Short-term effects of cyclopentolate and tropicamide eye drops on macular choroidal thickness in myopic children.

BACKGROUND: To investigate the short-term effects of cyclopentolate and tropicamide eyedrops on choroidal thickness (ChT) in myopic children using placebo or low-dose atropine eyedrops. METHODS: The analysis included 242 myopic individuals (7-19 years) enrolled in two randomised placebo-controlled clinical trials of low-dose atropine eyedrops. Cycloplegia was induced using either one drop of 1% cyclopentolate (n = 161), two drops of 1% cyclopentolate (n = 32) or two drops of 1% tropicamide (n = 49). ChT measurements were taken using swept-source optical coherence tomography before and 30 min after administering the cycloplegic eye drops. A subset of 51 participants underwent test-retest measurements prior to cycloplegia. RESULTS: Mean changes in subfoveal ChT after two drops of tropicamide and one and two drops of cyclopentolate were -2.5 µm (p = 0.10), -4.3 µm (p < 0.001) and -9.6 µm (p < 0.001), respectively. Subfoveal ChT changes after one and two drops of cyclopentolate were significantly greater than the test-retest changes (test-retest mean change: -3.1 µm; p < 0.05), while the tropicamide group was not significantly different (p = 0.64). Choroidal thinning post-cyclopentolate was not significantly different between atropine and placebo treatment groups (p > 0.05 for all macular locations). The coefficient of repeatability (CoR) in the tropicamide group (range: 8.2-14.4 µm) was similar to test-retest (range: 7.5-12.2 µm), whereas greater CoR values were observed in the cyclopentolate groups (one drop: range: 10.8-15.3 µm; two drops: range: 12.2-24.6 µm). CONCLUSIONS: Cyclopentolate eye drops caused dose-dependent choroidal thinning and increased variation in pre- to post-cycloplegia measurements compared with test-retest variability, whereas tropicamide did not. These findings have practical implications for ChT measurements when cyclopentolate is used, particularly for successive measurements.

The effect of three different mydriatic eye drops on retinal vessel diameters.

PURPOSE: To investigate the effects of topically applied 1% tropicamide, 2.5% phenylephrine and 1% cyclopentolate on retinal vessel calliper (VC) using optical coherence tomography (OCT). METHODS: Patients who came to the ophthalmology clinic for routine examination and whose OCT films were taken before dilatation and after 30 min of last dilatation drop were included in the study. 90 ophthalmologically healthy subjects were divided into 3 groups of 30 subject each according to the application of the drops as follows: Tropicamide group (Group 1), Phenylephrine group (Group 2), Cyclopentolate group (Group 3). The right eyes of the subjects were dilated with drops and the left eyes were taken as the control group. VC of retinal artery and vein passing through an area one-half to one-disc diameter from the optic disc margin were measured from OCT films. The mean of the sum of superior retinal artery (SRA) and inferior retinal artery (IRA) VC and the mean of the sum of superior retinal vein (SRV) and inferior retinal vein (IRV) VC before and after the drop were compared. RESULTS: There was no statistically significant change in the mean sum of SRA and IRA VC and the mean sum of SRV and IRV VC before and after dilatation drops in all three groups. CONCLUSION: Dilatation drops have no statistically significant effect on retinal artery and vein VC.

Effects of atropine and tropicamide on ocular biological parameters in children: a prospective observational study.

BACKGROUND: The effectiveness of cycloplegia in delaying the progression of myopia and its application in refractive examination in children have been extensively studied, but there are still few studies on the effects of atropine/tropicamide on ocular biological parameters. Therefore, the purpose of this study was to explore the effects of atropine/tropicamide on children's ocular biological parameters in different age groups and the differences between them. METHODS: This was a prospective observational study in which all school children were examined for dioptres and ocular biological parameters in the outpatient clinic, and 1% atropine or tropicamide was used for treatment. After examination, we enrolled the patients grouped by age (age from 2 to 12 years treated by atropine, 55 cases; age from 2 to 10 years treated by tropicamide, 70 cases; age from 14 to 17 years treated by tropicamide, 70 cases). The ocular biological parameters of each patient before and after cycloplegia were measured, and the difference and its absolute value were calculated for statistical analysis using an independent-samples t test. RESULTS: We compared the value and the absolute value of the differences in ocular biological parameters before and after cycloplegia in the same age group, and we found that the differences were not statistically significant (P > 0.05). There were significant differences in the corresponding values of AL, K1 and ACD among the different age groups (P < 0.05). Before cycloplegia, there were significant differences in AL, K, K1, K2 and ACD in different age groups (P < 0.05). However, the differences in AL, K, K1, K2 and ACD among different age groups disappeared after cycloplegia (P > 0.05). CONCLUSIONS: This study demonstrated that atropine/tropicamide have different effects on cycloplegia in children of different ages. The effects of atropine/tropicamide on ocular biological parameters should be fully considered when evaluating the refractive state before refractive surgery or mydriasis optometry for children of different ages.

[Ways to solve the problem of cross-reactions during immunochromatographic examination of biological objects]. / Puti resheniya problemy perekrestnykh reaktsii pri provedenii immunokhromatograficheskogo issledovaniya biologicheskikh ob"ektov.

The purpose of this review is to study the causes of cross-reactions of a number of drugs (mebeverine, phenibut, tropicamide, ramipril, metoprolol, phenylephrine, sertraline, chloropyramine and diphenhydramine) during the preliminary stage of laboratory diagnostics by immunochromatographic method and to propose a possible algorithm for solving this problem. Conducting a hair study in order to identify the fact of the use of psychoactive substances will increase the reliability of analytical diagnostics and reduce the likelihood of false positive results of the analysis. The use of a validated method of enzymatic hydrolysis of hair will eliminate unreliable results of the analysis due to the detection of the native molecule of the toxicant, increase the efficiency and accuracy of the diagnostic procedure.

The effect of topical ophthalmic proparacaine, fluorescein, and tropicamide on subsequent bacterial cultures in healthy dogs.

OBJECTIVE: To determine whether tropicamide, fluorescein, and proparacaine applied topically before sample collection affect the quantity or species of bacteria isolated via aerobic culture. ANIMALS STUDIED: 12 female adult research beagle cross-breed dogs. PROCEDURES: A conjunctival swab was taken before and after the sequential application of proparacaine, tropicamide, and fluorescein to the same eye (P/T/F) with a five-minute gap between medications. Paired swabs were submitted for aerobic culture. Bacterial enumeration was performed using the spread plate method. Following a one-week washout period, the procedure was repeated using balanced salt solution (BSS). Following a second one-week washout period, the experiment was repeated using ofloxacin 0.3% solution. Colony counts were compared using one-way ANOVA and Tukey post hoc comparison. Bacterial species reduction was compared using a Friedman rank test and Dunn's method. RESULTS: The bacterial colony count for P/T/F and BSS was significantly higher than the ofloxacin group (p = 0.0052, p = 0.0022). There was no significant difference for colony counts between P/T/F and BSS (p = 0.9295). The most frequently isolated bacteria included: Psychrobacter spp., Staphylococcus spp., Corynebacterium spp., and Streptococcus spp. The bacterial species reduction for P/T/F and BSS was significantly lower than for ofloxacin (p < 0.0001, p = 0.0160). There was no significant difference for species reduction between P/T/F and BSS (p = 0.3749). CONCLUSIONS: The application of proparacaine, tropicamide, and fluorescein did not significantly decrease the amount or species of bacteria isolated from the conjunctiva in this canine population. The application of these solutions prior to ocular swab collection in healthy dogs is unlikely to affect subsequent culture results.

Analysis of pupil size by repeat dilation at shrinkage stage.

PURPOSE: To compare the pupil size of the original mydriasis and repeat mydriasis at the pupil shrinkage stage. METHODS: Randomized prospective study. In total, 60 eyes of 30 patients aged 50-70 with age-related cataracts were included. Pupil sizes were measured by the Sirius system before mydriasis, after the first batch of mydriasis, and after the second batch of mydriasis which was 5 h later. Statistical analysis was performed using MedCalc statistical software version 20.0.3 RESULTS: The pupil size of the second batch of mydriasis 5 h later was smaller than the first batch of mydriasis (3.94 ± 0.88 mm vs 5.12 ± 0.96 mm, P < 0.0001). CONCLUSIONS: Less efficiency repeat mydriasis several hours later compared with original mydriasis in our study suggests that preparation of mydriasis at an appropriate time is necessary for ophthalmological operations. The effect of repeat mydriasis again by tropicamide at the shrinkage stage still needs to be explored.

[Determining the time of intoxication due to non-drug use of tropicamide]. / Opredelenie srokov davnosti intoksikatsii pri nemedikamentoznom primenenii tropikamida.

The study objective is to develop approaches to the retrospective assay of tropicamide in biological fluids and hair. The study was performed using the substance of tropicamide. Sample preparation included hydrolysis with the following enzymes: papain, chymotrypsin, trypsin, chymopsin, and hyaluronidase. Extracts were analyzed using a gas chromatograph with mass selective detection Technologies (USA) 7890 A/5977 MSD. When modeling long-term use of tropicamide, male rats of white and brown natural color, about 6 months old and weighing 200-250 g, were used. Animals were injected with a tropicamide solution in the tail vein for 28 days at a dose of 40 mg/kg of body weight. After 28 days of administration of the tropicamide solution, daily urine and blood were collected, and hair was cut from the back and sides of the animal's body. After another 28 days, hair samples were taken again. Within the first 6 hours after the last tropicamide dose, its blood concentration reached the maximum (191.6 µg/ml) and within 4 days decreased by 10 times; in the urine, within the first 24 hours, tropicamide level decreased from 627.7 to 489.9 µg/ml, then for 2-3 days it remained approximately at the same level. From day 4, the tropicamide concentration significantly decreased, and on days 11-12, it was not detected in the urine. After 4 weeks, the tropicamide content in the hair was at the level of quantification (1.25-2.20 ng/mg) and could be detected only by sample preparation by enzymatic hydrolysis with papain. Thus, the developed and validated methods for the enzymatic hydrolysis of biological fluids and hair allowed retrospective studies of biological fluids and hair with high reliability.

A randomized clinical trial using cyclopentolate and tropicamide to compare cycloplegic refraction in Chinese young adults with dark irises.

BACKGROUND: To evaluate the necessity of cycloplegia for epidemiological studies of refraction in Chinese young adults (aged 17-22 years) with dark irises, and to compare the cycloplegic effects of 1% cyclopentolate and 0.5% tropicamide in them. METHODS: A total of 300 young adults (108 males and 192 females) aged 17 to 22 years (mean 19.03 ± 1.01) were recruited from Tianjin Medical University from November 2019 to January 2020. Participants were randomly divided into two groups. In the cyclopentolate group, two drops of 1% cyclopentolate eye drop were administrated (one drop every 5 min), followed by autorefraction and subjective refraction 30 to 45 min later. In the tropicamide group, four drops of 1% Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) eye drop were given (one drop every 5 min), followed by autorefraction and subjective refraction 20 to 30 min later. The participants and the examiners were masked to the medication. Distance visual acuity, intraocular pressure (IOP), non-cycloplegic and cycloplegic autorefraction (Topcon KR-800, Topcon Co. Tokyo, Japan), non-cycloplegic and cycloplegic subjective refraction and ocular biometry (Lenstar LS-900) were performed. RESULTS: The values of spherical equivalent (SE) and sphere component were significantly different before and after cycloplegia in the cyclopentolate group and the tropicamide group (p < 0.05). The mean difference between noncycloplegic and cycloplegic autorefraction SE was 0.39 D (±0.66 D) in the cyclopentolate group and 0.39 D (±0.34 D) in the tropicamide group. There was no significant difference in the change of SE and sphere component after cycloplegia between the cyclopentolate group and the tropicamide group (p > 0.05). In each group, no significant difference was found between autorefraction and subjective refraction after cycloplegia (p > 0.05). We also found that more positive or less negative cycloplegic refraction was associated with the higher difference in SE in each group. CONCLUSIONS: Cycloplegic refractions were generally more positive or less negative than non-cycloplegic refractions. It is necessary to perform cycloplegia for Chinese young adults with dark irises to obtain accurate refractive errors. We suggest that cycloplegic autorefraction using tropicamide may be considered as a reliable method for epidemiological studies of refraction in Chinese young adults with dark irises. TRIAL REGISTRATION: The study was registered on September 7, 2019 (Registration number: ChiCTR1900025774 ).

Is it necessary to wait several minutes between applications of different topical ophthalmic solutions? A preliminary study with tropicamide eye drops in healthy dogs.

OBJECTIVE: To evaluate the efficacy of topical tropicamide when placed at different time intervals before or after a saline drop. ANIMALS STUDIED: Eight healthy Labrador and golden retriever dogs. PROCEDURES: The effect of 1% tropicamide on pupillary diameter (PD) was measured over 240 min when administered alone (control) and then 1 and 5 min prior to, or following, application of a saline drop, with 1-week washout between each of the five trials. Data were analyzed using repeated-measures ANOVA and Tukey post hoc test. RESULTS: Only 6/110 pairwise comparisons among the 5 trials were statistically significant (p ≤ .035), with post-hoc analysis showing no significant differences (p ≥ .14) between the overall means of all trials. In all five trials, maximal PD was reached 30 min after tropicamide application and maintained until 210 min for 180 min (p = .0005). CONCLUSIONS: Our results suggest that waiting 1 min between applications of different ophthalmic solutions may be sufficient for maximal drug effect. Care should be taken when extrapolating these results to other species and different ophthalmic formulations.

The effects of tropicamide and cyclopentolate hydrochloride on laser flare meter measurements in uveitis patients: a comparative study.

PURPOSE: To investigate the effects of 1% cyclopentolate hydrochloride and 1% tropicamide eye drops on aqueous flare measurements by using the laser flare meter. METHODS: One hundred forty eight eyes of 83 patients with inactive uveitis were enrolled. The patients were randomly assigned to receive either 1% tropicamide (Group 1) or 1% cyclopentolate hydrochloride (Group 2) as the mydriatic agent. Best corrected visual acuity (BCVA), intraocular pressure (IOP), aqueous flare reaction levels measured by laser flare meter device (FM 600, Kowa, Kowa Company Ltd, Nagoya, Japan) before and post dilatation agents were evaluated. RESULTS: Group 1 consisted of 75 eyes and Group 2 consisted of 77 eyes. The mean age of Group 1 patients was 34.85 ± 12.60 (range, 12-64) years; the mean age of Group 2 was 36.92 ± 13.30 (range, 12-70) years (p > 0.05). The mean BCVAs of two groups were 0.16 ± 0.43 (range, 0.00-3.10) logMAR and 0.17 ± 0.42 (range, 0.00-3.10) logMAR, respectively. There were no statistically significant differences between Groups 1 and 2 regarding gender or clinical characteristics (p > 0.05). No significant differences were detected in pre- or post-dilatation values between two groups (p = 0.470, p = 0.998). CONCLUSIONS: As a result, anterior chamber flare values in uveitis patients do not differ significantly between 1% tropicamide and 1% cyclopentolate hydrochloride, and both agents can be safely used for dilatation during examination of patients with uveitis.

The effects of cyclopentolate 1% versus tropicamide 1% on anterior segment angle parameters in three refractive pediatric groups.

PURPOSE: This study aims to assess the effects of topical tropicamide 1% versus cyclopentolate hydrochloride 1% on the main numerical anterior chamber angle parameters using anterior segment optical coherence tomography (AS-OCT) in myopic, emmetropic, and hyperopic pediatric populations. METHODS: One hundred eight healthy and non-amblyopic children were enrolled in this prospective study. The children were assigned into three refractive groups of myopia, emmetropia, and hyperopia for both tropicamide and cyclopentolate administrations. Half of the children in three groups were instilled tropicamide 1%, and the remaining halves were instilled cyclopentolate hydrochloride 1%. AS-OCT measurements of the anterior chamber angle in three groups were performed at the temporal areas of the right eyes under similar conditions at baseline, 30 min after tropicamide, and 45 min after cyclopentolate instillations. Main measurements including the angle-opening distance at 500 µm anterior to the scleral spur (AOD500), trabecular iris space area at 500 µm anterior to the scleral spur (TISA500), and scleral spur angle (SSA) were compared between three refractive groups. RESULTS: The groups were age and gender-matched. The mean baseline spherical equivalents were similar in hyperopia groups of the tropicamide (+2.34 ± 0.44) and cyclopentolate (+2.18 ± 0.32) administrations (p = 0.284), as well as the myopic children administered with tropicamide (-2.68 ± 0.40) and cyclopentolate (-2.74 ± 0.38), (p = 0.406). All baseline measurements of AOD500, TISA500, and SSA measurements were similar in three refractive groups for both tropicamide and cyclopentolate as well as the final measurements and thus measurement changes between two sessions (P > 0.05 for all). Both drops induced an increase of AOD500, TISA500, and SSA measurements in three refractive groups (p < 0.05 for all). CONCLUSIONS: Cycloplegic effects of topical instillations of tropicamide and cyclopentolate lead to a significant increase in anterior chamber angle measurements of AS-OCT. This similar effect of the drops should be considered for proper clinical assessment in children.

Recovery dynamics of multifocal pupillographic objective perimetry from tropicamide dilation.

PURPOSE: To study the pupillary system by combining mydriasis and multifocal pupillographic objective perimetry (mfPOP). In particular, we explored how the dynamics of recovery differ for concurrently measured direct and consensual sensitivity, response delay, and signal-to-noise ratios (SNRs) for binocular mydriasis. METHODS: We recruited 26 normal participants, all with brown irides. The dichoptic mfPOP stimuli concurrently assessed 44-region/eye and both pupils. Two pre-dilation tests were followed by pairs of repeated tests at 1, 2, 4, 6, 8, 12, 24, and 48 h following dilation of both pupils with 1% tropicamide. Three subjects were retested with only the right pupil dilated. Linear models determined the independent effects of mydriasis upon the per-region and pupil measures over time. RESULTS: Post-dilation, the per-region delays initially decreased by 16.3 ± 6.02 ms (mean ± SE) (p < 0.0001, cf. baseline of 471.1 ± 4.36 ms), then increased to slower than baseline by 17.42 ± 5.57 ms after 4 h (p < 0.002), recovering to baseline at 8 h. By comparison, per-region sensitivities (constriction amplitudes) were still reduced by - 6.20 ± 0.70 µm at 8 h (p < 0.0001, cf. baseline of 21.1 ± 0.55 µm), recovered at 24 h, but rebounded at 48 h (p = 0.005). The SNRs for sensitivities and delays both recovered by 8-12 h. Across all the data, sensitivities reduced by 2.67 ± 0.25 µm/decade of age, and delay increased by 15.4 ± 1.98 ms/decade (both p < 0.00001). Data from 3 of the 26 subjects who repeated the testing for monocular dilation found that consensual response sensitivities were larger than direct for 8 h (p < 0.018). CONCLUSIONS: The per-region sensitivities were affected for longer than SNRs or delays. Strong early SNRs indicated proportionately lower pupil noise for larger pupil diameters. Following mydriasis with tropicamide 1%, the constriction amplitude measurements with mfPOP should be considered only after 48 h, but time-to-peak can be measured after 8-12 h.

Effect of Tropicamide on crystalline Lens rise in low-to-moderate myopic eyes.

BACKGROUND: Cycloplegics have been reported to induce changes in the lens thickness. However, the studies of correlation between cycloplegia and the lens position are limited. This study aims to investigate changes in crystalline lens rise (CLR) and other anterior segment parameters after inducing cycloplegia with tropicamide. METHODS: In this consecutive case study, 39 children (20 boys and 19 girls; mean age, 9.51 ± 1.75 years, mean spherical equivalence [SE], - 1.9 ± 1.5 D) with low-to moderate myopia were examined using CASIA 2 both before and after 30 min of administering 5-cycles (each 5 min apart) of 0.5% tropicamide. Measurements included CLR, crystalline lens thickness (CLT), mean radius of curvature of the anterior/posterior surface of the lens (Rf_ave/Rb_ave), anterior chamber depth (ACD), anterior chamber width (ACW), and central corneal thickness (CCT). Correlations of CLT and CLR with ACD, SE, and age were assessed respectively. RESULTS: CLT and CLR decreased significantly after cycloplegia (p < 0.001 and p < 0.001, respectively); whereas CCT, ACD, and Rf_ave increased (p = 0.008, p < 0.001, p < 0.001, respectively). A positive correlation was found between CLR and SE (r = 0.565, p < 0.001). However, a negative correlation between ACD and CLR was found before and after cycloplegia (r = - 0.430, p = 0.006; r = - 0.342, p = 0.035, respectively). CONCLUSIONS: The crystalline lens appeared thinner and moved backward after cycloplegia. ACD increased mainly due to the backward movement of the crystalline lens. These results aid in elucidating the impact of crystalline lens changes during the process of accommodation.

The effect of topical tropicamide and phenylephrine on macular and peripapillary microvasculature: an optical coherence tomography angiography study.

PURPOSE: To evaluate the effect of topical tropicamide 1% and phenylephrine 2.5% instillation on macular and peripapillary microvasculature measurements with optical coherence tomography angiography (OCTA). METHODS: Forty eyes of 40 consecutive healthy adults with no known systemic or ocular disease were recruited for this prospective consecutive case study. After complete ophthalmological examination, all patients underwent OCTA measurements (OptoVue Inc, Freemont, CA, USA) to assess foveal avascular zone (FAZ) area, FAZ perimeter, acircularity index of FAZ, foveal density, vessel density of superficial and deep capillary plexus and peripapillary capillary plexus. 6 × 6 mm macular and 4.5 × 4.5 mm peripapillary OCTA images were undertaken before and 30 min after instillation of tropicamide (20 eyes) or phenylephrine (20 eyes) instillation to the right eye, and these were compared to each other and to fellow control eye. RESULTS: 15 male and 25 female patients with a mean age of 43.3 (18-60) years were recruited for the study. Superficial, deep and peripapillary capillary plexus measurements of tropicamide 1% and phenylephrine 2.5% instilled right eyes and left control eyes were similar before and 30 min after instillation (P > 0.05 for all). FAZ assessment tool variables were also similar before and after instillation (P > 0.05 for all) for both eyes. CONCLUSION: Topical pupillary dilatation with tropicamide 1% and phenylephrine 2.5% did not affect macular and peripapillary OCTA measurements. Follow-up OCTA images in retina and glaucoma patients can be captured with a dilated or undilated pupil which seems not to be affected by tropicamide or phenylephrine.

[The development and validation of the methods for enzymatic hydrolysis for the extraction of toxic compounds from the uncoloured hairs]. / Razrabotka i validatsiia metodiki fermentativnogo gidroliza dlia izolirovaniia toksicheskikh veshchestv iz neokrashennykh volos.

The objective of the present study was the development of the method for the extraction of toxic compounds from the uncoloured hairs with the use of enzymatic hydrolysis by proteolytic enzymes of the toxic compounds comprising the group of pharmaceutical substances present on the uncoloured hairs collected for the forensic medical expertise. The experiments were carried out using laboratory animals, viz. guinea pigs having hair of natural white and black colour and white rats that were given per os a phenobarbital solution and a dimedrol solution as well as daily intravenous injections of tropicamide hydrochloride administered every 28 days. The hair obtained from the experimental animals was subjected to acidic, alkaline, and enzymatic hydrolysis with chymotrypsin, trypsin, and papain. The analysis of the extracted materials was performed using the gas chromatographic technique with mass-selective detection. The results of the study give evidence that the completeness of the extraction of the toxic substances from animal hairs with the use of enzymatic hydrolysis is twice and thrice that of acidic and alkaline hydrolysis respectively. The enzymatic hydrolysis methods developed in the present study are equally efficient using the naturally coloured white and black hairs of the laboratory animals which allows to recommend them for the extraction of poisonous substances from such material. The methods were validated.

Anterior chamber perfusion versus posterior chamber perfusion does not influence measurement of aqueous outflow facility in living mice by constant flow infusion.

Mice are now routinely utilized in studies of aqueous humor outflow dynamics. In particular, conventional aqueous outflow facility (C) is routinely measured via perfusion of the aqueous chamber by a number of laboratories. However, in mouse eyes perfused ex-vivo, values for C are variable depending upon whether the perfusate is introduced into the posterior chamber (PC) versus the anterior chamber (AC). Perfusion via the AC leads to posterior bowing of the iris, and traction on the iris root/scleral spur, which may increase C. Perfusion via the PC does not yield this effect. But the equivalent situation in living mice has not been investigated. We sought to determine whether AC versus PC perfusion of the living mouse eye may lead to different values for C. All experiments were conducted in C57BL/6J mice (all ♀) between the ages of 20 and 30 weeks. Mice were divided into groups of 3-4 animals each. In all groups, both eyes were perfused. C was measured in groups 1 and 2 by constant flow infusion (from a 50 µL microsyringe) via needle placement in the AC, and in the PC, respectively. To investigate the effect of ciliary muscle (CM) tone on C, groups 3 and 4 were perfused live via the AC or PC with tropicamide (muscarinic receptor antagonist) added to the perfusate at a concentration of 100 µM. To investigate immediate effect of euthanasia, groups 5 and 6 were perfused 15-30 min after death via the AC or PC. To investigate the effect of CM tone on C immediately following euthanasia, groups 7 and 8 were perfused 15-30 min after death via the AC or PC with tropicamide added to the perfusate at a concentration of 100 µM. C in Groups 1 (AC perfusion) and 2 (PC perfusion) was computed to be 19.5 ± 0.8 versus 21.0 ± 2.1 nL/min/mmHg, respectively (mean ± SEM, p > 0.4, not significantly different). In live animals in which tropicamide was present in the perfusate, C in Group 3 (AC perfusion) was significantly greater than C in Group 4 (PC perfusion) (22.0 ± 4.0 versus 14.0 ± 2.0 nL/min/mmHg, respectively, p = 0.0021). In animals immediately following death, C in groups 5 (AC perfusion) and 6 (PC perfusion) was computed to be 21.2 ± 2.0 versus 22.8 ± 1.4 nL/min/mmHg, respectively (mean ± SEM, p = 0.1196, not significantly different). In dead animals in which tropicamide was present in the perfusate, C in group 7 (AC perfusion) was greater than C in group 8 (PC perfusion) (20.6 ± 1.4 versus 14.2 ± 2.6 nL/min/mmHg, respectively, p < 0.0001). C in eyes in situ in living mice or euthanized animals within 15-30 min post mortem is not significantly different when measured via AC perfusion or PC perfusion. In eyes of live or freshly euthanized mice, C is greater when measured via AC versus PC perfusion when tropicamide (a mydriatic and cycloplegic agent) is present in the perfusate.

Early signal of diverted use of tropicamide eye drops in France.

AIMS: Tropicamide is a mydriatic drug used as eye-drops for diagnostic or therapeutic purposes. From 2013, a diverted use by intravenous route has been suspected in Eastern Europe in opioids users. To date, no signal of misuse has been identified in France. The aims of this study were to investigate any early signals of a diverted use of tropicamide eye drops and to collect information regarding motives for the misuse and tropicamide-induced effects. METHODS: Information was obtained at three levels: (1) at regional level (Midi-Pyrénées area), from reimbursement data and pharmacists' reports on suspicious requests; (2) at national level: from reimbursement data and prescriptions suggesting possible abuse from the OSIAP (Ordonnances Suspectes, Indicateur d'Abus Possible) survey; and (3) at international level: from VigiBase® reports and Web sources. Beta-blocker eye-drops were used as comparators. RESULTS: In France, in 2014-2015, 17 (0.91%, 95% CI [0.53-1.46%]) falsified prescriptions involving tropicamide were identified in the OSIAP survey (compared with 0%, 95% CI [0-0.19%] for beta-blockers). Moreover, 37 other suspicious prescriptions were presented in 2015 (notified in 2016). In Midi-Pyrénées, seven patients aged 35-49 were reimbursed for 19-45 vials of 10 ml, in a year. Since September 2014, the regional Addictovigilance Centre has received 91 notifications of suspicious requests to obtain tropicamide. In VigiBase® , two cases were identified but none in France. An increased interest in tropicamide-related Internet searches was observed from Russia and Ukraine. CONCLUSIONS: These results represent the first early warnings of a tropicamide diverted use in France. Tropicamide abusers would seek euphoria or hallucinations. The high doses involved in intravenous administration could lead to serious complications.

The effects of topical parasympatholytic drugs on pupil diameter and intraocular pressure in healthy dogs treated with 0.005% latanoprost.

PURPOSE: Prostaglandin analogs induce miosis and lower intraocular pressure (IOP). As pupils of latanoprost-treated eyes may have to be dilated for ophthalmoscopy or intraocular surgery, we studied whether 0.5% tropicamide or 1% atropine alter the effects of 0.005% latanoprost on pupil diameter (PD) and IOP in healthy dogs. METHODS: IOP and PD were measured hourly, 8 AM-4 PM, with the right and left eyes serving as control (CE) and treated (TE) eyes, respectively. Measurements were conducted in ten Labrador retrievers with one-week washout: (i) baseline values, (ii) latanoprost at 8 AM, (iii) tropicamide at 8 AM, (iv) latanoprost at 8 AM and tropicamide at 11 AM, and (v) latanoprost at 8 AM and atropine at 11 AM (n = 4). RESULTS: At 4 PM, TE PD was 5.88 ± 0.59, 3.62 ± 0.66, 6.33 ± 1.00, 5.42 ± 0.57, and 8.12 ± 1.24 mm in sessions 1-5, respectively. TE PD was significantly different between treatment sessions 2, 4, and 5 (P = 0.018, Friedman), being most mydriatic in session 5. At 4 PM, TE IOP was 11.27 ± 2.07, 7.10 ± 1.07, 11.1 ± 2.21, 7.70 ± 1.85, and 8.87 ± 1.42 mm Hg in sessions 1-5, respectively, with no differences between treatment sessions 2, 4, and 5 (P = 0.105, Friedman). CONCLUSIONS: Tropicamide and atropine counteracted latanoprost's miotic effect, with atropine causing significantly larger mydriasis, sufficient for indirect ophthalmoscopy. Neither drug counteracted the hypotensive effect of latanoprost during this study period. Further studies are necessary to evaluate the potential risks in glaucomatous dogs.

Injecting eye-drops: a mini-review on the non-clinical use of tropicamide.

OBJECTIVES: The intravenous (IV) injection of tropicamide for non-clinical purposes is a new and widespread drug trend. The aim of this study is to provide the first literature review on the topic. METHODS: Relevant literature was identified through a search of MEDLINE, Psycinfo, Google Scholar, conference proceedings and select citations. RESULTS: Cases of tropicamide (IV) injection have been reported in Russia, Italy, Turkey and Kazakhstan. This phenomenon is mainly secondary to primary opioid (especially heroin) addiction. Several key factors can be associated with its rapid diffusion: (i) enhancement of the 'positive' effects of heroin; (ii) decrease and delay of heroin withdrawal symptoms; (iii) easy availability; (iv) low costs; (v) fast effects; and (vi) visibility of self-reported experiences on Internet. Acute tropicamide intoxications can lead to anticholinergic syndrome, hyperthermia, tremors and convulsions. Chronic tropicamide-related problems include cardiovascular toxicity, psychosis, renal or liver failures, severe weight loss and infections. Fatalities due to tropicamide IV injection have been reported in non evidence-based/peer-reviewed sources, such as drug fora, websites and media news. CONCLUSIONS: Tropicamide IV injections represent a serious health risk. Specific prevention programmes should be implemented for the general population as well as for the high-risk population of polydrug abusers.