Tropicamide Versus Cyclopentolate for Cycloplegic Refraction in Pediatric Patients With Brown Irides: A Randomized Clinical Trial.

PURPOSE: To compare the final cycloplegic refraction of tropicamide 1% and cyclopentolate 1% in children 3-16 years of age with brown irides. DESIGN: Randomized, controlled, multicenter prospective clinical trial. METHODS: Included patients were randomized to either cyclopentolate 1% or tropicamide 1% in the first visit with autorefraction measurements. Each subject underwent a second cycloplegic refraction using the other agent on a separate visit with a minimum of 1-week interval and a maximum of 12 weeks. We measured the change in SE (ΔSE) for each eye by deducting the SE before cycloplegia from the SE after cycloplegia. RESULTS: A total of 185 eyes from 94 children aged 3-16 years (average= 8.79 ±3.11 years) were included. The average SE of both eyes before cycloplegia was -0.082 ± 4.8 diopters. The SE after instillation of cyclopentolate and tropicamide in both eyes was 1.07±5.2 and 0.96±5.1, respectively (P value < .001). The average ΔSE after cycloplegia was 1.15±1.2 for cyclopentolate and 1.04±1.2 for tropicamide (P value < .001). The difference between ΔSE of cyclopentolate and tropicamide was found statistically significant at 0.11±1.2 (P < .001), although clinically insignificant. The ΔSE between the 2 drops before and after cycloplegia in both eyes for all refractive error groups was clinically insignificant. The greatest effect of cyclopentolate and tropicamide was in hyperopic eyes with ΔSE of 1.54±1.4 and 1.39±1.4, respectively. CONCLUSIONS: Tropicamide might be an effective and safe replacement for cyclopentolate in the refracting nonstrabismic pediatric population 3-16 years of age regardless of their refractive error status.

Low dose or very low dose phenylephrine and cyclopentolate microdrops for retinopathy of prematurity eye examinations (The Little Eye Drop Study): a randomised controlled non-inferiority trial.

OBJECTIVE: To determine if very low dose (VLD, 0.5% phenylephrine, 0.1% cyclopentolate) mydriatic microdrop (approximately 7 µL) administration (up to three doses) is non-inferior to low dose (LD, 1% phenylephrine, 0.2% cyclopentolate) mydriatic microdrop administration for ophthalmologist-determined successful retinopathy of prematurity eye examination (ROPEE). DESIGN: Multicentre, prospective, randomised controlled, non-inferiority clinical trial. SETTING: Four neonatal intensive care units in Aotearoa, New Zealand from October 2019 to September 2021. PATIENTS: Infants with a birth weight less than 1250 g or gestational age less than 30+6 weeks and who required a ROPEE. INTERVENTIONS: The intervention: microdrop (approximately 7 µL) of VLD (0.5% phenylephrine and 0.1% cyclopentolate) to both eyes, or the comparison: microdrop of LD (1% phenylephrine and 0.2% cyclopentolate) to both eyes. Up to three doses could be administered. MAIN OUTCOME MEASURES: The primary outcome measure was an ophthalmologist-determined successful ROPEE. RESULTS: One hundred and fifty preterm infants (LD mean GA=27.4±1.8 weeks, mean birth weight=1011±290 g, VLD mean GA=27.5±1.9 weeks, mean birth weight=1049±281 g,) were randomised. Non-inferiority for successful ROPEE was demonstrated for the VLD group compared with the LD group (VLD successful ROPEE=100%, LD successful ROPEE=100%, 95% CI no continuity correction -0.05 to 0.05) and for Maori (95% CI no continuity correction -0.02 to 0.19). CONCLUSION: VLD microdrops enable safe and effective screening for ROPEE in both Maori and non-Maori preterm infants. TRIAL REGISTRATION NUMBER: ACTRN12619000795190.

Effect of topical cyclopentolate alone or combined with phenylephrine in healthy horses.

OBJECTIVE: Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT-1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). ANIMAL STUDIED: Six healthy mares. PROCEDURES: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT-1, IOP, and PD were recorded. RESULTS: The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p < .0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. CONCLUSIONS: Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses' eyes, and do not affect STT-1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses.

The effects of pharmacological accommodation and cycloplegia on axial length and choroidal thickness.

PURPOSE: To investigate the effects of pharmacological accommodation and cycloplegia on ocular measurements. METHODS: Thirty-three healthy subjects [mean (±SD) age, 32.97 (±5.21) years] volunteered to participate in the study. Measurement of the axial length, macular and choroidal thickness, refractive error, and corneal topography, as well as anterior segment imaging, were performed. After these procedures, pharmacological accommodation was induced by applying pilocarpine eye drops (pilocarpine hydrochloride 2%), and the measurements were repeated. The measurements were repeated again after full cycloplegia was induced using cyclopentolate eye drops (cyclopentolate hydrochloride 1%). The correlations between the measurements were evaluated. RESULTS: A significant increase in subfoveal choroidal thickness after applying 2% pilocarpine was identified (without the drops, 319.36 ± 90.08 µm; with pilocarpine instillation, 341.60 ± 99.19 µm; with cyclopentolate instillation, 318.36 ± 103.0 µm; p<0.001). A significant increase in the axial length was also detected (without the drops, 23.26 ± 0.83 mm; with pilocarpine instillation, 23.29 ± 0.84 mm; with cyclopentolate instillation, 23.27 ± 0.84 mm; p=0.003). Comparing pharmacological accommodation and cycloplegia revealed a significant difference in central macular thickness (with pilocarpine instillation, 262.27 ± 19.34 µm; with cyclopentolate instillation, 265.93 ± 17.91 µm; p=0.016). Pilocarpine-related miosis (p<0.001) and myopic shift (p<0.001) were more severe in blue eyes vs. brown eyes. CONCLUSION: Pharmacological accommodation may change ocular measurements, such as choroidal thickness and axial length. This condition should be considered when performing ocular measurements, such as intraocular lens power calculations.

Effects of topical 1% cyclopentolate hydrochloride on quantitative pupillometry measurements, tear production and intraocular pressure in healthy horses.

OBJECTIVE: To evaluate the effect of topical cyclopentolate hydrochloride (CH) on quantitative pupillometric readings (PR), tear production (TP), and intraocular pressure (IOP) in healthy horses. ANIMALS STUDIED: Fourteen client-owned horses. PROCEDURES: In a two-phase design study, each animal received 1% CH ophthalmic solution in the left eye [treated] and 0.9% NaCl in the right eye [control] (0.2 mL each). In the first phase (n = 7), TP, IOP, and PR assessment was performed by Schirmer tear test I, rebound tonometry and static pupillometry, at 1, 8, 24, 48, 72, 96, 120, 148, 172, and 196-hours post-instillation. In the second phase (n = 7), plateau mydriasis was evaluated by assessing PR hourly for 8 hours post-instillation. For PR assessment, pupil area (PA), vertical diameter (VPD), and horizontal diameter (HPD) were recorded. All pupillometries were obtained in a room with fixed light intensity (45-60 lux). Statistical analysis was performed by generalized estimating equations method for the effect on parameters over time. RESULTS: After topical CH, significant differences in pupil dilation were seen from 1 to 172 hours for VPD and from 8 to 24 hours for PA, without significant differences on HPD over time. In the second phase, plateau PA and VPD were reached at 3 hours, while plateau HPD at 2 hours. No significant effects were detected on TP and IOP in both eyes at any time, nor on PR of the nontreated eyes. CONCLUSIONS: Topical 1% cyclopentolate hydrochloride could be considered an effective and safe option when a mydriatic/cycloplegic drug is needed in horses.

Changes in intraocular pressure, horizontal pupil diameter, and tear production during the use of topical 1% cyclopentolate in cats and rabbits.

Background: Cyclopentolate is not commonly used as mydriatic drug in veterinary medicine because of limited data on the local and systemic effects in animals. Aim: To determine the effects of topical 1% cyclopentolate hydrochloride on intraocular pressure (IOP), horizontal pupil diameter (HPD) and tear production in the cat and rabbit's eye during the first hour and up to 36 hours after treatment. Methods: One drop of 1% cyclopentolate hydrochloride was used in the left eye in 10 clinically and ophthalmologically healthy domestic cats and 10 rabbits. IOP and HPD were recorded every 5 minutes during the first hour, then every 2 hours during the following 12-hour period, and at 24 and 36 hours after application. Schirmer tear test (STT) was measured at 30 and 60 minute after treatment, then in same time points as IOP and HPD. Rebound tonometer (TonoVet®) was used to assess IOP, Jameson calliper to measure HPD and STT to determine the tear production. Results: 1% cyclopentolate increased IOP in cats, reaching a maximum (28.1 ± 5.4 mmHg) at T50 and in rabbits at T25 (16.7 ± 1.3 mmHg). Maximal mydriasis in cats was observed at T40 and lasted 24-36 hours, but in rabbits at T25, and returned to pre-treatment values at T10h-T12h. In cats, STT decreased in both eyes 30 minutes after treatment and remained lower throughout the 36-hour period. In rabbits, STT decreased in the treated eye 30 minutes after treatment, but all following STT measurements returned to normal pre-treatment levels. Conclusion: Study showed novel data about the effects of 1% cyclopentolate to IOP, HPD, STT in cats and rabbits. Cyclopentolate in cats caused mydriasis 20-40 minutes after the treatment by increasing IOP, at the same time, pupil diameter reached pre-treatment values 24-36 hours after treatment. In rabbit's mydriasis occurred faster, 10-25 minutes after treatment without significant IOP increase and mydriasis lasted 10-12 hours. Significant STT decrease was recorded in cats, but more likely were connected to stress factors. This drug could be considered as a therapeutical alternative in rabbit more than in cats.

Comparison of cyclopentolate versus tropicamide cycloplegia: A systematic review and meta-analysis / Comparación de la cicloplejia con Ciclopentolato y Tropicamida: revisión sistemática y meta-análisis

Purpose: The aim of the present meta-analysis is to compare the efficacy of cyclopentolate and tropicamide in controlling accommodation during refraction. Methods: A comprehensive literature search was performed in PubMed, Scopus, Science direct and Ovid databases by the key words: "tropicamide"; "cyclopentolate"; "cycloplegia" and "cycloplegic" from inception to April 2016. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2; Biostat Inc., USA). Results: The present meta-analysis included six studies (three randomized controlled trials and three case-control studies). Pooled standardized difference in the mean changes in the refractive error was 0.175 D [lower and upper limits: -0.089; 0.438] more plus in the cyclopentolate group compared to the tropicamide group; however, this difference was not statistically significant (p = 0.194; Cochrane Q value = 171.72 (p < 0.05); I2 = 95.34%). Egger's regression intercept was -5.33 (p = 0.170). Considering type of refractive errors; refractive assessment procedure and age group; although cycloplegic effect of cyclopentolate was stronger than tropicamide; however, this effect was only statistically significant in children; hyperopic patients and with retinoscopy. Conclusion: We suggest that tropicamide may be considered as a viable substitute for cyclopentolate due to its rapid onset of action. Although these results should be used cautiously in infants and in patients with high hyperopia or strabismus when using tropicamide as the sole cycloplegic agent especially in situations that the findings are variable or there is no consistency between the examination results and clinical manifestations of the visual problems

Objetivo: El objetivo del presente meta-análisis es comparar la eficacia de ciclopentolato y tropicamida a la hora de controlar la acomodación durante la refracción. Métodos: Se realizó una búsqueda amplia en la literatura en las bases de datos de PubMed, Scopus, Science direct y Ovid, utilizando las palabras clave: "tropicamida", "ciclopentolato", "cicloplejia" y "ciclopléjico" desde sus inicios a Abril de 2016. La calidad metodológica de la literatura se evaluó con arreglo a Oxford Center for Evidence Based Medicine y la escala Newcastle-Ottawa modificada. Los análisis estadísticos se realizaron utilizando el software Comprehensive Meta-Analysis (versión 2, Biostat Inc., EEUU). Resultados: El presente meta-análisis incluyó seis estudios (tres ensayos controlados aleatorizados y tres estudios de casos-control). La diferencia estandarizada combinada de los cambios medios del error refractivo fue de 0,175 D [límites inferior y superior: -0,089, 0,438], más acusada en el grupo ciclopentolato con respecto al grupo tropicamida aunque, sin embargo, esta diferencia no fue estadísticamente significativa (p = 0,194, Valor Q de Cochrane = 171,72 (p < 0,05), I2 = 95,34%). El valor del intercepto de regresión de Egger fue de -5,33 (p = 0,17). Considerando el tipo de errores refractivos, el procedimiento de valoración refractiva y el grupo de edad, aunque el efecto ciclopléjico de ciclopentolato fue más fuerte que el de tropicamida, dicho efecto fue únicamente significativo en niños, pacientes hipermétropes, y con retinoscopia. Conclusión: Sugerimos la consideración de tropicamida como sustituto viable de ciclopentolato, debido a su rápido inicio de acción. Aunque estos resultados deberían utilizarse con precaución en niños y en pacientes con elevada hipermetropía o estrabismo al utilizar tropicamida como único agente ciclopléjico, especialmente en situaciones en las que los hallazgos sean variables, o no exista consistencia entre los resultados del examen y las manifestaciones clínicas de los problemas visuales

Comparison of the Effect of Cycloplegia on Astigmatism Measurements in a Pediatric Amblyopic Population: A Prospective Study.

PURPOSE: To study the effect of cycloplegia on astigmatism measurements in pediatric patients with amblyopia. METHODS: This was a prospective comparative clinical study. Participants 4 to 17 years old were recruited from the patient population at the Arkansas Children's Hospital eye clinic after informed consent was obtained. Autorefractor measurements were used to obtain values of refractive error in amblyopic and non-amblyopic patients before and after cycloplegia. The groups were subdivided into myopia and hyperopia and with and without underlying amblyopia. The refractive error was expressed as sphere, cylinder, axis of astigmatism, and spherical equivalent. The treatment effect was summarized as the mean difference (95% confidence interval) for each outcome. RESULTS: No statistically significant difference was found on the axis and power of astigmatism before and after cycloplegia in the patients with amblyopia (P = .28 and .99, respectively). CONCLUSIONS: Non-cycloplegic autorefraction measurements may be considered safe for refining astigmatism power and axis in pediatric patients with amblyopia. [J Pediatr Ophthalmol Strabismus. 2018;55(5):293-298.].

[The distribution of 2-(dimethylamino)ethyl-(1-hydroxycyclopentyl)(phenyl)acetate in the organism of the warm-blooded animals after its intra-gastric administration]. / Raspredelenie 2-(dimetilamino)étil-(1-gidroksitsiklopentil)(fenil)atsetata v organizme teplokrovnykh zhivotnykh pri vnutrizheludochnom vvedenii.

The objective of the present study was to elucidate the distribution of 2-(dimethylamino)ethyl-(1-hydroxycyclopentyl)(phenyl)acetate in the organism of the warm-blooded animals after its intra-gastric administration. The methods applied in the study included thin layer chromatography in silicagel, aci-nitroprosalt staining reaction, UV-spectrophotometry,, and GC-mass spectrometry. The identification and the quantitation of 2-(dimethylamino)ethyl-(1-hydroxycyclopentyl)(phenyl)acetate in the organs and blood of the warm-blooded animals were carried out within 20, 150, and 360 min after a single intra-gastric administration of 1300 ml of this poisonous substance. It was shown that the largest amounts of 2-(dimethylamino)ethyl-(1-hydrpxycyclopentyl)(phenyl)acetate at the above time-points were present in the tissue of the stomach and small intestine, brain, muscles, spleen, and lungs of the animals.

Glyoxalase 1 (GLO1) Inhibition or Genetic Overexpression Does Not Alter Ethanol's Locomotor Effects: Implications for GLO1 as a Therapeutic Target in Alcohol Use Disorders.

BACKGROUND: Glyoxalase 1 (GLO1) is an enzyme that metabolizes methylglyoxal (MG), which is a competitive partial agonist at GABAA receptors. Inhibition of GLO1 increases concentrations of MG in the brain and decreases binge-like ethanol (EtOH) drinking. This study assessed whether inhibition of GLO1, or genetic overexpression of Glo1, would also alter the locomotor effects of EtOH, which might explain reduced EtOH consumption following GLO1 inhibition. We used the prototypical GABAA receptor agonist muscimol as a positive control. METHODS: Male C57BL/6J mice were pretreated with either the GLO1 inhibitor S-bromobenzylglutathione cyclopentyl diester (pBBG; 7.5 mg/kg; Experiment 1) or muscimol (0.75 mg/kg; Experiment 2), or their corresponding vehicle. We then determined whether locomotor response to a range of EtOH doses (0, 0.5, 1.0, 1.5, 2.0, and 2.5) was altered by either pBBG or muscimol pretreatment. We also examined the locomotor response to a range of EtOH doses in FVB/NJ wild-type and transgenic Glo1 overexpressing mice (Experiment 3). Anxiety-like behavior (time spent in the center of the open field) was assessed in all 3 experiments. RESULTS: The EtOH dose-response curve was not altered by pretreatment with pBBG or by transgenic overexpression of Glo1. In contrast, muscimol blunted locomotor stimulation at low EtOH doses and potentiated locomotor sedation at higher EtOH doses. No drug or genotype differences were seen in anxiety-like behavior after EtOH treatment. CONCLUSIONS: The dose of pBBG used in this study is within the effective range shown previously to reduce EtOH drinking. Glo1 overexpression has been previously shown to increase EtOH drinking. However, neither manipulation altered the dose-response curve for EtOH's locomotor effects, whereas muscimol appeared to enhance the locomotor sedative effects of EtOH. The present data demonstrate that reduced EtOH drinking caused by GLO1 inhibition is not due to potentiation of EtOH's stimulant or depressant effects.

Higher-Order Aberrations After Cyclopentolate, Tropicamide, and Artificial Tear Drops Application in Normal Eyes.

PURPOSE: To determine the effect of cyclopentolate, tropicamide, and artificial tear drops on higher-order aberrations (HOAs) in normal eyes with OPD-Scan III (Nidek Inc., Tokyo, Japan). METHODS: In this study, 189 eyes of individuals aged 20 to 35 years were selected as samples. Inclusion criteria were a corrected visual acuity of 20/20 or better, a minimum size of about 5 mm for the pupil in the dark, hyperopia and myopia less than 5 D, and astigmatism less than 2 D. Moreover, participants with pathological eye problems, a history of intraocular surgery, and ocular diseases affecting the accommodation, pupil size, and corneal surface were excluded. Higher-order aberrations of the participants were assessed by the OPD-Scan III before and after cyclopentolate (Colircuss), tropicamide (Mydrax 0.5%), and artificial tears (Tearlose) drop instillation. RESULTS: After instilling cyclopentolate drops, the mean of the total root mean square (RMS) increased from 4.580 to 6.335 D, total spherical aberration increased from 0.155 to 0.381 D, and total coma increased from 0.195 to 0.369 D; the increases were significant for total RMS and total spherical aberration, but a significant relationship was not seen with total coma. After tropicamide, the mean aberrations of total RMS increased from 4.301 to 4.568 D, total spherical aberration increased from 0.146 to 0.160 D, and total coma increased from 0.213 to 0.230 D; the increase was only significant for total coma. On the other hand, after artificial tears, the average of all aberrations decreased in a nonsignificant manner. CONCLUSION: Most changes of mean aberrations were related to cyclopentolate drops. Tropicamide and artificial tears had the second and third rank according to their effect on mean errors. As a result, it seems that ocular accommodation is the most important impact on HOA than pupil size. However, the pupil size is the second factor for HOAs.

Comparison of cyclopentolate versus tropicamide cycloplegia: A systematic review and meta-analysis.

PURPOSE: The aim of the present meta-analysis is to compare the efficacy of cyclopentolate and tropicamide in controlling accommodation during refraction. METHODS: A comprehensive literature search was performed in PubMed, Scopus, Science direct and Ovid databases by the key words: "tropicamide"; "cyclopentolate"; "cycloplegia" and "cycloplegic" from inception to April 2016. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2; Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (three randomized controlled trials and three case-control studies). Pooled standardized difference in the mean changes in the refractive error was 0.175 D [lower and upper limits: -0.089; 0.438] more plus in the cyclopentolate group compared to the tropicamide group; however, this difference was not statistically significant (p=0.194; Cochrane Q value=171.72 (p<0.05); I2=95.34%). Egger's regression intercept was -5.33 (p=0.170). Considering type of refractive errors; refractive assessment procedure and age group; although cycloplegic effect of cyclopentolate was stronger than tropicamide; however, this effect was only statistically significant in children; hyperopic patients and with retinoscopy. CONCLUSION: We suggest that tropicamide may be considered as a viable substitute for cyclopentolate due to its rapid onset of action. Although these results should be used cautiously in infants and in patients with high hyperopia or strabismus when using tropicamide as the sole cycloplegic agent especially in situations that the findings are variable or there is no consistency between the examination results and clinical manifestations of the visual problems.

Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.

PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 µm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 µm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 µm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.

[The effects of cycloplegic eyedrops on corneal tomography]. / Effets des gouttes cycloplégiques sur la tomographie cornéenne.

PURPOSE: Whether cycloplegics affect standard keratorefractometric and tomographic measurements is unknown. The purpose of our study was to compare the effects of cycloplegics (cyclopentolate and atropine) on corneal shape and refractive power of the eye. METHODS: This study was performed on 84 eyes of 49 study participants. Patients were randomized into two groups: atropine 1% (32 eyes) and cyclopentolate 1% (52 eyes). Corneal tomography was performed with the Orbscan IIz. To evaluate the corneal shape, simulated keratometry values, anterior and posterior best-fit sphere, white-to-white and tangential and axial corneal power were performed for the anterior and posterior corneal surfaces before and during cycloplegia. Pupil diameter, anterior chamber depth, corneal thickness at the 3, 5 and 7mm optical zones, thinnest area of the cornea and corneal thickness at the visual axis were examined. Data were analyzed using an SPSS statistical package. RESULTS: The anterior and posterior BFS (in the atropine 1% group, anterior BFS was P=0.188; anterior BFS in the cyclopentolate group was P=0.227) and tangential and axial corneal power showed no change during cycloplegia in either group. SimK showed no statistical significance. The ACD was deeper when using atropine than cyclopentolate. Corneal thickness remained unchanged during cycloplegia in both groups. Pupil diameter was larger in light-colored irides in the cyclopentolate group than the atropine group. There was no change in W to W before (P=0.473) and during cycloplegia (P=0.287) in either group. CONCLUSIONS: Our results suggest that usage of atropine or cyclopentolate does not alter corneal shape.

The effect of topical anti-muscarinic agents on subfoveal choroidal thickness in healthy adults.

PurposeTo investigate the effects of tropicamide and cyclopentolate, which are two anti-muscarinic agents commonly used in the ophthalmologic practice, on subfoveal choroidal choroidal thickness (ChT) in healthy adults.MethodsA total of 74 healthy adult subjects were enrolled in the study. Subjects were randomly divided into two groups: (1) cyclopentolate group (n=37) in which the right eye (study eye) of each subject received topical cyclopentolate 1%, and the fellow eye (control eye) received artificial tears and (2) tropicamide group (n=37) in which the right eye (study eye) of each subject received topical tropicamide 1% and the fellow eye (control eye) received artificial tears. Each topical medication was applied three times with 10-min intervals. ChT measurements were performed at baseline and 40 min after the last drops of the topical medications by enhanced depth imaging (EDI) optical coherence tomography (OCT).ResultsIn the cyclopentolate group, subfoveal ChT significantly increased in the study eyes (P=0.013), whereas it did not significantly change in the control eyes (P=0.417). On the other hand, in the tropicamide group, no significant subfoveal ChT changes were observed in either the study eyes (P=0.715) or the control eyes (P=0.344).ConclusionsThe current study demonstrated that cyclopentolate caused significant choroidal thickening, whereas tropicamide had no significant effect on ChT in healthy adults. As a result, mydriasis by cyclopentolate may complicate ChT measurements by EDI OCT. Use of tropicamide may provide more reliable results for evaluation of ChT in ocular pathologies.

Effect of topical 1% cyclopentolate hydrochloride on tear production, pupil size, and intraocular pressure in healthy Beagles.

OBJECTIVE: The objective of the study was to evaluate the effect of topical 1% cyclopentolate hydrochloride (CH) on tear production (TP), pupil size (PS), and intraocular pressure (IOP) in dogs. ANIMAL STUDIED: Fifteen healthy beagle dogs from the UAB research-teaching colony. PROCEDURE: Dogs without ocular diseases were included. Each animal received one drop of 1% CH ophthalmic solution in a randomly selected eye. TP, PS, and IOP were evaluated by means of STT-1, static pupillometry, and rebound tonometry, respectively. Evaluations were performed before drug instillation and at 0.5, 1, 2, 4, 8, 12, 24, 30, 36, 48, 54, 60, 72, 84, and 96 h postinstillation. Examinations took place in a room with fixed light intensity (40-55 lux). Statistical analysis was performed by means of generalized estimating equations for the effect on STT-1, pupil size, and IOP over time. RESULTS: After unilateral application of 1% CH, significant pupillary dilation started at 30 min, reached its maximum at 12 h, and returned to pre-instillation size after 72 h. No significant effects were found on TP or IOP, at any time. No effects were observed in the untreated eye on any of the parameters evaluated. CONCLUSION: Cyclopentolate hydrochloride could be considered a therapeutic alternative when use of a cycloplegic drug is needed and effects on tear production and IOP are unwanted.

The effect of pupil dilation on AL-Scan biometric parameters.

The purpose of this study was to investigate the effects of pupil dilation on the parameters of the AL-Scan (Nidek Co., Ltd, Gamagori, Japan). We compared the measurements of axial length (AL), anterior chamber depth (ACD), central corneal keratometry reading, pupil diameter, and intraocular lens (IOL) power of 72 eyes of 72 healthy volunteers and patients scheduled for cataract surgery before and 45 min after instillation of cyclopentolate hydrochloride 1 % using the AL-Scan. Intraobserver repeatability was assessed by taking three consecutive recordings of ACD and AL. Only ACD readings were significantly different between predilation and postdilation (P < 0.001). The difference of the other measurements between two sessions was not statistically significant (P > 0.001). Only two cases in the study demonstrated changes in IOL power higher than 0.5 D. The intraobserver repeatability of both devices was good (CV values for ACD and AL were 0.16 and 0.20 %, respectively). Dilated pupil size did not affect the measurement of IOL power using the A-Scan optical biometer, but increase in ACD after dilation should be taken into account when performing refractive surgeries in which ACD is very important such as phakic anterior chamber IOL implantation.

Effect of cycloplegia on the refractive status of children: the Shandong children eye study.

PURPOSE: To determine the effect of 1% cyclopentolate on the refractive status of children aged 4 to 18 years. METHODS: Using a random cluster sampling in a cross-sectional school-based study design, children with an age of 4-18 years were selected from kindergardens, primary schools, junior and senior high schools in a rural county and a city. Auto-refractometry was performed before and after inducing cycloplegia which was achieved by 1% cyclopentolate eye drops. RESULTS: Out of 6364 eligible children, data of 5999 (94.3%) children were included in the statistical analysis. Mean age was 10.0±3.3 years (range: 4-18 years). Mean difference between cycloplegic and non-cycloplegic refractive error (DIFF) was 0.78±0.79D (median: 0.50D; range: -1.00D to +10.75D). In univariate analysis, DIFF decreased significantly with older age (P<0.001;correlation coefficient r:-0.24), more hyperopic non-cycloplegic refractive error (P<0.001;r = 0.13) and more hyperopic cycloplegic refractive error (P<0.001;r = 0.49). In multivariate analysis, higher DIFF was associated with higher cycloplegic refractive error (P<0.001; standardized regression coefficient beta:0.50; regression coefficient B: 0.19; 95% confidence interval (CI): 0.18, 0.20), followed by lower intraocular pressure (P<0.001; beta: -0.06; B: -0.02; 95%CI: -0.03, -0.01), rural region of habitation (P = 0.001; beta: -0.04; B: -0.07; 95%CI: -0.11, -0.03), and, to a minor degree, with age (P = 0.006; beta: 0.04; B: 0.009; 95%CI: 0.003, 0.016). 66.4% of all eyes with non-cycloplegic myopia (≤-0.50D) remained myopic after cycloplegia while the remaining 33.6% of eyes became emmetropic (18.0%) or hyperopic (15.7%) under cycloplegia. Prevalence of emmetropia decreased from 37.5% before cycloplegia to 19.8% after cycloplegia while the remaining eyes became hyperopic under cycloplegia. CONCLUSIONS: The error committed by using non-cycloplegic versus cycloplegic refractometry in children with mid to dark-brown iris color decreased with older age, and in parallel manner, with more myopic cycloplegic refractive error. Non-cycloplegic refractometric measures lead to a misclassification of refractive error in a significant proportion of children.

Effects of muscarinic receptor modulators on ocular biometry of guinea pigs.

PURPOSE: This study investigated whether pilocarpine and cyclopentolate induce changes in ocular biometry of guinea pigs, in order to understand if guinea pigs have a similar response to these two agents as humans do. METHODS: Under general anaesthesia, refraction, axial components and surface curvature in various optical interfaces of the eye were measured in 10 guinea pigs (age of 2 weeks) at baseline (0 min) and different time points (5, 10, 20, 30, 60, 90 min) after topical administration of pilocarpine or cyclopentolate. The interval between the two drug treatments for the same animals was at least 24 h. RESULTS: Eyes treated with pilocarpine developed approximately 6D myopia (p < 0.001 from 0 to 90 min) with a decrease in anterior lens radius of curvature (ALRC) (p < 0.001 from 0 to 90 min, repeated measures anova). This myopic shift was moderately correlated to the decreased ALRC (r(2)  = 0.48, p < 0.001). Furthermore, a small but significant increase in the VCD (p < 0.001 from 0 to 30 min, repeated measures anova) with an unchanged AL (p = 0.85 from 0 to 90 min, repeated measures anova) after the drug treatment suggested a transient and mild forward movement of the lens. Cyclopentolate dilated the pupil in all eyes (p < 0.001 from 0 to 90 min, repeated measures anova) but did not change other ocular parameters. CONCLUSIONS: The muscarinic agonist, pilocarpine induced a myopic shift mainly due to a decrease in ALRC, suggesting that guinea pigs have an accommodative mechanism similar to that in humans. The minimal changes produced by cyclopentolate could be due to the use of general anaesthesia, which may have reduced the susceptibility of the eye to topical cyclopentolate in the induction of cycloplegia.

Effects of 1% cyclopentolate hydrochloride on anterior segment parameters obtained with Pentacam in young adults.

PURPOSE: To investigate the effects of topically applied 1% cyclopentolate hydrochloride on anterior segment parameters obtained with a Pentacam rotating Scheimpflug camera in healthy young adults. METHODS: Anterior segment analyses of 25 eyes from 25 young adults (Group 1), before and after 45 min of 1% cyclopentolate hydrochloride application, were performed. For a control group (cycloplegia-free, Group 2), 24 eyes of 24 age- and sex-matched healthy cases were evaluated twice at 45 min intervals. The results obtained from the groups were compared statistically. RESULTS: The mean ages of the groups were 23.04 ± 3.42 (range, 18-29) and 22.4 ± 2.05 (range, 18-27) years for Groups 1 and 2, respectively (p=0.259). In Group 1, measurements between the two analyses were significantly different for the values of anterior chamber depth (ACD), anterior chamber angle (ACA), and anterior chamber volume (ACV) (p<0.05), whereas no statistical difference was found for the central corneal thickness (CCT) and keratometry (K1, K2) measurements. In Group 2, none of these parameters were statistically different between the two analyses. CONCLUSIONS: Topically applied 1% cyclopentolate hydrochloride caused an increase in the ACD and ACV values, and a decrease in the ACA value. However, it had no significant effect on the CCT and keratometry measurements. It is important to consider these effects when using the Pentacam device on young adults with cycloplegia and when applying it for various reasons.