Accommodation Refractometer

Purpose: To evaluate the objective amplitude of accommodation in various age groups using an autorefractometer and to compare the results with subjective assessments on accommodation. Objective accommodative amplitude of artificial lenses in post-operative cataract patients was also measured. Methods: In this study, 41 patients who visited Korea University Guro Hospital from July through August 2014 were categorized into 6 different age groups. Accommodative amplitude was measured using long-distance refraction at 5 m and short-distance refraction at 20 cm. In 20 patients, subjective amplitude of accommodation was measured using the minus lens technique and was compared with the measured objective accommodative amplitude. Accommodative amplitude was also measured in 8 patients who received cataract surgery. Results: The mean accommodative ability in normal people was 2.38 D. The age groups of 10-19, 20-29, 30-39, 40-49, 50-59, and over 60 years showed accommodative amplitudes of 3.31 ± 0.99 D, 3.25 ± 0.34 D, 3.78 ± 0.68 D, 1.00 ± 0.60 D, 0.22 ± 0.23 D, 0.00 ± 0.00 D, respectively. The results showed a rapid decrease in accommodative ability of patients older than 40 years and demonstrated a correlation between objective and subjective amplitude of accommodation (Pearson’s correlation coefficient 0.838). There was a significant difference between objective and subjective accommodative amplitudes in artificial lenses (p = 0.015), with average objective and subjective measures of 0.10 ± 0.23 D and 0.59 ± 0.35 D, respectively. Conclusions: Measuring amplitude of accommodation using an autorefractometer can be useful in assessing results of presbyopia treatment. J Korean Ophthalmol Soc 2016;57(1):20-24

Fasting Plasma Sugar: A Predictor of Accommodative Function in Diabetes

Background: Diabetes has been associated with decline in accommodative function in some ethnic groups. This outcome, however, could differ since ethnic variations in accommodation have been noted. This study investigated the relationship between plasma sugar level on subjective accommodative amplitude and accommodative lag in black Africans with type-1 diabetes.Methods: An examiner-blind study of subjective accommodative amplitude and accommodative lag between 45 diabetic subjects (15 males, 30 females) aged 12–39 years and 45 age- and sex-matched healthy non-diabetic controls was conducted. Accommodative amplitude was measured by the push-up to blur/push-down to clear methods using a RAF rule, the accommodative lag by the MEM retinoscopy, and the fasting plasma sugar (FPS) by a glucose meter.Results: Comparatively, the diabetic subjects had significantly lower accommodative amplitude (10.1 ± 2.7 D versus 11.5 ± 2.4 D, respectively; p = 0.010) and greater accommodative lag (1.1 ± 0.4 D versus 0.7 ± 0.2 D; p < 0.001, respectively) than the controls. Multiple regression analyses showed that after adjusting for age, FPS concentration significantly predicted accommodative amplitude (R2 = 0.05, p = 0.022) and accommodative lag (R2 = 0.30, p < 0.001) in diabetes. Duration of diabetes was not significantly related to accommodative amplitude and accommodative lag.Conclusion: Diabetes mellitus in black Africans was associated with lower accommodative amplitude and greater accommodative lag. An adequate control of the plasma sugar concentration may be vital to maintain proper accommodative function.

The Effect of 3D Visual Simulator on Children’s Visual Acuity - A Pilot Study Comparing Two Different Modalities

Purpose :To evaluate the efficacy of two non-surgical interventions of vision improvement in children.Methods :A prospective, randomized, pilot study to compare fogging method and the use of head mounted 3D display. Subjects were children, between 5 to 15 years old, with normal best corrected visual acuity (BCVA) and up to -3D myopia. Subjects played a video game as near point work, and received one of the two methods of treatments. Measurements of uncorrected far visual acuity (UCVA), refraction with autorefractometer, and subjective accommodative amplitude were taken 3 times, at the baseline, after the near work, and after the treatment.Results :Both methods applied after near work, improved UCVA. Head mounted 3D display group showed significant improvement in UCVA and resulted in better UCVA than baseline. Fogging group showed improvement in subjective accommodative amplitude. While 3D display group did not show change in the refraction, fogging group’s myopic refraction showed significant increase indicating the eyes showed myopic change of eyes after near work and treatment.Discussion :Despite our lack of clear knowledge in the mechanisms, both methods improved UCVA after the treatments. The improvement in UCVA was not correlated to measured refraction values.Conclusion :UCVA after near work can be improved by repeating near and distant accommodation by fogging and 3D image viewing, although at the different degrees. Further investigation on mechanisms of improvements and their clinical significance are warranted.

Accommodative amplitude required for sustained near work

Many practitioners base the prescription of near vision additions on the assertion that only one half or two-thirds of an individual's amplitude of accommodation is sustainable for a prolonged period. To better understand how much eye focus needs to be restored for presbyopic corrections to be adequate, this study investigated the robustness of the pre-presbyopic human accommodative system during a sustained and intensive near vision task. Twenty-one pre-presbyopic volunteers (aged 26.1 ± 4.7 years) participated in the study. Binocular subjective amplitude of accommodation was measured before and after a prolonged reading exercise, using the RAF rule. During the 30 min reading task, the subject's closest comfortable eye-to-text distance and pupil size was monitored. Accommodative accuracy to 0.2, 1.0, 2.0, 3.0 and 4.0 D stimuli was determined objectively using a validated binocular open-view autorefractor immediately before, and after the reading task. Amplitude of accommodation (p=0.09) and accommodative accuracy (p>0.05) were statistically unchanged following the intensive near task. The mean proportion of accommodation exerted throughout the near exercise was 80.6% (range 45.3 ± 3.7 to 96.6 ± 4.3%), which increased as the task progressed (F=2.24, p=0.02). The mean percentage of accommodation utilised increased with subject age (r=0.517, p = 0.016). The pre-presbyopic human accommodative system is robust to fatigue during intense and prolonged near work. A greater proportion of one's amplitude of accommodation may be continuously exerted than previously suggested.

Pilot study of new focus-shift accommodating intraocular lens

To determine the visual and accommodative performance of the OPAL-A focus-shift accommodating intraocular lens (IOL). Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. In this study comprising unilateral phacoemulsification and accommodating IOL implantation, patients were followed for 6 months. Corrected distance (CDVA) and distance-corrected near (DCNVA) visual acuities were measured. Objective amplitude of accommodation was measured with an autorefractor and subjective amplitude of accommodation, using push-up tests and defocus curves. Physiological and pilocarpine-stimulated IOL movement was measured by anterior segment optical coherence tomography. The mean values at 1 month, 3 months, and 6 months, respectively, were as follows: CDVA, -0.06 +/- 0.08 (SD), -0.08 +/- 0.09, and -0.05 +/- 0.09; DCNVA, 0.31 +/- 0.15, 0.31 +/- 0.15, and 0.34 +/- 0.16; objective amplitude of accommodation, 0.36 +/- 0.38 diopters (D), 0.12 +/- 0.34 D, and 0.10 +/- 0.34 D; subjective amplitude of accommodation, 2.79 +/- 0.86 D, 2.55 +/- 0.85 D, and 2.50 +/- 0.62 D with push-up test and 0.90 +/- 0.40 D, 0.78 +/- 0.23 D, and 0.93 +/- 0.35 D with defocus curves. The maximum physiologic IOL shift at 1 month (mean 45.2 +/- 63.4 microm) occurred with a 3.0 D accommodative stimulus. At 6 months, the mean pilocarpine-stimulated forward IOL shift was 306 +/- 161 microm. Objective accommodation and forward axial shift were clinically insignificant with the accommodating IOL. The near visual performance was attributed to depth of focus rather than to true pseudophakic accommodation.

Clinical predictors of the optimal spectacle correction for comfort performing desktop tasks

Background: The best strategy for spectacle correction of presbyopia for near tasks has not been determined.Methods: Thirty volunteers over the age of 40 years were tested for subjective accommodative amplitude, pupillary size, fusional vergence, interpupillary distance, arm length, preferred working distance, near and far visual acuity and preferred reading correction in the phoropter and trial frames. Subjects performed near tasks (reading, writing and counting change) using various spectacle correction strengths. Predictors of the correction maximising near task comfort were determined by multivariable linear regression.Results: The mean age was 54.9 years (range 43 to 71) and 40 per cent had diabetes. Significant predictors of the most comfortable addition in univariate analyses were age (p < 0.001), interpupillary distance (p = 0.02), fusional vergence amplitude (p = 0.02), distance visual acuity in the worse eye (p = 0.01), vision at 40-cm in the worse eye with distance correction (p = 0.01), duration of diabetes (p = 0.01), and the preferred correction to read at 40-cm with the phoropter (p = 0.002) or trial frames (p < 0.001). Target distance selected wearing trial frames (in dioptres), arm length, and accommodative amplitude were not significant predictors (p > 0.15). The preferred addition wearing trial frames holding a reading target at a distance selected by the patient was the only independent predictor. Excluding this variable, distance visual acuity was predictive independent of age or near vision wearing distance correction. The distance selected for task performance was predicted by vision wearing distance correction at near and at distance.Conclusions: Multivariable linear regression can be used to generate tables based on distance visual acuity and age or near vision wearing distance correction to determine tentative near spectacle addition. Final spectacle correction for desktop tasks can be estimated by subjective refraction with trial frames.

Desktop Publishing and Validation of Custom Near Visual Acuity Charts

Customized visual acuity (VA) assessment is an important part of basic and clinical vision research. Desktop computer based distance VA measurements have been utilized, and shown to be accurate and reliable, but computer based near VA measurements have not been attempted, mainly due to the limited spatial resolution of computer monitors. In this paper, we demonstrate how to use desktop publishing to create printed custom near VA charts. We created a set of six near VA charts in a logarithmic progression, 20/20 through 20/63, with multiple lines of the same acuity level, different letter arrangements in each line and a random noise background. This design allowed repeated measures of subjective accommodative amplitude without the potential artifact of familiarity of the optotypes. The background maintained a constant and spatial frequency rich peripheral stimulus for accommodation across the six different acuity levels. The paper describes in detail how pixel-wise accurate black and white bitmaps of Sloan optotypes were used to create the printed custom VA charts. At all acuity levels, the physical sizes of the printed custom optotypes deviated no more than 0.034 log units from that of the standard, satisfying the 0.05 log unit ISO criterion we used to demonstrate physical equivalence. Also, at all acuity levels, log unit differences in the mean target distance for which reliable recognition of letters first occurred for the printed custom optotypes compared to the standard were found to be below 0.05, satisfying the 0.05 log unit ISO criterion we used to demonstrate functional equivalence. It is possible to use desktop publishing to create custom near VA charts that are physically and functionally equivalent to standard VA charts produced by a commercial printing process.

Optimizing measurement of subjective amplitude of accommodation with defocus curves

To determine whether letter sequences and/or lens-presentation order should be randomized when measuring defocus curves and to assess the most appropriate criterion for calculating the subjective amplitude of accommodation (AoA) from defocus curves. Eye Clinic, School of Life & Health Sciences, Aston University, Birmingham, United Kingdom. Defocus curves (from +3.00 diopters [D] to -3.00 D in 0.50 D steps) for 6 possible combinations of randomized or nonrandomized letter sequences and/or lens-presentation order were measured in a random order in 20 presbyopic subjects. Subjective AoA was calculated from the defocus curves by curve fitting using various published criteria, and each was correlated to subjective push-up AoA. Objective AoA was measured for comparison of blur tolerance and pupil size. Randomization of lens-presentation order and/or letter sequences, or lack of, did not affect the measured defocus curves (P >.05, analysis of variance). The range of defocus that maintains highest achievable visual acuity (allowing for variability of repeated measurement) was better correlated to (r = 0.84) and agreed best with (+/-0.50 D) subjective push-up AoA than any other relative or absolute acuity criterion used in previous studies. Nonrandomized letters and lens presentation on their own did not affect subjective AoA measured by defocus curves, although their combination should be avoided. Quantification of subjective AoA from defocus curves should be standardized to the range of defocus that maintains the best achievable visual acuity.

Is randomisation necessary for measuring defocus curves in pre-presbyopes?

Purpose Defocus curves are used to evaluate the subjective range of clear vision of presbyopic corrections such as in eyes implanted with accommodating intraocular lenses (IOLs). This study determines whether letter sequences and/or lens presentation order ought to be randomised when measuring defocus curves. Methods Defocus curves (range +2.00DS to −2.00DS) were measured on 18 pre-presbyopic subjects (mean age 24.1 ± 4.2 years) for six combinations of sequential or randomised positive or negative lens progression and non-randomised or randomised letter sequences. The letters were presented on a computerised logMAR chart at 6 m. Results Overall there was a statistically significant difference between the six combinations (ANOVA, p < 0.05) attributable to the combination of non-randomised letters with non-randomised lens progression from negative to positive defocus ( p < 0.01). There was no statistically significant difference in defocus curve measurements if both letters and lens order were randomised compared to if only one of these variables was randomised ( p > 0.05). Non-randomised letters, with a sequential lens progression from negative to positive, was significantly different to all other combinations when compared individually (Student's T-test, p < 0.003 on all comparisons), and was confirmed as the sole source of the overall significant difference. There was no statistically significant difference if both lens presentation order and letter sequences were randomised compared to if only one or the other of these variables was randomised. Conclusion Non-randomised letters and non-randomised lens progression on their own did not affect the subjective amplitude of accommodation as measured by defocus curves, although their combination should be avoided.

Longterm results of 1 CU® accommodative intraocular lens implantation: 2‐year follow‐up study

To evaluate the longterm efficacy of 1 CU accommodative intraocular lenses (IOLs) to restore near visual performance. This prospective study comprised 14 eyes previously included in a 6-month, case-control clinical trial, undergoing phacoemulsification and implantation of a 1 CU accommodative IOL. The main outcome measures were subjective refraction, uncorrected distance visual acuity (UCDVA), best corrected distance VA (BCDVA), distance-corrected near VA (DCNVA), best corrected near VA (BCNVA), and subjective amplitude of accommodation (AA). In addition, anterior and posterior capsule opacification were assessed. Patients were examined over a 2-year follow-up period. Distance and near visual performance worsened after 6 months. Uncorrected DVA and BCDVA were 0.8 +/- 2.1 and 1.0 +/- 0.8 at 6 months and 0.4 +/- 0.1 and 0.6 +/- 0.1 at 1 year, respectively (p = 0.001). Distance-corrected NVA and BCNVA were 3.7 +/- 2.1 Jaeger (J) and 1.0 +/- 0.7 J at 6 months and 8.1 +/- 0.7 J and 1.5 +/- 0.5 J at 1 year, respectively (p = 0.001). Anterior and posterior capsule opacification were present, respectively, in 28% and 21% of patients at 6 months and in 100% of patients at 1 and 2 years (p < 0.001). After Nd:YAG laser capsulotomy (performed in 100% of patients), UCDVA and BCDVA increased to 0.7 +/- 0.2 (p = 0.007) and 1.0 +/- 0.1 (p = 0.001), respectively, at 2 years. Distance-corrected NVA improved to 7.3 +/- 0.5 J (p = 0.006). Mean AA was 1.9 +/- 0.8 D at 6 months, 0.3 +/- 0.2 D (p = 0.004) at 1 year and 0.3 +/- 0.2 D at 2 years. Patients implanted with 1 CU IOLs lost their accommodation capacities with time because of the high incidence and degree of anterior and posterior capsule opacification. The accommodative lens material and design may have played a role in capsule fibrosis.

Objective Accommodative Amplitude and Dynamics with the 1CU Accommodative Intraocular Lens

To compare the objective accommodative amplitude and dynamics of eyes implanted with the one-compartment-unit (1CU; HumanOptics AG, Erlangen, Germany) accommodative intraocular lenses (IOLs) with that measured subjectively. Twenty eyes with a 1CU accommodative IOL implanted were refracted and distance and near acuity measured with a logMAR (logarithm of the minimum angle of resolution) chart. The objective accommodative stimulus-response curve for static targets between 0.17 and 4.00 D accommodative demand was measured with the SRW-5000 (Shin-Nippon Commerce Inc., Tokyo, Japan) and PowerRefractor (PlusOptiX, Nürnberg, Germany) autorefractors. Continuous objective recording of dynamic accommodation was measured with the SRW-5000, with the subject viewing a target moving from 0 to 2.50 D at 0.3 Hz through a Badal lens system. Wavefront aberrometry measures (Zywave; Bausch & Lomb, Rochester, NY) were made through undilated pupils. Subjective amplitude of accommodation was measured with the RAF (Royal Air Force accommodation and vergence measurement) rule. Four months after implantation best-corrected acuity was -0.01 +/- 0.16 logMAR at distance and 0.60 +/- 0.09 logMAR at near. Objectively, the static amplitude of accommodation was 0.72 +/- 0.38 D. The average dynamic amplitude of accommodation was 0.71 +/- 0.47 D, with a lag behind the target of 0.50 +/- 0.48 seconds. Aberrometry showed a decrease in power of the lens-eye combination from the center to the periphery in all subjects (on average, -0.38 +/- 0.28 D/mm). Subjective amplitude of accommodation was 2.24 +/- 0.42 D. Two years after 1CU implantation, refractive error and distance visual acuity remained relatively stable, but near visual acuity, and the subjective and objective amplitudes of accommodation decreased. The objective accommodating effects of the 1CU lens appear to be limited, although patients are able to track a moving target. Subjective and objective accommodation was reduced at the 2-year follow-up. The greater subjective amplitude of accommodation is likely to result from the eye's depth of focus of and the aspheric nature of the IOL.

Clinical study of the 1CU accommodating intraocular lens

Purpose To compare the near functional capacities of patients with an accommodating intraocular lens (IOL) with those of patients with a conventional monofocal IOL. Setting Department of Ophthalmology, University of Chieti, Chieti, Italy. Methods This prospective double-blind case-control study comprised 42 eyes that had phacoemulsification and implantation of 1 of 2 types of IOLs: HumanOptics accommodating 1CU® (study group) and Eurocrystal IFP 3G 6.00 (control group). The main outcome measures were subjective refraction, uncorrected distance acuity, best corrected distance acuity, distance corrected near acuity at 40 cm, best corrected near acuity at 40 cm, and subjective amplitude of accommodation. Patients were examined 7, 30, 90, and 180 days after surgery. Results Postoperatively, both groups had excellent uncorrected distance acuity, best corrected distance acuity, and best corrected near acuity. In the study group, the mean distance corrected near acuity (Jaeger) was 5.43 ± 0.98 (SD) (range 4 to 7) at 7 days, 2.33 ± 0.48 (range 2 to 3) at 1 and 3 months, and 3.66 ± 2.12 (range 2 to 7) at 6 months. In the control group, the mean distance corrected near acuity was 7.43 ± 0.50 (range 7 to 8) during the entire follow-up. The differences between the groups was statistically significant ( P<.001). The mean amplitude of accommodation was 0.00 diopter (D) in the control group and 1.14 ± 0.44 D (range 0.75 to 2.00 D) in the study group at 7 days, 2.36 ± 0.28 D (range 2.00 to 2.75 D) at 30 and 90 days, and 1.90 ± 0.77 D (range 0.75 to 2.75 D) at 6 months. Conclusions The 1CU accommodating IOL provided better useful spectacle-free near visual acuity than the conventional monofocal IOL. However, the accommodating mechanism can play a role in capsule fibrosis.