Brightness Acuity Tester Research Articles

Glaucoma and glare.

To determine whether a purpose-built glare tester, in combination with new glare-specific questions, can better assess glaucoma patients' experience of glare and visual disability than visual acuity (VA) or visual fields alone. Consecutive patients attending for visual fields in a single glaucoma clinic from 03/06/2019-01/11/2019 underwent VA assessment using a Brightness Acuity Tester as a glare source, examination for media opacities, and completed the VFQ-25 with four additional glare-related questions. One hundred and sixteen eyes (64 patients) were included for analysis. The amount of disability glare (VA reduction due to glare) was compared according to presence/absence of media opacity and glaucoma severity. Subjective glare symptoms were compared with objective disability glare measurement using a Bland-Altman plot. Patients with advanced-severe glaucoma had significantly worse disability glare than those with mild-moderate glaucoma. VA reduction due to glare from mild-moderate to acute-severe glaucoma (mean -3.4 letters, P = 0.01, CI -0.8, -6.0) was of almost identical magnitude to that due to presence of any media opacity (mean -3.3 letters, P = 0.03, CI -0.4, -6.2). There was a trend towards greater disability glare in more symptomatic patients, with good agreement between subjective and objective glare measurements for those with few glare signs or symptoms, but progressively more variation either side of agreement as either measurement worsened. Glaucoma is associated with objective and subjective acuity reduction in the presence of glare. We demonstrated an increase in disability glare in patients with more severe glaucoma. The worse the glare symptoms or signs, the more variable the agreement between objective and subjective assessments.

Induced glare testing — an underutilized test in evaluating visual disability in patients presenting with symptomatic cataracts

Background: Cataract increases intraocular light scatter which affects the retinal image contrast and sensitivity. Symptomatic patients with cataract complain of a drop in the quality of vision or glare affecting daily routine even with preserved visual acuity. This study was aimed to quantify the drop in the glare induced visual acuity (VA) and contrast sensitivity (CS) in different morphological types of cataracts. Material and methods: This was an observational study on a prospective cohort, conducted at a tertiary-care centre in South-India. Patients admitted for cataract surgeries between March and September 2017 with BCVA ≥ 6/60 (Snellen) and ≥ 40 years were enrolled. LogMAR VA and CS were measured pre and post-operatively, with and without glare induction using brightness acuity tester. Patients were sub-categorised based on morphology and the presence of glare as a symptom. Paired-t test for the pre- and post-operative values and analysis with Bonferroni’s adjustment were the statistical methods used. Results: Data of 78 patients were sub-categorised and analysed. Glare induction with high glare was significant in all the studied groups. LogMAR VA was affected most in group 3 (0.20, 10 letters, p < 0.05) and the CS in group 2 (0.62, 4.1 step drop, p < 0.05). Patients who had glare as a symptom had an average greater drop in LogMAR VA (0.30, p = 0.01) and CS (–0.29, p = 0.03) when induced with a high glare. Conclusions: All morphological types of cataracts affect VA and CS to a greater extent in conditions of bright lighting. Glare induced VA and CS testing is a sensitive and an adjunct tool to traditional high contrast VA testing, in evaluating the visual dysfunction of patients presenting with symptomatic cataracts.

Optical functional performance of the osteo-odonto-keratoprosthesis.

The aim of this study was to evaluate optical and visual functional performance of the osteo-odonto-keratoprosthesis (OOKP). Optical design and analysis was performed with customized optical design software. Nine patients with implanted OOKP devices and 9 age-matched control patients were assessed. Contrast sensitivity was assessed and glare effect was measured with a brightness acuity test. All OOKP patients underwent kinetic Goldmann perimetry and wavefront aberrometry and completed the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25). Optical analysis showed that the optical cylinder is near diffraction-limited. A reduction in median visual acuity (VA) with increasing glare settings was observed from 0.04 logMAR (without glare) to 0.20 logMAR (with glare at "high" setting) and significantly reduced statistically when compared with the control group at all levels of glare (P < 0.05). Contrast sensitivity was significantly reduced when compared with age-matched controls at medium and high spatial frequencies (P < 0.05). Median Goldmann perimetry was 65 degrees (interquartile range, 64-74 degrees; V-4e isopters) and 69 degrees excluding 2 glaucomatous subjects. Several vision-related NEI VFQ-25 subscales correlated significantly with VA at various brightness acuity test levels and contrast sensitivity at medium spatial frequencies, including dependency, general vision, near activities and distance activities. The OOKP optical cylinder provides patients with a good level of VA that is significantly reduced by glare. We have shown in vivo that updates to the optical cylinder design have improved the patient's field of view. Reduction of glare and refinement of cylinder alignment methods may further improve visual function and patient satisfaction.

A study of the real life performance of OOKP optical cylinders

AbstractPurpose To evaluate the optical and visual functional characteristics of the Osteo‐Odonto‐Keratoprosthesis (OOKP)Methods Nine patients with implanted OOKP devices were examined. Glare effect (Low, Medium and High intensity) was measured with a brightness acuity test (BAT) and contrast sensitivity was assessed using Metropsis Visual Stimulus Generation software (Cambridge Research System) at 0.3; 0.7; 2.20; 3.50; 10.4 and 14.5 cpd. Kinetic Goldmann perimetry and wavefront aberrometry (Nidek OPD‐scan) were performed in each patient. All patients completed a Quality‐of‐Life questionnaire (NEI VFQ‐25)Results A reduction in mean visual acuity (logMAR) with increasing glare settings was observed from 0.12 without BAT to 0.27 with BAT at High. Mean visual acuities (logMAR) measured with BAT at Medium (Mann Whitney U‐test p&lt;0.05) and High (U‐Test p&lt;0.01) intensity settings were found to be significantly reduced statistically when compared to VA without BAT. Contrast Sensitivity was significantly reduced when compared to age‐matched control at medium and high spatial frequencies. Several vision‐related VFQ‐25 sub‐scales correlated significantly with visual acuity at various BAT levels such as General Vision, Near Activities and Distance Activities (correlation coefficients: ‐0.71 to ‐0.86; 0.05&gt;p&gt;0.001). Correlation with these subscales was also observed with contrast sensitivity at medium spatial frequencies (‐0.67 to ‐0.83; 0.05&gt;p&gt;0.001)Conclusion The optics of the OOKP can provide patients with excellent visual acuity that correlates well with visual function. Visual acuity is significantly reduced by glare and patients experienced a lower contrast sensitivity compared to age‐matched controls. Glare reduction and cylinder alignment could further improve function

Forward light scatter and contrast sensitivity in keratoconic patients

The aim of this study was to obtain intraocular forward light scatter (FLS) data in keratoconus patients and to explore possible relationships with contrast sensitivity. Intraocular straylight was assessed in the right eye of 10 visually-normal subjects (31±5 years) and 5 keratoconus patients (34±9 years) using the van den Berg straylight meter. Contrast sensitivity was also measured in both groups, with and without a glare source provided by the Brightness Acuity Tester (BAT), using a Pelli-Robson chart. Inclusion criteria for the keratoconic patients were chosen to avoid natural causes of increased scatter and to limit the influence of factors that could affect the straylight measurements. Intraocular light scatter was significantly greater in the keratoconic patients than in normal subjects for each of the three eccentricities tested (Mann-Whitney U test (2-tailed): Z≤-2.2, p≤0.027). Baseline Pelli-Robson contrast sensitivity was also found to be lower in the keratoconus group than in the normal subjects (Mann-Whitney U test: Z=-2.2, p=0.023). Under glare conditions contrast loss was significantly greater in the keratoconic patients than in the normal subjects (Mann-Whitney U test: Z=-2.5, p=0.013). High levels of negative correlation were found between the magnitudes of intraocular straylight and baseline contrast sensitivity in the keratoconus group (Spearman's correlation coefficient (RS)≤-0.87, p≤0.027). The high values of straylight measured in the keratoconic patients cannot be explained by age or scarring and could be related to the structural degradation of the cornea. Further investigation of intraocular scatter in keratoconus is warranted to improve our current understanding of the visual deficits associated with this pathology.

The effect of pupil dilation on driving vision in Canada.

To determine whether there is a clinically significant reduction in visual acuity (VA) or contrast sensitivity (CS), with and without glare, following examination with pupil dilation in patients currently driving. From November 1, 2004, to February 28, 2005, 105 consecutive patients were assessed in our institution. The better eye was assessed pre- and post-dilation with and without glare administered through the Brightness Acuity Tester. VA was assessed using the Early Treatment in Diabetic Retinopathy Study (ETDRS) and Snellen charts. CS was measured using the Vistech VCTS 6500 Chart. With no glare, there was a mean reduction of 4.8 letters read from the ETDRS chart following dilation (p < 0.001). With glare, there was a mean reduction of 7.1 letters (p < 0.001). Compared with patients with initial VA of 20/20, patients presenting with a Snellen VA of 20/25 to 20/40 had a 9.75 relative risk of postdilation VA worse than 20/40, whereas patients with initial VA of 20/40 had a 19.8 relative risk of postdilation VA worse than 20/40. With the addition of glare, these relative risks increased to 13.9 and 28.8, respectively. Without glare, there was a significant reduction in CS after dilation at spatial frequencies of 2.0, 4.0, and 6.0 cycles/degree (p = 0.014, p < 0.001, and p < 0.001, respectively). With glare, there was a greater reduction in CS at these 3 spatial frequencies (p < 0.001 for all). There is a significant reduction in VA and CS after dilation that is further confounded by the effect of glare. This reduction may limit some patients from driving after dilation.

Optical Functional Properties of the Boston Keratoprosthesis

To evaluate the optical characteristics of the Boston Keratoprosthesis (KPro), identify glare sources, evaluate possible glare control, and examine the benefit of implantation when the fellow eye has normal vision. Computed and optical-bench-measured point spread function (PSF) and glare sources were compared. A translucent plastic cornea was used to determine the impact of glare caused by scatter in the cornea and its control with a dark-iris tinted contact lens. The effect of glare in implanted eyes was measured with a brightness acuity test (BAT), with and without the dark-iris contact lens. Computed and measured visual fields were compared. Stereopsis was measured in patients with an intact fellow eye. Computed and measured modulation transfer functions for the KPro were found to be very close to the diffraction limit. Both the model-eye measurements and patients' BAT glare responses identified that the hazy corneal graft surrounding the KPro is the main source of glare and can be controlled with a dark-iris contact lens. The lid effectively blocks the light that would be scattered in the hazy cornea of patients in whom the type II KPro was implanted. An intact fellow eye remains the dominant eye, with better acuity, and the KPro eye supports only minimal stereo ability and does not expand the binocular visual field. Glare can be reduced significantly with the use of a contact lens with a dark iris. Implanting the KPro in a patient whose fellow eye has normal or near normal vision does not seem to improve visual function.

Optical qualities of the Boston keratoprosthesis

Abstract Purpose To evaluate the optical characteristics of the Boston Keratoprosthesis (KPro) in relation to visual function. To determine glare sources and evaluate possible glare control. To explore the feasibility of fundus imaging. To examine the binocular consequences of implanting the device when the fellow eye has normal vision. Methods The computed and optical bench measured point spread function and corresponding modulation transfer function (MTF), as well as glare sources, were compared. A model eye construct was used to determine the relative impact of different sources of glare and its control. The effect of glare in eyes implanted with a KPro was measured with a Brightness Acuity Test (BAT) with and without a dark iris contact lens (dCL) for 8 eyes with Type I and 2 eyes with Type II KPro. Computed and measured visual fields were compared. The power of a lens that provides a wide field view of the fundus was calculated. Images with a fundus camera and lenses were obtained. Stereopsis was measured in 5 Type I KPro patients with an intact fellow eye. Results The computed and measured MTF for the KPro were found to be very close to the diffraction limit. Both the model eye and patients testing identified the hazy corneal graft as the main source of glare, which was controlled with a dCL. In 3 patients with an intact fellow eye, modest stereo acuity was gained with KPro implantation. Binocular visual field is not expanded when implanting a patient with normal fellow eye. Good image quality of the fundus is achieved in eyes with clear media. Conclusion Disability glare can be reduced with the use of a dCL. Implanting the KPro in a patient with an intact fellow eye only marginally improves visual function. Adequate fundus imaging can be obtained.

Glare Testing in Patients with Cataract after Dilation

To learn whether dilating the pupil will have an impact on glare testing for cataract evaluation. Evaluation of diagnostic test. Fifty-four adult patients at the Jones Eye Institute at the University of Arkansas for Medical Sciences. One eye of each patient was randomized for study. The pupil size, visual acuity (VA) using the Early Treatment Diabetic Retinopathy Study (ETDRS) acuity chart, and glare testing with the Brightness Acuity Tester (BAT) at the medium setting were performed. The patients' eyes were then dilated with all measurements repeated. Each patient was then graded for cataracts using the Lens Opacification Classification System III by an independent observer. VA and BAT results. Compared with undilated BAT results, 29 of 54 patients (53.7%) lost 1 or more lines of vision during BAT testing after dilation. Undilated BAT results were predicted to within 1 line of accuracy in 44 of 54 patients (81.5%) by adjusting the dilated BAT result by the change in VA from dilation. With this method, results were predicted to within 2 lines of accuracy in 52 of 54 patients (96.3%). BAT results are affected by dilation half of the time and can be adjusted by the change in VA from dilation to predict undilated BAT results.

The effect of pupil dilation on driving vision in Canada

Background: To determine whether there is a clinically significant reduction in visual acuity (VA) or contrast sensitivity (CS), with and without glare, following examination with pupil dilation in patients currently driving.Methods: From November 1, 2004, to February 28, 2005, 105 consecutive patients were assessed in our institution.The better eye was assessed pre- and post-dilation with and without glare administered through the Brightness Acuity Tester. VA was assessed using the Early Treatment in Diabetic Retinopathy Study (ETDRS) and Snellen charts. CS was measured using the Vistech VCTS 6500 Chart.Results: With no glare, there was a mean reduction of 4.8 letters read from the ETDRS chart following dilation (p < 0.001). With glare, there was a mean reduction of 7.1 letters (p < 0.001). Compared with patients with initial VA of 20/20, patients presenting with a Snellen VA of 20/25 to 20/40 had a 9.75 relative risk of postdilation VA worse than 20/40, whereas patients with initial VA of 20/40 had a 19.8 relative risk of postdilation VA worse than 20/40. With the addition of glare, these relative risks increased to 13.9 and 28.8, respectively. Without glare, there was a significant reduction in CS after dilation at spatial frequencies of 2.0, 4.0, and 6.0 cycles/degree (p = 0.014, p < 0.001, and p < 0.001, respectively). With glare, there was a greater reduction in CS at these 3 spatial frequencies (p < 0.001 for all).Interpretation: There is a significant reduction in VA and CS after dilation that is further confounded by the effect of glare. This reduction may limit some patients from driving after dilation.

Visual Performance of Subjects Wearing Presbyopic Contact Lenses

The purpose of this study is to assess the visual performance of subjects wearing gas-permeable (GP) multifocal contact lenses, soft bifocal contact lenses, GP monovision lenses and spectacles. The study included 32 subjects between the ages of 42 and 65 years wearing GP monovision, the Acuvue Bifocal (Vistakon), the Essentials GP Multifocal (Blanchard), and progressive addition lenses (PAL; spectacles group). There were eight subjects in each of these groups who were already wearing these modalities. Binocular low (18%) and high (95%) contrast acuities were recorded using the Bailey-Lovie chart; binocular contrast sensitivity from 1.5 to 18 cycles per degree (cpd) measured with the Vistech VCTS 6500 system, and monocular glare sensitivity at three luminance settings (400, 100, and 12 foot lamberts) was measured using the brightness acuity tester (BAT). Binocular near visual task performance (a modified version of letter counting method used in previous presbyopic studies) was also assessed. For the contact lens-wearing groups, subjects wearing GP multifocals provided the best binocular high and low contrast acuity followed by soft bifocal wearers. There was relative parity between the binocular high and low contrast acuity with PAL and GP multifocal wearers. Monovision acuity, measured binocularly, was determined to be lower than the other three groups with this difference being most significant with high contrast acuity. Among contact lens-wearing groups, it was observed that GP multifocal lens wearers experienced the lowest amount of monocular disability glare followed by soft bifocal wearers and monovision wearers. Subjects wearing soft bifocal lenses and monovision demonstrated slightly reduced binocular contrast sensitivity at all spatial frequencies. In the contact lens groups, GP multifocal lens wearers had the highest binocular contrast sensitivity at all spatial frequencies, on parity with PAL wearers, except at the highest spatial frequency (18 cpd) at which PAL wearers had better vision. Error scores for the binocular near visual task performance between the four groups revealed subjects with GP multifocal lenses and PAL wearers to have the least errors, followed by monovision users and then soft bifocal wearers with the most errors. Subjects wearing GP multifocals, soft bifocals, monovision, and PAL spectacles have good binocular contrast sensitivity, satisfactory binocular low and high contrast acuity, and increased sensitivity to glare. Presbyopic subjects requiring the use of contact lenses under dim light levels could benefit from GP multifocal lenses. Contrast and glare sensitivity evaluations provide significant information regarding the visual performance of the presbyopic contact lenses and should be included in regular presbyopic contact lens fitting.

Glistenings in the AcrySof intraocular lens: pilot study

Purpose To evaluate the prevalence, severity, and visual significance of glistenings seen in the AcrySof® intraocular lens (IOL) and determine whether a large in-depth study of this lens is warranted. Setting John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Methods Patients who had the AcrySof IOL implanted at 1 institution over the past 4 years were serially selected. Forty-two eyes that had phacoemulsification with implantation of the AcrySof IOL were evaluated. The examination consisted of visual acuity, glare, contrast sensitivity, and dilated fundus and dilated slitlamp evaluations. Glistenings in the IOL were graded at the slitlamp from trace to 4+. Results All 42 IOLs had some degree of lenticular glistenings. The glistenings were graded as trace in 27 IOLs (64%), 1+ in 5 (12%), 2+ in 5 (12%), 3+ in 3 (7%), and 4+ in 2 (5%). The Snellen acuity in eyes with severe glistenings (≥2+) was one-half line lower than in eyes with mild glistenings (+) ( P = .01). In all eyes, the Brightness Acuity Tester score was a little more than one-half line lower than the Snellen acuity, and the difference was 1 full line in eyes with glistenings graded above 2+. Fourteen of 15 IOLs (93%) with glistenings graded greater than trace had been in the eye for more than 1 year. There was no evidence that contrast sensitivity was affected by the glistenings. Conclusions Glistenings occurred frequently in AcrySof IOLs, with most cases mild. A larger study of this lens is needed to determine whether severe presentations affect visual function and to understand how glistenings change over time.

Phototherapeutic keratectomy (PTK) after epidemic keratoconjunctivitis

Persistent and recurrent nummuli after epidemic keratokonjunktivitis (EKC) often lead to reduced visual acuity and increased glare. In spite of long-term topical steroid therapy nummuli often recur. We tried to treat persistent nummuli with phototherapeutic keratectomy (PTK). PTK with an excimer laser (193 nm) was performed in 13 eyes of 9 patients with nummuli. The nummuli were observed over 3-72 months (mean: 36 months). Preoperatively, the visual acuity was 0.1-0.9 (mean: 0.39 +/- 0.22) and the brightness acuity test (BAT) was 0.05-0.5 (mean: 0.25 +/- 0.15). Prior to PTK all eyes had been treated with local steroids several times for recurrent nummuli. During the follow-up from 15 to 56 months (mean: 33 +/- 11.5 ms), 11 eyes had an increase in visual acuity: 0.3-1.0 (mean: 0.63 +/- 0.26). The reduction of glare was especially beneficial for the patients: 0.3-0.9 (mean: 0.55 +/- 0.21). One patient had a recurrence of nummuli in both eyes 6 weeks after PTK. The subjective-induced spheric refractive change was -2.5 D to +2.0 D. The astigmatic error changed between -2.0 D to +1.5 D. PTK seems to be an effective method of treating persistent, recurrent nummuli after EKC. The low rate of recurrence of nummuli after PTK is remarkable.

Comparison of methods to assess visual impairment from glare and light scattering with posterior capsule opacification

Purpose: To compare 2 glare tests to determine their relative usefulness in the assessment of posterior capsule opacification (PCO) and to evaluate the potential benefits of combined visual acuity, contrast sensitivity, and glare testing.Setting: Teaching hospital ophthalmology department.Methods: Sixteen patients had glare, visual acuity, and contrast sensitivity testing before and after neodymium:YAG (Nd:YAG) capsulotomy. Results with the Brightness Acuity Tester (BAT, Mentor), which measures disability glare, and the Straylightmeter (Foundation for Eye Research, The Netherlands), which quantifies forward scatter by direct compensation techniques, were compared. The correlation between glare, ETDRS visual acuity, and Pelli-Robson contrast sensitivity was determined.Results: Pretreatment visual acuity was significantly correlated with contrast sensitivity (P < .01). However, visual acuity and contrast sensitivity were poorly correlated with both the BAT and Straylightmeter (P > .05), indicating that visual acuity is predictive of contrast sensitivity but a poor predictor of glare. Glare was significantly improved (Straylightmeter, P < .0001; BAT, P < .05) following capsulotomy. While the Straylightmeter consistently measured precapsulotomy forward scatter that improved with treatment, corresponding BAT disability glare was unmeasurable in 18.8% of patients with PCO, as their visual acuities improved rather than deteriorated with glare testing.Conclusions: Glare testing provided more information than contrast sensitivity when combined with visual acuity in the evaluation of PCO. Glare related to PCO is better assessed using the Straylightmeter because the BAT may yield aberrant disability glare results.

Visual performance requirements for post‐PRK police recruits

Background: New Zealand Police regulations (1996) allow the unaided visual acuity requirement of 6/12 to be achieved following refractive surgery (except radial keratotomy or keratoplasty) provided applicants also achieve normal (95 per cent confidence limit data from the literature): glare disability, contrast sensitivity, and low luminance visual acuity, one year or more after treatment.Methods: To confirm the limits adopted, 80 young normal adults were subjected to the tests in the regulations. To examine the operation of the current standards, the results of 34 post‐photorefractive keratectomy (post‐PRK) police applicants are reported. Glare disability was the loss of high contrast visual acuity (VA) with the Mentor Brightness Acuity Tester at medium intensity. Contrast sensitivity (CS) was examined using both Melbourne Edge Test thresholds and the VA difference between high and low contrast Bailey‐Lovie charts. Low luminance VA was measured using high contrast Bailey‐Lovie charts viewed through a one per cent transmittance filter.Results: The 95 per cent confidence limits found for normal performance were as follows. Glare disability: no more than 10 letters worse than VA without glare. Contrast sensitivity: no more than 12 letters difference between high contrast and low contrast letter acuity together with an edge contrast threshold of not less than 20 dB (CS = 100). These results were close to the values adopted for the current standard. The 95 per cent confidence limit for low luminance VA was a loss of 24 letters (almost five lines) and not the three lines of loss estimated from the literature. Two of the 34 post‐PRK applicants failed. One was unable to achieve 6/6 acuity with best refraction. The second could not meet the low luminance VA limit (loss no more than three lines). No failures have been due to glare disability or poor contrast sensitivity even though one applicant had obvious corneal haze.

Contrast sensitivity and glare disability with diffractive and refractive multifocal intraocular lenses

Purpose: To compare contrast sensitivity and glare disability provided by diffractive and refractive multifocal intraocular lenses (IOLs).Setting: University Eye Clinic Vienna, Austria.Method: This study evaluated the contrast sensitivity and glare disability in 29 eyes with a diffractive multifocal IOL (3M815LE) and 12 with a three-piece, five-zone refractive multifocal IOL (AMC Array SSM 26 NB). The Brightness Acuity Tester (Mentor, Inc.) was used with stationary sinusoidal gratings at spatial frequencies of 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd) generated on a television monitor (Nicolet CS 2000).Results: The contrast sensitivity functions of both multifocal IOL groups were within the reference range and were identical at 0.5, 1, and 22.8 cpd spatial frequencies. At 3, 6, and 11.4 cpd, the contrast sensitivity function in the diffractive IOL group was 6, 9, and 10% lower than in the refractive IOL group, and the difference between groups was statistically significant at 6 cpd. When glare was present, contrast sensitivity in the diffractive IOL group was generally in the lower limit of the reference range and remained below at 3 and 6 cpd. Contrast sensitivity in the refractive IOL group remained below the reference range at 3 cpd. At 0.5 and 1 cpd, there were no differences between the groups. At the middle and high spatial frequencies (3, 6, 11.4, 22.8 cpd), contrast sensitivity in the diffractive group was 8, 16, 11, and 12% lower than in the refractive group. At 6 cpd, the between-group difference was statistically significant.Conclusion: Diffractive multifocal IOLs provided decreased contrast sensitivity and greater glare disability than refractive multifocal IOLs.

AMO Array multifocal versus monofocal intraocular lenses: Long-term follow-up

Purpose: To assess prospectively the visual outcomes of multifocal and monofocal intraocular lens (IOL) implantation in selected patients with a minimum follow-up of 18 months.Setting: Department of Ophthalmology, National Health Service (INSALUD), Puerta de Hierro University Clinic, Madrid, Spain.Methods: This prospective study comprised two groups of 50 eyes each: one with AMO Array multifocal IOLs and the other with monofocal IOLs. Main outcome measures were Snellen and Regan 96% distance visual acuities; Jaeger and decimal near acuities; Regan contrast sensitivity test at 96, 50, 25, and 11%; brightness acuity test (BAT) on distance acuity at Regan 96%; depth of focus measured with the Regan 96% distance test; defocusing from +3s to −4s; subjective evaluation of optical side effects.Results: The differences between groups in mean distance vision and BAT results were not statistically significant. Contrast sensitivity results at 96 and 50% were similar, but there were significant differences of 0.94 and 1.14 lines on the 25 and 11% charts, respectively (P < .01). Near vision without addition in the multifocal group was significantly better and depth of focus significantly wider than in the monofocal group (P < .001).Conclusion: With appropriate patient selection, the AMO Array IOL provided distance acuity and contrast sensitivity similar to that of the monofocal IOLs and excellent intermediate vision. Near vision, without spectacles, with the multifocal lens was functionally acceptable although short of refractive power for best acuity results.

Evaluation of Visual Function Following Neodymium:YAG Laser Posterior Capsulotomy

Improvement in visual acuity is the primary endpoint for successful neodymium:YAG (Nd:YAG) laser posterior capsulotomy for posterior capsule opacification. There is limited information on related parameters of visual function that may also improve after laser treatment. The authors evaluate changes in contrast sensitivity and glare disability, aside from visual acuity, following Nd:YAG laser posterior capsulotomy. Measurements of visual acuity, contrast sensitivity (using the Pelli-Robson chart), and glare disability (using the Brightness Acuity Tester [Mentor O & O, Inc., Norwell, MA]) were obtained from 24 consecutive patients before and after Nd:YAG laser posterior capsulotomy. Glare testing was done with both the Pelli-Robson and Early Treatment Diabetic Retinopathy Study (ETDRS) charts. The degree of glare disability was indicated by the difference between visual function with glare (at medium and high settings) and without glare. Prelaser measurements were taken within 2 weeks prior to treatment, and postlaser measurements were obtained within 3 months after treatment. Only one eye per patient was evaluated. Mean differences between prelaser and postlaser measurements were significantly different from zero: (1) Contrast sensitivity, mean difference = 0.24 log units (P < 0.0001); (2) High glare disability using Pelli-Robson chart, mean difference = 0.15 log units (P = 0.004); (3) Visual acuity using ETDRS chart, mean difference = 11 letters (P < 0.0001); 4) High glare disability using ETDRS chart, mean difference = 7 letters (P = 0.005). Using the above methods for visual function testing, Nd:YAG laser capsulotomy is shown to significantly improve visual acuity, contrast sensitivity, and glare disability measurements as compared with prelaser values. The ophthalmologist may find it helpful to document the last two measurements prior to Nd:YAG laser capsulotomy, especially in patients who have good visual acuity but complain of glare sensitivity.

Study into the efficacy of a refractive multifocal intraocular lens implant

In the last decade there has been a significant advance in the types and materials of intraocular lens implants available. Recently, there has been a trend towards developing a multifocal intraocular lens (IOL) implant and, with advances in surgical techniques, there is the possibility of abolishing the need for postoperative spectacle correction completely. For the last seven years at the Croydon Eye Unit we have been involved in four multicentre clinical trials into the efficacy of the bizonal refractive form of multifocal IOL design. The results presented focus on the IOLAB 8191M multifocal implant, with a near central zone of 1.5 mm diameter, and a +4.00 D addition. When implanted, this is equivalent to a spectacle addition of +2.80 D.The surgical technique used was phacoemulsification with capsularrhexis, but incision size had to be increased to 6.0 mm in order to insert the IOL. However, postoperative corneal astigmatism was still well controlled, and this returned to preoperative values in 82% patients within 5 weeks. From previous studies we found that patients with a preoperative corneal astigmatism of &lt;1.00 D performed significantly better postoperatively (study inclusion criteria specific &lt;2.00 D of corneal astigmatism for patient qualification). To data, 245 8191M multifocals have been implanted in Europe, 228 of which have had a minimum of 3 months follow‐up. At our centre, 47 eyes have been implanted with the 8191M, 85% of whom have had at least a 12 month postoperative follow‐up.Our results have shown 64% patients achieving unaided visions of 6/12 or better for distance, and 84% J3 or better for near. In 45 eyes, acuity measurements with the distance correction in place indicates that 100% of eyes achieved 6/12 or better for distance, and 96% J3 or better for near. The effects of glare, tested with the Brightness Acuity Tester (BAT), showed no significant detrimental effect on visual acuity, and this was also shown to be independent of pupil size.In summary, the refractive design of multifocal IOL has been shown to give successful visual results. However, in order to achieve excellent results from multifocal designs of IOL, it is essential to have an astigmatically neutral form of surgery and accurate biometry.

Visual properties of the foldable Array multifocal intraocular lens

Purpose: To evaluate visual acuity, depth of focus, contrast sensitivity, and glare disability in eyes with an Array SSM 26-NB three-piece, five-zone multifocal intraocular lens (IOL).Setting: University Eye Clinic, Vienna, Austria.Method: Fourteen eyes with an AMO Array IOL were evaluated for uncorrected and best corrected distance and near visual acuity. The reading distance produced by the near focus of the lens was varied with convex glasses of less power. Reading at distance focus was evaluated by adding +3.50 diopters (D) to the distance correction. Depth of focus was measured from -3.00 to +6.00 D. Contrast sensitivity and glare disability were also measured using the Brightness Acuity Tester with stationary sinusoidal gratings at 0.5, 1, 3, 6, 11.4, and 22.8 cycles/degree.Results: Mean uncorrected distance acuity (Snellen) was 0.79 ± 0.17 (SD), which increased to 0.94 ± 0.14 with best correction. Near acuity was J2.75 ± 1.35 and J2.59 ± 1.10, respectively. When near focus was tested for reading distance, a mean of +0.54 ± 0.02 D was accepted for improvement of near vision of J1.71 ± 0.94. Near acuity with a distance focus addition of +3.50 D was J1.08 ± 0.28. Contrast sensitivity and glare disability were lower than in 13 eyes with a monofocal poly(methyl methacrylate) IOL and 16 normal phakic eyes.Conclusions: Eyes with the Array IOL had full distance function. Reading performance could be improved with a near focus of more than +3.50 D. Full near vision could be achieved with the distance focus and conventional reading glasses. Depth of focus was sufficient but visual acuity was limited at intermediate and near distance. Although contrast sensitivity was relatively low, it was not beyond the reference range.