Difference In Pupil Diameter Research Articles

Wait before extrapolating rather than wait between two eyedrops! … The 1974 Chrai et al.'s study on the albino rabbit may not apply to humans

PurposeThe recommendation of having patients waiting 5 minutes between two eyedrops instillation is based on an experimental work conducted by Chrai et al. in 1974 on the albino rabbit. In this work, instillation of pilocarpine eyedrops was followed by instillation of saline eyedrops after 30 seconds and 2 minutes with as few as 4 rabbits and permitted a decreasing of the maximum difference in pupillary diameter respectively by 44% and 17.5%. The present study was undertaken to assess the validity of these findings in humans.MethodsTwenty‐four healthy volunteers were enrolled from March 2016 to April 2017. Eyeballs were photographed in a completely dark room with an infrared camera at baseline, 40 minutes after instillation of 1% pilocarpine and 40 minutes after instillation of 1% pilocarpine eyedrops followed by the instillation of saline eyedrops immediately afterwards or 5 minutes later. Pupil to iris surface ratios were calculated and differences of ratios between baseline and 40 minutes (i.e. myosis gain) were compared with Wilcoxon test.ResultsThe mean (SD) myosis gain was 0.176 (0.089) with 1% pilocarpine alone; 0.165 (0.086) with 1% pilocarpine immediately followed by saline eyedrops (p = 0.652) and 0.167 (0.087) with pilocarpine followed 5 minutes later by saline eyedrops (p = 0.731). Only some eye colours significantly influenced the myosis gain in multivariate analysis.ConclusionsDespite using pupil/iris surface ratios (more sensitive than diameter measurements), and more subjects (24 versus 4) our study fails to confirm the results found by Chrai et al.'s in the albino rabbits. While awaiting for the issue of the time interval between eyedrops in humans to be further investigated, one should be cautious with extrapolation of Chrai et al.'s conclusions in the albino rabbits to humans.

The Effects of Age, Refractive Status, and Luminance on Pupil Size.

ABSTRACTPurposePupil size is critical for optimal performance of presbyopic contact lenses. Although the effect of luminance is well known, little information is available regarding other contributing factors such as aging and refractive status.MethodsThe cohort population comprised 304 patients (127 male, 177 female) aged 18 to 78 years. Pupils were photographed at three controlled luminance levels 250, 50, and 2.5 cd/m2 using an infra-red macro video camera. Measurements of pupil diameter were conducted after transforming pixel values to linear values in millimeters.ResultsLuminance was the most influential factor with pupil diameter increasing with decreased luminance (p < 0.001, all comparisons). Age was also found to be a significant factor with a smaller diameter in the older groups, but overall the difference was only significant between the pre-presbyopes and the established presbyopes (p = 0.017). Pupil diameter decreased significantly with increasing age, the effect being most marked at low luminance (<0.001). The smallest pupil diameters were measured for hyperopes and the largest for myopes and although refractive error was not a significant factor alone, there was a significant interaction between luminance and refractive error with the greatest differences in pupil diameter between myopes and emmetropes at low luminance (p < 0.001). Pupil diameter changes modeled by multilinear regression (p < 0.001) identified age, luminance, best sphere refraction, and refractive error as significant factors accounting for just over 70% of the average variation in pupil diameter.ConclusionsBoth age and refractive status were found to affect pupil size with larger pupils measured for younger patients and myopes. Designs for multifocal contact lens corrections should take both age and refractive status into consideration; a faster progression from distance to near corrections across the optical zone of the lens is expected to be required for established presbyopes and hyperopes than it is for early presbyopes, myopes, and emmetropes.

Are people emotionally aroused by hypothetical medical scenarios in experiments? An eye tracking study with pupil dilation

Background: Many studies on the communication of medical risks use hypothetical medical scenarios. The results of these scenarios should have sufficient predictive accuracy to be generalized to real life; thus, it is important to know whether hypothetical medical scenarios work and whether there is a relationship between risk level and emotional arousal. Methods: In an eye tracking experiment (N = 67), we investigated the influence of a simple hypothetical medical scenario on pupil dilation, a measure of emotional arousal. In this medical scenario, the participants were shown three risk levels (low, middle, and high) and had to estimate the probability that a hypothetical patient has colon cancer. They were also given a non-medical scenario that controlled for changes in illumination and cognitive workload. Therefore, we supposed that the difference in pupil diameter between the medical and the non-medical scenario was due to emotional arousal. Results: We found that our hypothetical medical scenario had a significant effect on pupil diameter. The mean values of the mean pupil diameter in the first fifth of the fixations were higher for all risk levels in the medical scenario than in the non-medical scenario. In a more detailed analysis of the difference in pupil diameters between the two scenarios, we detected that, for the high-risk level, the emotional difference values (between the medical and non-medical scenarios) differed significantly from zero. Furthermore, we found that higher risk levels lead to higher emotional arousal and higher probability estimates. Conclusions: Even simple hypothetical medical scenarios cause emotional arousal. Thus, hypothetical medical scenarios work, and the results of studies not using real patients can be generalized to real medical situations.

Comparison of Preoperative Topical Dexamethasone Phosphate Versus Ketorolac Tromethamine in Maintaining Intraoperative Mydriasis During Small Incision Cataract Surgery.

Intraoperative miosis is one of the many challenges which a surgeon can face during cataract surgery. It may lead to impaired view and difficulty in delivering the nucleus. Also, it increases the chances of more serious intraoperative and postoperative complications. Therefore, maintaining adequate pupillary dilatation is of utmost importance during cataract surgery. To study the efficacy of topical dexamethasone phosphate (0.1%) and topical ketorolac tromethamine (0.4%) in maintaining pupillary dilatation during cataract surgery. A total of 200 patients were studied. These were randomly divided into two groups of 100 each. Group1 was given topical dexamethasone phosphate (0.1%) and Group 2, topical ketorolac tromethamine (0.4%). Medications were started 1-day before surgery in the form of one drop to be instilled every 6 hours. Pupillary diameter was measured in the horizontal meridian; 4 readings were taken - before making the incision, after nucleus delivery, following cortical clean-up and after Intraocular Lens (IOL) implantation. The two drugs showed no statistically significant difference in pupillary diameter at the commencement of surgery (p=0.435). The difference between the two drugs was statistically significant, for the mean pupillary diameter which changed from the start of surgery to after cortical clean-up. At this stage, ketorolac group showed a tendency towards larger mean pupillary diameter than dexamethasone group (6.70 ± 0.85mm and 6.32 ± 0.84mm, respectively, p=0.002). Again, ketorolac group patients had larger pupillary diameter after IOL implantation than dexamethasone group patients (the mean was 6.16± 0.97mm and 5.75 ± 0.73mm, respectively, p=0.001). Both ketorolac tromethamine (0.4%) and dexamethasone phosphate (0.1%) are effective in maintaining adequate mydriasis during cataract surgery, but the comparative analysis of the two drugs concludes that, ketorolac is definitely a better option in preventing surgically induced miosis.

Evaluation of the mydriatic effects of topical administration of rocuronium bromide in Hispaniolan Amazon parrots (Amazona ventralis).

OBJECTIVE :To determine the mydriatic effects of topical rocuronium bromide administration in Hispaniolan Amazon parrots (Amazona ventralis) and to identify any adverse effects associated with treatment. Randomized crossover study. 8 healthy adult Hispaniolan Amazon parrots. Rocuronium bromide (20 μL/eye; 10 mg/mL) or saline (20 μL/eye; 0.9% NaCl) solution was administered in both eyes of each bird with a 26-day washout period. The birds were manually restrained in lateral recumbency with the apex of the cornea positioned upward for 2 minutes following administration in each eye. Infrared pupillometry and direct pupillary light reflex measurements were used to evaluate the mydriatic effects. Pupillary measurements were recorded prior to administration and every 20 minutes for 2 hours after administration, then hourly for a total of 7 hours. A brief physical examination was performed, direct pupillary light reflex was tested, and fluorescein staining was performed on each eye of each bird 24 hours after administration. A significant difference in pupillary diameter for the active versus control treatment group was noted from 20 to 360 minutes after drug administration, but not at 420 minutes. Minimal adverse effects were noted. Three birds had transient inferior eyelid paresis noted in both eyes after receiving rocuronium; 24 hours after the treatment, no differences in ocular measurements existed between the active and control treatments. Results suggested that topical rocuronium bromide administration may be safely used for pupillary dilation in Hispaniolan Amazon parrots and could be used for clinical evaluation, fundus imaging, and surgical interventions involving the lens and posterior segment in this species.

Pupillometry in brain death: differences in pupillary diameter between paediatric and adult subjects

Objectives:The determination of brain death in neonates, infants, children and adults relies on a clinical diagnosis based on the absence of neurological function with a known irreversible cause of brain injury. Evaluation of pupil size and non-reactivity is a requisite for determination of brain death. There are no studies in the literature that quantitatively assess pupil size in brain dead children and adults.Methods:Infants, children and adults diagnosed with brain death were included in the study. Pupils were measured with a quantitative pupillometer (Forsite; Neuroptics, Irvine, CA, USA). Median, minimum and maximum pupil sizes were documented and the results were adjudicated for age, vasopressor use and temperature.Results:Median right and left pupil sizes were 5.01 ± 0.85 mm and 5.12 ± 0.87 mm, respectively, with a range between 3.69 and 7.34 mm. Paediatric pupils were larger than adult pupils (right pupil 5.53 vs 4.73 mm p: 0.018; left pupil 5.87 vs 4.77 mm P: 0.03), and there was no correlation of pupil size with temperature or increasing number of vasopressors.Conclusion:This is the first study in the literature objectively evaluating pupil sizes in infants, children and adults diagnosed with brain death. We observed variation between observed pupil size and that expected based on brain death determination guidelines.

Is Pupil Diameter Influenced by Refractive Error?

To investigate the relationship between pupil diameter and refractive error and how refractive correction, target luminance, and accommodation modulate this relationship. Sixty emmetropic, myopic, and hyperopic subjects (age range, 18 to 35 years) viewed an illuminated target (luminance: 10, 100, 200, 400, 1000, 2000, and 4100 cd/m) within a Badal optical system, at 0 diopters (D) and -3 D vergence, with and without refractive correction. Refractive error was corrected using daily disposable contact lenses. Pupil diameter and accommodation were recorded continuously using a commercially available photorefractor. No significant difference in pupil diameter was found between the refractive groups at 0 D or -3 D target vergence, in the corrected or uncorrected conditions. As expected, pupil diameter decreased with increasing luminance. Target vergence had no significant influence on pupil diameter. In the corrected condition, at 0 D target vergence, the accommodation response was similar in all refractive groups. At -3 D target vergence, the emmetropic and myopic groups accommodated significantly more than the hyperopic group at all luminance levels. There was no correlation between accommodation response and pupil diameter or refractive error in any refractive group. In the uncorrected condition, the accommodation response was significantly greater in the hyperopic group than in the myopic group at all luminance levels, particularly for near viewing. In the hyperopic group, the accommodation response was significantly correlated with refractive error but not pupil diameter. In the myopic group, accommodation response level was not correlated with refractive error or pupil diameter. Refractive error has no influence on pupil diameter, irrespective of refractive correction or accommodative demand. This suggests that the pupil is controlled by the pupillary light reflex and is not driven by retinal blur.

Memory, emotion, and pupil diameter: Repetition of natural scenes

Recent studies have suggested that pupil diameter, like the "old-new" ERP, may be a measure of memory. Because the amplitude of the old-new ERP is enhanced for items encoded in the context of repetitions that are distributed (spaced), compared to massed (contiguous), we investigated whether pupil diameter is similarly sensitive to repetition. Emotional and neutral pictures of natural scenes were viewed once or repeated with massed (contiguous) or distributed (spaced) repetition during incidental free viewing and then tested on an explicit recognition test. Although an old-new difference in pupil diameter was found during successful recognition, pupil diameter was not enhanced for distributed, compared to massed, repetitions during either recognition or initial free viewing. Moreover, whereas a significant old-new difference was found for erotic scenes that had been seen only once during encoding, this difference was absent when erotic scenes were repeated. Taken together, the data suggest that pupil diameter is not a straightforward index of prior occurrence for natural scenes.

Prediction of movement to surgical stimulation by the pupillary dilatation reflex amplitude evoked by a standardized noxious test.

Individual assessment of the amplitude of a physiologic reflex evoked by a standardized noxious test (SNT) before surgical stimulation has been suggested to predict movement upon the forthcoming surgical stimulation. This study aimed to compare the ability of pupillary dilatation reflex amplitude (PDRA) evoked by an SNT and estimated remifentanil effect-site concentration (Ce) to predict movement upon surgical stimulation. Eighty female patients were anesthetized for vacuum aspiration with propofol (Ce 4 μg/ml) and remifentanil. Remifentanil Ce was randomized to 0, 1, 3, or 5 ng/ml. SNT was a 60-mA, 5-s, 100-Hz tetanus applied on median nerve before cervix dilatation. PDRA was calculated as the difference in pupillary diameter after and before SNT. Movement upon cervix dilatation was recorded by an independent observer. Ability of PDRA and estimated remifentanil Ce to discriminate movers from non-movers during cervix dilatation was measured as the area under the receiver operating characteristics curve. Twenty-one of the 76 patients analyzed moved during cervix dilatation. Mean PDRA (±1 SD) evoked by SNT was 2.0 ± 1.2 mm in movers and 0.6 ± 0.7 in non-movers (P < 0.0001). Remifentanil Ce was 0.2 ± 0.4 ng/ml in movers and 3.0 ± 1.7 in non-movers (P < 0.0001). Area under the receiver operating characteristics curve for PDRA was 0.90 (95% CI, 0.83 to 0.96) and for remifentanil Ce 0.94 (0.89 to 0.98), without any significant difference between the two areas. PDRA evoked by an SNT is as accurate as the estimated remifentanil Ce to predict movement upon cervix dilatation. PDRA could be valuable when estimated opioid Ce is not available or reliable.

Evaluating the potentiating effect of amethocaine on tropicamide-induced mydriasis in darkly pigmented irides, using infrared pupillometry.

PURPOSETo determine whether prior instillation of amethocaine would increase the rate and magnitude of tropicamide-induced pupillary dilatation in darkly pigmented irides.METHODA total of 50 healthy Africans aged 18–40 years, with darkly pigmented irides, received a drop of amethocaine in one eye and a drop of placebo in the contralateral eye, followed by two drops of tropicamide in both eyes. Serial pupil diameters were measured using a monocular infrared video pupillometer. Rate of pupillary dilatation was compared in both eyes. Survival statistics were calculated for the time taken to reach a clinically effective dilatation, clinically effective diameter (CED) of 6.0 mm.RESULTSMean difference in pupil diameters between amethocaine- and placebo-treated eyes was 0.30 ± 0.09 mm (P < 0.002). In all, 62% of amethocaine-treated eyes and only 46% of placebo-treated eyes reached the CED.CONCLUSIONWe observed a small but statistically significant potentiating effect of a drop of amethocaine on tropicamide-induced dilatation within 20 minutes.

Everyday anisocoria: Anisocoria epidemiology in a secondary care setting

ObjectiveTo determine the relative importance of the different forms of anisocoria in a General Hospital. MethodsA prospective, longitudinal study was conducted including all patients referred for this reason to the Neuro-Ophthalmology Unit of the Henares University Hospital, Madrid, Spain, from November 2008 to October 2011. The differences in pupil diameter were studied under high and low luminosity. The patients were given a full ophthalmological examination, as well as performing the apraclonidine, cocaine, pilocarpine 0.125% and pilocarpine 2% tests, if they were considered necessary. ResultsThirty-two cases of anisocoria were referred during the three years of the study. No relationship was found with age or gender. The diagnostic results were: Adie's pupil, 4 cases; Horner syndrome, 5 cases; benign episodic unilateral mydriasis, 3 cases; local causes, 4 cases; physiological anisocoria, 5 cases. Despite a full clinical history and examination, the cause of the anisocoria could not be determined in 11 cases. In 4 of these cases, the patients suffered from migraines and in another 4 psychotropic drugs were taken. Both risk factors were present in 3 cases. In one case the anisocoria was the initial clue that led to the diagnosis of a cervical paraganglioma. ConclusionsAnisocoria is a clinical sign that does not usually signify a serious disease. With our protocols, a high number of anisocoria cases are still of unknown origin. Migraines and psychotropic drugs could be linked to these forms of anisocoria.

Anisocoria cotidiana: epidemiología de la anisocoria en un centro de nivel secundario

ObjetiveTo determine the relative importance of the different forms of anisocoria in a General Hospital. MethodsA prospective, longitudinal study was conducted including all patients referred for this reason to the Neuro-Ophthalmology Unit of the Henares University Hospital, Madrid (Spain), from November 2008 to October 2011. The differences in pupil diameter were studied under high and low luminosity. The patients were given a full ophthalmological examination, as well as performing the apraclonidine, cocaine, pilocarpine 0.125% and pilocarpine 2% tests, if they were considered necessary. ResultsThirty-two cases of anisocoria were referred during the three years of the study. No relationship was found with age or gender. The diagnostic results were: Adie's pupil, 4 cases; Horner syndrome, 5 cases; benign episodic unilateral mydriasis, 3 cases; local causes, 4 cases; physiological anisocoria, 5 cases. Despite a full clinical history and examination, the cause of the anisocoria could not be determined in 11 cases. In 4 of these cases, the patient suffered from migraines and in another 4 psychotropic drugs were taken. Both risk factors were present in 3 cases. In one case the anisocoria was the initial clue that led to the diagnosis of a cervical paraganglioma. ConclusionsAnisocoria is a clinical sign that does not usually signify a serious disease. With our protocols, a high number of anisocoria cases are still of unknown origin. Migraines and psychotropic drugs could be linked to these forms of anisocoria.

P-302 - Pupillometric assessment of autonomic nervous system functions in children with attention deficit hyperactivity disorder

Introduction Attention deficit and hyperactivity disorder (ADHD) is one of the most frequently seen neurobehavioral disorder in school-aged children. Although the main cause of ADHD is unknown, it's thought that numerous biopsychosocial factors have part in etiology of ADHD together. Objectives/aims This study aims to compare autonomic nervous system functions by measuring pupil diameters in 6–11 aged boys diagnosed ADHD with age and sex matched healthy controls. Methods Thirty-two boys with ADHD and 24 healthy controls were participated into this study. We studied with a more homogeneous group by exclusion of any other psychiatric disorders except oppositional defiant disorder (ODD). The participants were evaluated autonomic nervous system functions by measuring pupil diameter changes in photopic and mesopic conditions. Results There were no statistical differences on photopic and mesopic pupil diameters between ADHD and healthy control groups (p>0.05). Moreover, there were no significant differences on same parameters between pure ADHD and ADHD+ODD groups (p>0.05). Conclusions These findings suggest that boys with ADHD don’t show difference in pupil diameters from typically children. This might indicate no difference in autonomic nervous system functions.

The effects of systemic α1-adrenoreceptor antagonists on pupil diameter

AimTo assess differences in pupil diameter between men taking systemic α1-adrenoreceptor antagonists and controls.SettingUniversity of Michigan clinics, USA.MethodsMale patients over the age of 50 years were recruited from clinics over...

Clinical analysis of pupil features in emmetropia population

目的 研究健康人不同年龄组正视眼在不同光照度下的瞳孔大小及瞳孔震颤特点.方法 收集健康志愿者120例240眼,均为正视眼,男女各半;分为21～30岁、31～40岁和41～50岁3个年龄组,每个年龄组男女各20人.应用P3000型双眼瞳孔测量仪测量各年龄组正视眼瞳孔大小及瞳孔震颤,测量分别在暗视(0.04lx)、低光照度(0.40 lx)和高光照度(4.00 lx)下进行.结果 所有受试者暗视、低光照度及高光照度下瞳孔直径的均值分别为(6.14±0.95)、(4.90±0.99)、(3.81±0.59)mm,瞳孔震颤的均值分别为0.31、0.46、0.39mm,差异均有统计学意义(瞳孔直径:F=323.78,P=0.00;瞳孔震颤:F=16.94,P=0.00).21～30岁、31～40岁和41～50岁组在3种不同光照度下瞳孔直径分别为(6.48±0.67)、(5.19±0.73)、(3.99±0.50)mm;(6.01±1.07)、(4.80±1.10)、(3.77±0.68)mm和(5.62±0.88)、(4.26±0.74)、(3.43±0.43)mm.所有受试者瞳孔直径及瞳孔震颤在不同光照度组间差异均有统计学意义.在不同光照度下不同年龄组间瞳孔直径均值差异均有统计学意义(F=13.20,P=0.00;F=14.87,P=0.00;F=13.31,P=0.00).女性受试者和男性受试者在3种不同光照度下瞳孔直径均值分别为(6.00±0.86)、(6.33±0.99)mm;(4.73±0.83)、(5.11±1.10)mm和(3.73±0.48)、(3.90±0.69)mm,除高光照度组之外,其余2组光照度下男女瞳孔直径均值差异均有统计学意义(暗视:t=-2.50,P=0.01;低光照度:t=-2.57,P=0.01;高光照度:t=-1.76,P=0.08).3种光照度下受检者双眼间瞳孔直径的差异均无统计学意义(暗视:t=0.42,P=0.68;低光照度:t=0.95,P=0.34;高光照度:t=-0.01,P=0.99).结论 瞳孔直径受光照强度、性别和年龄的影响.瞳孔震颤在3种光照度下均可发生,低光照度下更为明显。

Severe Anisocoria after Oral Surgery under General Anesthesia

Anisocoria indicates a difference in pupil diameter. Etiologies of this clinical manifestation usually include systemic causes as neurological or vascular disorders, and local causes as congenital iris disorders and pharmacological effects. We present a case of a 47-year-old man, suffering from spastic tetraparesis. After the oral surgery under general anesthesia, the patient developed severe anisocoria: in particular, a ~4 mm diameter increase of the left pupil compared to the right pupil. We performed Computed Tomography (CT) in the emergency setting, Nuclear magnetic resonance (NMR) of the brain and Magnetic Resonance Angiography of intracranial vessels. These instrumental examinations did not show vascular or neurological diseases. The pupils returned to their physiological condition (isocoria) after about 180 minutes. Literature shows that the cases of anisocoria reported during or after oral surgery are rare occurrences, especially in cases of simple tooth extraction. Anisocoria can manifest in more or less evident forms: therefore, it is clear that knowing this clinical condition is of crucial importance for a correct and timely resolution.

Goal Control of Attention to Advertising: The Yarbus Implication

An eye-tracking experiment with four processing goals and a free-viewing condition reveals goal control of attention even during a few seconds of self-paced ad exposure. An ad-memorization goal enhanced attention to the body text, pictorial, and brand design objects. A brand-learning goal enhanced attention to the body text but simultaneously inhibited attention to the pictorial design. This supports the thesis that ad informativeness is goal contingent. Differences in pupillary diameter between ad objects but not between processing goals reflect the pupil's role in maintaining optimal vision. Implications of the findings for advertising theory and avenues for future research are indicated.

Visual Adaptation to Interocular Brightness Differences Induced by Neutral-Density Filters

Interocular brightness differences such as those caused by asymmetrical cataract have been found to have a minimal effect on interocular brightness matches. In the present study, the measured binocular visual response to interocular differences in retinal illuminance was measured over time. Interocular differences in retinal illuminance of magnitudes 0.3, 0.6, and 0.9 log units were induced using neutral density (ND) filters under two conditions: (1) naturally mobile pupils and (2) with fixed artificial pupils (3 mm). Interocular brightness differences were quantified by measuring interocular brightness matches using the simultaneous interocular brightness sense test every 15 minutes over a 2-hour period in eight visually normal subjects. Initial interocular brightness matches were as predicted by the induced interocular differences in retinal illuminance (P > 0.05). A significant reduction in the interocular difference in brightness was observed over time (P < 0.01). These reductions in the interocular difference in brightness over time followed a logarithmic progression reaching asymptotic values equal to the reciprocal of the square root of the interocular retinal illuminance ratio. This value is equal to the midpoint of the induced interocular difference in retinal illuminance at time 0 and that found without the introduction of the ND filters. Binocular visual adaptation to interocular brightness differences occurred with both mobile and fixed pupils. Visual adaptation occurs in response to interocular brightness differences induced by asymmetrical ND filters. The level of visual adaptation can be predicted by Fechner's Paradox and is independent of interocular differences in pupil diameter.

Efficacy of Apraclonidine 0.5% in the Diagnosis of Horner Syndrome in Pediatric Patients Under Low or High Illumination

To evaluate the efficacy and safety of apraclonidine 0.5% in the diagnosis of Horner syndrome in pediatric patients. Prospective, interventional case series. Ten pediatric patients with a diagnosis of Horner syndrome and 10 age-matched controls with physiologic anisocoria underwent pharmacological testing with apraclonidine. The difference between the pupil diameters of both eyes under low (room light off) and high (room light on) ambient illumination before and one hour after apraclonidine was instilled was recorded. Any adverse effects during the examination or reported by the patient's parents were recorded. The mean differences in pupil diameters before and after apraclonidine testing in the Horner syndrome group were -2.05 mm and 0.97 mm, respectively, under low illumination (P = .0049) and -1.48 mm and 1.1 mm, respectively, under high illumination (P = .0051). Three patients with Horner syndrome showed positive values (reversal of anisocoria) only under high ambient illumination, but not under low illumination. There was no statistical difference in the mean differences in pupil diameter before and after apraclonidine testing in the control group. Conjunctival hyperemia was noted in two patients with Horner syndrome and in three patients in the control group. No systemic adverse effects were noted during the examination or were reported by patients' parents. The application of apraclonidine in pediatric patients is safe and effective in the diagnosis of Horner syndrome. The reversal of anisocoria was more obvious under high (room light on) ambient illumination.

Pupil dilation using a pledget sponge: a randomized controlled trial

To show that a pledget soaked in mydriatics and placed in the lower conjunctival fornix is as effective as drops in providing mydriasis for cataract surgery. A randomized, masked, controlled trial of 56 patients assigned to either a pledget group (n=25) or a control eye drops group (n=31) was carried out. Controls had the routine practice of repeated topical mydriatic drops: tropicamide, phenylepherine and atropine. The trial group had a 3-mm pledget trimmed, soaked in mydriatics and placed in the inferior fornix for 20 min. Pupil diameter was measured using a photographic technique with a standard scale shown in each picture. Two masked observers measured the pupils using the scale of the ruler in the developed photograph. All patients completed a 0-10 stinging score prior to surgery. There were no complications. The mean pupil diameter in the control group was 7.23 (6.91-7.94 95% confidence intervals [CI]) and 7.44 (6.96-7.92 95% CI) in the pledget group. There was no statistically significant difference in pupil diameter between the two groups: difference between means 0.21 (-0.32 to 0.75 95% CI) and Student's t-test of the difference between means (t=0.8 and two-tailed) probability P=0.43. There was no significant difference in the stinging scores: Mann-Whitney test P=0.69. The use of a pledget cellulose sponge to deliver mydriatics prior to cataract surgery is as effective as the conventional method of repeated drop administration and was not associated with any adverse effects.