The patient has red eye and a working diagnosis of scleritis, which requires a same day specialist assessment. Features of serious causes of red eye include moderate to severe eye pain or photophobia, marked redness of one eye, and reduced visual acuity. Oral cetirizine may be useful in allergic conjunctivitis, while chloramphenicol drops are used in severe infective conjunctivitis. Fusidic acid drops are an alternative treatment option for infective conjunctivitis. Episcleritis is a possible differential diagnosis but is unlikely due to the patient’s severe pain.

Understanding the Causes of Red Eye

Red eye is a common condition that can be caused by various factors. It is important to identify the underlying cause of red eye to determine the appropriate treatment. Some causes of red eye require urgent referral to an ophthalmologist. Here are some key distinguishing features of different causes of red eye:

Acute angle closure glaucoma is characterized by severe pain, decreased visual acuity, and a semi-dilated pupil. The patient may also see haloes and have a hazy cornea.

Anterior uveitis has an acute onset and is accompanied by pain, blurred vision, and photophobia. The pupil is small and fixed, and there may be ciliary flush.

Scleritis is characterized by severe pain and tenderness, which may be worse on movement. It may be associated with an underlying autoimmune disease such as rheumatoid arthritis.

Conjunctivitis may be bacterial or viral. Bacterial conjunctivitis is characterized by purulent discharge, while viral conjunctivitis has a clear discharge.

Subconjunctival haemorrhage may be caused by trauma or coughing bouts.

Endophthalmitis typically occurs after intraocular surgery and is characterized by a red eye, pain, and visual loss.

By understanding the different causes of red eye and their distinguishing features, healthcare professionals can provide appropriate treatment and referral when necessary.

Differentiating Conjunctivitis: Causes and Symptoms

Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and the inner surface of the eyelids. It can be caused by various factors, including bacteria, viruses, allergens, and sexually transmitted infections. Here are some of the different types of conjunctivitis and their distinguishing features:

Chlamydial Conjunctivitis: This type of conjunctivitis is transmitted through autoinoculation or eye-to-eye spread and is associated with urethritis or cervicitis. It is caused by Chlamydia trachomatis and can last for up to 12 months if left untreated. It is usually unilateral and presents with chronic follicular conjunctivitis.

Trachoma: This type of conjunctivitis is caused by poor sanitation and is the third most common cause of blindness in the world. It is caused by serotypes A to C of C. trachomatis and presents with severe conjunctival scarring and secondary corneal ulceration and scarring.

Allergic Conjunctivitis: This type of conjunctivitis occurs in atopic individuals and presents with itchy, watering eyes.

Gonococcal Conjunctivitis: This type of conjunctivitis is caused by gonorrhea and presents with a rapid onset of unilateral/bilateral red eyes with a severe purulent discharge and tender preauricular lymph nodes.

Simple Bacterial Conjunctivitis: This type of conjunctivitis is usually bilateral and should have resolved by three weeks. The discharge is mucopurulent but less copious than in gonococcal conjunctivitis.

Viral Conjunctivitis: This type of conjunctivitis is usually bilateral and should have resolved by three weeks. The discharge is usually watery, and follicles may be seen on eyelid eversion.

In summary, the type of conjunctivitis can be determined by the symptoms and the underlying cause. It is important to seek medical attention if symptoms persist or worsen.

The main impact of glaucoma is on the patient’s visual field, as it causes an optic neuropathy. This typically starts with peripheral vision loss and can progress to tunnel vision if left untreated. While visual acuity may also be affected, it is not as commonly impacted as the visual field.

Glaucoma is a condition where the optic nerve is damaged due to increased intraocular pressure (IOP). Primary open-angle glaucoma (POAG) is a type of glaucoma where the peripheral iris doesn’t cover the trabecular meshwork, which is responsible for draining aqueous humour from the eye. POAG is more common in older individuals, with up to 10% of those over 80 years of age affected. Genetics, Afro-Caribbean ethnicity, myopia, hypertension, diabetes mellitus, and corticosteroid use are all risk factors for POAG. POAG may present with peripheral visual field loss, decreased visual acuity, and optic disc cupping, which can be detected during routine optometry appointments.

Fundoscopy signs of POAG include optic disc cupping, optic disc pallor, bayonetting of vessels, and cup notching. Optic disc cupping occurs when the cup-to-disc ratio is greater than 0.7, indicating a loss of disc substance. Optic disc pallor indicates optic atrophy, while bayonetting of vessels occurs when vessels have breaks as they disappear into the deep cup and reappear at the base. Cup notching usually occurs inferiorly where vessels enter the disc, and disc haemorrhages may also be present.

The diagnosis of POAG is made through a series of investigations, including automated perimetry to assess visual field, slit lamp examination with pupil dilatation to assess optic nerve and fundus for a baseline, applanation tonometry to measure IOP, central corneal thickness measurement, and gonioscopy to assess peripheral anterior chamber configuration and depth. The risk of future visual impairment is assessed using risk factors such as IOP, central corneal thickness (CCT), family history, and life expectancy. If POAG is suspected, referral to an ophthalmologist is necessary for further evaluation and management.

Yellow-green vision may be a side effect of digoxin.

The use of digoxin carries a significant risk of toxicity due to its limited therapeutic range. One of the symptoms of toxicity is the appearance of yellow-tinted vision, also known as xanthopsia.

Similarly, sildenafil use may result in cyanopsia or blue-tinted vision.

Understanding Digoxin and Its Toxicity

Digoxin is a medication used for rate control in atrial fibrillation and for improving symptoms in heart failure patients. It works by decreasing conduction through the atrioventricular node and increasing the force of cardiac muscle contraction. However, it has a narrow therapeutic index and can cause toxicity even when the concentration is within the therapeutic range.

Toxicity may present with symptoms such as lethargy, nausea, vomiting, confusion, and yellow-green vision. Arrhythmias and gynaecomastia may also occur. Hypokalaemia is a classic precipitating factor as it increases the inhibitory effects of digoxin. Other factors include increasing age, renal failure, myocardial ischaemia, and various electrolyte imbalances. Certain drugs, such as amiodarone and verapamil, can also contribute to toxicity.

If toxicity is suspected, digoxin concentrations should be measured within 8 to 12 hours of the last dose. However, plasma concentration alone doesn’t determine toxicity. Management includes the use of Digibind, correcting arrhythmias, and monitoring potassium levels.

In summary, understanding the mechanism of action, monitoring, and potential toxicity of digoxin is crucial for its safe and effective use in clinical practice.

Understanding Central Retinal Vein Occlusion

Central retinal vein occlusion (CRVO) is a common type of retinal vascular disorder that can lead to vision loss. It occurs when the vein that carries blood away from the retina becomes blocked, usually due to thickening of the adjacent arteriole. Risk factors for CRVO include arteriosclerosis and hyperviscosity.

Symptoms of CRVO include painless and unilateral visual loss, with more severe cases presenting with widespread retinal haemorrhages, engorged veins, retinal oedema, and a swollen optic disc. However, less severe cases may also occur.

It is important to differentiate CRVO from other retinal disorders, such as diabetic retinopathy, branch retinal vein occlusion, hypertensive retinopathy, and ocular ischaemic syndrome. Diabetic retinopathy is associated with retinal haemorrhages, but these are unlikely to be unilateral. Branch retinal vein occlusion affects only part of the retina, while hypertensive retinopathy should be bilateral and accompanied by other changes. Ocular ischaemic syndrome is a rare condition associated with severe carotid artery occlusive disease, causing dot-and-blot haemorrhages within the mid-periphery and dilated retinal veins.

In summary, understanding the symptoms and risk factors of CRVO can help with early detection and treatment, preventing further vision loss.

postoperative endophthalmitis is a rare but serious complication of cataract surgery that requires urgent treatment. It can have an infectious or non-infectious cause and should be considered in patients who experience acute pain, redness, visual loss, discharge, or photophobia after eye surgery. Due to the potential for vision loss, patients should be referred to an ophthalmologist for assessment on the same day. Prescribing prednisolone eye drops may worsen the condition if it is infectious, and chloramphenicol eye drops may delay specialist ophthalmology review and treatment. Referring the patient to be seen in two weeks is not appropriate due to the potential for visual morbidity. While optometrists can refer patients to ophthalmologists, referral to an ophthalmologist should be made without delay.

Understanding Cataracts

A cataract is a common eye condition that occurs when the lens of the eye becomes cloudy, making it difficult for light to reach the retina and causing reduced or blurred vision. Cataracts are more common in women and increase in incidence with age, affecting 30% of individuals aged 65 and over. The most common cause of cataracts is the normal ageing process, but other possible causes include smoking, alcohol consumption, trauma, diabetes mellitus, long-term corticosteroids, radiation exposure, myotonic dystrophy, and metabolic disorders such as hypocalcaemia.

Patients with cataracts typically experience a gradual onset of reduced vision, faded colour vision, glare, and halos around lights. Signs of cataracts include a defect in the red reflex, which is the reddish-orange reflection seen through an ophthalmoscope when a light is shone on the retina. Diagnosis is made through ophthalmoscopy and slit-lamp examination, which reveal a visible cataract.

In the early stages, age-related cataracts can be managed conservatively with stronger glasses or contact lenses and brighter lighting. However, surgery is the only effective treatment for cataracts, involving the removal of the cloudy lens and replacement with an artificial one. Referral for surgery should be based on the presence of visual impairment, impact on quality of life, patient choice, and the risks and benefits of surgery. Complications following surgery may include posterior capsule opacification, retinal detachment, posterior capsule rupture, and endophthalmitis. Despite these risks, cataract surgery has a high success rate, with 85-90% of patients achieving corrected vision of 6/12 or better on a Snellen chart postoperatively.

If systemic therapy is administered, topical antivirals are unnecessary. However, secondary inflammation may be treated with topical corticosteroids.

Herpes Zoster Ophthalmicus: Symptoms, Treatment, and Complications

Herpes zoster ophthalmicus (HZO) is a condition caused by the reactivation of the varicella-zoster virus in the area supplied by the ophthalmic division of the trigeminal nerve. It is a type of shingles that affects around 10% of cases. The main symptom of HZO is a vesicular rash around the eye, which may or may not involve the eye itself. Hutchinson’s sign, a rash on the tip or side of the nose, is a strong risk factor for ocular involvement.

The management of HZO involves oral antiviral treatment for 7-10 days, ideally started within 72 hours of symptom onset. Intravenous antivirals may be given for severe infection or if the patient is immunocompromised. Topical antiviral treatment is not recommended for HZO, but topical corticosteroids may be used to treat any secondary inflammation of the eye. Ocular involvement requires urgent ophthalmology review.

Complications of HZO include conjunctivitis, keratitis, episcleritis, anterior uveitis, ptosis, and post-herpetic neuralgia.

Antimicrobial treatment is often unnecessary for most cases of infective conjunctivitis, regardless of whether it is caused by a virus or bacteria. It can be challenging to differentiate between the two, although bacterial conjunctivitis may present with purulent discharge instead of watery discharge. Patients can alleviate symptoms with self-care measures such as cold compresses and ocular lubricants. If symptoms persist after seven days, patients should seek further medical attention. In severe cases of suspected bacterial conjunctivitis, chloramphenicol ointment can be purchased over the counter, while fusidic acid may be used as a second-line antimicrobial. Herpetic conjunctivitis, which causes a painful red eye with vesicular eyelid lesions, can be treated with aciclovir. Swabs are not useful in diagnosing conjunctivitis.

Infective conjunctivitis is a common eye problem that is often seen in primary care. It is characterized by red, sore eyes that are accompanied by a sticky discharge. There are two types of infective conjunctivitis: bacterial and viral. Bacterial conjunctivitis is identified by a purulent discharge and eyes that may be stuck together in the morning. On the other hand, viral conjunctivitis is characterized by a serous discharge and recent upper respiratory tract infection, as well as preauricular lymph nodes.

In most cases, infective conjunctivitis is a self-limiting condition that resolves on its own within one to two weeks. However, patients are often offered topical antibiotic therapy, such as Chloramphenicol or topical fusidic acid. Chloramphenicol drops are given every two to three hours initially, while chloramphenicol ointment is given four times a day initially. Topical fusidic acid is an alternative and should be used for pregnant women. For contact lens users, topical fluoresceins should be used to identify any corneal staining, and treatment should be the same as above. It is important to advise patients not to share towels and to avoid wearing contact lenses during an episode of conjunctivitis. School exclusion is not necessary.

Understanding the Afferent Pupillary Defect in Glaucoma

The afferent pupillary defect is a key diagnostic tool in glaucoma. It refers to differences in the afferent pathway between the two eyes, indicating retinal or optic nerve disease. This defect can be detected even if visual field testing is not positive, making it a valuable tool in diagnosing glaucoma.

Contrary to popular belief, the presence of neurosyphilis doesn’t necessarily indicate an afferent pupillary defect. Instead, the Argyll Robertson pupils, which are small, irregular pupils that constrict during accommodation but not in response to light, are a hallmark of neurosyphilis.

It is also important to note that the density of a cataract or intraocular pressure doesn’t affect the presence of an afferent pupillary defect. Even with a dense cataract or corneal scar, a positive test can still be obtained as long as the retina and optic nerve are healthy.

Finally, while miotic drugs like pilocarpine can be used to treat glaucoma, they do not cause an afferent pupillary defect. This defect is a result of underlying retinal or optic nerve disease and should be carefully evaluated by a healthcare professional.

Treatment for Age-Related Macular Degeneration

The National Institute for Health and Clinical Excellence (NICE) recommends Ranibizumab (Lucentis) as a treatment for certain types of vascular age-related macular degeneration. This treatment involves monthly intravitreal injections for the first three months, followed by monthly monitoring. While this treatment works for one-third of patients, most people maintain their vision.

For dry age-related macular degeneration, psychological support and low vision rehabilitation are recommended. Laser photocoagulation is not an option due to the risk of severe visual loss from laser damage. Smoking cessation is advised, but it is not a treatment.

High-dose vitamin and mineral supplements can slow progression, but they consist of vitamin C, vitamin E, beta-carotene (vitamin A), zinc oxide, and cupric oxide. It is important to note that vitamin D is not included in this treatment.

In summary, there are various treatment options available for age-related macular degeneration, depending on the type and severity of the condition. It is important to consult with a healthcare professional to determine the best course of action.