Pharmacological Pupil Dilation Research Articles

Affordable ultra-widefield smartphone PedCam for comprehensive pediatric retinal examination

Widefield fundus photography is critical for the detection, documentation, and management of pediatric eye diseases. Existing clinical pediatric fundus cameras offer a limited field of view (FOV) and suboptimal image contrast, hindering comprehensive peripheral retina examination. Additionally, the high cost and lack of portability of commercial devices restrict their use in resource-limited settings. We introduce a cost-effective smartphone-based pediatric camera (PedCam) that provides a 180° eye angle (126° visual angle) snapshot FOV. Utilizing trans-pars planar illumination, the device enables nonmydriatic imaging by allocating the pupil exclusively for imaging, eliminating the need for pharmacological pupillary dilation. By adjusting the optical axis of the PedCam relative to the ocular axis, the effective FOV can be expanded up to 240° eye angle (180° visual angle), enabling complete retinal evaluation. This innovative smartphone PedCam represents a significant advancement in affordable telemedicine for the screening, monitoring, and management of retinopathy of prematurity and other pediatric eye conditions.

Optimizing axial length measurement success in advanced cataract patients through pupil dilation.

To evaluate the impact of pharmacologic pupil dilation on axial length (AL) measurement in patients with dense cataracts and previous failed AL measurements carried out without pupil dilation. Retrospective case series. All participants underwent swept-source optical coherence tomography (SS-OCT) biometry. Patients with unsuccessful AL measurements due to dense cataract underwent an additional SS-OCT biometric evaluation after pupil dilation, and the SS-OCT AL measurement was compared to the immersion ultrasound. The study included 3668 eyes of 3668 patients who underwent SS-OCT between October 2021 and March 2023. Of them, 102 eyes (2.8%) had failed AL measurements because of dense cataract. Eighty-seven of those 102 eyes underwent a repeat SS-OCT biometric exam following pharmacologic pupil dilation, after which AL measurements were successfully achieved in 27 (31.0%) of the 87 eyes. These measurements were found to be consistent with immersion ultrasound, supporting the validity of SS-OCT biometer measurements post dilation. Pharmacologic pupil dilation improved the rate of successful SS-OCT biometrically measured AL in patients with failed AL measurement due to dense cataract.

Extended-period AOSLO imaging in the living human retina without pupil dilation: a feasibility study.

In vivo imaging using an adaptive optics scanning laser ophthalmoscope (AOSLO) is challenging, especially over extended periods. Pharmacological agents, administered as eye drops, are commonly used to dilate the pupil and paralyse accommodation, to improve image quality. However, they are contraindicated in some scenarios. Here, we evaluate the feasibility and reproducibility of performing AOSLO imaging without pharmacological pupil dilation over 1.5 hours with visual stimulation. Through statistical analysis and theoretical modelling using a dataset of retinal and pupil images collected from six healthy, young, near-emmetropic participants between the ages of 20-30 years, we validate that the retinal image quality does not change significantly with time in the experimental session (p = 0.33), and that pupil size has a strong effect on image quality but is not the only contributing factor.

Capsular Tension Ring and Iris Hook Use in The Management of Cataract with Phacoemulsification Method in Dogs

The purpose of this study is to evaluate the surgical outcome of capsular tension ring and iris hook use during phacoemulsification in dogs with zonular weakness and miotic pupils. This study includes nineteen dogs (29 eyes) that underwent phacoemulsification (15 dogs/25 eyes) and extracapsular cataract extraction surgery (4 dogs/4 eyes) between February 2014 and February 2015. Patients with any ophthalmic problem other than cataracts were not included in the study. Some dogs did not achieve pharmacologic pupil dilation. These dogs required the use of iris hooks or the insertion of capsular tension rings. The capsular tension ring insertion was used in dogs with zonular rupture in more than half of the zonules. Capsular tension rings were inserted in cases of zonular dialysis and iris hooks were placed to widen the pupil. Fifteen dogs (25 eyes) underwent phacoemulsification, while 4 (4 eyes) received extracapsular cataract extraction (ECCE) surgery due to the difficulty of phacoemulsification in hypermature cataracts. Iris hooks were used in four dogs (8 eyes) for drug-resistant miotic pupils. Capsular tension rings were inserted to stabilize the lens capsule during phacoemulsification and to centralize the intraocular lens (IOL) in the bag. Capsular tension rings in cases of zonular dialysis and iris hooks in drug-resistant miotic pupils improved the success of cataract operations with phacoemulsification. Both are safe and useful for zonular weakness and for maintaining mydriasis during surgery.

Axial length and pharmacologic pupillary dilation in highly myopic patients.

To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length. Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation. Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08mm, 95% CI: 6.97 to 7.19mm) than controls (6.23mm, 95% CI: 5.94 to 6.52mm) after 30min of dilation (P < .0005). Fully dilated pupil size at 30min was significantly correlated with both refractive error (r = - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter. Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

Portable widefield fundus camera with high dynamic range imaging capability.

Fundus photography is indispensable for the clinical detection and management of eye diseases. Low image contrast and small field of view (FOV) are common limitations of conventional fundus photography, making it difficult to detect subtle abnormalities at the early stages of eye diseases. Further improvements in image contrast and FOV coverage are important for early disease detection and reliable treatment assessment. We report here a portable, wide FOV fundus camera with high dynamic range (HDR) imaging capability. Miniaturized indirect ophthalmoscopy illumination was employed to achieve the portable design for nonmydriatic, widefield fundus photography. Orthogonal polarization control was used to eliminate illumination reflectance artifacts. With independent power controls, three fundus images were sequentially acquired and fused to achieve HDR function for local image contrast enhancement. A 101° eye-angle (67° visual-angle) snapshot FOV was achieved for nonmydriatic fundus photography. The effective FOV was readily expanded up to 190° eye-angle (134° visual-angle) with the aid of a fixation target without the need for pharmacologic pupillary dilation. The effectiveness of HDR imaging was validated with both normal healthy and pathologic eyes, compared to a conventional fundus camera.

Evaluating Changes in Apparent Chord Mu after Pharmacological Pupil Dilatation

Introduction: Preoperative measurements of apparent chord mu length above 0.6 mm have been associated with higher risks for photic phenomena after cataract surgery with multifocal intraocular lenses (MFIOLs). Methods: This retrospective study evaluated patients scheduled for elective cataract surgery at a single tertiary medical center between 2021 and 2022. Pupil diameter and apparent chord mu length were analyzed for eyes with biometry measurements from IOLMaster 700 (Carl Zeiss Meditec, AG) under photopic light conditions, before and after pharmacological pupil dilatation. Exclusion criteria were visual acuity worse than 20/100, prior intraocular surgery, refractive surgery, iris-related procedures, or pupil abnormalities affecting dilatation. Apparent chord mu lengths before and after pupil dilatation were compared. In addition, multivariate linear regression analysis, using a stepwise method, was conducted to assess possible predictors of apparent chord values. Results: Included were 87 eyes of 87 patients. Mean chord mu length increased after pupillary dilatation from 0.32 ± 0.17 mm to 0.41 ± 0.17 mm for right eyes (p < 0.001) and from 0.29 ± 0.16 mm to 0.40 ± 0.22 mm for left eyes (p < 0.001). Seven eyes (8.0%) had an apparent chord mu of 0.6 mm and above pre-dilatation. Fourteen eyes (16.1%) with an apparent chord mu under 0.6 mm pre-dilatation had apparent chord mu of 0.6 mm or above post-dilatation. Conclusion: Apparent chord mu length significantly increases after pharmacological pupillary dilatation. Pupil size and dilatation status should always be considered during patient selection for a planned MFIOL using apparent chord mu length as a reference marker.

Advantageous effect of pupil dilation on the quality of optical biometry axial length measurement in individuals with dense cataract.

To evaluate the effect of pharmacologic pupil dilation on the quality of axial length (AL) measurement in patients with dense cataracts and previous low-quality AL measurements performed without dilation. Shaare-Zedek Medical Center, Jerusalem, Israel. Retrospective case series. All participants underwent swept-source optical coherence tomographic (SS-OCT) biometry. Those with low-quality AL measurements due to dense cataract underwent an additional SS-OCT biometric evaluation after pupil dilation, and the AL measurement of the same eye was recorded. 2076 patients underwent SS-OCT during the study period, and 177 (8.52%) had low-quality AL measurements because of dense cataract. 79 (44.63%, mean age 72.53 ± 13.27 years, 43 females) of those 177 patients underwent repeat SS-OCT biometric imaging after pharmacologic pupil dilation, and formed the study group. After pupil dilation, high-quality AL measurements were successfully obtained in 60 (75.95%) of the 79 eyes. The mean SD of the AL measurements decreased significantly ( P &amp;lt; .001), and the number of successful OCT scans per measurement increased significantly ( P &amp;lt; .001) after pupil dilation. The mean difference of the AL before and after pupil dilation was 0.03 ± 0.07 mm ( P &amp;lt; .001). Pharmacologic pupil dilation improved the quality of SS-OCT biometrically measured AL in patients with low-quality AL measurement due to dense cataract. These results could potentially improve postoperative refractive outcomes after cataract surgery and reduce the need of additional AL measurements by more complicated alternative means in this group.

Light color efficiency-balanced trans-palpebral illumination for widefield fundus photography of the retina and choroid

A wide-field fundus camera, which can selectively evaluate the retina and choroid, is desirable for better detection and treatment evaluation of eye diseases. Trans-palpebral illumination has been demonstrated for wide-field fundus photography, but its application for true-color retinal imaging is challenging due to the light efficiency delivered through the eyelid and sclera is highly wavelength dependent. This study is to test the feasibility of true-color retinal imaging using efficiency-balanced visible light illumination, and to validate multiple spectral imaging (MSI) of the retina and choroid. 530 nm, 625 nm, 780 nm and 970 nm light emission diodes (LED)s are used to quantitatively evaluate the spectral efficiency of the trans-palpebral illumination. In comparison with 530 nm illumination, the 625 nm, 780 nm and 970 nm light efficiencies are 30.25, 523.05, and 1238.35 times higher. The light efficiency-balanced 530 nm and 625 nm illumination control can be used to produce true-color retinal image with contrast enhancement. The 780 nm light image enhances the visibility of choroidal vasculature, and the 970 nm image is predominated by large veins in the choroid. Without the need of pharmacological pupillary dilation, a 140° eye-angle field of view (FOV) is demonstrated in a snapshot fundus image. In coordination with a fixation target, the FOV can be readily expanded over the equator of the eye to visualize vortex ampullas.

Changes in intraocular pressure after pharmacological pupil dilatation in an elderly Chinese population in Taiwan: The Shihpai eye study.

Mydriatic drugs are often used in ophthalmic clinics for pupil dilatation to assess the optic nerve and retina. Clinical studies have indicated that an increase in intraocular pressure (IOP) after pupil dilation is noted in open-angle glaucoma patients, those with narrow angles and in normal subjects. Asians are more likely to have narrow angles. Moreover, age-related cataract may increase the crowdedness of the angle. This study aimed to assess the effects of mydriatic pupil dilatation on IOP in an elderly Chinese population. The Shihpai Eye Study was a community-based, cross-sectional survey of vision and eye diseases among noninstitutionalized subjects aged 65 years and older in Shihpai, Taipei, Taiwan. IOP was taken using noncontact tonometry. The pupil was dilated with 1% tropicamide. IOP was measured again after maximal pupil dilatation 1 hour after mydriasis. Of the 2045 participants, 1361 (66.6%) participated in both the questionnaire and eye examinations. The mean IOP before pupil dilatation was 12.9 ± 3.1 mmHg and was 12.8 ± 3.4 mmHg (range: 5-36 mmHg) after pupil dilatation. IOP higher than 21 mmHg after pupil dilation was noted in 17 (1.34%) participants, of whom IOP exceeded 30 mmHg in two (0.16%). Overall, the changes in IOP before and after pupil dilatation were insignificant ( p = 0.04). In the final regression analyses, refractive status toward hyperopia ( p < 0.01) was the only significant factor associated with an increase in IOP of at least 4 mmHg after pupil dilatation. Our results revealed that the increase in IOP after pharmacological pupil dilatation was minimal, and the incidence of acute angle-closure attack was insignificant. Hyperopic status was the only factor related to an increase in IOP of > 4 mmHg. Caution should be exercised if one is hyperopic or has a history of glaucoma and rechecking IOP in these subjects is suggested after pharmacological mydriasis.

Relationship Between Optical Coherence Tomography and Anterior Chamber Depth After Pupillary Dilation in Primary Angle Closure Suspects.

Anterior chamber depth (ACD) change after pupillary dilation is correlated with lens vault (LV) and anterior chamber width (ACW), as observed by swept-source optical coherence tomography (SS-OCT) at both horizontal and vertical scans in patients with primary angle closure suspect and cataract. The purpose of this study is to evaluate the association between ACD and other anterior chamber parameters after pharmacological dilation in patients with primary angle closure suspect and cataract. SS-OCT was performed for 78 patients at baseline and 1 hour after pharmacological dilation. Measurements were taken at 8 evenly spaced axes at 250, 500, and 750μm from the scleral spur. Pearson correlation coefficient (ρ) was used to evaluate the relationship between averaged ACD change and other SS-OCT parameters. Multivariable regression analyses were performed to determine the parameters that predict ACD change. Across all 14 dimension and angle parameters, 12 parameters at the 270-degree axis and 10 parameters at the 0-degree axis yielded significant correlations with ACD change (ρ=0.24-0.55, P <0.05). Angle parameters were most significantly correlated to ACD change 750µm from the scleral spur. The prediction model for ACD change after pharmacological dilation at 0 degree included decreased LV, wider ACW, and increased trabecular iris space area (all P ≤0.001). The prediction model for ACD change at 270 degrees included: decreased LV, wider ACW, larger change in anterior chamber volume, larger baseline anterior chamber volume, and smaller baseline angle opening distance (all P ≤0.03). LV and ACW, as measured in both vertical and horizontal scans, were found to be determinants of the ACD change after pharmacological pupillary dilation. Examination of these parameters may help identify patients at higher risk of developing angle-closure disease.

Acute Angle-Closure Attacks Are Uncommon in Primary Angle-Closure Suspects after Pharmacologic Mydriasis: The Zhongshan Angle-Closure Prevention Trial

Angle-closure glaucoma is a major cause of blindness worldwide that carries an excessive risk of severe, bilateral visual impairment. A common concern among clinicians is the precipitation of acute angle-closure (AAC) attacks because of mydriasis. We evaluated the risk of AAC after pharmacologic dilation in Chinese individuals classified as having bilateral primary angle-closure suspects (PACSs). Randomized, interventional, controlled trial. A total of 889 patients with bilateral PACSs, aged between 50 and 70 years, were identified through community screening in Guangzhou, China, and enrolled in the study. In the Zhongshan Angle-Closure Prevention Trial, bilateral PACSs were treated with laser peripheral iridotomy (LPI) in 1 randomly selected eye, with the fellow eye serving as an untreated control. Over 72 months of follow-up, the participants had their pupils pharmacologically dilated 6 times with 5% phenylephrine and 0.5% tropicamide. Incidence and risk of post-mydriasis AAC in LPI-treated and untreated, control eyes classified as PACSs. One bilateral AAC attack occurred after mydriasis at the 2-week post-LPI visit. No other AAC events occurred in the LPI-treated eyes. In the untreated eyes, 4 additional attacks occurred: 2 occurred after dilation (1 at 54 months and 1 at 72 months of follow-up) and 2 occurred spontaneously. The risk of post-mydriasis AAC in the untreated eyes was 1 attack in 1587 dilations. The risk of spontaneous AAC in the untreated eyes was 0.44 per 1000 eye-years (95% confidence interval, 0.11-1.77 per 1000 eye-years). The risk of incident AAC attacks in PACSs was extremely low, even in a higher-risk group that underwent repeated pharmacologic pupillary dilation over 6 years of follow-up. Prophylactic LPI reduced this small but real risk. This trial was registered at ISRCTN.com as ISRCTN45213099.

Predicting melatonin suppression by light in humans: Unifying photoreceptor-based equivalent daylight illuminances, spectral composition, timing and duration of light exposure.

Light‐induced melatonin suppression data from 29 peer‐reviewed publications was analysed by means of a machine‐learning approach to establish which light exposure characteristics (ie photopic illuminance, five α‐opic equivalent daylight illuminances [EDIs], duration and timing of the light exposure, and the dichotomous variables pharmacological pupil dilation and narrowband light source) are the main determinants of melatonin suppression. Melatonin suppression in the data set was dominated by four light exposure characteristics: (1) melanopic EDI, (2) light exposure duration, (3) pupil dilation and (4) S‐cone‐opic EDI. A logistic model was used to evaluate the influence of each of these parameters on the melatonin suppression response. The final logistic model was only based on the first three parameters, since melanopic EDI was the best single (photoreceptor) predictor that was only outperformed by S‐cone‐opic EDI for (photopic) illuminances below 21 lux. This confirms and extends findings on the importance of the metric melanopic EDI for predicting biological effects of light in integrative (human‐centric) lighting applications. The model provides initial and general guidance to lighting practitioners on how to combine spectrum, duration and amount of light exposure when controlling non‐visual responses to light, especially melatonin suppression. The model is a starting tool for developing hypotheses on photoreceptors’ contributions to light's non‐visual responses and helps identifying areas where more data are needed, like on the S‐cone contribution at low illuminances.

Effect of Pharmacological Pupil Dilation on Dark-Adapted Perimetric Sensitivity in Healthy Subjects Using an Octopus 900 Perimeter.

PurposeTo determine whether dilation status has a clinically meaningful effect on sensitivity in normal subjects undergoing two-color dark-adapted perimetry, which can be useful to assess rod function.MethodsA perimeter measured naturally and pharmacologically dilated scotopic sensitivities using a test grid consisting of 16 points across the horizontal meridian ranging from 60° temporal to 45° nasal using cyan (500 nm wavelength) or red (650 nm wavelength) stimuli. The primary outcome was average overall sensitivity based on dilation status, which was compared using a linear mixed effect model for each color stimuli. A difference of 2 dB or more was considered clinically significant.ResultsTwenty-nine eyes from 15 subjects (nine female) ages 23 to 63 with no known retinal pathology were included. Pharmacologically dilated eyes were 0.54 dB (95% confidence interval [CI], 0.05 dB to 1.03 dB; P = 0.032) more sensitive to a red stimulus than naturally dilated eyes, but this was not statistically significant after correction for multiple comparisons. Pharmacologically dilated eyes were 0.03 dB (95% CI, −0.20 dB to 0.14 dB; P = 0.734) less sensitive to a cyan stimulus compared to naturally dilated eyes.ConclusionsThese findings show no clinically significant differences in sensitivity of scotopic perimetry in eyes without retinal pathology based on dilation status for both cyan and red stimuli.Translational RelevanceIn this study, pharmacological dilation did not have a clinically meaningful effect on sensitivity, suggesting that this is not necessary when using two-color dark-adapted perimetry to assess for rod function.

Efficacy of a hinged pupil expansion device in small pupil cataract surgery.

Purpose:To evaluate the efficacy and safety of a hinged pupil expansion device (PED) in eyes with small pupils undergoing phacoemulsification.Methods:In this prospective, multicenter, interventional case series of 57 eyes with suboptimal pharmacologic pupil dilation (<5 mm diameter), a hinged PED (I-Ring, Beaver-Visitec International, Waltham, MA) was applied to facilitate surgical visualization during cataract surgery. The pupil diameters (PD) were measured at different stages of the procedure and at the 1-month follow-up visit. Rate of successful intraoperative PED deployment, pupil size, and shape were assessed.Results:The mean patient age was 70.5 ± 12.1 years. The I-Ring PED was successfully applied in all eyes. The mean PD at various stages were 4.1 ± 1.1 mm (dilation with eye drops only preoperatively), 4.3 ± 1.1 mm (dilation after intracameral epinephrine and ophthalmic viscoelastic device), 6.80 ± 0.00 mm (with PED applied), and 5.7 ± 1.1 mm (end of surgery). A statistically significant difference (P < 0.001) was observed between the mean PD with intracameral medications and with PED application. Postoperative circular pupil was observed in 54 of 57 eyes (94.7%) and the mean eccentricity index (n = 57 eyes) was 0.11 ± 0.22. No significant adverse events were observed.Conclusion:The I-Ring PED safely and effectively provided and maintained adequate pupil expansion and surgical visualization in eyes with small pupils undergoing cataract surgery. Postoperatively 95% of eyes attained circular pupils. This hinged PED is an additional instrumentation option for the safe and effective expansion of inadequately sized pupils during cataract surgery.

EFFECT OF PHARMACOLOGICAL PUPIL DILATION ON INTRAOCULAR LENS POWER CALCULATION IN PATIENTS INDICATED FOR CATARACT SURGERY.

To evaluate the influence of pupil dilation on ocular parameters measured by optical biometry and the influence of pupil dilation on intraocular lens (PC IOL) power calculation by using the third-generation (SRK/T) and the fourth-generation (Haigis) formula. 40 eyes of patients indicated for cataract surgery were included in this study. Each patient was examined by optical biometer firstly without artificial mydriasis (AM) and then after AM, which was achieved using local application of short-term acting mydriatics. Biometric data were measured by Lenstar LS 900 optical biometer, we recorded axial length of the eye (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT) and corneal astigmatism and optical power of cornea. These data we measured were used for calculation of the PC IOL optical power using both the SRK/T and the Haigis formula. The target postoperative refraction was set to emmetropia. Statistical analysis was performed for evaluation of influence of AM on each ocular parameter and influence of AM on the recommended PC IOL power calculated by the SRK/T and the Haigis formula. No statistically significant effect of AM on AL, LT and keratometry was demonstrated. On the contrary we demonstrated significant effect on CCT and ACD. No effect of AM on the PC IOL power calculation using the SRK/T formula was proved - the PC IOL optical power before AM and after AM did not differ in any case. When using the Haigis formula for the PC IOL power calculation, the recommended optical power of the PC IOL changed by +0.5 Dpt in 9 eyes, i.e., 22.5% of the whole group, but statistical analysis did not show this change as statistically significant. Pharmacological dilation of the pupil significantly affects some intraocular parameters measured by optical biometer and in the case of using the Haigis formula it can influence recommended power of the PC IOL. Conversely, when using the SRK/T formula, pharmacological dilation of pupil does not affect the recommended PC IOL power.

Telehealth and Screening Strategies in the Diagnosis and Management of Glaucoma.

Telehealth has become a viable option for glaucoma screening and glaucoma monitoring due to advances in technology. The ability to measure intraocular pressure without an anesthetic and to take optic nerve photographs without pharmacologic pupillary dilation using portable equipment have allowed glaucoma screening programs to generate enough data for assessment. At home, patients can perform visual acuity testing, web-based visual field testing, rebound tonometry, and video visits with the physician to monitor for glaucomatous progression. Artificial intelligence will enhance the accuracy of data interpretation and inspire confidence in popularizing telehealth for glaucoma.

Analysis of Iris volume using swept-source optical coherence tomography in patients with type 2 diabetes mellitus.

To evaluate iris volume before and after pupil dilation using swept-source anterior segment optical coherence tomography (SS-ASOCT) and investigate the associated factors of iris volume and iris volume change after pupil dilation in patients with type 2 diabetes mellitus (T2DM). A cross-sectional study was conducted in Zhongshan Ophthalmic Center among T2DM registered patients in the community of Guangzhou, China. Anterior chamber volume (ACV), iris volume, anterior chamber depth (ACD), angle opening distance at 500 μm (AOD 500) and pupil diameter were estimated using SS-ASOCT (CASIA; Tomey, Nagoya, Japan). Venous blood was taken for the measurement of glycosylated haemoglobin A1c (HbAlc). All biometric measurements were performed before and after pharmacologic pupil dilation. A total of 117 subjects were included in the analysis. The mean age (±SD) was 64.96 ± 7.75 years, and 62.4% were females. After pupil dilation, iris volume decreased in all eyes. Shorter duration of diabetes (p = 0.035), longer axial length (p < 0.001) and smaller pupil diameter (p < 0.001) were associated with larger iris volume. The change in iris volume per millimetre change in pupil diameter was 1.35mm3 /mm. Smaller baseline iris volume (p = 0.002) and higher HbA1c level (p = 0.010) were associated with smaller change in iris volume per millimetre change in pupil diameter, after adjusting for other factors. Iris volume can be estimated by SS-ASOCT. Diabetic duration was associated with static anatomy of iris volume, while HbA1c level indicated the dynamic response of iris volume. It is likely that diabetic duration and HbA1c level could affect the macroscopic and microscopic composition of the iris in the diabetic population.

Cost-Effectiveness Analysis of Non-Mydriatic Ultrawide- Field Fundus Photography versus Pharmacological Pupil Dilatation in Diabetic Retinopathy Screening Program

Background: Diabetic retinopathy (DR) causes blindness of the population in many countries worldwide. Early detection and treatment of this disease via a DR screening program is the best way to secure the vision. An annual screening program using pharmacological pupil dilatation becomes the standard method. Recently, non-mydriatic ultrawide-field fundus photography (UWF) has been proposed as a choice for DR screening. However, there was no cost-effectiveness study between the standard DR screening and this UWF approach. Objective: To compare the cost-effectiveness between UWF and pharmacological pupil dilatation in terms of hospital and societal perspectives. Materials and Methods: Patients with type 2 diabetes mellitus that visited the ophthalmology clinic at Chulabhorn Hospital for DR screening were randomized using simple randomization method. The patients were interviewed by a trained interviewer for general and economic information. The clinical characteristics of DR and staging were recorded. Direct medical costs, direct non-medical costs, and informal care costs due to DR screening were recorded. Cost analyses were calculated for the hospital and societal perspectives. Results: The present study presented the cost-effectiveness analyses of UWF versus pharmacological pupil dilatation. Cost-effectiveness analysis from the hospital perspective showed the incremental cost-effectiveness ratio (ICER) of UWF to be –13.87. UWF was a cost-effective mean in DR screening in the societal perspective when compared with pharmacologically pupil dilatation with the ICER of 76.46, under the threshold of willingness to pay. Conclusion: The UWF was a cost-effective mean in DR screening. It can reduce screening duration and bypass post-screening blurred vision. The results suggested that UWF could be a viable option for DR screening. Keywords: Diabetic retinopathy, Diabetic retinopathy screening, Non-mydriatic ultrawide-field fundus photography, Cost-effectiveness analysis

Artificial Intelligence to Detect Papilledema from Ocular Fundus Photographs

BackgroundNonophthalmologist physicians do not confidently perform direct ophthalmoscopy. The use of artificial intelligence to detect papilledema and other optic-disk abnormalities from fundus photographs has not been well studied.MethodsWe trained, validated, and externally tested a deep-learning system to classify optic disks as being normal or having papilledema or other abnormalities from 15,846 retrospectively collected ocular fundus photographs that had been obtained with pharmacologic pupillary dilation and various digital cameras in persons from multiple ethnic populations. Of these photographs, 14,341 from 19 sites in 11 countries were used for training and validation, and 1505 photographs from 5 other sites were used for external testing. Performance at classifying the optic-disk appearance was evaluated by calculating the area under the receiver-operating-characteristic curve (AUC), sensitivity, and specificity, as compared with a reference standard of clinical diagnoses by neuro-ophthalmologists.ResultsThe training and validation data sets from 6779 patients included 14,341 photographs: 9156 of normal disks, 2148 of disks with papilledema, and 3037 of disks with other abnormalities. The percentage classified as being normal ranged across sites from 9.8 to 100%; the percentage classified as having papilledema ranged across sites from zero to 59.5%. In the validation set, the system discriminated disks with papilledema from normal disks and disks with nonpapilledema abnormalities with an AUC of 0.99 (95% confidence interval [CI], 0.98 to 0.99) and normal from abnormal disks with an AUC of 0.99 (95% CI, 0.99 to 0.99). In the external-testing data set of 1505 photographs, the system had an AUC for the detection of papilledema of 0.96 (95% CI, 0.95 to 0.97), a sensitivity of 96.4% (95% CI, 93.9 to 98.3), and a specificity of 84.7% (95% CI, 82.3 to 87.1).ConclusionsA deep-learning system using fundus photographs with pharmacologically dilated pupils differentiated among optic disks with papilledema, normal disks, and disks with nonpapilledema abnormalities. (Funded by the Singapore National Medical Research Council and the SingHealth Duke–NUS Ophthalmology and Visual Sciences Academic Clinical Program.)