Classifying Three Stages of Cataract Disease using CNN

مقدمة:   من بين العديد من الأمراض التي تصيب شبكية العين هو الساد . يعتبر مرض الساد من أخطر مشاكل الصحة العامة الدوائية في الدول النامية.  يمكن أن يحدث  دون التسبب في أي أعراض. وهو يعتبر أحد الأسباب الرئيسية للعمى أو عدم وضوح الرؤية لكبار السن. لذلك ، فإن الاكتشاف الدقيق والمبكر لإعتام عدسة العين حسب شدة الحالة مطلوب للحفاظ على الرؤية ومنع الزيادة العالمية في العمى الناجم عن إعتام عدسة العين. كما هو الحال مع معظم الأمراض المتعلقة بالعيون، فقد ثبت أن العلاجات والتشخيص المبكر يمنعان فقدان البصر . و بالمقارنة مع طرق التشخيص اليدوية، تساعد أنظمة تحليل الشبكية الأوتوماتيكي في تقليل وقت للمرضى وتقليل التكلفة. اكتسبت طرق الكشف عن مرض عتمة العين المبنية على استخدام الذكاء الاصطناعي اهتمامًا كبيرًا في المجتمع العلمي. ينتج هذا البحث طريقة فعالة وقوية للتشخيص التلقائي لإعتام عدسة العين باستخدام الشبكة العصبية التلافيفية (CNN) لاكتشاف وتصنيف الساد تلقائيًا في صور قاع العين. يستخدم محسن آدم ومجموعة بيانات (ODIR) لتدريب النموذج. تتفوق الطريقة المقترحة على أحدث أنظمة الكشف عن المياه البيضاء بمتوسط ​​دقة 100٪ لفئتين (عادي، إعتام عدسة العين)، 96.9٪ لأربع فئات (عادي، خفيف، معتدل، شديد) وفقًا للنتائج التجريبية. طرق العمل: باستخدام شبكة Convolution العصبية (CNN) لاكتشاف وتصنيف إعتام عدسة العين تلقائيًا في صور قاع العين.. الاستنتاجات:    حيث يقترح هذا البحث نظام التشخيص الآلي لإعتام عدسة العين باستخدام الشبكة العصبية العميقة (DCNN). تمت معالجة مجموعة بيانات الساد لصور قاع العين مسبقًا وتحسينها لجعل مجموعة البيانات أكثر ملاءمة لتغذية الشبكة العميقة في البداية. تعمل الشبكة المقترحة في طبقات مختلفة، ودوال التنشيط ، ودوال الخسارة، وخوارزميات التحسين من أجل تقليل تكاليف الحوسبة مع الحفاظ على دقة النموذج. استخدم النظام المقترح طرق تكبير متعددة للصور ، ثم طبق النظام على هذه الصور المعززة لتقليل مشكلة فرط التجهيز وتحسين كفاءة النظام المقترح ، حيث تم الحصول على أفضل دقة لتصنيف 96.9 بالمائة لصور قاع العين التي تمت زيادتها قاعدة بيانات ODIR ، ولكن بنسبة 94 في المائة فقط عند تطبيق النظام على صور قاع العين الأصلية. عند مقارنته بأعمال أخرى مماثلة، كان أداء هذا النظام رائعًا. نظرًا لأن هذا النهج كان فعالًا للغاية من حيث التكلفة وتوفير الوقت اللازم لطبيب العيون، فقد كان فعالاً من حيث الوقت، قادراً على اكتشاف إعتام عدسة العين بشكل أسرع ودقيق مع عدد أقل من المعاملات المستخدمة في الشبكة وطاقة كمبيوتر أقل. كذلك في صور قاع الشبكية، فإن الطريقة المقترحة قادرة على اكتشاف مراحل الساد. وتم الكشف عن مراحل إعتام عدسة العين (خفيفة، معتدلة، وشديدة) بواسطة نظام DCNNs المقترح.      Among the many diseases that affect the retina, a cataract. It is one of the most serious pharmacological public health issues in developing nations, it can develop without causing any symptoms. It is one of the prime reasons for blindness or blurred vision for senior citizens. Therefore, accurate and early detection of cataracts depending on the severity of the condition is required to preserve vision and prevent the global increase in blindness caused by cataracts. As with most of the diseases related to the eyes, treatments, and early diagnosis have been shown to prevent visual loss and blindness. Compared with the manual diagnostic methods, automated retinal analysis systems help save patients' time, vision and cost. Artificial intelligence-based cataract detection methods have gained a lot of attention in the scientific community. This research produces an efficient and robust method for the automatic diagnosis of cataract by using Convolution Neural Network (CNN) for detection and classification cataract grading automatically in fundus images. It used Adam optimizer and (ODIR) dataset to train the model. The suggested method beats state-of-the-art cataract detection systems with an average accuracy of 100 % for two classes (Normal, Cataract) ,96.9% for four classes (Normal, Mild, Moderate, Sever) according to experimental results.  Materials and Methods: Used Convolution Neural Network for detection and classification cataract grading automatically in fundus images.  Results: The suggested method beats state-of-the-art cataract detection systems with an average accuracy of 100 %  for two classes (Normal, Cataract) ,96.9% for four classes (Normal, Mild, Moderate, Sever) according to experimental results. Conclusion: The proposed network looked at different layers, activation functions, loss functions, and optimization algorithms in order to reduce computing costs while maintaining model accuracy. The proposed system used multi-image augmentation methods, then implemented the system on these augmented images to decrease the issue of overfitting and to improve the efficiency of the suggested system, as best accuracy obtained for classification 96.9 percent was get for fundus images which augmented of ODIR dataset, but only 94 percent when the system was applied to the original fundus images. When compared to other similar works, this system performed admirably. Because this approach was extremely cost- effective, accurate, and ophthalmologists, time-efficient were able to detect cataract more quickly and accuracy with fewer parameters and less computer power.  In retinal fundus images, the suggested approach is able to detect cataract phases. The detection of cataract stages (mild, moderate, and severe) will be done by the DCNNs system

Accelerating precision ophthalmology: recent advances

Introduction: The future of ophthalmology is precision medicine. With a growing incidence of lifestyle-associated ophthalmic disease such as diabetic retinopathy, the use of technology has the potential to overcome the burden on clinical specialists. Advances in precision medicine will help improve diagnosis and better triage those with higher clinical need to the appropriate experts, as well as providing a more tailored approach to treatment that could help transform patient management. Areas covered: A detailed literature review was conducted using OVID Medline and PubMed databases to explore advances in precision medicine within the areas of retinal disease, glaucoma, cornea, cataracts and uveitis. Over the last three years [2019–2022] are explored, particularly discussing technological and genomic advances in screening, diagnosis, and management within these fields. Expert opinion: Artificial intelligence and its subspecialty deep learning provide the most substantial ways in which diagnosis and management of ocular diseases can be further developed within the advancing field of precision medicine. Future challenges include optimal training sets for algorithms and further developing pharmacogenetics in more specialized areas

Cataract, macular characteristics and assessing lens opacities

Age-related macular degeneration and cataract are very common causes of visual impairment in the elderly. Macular pigment optical density is known to be a factor affecting the risk of developing age-related macular degeneration but its behaviour due to light exposure to the retina and the effect of macular physiology on this measurement are not fully understood. Cataract is difficult to grade in a way which reflects accurately the visual status of the patient. A new technology, optical coherence tomography, which allows a cross sectional slice of the crystalline lens to be imaged has the potential to be able to provide objective measurements of cataract which could be used for grading purposes. This thesis set out to investigate the effect of cataract removal on macular pigment optical density, the relationship between macular pigment optical density and macular thickness and the relationship between cortical cataract density as measured by optical coherence tomography and other measures of cataract severity. These investigations found: 1) Macular pigment optical density in a pseudophakic eye is reduced when compared to a fellow eye with age related cataract, probably due to differences in light exposure between the eyes. 2) Lower macular pigment optical density is correlated with thinning of the entire macular area, but not with thinning of the fovea or central macula. 3) Central macular thickness decreases with age. 4) Spectral domain optical coherence tomography can be used to successfully acquire images of the anterior lens cortex which relate well to slit lamp lens sections. 5) Grading of cortical cataract with spectral domain optical coherence tomography instruments using a wavelength of 840nm is not well correlated with other established metrics of cataract severity and is therefore not useful as presented as a grading method for this type of cataract

Digital Images Assessment of Posterior Capsule Opacification

A digital imaging system has been developed for the objective assessment of severity and morphology of posterior capsule opacification (PCO). The system is based on a Nikon FS-2 photo slit-lamp and a Kodak DCS 100 digital camera system. The slit-lamp was used with conventional (forward) illumination and studies were carried out to determine the best combination of slit-lamp and camera parameters to optimize the images. These were found to be a slit beam width of 3.5mm, slit angle of 45°, film speed (ISO) of 1600 for the camera and 800 for the digital storage unit (DSU), exposure compensation 0, flash intensity 2 and a magnification of 25x. A fixation stimulus was developed since it was shown to decrease the variability of the images and reduce the possibility of unwanted reflexes affecting the area of interest. In all cases a central 3mm x 3mm area of the posterior capsule, centred on the pupil, was analysed. The image processing software used throughout the work was Image Pro+ v4.51 (Media Cybernetics, Silver Spring, MD). For validating the system, subjects who had previously had uncomplicated cataract surgery were recruited from the Nd:YAG capsulotomy clinics of the Royal Eye Unit at Kingston. Intra-observer repeatability was assessed by taking 6 repeat images for each of 10 subjects. The coefficient of variation for total spectral power in the image, a measure of the severity of opacification, was 1.5%. Inter-observer repeatability was tested for 3 observers, an ophthalmologist, an optometrist and a non-clinician, by recording 2 images for each observer for each of 9 subjects. There was a 6 fold increase in the limits of agreement when the non-clinician was involved indicating that suitable training is required to use the system in a repeatable fashion. Severity of opacification was measured by calculating the log of the total spectral power in the Fourier Transform image of the area of interest. Results on 45 eyes correlated well with subjective grading of PCO by an experienced ophthalmologist: Within the 3 morphological groups, fibrotic, mixed and pearl, correlation coefficients of 0.909, 0.864 and 0.713 were found, which were all statistically significant. Morphological classification was carried out by developing a simple expert system. The rules in the knowledge base were derived from known histological features of PCO and clinically observed changes. The weighted kappa score for agreement between the objective classifier and an experienced ophthalmologist was 0.61 indicating a good level of agreement. However 14 out of 45 cases did not exhibit agreement. It may be possible with further work to improve the classification rules to reduce this number. New methods have been presented for objectively measuring the severity and morphologically classifying PCO. The system developed in this work shows distinct potential for use within primary care environments since it uses techniques and instruments whose operation is familiar to all practitioners involved. The validation studies presented here demonstrate variability in the measurements that is largely in agreement with previously published systems

Femtosecond lasers in corneal and refractive surgery

Femtosecond lasers were introduced in ophthalmology initially for flap creation for LASIK. This thesis describes a body of work undertaken by the author exploring the possibility of using these lasers in corneal and refractive surgery. The use of the femtosecond laser in corneal and refractive surgery offered the prospect of better precision with respect to their accuracy in depth cut, and the smoothest of lamellar interface. The development of multiple laser platforms allowed us to perform comparative studies in both ex vivo/animal and clinical studies and to explore the prospect of a new refractive procedure, lenticule extraction and also lenticule re-implantation. The laser proved to be accurate in its vertical depth cutting and following optimization was able to cut a smoothe lamellar interface. The clinical study showed the laser to be safe and effective. The comparative studies showed the superiority of the lower energy femtosecond laser on IOP rise, without compromising on clinical outcomes, which were the same for both lasers. Femtosecond laser lenticule creation was optimised in animal models and then shown to be safe and efficacious in a clinical study. The wound healing benefits of an ‘all in one’ femtosecond laser procedure were evident, in both animal as well clinical studies. Lenticule reimplantation was shown to be effective in both the rabbit and monkey models. The use of the femtosecond laser is set to increase in ophthalmology. The work in this thesis has provided fundmental ex vivo, animal and clinical benefits on the the use of femtosecond lasers in corneal and refractive surgery. It has also envisioned a concept of lenticule re-implantation for future clinical use

Accelerating precision ophthalmology: recent advances

Introduction The future of ophthalmology is precision medicine. With a growing incidence of lifestyle-associated ophthalmic disease such as diabetic retinopathy, the use of technology has the potential to overcome the burden on clinical specialists. Advances in precision medicine will help improve diagnosis and better triage those with higher clinical need to the appropriate experts, as well as providing a more tailored approach to treatment that could help transform patient management. Areas covered A detailed literature review was conducted using OVID Medline and PubMed databases to explore advances in precision medicine within the areas of retinal disease, glaucoma, cornea, cataracts and uveitis. Over the last three years [2019 – 2022] are explored, particularly discussing technological and genomic advances in screening, diagnosis, and management within these fields. Expert opinion Artificial intelligence and its subspecialty deep learning provide the most substantial ways in which diagnosis and management of ocular diseases can be further developed within the advancing field of precision medicine. Future challenges include optimal training sets for algorithms and further developing pharmacogenetics in more specialized areas

Anterior segment anomalies and effects on visual quality

The tear film, cornea and lens dictate the refractive power of the eye and the retinal image quality is principally defined by diffraction, whole eye wavefront error, scatter, and chromatic aberration. Diffraction and wave aberration are fundamentally pupil diameter dependent; however scatter can be induced by refractive surgery and in the normal ageing eye becomes an increasingly important factor defining retinal image quality. The component of visual quality most affected by the tear film, refractive surgery and multifocal contact and intraocular lenses is the wave aberration of the eye. This body of work demonstrates the effects of each of these anomalies on the visual quality of the eye. When assessing normal or borderline self-diagnosed dry eye subjects using aberrometry, combining lubricating eye drops and spray does not offer any benefit over individual products. However, subjects perceive a difference in comfort for all interventions after one hour. Total higher order aberrations increase after laser assisted sub-epithelial keratectomy performed using a solid-state laser on myopes, but this causes no significant decrease in contrast sensitivity or increase in glare disability. Mean sensitivity and reliability indices for perimetry were comparable to pre-surgery results. Multifocal contact lenses and intraocular lenses are designed to maximise vision when the patient is binocular, so any evaluation of the eyes individually is confounded by reduced individual visual acuity and visual quality. Different designs of aspheric multifocal contact lenses do not provide the same level of visual quality. Multifocal contact lenses adversely affect mean deviation values for perimetry and this should be considered when screening individuals with multifocal contact or intraocular lenses. Photographic image quality obtained through a multifocal contact or intraocular lens appears to be unchanged. Future work should evaluate the effect of these anomalies in combination; with the aim of providing the best visual quality possible and supplying normative data for screening purposes

Quantifying ocular inflammation in uveitis using optical coherence tomography

Inflammation is the key underlying physiological process in uveitis. It drives the onset of acute flares, causes permanent structural damage and can result in sight-threatening complications. Being able to accurately detect and measure changes in inflammatory activity is crucial for managing uveitic flares and rationalising therapeutic decisions. Unfortunately, many of the current methods for quantifying inflammation are imperfect, due to the fact that they are based on subjective and unreliable clinician estimates. In this thesis, I evaluated the potential for imaging-based technologies such as optical coherence tomography (OCT) to measure key markers of intraocular inflammation in uveitis. Whilst several key markers of inflammation are recognised, this thesis focuses on those with an existing clinical standard, which can be used as a comparator or reference test (anterior chamber cells, anterior chamber flare and vitreous haze). I conducted a series of systematic reviews evaluating potential instrument-based techniques for measuring anterior chamber cells, anterior chamber flare and vitreous inflammation, respectively. These identified OCT and laser flare photometry as potential instruments for measuring anterior chamber cell and flare, and OCT and retinal photography for measuring vitreous inflammation. However, the interpretation of results in each review was limited by relatively few studies and the inclusion of highly heterogenous uveitic patient populations, varying severities of disease, and lack of a standardised image acquisition protocol. Second, in the prospective study, OCTAVE (OCT-assisted vitreous evaluation), I found that our custom OCT-based vitreous analysis technique (EQUIP) demonstrated good repeatability in healthy and uveitic eyes, was able to detect vitreous inflammation and was associated with the current clinical vitreous haze grading. The EQUIP measurement was able to predict visual acuity whereas the current standard method (clinician grading 3 using the National Eye Institutevitreous haze scale) could not. Whilst these results were encouraging, there remains substantial overlap in the OCT measurement between NEI vitreous haze grades. It is not clear whether this is due to poor signal-to-noise ratio of the OCT technique, or a sign of poor reliability of the comparator (clinician-based grading using the NEI vitreous haze scale). Further investigation through longitudinal studies may be able to answer this question. In summary, OCT has demonstrated potential for quantifying inflammation for multiple key measures in uveitis. However, a key limitation for the validation of all instrument-based measures has been the lack of a reliable reference test

The development of excimer laser corneal surgery

Investigations were carried out - including the first systematic studies worldwide - to evaluate the efficacy and safety of argon fluoride excimer laser corneal surgery. These studies comprised 4 phases : A. A laboratory investigation using the laser to smooth irregular cadaver corneal surfaces. B. The development and evaluation of phototherapeutic keratectomy (PTK) for the treatment of superficial corneal pathology. C. A prospective clinical trial to investigate the efficacy and safety of photorefractive keratectomy (PRK) for the treatment of myopia. D. A randomized, prospective, double-masked clinical trial to investigate the role of topical corticosteroids following PRK. RESULTS A. CORNEAL SURFACE SMOOTHING Selective excimer laser photoablation of irregular cadaver corneal surfaces demonstrated that these could be smoothed in a highly precise way leaving a regular surface similar to that of normal cornea. B. PHOTOTHERAPEUTIC KERATECTOMY (PTK) 25 patients with superficial corneal pathology were treated. A marked improvement in corneal contour or transparency was demonstrated in all patients with corresponding improvement in visual acuity, glare or comfort. C. PHOTOREFRACTIVE KERATECTOMY (PRK) 120 patients underwent PRK for treatment of myopia. Initial mean overcorrection was followed by regression to an undercorrected endpoint. Regression was greater when higher degrees of myopia were treated. Complications included anterior stromal "haze" (95% of patients), night halo effects (78%), and loss of visual acuity (15%). D. THE ROLE OF TOPICAL CORTICOSTEROIDS POST-PRK 113 patients received either intensive topical corticosteroid or placebo after PRK. A beneficial effect on refraction, sustained only during the period of administration, was found in the corticosteroid group. No statistically significant difference in anterior stromal haze was demonstrated. This thesis details the methodology and results for each phase of this study. The discussion sections compare PTK and PRK with traditional methods of superficial keratectomy and refractive corneal surgery, with the aim of assessing the future potential of laser corneal surgery