Retinal image enhancement and analysis for diabetic retinopathy assessment
Ahmad Fadzil Mohamad Hani, Dileep Kumar in Optical Imaging for Biomedical and Clinical Applications, 2017
The enhancement of contrast succeeded by RETICA is of great importance to minimize the utilization of invasive operations such as the FFA that has the best emergence of retinal veins. Nevertheless, due to its invasiveness by injecting contrasting agent into the veins, this method can also cause physiological issues such as nausea, spewing and discombobulation [26]. The least favourable case of negative reactions after fluorescein injection may be fatal anaphylactic shock, which can ultimately lead to death [66]. Furthermore, RETICA can be implemented as part of computerised medical diagnosis system to process the image prior to segmenting and analysing the results. The use of RETICA as an image-enhancement method is advantageous to increase sensitivity, specificity and accuracy of the system in diagnosing retina-related eye sicknesses, for example, DR.
Ocular Irritation Testing
David W. Hobson in Dermal and Ocular Toxicology, 2020
As noted above, fluorescein staining is accomplished by placing one or two drops of an ophthalmic solution of sodium fluorescein directly on the cornea, then washing off the excess after a few seconds with isotonic saline. Damaged areas retain more of the dye than the intact epithelium, and appear brighter yellow. Fluorescein is excited maximally by blue light, but fluorescein-stained corneas have been traditionally observed using a long wavelength UV light source, in a darkened room. Since observations are strictly qualitative, controlling the actual wavelength of the light source is not critical. Fluorescein emits light in the yellow-green portion of the spectrum. Damaged areas of the cornea appear bright yellow, and intact portions are a duller green (Plate 3).
Aqueous Humor Dynamics
Neil T. Choplin, Carlo E. Traverso in Atlas of Glaucoma, 2014
Currently, the method of choice to assess aqueous flow is fluorophotometry. Fluorescein is administered to the eye either topically (Figure 3.10) or by corneal iontophoresis. Fluorescein traverses the cornea, enters the anterior chamber, and drains through the chamber angle (Figure 3.11). When equilibrium has been established, the concentrations of fluorescein in the cornea (Cc) and the anterior chamber (Ca) decrease over time. A fluorophotometer (Figure 3.12) is used to monitor these changes. The instrument can focus separately on the cornea and then on the anterior chamber, thus allowing a discrete measurement of each region.
Microvascular neural blood flow assessment for a chronic nerve compression neuropathy mouse model by fluorescein angiography
Published in Neurological Research, 2022
Shunpei Hama, Takuya Yokoi, Mitsuhiro Okada, Takuya Uemura, Kiyohito Takamatsu, Hiroaki Nakamura
FAG was performed using a surgical microscope (Leica M520 MS3, Leica Microsystems, Wetzlar, Germany) and FAG filter (Scimen Design Ltd., Tokyo, Japan) to visualise microvascular blood flow in the compression site of the sciatic nerve for the four groups. The FAG filter, which has three holes corresponding to three holes at the bottom of the surgical microscope cylinder (Figure 2(a)), was made by Ichikawa et al. for FAG [19]. One hole of the FAG filter was covered with an excitatory filter for the microscope light hole allowing the microscope’s light source to pass through, while the other two holes were covered with barrier filters for the two holes used for observing the surgical field. By excluding all wavelengths except for blue light through the FAG filter, light from the microscope to an object becomes blue light. Blue light illuminates and excites the fluorescein in the surgical field. By blocking blue light through the barrier filter, we were able to observe the luminance of fluorescence from the excited fluorescein (Figure 2(b)).
Association of Dry Eye with Laryngopharyngeal Reflux in Clinical Practice
Published in Current Eye Research, 2022
S. Bonini, M. Labetoulle, E. Messmer, P. Aragona, J. M. Benitez Castillo, G. Ciprandi, V. Damiani, M. Irkec, C. Baudouin, M. Rolando
The current study had some limitations, including the retrospective design and the lack of a documented LPR diagnosis. However, RSI is an excellent tool to suspect LPR.49 Moreover, the comparison group included patients with ocular disorders, so they cannot be considered ideal controls, such as healthy subjects. However, the present non-dry eye group included patients with refractive problems, age- and sex-matched, and recruited in everyday practice; thus, the comparison could be legitimate. It has to be highlighted that there was a prevalence of females, it can attribute to a confounding effect, namely dry eye disease is more likely to affect the female sex. In addition, fluorescein BUT was used instead of non-invasive procedures as it is routinely employed in the clinical practice of the participant centers.
Clinical manifestations in anti-Ro52/SS-A antibody-seropositive patients with Sjögren's syndrome
Published in Immunological Medicine, 2021
Hideki Nakamura, Shimpei Morimoto, Toshimasa Shimizu, Ayuko Takatani, Shin-ya Nishihata, Atsushi Kawakami
Our study has some limitations. We did not use the 2016 ACR/EULAR criteria because the ocular staining test, which is one of the main items in the 2016 ACR/EULAR criteria, was not performed in many of our patients. In addition, the use of the Saxon test (one of the stimulated salivary secretion tests used instead of an unstimulated salivary secretion test) might influence the classification of SS. The low execution rate of the fluorescein staining test might also have affected the classification of SS. A fluorescein test is essential for the diagnosis of dry eye. Because this test is required in the 2016 ACR/EULAR criteria as a high-score item, rheumatologists should consult ophthalmologists for the accurate classification of SS. When a sufficient number of enrolled subjects with a complete data set for statistical analyses is obtained, an analysis using the 2016 ACR/EULAR criteria will be necessary.
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