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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 -
Indian Journal of Ophthalmology May 2023The most common cause of corneal graft failure is corneal graft rejection (CGR). Although cornea is one of the immune-privileged sites, it can still get a rejection... (Review)
Review
The most common cause of corneal graft failure is corneal graft rejection (CGR). Although cornea is one of the immune-privileged sites, it can still get a rejection episode due to a breach in its natural protective mechanism. Both anatomical and structural properties of cornea and anterior chamber contribute toward its immune tolerance. Clinically, every layer of the transplanted cornea can get a rejection episode. A proper understanding of immunopathogenesis will help in understanding the various mechanism of CGR and the development of newer strategies for the prevention and management of such cases.
Topics: Humans; Corneal Transplantation; Graft Rejection; Corneal Diseases; Cornea; Anterior Chamber; Postoperative Complications; Keratoplasty, Penetrating
PubMed: 37203024
DOI: 10.4103/IJO.IJO_2866_22 -
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 -
Current Opinion in Ophthalmology Jul 2022To review the current literature on Descemet membrane endothelial keratoplasty (DMEK) in complex eyes. (Review)
Review
PURPOSE OF REVIEW
To review the current literature on Descemet membrane endothelial keratoplasty (DMEK) in complex eyes.
RECENT FINDINGS
DMEK surgery has become a standardized procedure in Fuchs endothelial dystrophy and simple bullous keratopathy. But eyes with more complex disease present unique intraoperative and postoperative challenges to the DMEK surgeon. Poor visualization during surgery, complex anterior segment anatomy, altered anterior chamber dynamics, glaucoma shunts, and congenital or iatrogenic missing or altered iris and lens make DMEK surgery extremely difficult to accomplish.
SUMMARY
DMEK is feasible in complex eyes, including advanced bullous keratopathy, eyes with history of glaucoma or vitreoretinal surgery, previous penetrating keratoplasty, uveitis, pediatric, and congenital anterior segment disorders. The tools and methods reported in the literature to accomplish DMEK in complex eyes vary widely with no particular consensus or standardization of techniques. The outcomes noted for some of these conditions demonstrate the difficulty of the surgery and the uncertainty of long-term graft survival in complex eyes. Both surgical standardization and randomized prospective data will better help elucidate DMEK's role in the corneal rehabilitation of complex eyes.
Topics: Child; Descemet Membrane; Descemet Stripping Endothelial Keratoplasty; Endothelium, Corneal; Glaucoma; Humans; Prospective Studies; Visual Acuity
PubMed: 35779057
DOI: 10.1097/ICU.0000000000000865 -
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 -
Acta Ophthalmologica Jun 2022In a healthy eye, the aqueous humour (AH) flows via the ciliary body and trabecular meshwork into the collector channels, which carry it to the episcleral veins. In... (Review)
Review
In a healthy eye, the aqueous humour (AH) flows via the ciliary body and trabecular meshwork into the collector channels, which carry it to the episcleral veins. In glaucoma, a heterogeneous group of eye disorders affecting approximately 60 million individuals worldwide, the juxtacanalicular meshwork offers greater resistance to the outflow of the AH, leading to an increase in outflow resistance that gradually results in elevated intraocular pressure (IOP). The present review comprehensively covers the morphology of Schlemm's canal (SC) and AH pathways. The path of the AH from the anterior chamber through the trabeculum into suprascleral and conjunctival veins via collector channels is described, and the role of SC in the development of glaucoma and outflow resistance is discussed. Finally, channelography is presented as a precise method of assessing the conventional drainage pathway and facilitating localization of an uncollapsed collector and aqueous veins. Attention is also given to the relationship between aqueous and episcleral veins and heartbeat. Possible directions of future research are proposed.
Topics: Aqueous Humor; Glaucoma; Humans; Intraocular Pressure; Sclera; Trabecular Meshwork
PubMed: 34519170
DOI: 10.1111/aos.15027 -
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 -
Der Ophthalmologe : Zeitschrift Der... Jul 2021We report a Patient with Fuchs dystrophy who underwent three Descemet Membrane Endothelial Keratoplasties (DMEK) caused by recurrent graft failure with raise in...
We report a Patient with Fuchs dystrophy who underwent three Descemet Membrane Endothelial Keratoplasties (DMEK) caused by recurrent graft failure with raise in intraocular pressure and cystoid macular edema. At the third DMEK, herpes was detected in the anterior chamber tap and an adequate therapy was initiated. At the 6 months follow-up the cornea remained clear, visual acuity was 0.8, intraocular pressure was within normal range and macular edema regressed completely. Either a latent Herpes simplex Virus (HSV) infection of the patient was reactivated or an infected donor lamella was transplanted with donor-to-host-to-donor ping-pong transmission.
Topics: Cornea; Descemet Membrane; Descemet Stripping Endothelial Keratoplasty; Endothelium, Corneal; Fuchs' Endothelial Dystrophy; Humans; Retrospective Studies; Visual Acuity
PubMed: 32728805
DOI: 10.1007/s00347-020-01184-5