Objective: We determined the diagnostic accuracies of the mydriatic, monoscopic, iPhone 6s+ optic nerve photographs with a 20D lens and the Melbourne Rapid Fields (MRF) visual fields iPad application. Methods: This was a prospective, cross-sectional, single-center study involving 47 non-glaucomatous and 49 glaucomatous eyes. Each eye underwent 2 visual field tests: MRF iPad application and the Humphrey Field Analyzer (HRF). Mydriatic photographs of the fundus were taken with two devices: an iPhone 6s+ combined with a 20 D lens and the Visucam 500 fundus camera. All printouts were evaluated by 2 independent, masked glaucoma specialists. Diagnostic accuracies between the modalities were computed. Agreements between different parameters of both devices were analyzed using Cohen’s kappa test. Results: Smartphone-based (iPhone 6s+) fundus photos had an overall sensitivity of 100%, specificity of 89.36%, positive predictive value (PPV) of 89.36% and negative predictive value (NPV) of 100%, with all kappa values between graders of each parameter above 0.61. Tablet-based Melbourne Rapid Fields test had a sensitivity of 81.82%, specificity of 86.54%, PPV of 83.72% and NPV of 84.91%, showing good agreement with the HRF with a kappa value of 0.68 ± 0.07. Conclusion Smartphone-based fundus photography and tablet-based visual field tests are comparable to the standard fundus photos and visual field tests in evaluating the optic nerve and visual field. These portable devices are reliable and appropriate tools for diagnosing glaucoma and can be used for documentation and testing in remote areas and in a wider range of settings.
Fundus Oculi

Slit lamp adapter is an important optical delivery system of laser photocoagulator. It can transmit laser and change the diameter size of the laser spot. According to the continuable zoom principle of extender lens, using cam mechanical adjust structure to change the diameter size of the laser spot. The diameter size changes from 50 microm to 500 microm.
Fundus Oculi ; Laser Therapy ; instrumentation

A new enhancement method is proposed based on the characteristics of fundus images in this paper. Firstly, top-hat transform is utilized to weaken the background. Secondly, contrast limited adaptive histogram equalization (CLAHE) is performed to improve the uneven illumination. Finally, two-dimensional matched filters are designed to further enhance the contrast between blood vessels and background. The algorithm was tested in DIARETDB0 databases and showed good applicability for both normal and pathological fundus images. A new no-reference image quality assessment method was used to evaluate the enhancement methods objectively. The results demonstrated that the proposed method could effectively weaken the background, increase contrast, enhance details in the fundus images and improve the image quality greatly.
Algorithms ; Contrast Media ; Fundus Oculi ; Humans ; Image Enhancement

With regard to the large amount of calculation in image mosaic algorithm, an image mosaic algorithm based on extended phase correlation of edge is presented. The improved wavelet edge detection algorithm is to detect edge of blood vessels. Then the image translation, rotation and scale changes are calculated by the extended phase correlation method. These parameters are utilized to stitch images. Finally, image fusion can be achieved by fade-in-fade-out method. It is proved by experiments that this algorithm is simple to calculate, and can effectively achieve the image mosaic.
Algorithms ; Fundus Oculi ; Image Processing, Computer-Assisted ; methods

Based on the Gullstrand I model eye, a simplified model eye for testing fundus imaging device is designed. The model eye can reach the following requirements:(1) The refractive characteristics of the ocular refractive tissue are simulated, and the equivalent focal length in air is 17 mm; (2) The differences between relative refractive index differences of the adjacent materials of the simplified model eye and relative refractive index differences of any adjacent two layers (cornea and aqueous humor, aqueous humor and lens, lens and vitreous body) of the Gullstrand I model eye are not more than 1%; (3) In the case of the incident aperture diameter of 3 mm, the differences of radii of the diffuse spots formed by the paraxial light and the axial light are not more than 15%; (4) The differences of angles of chief ray and tangent line of the fundus are not more than 1°; (5) In the case of the incident aperture diameter of 3 mm, the differences of MTF values of the near axis light are not more than 0.1. The simplified model eye can be expected to be used for testing fundus imaging device instead of the test method in ISO 10940:2009 Ophthalmic instruments-Fundus cameras.
Cornea ; Fundus Oculi ; Lens, Crystalline ; diagnostic imaging ; Refraction, Ocular

A case with typical skin lesions of incontinentia pigmeti showed progressing retinal vascular abnormalities. So cryotherapy was done on avascular peripheral retina, and retinal vascular changes ceased. We propose that cryotherapy may be a good treatment method for progressing retinal vascular lesions of incontinentia pigmenti.
*Cryosurgery ; Female ; Fundus Oculi ; Humans ; Incontinentia Pigmenti/*surgery ; Infant, Newborn ; Retinal Diseases/*surgery

Microaneurysm is the initial symptom of diabetic retinopathy. Eliminating this lesion can effectively prevent diabetic retinopathy in the early stage. However, due to the complex retinal structure and the different brightness and contrast of fundus image because of different factors such as patients, environment and acquisition equipment, the existing detection algorithms are difficult to achieve the accurate detection and location of the lesion. Therefore, an improved detection algorithm of you only look once (YOLO) v4 with Squeeze-and-Excitation networks (SENet) embedded was proposed. Firstly, an improved and fast fuzzy c-means clustering algorithm was used to optimize the anchor parameters of the target samples to improve the matching degree between the anchors and the feature graphs; Then, the SENet attention module was embedded in the backbone network to enhance the key information of the image and suppress the background information of the image, so as to improve the confidence of microaneurysms; In addition, an spatial pyramid pooling was added to the network neck to enhance the acceptance domain of the output characteristics of the backbone network, so as to help separate important context information; Finally, the model was verified on the Kaggle diabetic retinopathy dataset and compared with other methods. The experimental results showed that compared with other YOLOv4 network models with various structures, the improved YOLOv4 network model could significantly improve the automatic detection results such as F-score which increased by 12.68%; Compared with other network models and methods, the automatic detection accuracy of the improved YOLOv4 network model with SENet embedded was obviously better, and accurate positioning could be realized. Therefore, the proposed YOLOv4 algorithm with SENet embedded has better performance, and can accurately and effectively detect and locate microaneurysms in fundus images.
Algorithms ; Diabetic Retinopathy/diagnostic imaging* ; Fundus Oculi ; Humans ; Microaneurysm/diagnostic imaging*

Solid-state multi-wavelength laser equipment is the treatment device with selected wavelength Nd: YAG laser frequency technology, integrated red (659 nm), yellow (589 nm) and green (532 nm) of three solid-state lasers. The device is designed by the accurate controlled laser output system, precision optical and electronic control through the optical coupler into the optical fiber transmission system. It's combined with an eye slit lamp integration of high precision, good stability stability for all solid-state multi-wavelength lasers equipment.
Equipment Design ; Fundus Oculi ; Laser Therapy ; instrumentation ; Lasers, Solid-State ; therapeutic use ; Retinal Diseases ; surgery

OBJECTIVETo observe the clinical manifestations of bullous retinal detachment and analyze the etiological factors.

METHODSA retrospective analysis of the clinical data was conducted in 22 patients with multifocal retinal pigment epitheliopathy (DRPE) and big bullous retinal detachment (BBRD), who were admitted between 2003 and 2008 in Zhongshan Ophthalmic Center with the diagnoses established by ocular fundus examination, fundus fluorescein angiography (FFA) and/or indocyanine green angiography (ICGA).

RESULTSThe patients included 15 men (68%) and 7 women (32%), with a mean age at the initial visit of 42 years, ranging from 25 to 64 years. Four patients (18%) received previously systemic corticosteroid therapy, and 2 of them used corticosteroids before retina detachment, 1 suffered progression of retinal detachment after corticosteroid therapy, and the other developed retinal detachment in the healthy eye during the therapy. Multifocal bullous retinal detachment was diagnosed as diffuse pigment epitheliopathy (DRPE) in 9 cases. Most of the 13 cases of big bullous retinal detachment had poor vision after operation and laser therapy.

CONCLUSIONBullous retinal detachment occurs most frequently in mid-life and more often in men than women. Abnormal retinal pigment epithelium (RPE) and hyperpermeability of the choroid vessels are associated with its occurrence. Systemic corticosteroid therapy and mental stress may induce and aggravate this disease. Early medication and laser therapy are effective, and surgical intervention may save only part of the vision in advanced cases.

Adult ; Female ; Fundus Oculi ; Humans ; Male ; Middle Aged ; Retinal Detachment ; diagnosis ; etiology ; pathology ; therapy ; Retrospective Studies

The precise estimation of blood vessel centerline and width is a prerequisite condition for the quantitative and visualized diagnosis of blood vessel disease in fundus images. In this paper, a retinal blood vessel segmentation algorithm based on centerline extraction is proposed. According to the characteristics of the fundus image and retinal blood vessels, the image is convoluted with the masks of discrete Gaussian partial derivative kernels. The centerline is determined by differential geometric properties of the blood vessels and the width is also calculated. The precision of our method can reach sub-pixel level with a fast computation speed. The experiments on several kinds of fundus images showed that the method worked quickly and accurately.
Algorithms ; Fundus Oculi ; Humans ; Image Enhancement ; methods ; Retinal Vessels ; anatomy & histology