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At least 307 records · Page 17Linked to original sources
PubMed2006

Pupil abnormalities in selected autonomic neuropathies.

Examination of the pupil provides an opportunity to detect disturbances in the autonomic innervation of the eye. The pupil is frequently affected in patients with generalized autonomic neuropathies. This literature review confirms a high prevalence of sympathetic deficits and parasympathetic deficits in acute or subacute dysautonomia, diabetes, amyloidosis, pure autonomic failure, paraneoplastic syndromes, Sjögren syndrome, familial dysautonomia, and dopamine beta-hydroxylase deficiency. It confirms the relative scarcity of a pupil abnormality in patients with multiple system atrophy. There are difficulties in clinical diagnosis of pupil abnormalities and interpretation of pupil pharmacologic tests, particularly when combined sympathetic and parasympathetic deficits are present.

Amyloidosis↗
PubMed2004

Pupil size and night vision disturbances after LASIK for myopia.

PURPOSE: To examine whether standardized, preoperative evaluation of pupil sizes can predict the risk of night vision visual disturbances after bilateral laser in situ keratomileusis (LASIK) for myopia. METHODS: A prospective study was carried out involving 46 patients who underwent bilateral LASIK for myopia. Pupil sizes were measured before surgery using an infrared pupillometer under standardized settings. Pre- and postoperative refraction and best spectacle-corrected visual acuity (BSCVA) were registered. At the 3-month follow-up visit, the patients completed a questionnaire regarding night vision pre- and postoperatively. RESULTS: The mean bilateral, spherical equivalent refraction (SE) was - 8.76 D (range 6.32 to - 12.0 D) preoperatively, and - 1.69 D (range 0 to - 4.38 D) postoperatively. The mean bilateral BSCVA was not changed by the operations. We found a significant correlation between large scotopic pupil sizes and the impression of worsened night vision (p < 0.01). A significant correlation between gender (males) and subjectively reduced night vision postoperatively was also found (p < 0.05). CONCLUSION: Large pupil size measured preoperatively is correlated with an increased frequency of subjectively experienced post-LASIK visual disturbances during scotopic conditions. We recommend preoperative evaluation of pupil size in all patients prior to LASIK surgery.

Adult↗
PubMedDate not supplied

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye.

OBJECTIVE: To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats. ANIMALS STUDIED: The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size. RESULTS: Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (<or= 1 mm difference). One per cent atropine showed a maximal mean difference of 4.3 mmHg +/- 4.1 mmHg in IOP compared to the untreated eye. These differences were statistically significant at 1, 3, 6, 12 and 16 h post-treatment. At 1, 1.5 and 2 h after unilateral application of 1% cyclopentolate, the IOP in the treated eye was significantly higher than the IOP in the untreated eye with a maximal mean difference of 4.1 mmHg +/- 4.5 mmHg. With 0.5% tropicamide, IOP of the treated eye was significantly higher than IOP of the untreated eye at 1 and 1.5 h after treatment with a maximal mean difference of 3.5 mmHg +/- 3.3 mmHg. One per cent atropine caused the greatest increase in IOP, followed by 1% cyclopentolate and 0.5% tropicamide. The dilating effect of atropine, cyclopentolate and tropicamide lasted longer than the effect on intraocular pressure. CONCLUSIONS: The parasympatholytics 1% atropine, 1% cyclopentolate and 0.5% tropicamide caused a statistically significant elevation of IOP and produced mydriasis in the treated eye in normal cats, while the sympathomimetic 10% phenylephrine had no significant effect on IOP or pupil size.

Administration, Topical↗
PubMed2004

Simultaneous continuous recording of accommodation and pupil size using the modified Shin-Nippon SRW-5000 autorefractor.

The internal optics of the recent models of the Shin-Nippon SRW-5000 autorefractor (also marketed as the Grand Seiko WV-500) have been modified by the manufacturer so that the infrared measurement ring has been replaced by pairs of horizontal and vertical infrared bars, on either side of fixation. The binocular, open field-of-view, allowing the accommodative state to be objectively monitored while a natural environment is viewed, has made the SRW-5000 a valuable tool in further understanding the nature of the oculomotor response. It is shown that the root-mean-square of model eye measures was least (0.017 +/- 0.002 D) when the separation of the horizontal measurement bars were averaged twice. The separation of the horizontal bars changes by 3.59 pixels/dioptre (r2 = 0.99), allowing continuous on-line analysis of the refractive state at up to 60 Hz temporal resolution to an accuracy of <0.001 D, with pupils >3 mm. The pupil edge is not obscured in the diagonal axis by the measurement bars, unlike the ring of the original optics, so in the newer model pupil size can be measured simultaneously at the same rate with a resolution of <0.001 mm. The measurements of accommodation and pupil size are relatively unaffected by eccentricity of viewing up to +/-10 degrees from the visual axis and instrument focusing inaccuracies over a range of 10 mm towards the eye and 5 mm away from the eye. The resolution and temporal properties of the analysis are therefore ideal for the simultaneous measurement of dynamic accommodation and pupil responses.

Accommodation, Ocular↗
PubMed1967

Visual resolution when light enters the eye through different parts of the pupil.

1. Threshold contrasts for resolution of sinusoidal gratings imaged on to the retina through a decentred 2 mm pupil were measured.2. No loss in resolution was found when the pupil was decentred parallel to the lines of the gratings. A loss in resolution by a factor of 3 occurred when the pupil was decentred by 3 mm perpendicular to the lines of the gratings.3. The effects of focus on the threshold contrast for a grating viewed through a centred and decentred pupil were used to show that at least a portion of the loss in resolution is due to optical aberrations.4. Using a neon-helium gas laser as a coherent light source, interference fringes were produced on the retina directly. Threshold contrasts for resolution of the fringes were determined for different positions of entry of the beams of light through the pupil. When the Stiles-Crawford brightness effect was compensated for, no loss in resolution was found to occur for decentred entry of the beams.5. It is concluded that the off-axis loss of visual acuity is wholly due to optical aberrations in the eye.6. The ratios between the threshold contrasts for sinusoidal gratings and for interference fringes are used to calculate the optical transfer functions of the off-axis aberrations of the eye.

Humans↗
PubMedDate not supplied

Fast assessment of the central macular pigment density with natural pupil using the macular pigment reflectometer.

We built a new macular pigment reflectometer (MPR) for fast and objective measuring of the optical density of macular pigment in the human eye, using the undilated eye. The design is based on the spectral reflectance from a spot of white light at the fovea. To evaluate its performance, we measured the macular pigment of 20 healthy subjects, ages 18 to 79 years, under four conditions: (1) natural pupil in the dark, (2) natural pupil with dim room light, (3) dilated pupil in the dark, and for comparison with a different technique, (4) heterochromatic flicker photometry (HFP) in dim room light with natural pupil. Condition 1 was repeated in a subset of 10 subjects after an interval of at least 3 days. Data analysis with a model of reflectors and absorbers in the eye provided the density of the macular pigment in conditions 1 to 3. Dim room light and pupil dilatation had no influence on measured density. Mean within subjects variation was typically 7%. Mean difference between test and retest after at least 3 days was 1%. Correlation between MPR and HFP was r=0.56 (p=0.012). Mean within subjects variation with HFP was 19%. The new instrument holds promise for specific applications such as epidemiological research.

Computer Systems↗
PubMed2006

Subretinal membranes are associated with abnormal degrees of pupil "evasion": an index of clinical macular dysfunction.

AIM: To assess whether macular dysfunction caused by unilateral subretinal neovascular membranes (SRNs) is associated with pupil "evasion" (that is, increased initial rate of re-dilation following a brief light stimulus). METHODS: Comparative observational series. 20 eyes of 10 participants, all with unilateral SRNs and healthy fellow eyes. Dynamic infrared pupillography at seven stimulus intensities (duration 1100 ms, intensities over 2 log unit range). Pupil evasion ratio (PEVR; defined as the ratio of light response amplitude to amount of recovery at the mid-time point of re-dilation expressed as a percentage) was calculated for each stimulus intensity (mean of five recordings). RESULTS: Inter-eye PEVR is significantly reduced in eyes with SRN (that is, greater pupil evasion in SRN eyes: range p = 0.002 to p = 0.05 (paired t test)) and is most apparent at higher stimulus intensities. CONCLUSIONS: PEVR is a novel parameter that is analogous to the pupil escape ratio, but measured following a short rather than a sustained light stimulus. PEVR is significantly altered by macular disease. Clinically PEVR may be used to detect occult unilateral or asymmetric maculopathy in situations such as ocular media opacities like cataract, when pupil reactions are unaffected or augmented, while other tests of retinal function are diminished. PEVR represents altered neuronal firing in cones and macular ganglion cells.

Adult↗
PubMed1975

The paretic pupil: its incidence and aetiology after keratoplasty for keratoconus.

The present study reveals that pupillary abnormalities are common after keratoplasty for keratoconus and that, in addition to the fixed dilated pupils which we have found in 7.8 per cent. of eyes, varying degrees of partially dilated pupil frequently occur after operation. In our experience, glaucoma is not a sequel to the simple paretic pupil, a finding which confirms the results of the smaller series of Alberth and Schnitzler (1971); glaucoma thus seems to be no more a special complication of keratoplasty for keratoconus than it is of keratoplasty for any other corneal pathology. The paretic pupils can be explained on the basis of ischaemic atrophy of the sphincter pupillae muscle secondary to an iris strangulation phenomenon occurring during surgery in the manner we have discussed. The relative frequency of a dilated pupil, together with the common finding of focal iris atrophy after minimal surgical trauma to the iris in cases of keratoconus, forces one to conclude that the pathology in this condition is not confined to the cornea but probably extends to the iris and possibly to the scleral envelope as well.

Atrophy↗
PubMed1995

Comparison of the effects on pupil size and accommodation of three regimens of topical dapiprazole.

BACKGROUND: Patients who have their pupils dilated for an eye examination traditionally have to wait several hours before their pupils return to normal size and their blurred vision (caused by paralysis of accommodation) resolves. Earlier studies with dapiprazole have demonstrated an accelerated reversal of dilatation. METHODS: Three regimens of dapiprazole were studied to determine the effects on pupil diameter and accommodation after mydriasis produced by 2.5% phenylephrine and 0.5% tropicamide. Test regimens included one drop and 1 + 1 drop regimens, compared with a 2 + 2 drop reference regimen. Dapiprazole was administered in one eye and placebo in the other. Mean change from baseline was analysed for pupil diameter and accommodation at various time points after drug administration. Also, for the same variables, 90% confidence intervals for the areas under the curve (AUC) were computed. RESULTS: Both test regimens were equivalent to the reference regimen on the basis of mean change from baseline for pupil diameter and accommodation at individual time points, and for the mean AUC. Most signs and symptoms (injection, stinging, burning, lid oedema, and ptosis) were less frequent in the test regimen treated eyes. There was no significant interaction between regimen and eye colour. CONCLUSION: This study indicates that a lower dosage (for example, one drop) is also efficacious and has the added benefit of fewer side effects.

Accommodation, Ocular↗
PubMed2000

Factors affecting pupil size after dilatation: the Twin Eye Study.

BACKGROUND/AIMS: Well dilated pupils make eye surgery easier. A classic twin study was established to examine the relative importance of genes and environment in the variance of pupil size after mydriasis, and to examine the effects of other factors such as age, iris colour, and refractive error. METHODS: 506 twin pairs, 226 monozygotic (MZ) and 280 dizygotic (DZ), aged 49-79 (mean age 62.2 years, SD 5.7) were examined. Dilated pupil size was measured using a standardised grid superimposed over digital retroillumination images taken 50-70 minutes after mydriasis using tropicamide 1% and phenylephrine 10%. Univariate maximum likelihood model fitting was used to estimate genetic and environmental variance components. RESULTS: Dilated pupil size was more highly correlated in MZ compared with DZ twins (intraclass correlation coefficients 0.82 and 0.39 respectively). A model specifying additive genetic and unique environmental factors showed the best fit to the data, yielding a heritability of 78-80%. Individual environmental factors explained 18-19% of the variance in this population. Age only accounted for 2-3% of the variance and refractive error and iris colour did not significantly contribute to the variance. CONCLUSIONS: Pupil size after mydriasis is largely genetically determined, with a heritability of up to 80%.

Aged↗
PubMed1999

Pupil abnormality in amyloidosis with autonomic neuropathy.

Darkness pupil diameters, light reflexes, and redilatation times have been recorded with infrared TV pupillometry in 12 consecutive patients with systemic amyloidosis associated with sensory motor and autonomic neuropathy. Nine of the patients had AL amyloidosis, two had familial amyloidosis associated with a transthyretin abnormality, and one was untyped. The pupils were abnormal in all 12 patients. On the basis of redilatation lag without pupillotonia, six patients had bilateral Horner's syndrome and in one of them amyloid deposits were found in a sympathetic ganglion and in the attached sympathetic chain obtained at necropsy. Four patients had bilateral tonic pupils with light-near dissociation and two had abnormally small pupils with reduced light reactions which could not be characterised. It seems that in patients with systemic amyloidosis generalised autonomic neuropathy is strongly associated with pupil abnormality as shown by tonic reactions with light-near dissociation, by redilatation lag, or by reduced size in darkness.

Adult↗
PubMed1992

Optimal pupil diameter for Scheimpflug slit image photography of the lens in man.

Densitometric analysis of Scheimpflug photography of the lens has been examined as a function of pupil diameter in normal volunteers. On the basis of both the length of the lens waveform and the integral area under the curve of the lens waveform, there is a critical pupil diameter above which the waveform is unchanged. Below this critical diameter the waveform becomes distorted by shortening and a change in shape. The critical pupil diameter is between 6 and 6.5 mm. This result is of importance either in longitudinal studies, where the pupil diameter may not be reproducible, or in studies where other drugs are used which may prevent full pupil dilatation.

Adult↗
PubMed1999

The effects of the novel anxiolytic drug lesopitron, a full and selective 5-HT1A receptor agonist, on pupil diameter and oral temperature in man: comparison with buspirone.

We investigated the effects of two 5-HT1A receptor agonists, buspirone and lesopitron, upon pupil size in human volunteers at an ambient luminance level of 32 Cd m(-2) and in darkness. Pupil diameter was monitored with a binocular infrared television pupillometer, before and after the administration of treatments for 4 h at 20-min intervals. Two experiments were conducted. In Experiment 1, 14 healthy male volunteers participated in seven weekly sessions, each associated with the ingestion of one capsule (buspirone 5, 10 and 20 mg, lesopitron 10, 20 and 40 mg and placebo), according to a double-blind balanced, cross-over design. Both buspirone and lesopitron tended to decrease pupil diameter. In darkness, only the highest dose of buspirone (20 mg) caused a miosis that was statistically significant. However, at the luminance level of 32 Cd m(-2) buspirone 10 and 20 mg evoked statistically significant miotic effects, as did the highest dose of lesopitron (40 mg). The miotic effect was significantly greater at 32 Cd m(-2) than in darkness after each dose of buspirone and the highest dose (40 mg) of lesopitron. In Experiment 2, pupil diameter and oral temperature were monitored with an electronic thermometer at 40-min intervals. Twenty healthy male volunteers participated in two weekly sessions, each associated with the sublingual application of 100 microl hydroalcoholic solution (lesopitron 20 mg, placebo), according to a double-blind balanced cross-over design. Lesopitron caused a significant miosis both in darkness and at the luminance level of 32 Cd m(-2); the miosis was greater at 32 Cd m(-2) than in darkness. Lesopitron tended to decrease oral temperature; this effect however, was not statistically significant. The greater effectiveness on the pupil of lesopitron administered sublingually in a solution indicates the importance of first-pass metabolism in reducing the effectiveness of the drug when administered by the mouth. The miosis observed in both experiments may be due to either a sympatholytic or a parasympathomimetic effect of the drugs, or both. The light-dependence of the miosis indicates that the 5-HT1A receptor agonists can modulate the light reflex, possibly via the noradrenergic control of central cholinergic neurones in the Edinger-Westphal nucleus.

Adult↗
PubMed1993

Pupil size regulation of threshold of light-induced melatonin suppression.

The capacity of pupil dilation to affect light-induced plasma melatonin suppression was tested by exposing human subjects with freely constricting or pharmacologically dilated pupils to either 50 (n = 6), 100 (n = 8), or 200 lux (n = 5) of white light presented over the entire visual field. Pupil dilation significantly enhanced low level white light-induced melatonin suppression over that elicited with freely constricting pupils. Although 100 and 200 lux white light exposures resulted in significant melatonin suppression over control (no light) conditions, the effects of 50 lux were not strong enough to demonstrate statistically significant suppression with six subjects. Linear regression did not reveal a systematic relationship between theoretical retinal illuminance in Trolands and magnitude of melatonin suppression. These results suggest that pupil diameter may be a factor in the effectiveness of light stimuli used to shift circadian rhythms or to treat seasonal depression or sleep disorders.

Adult↗
PubMed1990

The opposite pupil in herniation.

I serially examined the pupil opposite the one already enlarged from transtentorial herniation in 13 patients. The main abnormalities, stereotyped in most patients, were an initially diminished light reaction with a 2.5- to 4-mm-diameter pupil, followed by slight reduction in size, and then reenlargement to greater than original size, all with preserved roundness. Subsequent deterioration varied among patients, but a transitional oval shape was infrequent and oculomotor function was preserved until both pupils were enlarged and fixed. Once the pupil on the side of a mass enlarges, heralding herniation, subsequent deterioration can be appreciated through changes in reactivity and size of the opposite pupil.

Encephalocele↗
PubMed2002

Comparison of exact pupil astigmatism conditions with Seidel approximations.

The aberrations of axisymmetric imaging systems can be calculated to third order by use of the Seidel formula. The Coddington equations give aberrations that have quadratic dependence on the pupil, for all field points. The pupil astigmatism conditions were recently developed to predict and control aberrations that have quadratic field dependence and arbitrary pupil dependence. We investigate the relationship between the exact pupil astigmatism conditions and the classical Seidel treatment of pupil aberration.

Astigmatism↗
PubMed1994

Monochromatic modulation transfer function of the human eye for different pupil diameters: an analytical expression.

The modulation transfer function (MTF) of human eyes for different pupil sizes was measured in a group of normal young subjects by use of a double-pass method. Measurements were carried out in the fovea, with monochromatic red light, paralyzed accommodation, artificial pupils, and optimum spherical refraction in each subject. For each pupil size both the averaged MTF and the intersubject variability were calculated. MTF's were approximated by the sum of two exponential functions. This three-parameter function provides a better approximation to our ocular MTF's than do most of the previous parametric models (usually one exponential), especially at intermediate and high spatial frequencies. Further curve fitting of the parameters allowed us to obtain a general expression for the mean MTF as a function of both pupil diameter and normalized spatial frequency. This equation summarizes our estimates of the average monochromatic retinal image quality of the human eye for any pupil diameter with good accuracy and in a compact way, which allows one to incorporate the eye's image quality easily in any particular study.

Adult↗
PubMed2002

Pupil signs of sympathetic autonomic neuropathy in patients with type 1 diabetes.

OBJECTIVE: Pupillary autonomic neuropathy is considered an early sign of the development of systemic autonomic neuropathy. Sympathetic denervation is related to the duration of diabetes and the development of systemic autonomic dysfunction. We investigated pupil responsiveness to directly and indirectly acting sympathomimetics in type 1 diabetic patients with and without long-term complications, defined as cardiac autonomic neuropathy (CAN), peripheral sensomotor neuropathy, retinopathy, and nephropathy, and in healthy subjects. RESEARCH DESIGN AND METHODS: A total of 47 randomly chosen type 1 diabetic patients and 20 healthy subjects were selected for this study. Patients were divided into groups determined by whether they had long-term diabetic complications. Pharmacological tests were performed with cocaine 4%, epinephrine 1%, and pholedrine 5% eye drops. Horizontal pupil diameter (HPD) was measured at the beginning of the pharmacological tests and at defined time points after instillation of the eye drops. RESULTS: Statistical analysis showed a significantly smaller HPD in the patients before instillating eye drops (P = 0.011). In particular, the HPD was significantly smaller in the patient group without CAN when compared with healthy subjects (P = 0.004). Maximal cocaine reaction was diminished in the complication group (P < 0.001). Epinephrine test, visual acuity, ocular pressure, and HbA(1c) did not differ in patients with or without long-term complications. The noncomplication group showed no significant differences in pupillary responses as compared with healthy subjects. The complication group showed a smaller HPD (P = 0.022), reduced pupillary responses in the cocaine (P = 0.037) and pholedrine tests (P < 0.001), and anisocor pupil sizes after instillation of the eye drops (P = 0.034). CONCLUSIONS: Our results clearly show that sympathetic denervation does exist in the pupil of diabetic patients and that it can be rapidly assessed using the cocaine test. These data and the results of the epinephrine test suggest a mixed pre- and postganglionic dysfunction of the sympathetic plexus. The significant smaller HPD in patients without CAN compared with that of healthy subjects could be a sign for early involvement of the pupil function before cardiac manifestation of systemic autonomic diabetic neuropathy.

Adult↗