Pharmacologic Dilation Research Articles

Systematic review: Can non-mydriatic cameras accurately detect diabetic retinopathy?

Diabetes puts many individuals at risk for developing diabetic retinopathy (DR). Non-mydriatic (NM) retinal photography without pharmacological pupil dilation can be used to detect DR, however, its value in a general clinical setting has not been established. The objective of this review is to evaluate the validity of NM retinal photos, as compared to the reference standard of seven standard stereoscopic 30 degree field photographs (7SF), for their use of detecting DR in community-dwelling adults. English articles were identified through MEDLINE (1992-2016), EMBASE (1992-2016), Center for Disease Control and Prevention, Food and Drug Administration, Health Canada, and Google Scholar (1992-2016). Only studies that examined the validity of NM retinal photos, without pharmacological pupil dilation, as compared to 7SF, used in a community-dwelling adult population were included. Risk of bias was assessed using the QUADAS-2. Of the 368 articles identified in the search, 6 articles met eligibility requirements. Sensitivities ranged from 64 to 97.9% and specificities ranged from 65.6 to 98%. Studies that used multiple field images to detect DR in a younger population generally produced higher quality photos and more valid results. The strongest validity indicators were reported in studies capturing multiple field images.

Morphologic Patterns Formed by the Anomalous Fibers Occurring Along the Anterior Capsule of the Crystalline Lens in People With the Long Anterior Zonule Trait

People with the long anterior zonule (LAZ) trait, which may have prevalence near 2%, have zonular fibers that extend more central than usual along the anterior capsule of the crystalline lens. The anomalous fibers can be observed in vivo with clinical slit lamp biomicroscopy after pharmacologic pupil dilation, and although minimally studied, the LAZ trait may have importance to glaucoma, retinal degeneration, and cataract surgery. To further characterize LAZ morphology, a custom computer program was used to trace LAZ fibers seen on retro-illumination photos acquired during previous study at an academic, urban eye care facility in Chicago, IL. There were 59 African-Americans (54 female; median age = 70 years, 53-91 years) included in the analysis. After initial review of the zonule tracings, we identified three basic LAZ patterns. We called one pattern (47% of right eyes) a "non-segmental LAZ pattern," which was predominated by fibers that could be visually traced to the dilated pupil border where they became obscured by the iris. Another pattern (35% of right eyes), the "segmental LAZ pattern," was predominated by fibers that appeared to terminate abruptly without detectable extension to the pupil border. The third pattern (18% of right eyes), the "mixed LAZ pattern," had a more equivalent mixture of the other two fiber morphologies. Compared to the "non-segmental" group, the "segmental" LAZ eyes had smaller central zonule-free zones (P < 0.0001), and they tended to exhibit fewer LAZ fibers (P = 0.07). These data improve understanding of LAZ clinical anatomy and may be helpful to future investigation. Anat Rec, 300:1336-1347, 2017. © 2017 Wiley Periodicals, Inc.

A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer.

Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm × 91mm × 45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

Ocular Blood Flow Measurements in Healthy White Subjects Using Laser Speckle Flowgraphy.

PurposeTo assess the feasibility and reliability of Laser Speckle Flowgraphy (LSFG) to measure ocular perfusion in a sample of healthy white subjects and to elucidate the age-dependence of the parameters obtained.MethodsThis cross-sectional study included 80 eyes of 80 healthy, non-smoking white subjects of Western European descent between 19 and 79 years of age. A commercial LSFG instrument was applied to measure ocular blood flow at the optic nerve head (ONH) three successive times before and after pharmacological pupil dilation. The mean blur rate (MBR), a measure of relative blood flow velocity, was obtained for different regions of the ONH. Eight parameters of ocular perfusion derived from the pulse-waveform analysis of MBR including blowout time (BOT) and falling rate (FR) were also recorded.ResultsArtifact-free LSFG images meeting the quality criteria for automated image analysis were obtainable in 93.8% without pupil dilation and in 98.8% with pharmacological pupil dilation. Measurements of MBR showed excellent repeatability with intraclass correlation coefficients ≥ 0.937 and were barely affected by pupil dilation. The majority of pulse-waveform derived variables exhibited equally high repeatability. MBR-related blood flow indices exhibited significant age dependence (p<0.001). FR (r = 0.747, p<0.001) and BOT (r = -0.714, p<0.001) most strongly correlated with age.ConclusionsLSFG represents a reliable method for the quantitative assessment of ocular blood flow in white subjects. Our data affirms that the LSFG-derived variables FR and BOT may be useful biomarkers for age-related changes in ocular perfusion.

Screening of intraocular pressure before routine pupil dilation for retinal photography: Clinical case report

Introduction Pharmacologic dilation of the pupil results in twice the sensitivity of detection of diabetic retinopathy compared with undilated retinal examination. The potential risk of acute angle-closure glaucoma after pupil dilation has been hypothesized to be higher in Asian patients with diabetes mellitus. Clinical case A 61-year-old man with diabetes mellitus and hypertension was incidentally found to have elevated intraocular pressure (IOP) before routine retinal photography. He was asymptomatic and the visual acuity was 0.67 for both eyes. An ophthalmologist later found he had anatomical narrow-angle borderline glaucoma. Topical administration of pilocarpine and oral administration of acetazolamide were initiated, and laser iridotomy was later performed. IOP screening Among 1736 diabetic and/or hypertensive patients who underwent IOP screening, 31 patients (1.8%) had IOP of any eye persistently higher than 21 mm Hg on at least two occasions. The mean (standard deviation) IOP of the right eye was 24.1 (2.1) mm Hg, while that of the left eye was 24.6 (2.5) mm Hg. Four patients (12.9%) were found to have glaucoma, and treatment was initiated by an ophthalmologist. Therefore further study should be conducted to evaluate the cost-effectiveness of IOP screening among this group of patients.

Effect of pharmacological pupil dilation on measurements and iol power calculation made using the new swept-source optical coherence tomography-based optical biometer

To determine whether pupil dilation affects biometric measurements and intraocular lens (IOL) power calculation made using the new swept-source optical coherence tomography-based optical biometer (IOLMaster 700©; Carl Zeiss Meditec, Jena, Germany). Eighty-one eyes of 81 patients evaluated for cataract surgery were prospectively examined using the IOLMaster 700© before and after pupil dilation with tropicamide 1%. The measurements made were: axial length (AL), central corneal thickness (CCT), aqueous chamber depth (ACD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW) and pupil diameter (PD). Holladay II and SRK/T formulas were used to calculate IOL power. Agreement between measurement modes (with and without dilation) was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots. Mean patient age was 75.17±7.54 years (range: 57-92). Of the variables determined, CCT, ACD, LT and WTW varied significantly according to pupil dilation. Excellent intraobserver correlation was observed between measurements made before and after pupil dilation. Mean IOL power calculation using the Holladay 2 and SRK/T formulas were unmodified by pupil dilation. The use of pupil dilation produces statistical yet not clinically significant differences in some IOLMaster 700© measurements. However, it does not affect mean IOL power calculation.

Individual Differences in the Post-Illumination Pupil Response to Blue Light: Assessment without Mydriatics.

Melanopsin-containing retinal ganglion cells play an important role in the non-image forming effects of light, through their direct projections on brain circuits involved in circadian rhythms, mood and alertness. Individual differences in the functionality of the melanopsin-signaling circuitry can be reliably quantified using the maximum post-illumination pupil response (PIPR) after blue light. Previous protocols for acquiring PIPR relied on the use of mydriatics to dilate the light-exposed eye. However, pharmacological pupil dilation is uncomfortable for the participants and requires ophthalmological expertise. Hence, we here investigated whether an individual’s maximum PIPR can be validly obtained in a protocol that does not use mydriatics but rather increases the intensity of the light stimulus. In 18 participants (5 males, mean age ± SD: 34.6 ± 13.6 years) we evaluated the PIPR after exposure to intensified blue light (550 µW/cm2) provided to an undilated dynamic pupil. The test-retest reliability of the primary PIPR outcome parameter was very high, both between day-to-day assessments (Intraclass Correlation Coefficient (ICC) = 0.85), as well as between winter and summer assessments (ICC = 0.83). Compared to the PIPR obtained with the use of mydriatics and 160 µW/cm2 blue light exposure, the method with intensified light without mydriatics showed almost zero bias according to Bland-Altman plots and had moderate to strong reliability (ICC = 0.67). In conclusion, for PIPR assessments, increasing the light intensity is a feasible and reliable alternative to pupil dilation to relieve the participant’s burden and to allow for performance outside the ophthalmological clinic.

Fundus photography with a smartphone in indirect ophthalmoscopy in dogs and cats.

To introduce a simple method for fundus photography of dogs and cats using a smartphone and indirect ophthalmoscopy lenses. Fundus photographs of dogs and cats with transparent ocular media were obtained with 15D, 20D, 28D, and 40D indirect lenses and an iPhone-6, in a dark room and after pharmacologic pupil dilation. The photographs were recorded as still images using a video application and a video-to-still image application. Two types of neutral density (ND) filters were used as required for reduction of the torch illumination power of the iPhone. The images obtained in this study were upside-down as a result of the optics used. A 180-degree rotation was used to show their natural anatomical orientation. The image field of view varied with the diopter strength of the indirect lens used. The 40-diopter lens offered the widest field. Still images obtained with a smartphone, and indirect lenses may be useful for client communication and teaching in small animal ophthalmology.

Hookah Smoking Does Not Constrict Human Coronary Microvessels

Hookah (water pipe) smoking has reached epidemic proportions due to unregulated social media marketing to young adults as a safer avant‐garde alternative to cigarettes. In contrast, much is suspected by tobacco researchers—yet little is proven—about hookah's putative health risks. What distinguishes hookah from all other tobacco products is that burning charcoal is used to heat the tobacco. As a result, hookah smoke delivers a large acute exposure not only to carbon monoxide (CO) but also to fine and ultrafine particles, charcoal combustion products that have been suggested—but unproven—by the air pollution and tobacco literature to constitute putative coronary vasoconstrictor stimuli. To test if hookah smoking constricts human coronary microvessels, in 28 young adult hookah smokers (age 27±5 years, mean±SD, 8 women, 20 men) we used myocardial contrast echocardiography (MCE) perfusion imaging with intravenous lipid shelled microbubbles to measure myocardial blood flow and its two components, microvascular flux rate (β) and functional capillary blood volume (A), and measured myocardial oxygen consumption (MVO2 = (7.2 × 10−4) x (heart rate x systolic blood pressure) + 1.42) as well as exhaled CO and plasma nicotine before and immediately after 30 minutes of ad lib hookah smoking in a custom‐built smoking chamber. With hookah smoking, exhaled CO increased from 3.0±0.4 to 25±2.2 ppm (mean ±SE, p&lt;0.001 pre‐vs. post‐hookah), which approximates the CO boost of a typical ad lib hookah smoking session in hookah bars and indicates an exposure to fine and ultrafine particles that is 10 times greater (and to total particles that is 250 times greater) than that with cigarette smoking. On MCE, myocardial blood flow (A x β) did not decrease but rather increased acutely with hookah smoking (88±10 to 120±19 a.u.·s−1, p=0.02). The increased perfusion matched the mild hookah‐induced increase in MVO2 (6.5±0.3 to 7.6±0.4 ml·min−1, p&lt;0.001), indicating physiologic vasodilation, and was manifested primarily by increased microvascular flux rate (0.7±0.1 to 0.9±0.1 s−1, p=0.01) with unchanged capillary blood volume (133±7 to 137±7 a.u., p=ns), a pattern of coronary microvascular response seen previously with a mild b‐adrenergic agonist. Moreover, the increased MVO2 and accompanying decrease in heart rate variability were accompanied by increased plasma nicotine (0.9±0.1 to 7.8±1.3 mg/mL, p&lt;0.001) and almost completely eliminated by intravenous propranolol, documenting b‐adrenergic mediation. Thus, under these experimental conditions, mainstream hookah smoke either is not an acute coronary vasoconstrictor stimulus or one that is too weak to overcome the physiologic dilation of coronary microvessels caused by mild nicotine‐induced cardiac b‐adrenergic stimulation and/or pharmacologic dilation caused by carbon monoxide.

Diabetic retinopathy screening with pharmacy-based teleophthalmology in a semiurban setting: a cost-effectiveness analysis.

Diabetic eye complications are the leading cause of visual loss among working-aged people. Pharmacy-based teleophthalmology has emerged as a possible alternative to in-person examination that may facilitate compliance with evidence-based recommendations and reduce barriers to specialized eye care. The objective of this study was to estimate the cost-effectiveness of mobile teleophthalmology screening compared with in-person examination (primary care) for the diabetic population residing in semiurban areas of southwestern Ontario. A decision tree was constructed to compare in-person examination (comparator program) versus pharmacy-based teleophthalmology (intervention program). The economic model was designed to identify patients with more than minimal diabetic retinopathy, manifested by at least 1 microaneurysm at examination (modified Airlie House classification grade of ≥ 20). Cost-effectiveness was assessed as cost per case detected (true-positive result) and cost per case correctly diagnosed (including true-positive and true-negative results). The cost per case detected was $510 with in-person examination and $478 with teleophthalmology, and the cost per case correctly diagnosed was $107 and $102 respectively. The incremental cost-effectiveness ratio was $314 per additional case detected and $73 per additional case correctly diagnosed. Use of pharmacologic dilation and health care specialists' fees were the most important cost drivers. The study showed that a compound teleophthalmology program in a semiurban community would be more effective but more costly than in-person examination. The findings raise the question of whether the benefits of pharmacy-based teleophthalmology in semiurban areas, where in-person examination is still available, are equivalent to those observed in remote communities. Further study is needed to investigate the impact of this program on the prevention of severe vision loss and quality of life in a semiurban setting.

Prevalence of undiagnosed diabetic retinopathy among inpatients with diabetes: the diabetic retinopathy inpatient study (DRIPS)

ObjectiveTo determine the prevalence and risk factors of diabetic retinopathy in the inpatient diabetic population in the USA and to determine the barriers to ophthalmic examinations and treatment among this...

Retinal Imaging Techniques for Diabetic Retinopathy Screening.

Due to the increasing prevalence of diabetes mellitus, demand for diabetic retinopathy (DR) screening platforms is steeply increasing. Early detection and treatment of DR are key public health interventions that can greatly reduce the likelihood of vision loss. Current DR screening programs typically employ retinal fundus photography, which relies on skilled readers for manual DR assessment. However, this is labor-intensive and suffers from inconsistency across sites. Hence, there has been a recent proliferation of automated retinal image analysis software that may potentially alleviate this burden cost-effectively. Furthermore, current screening programs based on 2-dimensional fundus photography do not effectively screen for diabetic macular edema (DME). Optical coherence tomography is becoming increasingly recognized as the reference standard for DME assessment and can potentially provide a cost-effective solution for improving DME detection in large-scale DR screening programs. Current screening techniques are also unable to image the peripheral retina and require pharmacological pupil dilation; ultra-widefield imaging and confocal scanning laser ophthalmoscopy, which address these drawbacks, possess great potential. In this review, we summarize the current DR screening methods using various retinal imaging techniques, and also outline future possibilities. Advances in retinal imaging techniques can potentially transform the management of patients with diabetes, providing savings in health care costs and resources.

Association between Grapes Intake and Diabetic Retinopathy: Inhibitory Effect of Resveratol on Diabetic Retinopathy

Purpose: To evaluate the association between grape intake and diabetic retinopathy. Methods: A population-based cross-sectional study using a nation-wide, stratified, multistage, clustered sampling method included 1,555 subjects aged ≥30 years who participated in the Korean National Health and Nutritional Examination Survey 2008-2011. All participants performed standardized interviews, food frequency questionnaires (FFQ), and comprehensive ophthalmic examinations. Grape intake was evaluated by an FFQ using 10 intervals of average frequency of grape intake during the past year. Diabetic retinopathy (DR) was evaluated by 7 standard retinal fundus photographs after pharmacological pupil dilatation. DR was classified as any DR, proliferative DR, or vision-threatening DR by the modified Air House classification system. Results: The prevalence of diabetes was 16.9 ± 1.2%. As the grape intake frequency increases in FFQ, the odds ratio (OR) for any DR, proliferative DR, and vision-threatening DR were 0.86 (95% confidence interval [CI], 0.75-0.98), 0.65 (95% CI, 0.48-0.88), and 0.77 (95% CI, 0.60-0.99) respectively. Compared to the group with a grape intake of less than once per month, the OR for any DR, proliferative DR, and vision-threatening DR in the group with a grape intake of more than 2-3 times per month were 0.54 (95% CI 0.33-0.89), 0.25 (95% CI 0.07-0.81), 0.36 (95% CI 0.13-0.95), respectively. Conclusions: The intake of grapes was inversely associated with the prevalence of DR. J Korean Ophthalmol Soc 2016;57(2):276-282

Red Reflex-Guided Big-Bubble Deep Anterior Lamellar Keratoplasty: A Simple Technique to Judge Dissection Depth.

To report the results of a modified big-bubble deep anterior lamellar keratoplasty technique using the intraoperative red reflex to visualize the amount of residual stroma beneath the inserted cannula. A total of 132 consecutive keratoconic eyes were included in this retrospective, noncomparative, interventional case series. Before starting surgery, pharmacologic mydriasis was induced in all eyes undergoing a big-bubble deep anterior lamellar keratoplasty procedure. After partial trephination of the recipient cornea, a spatula was inserted at the base of the incision and advanced into depth using as a reference the thin dark line seen in the red reflex ahead of the advancing tip; the stromal depth reached was measured using anterior segment optical coherence tomography. Finally, the spatula was exchanged for a 27-gauge cannula, and air was injected to create a big bubble. The stromal depth reached with the spatula, success rate of big-bubble formation, and complications were recorded. The big bubble was obtained in 118 of 132 eyes (89.4%). Of the remaining 14 eyes, 11 underwent completion of the procedure by manual dissection and 3 were converted to penetrating keratoplasty because the bubble burst while trying to enlarge it. Perforation did not occur in any case during cannula insertion. The average thickness reached with the stromal dissection was 64.3 ± 19.5 μm. The thin dark line, seen in the red reflex obtained with pharmacologic dilation, provides a useful and effective reference that can be used to visualize and judge the depth of dissection, thus allowing a safer and reproducible approach to the pre-Descemetic stroma.

Fractional flow reserve: physiological basis, advantages and limitations, and potential gender differences.

Fractional flow reserve (FFR) is a physiological index of the severity of a stenosis in an epicardial coronary artery, based on the pressure differential across the stenosis. Clinicians are increasingly relying on this method because it is independent of baseline flow, relatively simple, and cost effective. The accurate measurement of FFR is predicated on maximal hyperemia being achieved by pharmacological dilation of the downstream resistance vessels (arterioles). When the stenosis causes FFR to be impaired by > 20%, it is considered to be significant and to justify revascularization. A diminished hyperemic response due to microvascular dysfunction can lead to a false normal FFR value, and a misguided clinical decision. The blunted vasodilation could be the result of defects in the signaling pathways modulated (activated or inhibited) by the drug. This might involve a downregulation or reduced number of vascular receptors, endothelial impairment, or an increased activity of an opposing vasoconstricting mechanism, such as the coronary sympathetic nerves or endothelin. There are data to suggest that microvascular dysfunction is more prevalent in post-menopausal women, perhaps due to reduced estrogen levels. The current review discusses the historical background and physiological basis for FFR, its advantages and limitations, and the phenomenon of microvascular dysfunction and its impact on FFR measurements. The question of whether it is warranted to apply gender-specific guidelines in interpreting FFR measurements is addressed.

The association between chronic kidney disease and diabetic retinopathy: the Korea National Health and Nutrition Examination Survey 2008-2010.

PurposeTo explore the relationship between chronic kidney disease and diabetic retinopathy in a representative population of Korean diabetic adults.MethodsWe analyzed data from the Korea National Health and Nutrition Examination Surveys (2008-2010). A total of 15,409 individuals (weighted frequency, 32,168,636) aged 19 and over who completed ophthalmologic and renal functional examinations were evaluated. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate of < 60 ml/min/1.73 m2 or proteinuria greater than 1+. Seven standard photographs from the Early Treatment for Diabetic Retinopathy Study were obtained from each eye after pharmacological pupil dilatation. Diabetic retinopathy (DR) was defined as the presence of 1 or more retinal microaneurysms or retinal blot hemorrhages with or without more severe lesions. Vision-threatening diabetic retinopathy (VTDR) was defined as the presence of a clinically significant macular edema (CSME) or proliferative diabetic retinopathy.ResultsCKD was significantly associated with DR and VTDR (odds ratio (OR), 95% confidence interval (CI); 2.49(1.43-4.35) and 3.74(1.56-8.95), respectively) in the diabetic population. After controlling for confounders, however, CKD was significantly associated only with DR [adjusted OR (aOR), 95% CI; 2.34(1.04-5.28)]. In the subgroup analysis for CKD, only proteinuria was significantly associated with DR and VTDR (aOR, 95% CI; 4.56(1.51-13.77) and 5.61(1.06-29.87), respectively) in this population.ConclusionsOur results show that CKD appears to be associated with DR and VTDR in a Korean diabetic population. In particular, proteinuria, not decreased eGFR, is more significantly associated with DR or VTDR.

Efectos de la midriasis farmacológica en la medida de la profundidad de la cámara anterior con IOL Master y Sirius

This study aims to analyze the influence of pharmacological pupillary dilation in the anterior chamber depth (ACD) and anterior chamber angle (ACA) measured with IOL Master and Sirius. A total of 99 eyes of 50 patients were included in the sample with an age range of 15-78. 24 of them were induced with cyclopentolate 1% and 75 with tropicamide 1% and phenylephrine 10%. ACD was measured with IOL Master and ACD, ACA and pachymetry with Sirius. All the analyzed variables were statistically significant (P<0.05) except pachymetry. IOL Master measurements of ACD increased 0.068 ± 0.007 mm on average after pupillary dilatation. However, a narrowing of the anterior chamber (AC) of 0.078 ± 0.031 mm on average was found. A good correlation between Sirius and IOL Master pre dilation measures was found. The AC increased 10.92 ± 0.87 degrees on average after dilation of the pupil. There are significant differences in the ACD measured with IOL Master and Sirius before and after topical application of mydriatics and cycloplegics drugs in the eye, those differences are statistically but not clinically significant. The ACA also varied significantly. More studies are necessary in order to check the repeatability and reliability of Scheimpflug technology devices on dilated eyes.

Effect of pupil dilation on biometry measurements with partial coherence interferometry and its effect on IOL power formula calculation.

To determine if there are any differences between eye parameters measured by the IOLMaster (Carl Zeiss Meditec AG, Jena, Germany) biometer before and after dilating the pupil. The effect of those changes on intraocular lens (IOL) power calculation is also analyzed. A prospective observational study was carried out including 107 right eyes of 107 patients with cataract and no other ocular morbidity. An IOLMaster baseline measurement included axial length (AL), mean keratometry (K), and anterior chamber depth (ACD) (corneal epithelium to lens). A second measurement was taken 45 minutes after instillation of topical tropicamide and phenylephrine. Biometric variation was analyzed and prediction for IOL power based on the Haigis and the Sanders/Retzlaff/Kraff Theoretical (SRK/T) formulas was calculated for both measurements. The ACD increased significantly after dilation (+0.12 ± 0.12 mm; p&lt;0.01). The AL and K variation was not significant: +0.00 ± 0.02 mm (p = 0.62) and +0.01 ± 0.22 D (p = 0.57), respectively. Pupil dilation did not affect IOL power calculation based on SRK/T formula either targeting emmetropia (-0.02 ± 0.26, p = 0.30) or the lowest myopic residual refraction (-0.03 ± 0.34, p = 0.30). However, using the Haigis formula significantly changed calculations for emmetropia (0.07 ± 0.34, p = 0.03) and for the lowest myopic refraction (0.10 ± 0.40, p = 0.01). Pupil pharmacologic dilation produces a significant increase in ACD when measured by the IOLMaster. This change results in a different IOL power prediction according to the Haigis formula, which calculates the effective lens position taking into account the ACD.

Comparison of Physiologic versus Pharmacologic Mydriasis on Anterior Chamber Angle Measurements Using Spectral Domain Optical Coherence Tomography.

Purpose. To compare the effects of physiologic versus pharmacologic pupil dilation on anterior chamber angle (ACA) measurements obtained with spectral domain optical coherence tomography (SD-OCT). Methods. Forty eyes from 20 healthy, phakic individuals with open angles underwent anterior segment OCT imaging under 3 pupillary states: (1) pupil constricted under standard room lighting, (2) physiologic mydriasis in a darkened room, and (3) postpharmacologic mydriasis. Inferior angle Schwalbe's line-angle opening distance (SL-AOD) and SL-trabecular-iris-space area (SL-TISA) were computed for each eye and pupillary condition by masked, certified Reading Center graders using customized grading software. Results. SL-AOD and SL-TISA under pupillary constriction to room light were 0.87 ± 0.31 mm and 0.33 ± 0.14 mm2, respectively; decreased to 0.75 ± 0.29 mm (P < 0.01) and 0.29 ± 0.13 mm2 (P < 0.01), respectively, under physiologic mydriasis; and increased to 0.90 ± 0.38 mm (P < 0.01) and 0.34 ± 0.17 mm2 (P = 0.06) under pharmacologic mydriasis compared to baseline. Conclusions. Using SD-OCT imaging, pharmacologic mydriasis yielded the widest angle opening, whereas physiologic mydriasis yielded the most angle narrowing in normal individuals with open iridocorneal angles. Accounting for the state of the pupil and standardizing the lighting condition would appear to be of importance for future studies of the angle.

Determinants of anterior chamber angle narrowing after mydriasis in the patients with cataract

To identify the determinants of anterior chamber angle narrowing after mydriasis by quantitative assessment of the anterior chamber components using anterior segment optical coherence tomography (AS-OCT). In this intervention study, anterior chamber angle analysis was performed using AS-OCT in patients with cataract before pharmacological pupillary dilation and 30min afterwards. Angle narrowing was quantified by the change of angle opening distance 500 after mydriasis (ΔAOD500). Multivariate linear regression and stepwise selection regression were used to identify which parameters in AS-OCT significantly determined ΔAOD500. One hundred and two Japanese patients (age, mean ± standard deviation, 71.9 ± 11.2years) were enrolled. Multivariate analysis indicated that smaller ΔAOD500 were significantly associated with larger lens vault (LV; P < 0.001), larger iris area (IA; P = 0.003), and posterior corneal arch distance (PCAL; P = 0.01). Stepwise linear regression analysis revealed that smaller ΔAOD500 was independently associated with larger LV (partial R (2) = 0.232, P < 0.001), larger IA (partial R (2) = 0.080, P = 0.001), and smaller PCAL (partial R (2) = 0.066, P = 0.002) before mydriasis. These three factors explained 37.7% of the decrease in ΔAOD500. Larger LV, larger IA, and smaller PCAL contribute considerably to anterior chamber angle narrowing after mydriasis in patients with cataract.