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Pupil Diameter (pupil + diameter)
Selected AbstractsA non-invasive method for studying an index of pupil diameter and visual performance in the rhesus monkeyJOURNAL OF MEDICAL PRIMATOLOGY, Issue 2 2006Sarah J. Fairhall Abstract Background, A non-invasive model has been developed to estimate gaze direction and relative pupil diameter, in minimally restrained rhesus monkeys, to investigate the effects of low doses of ocularly administered cholinergic compounds on visual performance. Methods, Animals were trained to co-operate with a novel device, which enabled eye movements to be recorded using modified human eye-tracking equipment, and to perform a task which determined visual threshold contrast. Responses were made by gaze transfer under twilight conditions. 4% w/v pilocarpine nitrate was studied to demonstrate the suitability of the model. Results, Pilocarpine induced marked miosis for >3 h which was accompanied by a decrement in task performance. Conclusions, The method obviates the need for invasive surgery and, as the position of point of gaze can be approximately defined, the approach may have utility in other areas of research involving non-human primates. [source] Operational implications of varying ambient light levels and time-of-day effects on saccadic velocity and pupillary light reflexOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2007Minzhong Yu Abstract Changes in maximal saccadic velocity (SV), initial pupil diameter (IPD), constriction latency (CL) and constriction amplitude (CA) determined by the pupillary light reflex have been found to be sensitive indicators of impairment as a result of drugs, sleepiness, and/or fatigue. Ambient illuminance and time of day are controlled when these indices are applied as repeated measures in fitness-for-duty determinations. The application of oculometrics in unrestricted operational environments, where ambient illuminance and time-of-day testing are not constant, requires understanding of, and potential compensation for, the effects of, and interactions among, these multiple uncontrolled variables. SV, IPD, CL, and CA were evaluated in the morning and evening on two consecutive days following adequate nightly sleep under one baseline ambient illuminance and seven test ambient illuminances. Sixteen healthy volunteers (21,38 years, eight females/eight males) participated. Within and across days, SV was unaffected by decreasing ambient light or time-of-day effects. With the increase of ambient light from 670 to 3300 lx, CL decreased by 1%, while IPD and CA decreased by 17% and 20%, respectively. IPD increased with time of day by 1,10% (IPD was smaller in the morning). The results show that SV and CL are essentially resistant to changes in ambient light and time-of-day effects, simplifying their application in uncontrolled operational environments. [source] Normal values and standard deviations for pupil diameter and interpupillary distance in subjects aged 1 month to 19 yearsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2002Colleen MacLachlan Normal values of pupil diameters and interpupillary distances (PDs) were measured in a population of 1311 subjects (in 4294 visits) ranging from 1 month of age to slightly over 19 years of age. Subjects in this study were recruited from birth announcements in a local newspaper for a developmental vision project. Pupil sizes were measured photographically when the corneas were illuminated by 15.9 ± 0.5 lux ambient illumination (i.e. under mesopic conditions). Interpupillary distance was measured with an interocular distance rule while the subject fixated an object at 0.66 m distance. These PD measurements were corrected for systematic measurement errors and to an infinite viewing distance using radii of ocular rotation based on age-dependent axial lengths. Means and S.D. were calculated for age, pupil diameter and PD for each 1-year group of male and female subjects. The second order regression equation for average pupil size as a function of age was determined: [males pupil diameter (in mm)=5.83 + 0.181*age in years , 0053*age in years2, r2=0.897; female pupil diameter=5.40 + 0.285*age in years , 0.0109*age in years2, r2=0.945]. The difference between male and female pupil sizes (mean male , female=0.13 mm) was marginally not significant (p < 0.054). The average corrected PDs as a function of age were found to approximate another second-order regression equation: (males PD=43.36 + 1.663*age in years , 0.034*age in years2, r2=0.986; females PD=41.76 + 1.891*age in years , 0.052*age in years2, r2=0.986). Male PD was wider than female PD by an average of 1.58 mm (p < 0.0003). As expected, the results of this study were similar to a preliminary investigation conducted by Thunyalukul et al. [Invest. Ophthalmol. Vis. Sci.37 (1996) S731] on a portion of the present data set, and also very similar to data from another study of comparable racial composition using a different measurement method [Pryor, Pediatrics44 (1969) 973]. It was concluded that pupil diameter and PD increase more gradually than axial length of the eye in the first few years of life. The normal values and S.D. for both pupil size and PD determined in this study have important clinical implications as well as applications in the optical industry. [source] Accommodation microfluctuations and pupil size during sustained viewing of visual display terminalsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2000L.S. Gray Summary Accommodation microfluctuations comprise two dominant frequencies; a low frequency component (LFC0.6 Hz) and a high frequency component (1.0 Hz Effects of incentive on working memory capacity: Behavioral and pupillometric dataPSYCHOPHYSIOLOGY, Issue 1 2008Richard P. Heitz Abstract We evaluated the hypothesis that individual differences in working memory capacity are explained by variation in mental effort, persons with low capacity exerting less effort than persons with high capacity. Groups previously rated high and low in working memory capacity performed the reading span task under three levels of incentive. The effort hypothesis holds that low span subjects exert less effort during task performance than do high spans. Subjects' pupil sizes were recorded online during task performance as a measure of mental effort. Both recall performance and pupil diameter were found to be increased under incentives, but were additive with span (incentives increased performance and pupil diameter equivalently for both span groups). Contrary to the effort hypothesis, task-evoked pupillary responses indicated that if anything, low span subjects exert more effort than do high spans. [source] Comparison of clozapine and haloperidol on some autonomic and psychomotor functions, and on serum prolactin concentration, in healthy subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 3 2001J. L. Pretorius Aims To compare the autonomic, neuroendocrine and psychomotor effects of single doses of the ,atypical' antipsychotic clozapine and the ,classical' antipsychotic haloperidol, in healthy male volunteers. Methods Clozapine (50 mg), haloperidol (3 mg) and placebo were administered to 12 healthy male volunteers at weekly intervals, according to a balanced double-blind design. Resting pupil diameter, salivary output, heart rate, blood pressure, plasma prolactin concentration, critical flicker fusion frequency and subjective ,alertness', ,contentedness' and ,anxiety' were measured at baseline and 2, 3, 4 and 5 h after drug ingestion. Data were analysed by analysis of variance with individual comparisons (Dunnett's test) with a significance criterion of P < 0.05. Results Significant treatment effects (difference from placebo [mean, 95% CI] 5 h after drug ingestion) were as follows: clozapine reduced pupil diameter (mm; ,3.02 [,3.56, ,2.47]), salivary output (g; ,0.34 [,0.60, ,0.08]), mean arterial blood pressure (mm Hg; ,8.7 [,14.3, ,3.1]), critical flicker fusion frequency (Hz; ,3.26 [,3.94, ,2.58]), and subjectively-rated ,alertness' (mm; ,20.94 [,29.21, ,12.67]) and ,contentedness' (mm; ,12.98 [,17.90, ,8.06]), whereas haloperidol increased prolactin concentration (mU l,1; 301.3 [196.7, 405.8]) and caused small reductions in pupil diameter (mm; ,0.68 [,1.23, ,0.14]), mean arterial blood pressure (mm Hg; ,7.0 [,12.6, ,1.4]) and critical flicker fusion frequency (Hz; ,1.15 [,1.83, ,0.47]). Conclusions The effects of the antipsychotics are in agreement with their receptor binding profiles: ,1 -adrenoceptor blockade by clozapine may contribute to reductions in pupil diameter, salivation, mean arterial blood pressure and sedation, and muscarinic cholinoceptor blockade by the drug may underlie the reduction in salivation. Conversely, D2 dopamine receptor blockade by haloperidol is likely to be responsible for the increase in prolactin secretion evoked by the drug. [source] 3424: Posterior capsule opacification assessment and factors that influence visual quality after posterior capsulotomyACTA OPHTHALMOLOGICA, Issue 2010R MICHAEL Purpose To study the correlation between posterior capsule opacification (PCO) and intraocular straylight and visual acuity. Methods We measured visual acuity (VA) (logMAR) and intraocular straylight (C-Quant straylight parameter log[s]) under photopic conditions before and 2 weeks after YAG capsulotomy in 41 patients (53 eyes) from the Centro de Oftalmología Barraquer in Barcelona and the University Eye Clinic, Paracelsus Medical University in Salzburg. Photopic pupil diameter was also measured. To document the level of opacification, pupils were dilated, and photographs were taken with a slit lamp, using retroillumination and the reflected light of a wide slit beam at an angle of 45º. PCO was subjectively graded on a scale of 0 to 10 and using the POCOman system. A multiple regression analysis was performed to evaluate factors that influence straylight after capsulotomy. Results Straylight correlated well with retroillumination and reflected-light PCO scores, whereas VA only correlated with retroillumination. Both VA and straylight improved after capsulotomy. Straylight values varied widely after capsulotomy. Multiple regression analysis showed that older age, large ocular axial length, hydrophobic acrylic intraocular lenses (IOLs), and small capsulotomies are factors that increased intraocular straylight. Conclusion Intraocular straylight is a useful tool in the assessment of PCO. It correlates well with PCO severity scoring methods. When performing a posterior capsulotomy, factors such as age, IOL material, axial length, and capsulotomy size must be taken into consideration, as they influence intraocular straylight. [source] Optical aberration measurements in dog and cat eyes: interest & limitACTA OPHTHALMOLOGICA, Issue 2008SG ROSOLEN Purpose To measure the ocular optical aberrations in dog and cat using a wavefront aberrometer based on Hartmann-Shack technology. Methods Two dogs and one cat were sedated (Medetomidine, 0.1 mg/kg) and their right eye (RE) pupils were artificially dilated (tropicamide). Wavefront aberrations were measured using an irx3 aberrometer (Imagine Eyes, Orsay, France). Prior to each measurement, the eye was aligned with the instrument optical axis by centering both the eye pupil and Purkinje images. The Hartmann-Shack spot images were produced by an array of 1024 microlenses that defined a 7.2x7.2 mm square area in the pupil plane. In preliminary tests, spot image histograms were optimized by adjusting the sensor acquisition time. Wavefront aberrations were then repeatedly measured 10 times in each animal's RE. Spherical defocus, astigmatism and Zernike coefficients up to the 8th order were finally analyzed. Results The optimal acquisition time was 10 ms for all animals, instead of 33 ms when measuring human eyes. Refractive errors could be analyzed in a 6 mm pupil diameter in all cases. The dilated pupil often exceed the sensor area. The average refractive errors in dog #1, dog #2 and the cat were +2.9D(-2.0D)111°;-0.8D(-0.8D)126° and +3.3D(-2.1D)98°, respectively while their Root Mean Square (RMS) higher-order aberrations amounted to 1.9, 1.1, and 2.1 µm RMS respectively. Standard deviation in sphere and cylinder was 1.0D in the cat and less than 0.5D in both dogs. Standard deviation in the higher-order RMS was 0.8 µm in the cat and less than 0.5 µm in both dogs. The observation of individual data revealed that a significant part of this variability was due to blink-related changes in aberrations. Conclusion Ocular optical aberrations can be easily measured in dog and cat using a Hartmann-Shack aberrometer with reduced image acquisition time. The tested animals had relatively large higher-order wavefront aberrations when compared to date measured in healthy human eyes. Measurement reproducibility was notably affected by tear layer effects. This variability could probably be reduced using a larger sensor area, specific head contention device and artificial tears. This new diagnostic technique is easily feasible without any use of anaesthesia and provides less variability and more detailed information than skiascopy. Wavefront aberrometry could be useful in both research and clinical applications. [source] Effects of higher-order wavefront aberrations on the eye's depth of focusACTA OPHTHALMOLOGICA, Issue 2008N CHATEAU Purpose To evaluate the impact of higher order aberrations (HOA), defined by individual Zernike polynomial coefficients, on the eye's depth of focus using an adaptive optics (AO) system. Methods A crx1 AO visual simulator (Imagine Eyes, France) was used to introduce different amounts of individual 3rd and 4th order HOA in 10 healthy eyes. These HOA included coma (Z(3,-1)) and trefoil (Z(3,-3)) at magnitudes of +/-0.3 µm, and spherical aberration (SA) (Z(4,0)) at magnitudes of +/-0.3,+/-0.6 and +/-0.9 µm through a fixed 6-mm pupil diameter. A through-focus response (TFR) curve was assessed by recording the percentage of optotype letters of fixed 20/50 size that the subject could identify while these letters were presented at various target distances. Testing was performed under cycloplegia. For each applied HOA, the subject's depth of focus (DoF) and center of focus (CoF) were computed as, respectively, the half-maximum width and the midpoint of the TFR curve. Results The introduction of SA resulted in linearly shifting the CoF by 1.3 D for each 0.5 µm of wavefront. The shift was hyperopic with positive SA, myopic with negative SA. The simulation of either positive or negative SA also had the effect of enhancing the DoF, up to a maximum increase of 2 D with 0.6 µm of SA. The enhancement became smaller when the SA was further increased. Trefoil and coma appeared to neither shift the CoF nor significantly modify the DoF. Conclusion AO technology allowed us to selectively test the visual impact of several HOA on the DoF. The introduction of SA significantly shifted and expanded the subjects' overall DoF. This technique could help in designing optimal corrections for presbyopia and allowing patients to preview refractive surgery outcomes. Commercial interest [source] Visual outcome and corneal aberrometry after implantation of intracorneal ring segments (INTACS) for keratoconusACTA OPHTHALMOLOGICA, Issue 2007J HERNANDEZ VERDEJO Purpose: To analyze corneal aberrometry and visual outcome after implantation of intracorneal ring segments (INTACS) in keratoconus patients. Methods: Corneal aberration was measured in 15 keratoconus eyes pre and post implantation of INTACS. Root Mean Square values (RMS), (Total, RMS for corneal astigmatism and RMS for coma) where recorded for 5, 6 and 7 pupil diameters, and where divided into two groups due to their previous levels of coma and total RMS. Comatic aberration was divided in vertical (Z3-1) an horizontal (Z3+1) Zernicke Coeficcients. All data was recorded pre-op and three months after surgery. Best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), spherical equivalent and astigmatism where also analyzed. Results: We found statistically significant decrease in spherical equivalent (p<0,01) and increase of UCVA (p<0,01). Significant increase (p=0,04) in coma and total RMS in patients with lower previous values for 5 and 6mm and significant decrease in patients with higher previous values for 7mm (p=0,03) Conclusions: INTACS implantation for keratoconus reduces the mean spherical refractive error, increases UCVA and improves keratoconus aberrations for 7mm pupil diameter in patients with previous high levels of coma and total RMS. [source] Aberration and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens eyesCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 4 2007Mingbing Zeng PhD MD Abstract Background:, Higher-order aberrations and contrast sensitivity were evaluated in patients who underwent phacoemulsification cataract extraction followed by implantation of aspherical, monofocal or multifocal intraocular lens (IOL) replacements. Methods:, In this comparative trial, 124 patients with an average age of 66.8 ± 5.2 years and their 124 eyes were randomly divided into three surgical implantation groups to receive one of three types of IOLs in replacement of cataract lenses. The patients of group 1 were given an aspherical IOL Z9001 (AMO, Santa Ana, CA, USA) replacement, and group 2 was implanted a monofocal IOL SA60AT (Alcon, Fort Worth, TX, USA) and group 3 the multifocal IOL SA40N (AMO). Post-surgical best-corrected visual acuity, corneal aberrations, total ocular aberrations, pupil diameters, capsulorhexsis sizes and contrast sensitivity were measured and compared. Results:, There was no statistical difference for mean best-corrected visual acuity, pupil diameter, curvilinear capsulorhexis size and corneal aberration among the three groups. For the spherical aberration, fourth-order higher-order aberration and total ocular higher-order aberration, the SA40N group was higher than the SA60AT group and the SA60AT group was higher than the Z9001 group, and the differences between the three groups were statistically significant for these measurements. Contrast sensitivity was higher for the Z9001 group than the SA60AT group and the SA60AT group was higher than the SA40N group, and the difference was statistically significant in all the spatial frequencies of 3, 6, 12 and 18. Conclusions:, Although the multifocal IOL can provide near vision, it can increase higher-order aberration and negatively influence contrast sensitivity. However, the aspherical IOL can reduce aberration and improve contrast sensitivity as compared with the monofocal IOL. [source] Normal values and standard deviations for pupil diameter and interpupillary distance in subjects aged 1 month to 19 yearsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2002Colleen MacLachlan Normal values of pupil diameters and interpupillary distances (PDs) were measured in a population of 1311 subjects (in 4294 visits) ranging from 1 month of age to slightly over 19 years of age. Subjects in this study were recruited from birth announcements in a local newspaper for a developmental vision project. Pupil sizes were measured photographically when the corneas were illuminated by 15.9 ± 0.5 lux ambient illumination (i.e. under mesopic conditions). Interpupillary distance was measured with an interocular distance rule while the subject fixated an object at 0.66 m distance. These PD measurements were corrected for systematic measurement errors and to an infinite viewing distance using radii of ocular rotation based on age-dependent axial lengths. Means and S.D. were calculated for age, pupil diameter and PD for each 1-year group of male and female subjects. The second order regression equation for average pupil size as a function of age was determined: [males pupil diameter (in mm)=5.83 + 0.181*age in years , 0053*age in years2, r2=0.897; female pupil diameter=5.40 + 0.285*age in years , 0.0109*age in years2, r2=0.945]. The difference between male and female pupil sizes (mean male , female=0.13 mm) was marginally not significant (p < 0.054). The average corrected PDs as a function of age were found to approximate another second-order regression equation: (males PD=43.36 + 1.663*age in years , 0.034*age in years2, r2=0.986; females PD=41.76 + 1.891*age in years , 0.052*age in years2, r2=0.986). Male PD was wider than female PD by an average of 1.58 mm (p < 0.0003). As expected, the results of this study were similar to a preliminary investigation conducted by Thunyalukul et al. [Invest. Ophthalmol. Vis. Sci.37 (1996) S731] on a portion of the present data set, and also very similar to data from another study of comparable racial composition using a different measurement method [Pryor, Pediatrics44 (1969) 973]. It was concluded that pupil diameter and PD increase more gradually than axial length of the eye in the first few years of life. The normal values and S.D. for both pupil size and PD determined in this study have important clinical implications as well as applications in the optical industry. [source] Ocular wavefront analysis and contrast sensitivity in eyes implanted with AcrySof IQ or AcrySof Natural intraocular lensesACTA OPHTHALMOLOGICA, Issue 7 2009Tamer Takmaz Abstract. Purpose:, This study aimed to compare ocular wavefront aberrations for pupil diameters of 4 mm and 6 mm, and contrast sensitivity, in eyes with AcrySof IQ and AcrySof Natural intraocular lenses (IOLs). Methods:, Sixty eyes of 60 patients were enrolled in this prospective randomized study. After phacoemulsification the eyes received either AcrySof IQ SN60WF or AcrySof Natural SN60AT IOLs. One month after surgery, all patients underwent complete ophthalmological examination including corneal topography, wavefront analysis for pupil diameters of 4 mm and 6 mm, and contrast sensitivity measurements with the CSV 1000E instrument under photopic and mesopic conditions with and without glare. Results:, There was no statistically significant difference between groups in age, sex or other preoperative ocular characteristics (p > 0.05). Patients with AcrySof IQ IOLs had higher contrast sensitivity at 6 c.p.d. under photopic conditions, at 6 c.p.d. and 18 c.p.d. under mesopic conditions, and at 6 c.p.d., 12 c.p.d. and 18 c.p.d. under mesopic conditions with glare (p < 0.05). Corneal spherical aberration was 0.273 ± 0.074 ,m in the AcrySof Natural group and 0.294 ± 0.086 ,m in the AcrySof IQ group (p = 0489). Ocular spherical aberration was 0.362 ± 0.141 ,m and 0.069 ± 0.043 ,m (p < 0.001) for 6-mm diameter pupils and 0.143 ± 0.091 ,m and 0.017 ± 0.016 ,m (p < 0.001) for 4-mm diameter pupils, with AcrySof Natural and AcrySof IQ IOLs, respectively. There were no significant differences in other higher-order aberrations between the groups (p > 0.05). Conclusions:, Aspherical AcrySof IQ IOLs significantly reduced spherical aberration for pupil diameters of both 4 mm and 6 mm and also improved contrast sensitivity more than spherical AcrySof Natural IOLs, especially in mesopic conditions. [source] Visual outcome and corneal aberrometry after implantation of intracorneal ring segments (INTACS) for keratoconusACTA OPHTHALMOLOGICA, Issue 2007J HERNANDEZ VERDEJO Purpose: To analyze corneal aberrometry and visual outcome after implantation of intracorneal ring segments (INTACS) in keratoconus patients. Methods: Corneal aberration was measured in 15 keratoconus eyes pre and post implantation of INTACS. Root Mean Square values (RMS), (Total, RMS for corneal astigmatism and RMS for coma) where recorded for 5, 6 and 7 pupil diameters, and where divided into two groups due to their previous levels of coma and total RMS. Comatic aberration was divided in vertical (Z3-1) an horizontal (Z3+1) Zernicke Coeficcients. All data was recorded pre-op and three months after surgery. Best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), spherical equivalent and astigmatism where also analyzed. Results: We found statistically significant decrease in spherical equivalent (p<0,01) and increase of UCVA (p<0,01). Significant increase (p=0,04) in coma and total RMS in patients with lower previous values for 5 and 6mm and significant decrease in patients with higher previous values for 7mm (p=0,03) Conclusions: INTACS implantation for keratoconus reduces the mean spherical refractive error, increases UCVA and improves keratoconus aberrations for 7mm pupil diameter in patients with previous high levels of coma and total RMS. [source] Aberration and contrast sensitivity comparison of aspherical and monofocal and multifocal intraocular lens eyesCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 4 2007Mingbing Zeng PhD MD Abstract Background:, Higher-order aberrations and contrast sensitivity were evaluated in patients who underwent phacoemulsification cataract extraction followed by implantation of aspherical, monofocal or multifocal intraocular lens (IOL) replacements. Methods:, In this comparative trial, 124 patients with an average age of 66.8 ± 5.2 years and their 124 eyes were randomly divided into three surgical implantation groups to receive one of three types of IOLs in replacement of cataract lenses. The patients of group 1 were given an aspherical IOL Z9001 (AMO, Santa Ana, CA, USA) replacement, and group 2 was implanted a monofocal IOL SA60AT (Alcon, Fort Worth, TX, USA) and group 3 the multifocal IOL SA40N (AMO). Post-surgical best-corrected visual acuity, corneal aberrations, total ocular aberrations, pupil diameters, capsulorhexsis sizes and contrast sensitivity were measured and compared. Results:, There was no statistical difference for mean best-corrected visual acuity, pupil diameter, curvilinear capsulorhexis size and corneal aberration among the three groups. For the spherical aberration, fourth-order higher-order aberration and total ocular higher-order aberration, the SA40N group was higher than the SA60AT group and the SA60AT group was higher than the Z9001 group, and the differences between the three groups were statistically significant for these measurements. Contrast sensitivity was higher for the Z9001 group than the SA60AT group and the SA60AT group was higher than the SA40N group, and the difference was statistically significant in all the spatial frequencies of 3, 6, 12 and 18. Conclusions:, Although the multifocal IOL can provide near vision, it can increase higher-order aberration and negatively influence contrast sensitivity. However, the aspherical IOL can reduce aberration and improve contrast sensitivity as compared with the monofocal IOL. [source]
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