Recognition of Glaucomatous Fundus Images Using Machine Learning Methods Based on Optic Nerve Head Topographic Features.

PURPOSE: The aim was to compare the effectiveness of clinical discriminant rules and machine learning classifiers in identifying glaucomatous fundus images based on optic disc topographic features. DESIGN: Retrospective case-control study. METHODS: The study used a total of 800 fundus images, half of which were glaucomatous cases and the other half non- glaucomatous cases obtained from an open database and clinical work. The images were randomly divided into training and testing sets with equal numbers of glaucomatous and non-glaucomatous images. An ophthalmologist framed the edge of the optic cup and disc, and the program calculated five features, including the vertical cup-to-disc ratio and the width of the optic rim in four quadrants in pixels, used to create machine learning classifiers. The discriminative ability of these classifiers was compared with clinical discriminant rules. RESULTS: The machine learning classifiers outperformed clinical discriminant rules, with the extreme gradient boosting method showing the best performance in identifying glaucomatous fundus images. Decision tree analysis revealed that the cup-to-disc ratio was the most important feature for identifying glaucoma fundus images. At the same time, the temporal width of the optic rim was the least important feature. CONCLUSIONS: Machine learning classifiers are an effective approach to detecting glaucomatous fundus images based on optic disc topographic features and integration with an automated program for framing and calculating the required parameters would make it a straightforward and effective approach.

An eye tracking study of the application of gestalt theory in photography.

Photography is an art form where integration of the human visual perception and psychological experiences result in aesthetic pleasure. This research utilizes eye tracking to explore the impact of the properties of Gestalt in photography on people's visual cognitive process in order to understand the psychological processes and patterns of photography appreciation. This study found that images with Gestalt qualities can significantly affect fixation, sightline distribution, and subjective evaluation of aesthetics and complexity. Closure composition images seem to make cognition simpler, resulting in the least number of fixation and saccades, longer fixation duration, and more concentrated sightline indicating stronger feeling of beauty, while images which portray similarity results in the greatest fixation and saccades, longest saccade duration, and greater scattering of sightline, indicating feelings of complexity and unsightliness. The results of this research are closely related to the theories of art and design, and have reference value for photography theory and application.

Spontaneous Closure of Cyclodialysis Cleft in a Case of Normal-Tension Glaucoma Post Ab-Interno Trabeculotomy.

A cyclodialysis cleft (CDC) is the detachment of longitudinal ciliary muscle from scleral spur, causing an unusual communication between anterior chamber and suprachoroidal space, resulting in possible hypotony. We report a case of a 63-year-old woman with normal-tension glaucoma (NTG), who developed a shallow anterior chamber with relatively low intraocular pressure (IOP, 6-8 mmHg) after combined ab-interno trabeculotomy and phacoemulsification. Her vision reached good (20/20) with the mild myopic shift. After detecting subtle signs of clinical hypotony, CDC was confirmed and monitored using anterior segment optical coherence tomography. Five months after surgery, she encountered an episode of eye pain, with transient IOP elevation and deepening of the anterior chamber. Spontaneous closure of CDC was suspected and confirmed gonioscopically. To the best of our knowledge, this is the first case to describe the clinical course of spontaneous CDC closure in a patient with NTG after ab-interno trabeculotomy. It is advisable to inform the patient about potential IOP spike after spontaneous closure once CDC is diagnosed.

A refractory malignant glaucoma posttrabeculectomy in vitrectomized eye: A case report and review of the literature.

The objective of this study is to report a case of refractory malignant glaucoma post trabeculectomy in vitrectomized eye and review of previous literature in PubMed database. A 63-year-old male encountered malignant glaucoma after trabeculectomy in vitrectomized eye. We had tried vitreous tapping with peripheral iridectomy and vitreous tapping with intracameral injection of room air (Chandler procedure). All of previous procedures were in vain. Finally, the yttrium-aluminum-garnet laser membranectomy with zonulectomy was done. The intraocular pressure is within normal range without any topical glaucoma eye drops during 3-year outpatient department regular follow-up. Complete vitrectomy with a patent tunnel from posterior chamber to anterior chamber (iridectomy-zonulectomy) is the effective procedure to manage of malignant-like glaucoma.

Descemet's membrane detachment following uneventful phacoemulsification surgeries: A case report.

RATIONALE: Descemet's membrane detachment (DMD) may occur during or following cataract surgery, causing corneal edema and visual loss1. The incidence of DMD after phacoemulsification surgery is only approximately 0.5%, and mostly surgical-related. Late onset bilateral spontaneous DMD after sequential uneventful cataract surgeries, is even rarer, and may result from not only surgery itself, but also from an underlying anatomic abnormality 2. PATIENT CONCERNS: We present a 80 year old female developed bilateral descemet's membrane detachment after sequential uncomplicated cataract surgeries. DIAGNOSIS: Bilateral Descemet's membrane detachment. INTERVENTIONS: One eye (left eye) was treated with intracameral air injection and the fellow eye (right eye) was treated with medical treatment only. OUTCOMES: The DMDs were reattached in both eyes after treatment. Surgical intervention accelerated the duration of recovery and there were no significant outcome differences between the right and the left eye. LESSONS: Even if there is a large area of DMD with visual axis involvement, conservative treatment with close observation might still provide a satisfactory result if Descemet's membrane is separated from the posterior corneal stroma by ≤1 mm.

Glaucomatocyclitic Crises May Occur in Patients with Narrow or Closed Angles.

PURPOSE: To report cases of glaucomatocyclitic crises and discuss the possibility of occurrence in patients with narrow or closed angles. BACKGROUND: The prevalence of angle closure is much higher among Asians than among the Western population. Currently, there is no evidence for a direct relationship between the etiology and angle structure. DESIGN: A retrospective and observational case series. METHODS: We retrospectively collected data from nine adult patients (three males and six females) who were diagnosed with a glaucomatocyclitic crisis and a shallow anterior chamber over a 21-year period, from 1995 to 2016, at the Kaohsiung Medical University Hospital. A narrow angle was defined as a grade less than the Shaffer system grade II. Ophthalmic examinations, including anterior segment biomicroscopy, direct ophthalmoscopy, intraocular pressure measurements, anterior chamber reaction, visual field tests, and the grade of the anterior chamber angle according to the Shaffer system, were reviewed. RESULTS: These patients experienced at least one typical unilateral ocular hypertensive episode that fulfilled the criteria of a glaucomatocyclitic crisis without the angle feature. All patients had gonioscopically narrow or closed angles with or without peripheral anterior synechiae. CONCLUSIONS: The coexistence of narrow or closed angles and a glaucomatocyclitic crisis is possible, especially in patients of Asian descent. In patients with shallow anterior chambers, a glaucomatocyclitic crisis may be a cause of acute glaucoma episodes.

Management of hypotony after glaucoma filtering surgery.

A 39-year-old male with open angle glaucoma in both eyes visited our clinic. The intraocular pressure (IOP) of both eyes fluctuated between 15 mmHg and 25 mmHg. The best corrected visual acuity (BCVA) was 20/20 in the right eye and 20/100 in the left eye. He underwent trabeculectomy with an adjunctive agent (mitomycin C; concentration, 0.2 mg/mL) smoothly on the right eye. After the removal of releasable sutures, the filtering bleb was prominent over the superior limbus for 3 consecutive clock hours with an IOP of about 4-5 mmHg. The Seidel test result was negative, and the anterior chamber depth was moderate to deep. The BCVA of the right eye decreased to 20/100, and optical coherence tomography revealed macular edema. We injected sodium hyaluronate (Healon, Abbott Medical Optics, Santa Ana, CA, USA) into the anterior chamber 2 months after the operation, and repeated the same procedure 4 days later. After each injection, the IOP spiked up to 50 mmHg, and an intravenous infusion of mannitol was required. Sodium hyaluronate was found migrating into the bleb on post-injection day 1. Then we decided to revise the bleb by suturing the scleral flap at two sides. The IOP of the right eye returned to 10 mmHg 4 days after the revision surgery. The BCVA of the right eye recovered to 20/20 6 months after the revision. Optical coherence tomography also showed recovery from macular edema. One IOP-lowering agent (1% brinzolamide ophthalmic suspension) was required for IOP control after bleb revision. Early revision of the scleral flap may resolve hypotony and associated serious complications.

Uncorrected visual acuity and noncycloplegic autorefraction predict significant refractive errors in Taiwanese preschool children.

PURPOSE: To investigate the accuracy of uncorrected visual acuity (UCVA), stereopsis, and noncycloplegic autorefraction (NCAR) tests performed by vision-screening technicians and to determine the best referral criteria when using these methods to screen for significant refractive errors in preschool children. DESIGN: Retrospective, case-control, and cross-sectional study. PARTICIPANTS: We reviewed 1000 records for a population-based preschool vision-screening program. The target conditions were defined as myopia ≤-3.0 diopters (D), hyperopia ≥ 4.5 D, astigmatism ≥ 2.0 D, and anisometropia ≥ 2.0 D. METHODS: Receiver operating characteristic (ROC) curve was used to calculate optimal referral cutoff values. The examination results obtained by the vision-screening technicians were compared with those obtained by a pediatric ophthalmologist, which were considered the gold standard. MAIN OUTCOME MEASURES: The efficacies (sensitivity, specificity, positive predictive value, and negative predictive value) of different tests were evaluated. RESULTS: In 7.0% (95% confidence interval [CI], 5.3-8.7) of the children, at least 1 eye showed 1 of the target conditions. If only the right eyes were considered, the prevalence of target conditions was 4.2% (95% CI, 2.9-5.5). The ROC curve analysis indicated that the NCAR cylinder test (cutoff value ≥ 0.875 D) was the best test for screening target conditions. With regard to age groups, UCVA ≤ 0.75 (Snellen equivalent) and ≤ 0.85 were the best referral criteria for ages ≤ 4 years and ≥ 5 years, respectively. Combining the UCVA test with the NCAR test (the child was referred after failing both tests) increased specificity without significantly decreasing sensitivity. CONCLUSIONS: The UCVA and NCAR tests performed by vision-screening technicians are adequately sensitive and specific for preschool vision screening. The ROC curve analysis was used for determining the appropriate screening criteria for these tests, and combining the tests increased their accuracy. The screening criteria should be age dependent. When analyzing the test accuracy in ophthalmic problems, if the disease of interest does not symmetrically (in terms of disease severity and prevalence) involve both eyes, the prevalence based on only 1 eye should be interpreted with caution.

Comparison of vitrectomy alone and combined vitrectomy, phacoemulsification and intraocular lens implantation for proliferative diabetic retinopathy.

There have been concerns that there may be an increased incidence of iris neovascularization (NV) following lens removal in patients with proliferative diabetic retinopathy (PDR). In this study, we retrospectively compared vitrectomy alone and vitrectomy combined with phacoemulsification (phacovitrectomy) and intraocular lens implantation regarding both complications and results. Fifty-three eyes for vitrectomy group and 31 eyes for phacovitrectomy group were included. Postoperative iris and angle NV were found in eight (15.1%) eyes in the first group and no (0%) eyes in the second. The incidence was significantly lower (p < 0.05) in the phacovitrectomy group. The final vision gain of one or more lines was found in 17 (32.1%) and 21 (67.7%) eyes, respectively. There was significantly better vision improvement in the phacovitrectomy group. We consider the combined procedure to be useful as an alternative surgical treatment for patients with PDR and cataract formation.

Culture of retinal pigment epithelium from evisceration specimens.

Human retinal pigment epithelial (RPE) cell cultures are usually obtained from donor eyes; isolation and culture of RPE cells obtained by evisceration has not been reported previously. The present study attempted to isolate and cultivate RPE cells from evisceration specimens obtained from two cases with severe ocular trauma. Two different isolation methods, explantation and enzymatic dissociation, were used. In Case 1, RPE cells grew from the explants, but were contaminated with other cells such as fibroblasts and melanocytes, and no pure RPE cultures were obtained by explantation. In Case 2, RPE cells were separated from choroids using 0.25% trypsin before plating for culture, which effectively eliminated contaminating cells. A pure RPE culture was obtained and cultured with F12 medium supplemented with 30% fetal bovine serum. With this enzymatic dissociation method, cultured RPE cells grew to confluence in primary culture and could be maintained in culture for five passages. Cultured RPE cells were identified by the presence of cytokeratin expression, as shown by immunocytochemical staining. These isolation and culture methods provide alternative sources for human RPE cells and could be useful in studies of the cell biology and pathophysiology of human RPE cells.

Suture fixation technique for posterior chamber intraocular lenses.

We describe a modified method for scleral fixation of posterior chamber intraocular lenses (IOLs). A double-armed, 10-0 polypropylene (Prolene) suture on a curved long needle is passed through a groove in the sclera and retrieved within the barrel of a bent 25-gauge needle through the opposite groove. Double transscleral passages enable 4-point fixation and provide better stability and centration. Knots are buried completely in the scleral groove. In a series of 10 cases, the IOLs were well centered, no sutures protruded from the scleral groove, and the vision in all eyes improved. In 1 case, a ciliary hemorrhage occurred during insertion of the 25-gauge needle, but the bleeding stopped after ocular pressure reform. This technique is easy to perform, improves centration and stability of the IOL, and avoids suture exposure.

The cell cycle distribution of cultured human retinal pigmented epithelial cells under exposure of anti-proliferative drugs.

It has been well documented that RPE cells play an important role in the formation of proliferative vitreoretinopathy (PVR). We studied the effects of four most widely used anti-proliferative drugs, i.e., 5-fluorouracil (5-FU), daunomycin (DM), mitomycin C (MMC) and dexamethasone (DEX) in an in vitro model system (cultured human RPE). The cells treated with indicated concentrations of drugs for 48 h were harvested for DNA content analysis. In addition, a time course study with constant dosage of drugs was performed. The results revealed that, after incubation for 48 h, an increased percentage (31.1%) of S phase cells was noted with exposure to MMC (10 ng/ml). It was confirmed by 5-bromodeoxyuridine (BrdU) incorporation test that this increase does not result from higher transition rate from G1 to S phase. The cells of G2/M phase markedly increased from 13.8% to 29.7% with 10 ng/ml DM. We also demonstrated that 5-FU and MMC treatment led to cell accumulation at S phase and DM treatment resulted in cell accumulation at G2/M phase, These findings were compatible with their pharmacological mechanisms. Development of an in vitro model using cultured human RPE to study the effects of various anti-proliferative drugs on cell cycle can provide a rapid, safe and inexpensive method for selection of drugs used for management of PVR.