Preschool vision screening: negative predictive value for amblyopia

BACKGROUND/AIMS: Single optotype tests of visual acuity are widely used for preschool vision screening in order to optimise cooperation with testing. These tests may, however, underestimate the visual acuity deficit in amblyopia because they lack visual crowding. This study assessed the resultant negative predictive value (NPV) for amblyopia. METHODS: Cohort study of 936 children in the Cambridge Health District selected by date of birth. The presence of amblyopia among children who had passed preschool vision screening was determined using Snellen line acuity as the reference test. Preschool vision screening was conducted at 3.5 years of age by community orthoptists. The screening assessment comprised Sheridan-Gardiner single optotype test of visual acuity (referral criterion 6/9 or worse in either eye), cover test, ocular movements, 20(Delta) prism test, and TNO stereotest. RESULTS: The overall NPV of preschool vision screening for amblyopia was 100% (95% CI 99.4% to 100%). Most children with amblyopia were detected by the Sheridan-Gardiner single optotype test of visual acuity, but the other screening tests were necessary to prevent any false negatives. In isolation, the Sheridan-Gardiner single optotype test of visual acuity has a NPV for amblyopia of only 99.6% (95% CI 98.7% to 99.9%). CONCLUSION: Preschool vision screening using a single optotype test of visual acuity does achieve a high NPV for amblyopia, but only under certain conditions. These comprise a low threshold for referral (6/9 or worse in either eye) and the inclusion of a cover test and tests of binocular function in the screening assessment.     

The impact of light source on discrimination ability in subjects with age‐related macular degeneration

Purpose: To examine the influence of light source on letter contrast sensitivity in subjects with age‐related macular degeneration (AMD). Methods: Halogen incandescent bulbs and low‐energy fluorescent tubes were tested with 70 subjects with AMD. The subjects’ contrast sensitivity was determined in a randomized single‐blind crossover study for each light source using photopically illuminated Pelli Robson contrast sensitivity charts. The test subjects’ subjective light source preference was also determined. Results: The mean contrast sensitivity for the incandescent light source was 1.28 ± 0.29 (mean ± SD), and for the fluorescent light source 1.17 ± 0.29, p < 0.001. The illuminance was 338 lux (±9) for the incandescent light, and 339 lux (±11) for the fluorescent light. Forty‐nine subjects preferred the incandescent light source, while none preferred the fluorescent light source for maximum detail and clarity. Nineteen had no preference. This finding is statistically significant. Fifteen of the 19 subjects without a preference had no difference in contrast sensitivity, which supports their lack of preference. There was no significant difference with regard to sex or order of exposure to light source. Subjects with AMD had significantly reduced contrast sensitivity compared with expected normal values. We found no relationship between visual acuity and contrast sensitivity. Conclusion: We are only able to recommend photopic full spectral radiance incandescent light sources to visually impaired subjects for their domestic surroundings. Furthermore, we recommend the use of full spectral radiance light sources for the illumination of Pelli‐Robson contrast sensitivity charts. Given equal illuminance, as in our study, the findings show that contrast sensitivity was better by illumination with incandescent light with full spectral radiance compared with fluorescent light with interrupted spectral radiance.     

Measurement of apparent accommodation with a 20/20 near vision optotype

PURPOSE: The value of apparent accommodation varies with methods of measurement. To discuss the details of apparent accommodation, it is appropriate to measure it with the smallest possible near vision optotype. In the present study, we used a 20/20 near vision optotype for the measurement of apparent accommodation. SUBJECTS AND METHODS: Forty-six eyes of thirty-eight patients (45-84 years old) who had undergone cataract surgery and intraocular lens implantation, and had at least 20/20 best corrected visual acuity at near and far distances, were used in this study. After the eyes were corrected by glasses to gain the best corrected long distance visual acuity, they were forced to watch a 20/20 near vision optotype. Then we gradually added plus lenses until they could recognize the optotype. The value of apparent accommodation was recorded by subtracting the value of plus lens by which the eye could first recognize the 20/20 near vision optotype from three diopters. RESULTS: The value of apparent accommodation was 0.00-3.00 D (medium 0.50 D). Two eyes had three diopters of apparent accommodation. CONCLUSION: In the present study with correction of astigmatism and small near vision optotype, most eyes showed smaller apparent accommodation than those in previous studies. Despite that, patients with three diopters of apparent accommodation do exist. To analyze high quality visual functions, we should use the smallest possible near vision optotype for the measurement of apparent accommodation.     

Far and near visual acuity with multifocal intraocular lenses in an optomechanical eye model with imaging capability

PURPOSE: To compare the quantitative and qualitative visual performances of different multifocal intraocular lenses (IOLs) in an experimental model of the human eye. SETTING: University Hospital San Raffaele, Milan, Italy. METHODS: Five multifocal IOLs and 1 monofocal IOL were implanted in an optomechanical eye model with imaging capability. The comparative optical characterization of the imaging performance included aberrometry, simulated visual acuity testing at variable contrast for far and near distance, glare tests, and image records of optotype charts. RESULTS: The maximum recorded far visual acuity for the monofocal IOL was between 20/12.5 and 20/16; the multifocal IOLs decreased visual acuity by 1 to 2 lines. The difference tended to increase at reduced contrast. Full-contrast near visual acuity with multifocal IOLs ranged between 20/63 and 20/25; the near distance performance of the monofocal IOL without an additional correcting lens was worse by 1 to 3 lines of acuity with large pupils but was comparable with small pupils. Multifocal IOLs of different designs showed marked differences as a function of contrast, which tended to balance between far and near behaviors. CONCLUSIONS: Multifocal IOLs of different optical designs were well characterized and distinguished by simulated contrast acuity testing in an experimental eye model, allowing quantitative comparison. Their overall visual performance, averaged over contrast and distance, was not superior to the performance of a monofocal IOL without an additional correcting lens.     

Detection of nonorganic visual loss with a new optotype chart in simulated malingerers

BACKGROUND: We tested a new distance and pocket optotype chart for detection of nonorganic symmetrically decreased vision in simulated malingerers. The new optotype used in the charts is based on a subjective contour formed by a misalignment of two line segments. The minimum angle of resolution of this optotype is independent of its size. Subjects claiming to see only the larger optotypes are suspected of malingering. SUBJECTS AND METHODS: 90 normal subjects were asked to simulate symmetrically decreased vision. 60 of these subjects were tested with a distance chart and 30 with a pocket chart. The distance chart was always presented at a fixed distance of 5 m. The pocket chart was moved towards the malingerer until the largest optotype was clearly legible. RESULTS: With the distance chart, 62 % (37/60) of all simulated patients claimed to recognize only the larger optotypes, 33 % (20/60) claimed not to recognize any optotype size, and 5 % (3/60) were able to read all optotype sizes. With the pocket chart, 84 % (25/30) of all simulated patients claimed to recognize only the larger optotypes, 3 % (1/30) claimed not to recognize any optotype size, and 13 % (4/30) were able to read all optotype sizes. The difference between the two distributions of behavior was statistically significant (chi-square statistic, P < 0.005). CONCLUSIONS: Movement of the chart towards the subject (pocket chart) was better at detecting nonorganic visual loss than using a fixed distance (distance chart). Therefore, we suggest to use the pocket chart for the detection of nonorganic disease.     

The influence of ocular dominance on monovision--the interaction between binocular visual functions and the state of dominant eye's correction

PURPOSE: To examine the interaction between binocular visual functions and the correction of the dominant eye, i.e., for far vs. near vision in monovision. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmological disease were examined. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses (difference in lens power between the lenses: 2.5 D) with an artificial pupil(diameter: 3.0 mm). Visual acuity at various distances, contrast sensitivity, and near stereoacuity were measured while the dominant eye determined by the hole-in-card test (sighting dominance) was corrected for far and near vision. RESULTS: Binocular visual acuity was better than 1.0(20/20) at all distances. When the dominant eye was corrected for distance, the binocular visual acuity at 0.7 m was better than the monocular visual acuity; contrast sensitivity was better within the spatial frequency range of 0.5-4.0 cycles per degree, and near stereoacuity by Titmus stereo tests improved. CONCLUSION: These results suggest that dominant eyes should be corrected for far vision for better binocular summation at middle distances, and near stereoacuity.     

Eye dominance in the visual cortex using functional MRI at 1.5 T: an alternative method.

PURPOSE: To develop a functional MRI method for producing eye dominance histograms in humans at 1.5 Tesla (T). METHODS: In the first set of experiments, 8 normal persons were tested. The eye dominance of each voxel within the person's visually activated primary visual cortex was determined with Student t statistics during a left eye versus right eye contrast. Eye dominance distribution was plotted, and the mean t statistic was used to describe the histogram asymmetry. In the second set of experiments, the effect of monocular optical blur and decreased luminance via filter was studied, and eye dominance distributions were similarly determined. RESULTS: The eye dominance histogram in each of the 8 normals was approximately symmetric; the average mean t value was +0.13. All 4 subjects with the right eye blurred had histograms approximately symmetric or slightly shifted toward the left eye (average mean t = +0.56), and all 4 subjects with the right eye filtered had histograms dramatically shifted toward the left eye (average mean t = +2.22). The average mean t for the group with the right eye filtered was significantly different from that of the other 2 groups (P <.0001). CONCLUSIONS: With noninvasive methods in normal persons, functional magnetic resonance imaging techniques at 1.5 T were able to characterize the distribution of eye dominance of voxels in primary visual cortex, based upon their t statistic in the left eye versus right eye contrast. The method is sensitive to filtering but relatively insensitive to visual blur. This approach may have a future use in the study of amblyopia in humans.     

Occlusion and levodopa-carbidopa treatment for childhood amblyopia.

PURPOSE: The purpose of the current study was to compare the effects of levodopa-carbidopa with and without part-time occlusion on visual function in older amblyopic children. METHODS: Thirteen older amblyopic children were randomly assigned to receive or not receive part-time occlusion (3 h/day) combined with 7 weeks of oral dosing with levodopa-carbidopa (1.02 mg/0.25 mg/kg body weight three times daily). Visual acuity, contrast sensitivity, and fusion were measured at baseline; 1, 3, 5, and 7 weeks during the treatment regimen; and 4 weeks after termination of all treatment. At these same times health status was assessed with standard laboratory blood tests, physical examination, and subjective questionnaire. RESULTS: From baseline to the follow-up test trial, both groups improved in visual acuity in the amblyopic eyes (occlusion group 20/116 to 20/76, P < .001; no occlusion group 20/90 to 20/73, P < .01) and dominant eyes (occlusion group 20/18 to 20/15, P > .05; no occlusion group 20/20 to 20/16, P < .01). The occlusion group exhibited a significant decrease in the difference in acuity between the dominant and amblyopic eyes of 1.3 lines (P < .02), whereas the no occlusion group revealed no significant effect. A comparison between groups revealed a significantly greater improvement in visual acuity in the amblyopic eye in the occlusion group compared with the no occlusion group (P = .01). In contrast, there was no significant difference between groups in terms of the change in visual acuity in the dominant eye (P = .15). Mean log contrast sensitivity in the amblyopic eye significantly improved in the occlusion group and did not significantly change in the no occlusion group. Fusion changed similarly in both groups. The improvements in visual function were maintained 4 weeks after the termination of all treatment. Adverse side effects were minimal in both groups. CONCLUSION: The combination of levodopa-carbidopa and occlusion improves visual function more than levodopa-carbidopa alone in older amblyopic children.     

Optomechanical eye model with imaging capabilities for objective evaluation of intraocular lenses

PURPOSE: To develop an in vitro procedure providing data on the visual performance obtainable with intraocular lenses (IOLs), for objective comparison between IOL models and direct correlation with the relative visual performance attainable in vivo. SETTING: University Hospital San Raffaele, Milan, Italy. METHODS: An optomechanical eye model was developed to allow simulated in vivo testing of IOLs. The experimental eye mimics the optics and geometry of the Gullstrand's eye model, with an aspheric poly(methyl methacrylate) cornea, variable pupil, and IOL holder. Its detection system is designed to reproduce the mean resolution of the human fovea. The imaging capabilities of the model eye were measured using monofocal IOLs. The tests included qualitative information, such as appearance of optotype chart images, and quantitative information, such as simulated visual acuity tests for far and near distance at variable contrasts. RESULTS: Objective numerical IOL evaluation was made possible on the basis of the visual acuity recorded with the eye model. The maximum recorded far acuity for the monofocal IOLs was about 20/14 at full contrast, progressively decreasing for reduced contrast. Best corrected near acuity ranged between 20/14.7 and 20/15.4. CONCLUSIONS: The optomechanical eye model provided objective grading of IOLs through the evaluation of simulated visual acuity, which can be scaled usefully to human vision. The eye model also allowed the qualitative visualization of IOL imaging properties, making it potentially useful in characterizing and distinguishing different IOL types.     

A new optotype chart for detection of nonorganic visual loss

OBJECTIVE: To develop a new optotype chart for detection of nonorganic decreased vision. DESIGN: Comparative observational case series. PARTICIPANTS: Optotype thresholds determination in three normal subjects and testing on 30 consecutive patients with unclear visual acuity loss. METHODS: A new optotype chart was developed, with an optotype minimum angle of resolution that is independent of size. In three normal subjects rank correlation was calculated between the optotype thresholds and the optotype sizes. A pocket chart was tested in a masked manner on 30 consecutive patients referred because of unclear visual acuity loss. MAIN OUTCOME MEASURES: Optotype thresholds and usefulness in clinical routine (positive and negative predictive values including 95% confidence intervals [CI]). RESULTS: The optotype thresholds did not correlate with the optotype sizes. Ten percent (3 of 30) of the patients referred because of unclear visual acuity loss had to be excluded, because their diagnosis remained unclear. All patients (16 of 16) with organic visual loss saw all optotypes sizes. Eighty-nine percent (10 of 11) of patients with nonorganic visual loss claimed to see only the larger optotypes. The positive predictive value for nonorganic visual loss of the new pocket chart was 100% (CI, 74%-100%); the negative predictive value was 94% (CI, 75%-100%). CONCLUSIONS: The new pocket chart seems to be useful for detection of visual loss caused by nonorganic disease.     

Association between Ocular Dominance and Spherical/Astigmatic Anisometropia, Age, and Sex: Analysis of 1274 Hyperopic Individuals

Purpose. To determine the association between ocular dominance and spherical/astigmatic anisometropia, age, and sex in hyperopic subjects. Methods. The medical records of 1274 hyperopic refractive surgery candidates were filtered. Ocular dominance was assessed with the hole-in-the-card test. Refractive error (manifest and cycloplegic) was measured in each subject and correlated to ocular dominance. Only subjects with corrected distance visual acuity of >20/22 in each eye were enrolled, to exclude amblyopia. Associations between ocular dominance and refractive state were analyzed by means of t-test, χ(2) test, Spearman correlation, and multivariate logistic regression analysis. Results. Right and left eye ocular dominance was noted in 57.4 and 40.5% of the individuals. Nondominant eyes were more hyperopic (2.6 ± 1.27 diopters [D] vs. 2.35 ± 1.16 D; P < 0.001) and more astigmatic (-1.3 ± 1.3 D vs. -1.2 ± 1.2 D; P = 0.003) compared to dominant eyes. For spherical equivalent (SE) anisometropia of >2.5 D (n = 21), the nondominant eye was more hyperopic in 95.2% (SE 4.7 ± 1.4 D) compared to 4.8% (1.8 ± 0.94 D; P < 0.001) for the dominant eye being more hyperopic. For astigmatic anisometropia of >2.5 D (n = 27), the nondominant eye was more astigmatic in 89% (mean astigmatism -3.8 ± 1.1 D) compared to 11.1% (-1.4 ± 1.4 D; P < 0.001) for the dominant eye being more astigmatic. Conclusions. The present study is the first to show that the nondominant eye has a greater degree of hyperopia and astigmatism than the dominant eye in hyperopic subjects. The prevalence of the nondominant eye being more hyperopic and more astigmatic increases with increasing anisometropia.     

Effects of dominant and nondominant eyes in binocular rivalry.

PURPOSE: To investigate the relation between sighting and sensory eye dominance and attempt to quantitatively examine eye dominance using a balance technique based on binocular rivalry. METHODS: The durations of exclusive visibility of the dominant and nondominant eye target in binocular rivalry were measured in 14 subjects. The dominant eye was determined by using the hole-in-card test (sighting dominance). In study 1, contrast of the target in one eye was fixed at 100% and contrast of the target in the other eye was varied from 100% to 80% to 60% to 40% to 20%, when using rectangular gratings of 1, 2, and 4 cycles per degree (cpd) at 2 degrees, 4 degrees , and 8 degrees in size. In study 2, contrast of the target in the nondominant eye was fixed at 100% and contrast of the target in the dominant eye was varied from 100% to 80% to 60% to 40% to 20%, when using a rectangular grating of 2 cpd at 4 degrees in size. RESULTS: In study 1, the total duration of exclusive visibilities of the dominant eye target; that is, the target seen by the eye that had sighting dominance was longer compared with that of the nondominant eye target. When using rectangular gratings of 4 cpd, mean total duration of exclusive visibility of the dominant eye target was statistically longer than that of the nondominant eye target (p < 0.05). In study 2, reversals (in which duration of exclusive visibility of the nondominant eye becomes longer than the dominant eye when the contrast of the dominant eye target is decreased) were observed for all contrasts except for 100%. CONCLUSIONS: The dominant sighting eye identified by the hole-in-card test coincided with the dominant eye as determined by binocular rivalry. The contrast at which reversal occurs indicates the balance point of dominance and seems to be a useful quantitative indicator of eye dominance to clinical applications.     

Illumination and reading performance in age‐related macular degeneration

Background: Previous studies have compared low vision reading performance at optimal task illuminance and consulting room illuminance (500 to 600 lux). However, it is uncertain the extent to which low vision reading performance can be improved when task illumination is increased from levels more representative of those found in the typical living room (50 lux) to levels likely to maximise performance. Methods: Reading performance of 20 subjects with age‐related macular degeneration (AMD) was assessed for a range of print sizes using sentence reading charts at six levels of task illuminance (50 to 5,000 lux). Subjects read without low vision devices. Results: Sentence reading acuity and critical print size improved by a factor of two over the 50 to 5,000 lux range, while maximum reading rate improved by a factor of 1.4. For the majority of subjects (70 per cent), the optimal task illuminance (determined objectively) was higher (median 3,500 lux) than the subjectively preferred task illuminance (median 2,450 lux). Reading performance was significantly better at the optimal illuminance than at illuminances equivalent to those found in the domestic environment (50 lux) or consulting room (600 lux). Conclusions: The majority of AMD patients will require task illumination of at least 2,000 lux to maximise reading performance. Optimal illumination should be determined individually for each patient using both objective measures of performance, such as reading acuity, and subjective assessments of visual comfort.     

Functional visual loss in amblyopia and the effect of occlusion therapy.

PURPOSE: The aim of this study was to define the nature of functional visual loss in amblyopia and to identify those subjects whose amblyopia is chiefly due to one or more of the following deficits: abnormal contour interaction, abnormal eye movements, abnormal contrast perception, or positional uncertainty. METHODS: Fifty amblyopic children with a mean age of 5.6+/-1.3 years were referred from diverse sources. In addition to routine orthoptic and optometric evaluation the principal visual deficits in the amblyopic eye of each subject were identified using the following measures of visual acuity: high contrast linear, single optotype, repeat letter and low contrast linear, plus Vernier and displacement thresholds. These measures were repeated as the children underwent a prescribed occlusion therapy regime, after parental consent. RESULTS: All amblyopic subjects demonstrated a functional loss in each of the tests used, and occlusion therapy appeared to improve all aspects of the amblyopia. High contrast visual acuity was not always the primary deficit in visual function, and when amblyopic subjects were divided according to their primary visual loss, this visual function was found to show the greatest improvement with treatment. CONCLUSIONS: These results suggest that to successfully identify the primary visual deficit and monitor the success of occlusion therapy it is necessary to assess other aspects of visual function in amblyopia.     

Contrast sensitivity in amblyopia: the fellow eye of untreated and successfully treated amblyopes.

PURPOSE: We sought to investigate contrast sensitivity on the fellow eyes of amblyopic and successfully treated amblyopic subjects. METHODS: Contrast sensitivity was tested monocularly on both eyes of 48 amblyopic patients (mean age, 11.51 years) and of 22 successfully treated amblyopic subjects (visual acuity 20/20 in each eye; mean age, 11.22 years). Inclusion criteria were visual acuity in the amblyopic eye 20/40 or better (mild amblyopia) and 20/20 or better in the fellow eye, steady fixation, no signs of congenital, latent or manifest/latent nystagmus on clinical examination. Twenty normal subjects (20 eyes) were used as age-matched controls. RESULTS: Contrast sensitivity functions from the fellow eye of the 48 amblyopic patients, even those who had never been treated with occlusion therapy before, were significantly decreased (P < 0.001) compared with control subjects. Both the previously amblyopic and the fellow eye of the 22 "cured" amblyopic subjects demonstrated significantly lower values (P < 0.001) compared with control patients. CONCLUSIONS: We suggest that the nonamblyopic, "normal" eye of amblyopic patients behaves abnormally when evaluated for contrast sensitivity functions. Neither the previously amblyopic nor the fellow eyes of successfully treated subjects were comparable with controls. Occlusion therapy may not be implicated for depressed contrast sensitivity of the fellow eye in amblyopia. The assessment of contrast sensitivity can provide important information on the visual function and the influence of occlusion therapy in amblyopia.     

The influence of ocular dominance on monovision--the influence of strength of ocular dominance on visual functions

PURPOSE: Monovision is a method of correction for presbyopia. We have reported the advantage of conventional monovision (the dominant eye is corrected for distance). In this study, we investigated the influence of interocular imbalance of dominancy on the visual function. SUBJECTS AND METHODS: Ten healthy subjects without any ophthalmologic disease participated. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses with an artificial pupil (diameter: 3.0mm). The dominant eye was corrected for distance, and the difference in lens power between the lenses was 2.5 D. The subjects were classified into two groups by strength of the imbalance of sensory dominance, which was determined by using binocular rivalry. Binocular visual functions (visual acuity at various distances, contrast sensitivity, near stereoacuity) were compared between the two groups. RESULTS: Subjects with strong imbalance of sensory dominance showed decreased near visual acuity as well as decreased binocular summation of contrast sensitivity at low spatial frequencies. On the other hand, near stereoacuity was not affected by the imbalance of sensory dominance. CONCLUSION: These results suggest that strong imbalance of sensory dominance interferes with binocular visual functions in monovision. Thus, the evaluation of ocular dominance is crucial for clinical applications of monovision.     

Comparison of reverse-geometry lens designs for overnight orthokeratology.

PURPOSE: The efficacy of overnight wear of four types of reverse-geometry lenses was compared. The length of time needed to achieve correction and any adverse events that occurred during the course of the study were recorded. METHODS: In this prospective, randomized study, 60 subjects (18 to 35 years old) with refractive error between -1.00 to -4.00 D (cyl 相似文献   

Association between ocular dominance and refraction

PURPOSE: To investigate the association between ocular dominance and refraction. METHODS: A retrospective study of the cycloplegic refraction of 2453 consecutive patients with a mean age of 46 +/- 12 years (range: 18 to 79 years) was performed. One thousand one hundred fifty-seven (47%) patients were men and 1296 (53%) were women. Patients who had previous eye surgery, ocular disease, or > 2 lines of best spectacle-corrected visual acuity (BSCVA) difference between eyes were excluded. Motor ocular dominance was determined using the hole-in-the-card test. RESULTS: The right and left eyes were dominant in 67% (1650) and 33% (803) of patients, respectively. Males had a higher right eye dominance (70%) than females (65%) (P = .0168) with a mean cycloplegic spherical equivalent refracton (SE) of -2.12 diopters (D) and -2.38 D, respectively. This higher rate of right eye dominance in males was seen at all levels of SE refractive error. Mean BSCVA was 20/19 in both right and left eyes (P>.05) with a mean SE of -2.25 +/- 3.63 D and -2.26 +/- 3.66 D in the right and left eyes, respectively. Neither mean SE difference nor BSCVA difference between eyes was found to correlate with motor eye dominance. CONCLUSIONS: Gender appears to be a factor when testing ocular dominance but not SE refractive error. The hole-in-the-card dominance test is a method that is easy to perform for both patients and clinicians.     

Binocular interactions in patients with age-related macular degeneration: acuity summation and rivalry

This study examined two aspects of binocular function in patients with age-related macular degeneration (AMD): summation/inhibition of visual acuity and rivalry. The performance of 17 patients with AMD was compared with that of 17 elderly controls and 21 young people. Monocular and binocular acuities were measured using a multiple-E optotype test. Binocular ratios, defined as the better-eye acuity divided by the binocular acuity, were calculated. We also measured eye dominance during rivalry (proportion of time the participants reported perceiving the input to each eye) and rivalry rates (number of alternations per minute). The results showed that while overall binocular ratios were similar for the three groups, the frequency distributions of people who experienced inhibition, equality or summation were different for the young and AMD groups. In the rivalry test, patients experienced more piecemeal perception than the elderly and young controls, but time dominance from the better-seeing eye was comparable for the three groups. Rivalry rates decreased with age and further with pathology. Moreover, rivalry time dominance of the worse-seeing eye was negatively correlated with interocular acuity differences for the AMD group.     

Effect of total higher-order aberrations on accommodation in pseudophakic eyes

PURPOSE: To analyze the effect of total higher-order aberrations (HOAs) on the range of accommodation in pseudophakic eyes and the size of near-vision optotypes. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: The study comprised 30 patients (44 eyes) who were diagnosed with cataract at Nara University of Medical Science Hospital and Municipal Oyodo Hospital. Inclusion criteria included no other eye disorder and a best corrected distance acuity of 20/20 or better 1 month after cataract surgery. All patients had small-incision phacoemulsification followed by in-the-bag implantation of a monofocal intraocular lens (SA60AT, Alcon). All incisions were self-sealing. Accommodation in pseudophakic eyes was measured by the lens-loading method in an examination room under constant illumination. Ocular HOAs were measured using the KR-9000PW Hartmann-Shack wavefront analyzer (Topcon). RESULTS: The mean patient age was 75.8 years +/- 5.4 (SD) (range 64 to 83 years). The Pearson correlation coefficient (r) showed a significant positive correlation between the range of accommodation and Z7 (vertical coma) for a 4.0 mm pupil using the 1.0 near-vision optotype. There was a significant negative correlation between the range of accommodation and Z12 (spherical aberration) for a 4.0 mm pupil using the 1.0 near-vision optotype (r = .311, P = .040 for Z7;r = -.365, P = .015 for Z12). No other parameter was significantly correlated with the range of accommodation. CONCLUSIONS: Measurement of accommodation in pseudophakic eyes by the lens-loading method using the 1.0 near-vision optotype showed that eyes with larger vertical coma aberrations achieved a larger range of accommodation. In contrast, eyes with larger spherical aberrations had smaller amounts of accommodation. The size of the near-vision optotype may affect accommodation analysis in pseudophakic eyes.