Abstract: Anthropometry can analyze the size, weight, and proportion of the human body objectively and quantitatively to supplement the visual assessment. Various non-invasive three-dimensional (3D) anthropometric techniques have been applied to assess soft tissues’ 3D morphology in the clinical practice. Among them, non-invasive stereophotogrammetry and laser scanning techniques are becoming increasingly popular in craniofacial surgery and plastic surgery. They have been applied for craniofacial growth estimation and morphometric investigation, genetic and acquired malformation diagnosis, as well as orthodontic or surgical treatment arrangement and outcome evaluation. However, few studies have been published for assessing the 3D morphology of soft tissues in the periorbital region. This paper reviews the studies involving the application and evaluation of the increasingly popular 3D photogrammetry in the periorbital region. These studies proposed detailed and standardized protocols for three-dimensionally assessing linear, curvilinear, angular, as well as volumetric measurements, and verified its high reliability in the periorbital region (even higher than caliper-derived direct measurements). In the future, reliable and accurate 3D imaging techniques, as well as standardized analyzing protocols, may find applications in following up morphological growth, preoperatively diagnosing and assessing patient periorbital conditions, planning surgical procedures, postoperatively evaluating treatment outcomes of a specific procedure, and comparing the differences in surgical results between various procedures, studies, as well as populations.
Abstract: Glaucoma is a group of eye diseases that seriously threaten human visual health. Increased intraocular pressure is the main clinical manifestation and diagnostic basis of glaucoma and is directly related to increased resistance to aqueous circulation channels. The trabecular meshwork (TM) is a multi-layer spongy tissue that filters aqueous humor. Its structure changes and the filtering capacity decreases, leading to an increase in intraocular pressure. Surgical methods for TM are constantly updated. Compared with traditional glaucoma surgical techniques, such as external trabeculectomy, the development of a new surgical technique—minimally invasive glaucoma surgery (MIGS)—enables the operation to reduce intraocular pressure efficiently while further reducing damage to the eye. MIGS achieves the purpose of surgery mainly by optimizing the TM outflow pathway, uveoscleral outflow pathway, and subconjunctival outflow pathway. A new surgical instrument, the Kahook Dual Blade, appears to optimize the TM outflow pathway in the surgical technique. The Kahook Dual Blade is a new type of angle incision instrument. Because of its unique double-edged design, in the process of goniotomy, it can effectively reduce the damage to the anterior chamber angle structure and accurately remove the appropriate amount of TM so that the aqueous humor can flow out smoothly. Kahook Dual Blade goniotomy has the advantages of avoiding complications and foreign body sensation caused by intraocular implants. The operation time is relatively short, the surgical technique is easy to master, and the TM resection scope can be determined based on the patient’s condition. It can be used to treat some clinically meaningful glaucoma. This article is organized as follows. We present the following article following the Narrative Review reporting checklist.
Abstract: Navigation technology in ophthalmology, colloquially called “eye-tracking”, has been applied to various areas of eye care. This approach encompasses motion-based navigation technology in both ophthalmic imaging and treatment. For instance, modern imaging instruments use a real-time eye-tracking system, which helps to reduce motion artefacts and increase signal-to-noise ratio in imaging acquisition such as optical coherence tomography (OCT), microperimetry, and fluorescence and color imaging. Navigation in ophthalmic surgery has been firstly applied in laser vision corrective surgery and spread to involve navigated retinal photocoagulation, and positioning guidance of intraocular lenses (IOL) during cataract surgery. It has emerged as one of the most reliable representatives of technology as it continues to transform surgical interventions into safer, more standardized, and more predictable procedures with better outcomes. Eye-tracking is essential in refractive surgery with excimer laser ablation. Using this technology for cataract surgery in patients with high preoperative astigmatism has produced better therapeutic outcomes. Navigated retinal laser has proven to be safer and more accurate compared to the use of conventional slit lamp lasers. Eye-tracking has also been used in imaging diagnostics, where it is essential for proper alignment of captured zones of interest and accurate follow-up imaging. This technology is not routinely discussed in the ophthalmic literature even though it has been truly impactful in our clinical practice and represents a small revolution in ophthalmology.
Background: Cells of the retinal pigment epithelium (RPE) accumulate different kinds of granules (lipofuscin, melanolipofuscin, melanosomes) within their cell bodies, with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation. High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration (AMD); however, this has not been confirmed in histology so far. Here, based on our previous dataset of RPE granule characteristics, we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence (AF) intensities.
Methods: RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy (HR-SIM) and laser scanning microscopy (LSM). Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules. In addition, total AF intensity per cell and granule density (number of granules per cell area) were determined. For the final analysis, RPE cells with total granule number below 5th or above the 95th percentile, or a total AF intensity ± 1.5 standard deviations above or below the mean were included, and compared to the average RPE cell at the same location. Data are presented as mean ± standard deviation.
Results: Within 420 RPE cells examined, 42 cells were further analyzed due to extremes regarding total granule numbers. In addition, 20 RPE cells had AF 1.5 standard deviations below, 28 RPE cells above the mean local AF intensity. Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity. RPE cells with high granule content have nearly twice (1.8 times) as many granules as an average RPE cell.
Conclusions: In normal eyes, outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells, suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level. The AF of a cell is related to the composition of intracellular granule types. Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscin′s role in aging and AMD further into perspective.
Backgrounds: To assess changes in anterior segment biometry during accommodation using a swept source anterior segment optical coherence tomography (SS-OCT). Methods: One hundred-forty participants were consecutively recruited in the current study. Each participant underwent SS-OCT scanning at 0 and -3 diopter (D) accommodative stress after refractive compensation, and ocular parameters including anterior chamber depth (ACD), anterior and posterior lens curvature, lens thickness (LT) and lens diameter were recorded. Anterior segment length (ASL) was defined as ACD plus LT. Lens central point (LCP) was defined as ACD plus half of the LT. The accommodative response was calculated as changes in total optical power during accommodation. Results: Compared to non-accommodative status, ACD (2.952±0.402 vs. 2.904±0.382 mm, P<0.001), anterior (10.771±1.801 vs. 10.086±1.571 mm, P<0.001) and posterior lens curvature (5.894±0.435 vs. 5.767±0.420 mm, P<0.001), lens diameter (9.829±0.338 vs. 9.695±0.358 mm, P<0.001) and LCP (4.925±0.274 vs. 4.900±0.259 mm, P=0.010) tended to decreased and LT thickened (9.829±0.338 vs. 9.695±0.358 mm, P<0.001), while ASL (6.903±0.279 vs. 6.898±0.268 mm, P=0.568) did not change significantly during accommodation. Younger age (β=0.029, 95% CI: 0.020 to 0.038, P<0.001) and larger anterior lens curvature (β=-0.071, 95% CI: -0.138 to -0.003, P=0.040) were associated with accommodation induced greater steeping amplitude of anterior lens curvature. The optical eye power at 0 and -3 D accommodative stress was 62.486±2.284 and 63.274±2.290 D, respectively (P<0.001). Age was an independent factor of accommodative response (β=-0.027, 95% CI: -0.038 to -0.016, P<0.001). Conclusions: During -3 D accommodative stress, the anterior and posterior lens curvature steepened, followed by thickened LT, fronted LCP and shallowed ACD. The accommodative response of -3 D stimulus is age-dependent.
Objective: In this review, non-transgenic models of age-related macular degeneration (AMD) are discussed, with focuses on murine retinal degeneration induced by sodium iodate and lipid peroxide (HpODE) as preclinical study platforms.
Background: AMD is the most common cause of vision loss in a world with an increasingly aging population. The major phenotypes of early and intermediate AMD are increased drusen and autofluorescence, Müller glia activation, infiltrated subretinal microglia and inward moving retinal pigment epithelium (RPE) cells. Intermediate AMD may progress to advanced AMD, characterized by geography atrophy and/or choroidal neovascularization (CNV). Various transgenic and non-transgenic animal models related to retinal degeneration have been generated to investigate AMD pathogenesis and pathobiology, and have been widely used as potential therapeutic evaluation platforms.
Methods: Two retinal degeneration murine models induced by sodium iodate and HpODE are described. Distinct pathological features and procedures of these two models are compared. In addition, practical protocol and material preparation and assessment methods are elaborated.
Conclusions: Retina degeneration induced by sodium iodate and HpODE in mouse eye resembles many clinical aspects of human AMD and complimentary to the existent other animal models. However, standardization of procedure and assessment protocols is needed for preclinical studies. Further studies of HpODE on different routes, doses and species will be valuable for the future extensive use. Despite many merits of murine studies, differences between murine and human should be always considered.
Background: Axonal degeneration caused by damage to the optic nerve can result in a gradual death of retinal ganglion cells (RGC), leading to irreversible vision loss. An example of such diseases in humans includes optic nerve degeneration in glaucoma. Glaucoma is characterized by the progressive degeneration of the optic nerve and the loss of RGCs that can lead to loss of vision. The different animal models developed to mimic glaucomatous neurodegeneration, all result in RGC loss consequent optic nerve damage.
Methods: The present article summarizes experimental procedures and analytical methodologies related to one experimental model of glaucoma induced by optic nerve crush (ONC). Point-by-point protocol is reported with a particular focus on the critical point for the realization of the model. Moreover, information on the electroretinogram procedure and the immunohistochemical detection of RGCs are described to evaluate the morpho-functional consequences of ONC.
Discussion: Although the model of ONC is improperly assimilated to glaucoma, then the ONC model simulates most of the signaling responses consequent to RGC apoptosis as observed in models of experimental glaucoma. In this respect, the ONC model may be essential to elucidate the cellular and molecular mechanisms of glaucomatous diseases and may help to develop novel neuroprotective therapies.
