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Eileen E Birch - One of the best experts on this subject based on the ideXlab platform.
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visual Acuity development of children with infantile nystagmus syndrome
Investigative Ophthalmology & Visual Science, 2011Co-Authors: Richard A Bilonick, Joost Felius, Richard W Hertle, Eileen E BirchAbstract:PURPOSE. Infantile nystagmus syndrome (INS) can be idiopathic or associated with ocular or systemic disease. The ocular oscillation of INS directly contributes to loss of visual Acuity. In this study, visual Acuity development in patients with INS was examined. METHODS. Children with INS were classified as having idiopathic INS (n 84) or INS with an associated sensory deficit: INS and albinism (n 71), bilateral optic nerve hypoplasia (ONH; n 23), or congenital retinal disorder (n 36). Visual Acuity was assessed with Teller cards and/or optotypes, and the data were analyzed for three age groups (24 months, 24‐48 months, and 48 months). RESULTS. Patients with idiopathic INS showed mildly reduced visual Acuity early in life and gradual maturation with age that paralleled a normative curve. Patients with albinism also showed a mild visual deficit early in life but failed to keep pace with the normative curve, showing a gradual increase in visual Acuity deficit. Patients with ONH and congenital retinal disorders exhibited more severe visual Acuity deficits during infancy. The ONH group displayed slow improvement of visual Acuity with a plateau at 24 months through 48 months, with a small increase in visual Acuity deficit. The congenital retinal disorder group had no significant change in visual Acuity across age and had a rapid increase in visual Acuity deficit. CONCLUSIONS. The pattern of visual Acuity development differs among children with INS, depending on the presence or absence of associated sensory system deficits. Careful characterization of visual system differences in patients with INS is important if visual Acuity is an outcome in clinical trials. (Invest
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vernier Acuity cards examination of development and screening validity
Optometry and Vision Science, 2010Co-Authors: James R Drover, Sarah E Morale, Yizhong Wang, David R. Stager, Eileen E BirchAbstract:PURPOSE: Because vernier Acuity seems to be limited by the visual cortex, it possesses excellent potential as a clinical/screening tool to detect amblyopia in infants and toddlers. Thus, we developed the vernier Acuity cards specifically for this age group. We compared developmental data gathered using this new test and the Teller Acuity Cards. In addition, we compared the clinical/screening validity of the two tests by testing children old enough to complete optotype Acuity testing (6.2 ± 2.5 years). METHODS: Vernier Acuity and grating Acuity were assessed in 98 children and 18 adults with normal vision (age range = 2.8 months to 35.8 years). The developmental time course of the two visual functions was compared. In addition, vernier Acuity and grating Acuity were measured in 43 children with amblyopia and 30 nonamblyopic children with an amblyogenic condition. Each child's grating Acuity and vernier Acuity were classified as normal/abnormal based on age-appropriate norms. These classifications were compared with amblyopia diagnoses by crowded HOTV or Early Treatment Diabetic Retinopathy Study (ETDRS) testing. RESULTS: Vernier Acuity and grating Acuity follow different developmental time courses in normal infants and children. Vernier Acuity is initially poorer than grating Acuity but surpasses it by the age 5 years and is adult-like by the age 8 years. Compared with the Teller Acuity Cards, the vernier Acuity cards yielded higher sensitivity (81 vs. 44%) and similar specificity (73 vs. 93%) and were more sensitive to all amblyopia subtypes/levels of severity. CONCLUSIONS: The developmental time course of vernier Acuity differed from that of grating Acuity, implying that it is not mediated by the retina. Also, the impressive validity of the vernier Acuity cards suggests that they are an effective tool for detecting amblyopia.
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comparison of the amblyopia treatment study hotv and the electronic early treatment of diabetic retinopathy study visual Acuity protocols in amblyopic children aged 5 to 11 years
Journal of Aapos, 2009Co-Authors: Eileen E Birch, Samara F Strauber, Roy W Beck, Jonathan M HolmesAbstract:As part of the long-term follow-up of amblyopic children who were enrolled in the Amblyopia Treatment Study, we tested visual Acuity in both eyes of 142 patients by using 2 established visual Acuity protocols, the Amblyopia Treatment Study HOTV (ATS HOTV) visual Acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, at one of the annual visits. Mean age at the time of testing was 9.0 years (range, 5.6-11.9 years). The ATS-HOTV protocol resulted in a slight mean overestimate of visual Acuity relative to the E-ETDRS protocol (0.68 lines for amblyopic eyes; 0.25 lines for fellow eyes). The overestimation occurred primarily when the E-ETDRS visual Acuity was poorer than 0.3 logMAR. ATS-HOTV Acuity also underestimated interocular visual Acuity differences by 0.42 lines. When one uses the ATS-HOTV protocol, it may be wise to exercise caution when interpreting "near-normal" visual Acuity or interocular differences as "within normal" because the ATS-HOTV method may have a slight bias toward better performance of amblyopic eyes than E-ETDRS.
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normative pediatric visual Acuity using single surrounded hotv optotypes on the electronic visual Acuity tester following the amblyopia treatment study protocol
Journal of Aapos, 2008Co-Authors: James R Drover, Lauren M Wyatt, Christina S Cheng, Joost Felius, Sarah E Morale, Eileen E BirchAbstract:Purpose To provide normative pediatric visual Acuity data using HOTV optotypes presented on the Electronic Visual Acuity Tester following the Amblyopia Treatment Study (ATS) protocol. Methods Monocular testing was conducted on 384 healthy full-term children ranging from 3 to 10 years of age (mean, 5.4 years; SD, 1.8 years). A total of 373 children completed monocular testing of each eye. In addition, 23 adults (mean, 28.7 years; SD, 4.9 years) were tested for comparison. Both monocular visual Acuity and interocular Acuity differences were recorded. Results Mean visual Acuity improved by slightly more than one line (0.12 logMAR) from 3 years of age to adulthood, increasing from 0.08 logMAR to −0.04 logMAR ( F 6,400 = 26.3, p −26 ). At all ages, mean interocular Acuity difference was less than one line on a standard Acuity chart (overall mean difference=0.04 logMAR; SD, 0.06 logMAR). Conclusions These results represent the first normative data reported for HOTV optotypes using the ATS protocol on the Electronic Visual Acuity Tester. These data may play an important role in clinical practice, screening, and clinical research.
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computerized method of visual Acuity testing adaptation of the amblyopia treatment study visual Acuity testing protocol
American Journal of Ophthalmology, 2001Co-Authors: Pamela S Moke, Andrew Turpin, Michael X Repka, Raymond T Kraker, Roy W Beck, Eileen E Birch, Jonathan M Holmes, Richard W Hertle, Joseph M. Miller, Chris A JohnsonAbstract:PURPOSE: To report a computerized method for determining visual Acuity in children using the Amblyopia Treatment Study visual Acuity testing protocol. METHODS: A computerized visual Acuity tester was developed that uses a programmed handheld device that uses the Palm operating system (Palm, Inc, Santa Clara, California). The handheld device communicates with a personal computer running a Linux operating system and 17-inch monitor. At a test distance of 3 m, single letters can be displayed from 20/800 to 20/12. A C program on the handheld device runs the Amblyopia Treatment Study visual Acuity testing protocol. Using this method, visual Acuity was tested in both the right and left eyes, and then the testing was repeated in 156 children age 3 to 7 years at four clinical sites. RESULTS: Test-retest reliability was high (r =.92 and 0.95 for and right and left eyes, respectively), with 88% of right eye retests and 94% of left eye retests within 0.1 logarithm of minimal angle of resolution (logMAR) units of the initial test. The 95% confidence interval for an Acuity score was calculated to be the score +/- 0.13 logMAR units. For a change between two Acuity scores, the 95% confidence interval was the difference +/- 0.19 logMAR units. CONCLUSIONS: We have developed a computerized method for measurement of visual Acuity. Automation of the Amblyopia Treatment Study visual Acuity testing protocol is an effective method of testing visual Acuity in children 3 to 7 years of age.
Roy W Beck - One of the best experts on this subject based on the ideXlab platform.
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factors associated with improvement and worsening of visual Acuity 2 years after focal grid photocoagulation for diabetic macular edema
Ophthalmology, 2010Co-Authors: Lloyd Paul Aiello, Roy W Beck, Neil M Bressler, Adam R Glassman, Allison R Edwards, Matthew D Davis, Frederick L Ferris, Kellee M MillerAbstract:Purpose To identify factors associated with the visual Acuity outcome after focal/grid photocoagulation for diabetic macular edema (DME) among eyes randomized to the focal/grid photocoagulation treatment group within the Diabetic Retinopathy Clinical Research Network (DRCR.net) trial comparing triamcinolone with focal/grid laser. Design Multicenter, randomized, clinical trial. Participants Three hundred thirty eyes with DME assigned to the focal/grid photocoagulation group, visual Acuity 20/40 to 20/320, and optical coherence tomography (OCT) central subfield thickness ≥250 microns. Methods Eyes were treated with a protocol-defined photocoagulation technique, which was repeated at 4-month intervals for persistent or recurrent edema. Separate logistic regression models were used to evaluate the associations of demographic, clinical, OCT, and fundus photographic variables with visual Acuity improvement or worsening of ≥10 letters from baseline to 2 years. The association of the initial visual Acuity outcome after treatment with the subsequent visual Acuity course also was evaluated. Main Outcome Measures Visual Acuity measured with the electronic Early Treatment Diabetic Retinopathy Study method. Results Worse baseline visual Acuity was the only factor found to be associated with more frequent visual Acuity improvement ( P P = 0.001) and better baseline visual Acuity ( P = 0.009) were found to be associated with more frequent visual Acuity worsening. Visual Acuity outcomes were similar in eyes with and without prior macular or panretinal photocoagulation. The initial visual Acuity outcome at 4 months was not generally predictive of the subsequent course. Many eyes that worsened ≥10 letters from baseline to 4 months subsequently improved, and many eyes that initially improved, subsequently worsened. Conclusions At this time, focal/grid photocoagulation remains the standard management for DME and these results do not alter this paradigm. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.
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comparison of the amblyopia treatment study hotv and the electronic early treatment of diabetic retinopathy study visual Acuity protocols in amblyopic children aged 5 to 11 years
Journal of Aapos, 2009Co-Authors: Eileen E Birch, Samara F Strauber, Roy W Beck, Jonathan M HolmesAbstract:As part of the long-term follow-up of amblyopic children who were enrolled in the Amblyopia Treatment Study, we tested visual Acuity in both eyes of 142 patients by using 2 established visual Acuity protocols, the Amblyopia Treatment Study HOTV (ATS HOTV) visual Acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, at one of the annual visits. Mean age at the time of testing was 9.0 years (range, 5.6-11.9 years). The ATS-HOTV protocol resulted in a slight mean overestimate of visual Acuity relative to the E-ETDRS protocol (0.68 lines for amblyopic eyes; 0.25 lines for fellow eyes). The overestimation occurred primarily when the E-ETDRS visual Acuity was poorer than 0.3 logMAR. ATS-HOTV Acuity also underestimated interocular visual Acuity differences by 0.42 lines. When one uses the ATS-HOTV protocol, it may be wise to exercise caution when interpreting "near-normal" visual Acuity or interocular differences as "within normal" because the ATS-HOTV method may have a slight bias toward better performance of amblyopic eyes than E-ETDRS.
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relationship between optical coherence tomography measured central retinal thickness and visual Acuity in diabetic macular edema
Ophthalmology, 2007Co-Authors: David J Browning, Roy W Beck, Ronald P Danis, Neil M Bressler, Adam R Glassman, Lloyd Paul Aiello, David M Brown, Donald S Fong, James L Kinyoun, Quan Dong NguyenAbstract:Objective To compare optical coherence tomography (OCT)-measured retinal thickness and visual Acuity in eyes with diabetic macular edema (DME) both before and after macular laser photocoagulation. Design Cross-sectional and longitudinal study. Participants Two hundred ten patients (251 eyes) with DME enrolled in a randomized clinical trial of laser techniques. Methods Retinal thickness was measured with OCT and visual Acuity was measured with the electronic Early Treatment of Diabetic Retinopathy procedure. Main outcome measures Optical coherence tomography-measured center point thickness and visual Acuity. Results The correlation coefficients for visual Acuity versus OCT center point thickness were 0.52 at baseline and 0.49, 0.36, and 0.38 at 3.5, 8, and 12 months after laser photocoagulation. The slope of the best fit line to the baseline data was approximately 4.4 letters (95% confidence interval, 3.5-5.3) of better of visual Acuity for every 100-mum decrease in center point thickness at baseline with no important difference at follow-up visits. Approximately one third of the variation in visual Acuity could be predicted by a linear regression model that incorporated OCT center point thickness, age, hemoglobin A1C, and severity of fluorescein leakage. The correlation between change in visual Acuity and change in OCT center point thickening 3.5 months after laser treatment was 0.44, with no important difference at the other follow-up times. A subset of eyes showed paradoxical improvements in visual Acuity with increased center point thickening (7%-17% at the 3 time points) or paradoxical worsening of visual Acuity with a decrease in center point thickening (18%-26% at the 3 time points). Conclusions There is modest correlation between OCT-measured center point thickness and visual Acuity, and modest correlation of changes in retinal thickening and visual Acuity after focal laser treatment for DME. However, a wide range of visual Acuity may be observed for a given degree of retinal edema. Thus, although OCT measurements of retinal thickness represent an important tool in clinical evaluation, they cannot substitute reliably as a surrogate for visual Acuity at a given point in time. This study does not address whether short-term changes on OCT are predictive of long-term effects on visual Acuity.
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computerized method of visual Acuity testing adaptation of the amblyopia treatment study visual Acuity testing protocol
American Journal of Ophthalmology, 2001Co-Authors: Pamela S Moke, Andrew Turpin, Michael X Repka, Raymond T Kraker, Roy W Beck, Eileen E Birch, Jonathan M Holmes, Richard W Hertle, Joseph M. Miller, Chris A JohnsonAbstract:PURPOSE: To report a computerized method for determining visual Acuity in children using the Amblyopia Treatment Study visual Acuity testing protocol. METHODS: A computerized visual Acuity tester was developed that uses a programmed handheld device that uses the Palm operating system (Palm, Inc, Santa Clara, California). The handheld device communicates with a personal computer running a Linux operating system and 17-inch monitor. At a test distance of 3 m, single letters can be displayed from 20/800 to 20/12. A C program on the handheld device runs the Amblyopia Treatment Study visual Acuity testing protocol. Using this method, visual Acuity was tested in both the right and left eyes, and then the testing was repeated in 156 children age 3 to 7 years at four clinical sites. RESULTS: Test-retest reliability was high (r =.92 and 0.95 for and right and left eyes, respectively), with 88% of right eye retests and 94% of left eye retests within 0.1 logarithm of minimal angle of resolution (logMAR) units of the initial test. The 95% confidence interval for an Acuity score was calculated to be the score +/- 0.13 logMAR units. For a change between two Acuity scores, the 95% confidence interval was the difference +/- 0.19 logMAR units. CONCLUSIONS: We have developed a computerized method for measurement of visual Acuity. Automation of the Amblyopia Treatment Study visual Acuity testing protocol is an effective method of testing visual Acuity in children 3 to 7 years of age.
Michael Bach - One of the best experts on this subject based on the ideXlab platform.
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habitual higher order aberrations affect landolt but not vernier Acuity
Journal of Vision, 2019Co-Authors: J L Reiniger, Michael Bach, Anne C Lobecke, Ramkumar Sabesan, Frenne Verbakel, John De Brabander, Frank G Holz, Tos T J M Berendschot, Wolf M HarmeningAbstract:To assess whether the eye's optical imperfections are relevant for hyperacute vision, we measured ocular wave aberrations, visual hyperAcuity, and Acuity thresholds in 31 eyes of young adults. Although there was a significant positive correlation between the subjects' performance in Vernier- and Landolt-optotype Acuity tasks, we found clear differences in how far both Acuity measures correlate with the eyes' optics. Landolt Acuity thresholds were significantly better in eyes with low higher order aberrations and high visual Strehl ratios (r2 = 0.22, p = 0.009), and significantly positively correlated with axial length (r2 = 0.15, p = 0.03). A retinal image quality metric, calculated as twodimensional correlation between perfect and actual retinal image, was also correlated with Landolt Acuity thresholds (r2 = 0.27, p = 0.003). No such correlations were found with Vernier Acuity performance (r2, 0.03, p > 0.3). Based on these results, hyperAcuity thresholds are, contrary to resolution Acuity, not affected by higher order aberrations of the eye.
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resolution Acuity versus recognition Acuity with landolt style optotypes
Graefes Archive for Clinical and Experimental Ophthalmology, 2013Co-Authors: Sven P. Heinrich, Michael BachAbstract:Background International standards define Acuity as the reciprocal of the threshold gap size of a Landolt C optotype. However, the literature is inconsistent as to what type of Acuity is measured with Landolt Cs. The present study addresses this question more directly than previous studies by quantifying the effect of an inherent luminance artifact in Landolt-style optotypes.
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the freiburg visual Acuity test automatic measurement of visual Acuity
Optometry and Vision Science, 1996Co-Authors: Michael BachAbstract:ABSTRACTThe Freiburg Visual Acuity test is an automated procedure for self-administered measurement of visual Acuity. Landolt-Cs are presented on a monitor in one of eight orientations. The subject presses one of eight buttons, which are spatially arranged on a response box according to the eight po
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the freiburg visual Acuity test automatic measurement of visual Acuity
Optometry and Vision Science, 1996Co-Authors: Michael BachAbstract:The Freiburg Visual Acuity test is an automated procedure for self-administered measurement of visual Acuity. Landolt-Cs are presented on a monitor in one of eight orientations. The subject presses one of eight buttons, which are spatially arranged on a response box according to the eight possible positions of the Landolt-Cs' gap. To estimate the Acuity threshold, a best PEST (best Parameter Estimation by Sequential Testing) procedure is used in which a psychometric function having a constant slope on a logarithmic Acuity scale is assumed. Measurement terminates after a fixed number of trials. With computer monitors, pixel-discreteness artifacts limit the presentation of small stimuli. By using anti-aliasing, i.e., smoothing of contours by multiple gray levels, the spatial resolution was improved by a factor of four. Thus, even the shape of small Landolt-Cs with oblique gaps is adequate and visual acuities from 5/80 (0.06) up to 5/1.4 (3.6) can be tested at a distance of 5 m.
Chris A Johnson - One of the best experts on this subject based on the ideXlab platform.
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computerized method of visual Acuity testing adaptation of the amblyopia treatment study visual Acuity testing protocol
American Journal of Ophthalmology, 2001Co-Authors: Pamela S Moke, Andrew Turpin, Michael X Repka, Raymond T Kraker, Roy W Beck, Eileen E Birch, Jonathan M Holmes, Richard W Hertle, Joseph M. Miller, Chris A JohnsonAbstract:PURPOSE: To report a computerized method for determining visual Acuity in children using the Amblyopia Treatment Study visual Acuity testing protocol. METHODS: A computerized visual Acuity tester was developed that uses a programmed handheld device that uses the Palm operating system (Palm, Inc, Santa Clara, California). The handheld device communicates with a personal computer running a Linux operating system and 17-inch monitor. At a test distance of 3 m, single letters can be displayed from 20/800 to 20/12. A C program on the handheld device runs the Amblyopia Treatment Study visual Acuity testing protocol. Using this method, visual Acuity was tested in both the right and left eyes, and then the testing was repeated in 156 children age 3 to 7 years at four clinical sites. RESULTS: Test-retest reliability was high (r =.92 and 0.95 for and right and left eyes, respectively), with 88% of right eye retests and 94% of left eye retests within 0.1 logarithm of minimal angle of resolution (logMAR) units of the initial test. The 95% confidence interval for an Acuity score was calculated to be the score +/- 0.13 logMAR units. For a change between two Acuity scores, the 95% confidence interval was the difference +/- 0.19 logMAR units. CONCLUSIONS: We have developed a computerized method for measurement of visual Acuity. Automation of the Amblyopia Treatment Study visual Acuity testing protocol is an effective method of testing visual Acuity in children 3 to 7 years of age.
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effects of luminance contrast and blur on visual Acuity
Ophthalmic Literature, 1996Co-Authors: Chris A Johnson, Evanne J CassonAbstract:Although previous investigations have reported that changes in background luminance, stimulus contrast, and dioptric blur can each affect visual Acuity independently, it has not been shown how these three variables interact to influence visual Acuity. This is a particularly important issue if one is interested in predicting how individuals with different refractive characteristics will be able to perform Acuity-based tasks in degraded visual environments with low background lighting and contrast levels. To investigate these relations, we conducted a series of experiments in which measurements of visual Acuity were obtained for four subjects using Landolt C targets of varying contrast at several background luminances for levels of blur between 0 and 8 diopters (D). Our results show that visual Acuity is significantly affected by all three factors, and that their effects are essentially additive. At all luminance and contrast levels, the reduction in visual Acuity is greatest for dioptric blur up to 2.0 D, with a more gradual reduction in visual Acuity for dioptric blur of greater than 2.0 D. At all blur and luminance levels, visual Acuity decreases gradually for contrast levels down to 20%, and decreases sharply for lower contrast levels. Over the range of background luminances we tested (75.0 to 0.075 cd/m2), visual Acuity decreases linearly with reductions in luminance. The additive effects of dioptric blur, contrast, and luminance provide a basis for predicting visual Acuity-related task performance for individuals in different visual environments. For example, an individual with 6/6 (20/20) visual Acuity under high luminance-high contrast conditions will fall to 6/18 (20/60) Acuity for low luminance conditions and 6/30 (20/100) for low luminance-low contrast conditions. Similarly, an individual with an uncorrected visual Acuity of 6/30 (20/100) under optimal conditions will fall to approximately 6/120 (20/400) under low luminance conditions and 6/240 (20/800) under low luminance-low contrast conditions.
E. Christopher Kirk - One of the best experts on this subject based on the ideXlab platform.
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Visual Acuity in the cathemeral strepsirrhine Eulemur macaco flavifrons.
American Journal of Primatology, 2009Co-Authors: Carrie C. Veilleux, E. Christopher KirkAbstract:Studies of visual Acuity in primates have shown that diurnal haplorhines have higher Acuity (30–75 cycles per degree (c/deg)) than most other mammals. However, relatively little is known about visual Acuity in non-haplorhine primates, and published estimates are only available for four strepsirrhine genera (Microcebus, Otolemur, Galago, and Lemur). We present here the first measurements of visual Acuity in a cathemeral strepsirrhine species, the blue-eyed black lemur (Eulemur macaco flavifrons). Acuity in two subjects, a 3-year-old male and a 16-year-old female, was assessed behaviorally using a two-alternative forced choice discrimination task. Visual stimuli consisted of high contrast square wave gratings of seven spatial frequencies. Acuity threshold was determined using a 70% correct response criterion. Results indicate a maximum visual Acuity of 5.1 c/deg for the female (1718 trials) and 3.8 c/deg for the male (846 trials). These values for E. macaco are slightly lower than those reported for diurnal Lemur catta, and are generally comparable to those reported for nocturnal Microcebus murinus and Otolemur crassicaudatus. To examine ecological sources of variation in primate visual Acuity, we also calculated maximum theoretical Acuity for Cheirogaleus medius (2.8 c/deg) and Tarsius syrichta (8.9 c/deg) using published data on retinal ganglion cell density and eye morphology. These data suggest that visual Acuity in primates may be influenced by activity pattern, diet, and phylogenetic history. In particular, the relatively high Acuity of T. syrichta and Galago senegalensis suggests that visual predation may be an important selective factor favoring high visual Acuity in primates. Am. J. Primatol. 71:343–352, 2009. © 2009 Wiley-Liss, Inc.