Administration Of Tropicamide Research Articles

The effect of cycloplegia on intraocular pressure with and without adjusting for central corneal thickness in patients with diabetes mellitus

PurposeTo assess and compare the effects of cycloplegia using 0.5% tropicamide and 1% tropicamide on intraocular pressure (IOP) in patients with diabetes mellitus, with and without considering adjustments for central corneal thickness (CCT). MethodsA total of 98 eyes of 98 patients with open angles were included. Patients were randomly assigned to receive either 0.5% tropicamide (49 eyes) or 1% tropicamide (49 eyes). IOP was measured by Goldmann applanation tonometry. Pupillary diameter and CCT were measured by a Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) before and 30 min after tropicamide administration. ResultsThe mean IOP change was 0.12 ± 1.71 mmHg in the 0.5% tropicamide group and 0.25 ± 1.70 mmHg in the 1% tropicamide group. These two values were not significantly different, even after adjusting IOP for CCT using all formulae (P > 0.05). Without adjustment, the mean post-dilation IOP was similar to the mean pre-dilation IOP in both groups (P > 0.5), and none of the patients experienced an IOP increase of 5 mmHg or more. With adjustment, the mean IOP increased significantly after administration of 0.5% tropicamide, as determined by the Ehlers formula (P = 0.02). Similarly, the mean IOP increased significantly after administration of 1% tropicamide, as determined by the Ehlers formula (P = 0.008), the Doughty formula (P = 0.03), and the Kohlhaas formula (P = 0.04). In each study group, a single patient encountered an increase in IOP ≥5 mmHg when IOP adjustment was performed using the Ehlers formula. ConclusionCycloplegia with 0.5% and 1% tropicamide leads to similar mean changes in IOP in patients with diabetes. However, the statistical significance of the change and the occurrence of the significant increases in IOP, as determined by a predefined cut-off point, are dependent upon the method used to adjust the IOP.

Assessing the Impact of Tropicamide on Anterior Segment Parameters in Diabetic Patients: A Randomized Clinical Trial.

Evaluation of anterior segment parameters is crucial in ophthalmic procedures such as intraocular surgeries and contact lens fitting. However, the use of tropicamide in diabetic patients presents challenges due to its potential impact on biometric measurements. This study aims to investigate and compare the effects of 0.5% and 1% tropicamide on anterior segment parameters in diabetic patients. This double-masked randomized clinical trial enrolled 98 patients with diabetes mellitus. Participants were randomly assigned to receive either 0.5% or 1% tropicamide. Anterior segment parameters were measured using Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) before and 30 minutes after tropicamide administration. Parameters included anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), keratometry, central corneal thickness (CCT), white-to-white distance (WTW), and pupillary diameter (PD). Both concentrations of 0.5% and 1% tropicamide induced significant changes in anterior segment parameters. There was a notable increase in PD (2.99 ± 0.62, 3.11 ± 0.55, respectively, both P-values < 0.001), ACD (both 0.10 ± 0.05, both P-values < 0.001), ACV (16.69 ± 9.56, 17.51 ± 9.26, respectively, both P-values < 0.001), and WTW (0.06 ± 0.14,0.03 ± 0.30, respectively, both P-values < 0.001), along with a decrease in ACA (-3.50 ± 10.65, -3.30 ± 6.87, P-value< 0.001 and P-value=0.001,respectively), and CCT (-6.10 ± 8.06,-6.39 ± 9.97,respectively, both P-values < 0.001) post-dilation. However, no significant changes were observed in keratometry (front Km (-0.03 ± 0.19, -0.04 ± 0.21, respectively), back Km (0.01 ± 0.05, 0.004 ± 0.05, respectively), P-values> 0.05). Both concentrations of tropicamide exhibited comparable effects on anterior segment parameters in diabetic patients. These post-dilation changes should be considered for accurate intraocular lens power calculation and decision-making for cataract, phakic intraocular lens, and refractive surgeries.

Electroretinography, Ocular Ultrasonography, and Phacoemulsification of Bilateral Cataracts in Two Juvenile Loggerhead Sea Turtles (Caretta caretta) of the Mediterranean Region.

Bilateral cataracts were diagnosed in two rescued juvenile, immature loggerhead sea turtles (Caretta caretta), weighing 1.65 and 1.7 kg. Both animals showed vision impairment and difficulty in feeding without assistance. In fact, they did not notice the presence of the food in the tank unless it was brought close to touching the mouth. Ocular ultrasonography and electroretinography showed no lesions of the vitreal body and retinal layer, therefore, both animals were candidates for bilateral cataract surgery. Topical administration of tropicamide + phenylephrine alternating with rocuronium resulted in only minimal mydriasis. Administration of intracameral rocuronium did not improve mydriasis. Phacoemulsification using a one-handed technique was performed bilaterally with a phacoemulsification device (Sovereign, AMO (Abbott Medical Optics®). After surgery, the systemic anti-inflammatory drug (dexamethasone 0.2 mg/kg, IM daily for one week) and antibiotics (enrofloxacin 10 mg/kg IM q 72 h, for 4 weeks; ceftazidime 20 mg/kg IM q 72 h for 3 weeks) were administered. Topical ofloxacin, flurbiprofen and tobramycin/dexamethasone were instilled TID for 4 weeks. Both turtles regained vision in both eyes. Results at a 10-month follow-up were satisfactory. This is the first report of cataracts in turtles rescued in the Mediterranean Sea and the first description of surgical treatment of cataracts in loggerhead turtles so young.

Effect of cyclopentolate versus tropicamide on anterior segment angle parameters in three refractive groups

ABSTRACT Clinical relevance Frequent clinical application of cycloplegia in clinical practice makes it essential to assess how this condition influences anterior segment angle parameters. Background This study aims to compare the effects of cyclopentolate and tropicamide on anterior segment angle parameters in three adult refractive groups. Methods Sixty healthy individuals were recruited and assigned into three refractive groups according to inclusion criteria. At baseline visit, anterior segment angle parameters were measured using anterior segment optical coherence tomography in the right eye. All measurements were repeated at two separate visits, one week apart, after administration of tropicamide 1% and cyclopentolate 1% at similar conditions. Main outcome measures were angle‐opening distance, trabecular iris angle, trabecular iris space area and anterior chamber depth. Anterior segment angle parameters were recorded at temporal areas (180 degrees). Results Sixty participants (29 men and 31 women, age: 27.82 ± 4.71-years) completed the experiment. Baseline mean spherical equivalents were +1.52 ± 1.20 D, −0.04 ± 0.33 D and −1.91 ± 0.91-D in hyperopic, emmetropic and myopic groups, respectively. No statistically significant differences were found between tropicamide and cyclopentolate for all angle parameters in three refractive groups. Both drops induced an increase in all parameters in three refractive groups. Analysis between refractive groups revealed that a more hyperopic refraction was associated with less trabecular iris angle, angle‐opening distance and anterior chamber depth parameters in baseline, after tropicamide and cyclopentolate instillations. Conclusions Topical application of cycloplegic eye drops in healthy individuals leads to small but significant changes in anterior chamber depth and anterior segment angle parameters, regardless of refractive status. Moreover, lower values of anterior chamber depth and anterior segment angle parameters in hyperopic individuals after administration of cycloplegic drops should be taken into account during biometric measurement and phakic intraocular lens implantation. Due to shorter effect and recovery time and less ocular/systemic reaction of tropicamide versus cyclopentolate, tropicamide could be a recommended cycloplegic agent for diagnostic and therapeutic procedures.

Ocular Refraction at Birth and Its Development During the First Year of Life in a Large Cohort of Babies in a Single Center in Northern Italy.

The purpose of this study was to investigate refraction at birth and during the first year of life in a large cohort of babies born in a single center in Northern Italy. We also aimed to analyze refractive errors in relation to the gestational age at birth. An observational ophthalmological assessment was performed within 24 h of birth on 12,427 newborns. Refraction was examined using streak retinoscopy after the administration of tropicamide (1%). Values in the range of between +0.50 ≤ D ≤ +4.00 were defined as physiological refraction at birth. Newborns with refraction values outside of the physiological range were followed up during the first year of life. Comparative analyses were conducted in a subgroup of babies with known gestational ages. The following distribution of refraction at birth was recorded: 88.03% of the babies had physiological refraction, 5.03% had moderate hyperopia, 2.14% had severe hyperopia, 3.4%, had emmetropia, 0.45%, had myopia, 0.94% had astigmatism, and 0.01% had anisometropia. By the end of the first year of life, we observed reductions in hyperopia and astigmatism, and stabilization of myopia. Preterm babies had a four-fold higher risk of congenital myopia and a three-fold higher risk of congenital emmetropia as compared to term babies. Refraction profiles obtained at birth changed during the first year of life, leading to a normalization of the refraction values. Gestational age at birth affected the incidence of refractive errors and amblyopia.

The Pupil Diameter as a Possible Indicator of Neurodegenerative Diseases and Response to Acetylcholinesterase Inhibitors Therapy: In-Depth Measurements Following Topical Administration of Tropicamide and Pilocarpine.

The aim of this study is to assess whether pupillary modifications following ocular anticholinergic and cholinergic drugs can identify subjects with neurodegenerative diseases from early stages. 51 subjects were divided into 3 groups, according to different neurodegenerative diseases, and compared with a control group of 10 patients. Pupil diameter has been measured at different times after topical administration of tropicamide 0.01% in the right eye. Then, topical administration of pilocarpine 0.06% has been performed, followed by pupillary constriction measurement. Pupillary response rates were stratified according to acetylcholinesterase inhibitors intake. Observed mydriasis and pupillary constriction was similar in all study groups at all evaluation times. Patients without acetylcholinesterase inhibitors intake presented greater mydriasis. Although it was not possible to observe significant differences among groups in terms of pupillary response, the analysis of pupillary features may become an useful tool to detect efficacy of acetylcholinesterase inhibitors.

Acute Exacerbation of Fever Following Administration of Tropicamide and Phenylephrine Ophthalmic Solution: A Case Report.

A 24-year-old woman with atopic dermatitis and persistent fever (axillary temperature of 37–38 °C for 6 months) received combination ophthalmic drops containing tropicamide and phenylephrine (Mydrin®-P), which exacerbated her fever within 15 min after instillation. Her axillary fever reached 40.1 °C but resolved the following day. No new dermatological symptoms developed. Although the patient’s fever may have been caused by either tropicamide or phenylephrine, neither of which have been reported to induce fever in topical formulations, atopic dermatitis and tropicamide’s inhibitory effect on perspiration under hot and humid conditions may have been the more probable cause. While drug-induced fever has been reported for other ophthalmic anticholinergic agents, this is the first reported case of possible fever exacerbation by an ophthalmic formulation of tropicamide, if the causative agent is assumed to be tropicamide.

Effects of two concentrations of topical tropicamide on the Schirmer tear test in clinically normal cats.

The aim of this study was to evaluate the effect of topical tropicamide at two concentrations (0.5% and 1.0%) on the Schirmer tear test (STT) results in clinically normal cats. Twenty-four adult domestic shorthair cats were randomly assigned to three groups. In all three groups, ophthalmic solutions were instilled in a randomly selected eye and the opposite eye served as the control. In groups 1, 2 and 3 one drop of 0.5% tropicamide, 1.0% tropicamide and distilled water was used, respectively. Tear production in both eyes was tested 30 and 60 mins after instillation in all three groups. Baseline mean ± SEM STT values for the treated eyes in groups 1, 2 and 3 were 13.37 ± 2.91 mm/min, 10.87 ± 1.39 mm/min and 11.37 ± 1.65 mm/min, respectively. Thirty minutes after the drug instillation in the treated eye, mean ± SEM STT values in groups 1, 2 and 3 were 4.87 ± 3.05 mm/min, 2.00 ± 0.84 mm/min and 11.25 ± 1.81 mm/min, respectively. The mean ± SEM STT levels of the treated eye after 60 mins were 3.75 ± 1.87 mm/min, 0.5 ± 0.37 mm/min and 11.42 ± 1.78 mm/min in groups 1, 2 and 3, respectively. Use of 0.5% topical tropicamide, instead of 1.0% tropicamide, as a mydriatic agent, can be recommended in cats. Tear production measurement should be performed prior to the administration of tropicamide, regardless of the concentration of this drug.

Age-related changes in the atrial muscarinic type 2 receptor and their effects on atrial fibrillation vulnerability in rabbits

Aging plays an important role in increased vulnerability to atrial fibrillation (AF). Mediated by activity at the muscarinic type 2 receptor (M2R), the parasympathetic nerve contributes to the onset of AF. The purpose of this study was to investigate whether aging changes the distribution of M2R in the atrial myocardium and to determine the impact of these changes on AF vulnerability. Expression of M2R in the atrial myocardium was evaluated by immunostaining and Western blot in three groups—young (3 months old), mature (8 months old) and senescent (36–48 months old) rabbits. AF inducibility was recorded with and without cervical vagal stimulation (VS) in vivo in all groups. AF inducibility, the atrial effective refractory period (AERP) and the monophasic action potential (MAP) were recorded in an additional seven senescent rabbits before and after topical administration of tropicamide. The results showed that the density of M2R in the left atrial free wall (LAFW) was significantly higher than that in other parts of the atria. The left atrial appendage had a higher level of M2R expression than the right atrium. The M2R density of the epicardial side was greater than that of endocardial side in both atria. The senescent group had a significant increase in M2R expression in the LAFW relative to the mature group. AF inducibility was also higher in the senescent group than in the other two groups. After tropicamide administration in the senescent rabbits, AF inducibility decreased significantly, the VS-induced decrease in AERP and MAP duration at 90% repolarization (MAPD90) of LAFW was attenuated, and the dispersion of the AERP and MAPD90 increase was attenuated. In conclusion, our results suggested that there is spatial heterogeneity in the M2R distribution in the atria of the rabbit. The density of M2R in the LAFW increased with the aging of rabbits. This change in M2R enhanced the heterogeneity of the M2R distribution and contributed to the change in age-related AF vulnerability.

Chloral Hydrate Anesthesia and Lens Opacification in Mice

Purpose: To study the effect of chloral hydrate in the eye lens in mice. Methods: We instilled tropicamide in the eyes of two groups of eight 129 strain wild-type mice and injected chloral hydrate intraperitoneally (400 mg/kg). A drop of hypromellosum solution was additionally instilled in the eye of the second group to reduce corneal dehydration. The lens was inspected at several time intervals with a standard slit lamp biomicroscope after the injection. Results: No lens opacification was found in any animal after the topical administration of tropicamide. On the contrary, the intraperitoneal administration of chloral hydrate produced lens opacification in both groups of animals. Conclusions: We show that chloral hydrate, when used intraperitoneally, induces acute and reversible lens opacification in all animals. In addition, we found that instillation of hypromellose solution does not prevent the lens opacification caused by chloral hydrate injection. We hypothesized some plausible explanations for these findings.

Mist Delivery of Eye Medication to the Anterior Segment

To compare the mydriatic efficacies of mist and drop delivery of tropicamide 1.0%. Randomized, masked, active, controlled clinical trial. One hundred subjects were randomized to receive small-volume (6 microl) mist administration of tropicamide 1.0% in one eye and either nothing or a conventional drop (30 microl) of the same solution in the fellow eye. Comparing misted eyes with untreated eyes in the same subjects, the mean maximal increase in pupil diameter in the misted eyes was 2.02 mm and was 0.25 mm in the fellow eyes. The difference is statistically significant (P <or= .001) Comparing mist-treated eyes with drop-treated eyes in the same subjects, the mean maximal increase in pupil diameter in the misted eyes was 1.98 mm and was 2.11 mm in the drop-treated eyes. The difference was not statistically significant (P = .051). Small-volume mist and conventional drop delivery of tropicamide 1.0% were shown to be similar in mydriatic effectiveness.

Effects of systemic administration of 0.5% tropicamide on intraocular pressure, pupillary diameter, blood pressure, and heart rate in normal cats

The objective of the study was to determine the effects of systemic 0.5% tropicamide on intraocular pressure (IOP), pupillary diameter (PD), blood pressure, and heart rate (HR) in normal felines with normotensive eyes. Intraocular pressure, PD, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and HR were measured in 18 clinically healthy cats. Each of the previously mentioned parameters was measured every 30 min during the trial period. At T(60), each cat was treated with one to two drops of 0.5% tropicamide ophthalmic solution placed on the dorsal aspect of the tongue. Changes in SBP, DBP, MBP, and HR were evaluated using one-way repeated measures analysis of variance, with time as the repeated factor. IOP and PD were evaluated using two-way repeated measures analysis of variance, with time and side (OD vs. OS) as the repeated factors. P values less than or equal to 0.05 were considered statistically significant. After lingual tropicamide administration, the mean PD at T(60) was 3.53 mm OD and 3.53 mm OS. The mean PD at T(90) was 6.36 mm OD and 6.31 mm OS. The mean PD at T(120) was 8.25 mm OD and 8.19 mm OS. This change in PD from T(60), T(90), and T(120) was statistically significant, demonstrating a linear increase in PD over time after tropicamide application on the tongue (P<0.0001). There was no statistically significant difference in PD when comparing the right to the left pupils (P=0.10). The mean IOP at T(60) was 14 mmHg OD and 12.94 mmHg OS. The mean IOP at T(90) was 14.5 mmHg OD and 14.23 mmHg OS. The mean IOP at T(120) was 14.94 mmHg OD and 14.89 mmHg OS. This change in IOP from T(60), T(90), and T(120) was statistically significant, demonstrating a linear increase in IOP over time after tropicamide application on the tongue (P=0.034). There was no statistically significant difference in IOP when comparing the right eye to the left eye (P=0.28). There were no statistically significant differences in SBP, DBP, MBP, and HR values over time for the duration of the study. We conclude that although lingual application of tropicamide appears to result in systemic absorption, causing significant pupillary dilation and elevations in IOP, systemic effects on SBP, DBP, MBP, and HR were not observed.

Changes in chromatic and achromatic contrast sensitivities following tropicamide administration

To investigate the effects of tropicamide on chromatic and achromatic contrast sensitivities over the physiological range of spatial frequencies. A total of 26 healthy volunteers, with a mean age of 32 years, were examined with and without one drop of 1% tropicamide being administered 30 min previously. On each occasion, acuity and pupil diameter were recorded, and chromatic and achromatic contrast sensitivities were examined using the Sussex Grating Machine. Following tropicamide administration mean pupil diameter increased from 4.1 mm to 7.2 mm (P<0.001), and mean BCVA was reduced by 0.07 LogMar units (P<0.001). Achromatic contrast sensitivity was significantly reduced following tropicamide administration at 2.20 cycles per degree (cpd) (P=0.01), 3.40 cpd (P=0.01), 10 cpd (P=0.04), 17 cpd (P=0.04), and 25 cpd (P<0.01). There was no difference in contrast sensitivity at lower spatial frequencies (0.33 and 0.66 cpd). Chromatic contrast sensitivity was not significantly altered when tested along the red-green and tritan confusion axes. Achromatic contrast sensitivity is significantly reduced following tropicamide administration at intermediate and high spatial frequencies. No significant changes were seen at low spatial frequencies and in chromatic contrast sensitivities.

The effects of topical tropicamide and systemic medetomidine, followed by atipamezole reversal, on pupil size and intraocular pressure in normal dogs.

Twenty normal Golden Retrievers being screeened for eye, hip and elbow diseases were given tropicamide topically and medetomidine systemically. Medetomidine effects were later reversed with systemic atipamezole. Pupil size and intraocular pressure changes were determined. Pupil size increased significantly following tropicamide administration and continued to increase slightly but significantly after medetomidine injection. It was unclear whether the slight increase in pupil size following medetomidine administration was due to continued effect of tropicamide or due to the medetomidine itself. Atipamezole did not influence pupil size. Intraocular pressure (IOP) was not affected by these drugs. Ophthalmic screening examination for inherited disease following tropicamide administration is equally feasible prior to sedation with medetomidine and after reversal with atipamezole, but not during the period of sedation.

Analysis of Variance of Microspheres Blood Flow Measurements in Rabbits

As part of a larger study on the interpretation of angiographically derived hemodynamic parameters, blood flow in several ocular tissues was measured using the radioactively labelled microspheres technique. As an unexpected secondary result, it was found that the microspheres data gave quantitative information on hyperaemic effects in the eye. This is the subject of the present paper.The measurements were made in 13 anaesthetized pigmented rabbits. In each animal, three blood flow measurements were performed at three different ocular perfusion pressures (60–15 mmHg). The perfusion pressures of the experimental eye were varied by changing the intra-ocular pressure. The contra-lateral eye served as a control. Labelled microspheres were used as a non-recirculating blood flow indicator, enabling the estimation of regional blood flows, in this case for the iris, ciliary body, peripheral choroid and peripapillary choroid separately.Using analysis of variance with perfusion pressure as covariate and taking into account the blood flow of the control eye, hyperaemia could be quantified in the experimental eye. Apart from a difference amongst animals, hyperaemia depended on tissue type. The amount of hyperaemia proved to be more pronounced in the anterior part of the eye, iris and ciliary body, and to decrease towards the posterior pole.With regard to the causes of this hyperaemia one could speculate about the invasive handling (anterior eye needles) topical administration of tropicamide, in combination with the general anaesthesia.

Sympathetic nervous system does not mediate reflex pupillary dilation during desflurane anesthesia.

Pupil size is determined by an interaction between the sympathetic and parasympathetic divisions of the autonomic nervous system. Noxious stimulation dilates the pupil in both unanesthetized and anesthetized humans. In the absence of anesthesia, dilation is primarily mediated by the sympathetic nervous system. In contrast, pupillary dilation in cats given barbiturate or cloralose anesthesia is mediated solely by inhibition of the midbrain parasympathetic nucleus. The mechanism by which noxious stimuli dilate pupils during anesthesia in humans remains unknown. Accordingly, the authors tested the hypothesis that the pupillary dilation in response to noxious stimulation during desflurane anesthesia is primarily a parasympathetic reflex. In six volunteers, the alpha-I adrenergic receptors of the iris musculature were blocked by unilateral administration of topical dapiprazole; six other volunteers were given unilateral topical tropicamide to block the muscarinic receptors in the iris. Desflurane anesthesia was subsequently induced in all volunteers. Sympathetic nervous system activation, with reflex dilation of the pupil, was produced by noxious electrical stimulation during 4% and 8% end-tidal desflurane, and by a rapid 4%-to-8% step-up in the desflurane concentration. Pupil diameter and the change in pupil size induced by a light stimulus (light reflex amplitude) were measured with infrared pupillometry. Dapiprazole drops produced a Horner's miosis, but pupils were equally small after induction of anesthesia. Pupillary dilation after noxious stimulation and desflurane step-up was identical in the unblocked and dapiprazole-blocked pupils. After tropicamide administration, the pupil was dilated and the light reflex was completely inhibited. Noxious stimulation nonetheless produced a slight additional dilation. During desflurane anesthesia, pupillary dilation in response to noxious stimulation or desflurane step-up is not mediated by the sympathetic nervous system (as it is in unanesthetized persons). Although inhibition of the pupillo-constrictor nucleus may be the cause of this dilation, the mechanism remains unknown.