Maximum Pupil Dilation Research Articles

Intracameral Anaesthetic Mydriatic Versus Topical Mydriasis in Pediatric Cataract Surgery: A Randomized Control Study

To compare pupil dynamics after using premixed intracameral anesthetic mydriatic combination (ICAM) of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) versus topical mydriatic (TM) drops consisting of tropicamide 0.8%, phenylephrine 5%, and cyclopentolate 0.5% in pediatric cataract surgery. Randomized, masked, fellow eye-controlled trial. Tertiary eye care facility. Children ≤12 years of age with bilateral cataracts planned for surgery. One eye was randomized to receive ICAM and the other eye (control) TM drops. Commercially available ICAM that was injected at the beginning of surgery or TM 3 times at an interval of 30 minutes, 1 hour before the scheduled time of surgery. The other treatment was administered for the second eye cataract surgery. Pupil dynamics at various points of surgery were studied by a masked observer. Sixty-three patients (126 eyes) were randomized to receive ICAM in 1 eye (group 1) or TM drops (group 2). The mean age of the children in the study was 15.7 ± 24.3 months (range 3 months to 5 years). Adequate mydriasis with a single injection was achieved in 93.5% of patients in group 1 and 88.8% of patients in group 2 without additional pharmacotherapy or intervention. The mean pupillary diameter increased from 1.78 mm to 5.1 mm after injection of 1 unit of ICAM and from 1.75 mm to 6.06 mm with TM drops (P < .0001). The maximum pupillary dilation achieved was 6.06 ± 1.17 mm in group 1 and 6.75 ± 1.07 mm in group 2 (P = .004). The average change in pupillary size from injection of drug until the end of surgery was positive in group 1 (0.75 ± 0.98 mm) and negative in group 2 (-0.3348 ± 2.57 mm), ie, there was a relative miosis in group 2 toward the end of surgery (P = .001). Topical drugs achieved a larger maximum pupil size compared with ICAM. However, ICAM provided adequate and stable mydriasis without the need for augmentation compared with topical drops in children undergoing cataract surgery.

Adopting Maximum Pupil Diameter to Detect Subtle Usability Issues of a Smartphone Application, Conflict Solver

With the increasing popularity and unparalleled ubiquity of smartphones, researchers in various fields are designing and developing novel applications for this platform as part of the solution to the challenging problems they face. Usability lies at the core of the user experience of such applications. However, the assessments used are often limited to summative and post-event methods, which can overlook subtle yet impactful issues. Objective and instantaneous measures of cognitive workloads provide a solution to this shortcoming. Our previous research has established the reliability of maximum pupil dilation, measured with Tobii Pro Nano, as a preeminent indicator of cognitive workload surges in mobile application users. In this study, we used this measure to locate user cognitive workload peaks while using Conflict Solver and discovered subtle user interface issues that were not reported in the post-usability interview. A total of 30 participants completed a Conflict Solver usability experiment with two phases. In phase 1, the participants performed two “Add a Term” tasks on the original Conflict Solver, followed by a semi-structured interview about their experience with the application. A few subtle usability issues with a drop-down menu were detected through identifying user cognitive workload peaks. In phase 2, the same participants completed the same tasks on Conflict Solver with a redesigned and extended drop-down menu. The results showed that the new design solved the usability issues, and the participants became more favor the drop-down menu over the input box. In conclusion, including maximum pupil dilation into the usability assessment toolkit would provide a more objective and comprehensive usability assessment of a smartphone application. It can also be used to verify the successfulness of a user interface design solution.

The dynamics of experiencing Gestalt and Aha in cubist art: pupil responses and art evaluations show a complex interplay of task, stimuli content, and time course.

Gestalt perception refers to the cognitive ability to perceive various elements as a unified whole. In our study, we delve deeper into the phenomenon of Gestalt recognition in visual cubist art, a transformative process culminating in what is often described as an Aha moment. This Aha moment signifies a sudden understanding of what is seen, merging seemingly disparate elements into a coherent meaningful picture. The onset of this Aha moment can vary, either appearing almost instantaneously, which is in line with theories of hedonic fluency, or manifesting after a period of time, supporting the concept of delayed but more in-depth meaningful insight. We employed pupillometry to measure cognitive and affective shifts during art interaction, analyzing both maximum pupil dilation and average dilation across the trial. The study consisted of two parts: in the first, 84 participants identified faces in cubist paintings under various conditions, with Aha moments and pupil dilation measured. In part 2, the same 84 participants assessed the artworks through ratings in a no-task free-viewing condition. Results of part 1 indicate a distinctive pattern of pupil dilation, with maximum dilation occurring at both trial onset and end. Longer response times were observed for high-fluent, face-present stimuli, aligning with a delayed but accurate Aha-moment through recognition. Additionally, the time of maximum pupil dilation, rather than average dilation, exhibited significant associations, being later for high-fluent, face-present stimuli and correct detections. In part 2, average, not the time of maximum pupil dilation emerged as the significant factor. Face-stimuli and highly accessible art evoked stronger dilations, also reflecting high clearness and negative valence ratings. The study underscores a complex relationship between the timing of recognition and the Aha moment, suggesting nuanced differences in emotional and cognitive responses during art viewing. Pupil dilation measures offer insight into these processes especially for moments of recognition, though their application in evaluating emotional responses through artwork ratings warrants further exploration.

Predicting zonular strength based on maximum pupillary mydriasis in patients with pseudoexfoliation syndrome

Pseudoexfoliation Syndrome (PXFS) is considered a systemic disorder with significant ocular manifestations ranging from corneal decompensation, non-dilating pupil, zonular weakness, subluxated lens, and glaucoma. PXFS may lead to increased complications during routine cataract surgery. Zonular dialysis is a common complication during or after cataract surgery in such patients. However, not all patients with pseudoexfoliation are at a higher risk. We hypothesize that there is an inverse correlation between the maximum pupillary dilation and the degree of zonular disintegration. Available evidence supporting the hypothesis is discussed. We propose a new clinical classification for predicting the zonular strength based on the maximum pupillary dilation so that it can serve as a guide to identify PXFS patients who are at high risk of complications during or after cataract surgery.

Pupillometry Assessment of Speech Recognition and Listening Experience in Adult Cochlear Implant Patients.

ObjectiveThe aim of the present study was to investigate the pupillary response to word identification in cochlear implant (CI) patients. Authors hypothesized that when task difficulty (i.e., addition of background noise) increased, pupil dilation markers such as the peak dilation or the latency of the peak dilation would increase in CI users, as already observed in normal-hearing and hearing-impaired subjects.MethodsPupillometric measures in 10 CI patients were combined to standard speech recognition scores used to evaluate CI outcomes, namely, speech audiometry in quiet and in noise at +10 dB signal-to-noise ratio (SNR). The main outcome measures of pupillometry were mean pupil dilation, maximal pupil dilation, dilation latency, and mean dilation during return to baseline or retention interval. Subjective hearing quality was evaluated by means of one self-reported fatigue questionnaire, and the Speech, Spatial, and Qualities (SSQ) of Hearing scale.ResultsAll pupil dilation data were transformed to percent change in event-related pupil dilation (ERPD, %). Analyses show that the peak amplitudes for both mean pupil dilation and maximal pupil dilation were higher during the speech-in-noise test. Mean peak dilation was measured at 3.47 ± 2.29% noise vs. 2.19 ± 2.46 in quiet and maximal peak value was detected at 9.17 ± 3.25% in noise vs. 8.72 ± 2.93% in quiet. Concerning the questionnaires, the mean pupil dilation during the retention interval was significantly correlated with the spatial subscale score of the SSQ Hearing scale [r(8) = −0.84, p = 0.0023], and with the global score [r(8) = −0.78, p = 0.0018].ConclusionThe analysis of pupillometric traces, obtained during speech audiometry in quiet and in noise in CI users, provided interesting information about the different processes engaged in this task. Pupillometric measures could be indicative of listening difficulty, phoneme intelligibility, and were correlated with general hearing experience as evaluated by the SSQ of Hearing scale. These preliminary results show that pupillometry constitutes a promising tool to improve objective quantification of CI performance in clinical settings.

Pupillary responses and reaction times index different cognitive processes in a combined Go/Switch incidental learning task

In previous studies we have provided evidence that performance in speeded response tasks with infrequent target stimuli reflects both automatic and controlled cognitive processes, based on differences in reaction time (RT) and task-related brain responses (Cheyne et al. 2012, Isabella et al. 2015). Here we test the hypothesis that such shifts in cognitive control may be influenced by changes in cognitive load related to stimulus predictability, and that these changes can be indexed by task-evoked pupillary responses (TEPR). We manipulated stimulus predictability using fixed stimulus sequences that were unknown to the participants in a Go/Switch task (requiring a switch response on 25% of trials) while monitoring TEPR as a measure of cognitive load in 12 healthy adults. Results showed significant improvement in performance (reduced RT, increased efficiency) for repeated sequences compared to occasional deviant sequences (10% probability) indicating that incidental learning of the predictable sequences facilitated performance. All behavioral measures varied between Switch and Go trials (RT, efficiency), however mean TEPR amplitude (mTEPR) and latency to maximum pupil dilation were particularly sensitive to Go/Switch. Results were consistent with the hypothesis that mTEPR indexes cognitive load, whereas TEPR latency indexes time to response selection, independent from response execution. The present study provides evidence that incidental pattern learning during response inhibition tasks may modulate several cognitive processes including cognitive load, effort, response selection and execution, which can in turn have differential effects on measures of performance. In particular, we demonstrate that reaction time may not be indicative of underlying cognitive load.

Drug-induced mydriasis in infants born at different gestation terms

Background. At the present time, the problem of choice of eye drops to achieve adequate mydriasis with minimal side effects for retinopathy of prematurity screening remains an urgent challenge.&#x0D; Purpose. To estimate the clinical efficacy of combination mydriatic eye drops Fenicamide in infants born at different gestation terms.&#x0D; Materials and methods. Under observation, there were 75 newborns (150 eyes) and babies aged from 1 day to 3 months (average, 38.2 32.2 days). Patients were distributed into 3 groups depending on gestational age: group 1 consisted of 25 full-term infants; group 2 of 25 premature babies, and group 3 of 25 extremely preterm infants. To achieve mydriasis, 1 drop of combination eye drops (5% phenylephrine and 0.8% tropicamide) was instilled. Dynamics of pupil diameter change in each group of patients was registered within 4 hours, and side effects were recorded within 24 hours. The quality of fundus visualization was estimated using a pediatric retinal camera RetCam 3.&#x0D; Results. Maximal pupil dilation (average, 6.5 0.5 mm) was reached to 60 14 min after instillation on average; pupil remained dilated within 1 hour, its diameter became normal in 4 hours. Mydriasis varied from 5.9 mm in extremely premature infants to 7 mm in the full-term newborns (p 0.05), and allowed a full and high quality examination of the fundus in all patients, including the visualization of peripheral zones of the retina for retinopathy of prematurity screening. It was established that drug side effects were absent in 76% (57) of infants, they were present in 24% (18) of infants, mostly as local reaction.&#x0D; Conclusion. Fenicamide eye drops are an effective mydriatic medication, with a convenient instillation regimen, have minimal side effects, and can be recommended for retinopathy of prematurity screening and monitoring.

Changes in intraocular pressure and horizontal pupil diameter during use of topical mydriatics in the canine eye.

The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically normal canine patients (between the ages of 2 and 6 years) of varying breed and sex were used in this study. Animals were randomly divided into four groups of ten and given one drop of tropicamide, atropine, phenylephrine or saline into one eye. IOP and HPD were measured in both eyes every 5 minutes for 60 minutes. Tropicamide increased IOP by 8.8±4.0 mmHg 35 minutes post-treatment compared to pre-treatment (P<0.01) only in treated eye. IOP in the contralateral eye did not increase. With atropine the maximum increase in IOP was 2.6±2.8 mmHg at 20 minutes post treatment in the treated eye (P<0.01). IOP in the contralateral eye did not increase. Phenylephrine increased IOP by 2.3±2.1 mmHg (P<0.05) 10 minutes after treatment. Also in the untreated eye IOP increased by 2.3±2.1 mmHg, 20 minutes post-treatment. Maximum HPD in eyes treated with tropicamide occurred at 55 minutes and with atropine at 60 minutes. There were no HPD changes in the contralateral, untreated eye. Topical 10% phenylephrine showed maximal pupil dilation 60 minutes after treatment, but the HPD of the – untreated eye slightly decreased at 15 minutes, but this change only reached statistical significance at 40 min post- treatment (P<0.05). Normal saline showed no influence on IOP or HPD. The drugs investigated here show a significant increase in IOP after mydriatics.

Assessment of a smartphone-based camera for fundus imaging in animals.

To assess the use of an optical device (D-EYE; Si14 S.p.A.) attached to a modern smartphone (iPhone 5; Apple Inc.) for imaging the fundus in small animals. Five dogs, five cats, and five rabbits with clear media were imaged using a prototype of the D-EYE. The optical device was composed of lenses, polarizing filters, a beam splitter, a diaphragm, and mirrors, attached to a smartphone via a metal shell. Images were obtained 20 min after pupil dilation with topical 0.5% tropicamide in a darkened room, to ensure maximum pupillary dilation. Focus was set to the infinite when the autofocus was overwhelmed. Light intensity was adapted to each animal via the application (minimum light intensity for imaging the tapetal region, maximum light intensity for imaging the nontapetal region). Both still images and video sequences were recorded for each animal. Posterior segment structures were visible in all animals: optic nerve head, tapetum lucidum (when present), nontapetal region, retinal vessels, and choroidal vessels (when the retinal pigment epithelium and the choroidal pigmentation were discreet). Focal light artifacts were common when photographing the tapetum lucidum. Recording videos allowed the visualization of dynamic phenomena. The D-EYE assessed appears to be an easy means of obtaining images of the posterior segment structures.

Comparative study measuring the dilatory effect of a mydriatic device (Mydriasert(®)) versus topical drops.

To compare the mydriatic efficacy of an ophthalmic insert (Mydriasert, MY) versus phenylephrine and tropicamide (PT) eye drops. Two controlled, prospective, randomized, single-blind studies were performed. In the first study, a total of 80 eyes from 40 outpatient-clinic patients were analyzed. PT drops were applied to the right eye, and a MY device was inserted in the left eye for 30min. Time until maximal pupil dilation for each eye was then assessed. In the second study, 80 eyes from 80 patients undergoing cataract surgery were analyzed. Pupil dilation was achieved using either PT drops three-times for one hour prior to surgery (40 patients), or a MY device was inserted one hour prior to surgery (40 patients). In the first study, MY achieved superior mydriasis compared to PT eye drops at 90min (9.04±1.33mm vs 8.78±1.37mm, P=0.012). However MY took longer than PT drops to achieve maximal dilation, and mydriasis was inferior in eyes with MY compared to PT drops at 30min (7.21±1.73mm vs 8.22±1.43mm, P<0.001), the two groups only becoming similar by 60min (8.85±1.44mm vs 8.71±1.27mm, P=0.236). In the second study, both MY and PT achieved similar levels of mydriasis at the beginning of surgery (8.75±0.76mm with MY vs 8.77±0.63mm with PT), and also at the end of surgery (7.96±1.06mm with MY vs 8.32±0.72mm with PT), with no significant difference between groups (P=0.08). MY was well tolerated and cardiovascular effects were not influenced by dilation method. MY could be a safe and efficacious alternative for mydriasis. The mydriatic effect of MY is as good as conventional PT eye drops after 60min, and is superior after 90min. MY also maintains good pupil dilation during cataract surgery.

How to Become a Mentalist: Reading Decisions from a Competitor’s Pupil Can Be Achieved without Training but Requires Instruction

Pupil dilation is implicated as a marker of decision-making as well as of cognitive and emotional processes. Here we tested whether individuals can exploit another’s pupil to their advantage. We first recorded the eyes of 3 "opponents", while they were playing a modified version of the "rock-paper-scissors" childhood game. The recorded videos served as stimuli to a second set of participants. These "players" played rock-paper-scissors against the pre-recorded opponents in a variety of conditions. When players just observed the opponents’ eyes without specific instruction their probability of winning was at chance. When informed that the time of maximum pupil dilation was indicative of the opponents’ choice, however, players raised their winning probability significantly above chance. When just watching the reconstructed area of the pupil against a gray background, players achieved similar performance, showing that players indeed exploited the pupil, rather than other facial cues. Since maximum pupil dilation was correct about the opponents’ decision only in 60% of trials (chance 33%), we finally tested whether increasing this validity to 100% would allow spontaneous learning. Indeed, when players were given no information, but the pupil was informative about the opponent’s response in all trials, players performed significantly above chance on average and half (5/10) reached significance at an individual level. Together these results suggest that people can in principle use the pupil to detect cognitive decisions in another individual, but that most people have neither explicit knowledge of the pupil’s utility nor have they learnt to use it despite a lifetime of exposure.

Efficacy of tropicamide, homatropine, cyclopentolate, atropine and hyoscine as mydriatics in Angora goats

AIM: To document the efficacy of five commercially available mydriatics for their potential for diagnostic and therapeutic use in Angora goats. METHODS: Over 8 weeks, the mydriatic effects of 1% tropicamide, 2% homatropine, 1% cyclopentolate, 1% atropine and 0.25% hyoscine were evaluated. Given as block treatments, drugs were applied randomly to one eye of 10 Angora goats, and the contralateral eye served as a control. Vertical and horizontal pupil diameters were measured to document onset ofeffect, time to reach a difference of 5 mm in the vertical/horizontal pupil diameter between eyes, time to maximum pupillary dilation, and duration of mydriatic action. RESULTS: Onset of mydriasis for all drugs occurred within 15 minutes. Time to reach a difference of 5 mm in the vertical pupil diameter between eyes was shortest for 1% tropicamide and 0.25% hyoscine (0.5 h), then 2% homatropine and 1% atropine (0.75 h), and longest for 1% cyclopentolate (1.5 h). The maximum vertical pupillary dilation occurred earliest with 1% tropicamide and 1% atropine (2 h), followed by 0.25% hyoscine (3 h), 2% homatropine (4 h), and latest with 1% cyclopentolate (8 h). The duration of vertical dilation of the pupil was shortest with 1% tropicamide (6 h), then 2% homatropine (12 h), 1% cyclopentolate (12 h), 1% atropine (24 h), and longest for 0.25% hyoscine (96 h). The time to reach maximum horizontal dilation of the pupil in treated eyes was shortest with 1% cyclopentolate (1 h), followed by 1% tropicamide (1.5 h), 0.25% hyoscine (3 h), 2% homatropine (3.5 h), and 1% atropine (4 h). The duration of horizontal pupil dilation was shortest with 1% tropicamide (4.5 h), and longest with 0.25% hyoscine (48 h). CONCLUSION: All five mydriatics induced clinical dilation. Tropicamide (1%) had the shortest duration of effect, but gave incomplete dilation. Good dilation was achieved with 1% cyclopentolate and 2% homatropine, but took too long to reach maximum dilation for routine mydriasis. The largest vertical dilation of the pupil was achieved with 1% atropine and 0.25% hyoscine, but pupils remained dilated for more than 24 h. CLINICAL RELEVANCE: For routine mydriasis in goats, it is recommended that 1% tropicamide be used, though there may be incomplete dilation. For a longer duration of mydriasis, such as in the treatment of anterior uveitis, 1% atropine or 0.25% hyoscine would be the drugs of choice.

Changes in objective refraction after pharmacological pupil dilation

Abstract Purpose To analyze the variation of the objective refraction induced by pharmacological pupillary dilation in a normal population. Methods The objective refraction obtained by an auto‐kerato‐refractometer was analyzed before and after maximum pupillary dilation obtained by 0.5% Tropicamide and 10% Phenylephrine. 200 phakic eyes of 100 patients aged from 15 to 76 years were prospectively included. The refractive data were expressed in a dioptric space by 3 Cartesian coordinates (X, Y, Z). Results After pupil dilation, the mean refraction ranges from ‐0.08(+0.11)×90.2° to +0.41(+0.10)×90.3° this equal to an astigmatic vectorial variation of (+0.03)×89.6°. The spherical equivalent increases significantly (hyperopization of +0.49D: +0.24D vs +0.74D p&lt;0.001) contrary to the mean keratometry (43.48D vs 43.49 p=0.40) and the cylinder (0.64D vs 0.64D p=0.49) which are unchanged. Change in spherical equivalent is correlated with the age (r=‐0.34 p&lt;0.001) but not with the change in keratometry (r=0.06 p=0.20) or the initial spherical equivalent (r=‐0.05 p=0.23). The mean change in axis between both exams is 15.4° for the ocular astigmatism and 12.2° for the corneal astigmatism. The modification in spherical equivalent of both eyes of a patient are not different (p=0.26) and are strongly correlated (r=0.85 p&lt;0.001) contrary to the modification in axis and in cylinder. Conclusion Pharmacological pupil dilation modifies primarily the spherical equivalent without significant modification of keratometry and astigmatism. Finally, hyperopization is probably due to the cycloplegic effect of eye drops.

Effect of intraocular lens asphericity on vertical coma aberration

To analyze the effect of asphericity of intraocular lenses (IOLs) on vertical coma aberration after implantation of spherical, spherically neutral, and aspheric IOLs. Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. This observational study recruited patients from previous prospective randomized fellow-eye controlled studies comparing aspheric and spherical IOLs (3 spherical, 1 spherically neutral, and 2 aspheric IOLs). At postoperative follow-up visits, maximum pupil dilation was achieved and aberrometry was performed using an iTrace aberrometer with a pupil scan size of 5.0 mm. Data on Zernike coefficients Z(3,-1) (vertical coma), Z(3,+1) (horizontal coma), and Z(4,0) (spherical aberration) and on IOL power were extracted. Two hundred eyes of 100 patients were recruited. Ninety-two eyes had a spherical IOL, 32 eyes had a spherically neutral IOL, and 76 eyes had an aspheric IOL. Vertical coma Z(3,-1) and spherical aberration Z(4,0) values were highest with the spherical IOLs and lowest with the aspheric IOLs (P = .0163 and P<.0001, respectively). There was no difference in horizontal coma aberration between the 3 IOL groups. There was no correlation between IOL power and vertical coma aberration (r(2) = 0.0135, P = .1169). Conventional spherical IOLs induced more vertical coma than newer aspheric and spherically neutral IOLs. Vertical coma aberration enhances the depth of focus; thus, newer aspheric and spherically neutral designs of IOLs may negatively affect uncorrected near vision.

New insights into feature and conjunction search: II. Evidence from Alzheimer's disease

Deficits in inefficient visual search task performance in Alzheimer's disease (AD) have been linked both to a general depletion of attentional resources and to a specific difficulty in performing conjunction discriminations. It has been difficult to examine the latter proposal because the uniqueness of conjunction search as compared to other visual search tasks has remained a matter of debate. We explored both these claims by measuring pupil dilation, as a measure of resource application, while patients with AD performed a conjunction search task and two single-feature search tasks of similar difficulty in healthy individuals. Maximum pupil dilation in the AD group was greater during performance of the conjunction than the feature search tasks, although pupil response was indistinguishable for the three tasks in healthy controls. This, together with patients' false positive errors for the conjunction task, indicates an AD-specific deficit impacting upon the ability to combine information on multiple dimensions. In addition, maximum pupil dilation was no less for patients than the control group during task performance, which tends to oppose the concept of general resource depletion in AD. However, eye movement patterns in the patient group indicated that they were less able than controls to use organised strategies to assist with task performance. The data are therefore in keeping with a loss of access to resource-saving strategies, rather than a loss of resources per se, in AD. Moreover they demonstrate an additional processing mechanism in performing conjunction search compared with inefficient single-feature search.

You can see pain in the eye: Pupillometry as an index of pain intensity under different luminance conditions

Pupil dilation is regulated autonomically and it may be a valid measure of pain, but pupillometry for pain intensity recordings has not been evaluated under different luminance conditions. We hypothesized that the pupil response may serve as an objective indicator of pain intensity even if luminance conditions differ which is often the case in experiments with pictures. In 20 healthy females we applied a tonic pressure pain to the fingers (20 s). During pain induction, participants looked at pictures of three different levels of luminance. Pupil dilation was recorded continuously. Immediately after pain onset, there was a significant pupil dilation which reached its maximum about 2 s after pain onset. While this maximum pupil dilation did not differ with pressure intensity, the pupil dilation was larger for the higher pressure intensity in the period from 10 s after pressure onset to pressure offset. Even under different luminance conditions, pupillometry can serve as an objective indicator of pressure pain intensity. Thus, it seems promising to use pupillometry with complex experimental designs combining pain and pictorial stimuli.

Le segment antérieur de l’œil des diabétiques

To study the damage to the anterior segment of the eye during mellitus diabetes. We prospectively studied the anterior segment of the eye in 200 diabetic patients and 200 patients with no history of diabetes (control group). Parameters included the corneal curvature radius, corneal thickness, central corneal sensitivity (Cochet Bonnet esthesiometer), pupil diameter before and after dilation using tropicamide and phenylephrine eye drops, delay for maximal pupil dilation, lens transparency, and intraocular pressure. The damage to the anterior segment was compared in both groups and was correlated with the parameters of diabetes (type, duration, and equilibration), retinopathy grade, and peripheral neuropathy. Corneal geometry (i.e., curvature radius and thickness) and intraocular pressure did not correlate with diabetes. Cataract was significantly influenced by diabetes (p<0.001). The duration needed to obtain pharmacological maximal mydriasis significantly correlated with iris color (rs=0.47, p<0.001), patient age (rs=0.28, p<0.001) and diabetes (rs=0.25, p<0.001). Dilation was significantly longer in the diabetic patient than in those of the control group (36.5 min vs 30.7 min, p<0.001). Corneal sensitivity significantly correlated with age (rs=0.48, p<0.001) and diabetes (rs=0.53, p<0.001). Corneal sensitivity was decreased in the diabetic group (5.42 vs 5.94, p<0.001) and it correlated with retinopathy grade (rs=0.47, p<0.001) and with peripheral neuropathy (rs=0.15, p<0.001). Sensitivity and specificity of hypoesthesia in detecting peripheral neuropathy were 67.4% and 49.4%, respectively. Among the parameters of diabetes, duration of progression showed the strongest correlation with damage to anterior segment (rs > or = 0.25, p<0.001). Diabetes influences lens transparency, pharmacological pupil dilatation and corneal sensitivity. In spite of the unspecific character of the damage and the subjectivity of the measurement, corneal sensitivity is an interesting parameter to take into consideration among diabetic patients.

Diagnosis and management of congenital cataract with preexisting posterior capsule defect

Purpose: To establish and evaluate the diagnostic signs, intraoperative performance, and postoperative outcomes in children with congenital cataract with a preexisting posterior capsule defect (PCD). Setting: Iladevi Cataract & IOL Research Centre, Ahmedabad, India. Methods: This study evaluated 400 consecutive eyes that had congenital cataract surgery, of which 27 (20 children) had a confirmed preexisting PCD. Seven children had bilateral defects. The preoperative diagnostic signs of PCD under maximum pupil dilation included well-demarcated, thick defect margins; white dots on the posterior capsule; and white dots in the anterior vitreous that moved with the degenerated vitreous like a fish tail (fish-tail sign). Hydrodissection was not attempted. Bimanual irrigation/aspiration and 2-port anterior vitrectomy were performed. The mean follow-up was 17.9 months ± 16.96 (SD). Results: The mean age of the 16 boys and 4 girls with a PCD was 21.98 ± 33.33 months. Nineteen eyes (70.3%) had total white mature cataract. In 7 eyes (25.92%), the preexisting PCD was converted into a posterior capsulorhexis. Twenty eyes (74.07%) had an AcrySof MA30BA intraocular lens (IOL) implanted in the bag and 4 eyes (14.81%), in the sulcus. Three eyes (11.11%) were left aphakic. The visual axis remained clear in all eyes, and the IOL was well centered in 24 eyes (88.88%). Conclusion: Establishing the diagnostic signs of PCD with the eye fully dilated and carefully planning the surgery produced satisfactory technical and visual outcomes.

Speed of capsular bend formation at the optic edge of acrylic, silicone, and poly(methyl methacrylate) lenses

Purpose To evaluate how and how fast a capsular bend is created clinically at the optic edge of an intraocular lens (IOL) after cataract surgery. Setting Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. Methods Capsular bend formation was observed by slitlamp after maximum pupil dilation in 45 eyes of 45 patients with senile cataract. Fifteen eyes each received an AcrySof® MA60BM acrylic (Alcon), PhacoFlex II® SI-40NB silicone (Allergan), or UV26T poly(methyl methacrylate) (PMMA) (Menicon) IOL. Patients were evaluated prospectively at 1 day and 1, 2, and 4 weeks and retrospectively (15 eyes per IOL) 1 year after cataract surgery. A capsular bend index was developed to document and categorize the capsular bend formation process at the IOL optic edge. Results The anterior and posterior capsules adhered, with the latter attracted to the former. The adhesion always progressed from the periphery to the optic edge so that the posterior capsule eventually wrapped around the posterior optic edge, although not fully circumferentially in all cases. The process took place in 4 stages. Capsular bend formation was complete 1 month after surgery with the foldable IOLs (AcrySof, PhacoFlex II) but was significantly delayed with the PMMA IOL. After 1 year, the capsular wrapping was firm and fully circumferential at the optic edge with all IOL types in all cases. Conclusions Capsular bend formation progressed in the same fashion but at significantly different speeds among the IOLs, suggesting that the process depends on IOL material and design. Fast, early capsular bend formation may be 1 reason AcrySof and PhacoFlex II IOLs prevent PCO statistically better than PMMA IOLs. The results indicate that PCO is prevented by the sharp capsular bend created by sharp optic edges and by quick bend formation.

Pupillometry in seals and sea lions: ecological implications

Phocid and otariid pinnipeds forage almost exclusively under water, where observing them is difficult. As a result, little is known of how their senses are used while diving to locate and capture prey. In this study we used pupillometric methods to describe the relative visual abilities of three pinniped species: the northern elephant seal (Mirounga angustirostris), the harbor seal (Phoca vitulina), and the California sea lion (Zalophus californianus). The range of pupillary area and lower limit of pupillary adjustment were determined for each species. The northern elephant seal exhibited the largest range of pupillary area of the species examined. Furthermore, the elephant seal's pupil was found to reach maximum size only under extremely dim conditions. Both the harbor seal and California sea lion exhibited maximum pupillary dilation in conditions several log units brighter. These results indicate that the elephant seal's visual system is designed to function in dimmer conditions and to respond to greater changes in light levels than those of the harbor seal and sea lion. Such findings support the hypothesis that the visual systems of these pinnipeds are adapted for use in their respective foraging environments, and thus suggest that the visual sense is probably an important sensory modality used to locate and capture prey while diving.