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.

Chlamydial Conjunctivitis: A Case for Prompt Referral

The presented case of a young patient with non-responsive conjunctivitis, ocular discharge, and pre-auricular lymphadenopathy should raise suspicion for chlamydial conjunctivitis. Therefore, a prompt referral to an ophthalmologist for further examination, investigation, and treatment is necessary. Once confirmed, management can be done jointly with a genito-urinary medicine specialist (GUM).

It is crucial to identify and treat chlamydial conjunctivitis promptly to prevent complications such as corneal scarring and vision loss. Therefore, clinicians should have a high index of suspicion for this condition, especially in sexually active individuals. Referral to an ophthalmologist and GUM specialist can ensure comprehensive management and prevent further spread of the infection. Proper education and counseling on safe sex practices should also be provided to prevent future occurrences.

Common Eye Conditions in Newborns

The nasolacrimal duct may not be fully developed in 5-10% of newborns, but it typically resolves on its own by 12 months. Cleaning the medial canthus is usually sufficient, and antibiotics are not effective unless an infection occurs. Surgery is rarely necessary.

Ophthalmia neonatorum is a type of conjunctivitis that occurs within the first 28 days of life. It can be caused by bacteria such as Chlamydia trachomatis, Neisseria gonorrhoeae, Staphylococcus aureus, and Streptococcus pneumoniae, as well as viruses like herpes simplex virus. If left untreated, it can lead to serious eye damage.

Allergic conjunctivitis is uncommon in infants under 1 year old, but viral and bacterial conjunctivitis can occur. Both eyes are typically affected, and in addition to eye discharge, the conjunctiva will appear inflamed.

Understanding Eye Conditions in Newborns

When a patient presents with a Subconjunctival haemorrhage, which is characterised by a distinct area of bleeding in one eye, it is important to provide reassurance and check their blood pressure. This condition is often caused by coughing, constipation, or high blood pressure. Treatment may involve using lubricating eye drops for dry eyes, while infective conjunctivitis can be treated with options 3 and 4. Patients with conjunctivitis typically experience itchy eyes.

Subconjunctival haemorrhages occur when blood vessels in the subconjunctival space bleed. These vessels typically supply the conjunctiva or episclera. Trauma is the most common cause, followed by spontaneous idiopathic cases, Valsalva manoeuvres, and several systemic diseases. While subconjunctival haemorrhages can look alarming, they are rarely an indicator of anything serious. They are more common in women than men, and the risk increases with age. Newborns are also more susceptible. The incidence of both traumatic and non-traumatic subconjunctival haemorrhages is 2.6%.

Risk factors for subconjunctival haemorrhages include trauma, contact lens usage, idiopathic causes, Valsalva manoeuvres, hypertension, bleeding disorders, certain drugs, diabetes, arterial disease, and hyperlipidaemia. Symptoms include a red eye, usually unilateral, and mild irritation. Signs include a flat, red patch on the conjunctiva with well-defined edges and normal conjunctiva surrounding it. The patch’s size can vary depending on the size of the bleed and can involve the whole conjunctiva. Traumatic haemorrhages are most common in the temporal region, with the inferior conjunctiva as the next most commonly affected area. Vision should be normal, including acuity, visual fields, and range of eye movements. On examination, the fundus should be normal.

The diagnosis of a subconjunctival haemorrhage is clinical. If there is no obvious traumatic cause, check the patient’s blood pressure. If raised, refer the patient appropriately. If the patient is taking warfarin, check the INR. If raised, refer for appropriate adjustments to the dose to bring the INR back into the target range. If you cannot see the whole border of the haemorrhage, it may be associated with an intracranial bleed or an orbital roof fracture. Further appropriate investigations should then be done, including a full cranial nerve exam looking for neurological signs as well as a CT head, after discussion with a senior. Recurrent or spontaneous, bilateral subconjunctival haemorrhages warrant investigations for bleeding disorders or other pathology.

Reassure the patient that subconjunctival haemorrhages are a benign condition that will resolve on their own in 2 to 3 weeks.

Understanding Color Blindness: Causes, Symptoms, and Implications for Daily Life

Color blindness is a condition that affects a person’s ability to distinguish certain colors. The most common form is the failure of red-green discrimination, which is caused by a hereditary X-linked recessive gene. While rare, failure of blue-yellow discrimination can also occur and is more commonly acquired. Monochromatic defects are even rarer, affecting only about 1 in 30,000 people.

Ageing can exacerbate pre-existing color vision deficiencies, but color blindness itself is not affected by ageing. Diagnosis of color blindness requires specialist referral in most cases, as the commonly used Ishihara plate test is limited in its ability to detect more complex diagnoses.

Color blindness can have implications for daily life, particularly in certain occupations. While drivers do not need to notify the Driver and Vehicle Licensing Agency, people with color vision deficiency may be prohibited from working in roles that require color-coded wires, reading dashboards correctly, or operating machinery.

Late-stage optic nerve disease can also affect color vision, but this symptom is usually noticed relatively late in the progression of the disease. Therefore, it is important to test color vision in suspected optic nerve lesions and thyroid eye disease, which can drive progressive optic neuropathy.

Common Symptoms of Nerve Palsies

A nerve palsy is a condition that affects the function of a specific nerve. There are different types of nerve palsies, each with their own set of symptoms. Here are some common symptoms associated with different types of nerve palsies:

Third Nerve Palsy: This type of palsy is characterized by ptosis (drooping of the eyelid), a dilated and unreactive pupil, and downward and outward displacement of the eyeball. The affected eye may also have a divergent squint.

Seventh Nerve Palsy: In this type of palsy, increased lacrimation (tearing) may be seen. The affected eye may also have difficulty closing, resulting in dryness and irritation.

Horner’s Syndrome: This type of palsy is characterized by enophthalmos (sunken appearance of the eye) and miosis (constriction of the pupil). Other symptoms may include ptosis and decreased sweating on one side of the face.

By understanding the common symptoms associated with different types of nerve palsies, individuals can seek appropriate medical attention and treatment.

The Argyll-Robertson pupil is a well-known pupillary syndrome that can be observed in cases of neurosyphilis. This condition is characterized by pupils that are able to accommodate but do not react to light. A helpful mnemonic for remembering this syndrome is Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA). Other features of the Argyll-Robertson pupil include small and irregular pupils. The condition can be caused by various factors, including diabetes mellitus and syphilis.

Mydriasis, which is the enlargement of the pupil, can be caused by various factors such as third nerve palsy, Holmes-Adie pupil, traumatic iridoplegia, phaeochromocytoma, and congenital conditions. Additionally, certain drugs like topical mydriatics such as tropicamide and atropine, sympathomimetic drugs like amphetamines and cocaine, and anticholinergic drugs like tricyclic antidepressants can also cause mydriasis. It is important to note that anisocoria, which is the unequal size of pupils, can also lead to apparent mydriasis when compared to the other pupil.

Understanding Third Nerve Palsy and Other Related Conditions

Third nerve palsy is a condition where the eye is displaced outwards and downwards, resulting in ptosis and mydriasis. Treatment with pilocarpine drops may not be effective in this case. Cluster headaches may cause miosis instead of mydriasis, while Horner syndrome presents with unilateral partial ptosis, miosis, and hemifacial anhidrosis. Opioid addiction may also cause mydriasis during acute withdrawal. Understanding these conditions and their symptoms can aid in proper diagnosis and treatment.

Common Causes of Visual Impairment: A Comparison of Vitreous Haemorrhage, Central Retinal Artery Occlusion, Branch Retinal Vein Occlusion, Commotio Retinae, and Vitreous Detachment

Vitreous Haemorrhage: Patients with vitreous haemorrhage often experience floaters and a red hue, and the blood appears as a cloud in the vitreous. This condition is commonly seen in patients with proliferative diabetic retinopathy, as well as those who have experienced trauma or have other causes of proliferative retinopathy. It may also be an early sign of retinal tears and detachment.

Central Retinal Artery Occlusion: Sudden loss of vision is the hallmark of central retinal artery occlusion. Fundoscopy reveals a pale retina due to retinal ischaemia, with the centre of the macula appearing as a cherry-red spot.

Branch Retinal Vein Occlusion: Fundoscopy reveals superficial haemorrhages, retinal oedema, and cotton-wool spots in a sector of retina drained by the affected vein. The obstructed vein is dilated and tortuous. Visual loss largely depends on the compromise to macular drainage, and peripheral occlusions may be asymptomatic.

Commotio Retinae: Commotio retinae, or Berlin’s oedema, is caused by blunt injury to the eye. Decreased vision in the injured eye occurs a few hours after the injury. The retina appears opaque and white in colour in the periphery, but the blood vessels are normal. It is usually self-limiting.

Vitreous Detachment: Vitreous detachment is the most common cause of light flashes and floaters, but not visual loss. A slit-lamp examination is mandatory to exclude retinal tears, which are present in about 10% of cases.

Supplements and Their Risks and Benefits

Previously recommended supplements contained beta-carotene, but it is no longer recommended for smokers and ex-smokers due to the possible increase in lung cancer risk. However, high-dose vitamin and mineral supplements may slow the progression of age-related macular degeneration. This includes vitamin C, vitamin E, beta-carotene (vitamin A), zinc oxide, and cupric oxide. Those who may benefit are those with advanced age-related macular degeneration or visual loss in one year and people with intermediate age-related macular degeneration who have extensive drusen.

It is important to note that high doses of beta-carotene can cause harmless yellowing of the skin, but it also increases the risk of urinary tract infections and stones and urinary retention. Beta-carotene has been associated with an increased risk of lung cancer in people who smoke or who have been exposed to asbestos. One study of 29,000 male smokers found an 18% increase in lung cancer in the group receiving 20 mg of beta-carotene a day for 5 to 8 years. Therefore, it is crucial to be aware of the risks and benefits of supplements before taking them.