Artificial intelligence in glaucoma detection using color fundus photographs.

PURPOSE: To explore the potential of artificial intelligence (AI) for glaucoma detection using deep learning algorithm and evaluate its accuracy for image classification of glaucomatous optic neuropathy (GON) from color fundus photographs. METHODS: A total of 1375 color fundus photographs, 735 normal optic nerve head and 640 GON, were uploaded on the AI software for training, validation, and testing using deep learning model, which is based on Residual Network (Res Net) 50V2. For initial training and validation, 400 fundus images (200 normal and 200 GON) were uploaded and for the final training and testing 975 (535 normal and 440 GON) were uploaded later. Accuracy, sensitivity, and specificity were used to evaluate the image classification performance of the algorithm. Also, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated. RESULTS: The model used in the study showed an image classification accuracy of 81.3%, sensitivity of 83%, and specificity of 80% for the detection of GON. The false-negative grading was 17% and false-positive grading was 20% for the image classification of GON. Coexistence of glaucoma in patients with high myopia, early glaucoma in a small disc, and software misclassification of GON were the reasons for false-negative results. Physiological large cupping in a large disc, myopic or titled disc, and software misclassification of normal optic disc were the reasons for false-positive results. CONCLUSION: The model employed in this study achieved a good accuracy, and hence has a good potential in detection of GON using color fundus photographs.

High false-positive response in perimetry.

Background: In Humphrey visual field analyzer, the false-positive (FP) responses imply that the patient has pressed the response button despite no stimulus being seen at the time of response and FP rates >15% are flagged. The classical "Trigger happy" visual field has increased fixation loss, very high threshold retinal sensitivity with the values in supernormal range, "white scotoma" on grayscale map, high positive mean deviation (MD), glaucoma hemifield test (GHT) gives classification of "abnormally high sensitivity, 'Excessive high false positive' message is displayed," and pattern deviation probability plot has more defects than total deviation probability plot known as "reverse cataract pattern." However, these classical findings are not seen in all the cases of FP as the same thumb rule cannot be applied to all the visual fields with high FP. Purpose: This video emphasizes the significance of careful examination of all the parameters in a visual field printout of high FP to interpret the test results and the caution needed when an FP response is seen in a patient with advanced glaucoma. Synopsis: The video presents some interesting visual fields in normal and glaucoma patients and the effect of high FP responses on MD, the different classification messages displayed for GHT, patterns of total deviation probability plot and pattern deviation probability plot, and how to identify the hidden FP. Highlights: This video highlights the importance of careful examination of all the parameters in a visual field printout to interpret the test results. One should be especially cautious when an FP response is noted in a patient with advanced glaucoma, as the retinal sensitivity values may not be in supernormal range but are significantly affected by the increased FP. Clinician should be able to identify this and repeat the test as high FP reponses can lead to underestimation of visual field loss. Video link: https://youtu.be/T2SGZf16UzA.

Long and short of Ahmed glaucoma valve tube.

Background: The Ahmed Glaucoma Valve (AGV, New World Medical Inc., Rancho Cucamonga, CA, USA) is a glaucoma drainage device commonly used in the treatment of refractory glaucoma either as a primary surgical procedure or after the failure of conventional filtration procedures. During surgery, After the AGV plate is fixed to the sclera, at least 8 mm posterior to the corneoscleral limbus, the length of tube is trimmed to the desired length, based on decision to insert it in the anterior chamber (AC) or ciliary sulcus. Purpose: This video describes that the length of AGV silicone tube should be cut based on decision to place it in the AC or ciliary sulcus. The tube should not be cut too long or short as in either case it may cause postoperative complications. Synopsis: The video illustrates useful tips for AGV tube insertion into the AC, taking care that it does not cross pupillary margin and is of adequate length. The silicone AGV tube is cut using Westcott scissors to permit a length of 2- to 3-mm tube insertion in the AC, with its bevel facing up, and the tip is cut to an angle of 30°, to facilitate AC entering. In ciliary sulcus placement of the AGV tube, the tunnel is made longer when compared with the AC implantation, and the length of tube should be kept long enough for the tip to be just visible beyond the pupillary border. Highlights: This video highlights the importance of customization of the AGV tube length for individual patients based on its placement into AC or ciliary sulcus. Video link: https://youtu.be/jqS4SvCkSqs.

Bilateral interface fluid syndrome and glaucoma progression after laser-assisted in situ keratomileusis.

A 32-year-old male with a past history of bilateral laser-assisted in situ keratomileusis (LASIK), presented with a decrease in vision in both eyes (BE). Clinical examination showed diffuse corneal haze and interface fluid syndrome (IFS), which was confirmed on anterior segment optical coherence tomography. Intraocular pressure (IOP) measurements obtained with Goldmann applanation tonometer (GAT) were low; however, digital tonometry indicated a raised IOP in BE, which was confirmed by measuring IOP with GAT, outside the peripheral edge of the LASIK flap. Treatment with antiglaucoma medications resulted in complete resolution of the interface fluid. However, due to noncompliance with medications, it recurred and glaucoma showed progression. The patient underwent trabeculectomy with mitomycin C in BE, resulting in improvement in the visual acuity, clear cornea, resolution of interface fluid, and normal IOP, till the last follow-up visit. This case had IFS secondary to episodes of raised IOP, which was diagnosed on careful clinical examination. IOP readings using GAT over the central cornea can give spuriously low readings in IFS. Hence, IOP should be measured in the peripheral cornea to obtain correct IOP readings. Early detection of high IOP and its management is essential to halt glaucoma progression.

Qualitative ultrasound biomicroscopy in glaucoma.

Background: UBM is a high-resolution ultrasound technique which allows non-invasive, in vivo imaging of the anterior segment and iridocorneal angle. Purpose: This video is compilation of short video clips and images which gives description on identification of angle closure due to pupillary block, peripheral anterior synechiae, iris bombe, plateau iris, supra ciliary effusion, and malignant glaucoma. It also shows video demonstrating partially and fully patent iridotomy and features of trabeculectomy bleb. Synopsis: This video summarizes importance of UBM application in angle closure glaucoma to understand its pathophysiology by showing the relationship between the peripheral iris, trabecular meshwork and ciliary processes. Highlights: UBM provides two-dimensional, grayscale images of the angle structures and allows identification of non-pupillary block mechanism in angle closure glaucoma, which can be recorded for qualitative and quantitative analyses. Video Link: https://youtu.be/prsmGnR8jYc.

Quantitative ultrasound biomicroscopy of iridocorneal angle.

Background: Ultrasound biomicroscopy (UBM) is a high-resolution ultrasound technique, which allows noninvasive, in vivo imaging of the ocular anterior segment structures. Purpose: This video gives a description of the identification of the iridocorneal angle structures in the cross-sectional view in a radial scan through a typical ciliary process and a guide toward measuring the angle parameters. Synopsis: UBM provides two-dimensional, grayscale images of the iridocorneal angle. The real-time image is displayed on a video monitor and can be recorded for qualitative and quantitative analysis. The angle parameters can be measured by in-built calipers in the machine software and manipulated by the examiner. Highlights: This video demonstrates UBM caliper positions as displayed on the monitor and marked by the examiner for the measurement of various anterior segment parameters of the eye. Video link: https://youtu.be/WTXMupYoyww.

Qualitative ultrasound biomicroscopy of the normal anterior segment.

Background: Ultrasound biomicroscopy (UBM) is a high-resolution ultrasound technique that allows noninvasive, in vivo imaging of the ocular anterior segment structures. Before interpreting the UBM images of the diseased eyes, it is essential to understand the structures seen in the UBM image of the normal eye. Purpose: This video is a compilation of short video clips that gives description of identification of the anterior segment structures in the axial scan, a cross-sectional view through the anterior chamber angle region of a normal subject in a radial scan, and identification of ciliary processes in the transverse scan. Synopsis: UBM provides two-dimensional, grayscale images of the various anterior segment structures and allows all these structures to be imaged simultaneously, in their normal state, as they occur in the living eye. The real-time image is displayed on a video monitor and can be recorded for qualitative and quantitative analysis. Highlights: The video gives an overview of identification of normal anterior segment structures on UBM. Video link https://youtu.be/3KooOp2Cn30.

Imaging iridotrabecular contact in angle closure.

Background: With ultrasound biomicroscopy (UBM), radial scans are taken by using a typical ciliary process, to show the details of the iridocorneal angle, the anterior surface of the ciliary body, and its relation to the posterior iris. Appositional closure represents potentially reversible contact between the peripheral iris and trabecular meshwork. The appositional closure can further be classified according to the configuration of iridotrabecular contact (ITC). UBM can be performed in dark and light conditions, which has been shown to be useful for detecting changes in iridocorneal angle configuration associated with dark and light. Purpose: To image ITC configuration in appositional angle closure and also image iridocorneal angle in dark and bright light room illumination. Synopsis: UBM demonstrates two types of ITC configuration in appositional closure which are, B-type and S-type. It can also demonstrate the presence of sinus of Mapstone in S-type of ITC. Highlights: UBM allows imaging of dynamic changes in the iris and shows that the degree of appositional angle closure is a dynamic process that can change rapidly depending on the lighting conditions. Video link: https://youtu.be/tgN4SLyx6wQ.

Radial peripapillary capillary network in optic disc anomalies with abnormal tissues on disc surface.

Background: Optic disc anomalies with abnormal tissue on the disc surface includes, myelinated nerve fiber, optic disc drusen, and Bergmeister papillae. Imaging the radial peripapillary capillary (RPC) network in optic disc anomalies with optical coherence tomography-angiography (OCTA) can give information on the RPC network in these conditions. Purpose: This video describes the OCTA of optic nerve head and RPC network using the angio disc mode in cases of optic disc anomalies with abnormal tissue on the disc surface. Synopsis: This video presents characteristic features of RPC network in one eye each of myelinated nerve fiber, optic disc drusen, and Bergmeister papillae. Highlights: OCTA in optic disc anomalies with abnormal tissue on the disc surface show a dense RPC microvascular network. OCTA is an effective imaging modality to study vascular plexus/RPC and their alteration in these disc anomalies. Video link: https://youtu.be/zlflgijy56c.