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Indian Journal of Ophthalmology Dec 2020Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates... (Review)
Review
Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.
Topics: Anterior Chamber; Humans; Iris; Lens Implantation, Intraocular; Lenses, Intraocular; Myopia; Phakic Intraocular Lenses
PubMed: 33229653
DOI: 10.4103/ijo.IJO_2995_20 -
Clinical & Experimental Optometry Mar 2017Trabeculectomy is the most common surgical procedure for the management of glaucoma, which may significantly influence ocular biometry. Axial length and anterior chamber... (Review)
Review
Trabeculectomy is the most common surgical procedure for the management of glaucoma, which may significantly influence ocular biometry. Axial length and anterior chamber depth tend to decrease, while crystalline lens and choroidal thickness increase post-operatively. An increase in with-the-rule astigmatism is also observed after the procedure. Such biometric changes affect intraocular lens power calculation even years after the procedure. Non-contact biometric methods and postponing cataract surgery after trabeculectomy could reduce calculation errors associated with surgically induced alterations in ocular biometrics.
Topics: Anterior Chamber; Axial Length, Eye; Biometry; Cataract Extraction; Choroid; Cornea; Humans; Lens, Crystalline; Trabeculectomy
PubMed: 27686794
DOI: 10.1111/cxo.12477 -
BMC Ophthalmology Feb 2022A simple technique to facilitate removal of subincisional cortex in cataract surgery is presented.
BACKGROUND
A simple technique to facilitate removal of subincisional cortex in cataract surgery is presented.
METHODS
A disposable 27-gauge blunt needle attached to a 5.0-ml syringe containing balanced salt solution (BSS) is introduced through the side port incision into the anterior chamber. The tip of the needle is directed toward the capsule fornix beneath the incision site, and BSS is flushed to disperse the remaining cortex. Thereafter, the coaxial irrigation/aspiration device is used to remove the loosened cortex.
RESULTS
This technique was used in 60 eyes of 60 patients with difficulty of removing cortical remnant in the subincisional space. Subincisional cortical material was successfully removed in 93.3% (56/60 eyes). There were no intraoperative and postoperative complications related to this procedure.
CONCLUSIONS
The hydro-dispersion technique is a simple and safe approach to remove the subincisional cortical material that is difficult to manage with the standard coaxial irrigation/aspiration device.
Topics: Anterior Chamber; Cataract Extraction; Humans; Lens, Crystalline; Phacoemulsification; Postoperative Complications; Therapeutic Irrigation
PubMed: 35177028
DOI: 10.1186/s12886-022-02314-0 -
Eye (London, England) Jan 2020Differentiating the two main forms of primary glaucoma (open-angle and closed-angle glaucoma) depends on the correct assessment of the anterior chamber angle (ACA). This... (Review)
Review
Differentiating the two main forms of primary glaucoma (open-angle and closed-angle glaucoma) depends on the correct assessment of the anterior chamber angle (ACA). This assessment will determine the management plan and prognosis for the disease. The standard method of examining the angle has been, for many years, slit-lamp gonioscopy. This method, although clinically still useful, is less robust for patient follow up and clinical research, given its low reproducibility. Several imaging technologies have been developed in recent years to improve the evaluation of the ACA and overcome the shortcomings of gonioscopy. These recent advances include three-dimensional and 360° analysis by Swept-Source OCT (SS-OCT, CASIA, Tomey, Nagoya, Japan), the introduction of deep learning algorithms for automatic imaging classification and new goniophotographic systems. SS-OCT allows for the first time the assessment of the circumferential extension of angle closure with moderate to good diagnostic performance compared with gonioscopy. Deep learning algorithms are showing promising results for the automation of imaging analysis, and may potentially save physicians' time in regards of the interpretation of the images. Lastly, goniophotograph systems have the distinct advantage of recordability of gonioscopic findings and are most closely matched to the findings of slit-lamp gonioscopy.
Topics: Anterior Chamber; Anterior Eye Segment; Glaucoma, Angle-Closure; Gonioscopy; Humans; Intraocular Pressure; Japan; Prospective Studies; Reproducibility of Results; Tomography, Optical Coherence
PubMed: 31666710
DOI: 10.1038/s41433-019-0655-0 -
Clinical & Experimental Optometry Jan 2021Proper selection of phakic intraocular lens diameter is necessary to avoid complications related with excessive vaulting after its implantation.
CLINICAL RELEVANCE
Proper selection of phakic intraocular lens diameter is necessary to avoid complications related with excessive vaulting after its implantation.
BACKGROUND
Horizontal corneal diameter, measured as white-to-white distance, is one of the parameters used for phakic intraocular lens diameter calculation. Agreement was assessed between three parameters: white-to-white distance obtained with swept source optical coherence tomography, and white-to-white distance obtained with Scheimpflug camera and angle-to-angle parameter obtained with anterior segment optical coherence tomography.
METHODS
This study included 55 eyes of 43 patients. The white-to-white distance was measured with two biometry techniques: swept source optical coherence tomography and Scheimpflug camera. The angle-to-angle was measured with anterior segment optical coherence tomography. Analysis of agreement was performed by the Bland-Altman method. For every patient, simulation of Visian Implantable Collamer Lens (ICL) sizing was performed using the Online Calculation and Ordering System with different white-to-white distance or angle-to-angle.
RESULTS
Statistically significant differences were found between swept source optical coherence tomography biometer and anterior segment optical coherence tomography (p = 0.001) and between swept source optical coherence tomography and Scheimpflug camera (p < 0.001). However, there was a good correlation between swept source optical coherence tomography and Scheimpflug camera (intraclass correlation co-efficient = 0.623), with a shift toward higher white-to-white distance values on swept source optical coherence tomography. A relatively high correlation intraclass correlation co-efficient (0.772) and lack of statistically significant differences (p = 0.068) between anterior segment optical coherence tomography and Scheimpflug camera results were observed. Simulation of phakic intraocular lens sizing showed that swept source optical coherence tomography white-to-white distance should not be used interchangeably with Scheimpflug camera white-to-white distance or angle-to-angle.
CONCLUSION
White-to-white distance measured with swept source optical coherence tomography was significantly different from values obtained with other methods. Angle-to-angle may support ICL sizing, helping in verification of white-to-white distance values obtained with other devices.
Topics: Anterior Chamber; Biometry; Humans; Phakic Intraocular Lenses; Tomography, Optical Coherence
PubMed: 32519362
DOI: 10.1111/cxo.13101 -
Physiological Reviews Jul 2024The anterior chamber of the eye (ACE) is distinct in its anatomy, optics, and immunology. This guarantees that the eye perceives visual information in the context of... (Review)
Review
The anterior chamber of the eye (ACE) is distinct in its anatomy, optics, and immunology. This guarantees that the eye perceives visual information in the context of physiology even when encountering adverse incidents like inflammation. In addition, this endows the ACE with the special nursery bed iris enriched in vasculatures and nerves. The ACE constitutes a confined space enclosing an oxygen/nutrient-rich, immune-privileged, and less stressful milieu as well as an optically transparent medium. Therefore, aside from visual perception, the ACE unexpectedly serves as an excellent transplantation site for different body parts and a unique platform for noninvasive, longitudinal, and intravital microimaging of different grafts. On the basis of these merits, the ACE technology has evolved from the prototypical through the conventional to the advanced version. Studies using this technology as a versatile biomedical research platform have led to a diverse range of basic knowledge and in-depth understanding of a variety of cells, tissues, and organs as well as artificial biomaterials, pharmaceuticals, and abiotic substances. Remarkably, the technology turns in vivo dynamic imaging of the morphological characteristics, organotypic features, developmental fates, and specific functions of intracameral grafts into reality under physiological and pathological conditions. Here we review the anatomical, optical, and immunological bases as well as technical details of the ACE technology. Moreover, we discuss major achievements obtained and potential prospective avenues for this technology.
Topics: Humans; Prospective Studies; Anterior Chamber
PubMed: 38206586
DOI: 10.1152/physrev.00024.2023 -
Arquivos Brasileiros de Oftalmologia 2021To evaluate the corneal and anterior chamber morphology in phakic eyes with noninfectious intraocular inflammation.
PURPOSE
To evaluate the corneal and anterior chamber morphology in phakic eyes with noninfectious intraocular inflammation.
METHODS
This study included 59 eyes with active uveitis, 62 with inactive uveitis, and 95 healthy eyes. Corneal endothelial cell density, hexagonal cell ratio, coefficient of variation (CV), corneal thickness and volume, maximum keratometry, and anterior chamber volume and depth (ACD) measurements were performed using a specular microscope and Pentacam HR.
RESULTS
The mean duration of uveitis was 24.6 ± 40.5 (0-180) months. The mean number of uveitis attacks was 2.8 ± 3.0 (1-20). Coefficient of variation was significantly higher in the active uveitis group compared with inactive uveitis group (p=0.017, Post Hoc Tukey). Anterior segment parameters other than coefficient of variation were not significantly different between active/inactive uveitis and control groups (p>0.05). Multiple linear regression analysis showed that coefficient of variation was greater in active uveitis compared with inactive uveitis after adjusting for the duration of uveitis, type of uveitis, having a rheumatologic disease, and having immunosuppressive treatment (p=0.003). The duration of uveitis and number of attacks were not significantly correlated with ocular parameters (p>0.05, Spearman's correlation). The difference in parameters was not significant based on uveitis type (p>0.05).
CONCLUSIONS
Coefficient of variation was higher in eyes with active uveitis than that in eyes with inactive uveitis, whereas corneal endothelial cell density and anterior chamber morphology did not significantly differ between active/inactive uveitis and control groups.
Topics: Anterior Chamber; Cornea; Humans; Inflammation; Microscopy; Uveitis
PubMed: 33567019
DOI: 10.5935/0004-2749.20210030 -
Pharmacology & Therapeutics May 2019Diabetes develops due to deficient functional β cell mass, insulin resistance, or both. Yet, various challenges in understanding the mechanisms underlying diabetes... (Review)
Review
Diabetes develops due to deficient functional β cell mass, insulin resistance, or both. Yet, various challenges in understanding the mechanisms underlying diabetes development in vivo remain to be overcome owing to the lack of appropriate intravital imaging technologies. To meet these challenges, we have exploited the anterior chamber of the eye (ACE) as a novel imaging site to understand diabetes basics and clinics in vivo. We have developed a technology platform transplanting pancreatic islets into the ACE where they later on can be imaged non-invasively for long time. It turns out that the ACE serves as an optimal imaging site and provides implanted islets with an oxygen-rich milieu and an immune-privileged niche where they undergo optimal engraftment, rich vascularization and dense innervation, preserve organotypic features and live with satisfactory viability and functionality. The ACE technology has led to a series of significant observations. It enables in vivo microscopy of islet cytoarchitecture, function and viability in the physiological context and intravital imaging of a variety of pathological events such as autoimmune insulitis, defects in β cell function and mass and insulin resistance during diabetes development in a real-time manner. Furthermore, application of the ACE technology in humanized mice and non-human primates verifies translational and clinical values of the technology. In this article, we describe the ACE technology in detail, review accumulated knowledge gained by means of the ACE technology and delineate prospective avenues for the ACE technology.
Topics: Animals; Anterior Chamber; Biomedical Research; Diabetes Mellitus; Humans; Islets of Langerhans Transplantation
PubMed: 30677477
DOI: 10.1016/j.pharmthera.2019.01.005 -
Translational Vision Science &... May 2021To establish anterior chamber measurements in children and investigate the influence of demographic factors on anterior chamber development.
PURPOSE
To establish anterior chamber measurements in children and investigate the influence of demographic factors on anterior chamber development.
METHODS
Handheld optical coherence tomography was used to scan the anterior chamber of participants' eyes, without sedation. ImageJ was used to generate quantitative anterior chamber measurements, including central corneal thickness (CCT), anterior chamber width, trabecular meshwork length (TML), Schwalbe's line-angle opening distance (SL-AOD), and trabecular iris surface area (SL-TISA). The average anterior chamber measurements per age group, with 95% prediction intervals, were estimated using fractional polynomial modeling. Mixed regression models were used to evaluate the influence of age, gender, eye, angle, and refractive error variation on anterior chamber measurements.
RESULTS
Scans from 223 healthy children (2 days to 15 years of age) and 59 adults (16 to 47 years of age) were included. The anterior chamber width, TML, Schwalbe's line-angle opening distance, and Schwalbe's line-trabecular iris surface area significantly increased, whereas CCT decreased with aging (all P < 0.001). The anterior chamber has a rapid phase of development during the first 18 months of age and reaches maturity by the age of 5 years. Girls have significantly smaller anterior chambers compared with boys (all P < 0.001). There was no difference between right and left eye development (all P > 0.05). The temporal TML development was significantly greater than the nasal TML (P < 0.05). CCT development was negatively correlated with refractive power.
CONCLUSIONS
This novel, non-invasive study describes the postnatal development of anterior chamber in newborn children.
TRANSLATIONAL RELEVANCE
Our established quantitative measurements have potential clinical use in understanding anterior segment diseases.
Topics: Adult; Anterior Chamber; Child, Preschool; Cross-Sectional Studies; Female; Humans; Infant, Newborn; Iris; Male; Middle Aged; Tomography, Optical Coherence; Trabecular Meshwork
PubMed: 34111257
DOI: 10.1167/tvst.10.6.13 -
Eye (London, England) Jun 2022To describe anterior chamber angle (ACA) structures and parameters in primary congenital glaucoma (PCG) and normal infant eyes, using Hand-held anterior segment optical...
PURPOSE
To describe anterior chamber angle (ACA) structures and parameters in primary congenital glaucoma (PCG) and normal infant eyes, using Hand-held anterior segment optical coherence tomography (HH AS-OCT), as an in-office, non-contact technique.
METHODS
Normal and PCG-infants <24 months were examined, using HH AS-OCT (RTVue RT- 100, Optovue Inc., Fremont, CA). Sedation was not required. Corneal pachymetry map, ACA width and iris thickness (IT) were measured. Trabecular meshwork (TM), Schlemm's canal (SC), and scleral spur (SS) identification were assessed in both groups.
RESULTS
Forty-eight infants; (26 PCG-eyes and 22 normal-eyes) aged 9.12 ± 6.7 months, were included. Nasal and temporal ACA width in PCG infants was found significantly larger (39.3 ± 6.6° vs. 30.4 ± 5.6, and 40.1 ± 5.3° vs. 32.5 ± 6.2 respectively) (p < 0.001). IT was significantly reduced (121.7 ± 43.9 μm in PCG-infants, vs. 160.3 ± 38.6 μm in normal-eyes) (p < 0.01). TM was identified in all normal eyes (100%) and nine (34.6%) PCG- eyes. SC was identified in 16 (72.7%) normal eyes versus four (15.4%) PCG. In PCG-eyes, an abnormal structure occluding the angle was seen in seven (26.9%), and a hyper-reflective membrane in five (19.2%), the iris was anteriorly inserted in all PCG-eyes, and iridotrabeculodysgenesis was clearly identified (with constant iris anterior insertion). The abnormal tissue obscuring the angle was seen in younger PCG-infants and iris thinning appeared to be part of the pathology, not a result of IOP elevation.
CONCLUSION
Using HH AS-OCT permits tomographic examination of the ACA in PCG infants and may help in the understanding of disease pathology. Hence, may assist in optimizing treatment.
Topics: Anterior Chamber; Glaucoma; Glaucoma, Angle-Closure; Humans; Infant; Intraocular Pressure; Iris; Tomography, Optical Coherence; Trabecular Meshwork
PubMed: 34117386
DOI: 10.1038/s41433-021-01583-1