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Kim D, Park SE, Hwang J, Kang N, Jung JS, Park KM. Ultrasound biomicroscopy analysis of ciliary muscle dynamics and its relation to intra-ocular pressure after phacoemulsification in dogs. Front Vet Sci 2024; 11:1366997. [PMID: 38784657 PMCID: PMC11111888 DOI: 10.3389/fvets.2024.1366997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction This study investigates the relationship between ciliary muscle dynamics, thickness, and the regulation of intraocular pressure (IOP), focusing on the progression of cataracts and changes post-phacoemulsification. It explores how these factors impact canine ocular health, particularly in the context of cataract development and subsequent surgical intervention. Materials and methods Data was collected using Ultrasound Biomicroscopy (UBM) from dogs at the Veterinary Medical Teaching Hospital of Chungbuk National University, Korea. The study involved 57 eyes from 35 dogs, categorized into five groups: 13 normal eyes, 14 with incipient cataracts, 12 with immature cataracts, 6 with mature cataracts, and 12 post-phacoemulsification. UBM measurements assessed various ciliary muscle parameters including ciliary body axial length (CBAXL), ciliary process-sclera angle (CPSA), longitudinal fibers of ciliary muscle thickness (Lf-CMT), and longitudinal and radial fibers of ciliary muscle thickness (LRf-CMT). Results Findings indicated a decrease in CBAXL and an increase in Lf-CMT as cataracts progressed in severity. Post-phacoemulsification, there was a notable increase in CBAXL and a decrease in CPSA, Lf-CMT, and LRf-CMT, compared to both cataractous and normal eyes. Regression analysis revealed a significant positive association between CBAXL and IOP, alongside a negative association between Lf-CMT and IOP. These findings suggest that variations in ciliary muscle dynamics and thickness, as influenced by cataract progression and phacoemulsification, have distinct impacts on intraocular pressure. Discussion The study proposes that phacoemulsification leads to ciliary muscle contraction, causing an inward and anterior movement of the ciliary muscle. This movement results in the narrowing of the ciliary cleft and constriction of the unconventional outflow pathway, potentially causing an increased risk of glaucoma post-surgery. Our research contributes to understanding the anatomical and physiological changes in the canine eye following cataract surgery and underscores the importance of monitoring IOP and ciliary muscle dynamics in these patients.
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Affiliation(s)
| | | | | | | | | | - Kyung-Mee Park
- Laboratory of Veterinary Surgery and Ophthalmology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
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Durkee H, Ruggeri M, Rohman L, Williams S, Ho A, Parel JM, Manns F. Dynamic refraction and anterior segment OCT biometry during accommodation. BIOMEDICAL OPTICS EXPRESS 2024; 15:2876-2889. [PMID: 38855690 PMCID: PMC11161352 DOI: 10.1364/boe.512193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 06/11/2024]
Abstract
Accommodation is the process by which the eye changes focus. These changes are the result of changes to the shape of the crystalline lens. Few prior studies have quantified the relation between lens shape and ocular accommodation, primarily at discrete static accommodation states. We present an instrument that enables measurements of the relation between changes in lens shape and changes in optical power continuously during accommodation. The system combines an autorefractor to measure ocular power, a visual fixation target to stimulate accommodation, and an optical coherence tomography (OCT) system to image the anterior segment and measure ocular distances. Measurements of ocular dimensions and refraction acquired dynamically on three human subjects are presented. The individual accommodative responses are analyzed to correlate the ocular power changes with changes in ocular dimensions.
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Affiliation(s)
- Heather Durkee
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
| | - Marco Ruggeri
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
| | - Leana Rohman
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
| | - Siobhan Williams
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
| | - Arthur Ho
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
- Brien Holden Vision Institute Limited, Sydney, NSW, Australia
- School of Optometry and Vision Science, University of New South Wales, NSW 2052, Sydney, Australia
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
- Brien Holden Vision Institute Limited, Sydney, NSW, Australia
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Department of
Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10 Ave, Miami, Florida 33136, USA
- Department of Biomedical Engineering, University of Miami College of Engineering, 1251 Memorial Drive, Coral Gables, Florida 33146, USA
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Straßer T, Wagner S. Performance of the Deep Neural Network Ciloctunet, Integrated with Open-Source Software for Ciliary Muscle Segmentation in Anterior Segment OCT Images, Is on Par with Experienced Examiners. Diagnostics (Basel) 2022; 12:diagnostics12123055. [PMID: 36553062 PMCID: PMC9777151 DOI: 10.3390/diagnostics12123055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/24/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022] Open
Abstract
Anterior segment optical coherence tomography (AS-OCT), being non-invasive and well-tolerated, is the method of choice for an in vivo investigation of ciliary muscle morphology and function. The analysis requires the segmentation of the ciliary muscle, which is, when performed manually, both time-consuming and prone to examiner bias. Here, we present a convolutional neural network trained for the automatic segmentation of the ciliary muscle in AS-OCT images. Ciloctunet is based on the Freiburg U-net and was trained and validated using 1244 manually segmented OCT images from two previous studies. An accuracy of 97.5% for the validation dataset was achieved. Ciloctunet's performance was evaluated by replicating the findings of a third study with 180 images as the test data. The replication demonstrated that Ciloctunet performed on par with two experienced examiners. The intersection-over-union index (0.84) of the ciliary muscle thickness profiles between Ciloctunet and an experienced examiner was the same as between the two examiners. The mean absolute error between the ciliary muscle thickness profiles of Ciloctunet and the two examiners (35.16 µm and 45.86 µm) was comparable to the one between the examiners (34.99 µm). A statistically significant effect of the segmentation type on the derived biometric parameters was found for the ciliary muscle area but not for the selective thickness reading ("perpendicular axis"). Both the inter-rater and the intra-rater reliability of Ciloctunet were good to excellent. Ciloctunet avoids time-consuming manual segmentation, thus enabling the analysis of large numbers of images of ample study cohorts while avoiding possible examiner biases. Ciloctunet is available as open-source.
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Affiliation(s)
- Torsten Straßer
- Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany
- University Eye Hospital Tuebingen, 72076 Tuebingen, Germany
- Correspondence:
| | - Sandra Wagner
- Institute for Ophthalmic Research, University of Tuebingen, 72076 Tuebingen, Germany
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Mitsukawa T, Suzuki Y, Momota Y, Suzuki S, Yamada M. Anterior Segment Biometry During Accommodation and Effects of Cycloplegics by Swept-Source Optical Coherence Tomography. Clin Ophthalmol 2020; 14:1237-1243. [PMID: 32440090 PMCID: PMC7213076 DOI: 10.2147/opth.s252474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/21/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose We analyzed changes in the crystalline lens during accommodation and the effects of cycloplegics by swept-source anterior-segment optical coherence tomography (AS-OCT). Materials and Methods Twenty healthy volunteers (7 males and 13 females, aged 22–34 years), with no history of eye disease except for refractive errors, were recruited. Biometric parameters, including anterior chamber depth (ACD), lens thickness (LT), and anterior and posterior curvature of the lens (ACL and PCL), were measured using AS-OCT (CASIA2). The measurements were performed with or without an accommodative demand of 5.0 diopters (D). The same tests were repeated following the topical administration of 1% cyclopentolate or a compounding agent comprising 0.5% tropicamide and 0.5% phenylephrine. Results The AS-OCT system was capable of simultaneous visualization of all optical components of the anterior segment in a single frame. ACD, LAC, and LPC decreased and LT increased significantly during 5.0 D accommodative stimulation in both eyes. Both cyclopentolate and tropicamide/phenylephrine eyedrops led to deeper ACD, thinner LT, and flatter LAC. There were no significant differences in all lens parameters despite having 5.0 D accommodative stimulation in both eyes with cycloplegia. Conclusion Our results suggest that both tropicamide/phenylephrine and cyclopentolate eyedrops have enough cycloplegic effects in young adults.
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Affiliation(s)
- Tadahiro Mitsukawa
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Yumi Suzuki
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Yosuke Momota
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Shun Suzuki
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Masakazu Yamada
- Department of Ophthalmology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
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Bullimore MA, Richdale K. Myopia Control 2020: Where are we and where are we heading? Ophthalmic Physiol Opt 2020; 40:254-270. [DOI: 10.1111/opo.12686] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/20/2020] [Accepted: 03/24/2020] [Indexed: 12/16/2022]
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Ocak OB, Inal A, Tülü Aygün B, Kırmacı Kabakci A, Kemer Atik B, Yurttaser Ocak S, Gökyiğit B. Refraction under general anesthesia in children, using cycloplegic refraction only as a reference. Strabismus 2020; 28:73-78. [PMID: 31985321 DOI: 10.1080/09273972.2020.1714669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To compare the measurements of cycloplegic refraction and refraction (R1-1) under general anesthesia (GA) when using the same portable auto-refractometer (ARF) in pediatric patients. METHODS 36Thirty-six to 60-month-old patients who underwent refraction measurements using a portable ARF (Retinomax® K plus 3, Righton, Japan), who did not receive prior cycloplegics under this GA and who had cycloplegic refraction using 1% cyclopentolate and the same Retinomax® device < 3 months prior this GA, between 2015 and 2018, were included in this study. The agreement (Bland-Altman analysis) and correlation (Pearson correlation) between the mean values of the measurements were analyzed. RESULTS Two-hundred-twenty-two right eyes of 222 patients (114 male and 108 female) were included in this study. The mean age was 45.04 ± 11.24 months. The mean spherical refractions (R1-1, R2-1) under GA and cycloplegic refraction were 1.08 ± 3.50 diopter (D) (-8.00 to +8.00) and 2.58 ± 3.28 D (-6.50 to +9.25), respectively. A strong positive correlation was detected between the two measurements (r = 0.95). When comparing measurements, the mean measurement under GA was -1.49 D (95% confidence interval: lower limit, -3.63; upper limit, +0.63) more myopic than the mean cycloplegic refraction (R1-1) value (Bland-Altman analysis test). The differences between the measurements were within ± 1 D in 92 eyes (41.44%) and within ± 2 D in 180 eyes (81.01%). No significant difference was detected when comparing the cylindrical refractive error values (p > .05). CONCLUSION Refractive measurements under GA were more myopic than cycloplegic refraction (R1-1) measurements. It is important to consider that complete cycloplegia is not achieved under GA.
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Affiliation(s)
- Osman Bulut Ocak
- Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul
| | - Asli Inal
- Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul
| | - Beril Tülü Aygün
- Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul
| | - Aslı Kırmacı Kabakci
- Okmeydanı Training and Research Hospital, University of Health Sciences , Istanbul
| | - Burcu Kemer Atik
- Gaziosmanpaşa Taksim Training and Research Hospital, University of Health Sciences , Istanbul
| | - Serap Yurttaser Ocak
- Okmeydanı Training and Research Hospital, University of Health Sciences , Istanbul
| | - Birsen Gökyiğit
- Beyoglu Eye Training and Research Hospital, University of Health Sciences , Istanbul
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Wagner S, Zrenner E, Strasser T. Emmetropes and myopes differ little in their accommodation dynamics but strongly in their ciliary muscle morphology. Vision Res 2019; 163:42-51. [PMID: 31401218 DOI: 10.1016/j.visres.2019.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/23/2019] [Accepted: 08/05/2019] [Indexed: 11/29/2022]
Abstract
Previous work suggested an association between near vision and myopia. We therefore investigated the accommodation process in emmetropes and myopes regarding morphologic changes of the ciliary muscle (CM) and power changes of the lens for different accommodation demands. The temporal CM of 18 emmetropic and 20 myopic students was imaged via anterior segment optical coherence tomography during far and near accommodation (2.5D, 3D, 4D). Additionally, accommodation dynamics to the stimuli pattern far-near-far (15 s each; 2.5D, 3D, 4D) were recorded with eccentric infrared photorefraction. OCT images were processed using custom-developed software facilitating the analysis of selective CM thickness (CMT) readings and CMT profiles. Anterior CMT readings were significantly smaller in myopes. Starting at 1.4 mm posterior to the scleral spur (SP), myopic CM became thicker than emmetropic. Anterior CMT changes (ΔCMT) continuously increased with accommodation demand in myopes while emmetropic ΔCMT only increased from 2.5D to 3D. Compared to emmetropes, myopes showed smaller ΔCMT but increased CM movement relative to SP. There were no significant differences between the groups for accommodation changes from far to near vision and vice versa, velocity, microfluctuations, power spectra or lag of accommodation. At 4 D, larger ΔCMT were associated with lower lens changes for disaccommodation. While CM shape, movement, and thickness showed distinct differences depending on refractive error, emmetropes and myopes did not differ in their dynamic accommodation. Further analysis is necessary to evaluate whether the CM's anatomical shape or predispositions in its intramuscular constituents are causative factors in myopigenesis.
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Affiliation(s)
- Sandra Wagner
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany.
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany; Werner Reichardt Centre for Integrative Neuroscience (CIN) Tuebingen, Otfried-Mueller-Str. 25, 72076 Tuebingen, Germany
| | - Torsten Strasser
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
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Zhang J, Ni Y, Li P, Sun W, Liu M, Guo D, Du C. Anterior Segment Biometry with Phenylephrine and Tropicamide during Accommodation Imaged with Ultralong Scan Depth Optical Coherence Tomography. J Ophthalmol 2019; 2019:6827215. [PMID: 30944731 PMCID: PMC6421770 DOI: 10.1155/2019/6827215] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To investigate the influence of phenylephrine and tropicamide on anterior segment biometry with ultralong scan depth optical coherence tomography (UL-OCT) during accommodation. METHODS In this study, 20 left eyes of healthy volunteers with a mean ± standard deviation age of 31.05 ± 5.84 years and a mean refraction of -1.16 ± 1.11 diopters (range 0∼-3.0 D) were imaged using UL-OCT after instillation of artificial tears, phenylephrine, and tropicamide in three follow-up trials, respectively. At each follow-up trial, two repeated measurements were performed at states of relax and 5D accommodative stimulation. The dimensional parameters included central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter (PD), lens thickness (LT), and horizontal radii of the lens anterior and posterior surface curvatures (LAC and LPC). RESULTS Tropicamide led to larger pupil, deeper ACD, thinner LT, and flatter crystalline lens surface (P < 0.05). Phenylephrine induced an increase in PD (P < 0.05), while no significant changes were seen in ACD, LT, LAC, and LPC (P > 0.05). CCT did not change after both phenylephrine and tropicamide instillation in this study (P > 0.05). Tropicamide induced the loss of accommodation and phenylephrine achieved pupil dilation without affecting the accommodation. PD, ACD decreased, LT increased significantly and the anterior and posterior surface of the lens in a 6.294 mm of diameter optical zone became steeper during accommodation after administration of phenylephrine (P < 0.05). CONCLUSION The anterior segment physiology changed after tropicamide instillation. Besides, tropicamide induced the loss of accommodation and phenylephrine preserved the accommodation with a larger pupil. And, the anterior and posterior surface of lens in a 6.294 mm of diameter optical zone became steeper during the accommodation.
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Affiliation(s)
- Junna Zhang
- Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Yang Ni
- State Key Lab of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Peng Li
- State Key Lab of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Wen Sun
- Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Mengyun Liu
- Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Dongyu Guo
- Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Chixin Du
- Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
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Domínguez-Vicent A, Monsálvez-Romín D, Esteve-Taboada JJ, Montés-Micó R, Ferrer-Blasco T. Effect of age in the ciliary muscle during accommodation: Sectorial analysis. JOURNAL OF OPTOMETRY 2019; 12:14-21. [PMID: 29627301 PMCID: PMC6318550 DOI: 10.1016/j.optom.2018.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 06/02/2023]
Abstract
PURPOSE To compare changes in the ciliary muscle area at different sectors between pre-presbyopic and presbyopic eyes during accommodation by means of an anterior segment optical coherence tomographer (OCT). METHODS The anterior ciliary muscle area was measured in 20 healthy and phakic pre-presbyopic eyes, whose mean age was 23.3±4.4 years, and in 20 healthy and phakic presbyopic eyes, whose mean age was 46.5±5.2 years. The relative change in the cross-sectional area of the ciliary muscle was measured at the nasal, inferior, and temporal sectors between 0 and -3 D of vergence, in -1 D step. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. RESULTS Each population group showed a significant increase in the anterior ciliary muscle area for each sector. The maximum increase in the ciliary muscle area within the pre-presbyopic group was about 30%, and for the presbyopic one was about 25%. At the same time, it was obtained that the larger the vergence, the larger the variability. Furthermore, the linear model showed a positive tendency between the change in the ciliary muscle area of each sector and the vergence for both population groups, which coefficient of determination was in all cases greater than 0.93. CONCLUSION The anterior ciliary muscle area tends to increase with accommodation. The presbyopic nasal, inferior, and temporal ciliary muscle seem to have the same contractile capability as the young presbyopic ciliary muscle. These results might help to increase the evidences in the knowledge regarding the modern understanding of accommodation biometry and biomechanics.
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Affiliation(s)
| | | | - José J Esteve-Taboada
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
| | - Robert Montés-Micó
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
| | - Teresa Ferrer-Blasco
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
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Labhishetty V, Chakraborty A, Bobier WR. Is blur sensitivity altered in children with progressive myopia? Vision Res 2018; 154:142-153. [PMID: 30472331 DOI: 10.1016/j.visres.2018.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 12/25/2022]
Abstract
School aged children with progressive myopia show large accommodative lags to blur only cue which is suggestive of a large depth of focus (DOF). While DOF measures are lacking in this age group, their blur detection and discrimination capacities appear to be similar to their non-myopic peers. Accordingly, the current study quantified DOF and blur detection ability in progressive myopic children showing large accommodative lags compared to their non-myopic peers and adults. Blur sensitivity measures were taken from 12 children (8-13 years, 6 myopes and 6 emmetropes) and 6 adults (20-35 years). DOF was quantified using step changes in the lens induced defocus while the subjects viewed a high contrast target through a Badal lens at either 2 or 4D demand. Blur detection thresholds (BDT) were tested using a similar high contrast target in a 2-alternate forced-choice paradigm (2AFC) at both the demands. In addition to the large accommodative lags, micro fluctuations and DOF were significantly larger in myopic children compared to the other groups. However, BDTs were similar across the three groups. When limited to blur cues, the findings of a large DOF coupled with large response lags suggests that myopes are less sensitive to retinal defocus. However, in agreement to a previous study, refractive error had no influence on their BDTs suggesting that the reduced sensitivity to the defocus in a myopic eye appears to be compensated by some form of an adjustment in the higher visual processes to preserve the subjective percept even with a poor retinal image quality.
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Affiliation(s)
- Vivek Labhishetty
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada.
| | - Arijit Chakraborty
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada
| | - William R Bobier
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada
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Wagner S, Zrenner E, Strasser T. Ciliary muscle thickness profiles derived from optical coherence tomography images. BIOMEDICAL OPTICS EXPRESS 2018; 9:5100-5114. [PMID: 30319924 PMCID: PMC6179398 DOI: 10.1364/boe.9.005100] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 05/09/2023]
Abstract
The purpose of this study was to provide an in-depth analysis of the ciliary muscle's (CM) morphological changes during accommodation by evaluating CM thickness (CMT) profiles. The CM of 15 near-emmetropic subjects (age 20-39) was imaged via optical coherence tomography (OCT) during far (0 D) and near vision (3 D). A custom-made Java-based program was used for semi-automatic CM segmentation and thickness measurements. CMT profiles were generated to determine regions of the largest shape changes. The results revealed on average a thinning within the first 0.25 mm and a thickening from 0.36 to 1.48 mm posterior to scleral spur when accommodating from 0 to 3 D. In contrast to previous analyses, this method offers pixel-wise reconstruction of CM shapes and quantification of accommodative change across the entire muscle boundary.
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Affiliation(s)
- Sandra Wagner
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), Otfried-Mueller-Str. 25, 72076 Tuebingen, Germany
| | - Torsten Strasser
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
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12
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May PJ, Warren S, Gamlin PDR, Billig I. An Anatomic Characterization of the Midbrain Near Response Neurons in the Macaque Monkey. Invest Ophthalmol Vis Sci 2018; 59:1486-1502. [PMID: 29625471 PMCID: PMC5861931 DOI: 10.1167/iovs.17-23737] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose These experiments were designed to reveal the location of the premotor neurons that have previously been designated physiologically as the midbrain near response cells controlling vergence, lens accommodation, and pupillary constriction in response to target distance. Methods To identify this population, the fixed N2c strain of rabies virus was injected into the ciliary body of seven Macaca fascicularis monkeys. The virus was trans-synaptically transported to the brain. Following a 58- to 76-hour survival, animals were perfused with formalin fixative. After frozen sectioning, tissue was reacted to reveal the location of the infected populations by use of a monoclonal anti-rabies antibody. Another series of sections was processed to determine which of the rabies-positive cells were cholinergic motoneurons by use of an antibody to choline acetyl transferase. Results At earlier time points, only cholinergic cells in the preganglionic Edinger-Westphal nucleus ipsilateral to the injection were labeled. At later time points, an additional population of noncholinergic, premotor cells was present. These were most numerous at the caudal end of the supraoculomotor area, where they formed a bilateral band, oriented mediolaterally immediately above the oculomotor nucleus. Rostral to this, a smaller bilateral population was located near the midline within the supraoculomotor area. Conclusions Most lens preganglionic motoneurons are multipolar cells making up a continuous column within the Edinger-Westphal nucleus. A population of premotor cells that likely represents the midbrain near response cells is located in the supraoculomotor area. These cells are bilaterally distributed relative to the eye they control, and are most numerous caudally.
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Affiliation(s)
- Paul J May
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, United States.,Department of Ophthalmology, University of Mississippi Medical Center, Jackson, Mississippi, United States.,Department of Neurology, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Susan Warren
- Department of Neurobiology & Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Paul D R Gamlin
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Isabelle Billig
- Systems Neuroscience Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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Semiautomatic procedure to assess changes in the eye accommodative system. Int Ophthalmol 2017; 38:2451-2462. [PMID: 29075940 DOI: 10.1007/s10792-017-0752-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/16/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE The aim of this pilot study was to evaluate a new semiautomatic procedure to assess in vivo changes in the crystalline lens and ciliary muscle during accommodation. METHODS A total of 14 subjects were divided into two groups, young (aged between 20 and 25 years) and adult (aged between 35 and 40 years), and measured with an anterior segment optical coherence tomography. A semiautomatic procedure was implemented to measure the central lens thickness (CLT), anterior lens radius (ALR) and the ciliary muscle area (CMA) for the unaccommodated eye and for a vergence of - 3.00 D. RESULTS The CLT increase for each population group was smaller than 5%, and the dispersion of each group was similar between them. Contrariwise, the reduction in the ALR was about 30% for both groups, although the young one showed the largest variability. The CMA increase was smaller than 30% for both groups, and the dispersion was similar between them. For each metric, differences between both groups were not statistically significant. CONCLUSIONS The semiautomatic procedure seems to be useful for the in vivo analysis of the accommodative system. Additionally, the results obtained showed that changes in the CLT were much smaller compared to those obtained for the ALR or CMA.
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Abstract
PURPOSE Patients are usually advised to wait 5 minutes between eye drops. This delay supposedly allows the first drop not to be washed out by the second one, thereby increasing the combined effect. However, in the only experimental study conducted in humans on the concurrent administration of two different eye drops, the authors concluded that a 10-minute time interval between eye drops did not increase their combined effect. Our study was designed to address this puzzling observation. METHODS Using digital photographs shot in photopic conditions in 40 eyes of 20 healthy volunteers, we compared relative pupil surface (i.e., pupil to iris surface area ratios) before and after the administration of one drop of 10% phenylephrine and one drop of 0.5% tropicamide either immediately or after a 5-minute time interval. RESULTS Waiting 5 minutes yielded a 5.6% relative pupil surface gain (observer 1: P = .003, observer 2: P = .005) indicating an additional combined effect with a 5-minute time interval. CONCLUSIONS These results show a detectable additive effect that is probably the result of methodological refinements including the challenging of the mydriasis by photopic conditions and the use of pupil and iris surface areas, which may show differences that would be undetectable in terms of diameter.
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Taslimi P, Akıncıoglu H, Gülçin İ. Synephrine and phenylephrine act as α-amylase, α-glycosidase, acetylcholinesterase, butyrylcholinesterase, and carbonic anhydrase enzymes inhibitors. J Biochem Mol Toxicol 2017; 31. [DOI: 10.1002/jbt.21973] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/12/2017] [Accepted: 07/20/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Parham Taslimi
- Department of Chemistry, Faculty of Science; Atatürk University; Erzurum 25240 Turkey
| | - Hülya Akıncıoglu
- Department of Chemistry, Faculty of Science and Arts; Agri Ibrahim Cecen University; Agri 04100 Turkey
| | - İlhami Gülçin
- Department of Chemistry, Faculty of Science; Atatürk University; Erzurum 25240 Turkey
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Effect of Phenylephrine on the Accommodative System. J Ophthalmol 2016; 2016:7968918. [PMID: 28053778 PMCID: PMC5174178 DOI: 10.1155/2016/7968918] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/26/2016] [Indexed: 11/18/2022] Open
Abstract
Accommodation is controlled by the action of the ciliary muscle and mediated primarily by parasympathetic input through postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia. During accommodation the pupil constricts to increase the depth of focus of the eye and improve retinal image quality. Researchers have traditionally faced the challenge of measuring the accommodative properties of the eye through a small pupil and thus have relied on pharmacological agents to dilate the pupil. Achieving pupil dilation (mydriasis) without affecting the accommodative ability of the eye (cycloplegia) could be useful in many clinical and research contexts. Phenylephrine hydrochloride (PHCl) is a sympathomimetic agent that is used clinically to dilate the pupil. Nevertheless, first investigations suggested some loss of functional accommodation in the human eye after PHCl instillation. Subsequent studies, based on different measurement procedures, obtained contradictory conclusions, causing therefore an unexpected controversy that has been spread almost to the present days. This manuscript reviews and summarizes the main research studies that have been performed to analyze the effect of PHCl on the accommodative system and provides clear conclusions that could help clinicians know the real effects of PHCl on the accommodative system of the human eye.
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Ruggeri M, de Freitas C, Williams S, Hernandez VM, Cabot F, Yesilirmak N, Alawa K, Chang YC, Yoo SH, Gregori G, Parel JM, Manns F. Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging. BIOMEDICAL OPTICS EXPRESS 2016; 7:1351-64. [PMID: 27446660 PMCID: PMC4929646 DOI: 10.1364/boe.7.001351] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 05/21/2023]
Abstract
Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence. The image sequences were processed to extract dynamic morphological data from the crystalline lens and the ciliary muscle. The synchronization between the OCT systems allowed the precise correlation of anatomical changes occurring in the crystalline lens and ciliary muscle at identical time points during accommodation. To describe the dynamic interaction between the crystalline lens and ciliary muscle, we introduce accommodation state diagrams that display the relation between anatomical changes occurring in the accommodating crystalline lens and ciliary muscle.
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Affiliation(s)
- Marco Ruggeri
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carolina de Freitas
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Siobhan Williams
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Victor M. Hernandez
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Florence Cabot
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nilufer Yesilirmak
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Karam Alawa
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Yu-Cherng Chang
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
| | - Sonia H. Yoo
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Anne Bates Leach Eye Hospital Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Giovanni Gregori
- Quantitative Imaging Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
- Vision Cooperative Research Centre, Sydney, NSW, Australia
- Brien Holden Vision Institute, Sydney, NSW, Australia
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami, College of Engineering, Coral Gables, FL, USA
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Ramasubramanian V, Glasser A. Objective measurement of accommodative biometric changes using ultrasound biomicroscopy. J Cataract Refract Surg 2015; 41:511-26. [PMID: 25804579 DOI: 10.1016/j.jcrs.2014.08.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 12/01/2022]
Abstract
PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly linearly correlated with accommodative stimulus demands. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD: 0.0176 mm; lens thickness: 0.0294 mm; anterior lens radius of curvature: 0.3350 mm; posterior lens radius of curvature: 0.1580 mm; and anterior segment length: 0.0340 mm). The mean difference between the A-scan and UBM measurements was -0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. FINANCIAL DISCLOSURE Neither author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
| | - Adrian Glasser
- From the College of Optometry, University of Houston, Houston, Texas, USA.
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Koprowski R, Szmigiel M, Kasprzak H, Wróbel Z, Wilczyński S. Quantitative assessment of the impact of blood pulsation on images of the pupil in infrared light. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:1446-1453. [PMID: 26367287 DOI: 10.1364/josaa.32.001446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Pulsation in the blood vessels of the eye has a big impact on the dynamics of the entire eyeball and its individual elements. Blood pulsation in the retina can be recorded by the pupil, whose size is also subject to dynamic changes. The study involved synchronous measurements of pupil size using a high-speed camera, and blood pulsation using a pulse oximeter placed on the ear lobe. In addition, there were no metrologically significant differences in the phase shift between the average brightness of the individual pupil quadrants. Blood pulsation in other ocular tissues can affect the dynamics of the optical properties of the eye. As demonstrated in this paper, it affects the pupil behavior and its parameters to a considerable extent.
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21
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Neri A, Ruggeri M, Protti A, Leaci R, Gandolfi SA, Macaluso C. Dynamic imaging of accommodation by swept-source anterior segment optical coherence tomography. J Cataract Refract Surg 2015; 41:501-10. [PMID: 25704218 DOI: 10.1016/j.jcrs.2014.09.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/05/2014] [Accepted: 09/08/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To study the accommodation process in normal eyes using a commercially available clinical system based on swept-source anterior segment optical coherence tomography (AS-OCT). SETTING Ophthalmology Department, University of Parma, Italy. DESIGN Evaluation of diagnostic technology. METHODS Right eyes were analyzed using swept-source AS-OCT (Casia SS-1000). The optical vergence of the internal coaxial fixation target was adjusted during imaging to obtain monocular accommodation stimuli with different amplitudes (0, 3.0, 6.0, and 9.0 diopters [D]). Overlapping of real and conjugate OCT images enabled imaging of all the anterior segment optical surfaces in a single frame. Central corneal thickness (CCT), anterior chamber depth (ACD), and lens thickness were extracted from the OCT scans acquired at different static accommodation stimulus amplitudes. The crystalline lens was analyzed dynamically during accommodation and disaccommodation by acquiring sequential OCT images of the anterior segment at a rate of 8 frames per second. The lens thickness was extracted from the temporal sequence of OCT images and plotted as a function of time. RESULTS The study analyzed 14 eyes of 14 subjects aged 18 to 46 years. During accommodation, the decrease in the ACD was statistically significant (P < .05), as were the increase in the lens thickness (P < .001) and the slight movement forward of the lens central point (P < .01). The CCT and anterior chamber width measurements did not change statistically significantly during accommodation. The lens thickness at 0 D was positively correlated with age (P < .01). CONCLUSION High-resolution real-time imaging and biometry of the accommodating anterior segment can be effectively performed using a commercially available swept-source AS-OCT clinical device. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Alberto Neri
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
| | - Marco Ruggeri
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Alessandra Protti
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Rosachiara Leaci
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Stefano A Gandolfi
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Claudio Macaluso
- Ophthalmology Department (Neri, Protti, Leaci, Gandolfi, Macaluso), Dipartimento di Scienze Biomediche, Biotecnologiche e Traslazionali, University of Parma, Parma, Italy; the Ophthalmic Biophysics Center (Ruggeri), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
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Effect of pupil dilation on biometry measurements with partial coherence interferometry and its effect on IOL power formula calculation. Eur J Ophthalmol 2015; 25:309-14. [PMID: 25655597 DOI: 10.5301/ejo.5000568] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2015] [Indexed: 12/16/2022]
Abstract
PURPOSE 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. METHODS 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. RESULTS The ACD increased significantly after dilation (+0.12 ± 0.12 mm; p<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). CONCLUSIONS 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.
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Ostrin LA, Garcia MB, Choh V, Wildsoet CF. Pharmacologically stimulated pupil and accommodative changes in Guinea pigs. Invest Ophthalmol Vis Sci 2014; 55:5456-65. [PMID: 25097245 DOI: 10.1167/iovs.14-14096] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The guinea pig is being used increasingly as a model of human myopia. As accommodation may influence the effects of manipulations used in experimental myopia models, understanding the accommodative ability of guinea pigs is important. Here, nonselective muscarinic agonists were used as pharmacological tools to study guinea pig accommodation. METHODS Measurements were made on 15 pigmented guinea pigs. For in vivo testing, animals were anesthetized and, following baseline measurements, 2% pilocarpine was applied topically. Measurements included A-scan ultrasonography, optical coherence tomography (OCT) imaging, corneal topography, and refraction. In vitro lens scanning experiments were performed using anterior segment preparations, with measurements before and during exposure to carbachol. Anterior segment structures were examined histologically and immunohistochemistry was done to characterize the muscarinic receptor subtypes present. RESULTS In vivo, pilocarpine induced a myopic shift in refractive error coupled to a small, but consistent decrease in anterior chamber depth (ACD), a smaller and more variable increase in lens thickness, and a decrease in pupil size. Lens thickness increases were short-lived (10 minutes), while ACD and pupil size decreased over 20 minutes. Corneal curvature was not significantly affected. Carbachol tested on anterior segment preparations in vitro was without effect on lens back vertex distance, but did stimulate pupil constriction. Immunohistochemistry indicated the presence of muscarinic receptor subtypes 1 to 5 in the iris and ciliary body. CONCLUSIONS The observed pilocarpine-induced changes in ACD, lens thickness, and refraction are consistent with active accommodation in the guinea pig, through cholinergic muscarinic stimulation.
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Affiliation(s)
- Lisa A Ostrin
- University of Houston College of Optometry, Houston, Texas, United States
| | - Mariana B Garcia
- University of California Berkeley School of Optometry, Berkeley, California, United States
| | - Vivian Choh
- University of Waterloo Optometry and Vision Science, Waterloo, Ontario, Canada
| | - Christine F Wildsoet
- University of California Berkeley School of Optometry, Berkeley, California, United States
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Shao Y, Tao A, Jiang H, Shen M, Zhong J, Lu F, Wang J. Simultaneous real-time imaging of the ocular anterior segment including the ciliary muscle during accommodation. BIOMEDICAL OPTICS EXPRESS 2013; 4:466-80. [PMID: 23504546 PMCID: PMC3595090 DOI: 10.1364/boe.4.000466] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 05/20/2023]
Abstract
We demonstrated a novel approach of imaging the anterior segment including the ciliary muscle using combined and synchronized two spectral domain optical coherence tomography devices (SD-OCT). In one SD-OCT, a Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera and an alternating reference arm was used to image the anterior segment from the cornea to the lens. Another SD-OCT for imaging the ciliary muscle was equipped with a light source with a center wavelength of 1,310 nm and a bandwidth of 75 nm. Repeated measurements were performed under relaxed and 4.00 D accommodative stimulus states in six eyes from 6 subjects. We also imaged dynamic changes in the anterior segment in one eye during accommodation. The biometry of the anterior segment and the ciliary muscle was obtained. The combined system appeared to be capable to simultaneously real-time image the biometry of the anterior segment, including the ciliary muscle, in vivo during accommodation.
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Affiliation(s)
- Yilei Shao
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, 33136,
USA
- School of Ophthalmology and Optometry, Wenzhou Medical College,
Wenzhou, Zhejiang, China
- These authors contributed equally to this work
| | - Aizhu Tao
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, 33136,
USA
- School of Ophthalmology and Optometry, Wenzhou Medical College,
Wenzhou, Zhejiang, China
- These authors contributed equally to this work
| | - Hong Jiang
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, 33136,
USA
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical College,
Wenzhou, Zhejiang, China
| | - Jianguang Zhong
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, 33136,
USA
- Department of Ophthalmology, Hangzhou First People's Hospital,
Hangzhou, Zhejiang, China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical College,
Wenzhou, Zhejiang, China
| | - Jianhua Wang
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, 33136,
USA
- Electrical and Computer Engineering, University of Miami, Miami, FL,
USA
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Richdale K, Sinnott LT, Bullimore MA, Wassenaar PA, Schmalbrock P, Kao CY, Patz S, Mutti DO, Glasser A, Zadnik K. Quantification of age-related and per diopter accommodative changes of the lens and ciliary muscle in the emmetropic human eye. Invest Ophthalmol Vis Sci 2013; 54:1095-105. [PMID: 23287789 DOI: 10.1167/iovs.12-10619] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To calculate age-related and per diopter (D) accommodative changes in crystalline lens and ciliary muscle dimensions in vivo in a single cohort of emmetropic human adults ages 30 to 50 years. METHODS The right eyes of 26 emmetropic adults were examined using ultrasonography, phakometry, anterior segment optical coherence tomography, and high resolution magnetic resonance imaging. Accommodation was measured both subjectively and objectively. RESULTS In agreement with previous research, older age was linearly correlated with a thicker lens, steeper anterior lens curvature, shallower anterior chamber, and lower lens equivalent refractive index (all P < 0.01). Age was not related to ciliary muscle ring diameter (CMRD) or lens equatorial diameter (LED). With accommodation, lens thickness increased (+0.064 mm/D, P < 0.001), LED decreased (-0.075 mm/D, P < 0.001), CMRD decreased (-0.105 mm/D, P < 0.001), and the ciliary muscle thickened anteriorly (+0.013 to +0.026 mm/D, P < 0.001) and thinned posteriorly (-0.011 to -0.015, P < 0.01). The changes per diopter of accommodation in LED, CMRD, and ciliary muscle thickness were not related to subject age. CONCLUSIONS The per diopter ciliary muscle contraction is age independent, even as total accommodative amplitude declines. Quantifying normal biometric dimensions of the accommodative structures and changes with age and accommodative effort will further the development of new IOLs designed to harness ciliary muscle forces.
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Affiliation(s)
- Kathryn Richdale
- College of Optometry, State University of New York, New York, NY, USA.
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