Vessel Density Features of Optical Coherence Tomography Angiography for Classification of Optic Neuropathies Using Machine Learning.

BACKGROUND: To evaluate the classification performance of machine learning based on the 4 vessel density features of peripapillary optical coherence tomography angiography (OCT-A) for classifying healthy, nonarteritic anterior ischemic optic neuropathy (NAION), and optic neuritis (ON) eyes. METHODS: Forty-five eyes of 45 NAION patients, 32 eyes of 32 ON patients, and 76 eyes of 76 healthy individuals with optic nerve head OCT-A were included. Four vessel density features of OCT-A images were developed using a threshold-based segmentation method and were integrated in 3 models of machine learning classifiers. Classification performances of support vector machine (SVM), random forest, and Gaussian Naive Bayes (GNB) models were evaluated with the area under the receiver-operating-characteristic curve (AUC) and accuracy. RESULTS: We divided 121 images into a 70% training set and 30% test set. For ON-NAION classification, best results were achieved with 50% threshold, in which 3 classifiers (SVM, RF, and GNB) discriminated ON from NAION with an AUC of 1 and accuracy of 1. For ON-Normal classification, with 100% threshold, SVM and RF classifiers were able to discriminate normal from ON with AUCs of 1 and accuracies of 1. For NAION-normal classification, with 50% threshold, the SVM and RF classified the NAION from normal with AUC and accuracy of 1. CONCLUSIONS: ML based on the combined peripapillary vessel density features of total vessels and capillaries in the whole image and ring image could provide excellent performance for NAION and ON distinction.

In praise of povidone-iodine application in ophthalmology.

Polyvinyl pyrrolidone or povidone-iodine (PVP-I) is a water-soluble complex formed by the combination of iodine and a water-soluble polymer, polyvinyl pyrrolidone. This complex exerts bactericidal, fungicidal, and virucidal action by gradually releasing free iodine at the site of application to react with pathogens. In ophthalmology, PVP-I is used as a disinfectant and antiseptic agent for preoperative preparation of the skin and mucous membranes and for treating contaminated wounds. PVP-I has been shown to reduce effectively the risk of endophthalmitis in various ocular procedures, including cataract surgery and intravitreal injections; however, it has also been used in the treatment of conjunctivitis, keratitis, and endophthalmitis, with promising results especially in low-resource situations. PVP-I has been associated with complications such as postoperative eye pain, persistent corneal epithelial defects, ocular inflammation, and an attendant risk of keratitis. In cases of poor PVP-I tolerance, applying PVP-I at lower concentrations or using alternative antiseptics such as chlorhexidine should be considered. We provide an update on the efficacy of PVP-I in the prophylaxis and treatment of conjunctivitis, keratitis, and endophthalmitis and a comprehensive analysis of the current literature regarding the use of PVP-I in the management of these ocular conditions. Also, PVP-I-related adverse effects and toxicities and its alternatives are discussed. The goal is to present a thorough evaluation of the available evidence and to offer practical recommendations for clinicians regarding the therapeutic usage of PVP-I in ophthalmology.

Vessel Density Features of Optical Coherence Tomography Angiography for Classification of Glaucoma Using Machine Learning.

PRCIS: Machine learning (ML) based on the optical coherence tomography angiography vessel density features with different thresholds using a support vector machine (SVM) model provides excellent performance for glaucoma detection. BACKGROUND: To assess the classification performance of ML based on the 4 vessel density features of peripapillary optical coherence tomography angiography for glaucoma detection. METHODS: Images from 119 eyes of 119 glaucoma patients and 76 eyes of 76 healthy individuals were included. Four vessel density features of optical coherence tomography angiography images were developed using a threshold-based segmentation method and were integrated into 3 models of machine learning classifiers. Images were divided into 70% training set and 30% test set. Classification performances of SVM, random forest, and Gaussian Naive Bayes models were evaluated with the area under the receiver operating characteristic curve (AUC) and accuracy. RESULTS: Glaucoma eyes had lower vessel densities at different thresholds. For differentiating glaucoma eyes, the best results were achieved with 70% and 100% thresholds, in which SVM classifier discriminated glaucoma from healthy eyes with an AUC of 1 and accuracy of 1. After SVM, the random forest classifier with 100% thresholds showed an AUC of 0.993 and an accuracy of 0.994. Furthermore, the AUC of our ML performance (SVM) was 0.96 in a subgroup analysis of mild and moderate glaucoma eyes. CONCLUSIONS: ML based on the combined peripapillary vessel density features of total vessels and capillaries in the whole image and ring image could provide excellent performance for glaucoma detection.

A rare presentation of orbital spindle cell carcinoma a case report and brief review of the literature.

BACKGROUND: To describe a case of orbital spindle cell carcinoma which presented with limbal ischemia and briefly review the literature. METHODS: Retrospective case report and brief literature review. RESULTS: A 61-year old man presented with blepharoptosis, periorbital pain, decreased vision and limbal ischemia. He did not mention any previous illness and did not take any kind of drugs. Imaging revealed an orbital mass that was positive for SMA, Vimentin and CD99 and negative for S100. We treated the patient with chemotherapy and followed him for other complications that occurred throughout disease course. CONCLUSION: Spindle cell carcinomas are a rare variant of squamous cell carcinoma (SCC) with dual malignant histologic differentiation of squamous and mesenchymal cells. Few cases of orbital spindle cell carcinoma have been reported, which have been either secondary to distant metastasis or regional spread. In this study, we have reported the first case of primary orbital spindle cell carcinoma presenting with limbal ischemia. Further studies are needed to describe the different clinical presentations and management strategies of this rare clinical entity.

The effect of povidone-iodine 2% eye drops in the treatment of adenoviral keratoconjunctivitis.

BACKGROUND: Keratoconjunctivitis is one of the most common pathologies worldwide, caused by several infectious and noninfectious factors. This study aimed to determine the effect of povidone-iodine 2% eye drops in treating adenoviral keratoconjunctivitis. METHODS: This analytic cross-sectional study was conducted on patients referred to Farabi Eye Hospital Records of patients with adenoviral keratoconjunctivitis, more than 12 years of age, and no allergy to iodine who were treated by povidone-iodine 2% eye drops four times a day were assessed. Data included demographic characteristics, family history of adenoviral keratoconjunctivitis, follicular conjunctivitis, petechial conjunctival hemorrhages, periauricular lymphadenopathy, and the presence of conjunctival pseudomembrane were collected from the records. Discharge decrease, injection decrease, swelling decrease, pseudomembrane formation, periauricular lymphadenopathy, and subepithelial infiltration on the 7thday of assessment by physical examination were reported. RESULTS: Patients with a mean (±standard deviation) age of 33.77 (11.01) years were assessed. At the baseline, 95 (99.0%) follicular conjunctivitis, 94 (97.9%) petechial conjunctival hemorrhages, 29 (30.2%) periauricular lymphadenopathy, and 5 (5.2%) conjunctival pseudomembrane were recorded. On the 7thday of treatment, the discharge decreased in 92.7% of patients, and the injection decreased in 90.6%. The swelling decrease was also detected in 79.2% of patients. Subepithelial infiltration was only seen in 21.9% of the study population. Results showed that 2.1% of patients had periauricular lymphadenopathy, and only 13 out of 96 patients (13.5%) had pseudomembrane formation after 7 days. CONCLUSIONS: Based on the safety, availability, and tolerability of povidone-iodine and its promising effects on patients with adenoviral keratoconjunctivitis, further clinical trials assessing the impact of this drug in a longer duration of follow-up can be recommended.

Infectious keratitis caused by Klebsiella spp.: predisposing factors, presentation, and management.

PURPOSE: To study predisposing factors, clinical presentation and management strategies for Klebsiella keratitis. METHODS: A retrospective case review was performed on clinical records of culture-proven Klebsiella keratitis cases in a tertiary referral center over an 8-year period (from 2012 to 2020). RESULTS: Thirty eight episodes of culture-proven Klebsiella keratitis were identified in 37 patients. The mean age of the patients was 62.9 years (range, 24-101). Multiple predisposing factors were identified in 33 eyes including history of previous keratoplasty (n = 11) history of ocular trauma (n = 7), preexisting ocular surface disease (n = 7) and diabetes (n = 6). Corrected distance visual acuity (CDVA) at presentation was light perception (LP) in 16 patients, hand motion (HM) in 12, counting fingers (CF) at 50 cm in 5, CF at 1 m in 1, CF at 2 m in 2. One patient had a CDVA of 3/10. On initial examination Hypopyon was detected in 21 eyes. Descemet's membrane folds were present in 1 eye. Corneal thinning was identified in 20 eyes and perforation occurred in 4 patients. Corneal ulcer progressed to endophthalmitis in one patient. Microbiologic sensitivity testing showed that 89.5% isolates were sensitive to amikacin (34/38),88.9%sensitive to ceftazidime (32/36),94.4% were sensitive to gentamicin (34/36),97.2% sensitive to ciprofloxacin (35/36), and 100% to levofloxacin (26/26).Ultimately, one or more surgical procedures was needed in 21 patients. CONCLUSION: Previous keratoplasty, history of ocular trauma, ocular surface disease and systemic disease such as diabetes are major risk factors for Klebsiella keratitis. In most of the patients, surgical and tectonic procedures were necessary to control the infection.

Management of primary choroidal lymphoma presenting as extensive serous retinal detachment and salmon patch of bulbar conjunctiva: a case report.

BACKGROUND: We describe the outcome of ultra-low-dose radiotherapy plus intravitreal methotrexate and rituximab injections for a patient with primary choroidal lymphoma who presented with nodular conjunctival salmon patches and extensive serous retinal detachment. CASE PRESENTATION: A 34-year-old Iranian man presented with a nodular patch of bulbar conjunctiva in the right eye, and 1+ vitritis. A nearly complete shallow serous retinal detachment, retinal folds, and multifocal yellow choroidal infiltrates were seen during a fundus examination of the right eye. Enhanced depth imaging optical coherence tomography revealed macular retinal folds and an uneven, undulating, "seasick" appearance of the choroidal surface with choriocapillaris compression, intraretinal and subretinal fluid, and clusters of optically dense material at the outer retinal level. An incisional biopsy of the conjunctival lesion confirmed the diagnosis of primary choroidal lymphoma with epibulbar involvement. The patient was treated with ultra-low-dose "boom-boom" radiation (4 Gy delivered in two fractions over two consecutive days) as well as intravitreal methotrexate and rituximab injections. After a year, the lesions had completely disappeared, with no adverse effects or recurrence. CONCLUSION: Ultra-low-dose (boom-boom) radiotherapy combined with intravitreal chemotherapy and/or immunotherapy may be an effective treatment for primary choroidal lymphoma with anterior epibulbar extension and diffuse subretinal fluid with favorable response and minimal side effects.