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Middle East African Journal of... 2014
Topics: Aphakia, Postcataract; Cataract Extraction; Female; Humans; Lens Implantation, Intraocular; Lens Subluxation; Lens, Crystalline; Lenses, Intraocular; Male; Sclera
PubMed: 25371650
DOI: No ID Found -
Advanced Drug Delivery Reviews Feb 2018The suprachoroidal space (SCS) is a potential space between the sclera and choroid that traverses the circumference of the posterior segment of the eye. The SCS is an... (Review)
Review
The suprachoroidal space (SCS) is a potential space between the sclera and choroid that traverses the circumference of the posterior segment of the eye. The SCS is an attractive site for drug delivery because it targets the choroid, retinal pigment epithelium, and retina with high bioavailability, while maintaining low levels elsewhere in the eye. Indeed, phase III clinical trials are investigating the safety and efficacy of SCS drug delivery. Here, we review the anatomy and physiology of the SCS; methods to access the SCS; kinetics of SCS drug delivery; strategies to target within the SCS; current and potential clinical indications; and the safety and efficacy of this approach in preclinical animal studies and clinical trials.
Topics: Administration, Ophthalmic; Animals; Choroid; Drug Delivery Systems; Humans; Kinetics; Sclera
PubMed: 29545195
DOI: 10.1016/j.addr.2018.03.001 -
Ceska a Slovenska Oftalmologie :... 2024To summarize the history and current trends in the use of scleral grafts in ophthalmology. (Review)
Review
AIM
To summarize the history and current trends in the use of scleral grafts in ophthalmology.
MATERIALS AND METHODS
We conducted a review of the literature through the MEDLINE and Cochrane Library databases. The search terms were "sclera", "graft", and "surgery". The search resulted in 1596 articles, of which we evaluated 192 as relevant. The relevant articles were sorted chronologically and according to the method of using scleral grafts, which enabled the development of a review article.
RESULTS
The sclera has been routinely used in ophthalmology since the 1950s in many different indications. Some of these indications have become practically obsolete over time (for example, use in the surgical management of retinal detachment), but a large number still find application today (especially use in glaucoma or oculoplastic surgery, or as a patch for a defect in the sclera or cornea).
CONCLUSION
Even though allogeneic sclera is currently used less frequently in ophthalmology compared to other tissue banking products and the range of its indications has partially narrowed, it remains a useful material due to its availability and properties.
Topics: Humans; Ophthalmology; Sclera; Glaucoma; Retinal Detachment; Cornea
PubMed: 38413226
DOI: 10.31348/2024/11 -
BMC Ophthalmology Jan 2021However there have been numerous investigations of intrascleral intraocular lens (IOL) fixation techniques, there is room for improvement in terms of simplifying...
BACKGROUNDS
However there have been numerous investigations of intrascleral intraocular lens (IOL) fixation techniques, there is room for improvement in terms of simplifying complicated techniques and reducing the high levels of skill required. This study aimed to report a novel technique for sutureless intrascleral fixation of the IOL using retinal forceps with a 27-gauge trocar.
METHODS
Nineteen eyes of 18 patients underwent intrascleral fixation of the IOL from July 2018 to September 2019 were enrolled in this study. A 27-gauge trocar formed 3-mm scleral tunnels positioned at 4 and 10 o'clock, 2 mm from the corneal limbus. We used a 3-piece IOL haptic grasped by a 27-gauge retinal forceps and pulled from the 27-gauge trocar. The IOL was fixed by making a flange. Main outcome measures were visual acuity, corneal endothelial cell density, IOL tilt, decentration, predicted error of refraction and complications.
RESULTS
The 19 eyes were followed up for 1 month. The mean pre- and postoperative logMAR uncorrected visual acuity (UCVA) was 1.06 ± 0.63 and 0.40 ± 0.26, respectively (p < 0.01), while the mean pre- and postoperative logMAR best corrected visual acuity (BCVA) was 0.27 ± 0.51 and 0.06 ± 0.15, respectively (p = 0.09). The mean corneal endothelial cell density was 2406 ± 625 to 2004 ± 759 cells/mm at 1 month (p = 0.13). The mean IOL tilt was 3.52 ± 3.00°, and the mean IOL decentration was 0.39 ± 0.39 mm. There was no correlation among IOL tilt, decentration and BCVA (p > 0.05). The mean prediction error of the target refraction was - 0.03 ± 0.93 D. The complications were vitreous hemorrhage (3 eyes), hyphema (1 eye), IOP elevation (1 eye), iris capture of the IOL (1 eye) and hypotony (2 eyes). No IOL dislocation occurred.
CONCLUSIONS
IOL intrascleral fixation with a flange achieved good IOL fixation and visual outcome in the scleral tunnels created with the 27-gauge trocar.
Topics: Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Retrospective Studies; Sclera; Surgical Instruments; Suture Techniques
PubMed: 33407262
DOI: 10.1186/s12886-020-01758-6 -
Experimental Eye Research May 2017Aqueous humor flows out of the eye primarily through the conventional outflow pathway that includes the trabecular meshwork and Schlemm's canal. However, a fraction of... (Review)
Review
Aqueous humor flows out of the eye primarily through the conventional outflow pathway that includes the trabecular meshwork and Schlemm's canal. However, a fraction of aqueous humor passes through an alternative or 'unconventional' route that includes the ciliary muscle, supraciliary and suprachoroidal spaces. From there, unconventional outflow may drain through two pathways: a uveoscleral pathway where aqueous drains across the sclera to be resorbed by orbital vessels, and a uveovortex pathway where aqueous humor enters the choroid to drain through the vortex veins. We review the anatomy, physiology and pharmacology of these pathways. We also discuss methods to determine unconventional outflow rate, including direct techniques that use radioactive or fluorescent tracers recovered from tissues in the unconventional pathway and indirect methods that estimate unconventional outflow based on total outflow over a range of pressures. Indirect methods are subject to a number of assumptions and generally give poor agreement with tracer measurements. We review the variety of animal models that have been used to study conventional and unconventional outflow. The mouse appears to be a promising model because it captures several aspects of conventional and unconventional outflow dynamics common to humans, although questions remain regarding the magnitude of unconventional outflow in mice. Finally, we review future directions. There is a clear need to develop improved methods for measuring unconventional outflow in both animals and humans.
Topics: Animals; Aqueous Humor; Humans; Intraocular Pressure; Limbus Corneae; Models, Animal; Sclera; Secretory Pathway; Trabecular Meshwork; Uvea
PubMed: 26850315
DOI: 10.1016/j.exer.2016.01.017 -
Progress in Molecular Biology and... 2015In the regulation of ocular growth, scleral events critically determine eye size and thus the refractive status of the eye. Increased scleral matrix remodeling can lead... (Review)
Review
In the regulation of ocular growth, scleral events critically determine eye size and thus the refractive status of the eye. Increased scleral matrix remodeling can lead to exaggerated eye growth causing myopia and additionally increased risk of ocular pathological complications. Thus, therapies targeting these changes in sclera hold potential to limit such complications since sclera represents a relatively safe and accessible drug target. Understanding the scleral molecular mechanisms underlying ocular growth is essential to identifying plausible therapeutic targets in the sclera. This section provides a brief update on molecular studies that pertain to the sclera in the context of ocular growth regulation and myopia.
Topics: Biomechanical Phenomena; Humans; Models, Biological; Myopia; Sclera
PubMed: 26310158
DOI: 10.1016/bs.pmbts.2015.05.005 -
Clinical & Experimental Optometry May 2019Anterior segment optical coherence tomography (OCT) provides a wealth of opportunities for modern contact lens practice. OCT imaging has numerous clinical and research... (Review)
Review
Anterior segment optical coherence tomography (OCT) provides a wealth of opportunities for modern contact lens practice. OCT imaging has numerous clinical and research applications related to the tear film, cornea, conjunctiva, sclera and ocular adnexae, in addition to soft, rigid, and hybrid contact lenses. This review summarises the potential use of OCT imaging in modern scleral contact lens practice including initial lens selection, assessing the scleral contact lens fit with respect to the cornea and sclera, and accurately quantifying the ocular response to lens wear. Recent advances in the understanding of anterior segment metrics including scleral thickness, curvature, toricity, and the anatomy of the corneoscleral limbal junction are also discussed.
Topics: Contact Lenses; Corneal Topography; Humans; Prosthesis Fitting; Sclera; Tomography, Optical Coherence
PubMed: 30062745
DOI: 10.1111/cxo.12814 -
Acta Ophthalmologica Mar 2019To characterize the mean topographical shape of the human sclera of a normal eye.
PURPOSE
To characterize the mean topographical shape of the human sclera of a normal eye.
METHODS
Forty-five participants aged from 19 to 45 years and with no previous ocular surgeries were included in this study. Four three-dimensional (3D) corneo-scleral maps from both eyes were acquired using a corneo-scleral topographer (Eye Surface Profiler). For each 3D map, the sclera (maximum diameter of 16 mm) and cornea were automatically separated at the level of the limbus. The remaining 3D scleral ring was further fit to a quadratic function. The elevation difference between the original and fit data was calculated. For statistical analysis, sclera was divided into eight sectors: nasal, temporal, superior, inferior, supero-nasal, supero-temporal, inferior-nasal and inferior-temporal. In addition, sclera was separated as inner sclera (inner ring of 6-7-mm radius) and outer sclera (external ring of 7-8-mm radius).
RESULTS
Horizontally, the nasal area of the sclera showed less elevation [mean (SD) -30 (52) μm (OD)] than the temporal area [mean (SD) 4 (47) μm (OD)], p < 0.001. Vertically, the inferior area of the sclera [mean (SD) 32 (72) μm (OD)] was slightly less elevated than the superior area (mean (SD) 36 (84) μm, but this difference was not statistically significant (p = 0.40). Besides, the asymmetry of the sclera was found to increase with radial distance from the corneal apex. No statistically significant difference was found between right and left eye.
CONCLUSION
Human sclera is rotationally asymmetric, and its shape varies considerably between subjects.
Topics: Adult; Cornea; Corneal Topography; Female; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Reference Values; Sclera; Tomography, Optical Coherence; Young Adult
PubMed: 30146759
DOI: 10.1111/aos.13901 -
Clinical & Experimental Optometry Nov 2020Myopia, and especially high myopia, is associated with a number of posterior segment changes that are considered to be mostly a consequence of the increased axial... (Review)
Review
Myopia, and especially high myopia, is associated with a number of posterior segment changes that are considered to be mostly a consequence of the increased axial elongation. This can result in mechanical strain, attendant vascular changes, stretching and thinning of tissues, and atrophy/deformation of tissues in later or more advanced stages. Such myopia-related changes are observed as changes and/or abnormalities in the vitreous, choroid, retina and peripheral retina, sclera and/or optic disc. Although many of these changes are benign, at times they may be associated with significant vision impairment that either requires active intervention or may suggest future progression of the disease. This review systematically addresses the posterior segment conditions seen in myopic eyes, describes the features associated with the condition and details management pathways.
Topics: Choroid; Humans; Myopia; Optic Disk; Retina; Sclera
PubMed: 32227385
DOI: 10.1111/cxo.13060 -
Journal of Healthcare Engineering 2018The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis.... (Review)
Review
INTRODUCTION
The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis. The presented definition and measurement method allow for the analysis of image sequences of eye responses-cornea deformation. In particular, the outer corneal contour and sclera fragments are analysed, and 3D reconstruction is performed.
METHODS
On this basis, well-known parameters such as eyeball reaction or corneal response are determined. The next steps of analysis allow for automatic and reproducible separation of four different corneal vibrations. These vibrations are associated with (1) the location of the maximum of cornea deformation; (2) the cutoff area measured in relation to the cornea in a steady state; (3) the maximum of peaks occurring between applanations; and (4) the other characteristic points of the corneal contour.
RESULTS
The results obtained enable (1) automatic determination of the amplitude of vibrations; (2) determination of the frequency of vibrations; and (3) determination of the correlation between the selected types of vibrations.
CONCLUSIONS
These are diagnostic features that can be directly applied clinically for new and archived data.
Topics: Algorithms; Biomechanical Phenomena; Cornea; Data Collection; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Intraocular Pressure; Sclera; Tonometry, Ocular; Vibration; Video Recording
PubMed: 29610655
DOI: 10.1155/2018/5705749