Acute drug reaction to phenylephrine and tropicamide collyrium in a late-preterm newborn: a case report.

BACKGROUND: Collyrium administration is a common procedure in the neonatal ward, both in preterm and at term babies. Various molecules are used to induce mydriasis and cycloplegia: among them, phenylephrine and tropicamide are the most popular, and their administration is generally considered safe. CASE PRESENTATION: A 35 + 2 weeks-old, 2510 g, well-appearing male newborn required an ophthalmologic evaluation after a doubtful red reflex test. A collyrium with 1% phenylephrine and 0.95% tropicamide was administered prior to the consult, one drop per eye. Two minutes after the administration, the baby developed a severe apnea that required tactile stimulation. Moreover, the area around his eyes became visibly pale. Three minutes later, the baby became severely bradycardic (59 bpm), but remained in good general condition, so that resuscitation maneuvers were not required. Bradycardia lasted for almost three hours and then gradually resolved. CONCLUSIONS: Cardiopulmonary manifestations, such as bradycardia and even cardiopulmonary arrest, are severe complications that can happen after phenylephrine collyrium administration in preterm newborns. However, they have been described in babies below 1500 g or with concurrent respiratory manifestations. Our patient, on the other hand, was late preterm, and never required a ventilatory support prior to the collyrium administration. Practitioners who deal with premature babies, even if late preterm, must be aware of these possible complications and administer phenylephrine collyrium carefully, where cardiopulmonary resuscitation equipment and personnel are available.

Efficiency and safety of phenylephrine and tropicamide used in premature retinopathy: a prospective observational study.

BACKGROUND: To determine effects and side effects of topical application of phenylephrine 2.5% and tropicamide 0.5% combination in preterm infants. METHODS: In this prospective observational study, 60 infants undergoing retinopathy of prematurity (ROP) screening were prospectively observed. Pupillary diameter, blood pressure, heart rate, and oxygen saturation were monitored before and after up to 24 h during ROP screening examinations. RESULTS: The mean pupillary diameter 1 h after the instillation of drops was 5.58 ± 0.75 mm for both eyes. The mean systolic and diastolic pressure and oxygen saturation of infants did not change statistically until the end of the study. The average heart rate decreased by a mean of 4.96 beats/minute from the baseline following eye drops instillation. General condition deterioration, fall in oxygen saturation and bradycardia were observed in 4 infants that already had respiratory distress syndrome. CONCLUSION: The phenylephrine 2.5% plus tropicamide 0.5% drop is effective and safe as mydriatic combination for retinopathy of prematurity screening. In infants with an additional systemic disease such as respiratory distress syndrome, the side effects of mydriatic drops may be more common. Such babies should be kept under close observation. TRIAL REGISTRATION: The trial was retrospectively registered on 28 February 2018. The ClinicalTrials.gov Identifier is NCT03448640.

Allergic contact dermatitis to phenylephrine eye drops in an infant.

Ophthalmic medications used for diagnostic or therapeutic purposes are common causes of allergic contact dermatitis around the eyes. We report a case of periocular allergic contact dermatitis due to tropicamide and phenylephrine eye drops in a 1-year-old infant.

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.

Acute angle-closure glaucoma in retinopathy of prematurity following pupil dilation.

BACKGROUND: Pupil dilation is a known risk factor for acute angle-closure glaucoma. Regular retinal evaluation is necessary for retinopathy of prematurity (ROP) cases. An acute attack of angle-closure glaucoma following pupil dilation in regressed ROP has never been reported. CASE PRESENTATION: A five-year-old girl presented to the hospital for a routine retina check-up. The patient was born prematurely with a gestation age of 27 weeks and a body weight of 980 grams. She had a history of stage 4A ROP in the right eye and received scleral buckling. After pupil dilation with 1 % tropicamide and 10 % phenylephrine for retinal examination, acute elevation of intraocular pressure (IOP) was observed in the right eye. Her IOP remained over 50 mmHg in the right eye even under treatment with oral acetazolamide and maximal tolerated doses of topical anti-glaucoma medications. Ultrasound biomicroscopy (UBM) showed that the angle in the right eye was closed 360 degrees circumferentially. In order to lower IOP, trabeculectomy with mitomycin C (0.2 mg/cc) was performed under general anesthesia. Postoperatively, the cornea became clear, the filtering bleb functioned well, and IOP returned to normal values. In the two-year follow-up, IOP was kept around 15 mmHg without anti-glaucoma medications. Although mild lens opacity was noted, her postoperative VA remained 20/200 in the right eye. CONCLUSION: Regular retinal evaluation will be necessary for the increasing number of ROP cases to be seen in the future. Ophthalmologists should bear in mind that pupil dilation for a retina check-up could result in acute angle-closure glaucoma in ROP patients.

Intravenous Abuse of Tropicamide in Opioid Use Disorder: Presentation of 2 Cases.

BACKGROUND: Tropicamide is an antimuscarinic ophthalmic solution used to produce short-acting mydriasis and cycloplegia. Topical abuse of ophthalmic solutions has been reported, but intravenous (IV) abuse of tropicamide seems to be a new phenomenon. CASES: The authors present 2 patients with concomitant IV tropicamide abuse and opioid use disorder. Patients were hospitalized and started on buprenorphine/naloxone treatment for opioid withdrawal. Patients' reports about tropicamide effects are remarkable, as they claimed that tropicamide increased the efficacy of heroin while decreasing and delaying the withdrawal symptoms. DISCUSSION: Although anticholinergics have been known to be abused for their euphoric effects, these cases' motivation to use tropicamide seemed to extend beyond its euphoric effect and was also based on its interaction with heroin. It is feared that tropicamide abuse may become more frequent. Health professionals should be aware of this trend so that symptoms of misuse and intoxication can be recognized, and ophthalmologists should consider the abuse potential of anticholinergic eye drops when prescribing them.

Abuse of tropicamide eye drops: review of clinical data.

Over the past 15 years, the increasing nonmedical use of tropicamide ophthalmic drops has been reported in Europe, coinciding with an increase in opioid addiction and drug-related mortality. Although tropicamide is generally known as a cheap alternative to heroin in Eastern Europe, it still appears to be a relatively new phenomenon that has arisen over the last decade. A narrative review was conducted of all the relevant sources published in more than five countries between January 1, 1975 and January 10, 2021. For bibliographic accuracy, the materials published in Russian and Italian were professionally translated to English. During the preparation of this report, we were able to interview five Russian-speaking patients who injected tropicamide in the past and we discuss another case of intravenous tropicamide use. This review was acknowledged by the institutional review board of the University of Missouri-Kansas City. All patients interviewed at the Unica Medical Center consented for their clinical information to be reported in a medical publication. We analyzed data from 50+ various sources and covered a variety of drug-related issues, including information on the extent, patterns, and trends in tropicamide use, its health consequences, and other clinical findings. The information provided in this article may help providers better detect tropicamide abuse and incorporate new rehabilitation strategies into the management of these patients.

Evaluation of efficacy of intracameral lidocaine and tropicamide injection in manual small-incision cataract surgery: A prospective clinical study.

Purpose: The study was conducted to evaluate efficacy of intracameral lidocaine hydrochloride 1% and tropicamide injection 0.02% for anaesthesia and mydriasis in manual small-incision cataract surgery (MSICS) and to report any adverse drug reaction. Methods: This was a randomized, prospective, observational study on 32 participants that took place from October 2021 to March 2022 (6 months). Patients between age group 40-75 year with nuclear sclerosis cataract and pupil diameter >6 mm in preoperative evaluation were included in the study. Patients with pseudoexfoliation, rigid pupil, senile miosis, history of uveitis, ocular trauma, recent ocular infections, with known allergy to tropicamide, all types of glaucoma were excluded from the study. Results: Thirty-two eyes with nuclear sclerosis cataract who underwent MSICS were studied. Fixed dose combination of 2 ml phenyl epinephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) intracamerally was used for mydriasis and analgesia. More than 7 mm pupillary dilatation was achieved within 20 seconds of injection in 29 cases (90.6%). Mild pain and discomfort was noted in 12 cases (37.5%). Postoperative day 1 unaided visual acuity was in the range of 6/18-6/12 for all patients and grade 1 iritis was seen in 7 cases (21.8%) which was self-limiting. No adverse event like corneal decompensation or TASS were noted. Conclusion: Thus, Intracameral injection of mydriatic provides rapid and sustainable mydriasis and analgesia for manual SICS.

Efficacy and safety of mydriatic microdrops for retinopathy of prematurity screening: an external pilot crossover randomized controlled trial.

OBJECTIVE: To study the efficacy and safety of mydriatic microdrops compared with standard drops for retinopathy of prematurity (ROP) screening. STUDY DESIGN: Preterm infants undergoing ROP screening received microdrops and standard drops of phenylephrine 1.67% and tropicamide 0.33% in a random allocation sequence at two consecutive weekly examinations. Primary outcome was pupil diameter measured by two masked observers at 45 (T45) and 90 (T90) minutes after instillation. RESULTS: Twenty-five infants were randomized. No differences observed in mean pupil diameter after either administration technique at all time points (T45 Mean Difference: -0.14; 95% Confidence Interval: -0.38, 0.09; p = 0.23). Heart rate values at T120 were lower after microdrop instillation (p = 0.046). Otherwise, adverse events did not differ after either administration technique. CONCLUSION: This pilot study provides evidence of microdrops mydriasis efficacy, while justifying a full-scale trial to confirm their non-inferiority compared with standard drops and provide more data about safety. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04623684.

Intraoperative mydriasis by intracameral injection of mydriatic eye drops: in vivo efficacy and in vitro safety studies.

BACKGROUND: This study investigated the efficacy and safety of intracameral injection of commercially available eye drops containing 0.5% tropicamide and 0.5% phenylephrine hydrochloride (Mydrin-P, Santen Pharmaceutical, Osaka, Japan). DESIGN: In vitro experiment and prospective clinical study at a private hospital. PARTICIPANTS AND SAMPLES: Mydrin-P was applied to confluent cultured human corneal endothelial cells, and the cellular morphology was examined. Clinical study subjects were 65 eyes of 65 patients that underwent phaco-emulsification and aspiration with intraocular lens implantation and received intracameral injection of Mydrin-P for poor mydriasis after preoperative topical instillation of mydriatics (intraocular mydriasis group; with five subgroups based on cause: diabetes, pseudo-exfoliation, post-surgery, uveitis, unknown). Controls, comprising 39 eyes of 39 patients, were not injected with Mydrin-P. METHODS: The ratio of pupillary diameter to corneal diameter was determined before and after injection of Mydrin-P. Corneal endothelial density was measured preoperatively and 3 months and 1 year postoperatively. MAIN OUTCOME MEASURES: Pupillary diameter and corneal endothelial density. RESULTS: Human corneal endothelial cell morphology was unaltered after Mydrin-P injection. The mean ratio of the pupillary diameter to corneal diameter increased in the intraocular mydriasis group (before: 54.2 ± 4.8%, after: 58.4 ± 6.6%; P < 0.001) and in the diabetes and unknown subgroups. The corneal endothelial cell density reduction rate 3 months and 1 year after surgery was not significantly different between the intraocular mydriasis group and controls. CONCLUSION: Intracameral injection of Mydrin-P appears to be effective and safe for dilating the pupil in cases with poor mydriasis after preoperative instillation of mydriatics.

Systemic adverse events after screening of retinopathy of prematurity with mydriatic.

PURPOSE: To evaluate systemic adverse events after screening for retinopathy of prematurity (ROP) performed with mydriatic. METHODS: This was a retrospective case series study. Medical records of consecutive patients who underwent screening for ROP with 0.5% phenylephrine and 0.5% tropicamide eyedrops were retrospectively reviewed. The score of abdominal distention (0-5), volume of milk sucked and volume of stool, along with systemic details (pulse and respiration rates, blood pressure and number of periods of apnea) were collected at 1 week and 1 day before ROP examination, and at 1 day after examination. Results were compared between the days before and after examination. Correlation between body weight at the time of examination and the score of abdominal distention was examined. The numbers of infants with abdominal and/or systemic adverse events were compared between pre- and post-examination periods. RESULTS: Eighty-six infants met the inclusion criteria. The score of abdominal distention increased from 2.0 at 1 day before examination to 2.3 at 1 day after examination (p = 0.005), and the number of infants who had worsened abdominal distension increased after examination (p = 0.01). Infants with lower body weight had a higher score of abdominal distention (p < 0.0001, r = -0.57). The number of infants with reduced milk consumption increased after examination (p = 0.0001), as did the number of infants with decreased pulse rate (p = 0.0008). CONCLUSIONS: Screening for ROP with mydriatic may have adverse effects on systemic conditions. Infants should be carefully monitored after ROP screening with mydriatic.

The local vasoconstriction of infant's skin following instillation of mydriatic eye drops.

BACKGROUND: Systemic absorption of eye drops is known to occur via the nasal mucosa, cornea, and conjunctiva. Diffusion of eye drops through the skin is previously unrecognized. Here, two cases are presented in which we observed skin pallor around the eyes after instillation of phenylephrine 2.5% drops. CASE 1: A 32-week gestational age premature infant had mydriatic eye drops instilled as part of retinopathy of prematurity screening. CASE 2: A term newborn dysmorphic infant underwent fundus examination to rule out ocular pathology. In both cases, discoloration of periorbital skin was observed 45 min following administration of drops. CONCLUSION: The risks of percutaneous toxicity must always be considered in children, especially in premature neonates, in whom the epidermal permeability barrier is frequently incompetent. Application of smaller drop size or wiping of overflowed drop from the skin may be useful to decrease the risk of systemic side effects.

Mydrane intracameral injection site can be an alternative to mydriatic drops instillation in cataract surgery.

The aim of this study is to compare Mydrane (combination of tropicamide 0.02%, phenylephrine 0.31% and lidocaine 1%) and mydriatic drops (tropicamide 1% and phenylephrine 10%) used for cataract surgery in terms of efficacy in pupil dilation and impact on corneal endothelial cell density (CD) and central corneal thickness (CCT). Prospective study including 64 eyes of 64 patients that underwent phacoemulsification with intraocular lens implantation. Patients were randomized into two groups: Mydrane group received: tropicamide and phenylephrine one day preoperatively and Mydrane during the surgery. Reference group received: tropicamide and phenylephrine preoperatively. Pupil size was measured only in Mydrane group, in the same eye of the same patient one day preoperatively after mydriatic drops were given and during the surgery, after intracameral Mydrane injection. CD and CCT were evaluated one day preoperatively and one month postoperatively in all patients and compared between Mydrane and reference groups. The results show CCT and CD significantly decreased after surgery in both groups. There is no difference in this decrease between groups. In Mydrane group there was no difference in dilated pupil diameter between Mydrane and mydriatic drops. Gender, diabetes mellitus, POAG, alpha-1 blocker treatment failed to affect pupil dilation obtained with Mydrane. Cataract surgery affects CCT and CD regardless of which mydriatic protocol had been used. Pupil diameter was similar after drops instillation and after Mydrane injection in all patients from the Mydrane group.

OCT-Angiography: Mydriatic phenylephrine and tropicamide do not influence retinal microvasculature in macula and peripapillary region.

PURPOSE: Optical coherence tomography angiography (OCT-A) enables visualization of retinal microcirculation. As a potential influence of mydriatic eye drops on retinal vessel density (VD) was proposed, the purpose of the present study was to investigate an influence of 5% phenylephrine and 0.5% tropicamide on macula and peripapillary VD. METHODS: 30 eyes of 30 healthy persons were measured by en face OCT-A (Spectralis OCT II, Heidelberg Engineering, Heidelberg). Scans of the macula (12 sectors, region of interest, ROI: 6.10 mm2) and peripapillary region (4 sectors, ROI: 2.67 mm2) were performed before (-) and 30 minutes after application of phenylephrine 5% and tropicamide 0.5% (+) eye drops (scan size was 8.41 mm2). Macula microcirculation was quantified in 3 retinal layers (superficial vascular plexus (SVP), deep capillary plexus (DCP), intermediate capillary plexus (ICP)). Data analysis was performed with the Erlangen-Angio-Tool. RESULTS: (I) Mean VD was 33.03±2.3 (SVP), 23.53±2.9 (ICP) and 25.48±4.2 (DCP) before and 33.12±2.4 (SVP), 23.74±2.9 (ICP) and 25.82±4.0 (DCP) with mydriasis respectively. (II) Sectorial analysis: 30.63±2.9-34.45±2.9 (-) and 31.04±2.9-34.34±2.7 (+) in SVP; 22.61±2.9-24.93±3.2 (-) and 22.75±2.5-25.20±3.0 (+) in ICP; 24.56±4.7-26.45±3.4 (-) and 25.00±4.1-27.07±3.5 (+) in DCP. (III) Peripapillary region showed a mean VD of 31.82±3.8 before and 31.59±4.3 after mydriasis. Sectorial analysis of VD yielded a range of 31.04±4.1-32.65±3.8 (-) and 30.98±4.4-31.89±4.1 (+). (IV) Macula and peripapillary VD were not different before and after mydriasis (p>0.05). CONCLUSION: Pharmacologic mydriasis did not influence retinal microcirculation in macula and peripapillary region enabling OCT-A scans with enhanced imaging process and scan quality.

[Same-eye comparison of pupillary dilation with an intraoperative standardized intracameral combination of mydriatics (Mydrane®) versus a preoperative ophthalmic (Mydriasert®) in standard cataract surgery in non-diabetic patients (French translation of the article)]. / Comparaison intra-individuelle de la dilatation pupillaire par une solution intracamérulaire standardisée combinée de mydriatiques (Mydrane®) en peropératoire versus un insert ophtalmique (Mydriasert®) en préopératoire dans la chirurgie de la cataracte standard de patients non diabétiques.

INTRODUCTION: Cataract surgery is the most commonly performed surgery in the world, and its success depends in part on the quality of mydriasis. PURPOSE: To compare, for the same eye, the pupillary dilation obtained with Mydrane® (standardized intracameral solution of 0.02% tropicamide, combined with 0.31% phenylephrine and 1% lidocaine) intraoperatively versus Mydriasert® (0.28mg tropicamide insert and 5.4mg phenylephrine) with a contact time between 45 and 60 minutes in the preoperative period. METHODS: Single center prospective study from November 2016 to January 2018 at the Laveran Army Instructional Hospital in Marseille. Patients referred for surgery were dilated at the preoperative consultation with Mydriasert®. The pupillary diameter after 45-60 minutes of contact with the insert was manually measured, by two different examiners, through the "iris image" tab of the Pentacam® elevation topography. Patients were dilated on the day of their cataract surgery with 0.2cc of Mydrane® injected in the anterior chamber through a paracentesis. Thirty seconds later, prior to injection of viscoelastic, an eye photograph was taken by screen capture. The pupillary diameter was evaluated by two different examiners with to the Piximeter 5.9 metrology software. The difference in pupil dilation between Mydriasert® and Mydrane® was tested with the paired series Student t-test. RESULTS: In total, 111 eyes of 82 patients were included. Mydriasert® achieved a mean pupillary dilation of 7.21±0.79mm. The mydriasis obtained with Mydrane® averaged 6.35±0.8mm. This difference of 0.86mm was statistically significant (P<0.001) with a confidence interval of 95% [-0.97; -0.74]. CONCLUSION: On average, Mydrane® dilates the pupil less than Mydriasert®. However, the mydriasis obtained with Mydrane® remains comfortable for the performance of the capsulorhexis. It helps save preoperative time and affords additional anesthetic to the cataract surgery. Nevertheless, the use of Mydriasert® is beneficial when extra mydriasis is required.

[The influence of phenylephrine and tropicamide on higher order monochromatic aberrations]. / Einfluss von Phenylephrin und Tropicamid auf Aberrationen höherer Ordnung.

BACKGROUND: For wave-front guided corneal surgery, measuring higher order monochromatic aberrations in mydriasis is needed. However, a potential influence of mydriatic drugs on such aberrations could distort the ablation profile. METHOD: Wave-front analysis was carried out on 20 (tropicamide) and 19 (phenylephrine) eyes after dark adaptation, followed by measurement after the instillation of the mydriatics one after another. RESULTS: Phenylephrine had no significant influence on the wave-front; neither sphere nor RMS data differed from those taken after dark adaptation. After instilling tropicamide, significant changes in Z(2) (0) and, in parallel, also of the sphere were found. The RMS showed no significant difference, only the spherical aberration Z(4) (0) was reduced by an average of 0.035 microm. CONCLUSION: The wave-front changes individually through the mydriasis due to phenylephrine and tropicamide. In the case of tropicamide, the deviation is statistically significant. Therefore, abandonment of these mydriatics before refractive surgery can be recommended, as can the use physiological pupil dilatation. Because of its lower influence, phenylephrine should be the first choice if dimout effects no adequate mydriasis.

Pharmacodynamics of a new ophthalmic mydriatic insert in healthy volunteers: potential alternative as drug delivery system prior to cataract surgery.

Cataract surgery requires a satisfactory degree of mydriasis throughout the entire operation. A phase I, open-labelled, randomised, cross-over trial was conducted in 18 healthy volunteers to compare mydriasis obtained with subsequent administration of phenylephrine 10% and tropicamide 0.5% eyedrops or a new insoluble-matrix retropalpebral ophthalmic insert containing 5.38 mg phenylephrine and 0.28 mg tropicamide. Phenylephrine serum concentrations were measured over 6 hr following each treatment administration. Secondary end-points included cardiovascular, general and local tolerance and quantification of bacterial colonisation of the conjunctiva and the cultured insert, respectively. When normalized to the pupil diameter after conventional treatment, the diameter achieved with the insert was 1.13 (95% confidence interval, 0.94-1.48, P=0.38). Moreover, standard eye drops provided faster effective mydriasis than the insert, starting 30 min. as compared to 90 min. upon treatment administration (P<0.01, repeated-measures ANOVA). Phenylephrine concentrations remained almost undetectable for both treatments and no change in heart rate or blood pressure were observed throughout the study. Only three superficial punctuate keratitis were diagnosed with the insert and two with the eye drops. No significant bacterial contamination of conjunctiva swab and cultured insert was observed. The new insoluble-matrix retropalpebral ophthalmic mydriatic insert produced similar but delayed effective and prolonged mydriasis as compared to the standard delivery system. In addition to its potential usefulness in patients undergoing cataract surgery, such new ophthalmic delivery system may be an advantage in children who need to undergo fundus photography due to the single administration and excellent tolerance as well.

Retinopathy of prematurity screening leading to cardiopulmonary arrest: fatal complication of a benign procedure.

A 6-week-old female infant born at 31 weeks of gestation was brought to the ophthalmology office for retinopathy of prematurity (ROP) screening. One drop of phenylephrine (2.5%) and tropicamide (1%) ophthalmic solution was instilled in each eye for ROP evaluation. She was breast fed about 5 min after receiving the medication. She was covered in a blanket and soon her mother could not feel her suckling. Cardiopulmonary resuscitation was initiated with return of spontaneous circulation in 1-2 min. She was admitted to the paediatric intensive care unit and monitored overnight. After an uncomplicated hospital course, she was discharged the following day. It was determined that the eye drops had induced cardiopulmonary arrest (CPA) as apnoea and bradycardia of prematurity resolve by 36 weeks and CPA occurred within minutes of the medication administration. Identification of CPA, prompt intervention and awareness of the offending agent is of prime importance in management of such complications.

Time-Course of Changes in Choroidal Thickness after Complete Mydriasis Induced by Compound Tropicamide in Children.

PURPOSE: The aim of this study was to investigate the time-course of changes in choroidal thickness (ChT) following complete mydriasis induced by compound tropicamide. METHODS: ChT was measured by OCT with the enhanced-depth imaging technique (Spectralis HRA+OCT, Heidelberg Engineering, Germany) at nine locations of the fundus: subfoveal ChT (SFChT) and ChT at 1 mm and 3 mm from the fovea in four quadrants. Mydriasis was induced with compound tropicamide (0.5% tropicamide plus 0.5% phenylephrine hydrochloride, three doses at 5-minute intervals). Measurements were conducted prior to the instillation and at 0, 30, and 60 min following complete mydriasis. Results at different time-points were compared using repeated-measures ANOVA to investigate the time-course of the changes. RESULTS: Thirty-nine subjects (mean age 11.9±2 years; 16 males and 23 females) were enrolled in the study. Compound tropicamide resulted in a statistically significant decrease in SFChT at 0, 30, and 60 min after complete mydriasis, as compared to baseline (-5±4 µm, -12±4 µm, and -13±4 µm, respectively; all P<0.0001). No significant changes were detected in the parafoveal choroid except at 1 mm temporal (T1mm) and nasal (N1mm) to the fovea at 30 and 60 min (T1mm: -6±4 µm and -7±5 µm at 30 and 60 min; N1mm: -6±4 µm and -7±5 µm at 30 and 60 min, respectively; all P<0.0001). Repeated-measures ANOVA showed a significant interaction between the time after complete mydriasis and the effect of the mydriasis agent. CONCLUSIONS: Complete mydriasis induced by compound tropicamide led to choroidal thinning, and the magnitude varied over time.