Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described as the optical analogue to ultrasound. The inherent safety of the technology allows for in vivo use of OCT in patients. The main strength of OCT is the depth resolution. In dermatology, most OCT research has turned on non-melanoma skin cancer (NMSC) and non-invasive monitoring of morphological changes in a number of skin diseases based on pattern recognition, and studies have found good agreement between OCT images and histopathological architecture. OCT has shown high accuracy in distinguishing lesions from normal skin, which is of great importance in identifying tumour borders or residual neoplastic tissue after therapy. The OCT images provide an advantageous combination of resolution and penetration depth, but specific studies of diagnostic sensitivity and specificity in dermatology are sparse. In order to improve OCT image quality and expand the potential of OCT, technical developments are necessary. It is suggested that the technology will be of particular interest to the routine follow-up of patients undergoing non-invasive therapy of malignant or premalignant keratinocyte tumours. It is speculated that the continued technological development can propel the method to a greater level of dermatological use.

https://link.springer.com/content/pdf/bfm%3A978-3-319-06419-2%2F1.pdf

Optical Coherence Tomography

2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides J. Jennette;R. Falk;P. Bacon;N. Basu;M. Cid;F. Ferrario;L. Flores-Suarez;W. Gross;L. Guillevin;E. Hagen;G. Hoffman;D. Jayne;C. Kallenberg;P. Lamprecht;C. Langford;R. Luqmani;A. Mahr;E. Matteson;P. Merkel;S. Ozen;C. Pusey;N. Rasmussen;A. Rees;D. Scott;U. Specks;J. Stone;K. Takahashi;R. Watts; Arthritis & Rheumatism

https://onlinelibrary.wiley.com/doi/epdf/10.1002/art.37715

2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides

Background Retinal ischemia induces intraocular neovascularization, which often leads to glaucoma, vitreous hemorrhage, and retinal detachment, presumably by stimulating the release of angiogenic molecules. Vascular endothelial growth factor (VEGF) is an endothelial-cell-specific angiogenic factor whose production is increased by hypoxia. Methods We measured the concentration of VEGF in 210 specimens of ocular fluid obtained from 164 patients undergoing intraocular surgery, using both radioimmunoassays and radioreceptor assays. Vitreous proliferative potential was measured with in vitro assays of the growth of retinal endothelial cells and with VEGF-neutralizing antibody. Results VEGF was detected in 69 of 136 ocular-fluid samples from patients with diabetic retinopathy, 29 of 38 samples from patients with neovascularization of the iris, and 3 of 4 samples from patients with ischemic occlusion of the central retinal vein, as compared with 2 of 31 samples from patients with no neovascular disorders (P<0.00...

https://www.nejm.org/doi/pdf/10.1056/NEJM199412013312203

Vascular Endothelial Growth Factor in Ocular Fluid of Patients with Diabetic Retinopathy and Other Retinal Disorders

OBJECTIVE To examine the global prevalence and major risk factors for diabetic retinopathy (DR) and vision-threatening diabetic retinopathy (VTDR) among people with diabetes. RESEARCH DESIGN AND METHODS A pooled analysis using individual participant data from population-based studies around the world was performed. A systematic literature review was conducted to identify all population-based studies in general populations or individuals with diabetes who had ascertained DR from retinal photographs. Studies provided data for DR end points, including any DR, proliferative DR, diabetic macular edema, and VTDR, and also major systemic risk factors. Pooled prevalence estimates were directly age-standardized to the 2010 World Diabetes Population aged 20–79 years. RESULTS A total of 35 studies (1980–2008) provided data from 22,896 individuals with diabetes. The overall prevalence was 34.6% (95% CI 34.5–34.8) for any DR, 6.96% (6.87–7.04) for proliferative DR, 6.81% (6.74–6.89) for diabetic macular edema, and 10.2% (10.1–10.3) for VTDR. All DR prevalence end points increased with diabetes duration, hemoglobin A 1c , and blood pressure levels and were higher in people with type 1 compared with type 2 diabetes. CONCLUSIONS There are approximately 93 million people with DR, 17 million with proliferative DR, 21 million with diabetic macular edema, and 28 million with VTDR worldwide. Longer diabetes duration and poorer glycemic and blood pressure control are strongly associated with DR. These data highlight the substantial worldwide public health burden of DR and the importance of modifiable risk factors in its occurrence. This study is limited by data pooled from studies at different time points, with different methodologies and population characteristics.

/pdf/global-prevalence-and-major-risk-factors-of-diabetic-gaynvrvnk8.pdf

Global Prevalence and Major Risk Factors of Diabetic Retinopathy

Jennette JC, Falk RJ, Bacon PA, Basu N, Cid MC, Ferrario F, Flores-Suarez LF, Gross WL, Guillevin L, Hagen EC, Hoffman GS, Jayne DR, Kallenberg CGM, Lamprecht P, Langford CA, Luqmani RA, Mahr AD, Matteson EL, Merkel PA, Ozen S, Pusey CD, Rasmussen N, Rees AJ, Scott DGI, Specks U, Stone JH, Takahashi K, Watts RA. Running Head:

2012 Revised International Chapel Hill Consensus Conference Nomenclature of

Nocturnal arterial hypotension and its role in optic nerve head and ocular ischemic disorders.

The blood supply of the optic disc is an important and a fascinating subject in ophthalmology. Since the time of Haller (I754) and Zinn (I755) it has remained the centre of controversy. The literature on the subject has recently been reviewed in detail by Hayreh (i963a), Fransois and Neetens (I966), and Bonamour, Bregeat, Bonnet, and Juge (I968). The recent introduction of fluorescence angiography has made a significant contribution to the subject because it enables us to study the microcirculation in vivo.

/pdf/blood-supply-of-the-optic-nerve-head-and-its-role-in-optic-2to030ukmx.pdf

Blood supply of the optic nerve head and its role in optic atrophy, glaucoma, and oedema of the optic disc.

Ocular manifestations of giant cell arteritis.

Though anterior ischemic optic neuropathy (AION) has been widely reported, it is not fully appreciated as one of the commonest causes of impaired vision in persons past middle age. These patients are not infrequently suspected of having an intracranial tumor. This article reviews the clinical features of AION and discusses its pathogenesis and treatment.

Anterior Ischemic Optic Neuropathy

The data from 159 patients (217 eyes) with episscleritis and 207 patients (301 eyes) with scleritis have been investigated in detail and the results analysed with the help of a computer. Of these patients, 91 per cent were followed-up during a period of one to eight years. A new classification is presented which is as follows: Episcleritis (217 eyes) Simple episcleritis (170 eyes) Nodular episcleritis (47 eyes) Scleritis (301 eyes) Diffuse anterior scleritis (119 eyes) Nodular anterior scleritis (134 eyes) Necrotizing scleritis (42 eyes). Of these, 13 were regarded as scleromalacia perforans. Posterior scleritis (6 eyes) The diagnosis is based on an exact clinical examination which is fully described. Episcleritis has been shown to be a benign recurring condition, a mild keratitis being the only occasional complication. Episcleritis does not progress to scleritis, except in the case of herpes zoster which sometimes starts as an episcleritis with the vesicular stage of the eruption, to reappear three months later as a scleritis in the same site. No clear conclusions could be drawn as to the aetiology of episcleritis.

https://bjo.bmj.com/content/bjophthalmol/60/3/163.full.pdf

Sohan Singh Hayreh

Papers

Nocturnal arterial hypotension and its role in optic nerve head and ocular ischemic disorders.

Blood supply of the optic nerve head and its role in optic atrophy, glaucoma, and oedema of the optic disc.

Ocular manifestations of giant cell arteritis.

Anterior Ischemic Optic Neuropathy

Scleritis and episcleritis.