A pathological indicator for dysthyroid optic neuropathy: tritan color vision deficiency

PURPOSE To investigate the sensitivity of the color vision test by Arden in patients with dysthyroid optic neuropathy (DON) to improve diagnosis. METHODS In this observational, retrospective study, we included the medical records of 92 eyes (48 patients) with diagnosis of DON between 2008 and 2019 in order to evaluate the full spectrum of findings from the color vision test by Arden, and to determine potential importance of this test. Thirty-five patients were female, and 13 patients were male. The mean age was 58.0~years (range: 34-79) at the time of the DON diagnosis. RESULTS Forty-one eyes displayed relatively good BCVA with ≤ 0.2 LogMAR. We found a protan value exceeding the threshold of ≥ 8% in 57 eyes (30 patients) at the time of the diagnosis. The sensitivity of protan was 61.9% (95% CI 51.2-71.8%), while that of tritan was a striking 98.9% (95% CI 94.1-99.9%). We discovered one pathological sign, tritan deficiency (based on a threshold of ≥ 8%) consistently in all eyes but one at the time of the diagnosis, regardless of the visual field defects or any changes in best-corrected visual acuity (BCVA). CONCLUSION We found blue-yellow (tritan) deficiency, to be a sensitive and reliable indicator of dysthyroid optic neuropathy. We conclude that, in cases with suspected DON, a color vision test that can detect tritan deficiency is an essential tool for the adequate assessment, diagnosis, and treatment of DON

Practical Ophthalmology

The study guide is intended to train students of higher medical educational institutions of the fourth level of accreditation on the specialty “Medicine”, interns, residents and masters. The guide is a new progressive step in teaching the discipline “Ophthalmology”

NEW INSIGHTS INTO SCHIZOPHRENIA: A LOOK AT THE EYE AND RELATED STRUCTURES

Background: Schizophrenia is a multifactorial neurodevelopmental disorder associated with cognitive dysfunction and changes in primary sensory processing. This article aims to explore the current insights into the relationship between schizophrenia and different visual disturbances. Methods: To provide a literature review of visual impairments in schizophrenia, we performed a PubMed/MEDLINE and Scopus search to identify all articles in English on the topic up to the end of 2018. Results: Multiple retinal functional and structural abnormalities are found in patients with schizophrenia. Wider retinal venules suggest chronically insufficient brain supply of oxygen and this could contribute to the occurrence of psychotic symptoms. Optical coherence tomography studies showed that retinal nerve fiber layer, macular thickness, and macular volume were significantly lowered in the chronic phase of schizophrenia. Results from electroretinogram recordings have demonstrated different declinations such as abnormalities of a - wave activity in the photoreceptors or b - wave activity in the bipolar and Muller cells. Abnormalities in eye movements, such as a notable decrease in saccades and smooth pursuit eye movements, are one of the most reliable and reproducible impairments associated with schizophrenia. Disrupted visual processing of the magnocellular pathway may result in a decrease of contrast sensitivity, sensory processing, orientation discrimination, visual integration, trajectory and spatial localization, backward masking and motion tracking. Visual perceptual abnormalities occur in more than 60% of schizophrenic patients and these are visual hallucinations, perceptual distortion of colors, shapes and light intensity, decrease in contour integration and surround suppression. Other, frequently present eye disorders include impaired visual acuity, strabismus and nystagmus. Conclusion: Visual impairments are one of the most important features of schizophrenia, which could help in defining the disease state and assigning appropriate treatment

Ocular manifestations in patients with chronic kidney disease : a hospital based study

INTRODUCTION: Chronic kidney disease (CKD) is a worldwide health problem. There is a rising incidence of renal failure due to chronic kidney disease and this phenomenon is common in both the developed and under developed countries. There is a significant mortality and morbidity associated with this condition and it drastically reduces the quality of the patient’s life. Normal functions of the kidneys can be affected by a variety of diseases and medical conditions. These cause a reduction in GFR, metabolic imbalances and retention of harmful waste products. A majority of patients progress to end stage kidney disease and may require dialysis or renal transplantation. Chronic kidney disease leads to a lot of systemic effects that affects a variety of systems in the body. The eye also shows changes due to long standing kidney disease. Some systemic diseases such as diabetes, hypertension and auto immune disorders affect the kidneys as well as the eye. Ocular manifestations may arise as a result of the primary diseases causing renal failure or as a result of the secondary effects of renal failure itself. It is thus very difficult to ascertain whether the systemic effects are due to the disease which caused the renal failure or secondary to the changes caused by the kidney disease unless the patient is monitored continuously throughout the course of the disease. AIM OF THE STUDY: Chronic Kidney Disease affects every organ system including the eye. The requirement for a routine ophthalmic examination for all patients with chronic kidney disease and its role in the prevention of visual loss cannot be over emphasized. The aim of the study is to conduct a thorough ocular examination and to study the occurrence of various ocular manifestations exhibited by patients with Chronic Kidney Disease and to analyse the findings. MATERIALS AND METHODS: This is a Cross Sectional, Descriptive, Non interventional, Hospital based study. The period of study was for 15 months, from August 2010 to October 2011. Institutional Ethical Committee approval for conducting the study was obtained. Patients presenting to Department of Nephrology, Stanley Medical College diagnosed with Chronic Kidney Disease were examined for ocular manifestations at the Department of Ophthalmology, Stanley Medical College. Sampling technique was consecutive and 100 patients (200 eyes) were enrolled in this study. Importance of ocular evaluation were explained to the patients. Evaluation procedures were explained and an informed consent was obtained. After obtaining consent 200 eyes of the enrolled patients were examined thoroughly. Results of blood and urine investigations performed at Nephrology department were collected. RESULTS: The age distribution in the study group was more or less even, with the patients in the age group 30 – 39 slightly more than the rest. Mean age of the patients with chronic kidney disease is 44.2. Male patients formed 72% of the total patients in the study group. The average male : female ratio was 2.6:1. CONCLUSION: CKD is the end result of multiple systemic diseases or primary renal disease. During the natural course of the disease it affects multiple systems of the body including the eye. Detailed ocular examination was conducted in 100 patients in varying stages of CKD. In this study hypertension was the single main cause of CKD followed by DM and HT together. In this study most of the patients were having their eyes examined for the first time. This shows the lack of awareness of the importance of early ocular evaluation among the patients. This study is an attempt to assess the ocular status and complications associated with chronic kidney disease. It is intended to highlight the importance of ocular examination in all patients with chronic kidney disease irrespective of the presence of ocular symptoms so that necessary treatment or advice can be given before they cause irreversible visual impairment

The double-edged sword of inflammation in inherited retinal degenerations: Clinical and preclinical evidence for mechanistically and prognostically impactful but treatable complications

We present retrospective data from our clinical research efforts of the past several years alongside a review of past and current clinical and preclinical data independently by several investigators supporting our clinical evidence for the importance of inflammation in inherited retinal degenerations (IRDs). We show how inflammation is a complicating factor in IRDs but, if recognized and managed, also a great opportunity to mitigate disease severity immediately, improve patient prognosis and quality of life, extend the treatment windows for gene-specific and agnostic therapeutic approaches, mitigate the impact of inflammatory complications on the accurate estimate of vision changes in IRD natural history studies, improve the chances of safer outcomes following cataract surgery, and potentially reduce the likelihood of inflammatory adverse events and augment the efficacy of viral vector-based treatment approaches to IRDs. Manuscript contribution to the field. Inflammation has been suspected to be at play in IRDs since the beginning of the 1900s and became a research focus through the early 1990s but was then largely abandoned in favor of genetic-focused research. Thanks to regained cognizance, better research tools, and a more holistic approach to IRDs, the recent reappraisal of the role of inflammation in IRDs has brought back to the surface its importance. A potential confounder in natural history studies and a limiting factor in clinical trials if not accounted for, inflammation can be managed and often offers an opportunity for immediately improved prognosis and outcomes for IRD patients. We present our retrospective clinical evidence for connections with a measurable secondary autoimmune component that can develop in IRDs and contribute to vision loss but is at least in part treatable. We also present ample lines of evidence from the literature corroborating our clinical observations at the preclinical level

Advances in Ophthalmology

This book focuses on the different aspects of ophthalmology - the medical science of diagnosis and treatment of eye disorders. Ophthalmology is divided into various clinical subspecialties, such as cornea, cataract, glaucoma, uveitis, retina, neuro-ophthalmology, pediatric ophthalmology, oncology, pathology, and oculoplastics. This book incorporates new developments as well as future perspectives in ophthalmology and is a balanced product between covering a wide range of diseases and expedited publication. It is intended to be the appetizer for other books to follow. Ophthalmologists, researchers, specialists, trainees, and general practitioners with an interest in ophthalmology will find this book interesting and useful

Causes of visual loss in patients with uveitis

The last major study of causes of vision loss in 600 eyes with uveitis was published over 10 years ago and there have been many advances in treatment over this time. In this thesis I undertook a study of 1594 patients (2593 eyes) with uveitis currently attending the clinic, 75% of whom were aged between 24 and 63 years. The type of uveitis, sight threatening complications that developed and treatment were followed from presentation to final follow up. At presentation, 16% of eyes had BCVA ≤ 6/18 (e.g. 6/18-6/36) and 14% of affected eyes had BCVA 6/60 or worse. At one year follow-up, we found 11% of eyes with vision loss to 6/18-6/36 and 8% of eyes with severe visual loss or blindness. In the group of eyes followed up for 10 years or more, 19% developed severe visual loss or blindness and 16% developed vision loss to 6/18-6/36. Chronic macular damage was the main cause of visual loss, accounting for both for visual impairment and for severe visual loss, accounting for 41% and 36% respectively. Cystoid macular oedema accounted for 29% in visual impairment and 19% in severe visual loss or blindness. When classified by uveitis types, CMO was the main cause of vision loss in intermediate uveitis (38%), glaucoma was the leading cause in anterior uveitis (32%), and chronic macular damage accounted for 46% in posterior/panuveitis. Additionally, I looked at the outcome and subsequent impact on vision of ocular surgery for cataract, glaucoma and vitreo-retinal procedures. Visual prognosis after cataract surgery was favourable in anterior and intermediate uveitis. Eyes which underwent glaucoma surgery had vision stabilised or slightly improved over time. The mean log MAR BCVA prior to glaucoma surgery was 0.53+/- 60, and 0.31+/- 49 at final follow-up visit. (P= 0.012). There was no statistically significant improvement in visual acuity in eyes which had undergone vitreo-retinal procedures. The mean logMAR BCVA were 1.1+/-0.82 and 0.87+/-0.80 respectively pre-operative and at last post- op visit. (P=0.28) The 3rd main results chapter looks at patients presenting with retinal vasculitis who had ischemia and the long term outcome for these eyes. Of the 106 eyes which developed ischemia, 24% had vision loss to 6/18-6/36 at presentation, 23% of these had BCVA 6/60 or worse. Chronic macular damage was the main cause of visual impairment and accounted for 36%, macular ischemia accounted for 67% of severe visual loss or blindness. I found that in most eyes with ischemia, visual loss developed early in the first 5 years and do not worsen with time

A phase II, double blind, randomised, placebo-controlled trial of neuroprotection with phenytoin in acute optic neuritis

Acute optic neuritis is a common and often presenting feature of multiple sclerosis, and attacks can lead to persistent visual impairment through neurodegeneration in the retina and optic nerve. The acute inflammatory lesion in the optic nerve resembles the demyelinating plaques elsewhere in the CNS. As with other MS relapses, corticosteroids have no or little impact on the extent to which vision recovers nor do they prevent optic nerve atrophy on MRI or improve VEP latency after an attack of optic neuritis. There is currently no treatment for the acute phase of the disease to improve long-term visual outcome, and in this context neuroprotection remains a major unmet need. Progress in the development of potential neuroprotective therapies in optic neuritis and MS relies upon the identification of key mechanisms and treatment targets. Among possible mechanisms of neurodegeneration, there is growing evidence of a cascade of accumulation of sodium ions in demyelinated axons that arises from neuronal energy failure leading to the reverse operation of the Na+ /Ca2+ exchanger and subsequent toxic accumulation of injurious calcium ions. Inhibition of voltage-gated sodium channels is neuroprotective in preclinical models of inflammatory demyelination. The anterior visual system has many advantages for testing neuroprotective treatments in MS. In particular, the retinal nerve fibre layer is a relatively pure compartment of unmyelinated axons whose thickness can be measured sensitively and non-invasively using optical coherence tomography making it an attractive biomarker of axonal loss. In this thesis I investigated whether early and sustained sodium channel inhibition with phenytoin is neuroprotective in acute optic neuritis. 86 people were randomized within 2 weeks of optic neuritis symptom onset to receive phenytoin or placebo for 3 months. Retinal nerve fibre layer (RNFL) thickness and macular volume (MV) were measured at baseline, then 6 months later, using optical coherence tomography. Visual function, optic nerve MRI, and visual evoked potentials were also measured. The primary outcome was mean RNFL thickness in the affected eye at 6 months, adjusted for fellow eye RNFL thickness at baseline. In the intention to treat comparison, average affected eye RNFL thickness at 6 months was 7.15 µm greater in the active group (n=39) vs. placebo (n=42), a 30% protective treatment effect (p=0.021). Adjusted MV was 0.20 mm3 greater in the active group, a 34% treatment effect (p=0.005). There was also a near significant treatment effect on optic nerve crosssectional area (p=0.06). Per protocol comparisons showed similar treatment effects. Treatment did not affect visual outcome. These findings support the concept of neuroprotection with phenytoin in acute optic neuritis. Inhibition of voltage-gated sodium channels could also be neuroprotective in other relapses of multiple sclerosis, and further investigation of its effect is warranted in this major area of unmet therapeutic need

Ocular health of cocoa farmers in Ghana : an assessment and intervention study.

Ph. D. University of KwaZulu-Natal, Durban 2014.Background: Cocoa farmers are known to face a lot of ocular health hazards such as chemicals, ultraviolet radiations, farm equipment, plants, dust and allergens among others in the field of work. This study sought to examine and understand the factors that affect the ocular health of cocoa farmers in Ghana in order to improve their knowledge and awareness on ocular health and safety practices through a training intervention. Methods: The study employed two quantitative approaches: a cross-sectional survey and a quasi- experimental pre-post-test study design. The cross-sectional study involved administration of a questionnaire and conducting a comprehensive eye examination among participants, while the pre-post-test study used a structured questionnaire to gather baseline knowledge and post training knowledge on ocular health and safety practices among the participants to establish a change. A multistage random sampling approach was used to select participants from four cocoa growing districts of Ghana. Results: Five hundred and fifty-six, out of the 576, who were recruited for the first phase of the study, met the inclusion criteria, giving an eligibility rate of 96.5%. The participants consisted of 359 (64.6%) males and 197 (35.4%) females with a mean age of 54.9 years (± 11.2). Educational attainment among the participants was low, with 142 (25.5%) having had no formal education. Participants spent an average of 33.3 (±13.4) hours per week on the farm, with males spending more time 35.3 (±13.9) than females 29.6 (± 11.8) (p<0.001) and also spent more hours on the farm than females (p<0.001). Participants reported poor distance and near vision, itching/redness, pain and tearing as major complaints. Anterior eye conditions recorded included pterygium 23.7% (CI: 20.3-27.5), allergic conjunctivitis 9.7% (CI: 7.4 - 12.5) and corneal scar/opacity 6.1% (CI: 4.3 - 8.4). Other conditions included cataract 25.5% (CI: 22.0-29.3), glaucoma 15.8 (CI: 12.9 - 19.1) and macular disorders 4.9% (CI: 3.2 - 7.0). Posterior segment conditions and uncorrected refractive errors (67.6%) were the major causes of moderate and severe visual impairment (MSVI) (16.7%) and legal blindness (4.9%) among the population studied. Presbyopia was present in 83.1% (CI: 79.7 - 86.1) of the participants. The rate of ocular injuries was 143/12 854.5 worker years or 11.3/1 000 worker years (95% CI: 9.4 - 31.0), which led to a lost work time injuries of 137 injuries/ 12 854.5 worker years or 37.3/1000 worker years (95% CI: 34.1- 40.8) and were predominantly in males. Blunt injuries from plants/branches and chemical injuries were mostly reported. Only 34 (6.1%) reported using ocular protection. Barriers to use of ocular protection included non availability of the equipment, lack of funds and ignorance or lack of training. More than half of the participants (52.4%) had never seen an eye care practitioner, while 25% reported seeking eye care within the last one year preceding the study. Those who were registered with the National Health Insurance Scheme were more likely to attend a hospital/clinic for eye care services (OR = 3.93, 1.40 - 11.06, p = 0.009). Barriers to utilization of eye facilities included lack of funds, long distance to facility and long waiting time at eye facilities. Two hundred participants enrolled for the quasi-experimented pre-post-tested study, and had varied opinions on ocular health and safety practices on the farm. They demonstrated a good knowledge on the ocular hazards they face at work, although most were unaware of the effect of some of the hazards on the eye. Farmers also had a poor knowledge on ocular protection but a fair knowledge on first aid for ocular emergencies. Participants improved their knowledge scores (overall 40 points) on ocular health and safety practices from a pre- median score of 172 (IQR: 164 - 177.5) to 212 (IQR: 206 - 219.5) following the pre- and postevaluation of the training intervention. Conclusions: Eye disorders are prevalent among cocoa farmers in Ghana. Farmers are engaged in improper ocular health and safety practices on the farm. They also make insufficient use of appropriate protective eye devices and health services. The study demonstrated that, with an ocular health intervention, cocoa farmers can improve on their knowledge and awareness level on ocular health and safety practices which may be of benefit to the farmer, employers and the national economy

Therapeutic approaches to prevent disease recurrence in uveitis

Uveitis is a significant cause of visual morbidity in the working-age population and has a high propensity to recur and cause damage to the ocular tissues which compromise the patient's sight and that can be irreversible. This dissertation addresses the question of how different treatment regimens influence disease recurrence, improve visual outcome and reduce the dose of concomitant immunosuppressive therapy in patients with sight-threatening ocular inflammatory conditions. Therapeutic agents targeting specific inflammatory mediators are playing an increasingly important role in the management of non-infectious uveitis. The first study examined the role of anti-TNFα drugs and rituximab (anti-CD20) in controlling ocular inflammation in 82 patients with non-infectious, intermediate posterior and panuveitis refractory to conventional immunosuppression. Treatment with these agents achieved better disease control manifested by significant reduction in concomitant immunosuppressive therapy, substantial decrease in disease relapse rate and stability in visual acuity. Both adalimumab and infliximab have similar efficacy and corticosteroids sparing effect; however, compared to infliximab, adalimumab was better tolerated and was associated with significantly lower drug discontinuation rate (treatment failure). Behcet's patients on TNFα blockers had 75% risk reduction in disease recurrence compared non-Behcet's disease subjects which point to the central role of TNFα in Behcet disease pathogenesis. Finally, treatment with TNFα inhibitors and rituximab was effective for extended follow-up periods (5 years and beyond). Statins used to reduce serum cholesterol and improve cardiovascular outcomes in high-risk patients was shown to have pleiotropic anti-inflammatory effects in several in-vivo and in vitro studies. The second study is a phase II, randomised, placebo-controlled trial, examined the effect of simvastatin (80 mg per day) on the amount of concomitant immunosuppressive drugs in 32 patients with non-infectious intermediate, posterior, and panuveitis, at one and two years follow-up visits. Analysing the mean prednisolone dose did not show a significant difference between the two groups. Therefore, there is no evidence to support the anti-inflammatory effect of simvastatin in uveitis. However, given the long-term exposure to corticosteroid-based immunosuppressive therapy, these patients were found to have high serum cholesterol. Our data shows that intensive lipid lowering with simvastatin significantly decreased total cholesterol and LDL and thus reducing the risk of atherosclerotic cardiovascular diseases. Ocular toxoplasmosis, the most common cause of infectious posterior uveitis, has drastic consequences on vision if it involves vision-sensitive structures. The third study looked retrospectively at the role of co-trimoxazole as a prophylactic agent in patients with recurrent sight-threatening disease. Prophylaxis course with co-trimoxazole treatment resulted in a substantial reduction in disease recurrence and significant improvement in vision in comparison to controls. To our knowledge, this is the first study to report improvement in visual acuity on prophylactic therapy, in a disease where no therapy, over the past two decades, was reported to achieve an increase in vision