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The United States Preventive Services Task Force as of 2013 states there is insufficient evidence to recommend for or against screening for glaucoma. Therefore, there is no national screening program in the US. Screening, however, is recommended starting at age 40 by the American Academy of Ophthalmology.
There is a glaucoma screening program in the UK. Those at risk are advised to have a dilated eye examination at least once a year.
The diagnosis of BRVO is made clinically by finding retinal hemorrhages in the distribution of an obstructed retinal vein.
- Fluorescein angiography is a helpful adjunct. Findings include delayed venous filling, hypofluorescence caused by hemorrhage and capillary nonperfusion, dilation and tortuosity of veins, leakage due to neovascularization and macular edema.
- Optical coherence tomography is an adjunctive test in BRVO. Macular edema is commonly seen in BRVO in OCT exams. Serial OCT is used as a rapid and noninvasive way of monitoring the macular edema.
Screening for glaucoma is usually performed as part of a standard eye examination performed by optometrists and ophthalmologists. Testing for glaucoma should include measurements of the intraocular pressure via tonometry, anterior chamber angle examination or gonioscopy, and examination of the optic nerve to look for any visible damage to it, or change in the cup-to-disc ratio and also rim appearance and vascular change. A formal visual field test should be performed. The retinal nerve fiber layer can be assessed with imaging techniques such as optical coherence tomography, scanning laser polarimetry, and/or scanning laser ophthalmoscopy (Heidelberg retinal tomogram).
Owing to the sensitivity of all methods of tonometry to corneal thickness, methods such as Goldmann tonometry should be augmented with pachymetry to measure the central corneal thickness (CCT). A thicker-than-average cornea can result in a pressure reading higher than the 'true' pressure whereas a thinner-than-average cornea can produce a pressure reading lower than the 'true' pressure.
Because pressure measurement error can be caused by more than just CCT (i.e., corneal hydration, elastic properties, etc.), it is impossible to 'adjust' pressure measurements based only on CCT measurements. The frequency doubling illusion can also be used to detect glaucoma with the use of a frequency doubling technology perimeter.
Examination for glaucoma also could be assessed with more attention given to sex, race, history of drug use, refraction, inheritance and family history.
Glaucoma has been classified into specific types:
The pressure within the eye is maintained by the balance between the fluid that enters the eye through the ciliary body and the fluid that exits the eye through the trabecular meshwork.
While tonometry, the measuring of IOP and thus a classical instrument in the diagnosis of glaucoma, is not helpful, ophthalmoscopy leads to the diagnosis by showing typical glaucomatous damage, primarily at the optic nerve head, in the absence of elevated IOP. While the excavation of the optic nerve head and the thinning of its rim appear in all kinds of glaucoma (with high tension and with normal tension,in Primary open angle glaucoma (POAG) and in secondary glaucoma), small hemorrhages close to the optic disc have been identified as a characteristic clinical sign of normal tension glaucoma. Visual field is very important to detect NTG. It shows a defect that typically appear deeper, steeper and closer to fixation comparing to patients with POAG.
Since NTG is closely linked to vascular irregularities, a medical check-up by a general practitioner or a specialist in internal medicine is widely recommended in cases of newly diagnosed normal tension glaucoma. An examination that is considered to be of particular importance is a 24-hour monitoring of the blood pressure. NTG patients tend to suffer "dips", sudden and unnoticed drops in blood pressure during sleep.
PEX is usually diagnosed by an eye doctor who examines the eye using a microscope. The method is termed slit lamp examination and it is done with an "85% sensitivity rate and a 100% specificity rate." Since the symptom of increased pressure within the eye is generally painless until the condition becomes rather advanced, it is possible for people afflicted with glaucoma to be in danger yet not be aware of it. As a result, it is recommended that persons have regular eye examinations to have their levels of intraocular pressure measured, so that treatments can be prescribed before there is any serious damage to the optic nerve and subsequent loss of vision.
The development of accurate and reliable non-invasive ICP measurement methods for VIIP has the potential to benefit many patients on earth who need screening and/or diagnostic ICP measurements, including those with hydrocephalus, intracranial hypertension, intracranial hypotension, and patients with cerebrospinal fluid shunts. Current ICP measurement techniques are invasive and require either a lumbar puncture, insertion of a temporary spinal catheter, insertion of a cranial ICP monitor, or insertion of a needle into a shunt reservoir.
Diagnosis is made by an ophthalmologist or optometrist based on the clinical presentation. One indication can be the Amsler sign, which is the presence of blood (hyphema) in the aspirated vitreous fluid, in paracentesis of the anterior chamber. This is caused due to iris atrophy usually seen in FHI and exposure of the fragile iris vasculature to the vitreous fluid. The sudden change of pressure in the anterior chamber upon suction induced by the paracentesis, or during a cataract surgery, causes bursting of the fragile superficial iris capillaries resultsing in micro-bleeding. This is one clinical diagnostic sign of FHI slit lamp examination shows stringy keratic precipitates
Despite the temporary nature of the vision loss, those experiencing amaurosis fugax are usually advised to consult a physician immediately as it is a symptom that may herald serious vascular events, including stroke. Restated, “because of the brief interval between the transient event and a stroke or blindness from temporal arteritis, the workup for transient monocular blindness should be undertaken without delay.” If the patient has no history of giant cell arteritis, the probability of vision preservation is high; however, the chance of a stroke reaches that for a hemispheric TIA. Therefore, investigation of cardiac disease is justified.
A diagnostic evaluation should begin with the patient's history, followed by a physical exam, with particular importance being paid to the ophthalmic examination with regards to signs of ocular ischemia. When investigating amaurosis fugax, an ophthalmologic consult is absolutely warranted if available. Several concomitant laboratory tests should also be ordered to investigate some of the more common, systemic causes listed above, including a complete blood count, erythrocyte sedimentation rate, lipid panel, and blood glucose level. If a particular cause is suspected based on the history and physical, additional relevant labs should be ordered.
If laboratory tests are abnormal, a systemic disease process is likely, and, if the ophthalmologic examination is abnormal, ocular disease is likely. However, in the event that both of these routes of investigation yield normal findings or an inadequate explanation, noninvasive duplex ultrasound studies are recommended to identify carotid artery disease. Most episodes of amaurosis fugax are the result of stenosis of the ipsilateral carotid artery. With that being the case, researchers investigated how best to evaluate these episodes of vision loss, and concluded that for patients ranging from 36–74 years old, "...carotid artery duplex scanning should be performed...as this investigation is more likely to provide useful information than an extensive cardiac screening (ECG, Holter 24-hour monitoring, and precordial echocardiography)." Additionally, concomitant head CT or MRI imaging is also recommended to investigate the presence of a “clinically silent cerebral embolism.”
If the results of the ultrasound and intracranial imaging are normal, “renewed diagnostic efforts may be made,” during which fluorescein angiography is an appropriate consideration. However, carotid angiography is not advisable in the presence of a normal ultrasound and CT.
Imaging studies such as ultrasonography (US), Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) can aid diagnosis. On ultrasound, Coats' disease appears as a hyperechoic mass in the posterior vitreous without posterior acoustic shadowing; vitreous and subretinal hemorrhage may often be observed.
On CT, the globe appears hyperdense compared to normal vitreous due to the proteinaceous exudate, which may obliterate the vitreous space in advanced disease. The anterior margin of the subretinal exudate enhances with contrast. Since the retina is fixed posteriorly at the optic disc, this enhancement has a V-shaped configuration.
On MRI, the subretinal exudate shows high signal intensity on both T1- and T2-weighted images. The exudate may appear heterogeneous if hemorrhage or fibrosis is present. The subretinal space does not enhance with gadolinium contrast. Mild to moderate linear enhancement may be seen between the exudate and the remaining vitreous. The exudate shows a large peak at 1-1.6 ppm on proton MR spectroscopy.
Patients with optic disc drusen should be monitored periodically for ophthalmoscopy, Snellen acuity, contrast sensitivity, color vision, intraocular pressure and threshold visual fields. For those with visual field defects optical coherence tomography has been recommended for follow up of nerve fiber layer thickness. Associated conditions such as angioid streaks and retinitis pigmentosa should be screened for. Both the severity of optic disc drusen and the degree of intraocular pressure elevation have been associated with visual field loss. There is no widely accepted treatment for ODD, although some clinicians will prescribe eye drops designed to decrease the intra-ocular pressure and theoretically relieve mechanical stress on fibers of the optic disc. Rarely choroidal neovascular membranes may develop adjacent to the optic disc threatening bleeding and retinal scarring. Laser treatment or photodynamic therapy or other evolving therapies may prevent this complication.
Without treatment, NTG leads to progressive visual field loss and in the last consequence to blindness. The mainstay of conventional glaucoma therapy, reducing IOP by pressure-lowering eye drops or by surgery, is applied in cases of NTG as well. The rationale: the lower the IOP, the less the risk of ganglion cell loss and thus in the long run of visual function. The appearance of disc hemorrhages is always a warning sign that therapeutic approaches are not successful - the small bleedings, usually described as flame-shaped, almost always indicate a progression of the disease.
Besides this classical glaucoma therapy, the vascular component that exists in the majority of NTG patients has to be managed as well. Dips in blood pressure or a generally low blood pressure have to be prevented - which is a rather uncommon approach in modern medicine where high blood pressure is always seen as an immense clinical challenge, affecting large segments of the population. In patients with systemic hypertension under therapy, the blood pressure should not be lowered too rigorously. NTG might be the only severe (= sight-threatening) disease caused in numerous cases by a too low blood pressure. Both magnesium and low dose calcium channel blockers have been employed in the treatment of some NTG patients. There are therapeutic approaches to underlying conditions like Flammer syndrome. A change in nutrition like the intake of sodium-rich foods has been tried as has the oral administration of low-dosed steroids. Lifestyle interventions are recommended in patients with Flammer syndrome like avoidance of fasting and certain stimuli like a cold environment and stress.
Ocular hypertension is treated with either medications or laser. Medications that lower intraocular pressure work by decreasing aqueous humor production and/or increasing aqueous humor outflow. Laser trabeculoplasty works by increasing outflow. The cannabinoids found in cannabis sativa and indica (marijuana) have been shown to reduce intraocular pressure, by up to 50% for approximately four to five hours. But due to the duration of effect, significant side-effect profile, and lack of research proving efficacy, the American Glaucoma Society issued a position statement in 2009 regarding the use of marijuana as a treatment for glaucoma.
Grossly, retinal detachment and yellowish subretinal exudate containing cholesterol crystals are commonly seen.
Microscopically, the wall of retinal vessels may be thickened in some cases, while in other cases the wall may be thinned with irregular dilatation of the lumen. The subretinal exudate consists of cholesterol crystals, macrophages laden with cholesterol and pigment, erythrocytes, and hemosiderin. A granulomatous reaction, induced by the exudate, may be seen with the retina. Portions of the retina may develop gliosis as a response to injury.
If the diagnostic workup reveals a systemic disease process, directed therapies to treat that underlying cause should be initiated. If the amaurosis fugax is caused by an atherosclerotic lesion, aspirin is indicated, and a carotid endarterectomy considered based on the location and grade of the stenosis. Generally, if the carotid artery is still patent, the greater the stenosis, the greater the indication for endarterectomy. "Amaurosis fugax appears to be a particularly favorable indication for carotid endarterectomy. Left untreated, this event carries a high risk of stroke; after carotid endarterectomy, which has a low operative risk, there is a very low postoperative stroke rate." However, the rate of subsequent stroke after amaurosis is significantly less than after a hemispheric TIA, therefore there remains debate as to the precise indications for which a carotid endarterectomy should be performed. If the full diagnostic workup is completely normal, patient observation is recommended.
Patients usually do not require treatment due to benign nature of the disease. In case cataract develops patients generally do well with cataract surgery.
Macular edema sometimes occurs for a few days or weeks after cataract surgery, but most such cases can be successfully treated with NSAID or cortisone eye drops. Prophylactic use of Nonsteroidal anti-inflammatory drugs has been reported to reduce the risk of macular edema to some extent.
In 2010 the US FDA approved the use of Lucentis intravitreal injections for macular edema.
Iluvien, a sustained release intravitreal implant developed by Alimera Sciences, has been approved in Austria, Portugal and the U.K. for the treatment of vision impairment associated with chronic diabetic macular edema (DME) considered insufficiently responsive to available therapies. Additional EU country approvals are anticipated.
In 2013 Lucentis by intravitreal injection was approved by the National Institute for Health and Care Excellence in the UK for the treatment of macular edema caused by diabetes and/or retinal vein occlusion.
On July 29, 2014, Eylea (aflibercept), an intravitreal injection produced by Regeneron Pharmaceuticals Inc., was approved to treat DME in the United States.
The diagnosis is clinical. The intraocular pressure (IOP) can be measured in the office in a conscious swaddled infant using a Tonopen or hand-held Goldmann tonometer. Usually, the IOP in normal infants is in the range of 11-14 mmHg. Buphthalmos and Haab's striae can often be seen in case of congenital glaucoma.
In general, BRVO has a good prognosis: after 1 year 50–60% of eyes have been reported to have a final VA of 20/40 or better even without any treatment. With time the dramatic picture of an acute BRVO becomes more subtle, hemorrhages fade so that the retina can look almost normal. Collateral vessels develop to help drain the affected area.
If caught early, the neovascularization can be reversed with prompt pan retinal photocoagulation (PRP), or injection of anti-VEGF medications with subsequent PRP. The injection blocks the direct effect of VEGF and acts more quickly but will wear off in about 6 weeks. PRP has a slower onset of action but can last permanently. Once the neovascularization has been longstanding, the new vessels recruit fibrous tissue, and as this forms and contracts, the angle can be permanently damaged, and will not respond to treatment. If this occurs, then surgical intervention is required to reduce the pressure (such as a glaucoma drainage implant)
In 2005, steroids were investigated for the treatment of macular edema due to retinal blood vessel blockage such as CRVO and BRVO.
Intraocular pressure should be measured as part of the routine eye examination.
It is usually only elevated by iridocyclitis or acute-closure glaucoma, but not by relatively benign conditions.
In iritis and traumatic perforating ocular injuries, the intraocular pressure is usually low.
Checking the eyes for signs of papilledema should be carried out whenever there is a clinical suspicion of raised intracranial pressure, and is recommended in newly onset headaches. This may be done by ophthalmoscopy or fundus photography, and possibly slit lamp examination.
There are different approaches to non-invasive intracranial pressure measurement, which include ultrasound "time-of-flight" techniques, transcranial Doppler, methods based on acoustic properties of the cranial bones, EEG, MRI, tympanic membrane displacement, oto-acoustic emission, ophthalmodynamometry, ultrasound measurements of optic nerve sheath diameter, and Two-Depth Transorbital Doppler. Most of the approaches are "correlation based". Such approaches can not measure an absolute ICP value in mmHg or other pressure units because of the need for individual patient specific calibration. Calibration needs non-invasive "gold standard" ICP meter which does not exists.
Non-invasive absolute intracranial pressure value meter, based on ultrasonic Two-Depth Transorbital Doppler technology, has been shown to be accurate and precise in clinical settings and prospective clinical studies. Analysis of the 171 simultaneous paired recordings of non-invasive ICP and the "gold standard" invasive CSF pressure on 110 neurological patients and TBI patients showed good accuracy for the non-invasive method as indicated by the low mean systematic error (0.12 mmHg; confidence level (CL) = 0.98). The method also showed high precision as indicated by the low standard deviation (SD) of the random errors
(SD = 2.19 mmHg; CL = 0.98).
This measurement method and technique (the only non-invasive ICP measurement technique which already received EU CE Mark approval) eliminates the main limiting problem of all other non-successful "correlation based" approaches to non-invasive ICP absolute value measurement - the need of calibration to the individual patient.
In most patients, optic disc drusen are an incidental finding. It is important to differentiate them from other conditions that present with optic disc elevation, especially papilledema, which could imply raised intracranial pressure or tumors. True papilledema may present with exudates or cotton-wool spots, unlike ODD. The optic disc margins are characteristically irregular in ODD but not blurred as there is no swelling of the retinal nerve fibers. Spontaneous venous pulsations are present in about 80 percent of patients with ODD, but absent in cases of true disc edema. Other causes of disc elevation clinicians must exclude may be: hyaloid traction, epipapillary glial tissue, myelinated nerve fibres, scleral infiltration, vitreopapillary traction and high hyperopia. Disorders associated with disc elevation include: Alagille syndrome, Down syndrome, Kenny-Caffey syndrome, Leber Hereditary Optic Neuropathy and linear nevus sebaceous syndrome.