Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
A meta-analysis found evidence that does not support the use of patching.
Topical antibiotics may be reasonable.
One review has found that eye drops to numb the surface of the eye such as tetracaine improve pain; however, their safety is unclear. Another review did not find evidence of benefit and concluded there was not enough data on safety.
NSAID eye drops are also useful. A 2000 review found no good evidence to support medications that paralyze the iris. A 2017 review did not find evidence to suggest that topical NSAIDs would significantly reduce pain over standard-of-care treatments, but did find that NSAIDs could be associated with people using fewer pain medications by mouth.
Given that episodes tend to occur on awakening and managed by use of good 'wetting agents', approaches to be taken to help prevent episodes include:
- Environmental:
- ensuring that the air is humidified rather than dry, not overheated and without excessive airflow over the face. Also avoiding irritants such as cigarette smoke.
- use of protective glasses especially when gardening or playing with children.
- General personal measures:
- maintaining general hydration levels with adequate fluid intake.
- not sleeping-in late as the cornea tends to dry out the longer the eyelids are closed.
- Pre-bed routine:
- routine use of long-lasting eye ointments applied before going to bed.
- occasional use of the anti-inflammatory eyedrop FML (prescribed by an ophthalmologist or optometrist) before going to bed if the affected eye feels inflamed, dry or gritty
- use of a hyperosmotic (hypertonic) ointment before bed reduces the amount of water in the epithelium, strengthening its structure
- use the pressure patch as mentioned above.
- use surgical tape to keep the eye closed (if Nocturnal Lagophthalmos is a factor)
- Waking options:
- learn to wake with eyes closed and still and keeping artificial tear drops within reach so that they may be squirted under the inner corner of the eyelids if the eyes feel uncomfortable upon waking.
- It has also been suggested that the eyelids should be rubbed gently, or pulled slowly open with your fingers, before trying to open them, or keeping the affected eye closed while "looking" left and right to help spread lubricating tears. If the patient's eyelids feel stuck to the cornea on waking and no intense pain is present, use a fingertip to press firmly on the eyelid to push the eye's natural lubricants onto the affected area. This procedure frees the eyelid from the cornea and prevents tearing of the cornea.
With the eye generally profusely watering, the type of tears being produced have little adhesive property. Water or saline eye drops tend therefore to be ineffective. Rather a 'better quality' of tear is required with higher 'wetting ability' (i.e. greater amount of glycoproteins) and so artificial tears (e.g. viscotears) are applied frequently. Also recommended is Muro 128 5% Ointment (Sodium Chloride Hypertonicity Ophthalmic Ointment, 5%) which is a great relief overnight, it lasts longer than most regular tears and provides protection for those with severe cases.
Nocturnal Lagophthalmos (where one’s eyelids don’t close enough to cover the eye completely during sleep) may be an exacerbating factor, in which case using surgical tape to keep the eye closed at night can help.
Whilst individual episodes may settle within a few hours or days, additional episodes (as the name suggests) will recur at intervals.
Where episodes frequently occur, or there is an underlying disorder, one medical, or three types of surgical curative procedures may be attempted:
use of therapeutic contact lens, controlled puncturing of the surface layer of the eye (Anterior Stromal Puncture) and laser phototherapeutic keratectomy (PTK). These all essentially try to allow the surface epithelium to reestablish with normal binding to the underlying basement membrane, the method chosen depends upon the location & size of the erosion.
Proper diagnosis is essential for optimal treatment. Bacterial corneal ulcer require intensive fortified antibiotic therapy to treat the infection. Fungal corneal ulcers require intensive application of topical anti-fungal agents. Viral corneal ulceration caused by herpes virus may respond to antivirals like topical acyclovir ointment instilled at least five times a day. Alongside, supportive therapy like pain medications are given, including topical cycloplegics like atropine or homatropine to dilate the pupil and thereby stop spasms of the ciliary muscle. Superficial ulcers may heal in less than a week. Deep ulcers and descemetoceles may require conjunctival grafts or conjunctival flaps, soft contact lenses, or corneal transplant. Proper nutrition, including protein intake and Vitamin C are usually advised. In cases of Keratomalacia, where the corneal ulceration is due to a deficiency of Vitamin A, supplementation of the Vitamin A by oral or intramuscular route is given. Drugs that are usually contraindicated in corneal ulcer are topical corticosteroids and anesthetics - these should not be used on any type of corneal ulcer because they prevent healing, may lead to superinfection with fungi and other bacteria and will often make the condition much worse.
Topical antibiotics are used at hourly intervals to treat infectious corneal ulcers. Cycloplegic eye drops are applied to give rest to the eye. Pain medications are given as needed. Loose epithelium and ulcer base can be scraped off and sent for culture sensitivity studies to find out the pathogenic organism. This helps in choosing appropriate antibiotics. Complete healing takes anywhere from about a few weeks to several months.
Refractory corneal ulcers can take a long time to heal, sometimes months. In case of progressive or non-healing ulcers, surgical intervention by an ophthalmologist with corneal transplantation may be required to save the eye. In all corneal ulcers it is important to rule out predisposing factors like diabetes mellitus and immunodeficiency.
The treatment of corneal perforation depends on the location, severity and the cause of damage
- Tissue adhesive can be used to seal small perforation, but this method cannot be used to treat perforations larger than 1 mm.
- Non infected corneal perforation generally heals when a pressure bandage is used.
- For certain types of corneal perforations, lamellar keratoplasty is used as treatment.
Early diagnosis, targeted treatment according to the severity of the disease, and regular monitoring of patients with neurotrophic keratitis are critical to prevent damage progression and the occurrence of corneal ulcers, especially considering that the deterioration of the condition is often poorly symptomatic.
The purpose of treatment is to prevent the progression of corneal damage and promote healing of the corneal epithelium. The treatment should always be personalized according to the severity of the disease. Conservative treatment is typically the best option.
In stage I, the least serious, treatment consists of the administration of preservative-free artificial tears several times a day in order to lubricate and protect the ocular surface, improving the quality of the epithelium and preventing the possible loss of transparency of the cornea.
In stage II, treatment should be aimed at preventing the development of corneal ulcers and promoting the healing of epithelial lesions. In addition to artificial tears, topical antibiotics may also be prescribed to prevent possible infections. Patients should be monitored very carefully since, being the disease poorly symptomatic, the corneal damage may progress without the patient noticing any worsening of the symptoms. Corneal contact lenses can also be used in this stage of the disease, for their protective action to improve corneal healing.
In the most severe forms (stage III), it is necessary to stop the progression towards corneal perforation: in these cases, a possible surgical treatment option is tarsorrhaphy, i.e. the temporary or permanent closure of the eyelids by means of sutures or botulinum toxin injection. This protects the cornea, although the aesthetic result of these procedures may be difficult to accept for patients. Similarly, a procedure that entails the creation of a conjunctival flap has been shown to be effective in the treatment of chronic corneal ulcers with or without corneal perforation. In addition, another viable therapeutic option is amniotic membrane graft, which has recently been shown to play a role in stimulating corneal epithelium healing and in reducing vascularisation and inflammation of the ocular surface . Other approaches used in severe forms include the administration of autologous serum eye drops.
Research studies have focused on developing novel treatments for neurotrophic keratitis, and several polypeptides, growth factors and neuromediators have been proposed[25]. Studies were conducted on topical treatment with Substance P and IGF-1 (insulin-like growth factor-1), demonstrating an effect on epithelial healing[26]. Nerve Growth Factor (NGF) play a role in the epithelial proliferation and differentiation and in the survival of corneal sensory nerves. Topical treatment with murine NGF showed to promote recovery of epithelial integrity and corneal sensitivity in NK patients[27]. Recently, a recombinant human nerve growth factor eye drop formulation has been developed for clinical use[28].
Cenegermin, a recombinant form of human NGF, has recently been approved in Europe in an eye drop formulation for neurotrophic keratitis.
The effect is normally temporary and after a period of six to eight weeks, the cornea usually returns to its former transparency. The recovery can be aided nonsurgically by bandaging with an osmotic saline solution. Non-steroidal anti-inflammatory topical may be used to reduce the pain and inflammation.
The goal of investigation is the assessment of the severity of the ocular injury with an eye to implementing a management plan as soon as is required. The usual eye examination should be attempted, and may require a topical anesthetic in order to be tolerable. Many topical agents cause burning upon instillation. Proxymetacaine has been found to have the best tolerance.
Depending on the medical history and preliminary examination, the primary care physician should designate the eye injury as a "true emergency", "urgent" or "semi-urgent".
Multiple complications are known to occur following eye injury: corneal scarring, hyphema, iridodialysis, post-traumatic glaucoma, uveitis cataract, vitreous hemorrhage and retinal detachment. The complications risk is high with retinal tears, penetrating injuries and severe blunt trauma.
Treatments for corneal neovascularization are predominately off-lab with a multitude of complications as a result. The desired results from medical therapy may not always occur, ergo an invasive procedure may be needed to prevent further decrease in corneal avascularity.
For contact lenses related hypoxia, ceasing the use of contact lenses is the first step until corneal neovascularization is addressed by a physician. Modern rigid gas permeable and silicon hydrogel contact lenses have a much higher level of oxygen transmissibility, making them effective alternatives to help prevent corneal neovascularization.
Topical administration of steroids and non-steroid anti-inflammatory drugs are first-line treatment for individuals with CNV. The administration of steroids can increase the risk of infection, glaucoma, cataracts, herpes simplex recurrence. The anti-inflammatory drugs, however, increase the risk of corneal ulceration and melting.
Since VEGF plays an important role in vasculogenesis and pathologic neovascularization associated with eye diseases, a potential treatment for CNV is to inhibit VEGF activity by competing the binding of VEGF with specific neutralizing anti-VEGF antibody. VEGF inhibitors include pegatanib sodium, ranibizumab, and off-label bevacizumab are currently used for treatment of various retinal disease. Anti-VEGF antibodies such as the application of ranibizumab or bevacizumab have has been shown to reduce corneal neovascularization. Both ranibizumab and bevacizumab uses the same mechanism and inhibits all iso-forms of VEGF. The significant reduction in invasion of in-growth blood vessels in terms of neovascular area and vessel caliber suggests that treatment with ranibizumab induces thinning of the blood vessels, however, there's no significant change of the blood vessel's length. Using anti-VEGF antibodies to treat CNV has some limitations such as it is not a cure and may require repeated treatments to maintain positive effects over time. Topical and/or subconjunctival administration of bevaicizumab or ranibizumab have demonstrated short-term safety and efficacy, however long term effects have not been documented. Anti-VEGF therapy is currently an experimental treatment.
If the cornea is inflamed via corneal neovascularization, the suppression of enzymes can block CNV by compromising with corneal structural integrity. Corneal neovascularization can be suppressed with a combination of orally administration of doxycycline and with topical corticosteroid.
Surgical Options
Invasive solutions for corneal neovascularization are reserved when the medical therapies do not provide the desired results.
Invading blood tissues and ablating tissues in the cornea can be obstructed by the use of laser treatments such as Argon and s. Irradiation and/or damages to adjacent tissues caused by the procedure can result in corneal hemorrhage and corneal thinning. Obstruction of the blood vessels can be unsuccessful due to the depth, size, and, high blood flow rate of the vessels. In conjunction, thermal damage from the lasers can trigger inflammatory response which can exaggerate the neovascularization.
An effective treatment is photodynamic therapy, however, this treatment has limited clinical acceptance due to high costs and many potential complications involved that are also related to laser ablation. Complications can include irradiation from previously injected photosensitive dye inducing apoptosis and necrosis of the endothelium and basement membrane.
Diathermy and cautery is a treatment where an electrolysis needle is inserted into the feeder vessels in the limbus. The vessels are obstructed by a coagulating current through the use of unipolar diathermy unit or by thermal cautery.
Treatment options include contact lenses, intrastromal corneal ring segments, corneal collagen cross-linking, or corneal transplant.
When cross-linking is performed only after the cornea becomes distorted, vision remains blurry even though the disease is stabilised. As a result, combining corneal collagen cross-linking with LASIK ('LASIK Xtra') aims to strengthen the cornea at the point of surgery and may be useful in cases where a very thin cornea is expected after the LASIK procedure. This would include cases of high spectacle power and people with thin corneas before surgery. Definitive evidence that the procedure can reduce the risk of corneal ectasia will only become available a number of years later as corneal ectasia, if it happens, usually occurs in the late post-operative period. Some study show that combining LASIK with cross-linking adds refractive stability to hyperopic treatments and may also do the same for very high myopic treatments.
In 2016, the FDA approved the KXL system and two photoenhancers for the treatment of corneal ectasia following refractive surgery.
Some of the adverse outcomes associated with intra-operative injuries include:
- Increased length of stay. This is due to ophthalmology consults required, associated infections and treatment.
- Increased costs. This is due to increased length of stay, cost of treating the complications.
- Pain and discomfort for the patient. Corneal abrasions are extremely painful for the patient and the treatment consists of drops and ointments applied in the eye which may cause further discomfort for the patient.
Reduction of neovascularization has been achieved in rats by the topical instillation of commercially available triamcinolone and doxycycline.
Some evidence exists to suggest that the Angiotensin II receptor blocker drug telmisartan will prevent corneal neovascularization.
Recent treatment developments include topical application of bevacizumab, an anti-VEGF.
Previous long-standing eye infection which possibly during childhood time recalled as being treated with antibiotic and/or hospitalized over long period of time.
The underlying cause must be treated as soon as possible to stop the disease process. Corticosteroid drop can be used to minimize the scarring on the cornea along with antibiotic cover. However, residual scarring cannot be avoided which can result in long term visual impairment and corneal transplantation is not suitable due to high rejection rate from the corneal vascularization.
Corneal perforation is an anomaly in the cornea resulting from damage to the corneal surface. A corneal perforation means that the cornea has been penetrated, thus leaving the cornea damaged.
The cornea is a clear part of the eye which controls and focuses the entry of light into the eye. Damage to the cornea due to corneal perforation can cause decreased visual acuity.
Corneal hydrops might be caused by a tear in the recently discovered Dua's layer, a 15 micron thick layer between the corneal stroma and Descemet’s membrane, Harminder Dua suggests that this finding will affect corneal surgery, including penetrating keratoplasty, and understanding of corneal dystrophies and pathologies, such as acute hydrops.
Neurotrophic keratitis (NK) is a degenerative disease of the cornea caused by damage of the trigeminal nerve, which results in impairment of corneal sensitivity, spontaneous corneal epithelium breakdown, poor corneal healing and development of corneal ulceration, melting and perforation.
Neurotrophic keratitis is classified as a rare disease, with an estimated prevalence of less than 5 in 10,000 people in Europe. It has been recorded that on average, 6% of herpetic keratitis cases may evolve to this disease, with a peak of 12.8% of cases of keratitis due to herpes zoster virus.
The diagnosis, and particularly the treatment of neurotrophic keratitis are the most complex and challenging aspects of this disease, as a satisfactory therapeutic approach is not yet available.
Prophylaxis consists of periodic administration of Vitamin A supplements. WHO recommended schedule, which is universally recommended is as follows:
- Infants 6–12 months old and any older children weighing less than 8 kg - 100,000 IU orally every 3–6 months
- Children over 1 year and under 6 years of age - 200,000 IU orally every 6 months
- Infants less than 6 months old, who are not being breastfed - 50,000 IU orally should be given before they attain the age of 6 months
The most commonly employed method is to use tape or a general purpose adhesive dressing. Unfortunately the adhesive used on the tape or dressing will generally be inappropriate for this use. The adhesive strength may change when reaching body temperature, or over time.
As the operation progresses this can cause the adhesive to stop working and become gooey, allowing the eyelids to move apart, and leaving behind a sticky residue. This leaves the cornea exposed to epithelial drying and/or abrasions, sometimes caused by the tape that was originally applied to protect the cornea. Alternatively, the adhesive strength may increase, which upon removal can result in eyelid bruising, tears, or eyelash removal.
Rolls of tapes are often “laying around” the operating theatre or kept in health care workers' pockets.
Therefore, they can be a source of hospital-acquired infections (HAI's) such as Methicillin-resistant Staphylococcus aureus (MRSA) & Vancomycin-resistant Enterococcus (VRE), with a 2010 study showing that 50% of partially used tape rolls tested positive for MRSA, VRE or both.
Most tapes and dressings are non-transparent and so it is not possible to see if the patient’s eyes are opened or closed throughout the case. It is not uncommon for the eyelids to move open as the case progresses, even with adhesive tapes stuck onto them. In a practical sense, these medical tapes/dressings may be difficult to remove from a patient because their ends can become stuck flush with the skin. The possibility of tape removal causing trauma is also significantly increased in older people, people with sensitive skin, dermatitis, dehydration or side effects of medications.
As noted above, there have been several studies looking at the efficacy and safety of eye ointments/lubricants as adjuncts with tape or as a stand-alone management for intra-operative eye closure. Unfortunately many in common use have problems. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservative-free eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia.
They have been implicated in blurred vision in up to 75% of patients and they do not protect from direct trauma.
Specially made eyelid occlusion dressings are available commercially, such as EyeGard (manufactured in the USA by KMI Surgical and marketed by Sharn Anesthesia), EyePro (Andsco Medical Pty Ltd, Australia) and Anesthesia-Aid (Sperian Protection). These dressings overcome most of the problems associated with tape or general purpose dressings.
A red eye is an eye that appears red due to illness or injury. It is usually injection and prominence of the superficial blood vessels of the conjunctiva, or sclera, which may be caused by disorders of these or adjacent structures. Conjunctivitis and subconjunctival hemorrhage are two of the less serious but more common causes.
Management includes assessing whether emergency action (including referral) is needed, or whether treatment can be accomplished without additional resources.
Slit lamp examination is invaluable in diagnosis but initial assessment can be performed using a careful history, testing vision (visual acuity), and carrying out a penlight examination.
Treatment can occur in two ways: treating symptoms and treating the deficiency. Treatment of symptoms usually includes the use of artificial tears in the form of eye drops, increasing the humidity of the environment with humidifiers, and wearing wraparound glasses when outdoors. Treatment of the deficiency can be accomplished with a Vitamin A or multivitamin supplement or by eating foods rich in Vitamin A. Treatment with supplements and/or diet can be successful until the disease progresses as far as corneal ulceration, at which point only an extreme surgery can offer a chance of returning sight.
Before LASIK surgery, people must be examined for possible risk factors such as keratoconus.
Abnormal corneal topography compromises of keratoconus, pellucid marginal degeneration, or forme fruste keratoconus with an I-S value of 1.4 or more is the most significant risk factor. Low age, low residual stromal bed (RSB) thickness, low preoperative corneal thickness, and high myopia are other important risk factors.