Coaxial Microscope Research Articles

Front Cover: A frequency mapping method for locating functional units inside ICs based on coaxial microscope

The cover image is based on the Original Article A frequency mapping method for locating functional units inside ICs based on coaxial microscope by Yingqi Ma et al., https://doi.org/10.1049/ell2.12373.

A frequency mapping method for locating functional units inside ICs based on coaxial microscope

Locating the physical position of functional units of the chip is a mandatory first step in various fields of applications, such as reverse engineering and hardware security. This paper presents a frequency mapping method based on the coaxial microscope to locate functional units inside ICs. A visible light camera is employed to focus the laser on the active region of the device under test based on the principle that the laser is strongly reflected at the metal in the active region. The target circuit modulates the laser at its operating frequency and the position of the target circuit could be accurately located by analyzing the frequency characteristics of the reflected laser. The results of transceiver chip localization indicate that the target circuit on the chip can be precisely located by this method without any additional processing of the chip. The coaxial microscopy design provides a good spot quality and signal-to-noise ratio, meanwhile, locating areas of the chip with operating currents down to 10−10 A, compared with that of photonic emission analysis can only achieve the sensitivity of 5 × 10−4 A. The sensitivity of the frequency mapping method is much better than that of Photonic Emission Analysis.

Intraoperative Optical Coherence Tomography: Game-Changing Technology.

Intraoperative optical coherence tomography (OCT) has the potential to revolutionize lamellar corneal surgery and facilitate many other types of ocular surgery because it readily visualizes ocular structures that can be difficult to discern with a coaxial microscope, particularly through a cloudy cornea. Systems that can provide a high-quality image on demand in the surgeon's oculars, rather than just on an adjacent monitor, are the most useful because they allow the surgeon to rely on the OCT image while operating, without having to look away from the surgical field. Useful applications in lamellar corneal surgery include assessing graft attachment with Descemet stripping endothelial keratoplasty and discerning graft orientation with Descemet membrane endothelial keratoplasty, which otherwise could be challenging in an eye with a cloudy cornea. Intraoperative OCT is particularly helpful when performing deep anterior lamellar keratoplasty in cases in which a big bubble should not be attempted or cannot be achieved because it enables better intraoperative control of the incision depth and allows the surgeon to assess the uniformity of the dissection plane to optimize visual outcomes. Intraoperative OCT is also useful when judging the depth of a scar for a lamellar dissection, when evaluating intraocular lens positioning in the capsular bag, or when locating and removing retained nuclear fragments from an eye with a poor view because of a cloudy cornea. The primary barrier to the adoption of this valuable technology is cost.

Customizing Illumination by the Operating Microscope Aids the Visualization of DMEK Grafts

Introduction Our purpose is to present an alternative illumination technique in patients with clouded or opaque corneas, undergoing descemet membrane endothelial keratoplasty (DMEK). Methods Five cases undergoing DMEK surgery with poor visualization of the anterior chamber due to a clouded cornea or corneal opacities were included in the study. Three patients had bullous keratopathy and one patient had a previous corneal transplant failure. All patients underwent DMEK. During graft unfolding and centration, the intensity of the oblique field component of the operating microscope was dimmed by the help of a shutter knob and only coaxial illumination was used to enhance the red reflex. This illumination technique allowed visualization of the graft orientation and succesfull graft positioning was performed in all cases. Results Retroillumination by the coaxial microscope light was especially useful during observation of the correct orientation of the descemet membrane graft during the graft unfolding step of DMEK surgery. Conclusion In cases with more prominent corneal clouding or corneal opacities, retroillumination technique may be helpful in visualization of the anterior chamber and improve outcome of DMEK surgery by preventing the formation of an inverted graft.

Streamlined method for anchoring cataract surgery and intraocular lens centration on the patient's visual axis

I describe an intraoperative method for the consistent anchoring of the intraocular lens (IOL) and cataract surgery and on the patient's visual axis using coaxial microscope optics, surgeon-guided patient fixation, the precision pulse capsulotomy (PPC) device (Zepto) and utilizing the first (and fourth) Purkinje images. During surgery using a microscope with coaxial lights and optics, the patient is instructed to fixate on a given microscope light while the surgeon looks through the corresponding coaxial eyepiece. Then, the PPC device is centered on the Purkinje I image and a capsulotomy is performed. The resulting capsulotomy serves as a reference marker for the visual axis and IOL placement, with even capsule overlap, which results in IOL centration on this axis landmark. This method might help address the high variability in angle κ from patient to patient and provide visual benefits in cases of implantation of multifocal IOLs and other IOLs.

Macular photostress and visual experience between microscope and intracameral illumination during cataract surgery

To evaluate macular photostress and visual experience between coaxial microscope illumination versus oblique intracameral illumination during cataract surgery. Gachon University Gil Hospital, Incheon, South Korea. Prospective case series. Consecutive patients who had cataract surgery using microscope illumination and intracameral illumination were included. The patients were asked to complete a questionnaire (seeing strong lights, feeling photophobia, feeling startled (fright) when seeing lights, seeing any colors, seeing any instruments or surgical procedures, and estimating intraoperative visual function) designed to describe their cataract surgery experience. The images projected on the retina of the model eye (rear view) with artificial opaque fragments in the anterior chamber during simulating cataract surgery were compared between the 2 illumination types. Sixty patients completed the questionnaire. Scores for strong lights, photophobia, fright, and color perception were significantly higher with microscope illumination than with intracameral illumination (all P<.001). More patients preferred the intracameral illumination (45 [75.0%]) to the microscope illumination (13 [21.7%]). In the rear-view images created in a model eye, only the bright microscope light in the center was seen without any lens image in the microscope illumination. However, in the intracameral illumination, the less bright light from the light pipein the periphery and the lens fragments were seen more clearly. In a view of the patients' visual experience, oblique intracameral illumination caused less subjective photostress and was preferred over coaxial microscope illumination. Objective findings from the model-eye experiment correlated to the result of visual experience.

An illuminating retractor for intracranial microneurosurgery.

During certain microneurosurgical procedures, the illumination provided by current coaxial microscope light sources is suboptimal. One potential solution is the surgical light blade (SLB), a malleable retractor incorporating a flat fiberoptic bundle along its surface. The SLB provides intense illumination within the surgical field without decreasing the amount of limited operating space. A prototype of the SLB was tested in six patients. Results suggest that with further development the SLB could become useful for intracranial microneurosurgery.

Decentered ablation zones resulting from photorefractive keratectomy with an erodible mask

Four patients underwent photorefractive keratectomy for compound myopic astigmatism using the erodible mask. All achieved improvements in unaided visual acuities despite manifesting varying levels of decentration of the ablated zones. However, one patient had significant monocular diplopia because of the severity of the decentration. The problems with the present system include the use of a NON coaxial microscope; difficulty with obtaining and maintaining proper alignment of the excimer laser beam to the erodible mask and the central corneal zone; the inability to interrupt and restart the procedure due to the ablation of the reference marks on the mask; and patient discomfort. We suggest installation of the PMMA mask at the laser aperture in order to alleviate the above difficulties. In the meantime, use of a coaxial microscope, a limbal suction device for fixation, permanent reference marks on the mask and peribulbar anaesthesia may be helpful.