Effects of Image Processing Using Honeycomb-Removal and Image-Sharpening Algorithms on Visibility of 27-Gauge Endoscopic Vitrectomy.

Endoscopic vitrectomy with small gauge probes has clinical potentials, but intraocular visibility is inherently limited by low resolution and dim illumination due to the reduced number of optic fibers. We investigated whether honeycomb-removal and image-sharpening algorithms, which enable real-time processing of live images with a delay of 0.004 s, can improve the visibility of 27-gauge endoscopic vitrectomy. A total of 33 images during endoscopic vitrectomy were prepared, consisting of 11 original images, 11 images after the honeycomb-removal process, and 11 images after both honeycomb-removal and image-sharpening procedures. They were randomly presented to 18 vitreous surgeons, who rated each image on a 10-point scale. The honeycomb-removal algorithm almost completely suppressed honeycomb artifacts without degrading the background image quality. The implementation of image-sharpening algorithms further improved endoscopic visibility by optimizing contrast and augmenting image clarity. The visibility score was significantly improved from 4.27 ± 1.78 for the original images to 4.72 ± 2.00 for the images after the honeycomb-removal process (p < 0.001, linear mixed effects model), and to 5.40 ± 2.10 for the images after both the honeycomb-removal and image-sharpening procedures (p < 0.001). When the visibility scores were analyzed separately for 10 surgeons who were familiar with endoscopic vitrectomy and 8 surgeons who were not, similar results were obtained. Image processing with honeycomb-removal and image-sharpening algorithms significantly improved the visibility of 27-gauge endoscopic vitrectomy.

Improvement in Dacryoendoscopic Visibility after Image Processing Using Comb-Removal and Image-Sharpening Algorithms.

Recently, a minimally invasive treatment for lacrimal passage diseases was developed using dacryoendoscopy. Good visibility of the lacrimal passage is important for examination and treatment. This study aimed to investigate whether image processing can improve the dacryoendoscopic visibility using comb-removal and image-sharpening algorithms. We processed 20 dacryoendoscopic images (original images) using comb-removal and image-sharpening algorithms. Overall, 40 images (20 original and 20 post-processing) were randomly presented to the evaluators, who scored each image on a 10-point scale. The scores of the original and post-processing images were compared statistically. Additionally, in vitro experiments were performed using a test chart to examine whether image processing could improve the dacryoendoscopic visibility in a turbid fluid. The visual score (estimate ± standard error) of the images significantly improved from 3.52 ± 0.26 (original images) to 5.77 ± 0.28 (post-processing images; p < 0.001, linear mixed-effects model). The in vitro experiments revealed that the contrast and resolution of images in the turbid fluid improved after image processing. Image processing with our comb-removal and image-sharpening algorithms improved dacryoendoscopic visibility. The techniques used in this study are applicable for real-time processing and can be easily introduced in clinical practice.

Dacryoendoscopic recanalization of lacrimal passage obstruction/stenosis after radioiodine therapy for differentiated thyroid carcinoma.

PURPOSE: Radioiodine therapy, a standard treatment for differentiated thyroid carcinomas, is associated with several adverse events including lacrimal drainage system obstruction. Herein, we describe the first case of duct lumen recanalization using dacryoendoscopy for lacrimal passage obstruction and stenosis after radioiodine therapy. OBSERVATIONS: A 48-year-old female treated with radioiodine therapy for differentiated thyroid carcinoma 5 years prior presented with epiphora in both eyes. Dacryocystography showed nasolacrimal duct stenosis in the right eye and nasolacrimal duct obstruction in the left eye. Dacryoendoscopic examination revealed right common canalicular polyps, fibrosis in the right lacrimal sac, right nasolacrimal duct stenosis, and left upper and common canaliculus stenosis. Lacrimal passage recanalization with the insertion of a nasolacrimal stent tube using dacryoendoscopy was performed on the right eye. This successfully resolved the epiphora. CONCLUSIONS AND IMPORTANCE: Dacryoendoscopic examination for epiphora after radioiodine therapy may help detect early-stage nasolacrimal passage obstruction/stenosis. This condition can be resolved by recanalization and insertion of a lacrimal tube, without the need for a more invasive surgical approach such as dacryocystorhinostomy.

Assessment of conjunctival flora in eyes with lacrimal passage obstruction before and after successful dacryoendoscopic recanalisation.

BACKGROUND: To investigate conjunctival bacterial flora in eyes with lacrimal passage obstruction before and after dacryoendoscopic recanalisation with lacrimal tube intubation. METHODS: One-hundred fifty eyes with lacrimal passage obstruction that were successfully treated by dacryoendoscopic recanalisation were enrolled. Conjunctival sampling was done for each eye before and 4 months after surgery. The lower fornix was rubbed by a sterile cotton swab, and the collected samples were cultured with several agar plates. Colonies were differentiated and enumerated by standard bacteriological laboratory techniques. RESULTS: Positive bacterial growth was detected in 42.0% of all the samples before surgery, and the positivity rate significantly decreased to 26.0% after surgery (p=0.0051). The number of strains detected also decreased from 20 before surgery to 9 after surgery, especially pathogenic microorganisms decreased. In addition, drug-resistant bacteria such as penicillin-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus were detected in nine eyes before surgery but were detected only in one eye after surgery. Coagulase-negative Staphylococci and Corynebacterium spp., which are common in normal conjunctival flora, accounted for 46.5% of all the isolates before surgery and 80.9% after surgery, showing a significant increase in the rate after surgery (p<0.0001). CONCLUSIONS: This study showed that physiological recanalisation of lacrimal passage after dacryoendoscopic surgery significantly decreased the culture positivity rate of conjunctival sac and the number of microorganism strains detected. It also decreased the number of potentially pathogenic and drug-resistant bacteria and increased the percentages of indigenous bacteria, causing the normalisation of conjunctival flora.

Improvement in Contrast Sensitivity Function after Lacrimal Passage Intubation in Eyes with Epiphora.

This prospective case series aimed to investigate the contrast sensitivity function before and after lacrimal passage intubation (LPI) in eyes with epiphora due to lacrimal passage obstruction. We included 58 eyes of 51 patients who underwent LPI for lacrimal passage obstruction. The best-corrected visual acuity (BCVA), contrast sensitivity function, and lower tear meniscus were compared before LPI and one month after lacrimal duct stent removal. The area under the log contrast sensitivity function (AULCSF) was calculated for the analyses. Lower tear meniscus was assessed using anterior segment optical coherence tomography. The BCVA was comparable (p = 0.61) before and after LPI, while AULCSF increased significantly after treatment (before LPI: 1.29 ± 0.17, after LPI: 1.37 ± 0.14, p < 0.0001). Treatment resulted in a significant increase in contrast sensitivity at all spatial frequencies, 3-18 cycles/degree (p < 0.01 for 3, p < 0.01 for 6, p < 0.0005 for 12, p < 0.05 for 18 cycles/degree). The lower tear meniscus parameters improved significantly after treatment (p < 0.005); however, no correlation between the changes in the tear meniscus and those of the AULCSF was found. The contrast sensitivity significantly improved after LPI in eyes with epiphora due to lacrimal passage obstruction.

Deterioration of contrast sensitivity in eyes with epiphora due to lacrimal passage obstruction.

PURPOSE: Epiphora causes deterioration in contrast sensitivity in some eye diseases. This study was conducted to investigate contrast sensitivity in eyes with epiphora caused by lacrimal passage obstruction. METHODS: This single-center, prospective case series enrolled 57 patients with unilateral lacrimal passage obstruction. The best-corrected visual acuity (BCVA), contrast sensitivity function, and lower tear meniscus of the affected and contralateral unaffected eyes were compared. The area under the log contrast sensitivity function (AULCSF) was calculated. RESULTS: The BCVA did not significantly differ between the affected and contralateral eyes, while the AULCSF was significantly lower in the affected eyes than that in the contralateral eyes (median 1.35, interquartile range 1.22-1.44 vs. median 1.36, interquartile range 1.28-1.46, P = 0.032). Lower tear meniscus parameters were significantly higher in the affected eyes than those in the contralateral eyes (P < 0.005). CONCLUSIONS: The contrast sensitivity function is significantly diminished in eyes with epiphora caused by lacrimal passage obstruction.

Comparison of anterior segment and lens biometric measurements in patients with cataract.

PURPOSE: This study was performed to compare anterior ocular biometric measurements of deep-range swept-source anterior segment optical coherence tomography (AS-OCT) (CASIA2) versus short-range swept-source AS-OCT (CASIA SS-1000), ultrasonography (AL-4000), and Scheimpflug camera analysis (Pentacam and EAS-1000) in patients with cataract. METHODS: One hundred eighty-five eyes of 128 participants with mild refractive error or cataract were examined. The central corneal thickness (CCT), aqueous depth (AQD), and lens thickness were obtained. The repeatability of CASIA2 measurements was assessed. RESULTS: In patients with cataract, the CCT, AQD, lens thickness, and lens anterior curvature by CASIA2 showed high intraclass correlation coefficients (ICCs) of > 0.99. Conversely, measurements of the posterior part of the lens such as lens posterior curvature showed lower ICCs. The ICCs were higher in healthy young participants than in patients with cataract. The ICCs tended to be lower in patients with mild than dense cataract. There was no statistically significant difference in the CCT and AQD between the CASIA2 and CASIA SS-1000 or in the lens thickness measurements between the CASIA2 and AL-4000 and between the CASIA2 and EAS-1000. There was a significant linear correlation in the biometric measurements between the CASIA2 and the other instruments. CONCLUSION: We evaluated the biometric measurements of the anterior eye segment by the CASIA2. The CASIA2 yielded results comparable with those of the CASIA SS-1000, ultrasonography, and Scheimpflug camera. However, mild cataract decreased the repeatability of measurements of the posterior part of the lens.