Case report: Topical pilocarpine ameliorated the accommodation loss and pupillary dilation after micropulse transscleral laser treatment.

BACKGROUND: The present study elucidates a common significant postoperative complication of micropulse transscleral laser treatment (mTLT) and explores its potential management strategies for younger patients with good central vision. CASE PRESENTATION: Three younger Chinese glaucoma patients with good central vision maintained high intraocular pressures (IOPs) (36, 25, and 30 mmHg) on maximally tolerated topical anti-glaucoma medications. All patients were treated with mTLT because of a higher risk of complications with filtering surgery. After the procedure, their best-corrected visual acuities were not significantly changed, IOPs were significantly decreased, and the number of topical anti-glaucoma medicines was gradually decreased. However, all patients complained about reduced near visual acuity (NVA) for 1-5 months. Slit-lamp examination revealed pupillary dilation, and binocular accommodative function examination indicated accommodation loss. After treatment with 2% topical pilocarpine, all patients reported an improvement in NVA. Among them, we could observe pupillary constriction, recovery of accommodation function, and improved NVA, even discontinuation of pilocarpine in Patient 2. CONCLUSION: In younger patients with good central vision, topical pilocarpine might ameliorate accommodation loss and pupillary dilation after mTLT.

Effect of nose twitching on the pupillary dilation in awake and anesthetized horses.

Pupillometry is used in humans to monitor pain, nociception and analgesia. This single-center, non-randomized, non-blinded intervention trial, evaluated the effect of nose twitching on the pupil size in awake, sedated, and anesthetized horses. Pupil height (H) and length (L) were measured before (Be) and after (Af) nose twitching in fourteen non-painful adult awake horses (T0). The percentage of variation (PSV) was calculated (PSVTn = [(TnAf-TnBe)/TnBe]*100). Measurements were repeated (Tn) after acepromazine (0.04 mg kg-1 IV) (T1), romifidine (0.04 mg kg-1 IV) (T2), morphine (0.1 mg kg-1 IV) (T3), after anesthesia induction with diazepam (0.05 mg kg-1 IV) and ketamine (2.2 mg kg-1 IV), at the time the horse was placed on the operating table (T4) and when the expiratory fraction of sevoflurane was 2% (T5). HAf vs. HBe, LAf vs. LBe as well as PSVH vs. PSVL at each time were compared with a Mann-Whitney Wilcoxon test. The PSVL and PSVH, as well as HBe and LBe over time were compared with the Skillings-Mack test followed by a Wilcoxon test for paired data to make pairwise comparisons (Tn + 1 vs. Tn). In non-sedated horses (T0), the application of the nose twitch induced a significant increase in pupil length (LT0Be: 17.09 [16.05; 19.67] mm versus LT0Af: 19.52 [18.74; 21.40]) mm (p = 0.004). Thirty minutes after acepromazine administration (T1), nose twitching induced a significant increase in pupil length (LT1Be: 16.45 [14.80; 18.66] mm versus LT1Af 18.31 [17.20; 20.52] mm) (p = 0.016) and height (HT1Be: 8.44 [5.68; 12.04] mm versus HT1Af: 11.09 [7.97; 14.3] mm) (p < 0.001). PSVHT1 was significantly greater than PSVLT1 (p = 0.025). PSVH was higher at T1 than at T0 (p = 0.04). It was also significantly higher at T1 than at T2 (p < 0.001). Romifidine induced mydriasis (HT2Be 16.95 [14.73; 18.77] mm versus HT1Be 8.44 [5.68; 12.04] mm) (p < 0,001) (LT2Be 19.66 [18.45; 20.41] mm versus LT1Be 16.45 [14.80; 18.66] mm) (p < 0.001). The results suggest that nose twitching induced a pupillary dilation in the awake horse. This effect was potentiated after the administration of acepromazine but disappeared after the administration of romifidine.

Risk Factors for Nondiagnostic Imaging in a Real-World Deployment of Artificial Intelligence Diabetic Retinal Examinations in an Integrated Healthcare System: Maximizing Workflow Efficiency Through Predictive Dilation.

OBJECTIVE: In the pivotal clinical trial that led to Food and Drug Administration De Novo "approval" of the first fully autonomous artificial intelligence (AI) diabetic retinal disease diagnostic system, a reflexive dilation protocol was used. Using real-world deployment data before implementation of reflexive dilation, we identified factors associated with nondiagnostic results. These factors allow a novel predictive dilation workflow, where patients most likely to benefit from pharmacologic dilation are dilated a priori to maximize efficiency and patient satisfaction. METHODS: Retrospective review of patients who were assessed with autonomous AI at Johns Hopkins Medicine (8/2020 to 5/2021). We constructed a multivariable logistic regression model for nondiagnostic results to compare characteristics of patients with and without diagnostic results, using adjusted odds ratio (aOR). P < .05 was considered statistically significant. RESULTS: Of 241 patients (59% female; median age = 59), 123 (51%) had nondiagnostic results. In multivariable analysis, type 1 diabetes (T1D, aOR = 5.82, 95% confidence interval [CI]: 1.45-23.40, P = .01), smoking (aOR = 2.86, 95% CI: 1.36-5.99, P = .005), and age (every 10-year increase, aOR = 2.12, 95% CI: 1.62-2.77, P < .001) were associated with nondiagnostic results. Following feature elimination, a predictive model was created using T1D, smoking, age, race, sex, and hypertension as inputs. The model showed an area under the receiver-operator characteristics curve of 0.76 in five-fold cross-validation. CONCLUSIONS: We used factors associated with nondiagnostic results to design a novel, predictive dilation workflow, where patients most likely to benefit from pharmacologic dilation are dilated a priori. This new workflow has the potential to be more efficient than reflexive dilation, thus maximizing the number of at-risk patients receiving their diabetic retinal examinations.

Recurrent unilateral pupillary dilation and transient visual blurring: A clinical challenge during hypoxia exposure in a male fighter pilot.

Hypoxia is an operational concern in military aviation, and fighter pilots should undertake altitude hypoxia training. Anisocoria is a significant clinical dilemma and may remain a diagnostic challenge for specialists. We present a case of atraumatic unilateral mydriasis during hypobaric chamber training. Our diagnostic dilemma is novel and unique because the authors reported no similar presentation yet, it occurred in a fighter pilot whose occupational future depends on having normal vision, and second, the presence of hypoxia seems to trigger symptoms.

Influence of mydriasis on foveal duplication artifact.

In this case report, we describe a rare imaging finding of foveal duplication identified on spectral domain optical coherence tomography (OCT) through undilated pupils in a 49-year-old asymptomatic anxious lady with type 2 diabetes mellitus who visited the retina clinic for diabetic retinopathy screening. A simple patient counseling for cooperation during a repeat OCT scan with dilated pupils revealed that the twin fovea-like duplication was an illusion. This case illustrates the necessity of pupillary dilation and reimaging in the presence of unusual artifacts, such as foveal duplication, to prevent clinicians from ordering unnecessary additional tests.

Pupillary Pain Index Predicts Postoperative Pain but Not the Effect of Peripheral Regional Anaesthesia in Patients Undergoing Total Hip or Total Knee Arthroplasty: An Observational Study.

Background and Objectives: The pupillary pain index (PPI) allows the evaluation of intraoperative nociception by measuring pupillary reaction after a localized electrical stimulus. It was the objective of this observational cohort study to investigate the pupillary pain index (PPI) as a method to evaluate the fascia iliaca block (FIB) or adductor canal block (ACB) sensory areas during general anaesthesia in orthopaedic patients with lower-extremity joint replacement surgery. Materials and Methods: Orthopaedic patients undergoing hip or knee arthroplasty were included. After anaesthesia induction, patients received an ultrasound-guided single-shot FIB or ACB with 30 mL and 20 mL of 0.375% ropivacaine, respectively. Anaesthesia was maintained with isoflurane or propofol/remifentanil. The first PPI measurements were performed after anaesthesia induction and before block insertion, the second at the end of surgery. Pupillometry scores were evaluated in the area of the femoral or saphenous nerve (target) and C3 dermatome (control). Primary outcomes were differences between PPIs before and after peripheral block insertion as well as the relationship between PPIs and postoperative pain scores; secondary outcomes were the relationship between PPIs and opioid requirements after surgery. Results: PPI decreased significantly from the first to the second measurement (4.17 ± 2.7 vs. 1.6 ± 1.2, p < 0.001 for target; 4.46 ± 2.7 vs. 2.17 ± 2.1, p < 0.001 for control). Control and target measurements did not show significant differences. A linear regression analysis showed that early postoperative pain scores could be predicted with intraoperative piritramide with improved prediction after adding PPI scores, PCA opioids and surgery type. Forty-eight-hour pain scores at rest and in movement were correlated with intraoperative piritramide and control PPI after the PNB in movement and with second-postoperative-day opioids and target PPI scores before block insertion, respectively. Conclusions: While the effect of an FIB and ACB could not be shown with PPI postoperative pain scores due to a large effect of opioids, perioperative PPI was shown to be associated with postoperative pain. These results suggest that preoperative PPI may be used to predict postoperative pain.

Pupil dilation evaluation of two mydriatic dosing profiles delivered by the Optejet®.

Aim: To compare pupil dilation achieved by a single microdose versus two microdoses of tropicamide-phenylephrine fixed combination (TR-PH FC) delivered by the Optejet®. Patients & methods: In this assessor-masked, crossover, noninferiority study, 60 volunteers underwent two treatment visits and received either one (∼8 µl) or two sprays (∼16 µl) of TR-PH FC to both eyes in randomly assigned order. Results: At 35 min postdose, mean change in pupil diameter was 4.6 mm and 4.9 mm following one or two sprays, respectively. The estimated treatment group difference was -0.249 mm (standard error: 0.036; 95% CI: -0.320, -0.177). No adverse events were reported. Conclusion: A single microdose was noninferior to two microdoses of TR-PH FC and achieved clinically significant mydriasis in a timely manner. Clinical Trial Registration: NCT04907474 (ClinicalTrials.gov).

Pupil dilation efficacy and efficiency were evaluated using microdosing via the Optejet^®. The Optejet^® is a new ophthalmologic drug device that utilizes piezoelectric technology to deliver a fine, controlled, horizontal microdroplet spray with precise volume (∼8 µl), spray pattern and velocity. A single spray versus two sprays of tropicamide-phenylephrine fixed combination (TR-PH FC) were administered to both eyes anesthetic free. Efficacy and safety were evaluated at specific time intervals. The primary end point was the mean change in pupil diameter at 35 min compared with baseline. At 35 min, clinically relevant dilation was observed, with a mean change of 4.55 mm ± 0.68 for one spray and 4.88 ± 0.60 for two sprays. The treatment group difference of one spray of TR-PH FC was noninferior to two sprays (p < 0.001). Rapid dilation was observed at 15 min, and the proportions of eyes that achieved a pupil diameter of ≥6.0 mm were 74% and 83% of patients at 15 min with one spray and two sprays, respectively. The mydriatic agent was well tolerated with the delivery system even in the absence of topical anesthetic, with no ocular or system adverse events reported. Mydriasis is a vital component of routine eye healthcare, and the current standard-of-care mydriatic eye drops potentially have limitations, including contamination, spillage and burning/stinging. Delivery of a mydriatic with the Optejet^® may improve patient care flow in the clinical office setting.

Medical Student Attitudes Toward the Use of Peer Physical Exam for Learning Fundoscopy.

Background Peer physical examination learning is commonly practiced in medical schools during preclinical curricula and has been shown to improve empathy for patients. While there is literature regarding medical student attitudes toward peer physical exam learning, no studies to date have specifically examined student attitudes toward fundoscopy and dilation of the eyes for the purposes of learning fundoscopy. This study evaluates medical student preferences with regards to learning fundoscopy on peers and explores attitudes toward alternate approaches. Methods First year medical students at the Icahn School of Medicine at Mount Sinai participated in a 2-hour fundoscopy skills workshop in March 2020. Following the session, the authors administered a voluntary survey querying students on attitudes toward peer physical exam learning and its use in learning peer fundoscopy. Primary study endpoints evaluated (1) student attitudes toward the use of peer physical exam learning, (2) learning benefit of the session, including student comfort with conducting the fundoscopy exam, and (3) empathy toward patients experiencing dilation. Secondary endpoints focused on alternative teaching methods and preferences for nonmydriatic fundoscopy. Analysis of survey data was performed using nonparametric Spearman's correlations, chi-square tests, t -tests, and Mann-Whitney U tests. Results A total of 51/138 (37%) students completed the survey, with 78% indicating they felt peer physical exam learning was a helpful instructional method, including for the fundoscopic exam. The session led to improved self-rated fundoscopy skills and empathy for patients. However, when considering learning with dilation versus alternative nonmydriatic techniques, 96% of students indicated a preference for using alternative nonmydriatic techniques. Conclusion This study found that students' attitudes toward fundoscopy generally aligned with their overall peer physical exam preferences. However, they preferred not using dilation and learning with nonmydriatic fundoscopic techniques. Assessing student learning preferences and incorporating novel instructional tools can help facilitate more successful fundoscopy skills acquisition. These considerations are particularly important in the context of COVID-19 and with advances in teleophthalmology.

Fixed dilated pupils in Covid-19 ARDS patients under rocuronium, reversed after discontinuation.

Neuromuscular Blockade Agents (NMBA) are used in the management of moderate and severe Acute Respiratory Distress Syndrome (ARDS) patients. They have never been reported to present Central Nervous System adverse reactions. Shortage of cis-atracurium during the pandemic, led to the use of rocuronium. We report three patients with Covid-19 ARDS, who presented bilateral dilated, non-reactive pupils, after continuous rocuronium infusion. Brain CT findings were unremarkable and transcranial doppler tracings did not suggest brain edema or hemorrhage. NMBA's discontinuation led to reversal of the pupillary dilation. We believe that impairment of Blood-Brain-Barrier, due to Covid-19, led rocuronium access into the Central Nervous System, leading to this adverse effect. Clinicians should be aware of this adverse reaction when managing patients with Covid-19 ARDS warranting NMBA use.

Mydriasis with micro-array print touch-free tropicamide-phenylephrine fixed combination MIST: pooled randomized Phase III trials.

Design: Prospective, double-masked, controlled, cross-over superiority studies. Materials & methods: Eligible volunteers in two pooled Phase III trials received microdosed mydriatics. MIST-1 study subjects received fixed-combination TR-PH, phenylephrine 2.5% (PH) or tropicamide 1% (TR). MIST-2 study subjects received TR-PH or placebo. Mean change from baseline in pupil diameter was measured by digital pupillometry at 35 min postadministration. Results: Pooled efficacy analysis included 131 subjects. Compared with TR-PH, treatment group difference in 35-min change in mean pupil dilation from baseline was 0.58 mm (p < 0.0001) with TR, 3.87 mm (p < 0.0001) with PH and 4.65 mm (p < 0.0001) with placebo. Adverse events reported were infrequent, transient and mostly mild. Conclusion: TR-PH demonstrated superior pupil dilation compared with each component and placebo. TR-PH was safe & well-tolerated.

Predicting zonular strength based on maximum pupillary mydriasis in patients with pseudoexfoliation syndrome.

Pseudoexfoliation Syndrome (PXFS) is considered a systemic disorder with significant ocular manifestations ranging from corneal decompensation, non-dilating pupil, zonular weakness, subluxated lens, and glaucoma. PXFS may lead to increased complications during routine cataract surgery. Zonular dialysis is a common complication during or after cataract surgery in such patients. However, not all patients with pseudoexfoliation are at a higher risk. We hypothesize that there is an inverse correlation between the maximum pupillary dilation and the degree of zonular disintegration. Available evidence supporting the hypothesis is discussed. We propose a new clinical classification for predicting the zonular strength based on the maximum pupillary dilation so that it can serve as a guide to identify PXFS patients who are at high risk of complications during or after cataract surgery.

Progressive hemifacial atrophy with characteristic ocular manifestations in a Chinese patient with a CRB1 mutation.

Progressive hemifacial atrophy (PHA) is mainly characterized by asymmetrical atrophy of craniofacial tissue; however, 10% to 30% of patients with PHA exhibit ocular manifestations. Here, we describe abnormal ocular findings in a Chinese patient with PHA. The patient was a 29-year-old Chinese man. Characteristic ocular findings in his affected eye included keratic precipitate, corneal endothelial degeneration, fundus tessellation, pupillary dilation, direct light reflex loss, and visual evoked potential alteration. Whole exosome sequencing revealed that the patient harbored a mutation in the CRB1 gene; this gene has been associated with various retinal dystrophies. During 10 years of follow-up, the patient's ocular status remained stable. To the best of our knowledge, this is the first report of ocular manifestations of PHA in a Chinese patient, and the first report of a CRB1 mutation in a patient with PHA; these findings may inform future research regarding PHA.

Effect of Tropicamide on Laser Flare Meter Measurements in Patients with Pseudoexfoliation.

PURPOSE: To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation. METHODS: Thirty-three eyes of 33 patients with pseudoexfoliation were enrolled. Patients with the history of other ocular diseases, intraocular surgeries, and the presence of severe posterior synechia were excluded. Besides routine ophthalmological examination, ACAF levels were measured by laser flare meter device (Kowa FM 600) before and after instillation of 1% tropicamide. RESULTS: The mean age of 33 patients was 67.3±7.1 (53-85) years. Patients had a mean best corrected visual acuity of 0.25±0.41 (1.80-0.00) logMAR, cup-to-disc ratio of 0.45±0.22 (0.2-1), and IOP of 15.33±2.82 (9-20) mmHg. Although the mean ACAF value increased from 14.68±8.40 (3.4-40.4) photon/ms predilation to 15.41±10.74 (3.8-46.8) photon/ms post-dilation, the difference was not statistically significant (p=0.835). CONCLUSIONS: ACAF values in patients with pseudoexfoliation did not significantly differ after instillation of 1% tropicamide.

[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.

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.

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: A hundred and eleven 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.

Itsy Bitsy Spider : Infants React with Increased Arousal to Spiders and Snakes.

Attention biases have been reported for ancestral threats like spiders and snakes in infants, children, and adults. However, it is currently unclear whether these stimuli induce increased physiological arousal in infants. Here, 6-month-old infants were presented with pictures of spiders and flowers (Study 1, within-subjects), or snakes and fish (Study 1, within-subjects; Study 2, between-subjects). Infants' pupillary responses linked to activation of the noradrenergic system were measured. Infants reacted with increased pupillary dilation indicating arousal to spiders and snakes compared with flowers and fish. Results support the notion of an evolved preparedness for developing fear of these ancestral threats.

Causes and management of small pupil in patients with cataract.

BACKGROUND: The purpose of the study was to present the causes and management of small pupil (<6 mm) in Greek patients with cataract. METHODS: About 1144 consecutive patients with cataract comprised the study group. The pupil size was measured after maximal dilation by means of Rosenbaum cards and Colvard pupillometer. Dilation regimen included phenylephrine 10%, tropicamide 1%, cyclopentolate 1%, and ketorolac trometamol 0.5% administered 3 times at 5 min intervals starting 1 h before surgery. The presence of possible risk factors for small pupil was recorded. The need of additional maneuvers and devices to dilate the pupil during cataract surgery was examined, and the complication rate in cases with small pupils was recorded. RESULTS: Small pupil was observed in 78 out of 1144 eyes (6.8%, 95% confidence interval = 5.2%-8.8%). Nine eyes had pupil size <4 mm (0.78%) preoperatively. Six cases (0.52%) developed intraoperative pupillary miosis. The major cause of small pupil was pseudoexfoliation (PEX) in 47.4% (37/78) of patients. No significant associations were observed regarding age, gender, history of diabetes mellitus, the maturity of cataract, and phacodonesis. Techniques for small pupil management included pupil stretching in 14 cases (17.9%), use of iris hooks in 6 cases (7.7%), iris sphincter cuts in 2 cases (2.6%), and placement of a Malyugin Ring in 4 cases (5.1%). Seven eyes (9%) with small pupil had capsular rupture versus 16 eyes (1.5%) with normal dilation (P < 0.001). CONCLUSIONS: Small pupil is not very common in Greek population, is mostly caused by PEX, and it is associated with increased complication rate.

Effect of pupillary dilation on Haigis formula-calculated intraocular lens power measurement by using optical biometry.

PURPOSE: The purpose of this study was to evaluate the effect of pupillary dilation on the Haigis formula-calculated intraocular lens (IOL) power and ocular biometry measurements by using IOLMaster(®). METHODS: A prospective study was performed for biometry measurements of 373 eyes of 192 healthy subjects using the IOLMaster at the outpatient department of King Chulalongkorn Memorial Hospital from February 2013 to July 2013. The axial length (AL), anterior chamber depth (ACD), keratometry (K), and IOL power were measured before and after 1% tropicamide eye drop instillation. The Haigis formula was used in the IOL power calculation with the predicted target to emmetropia. Each parameter was compared by a paired t-test prior to and after pupillary dilation. Bland-Altman plots were also used to determine the agreement between each parameter. RESULTS: The mean age of the subjects was 53.74±14.41 years (range 18-93 years). No differences in AL (P=0.03), steepest K (P=0.42), and flattest K (P=0.41) were obtained from the IOLMaster after pupillary dilation. However, ACD and IOL power were significantly different postdilation (P<0.01 and P<0.01, respectively). In ACD and IOL power measurements, the concordance rates were 93.03% and 97.05% within 95% limits of agreement (-0.48 to 0.26 mm and -1.09 to 0.88 D, respectively) in the Bland-Altman plots. CONCLUSION: Biometry measurements in the cycloplegic stage should be considered in the IOL formulas that use parameters other than AL and K.