The eyes have it

Damien O’Brien MPSI looks at the often underestimated importance of eye care in overall health

Introduction

The human eye is a complex organ responsible for detecting light and transmitting visual information to the brain via the optic nerve. It allows the use of visual information for various purposes, including sight, balance, and circadian rhythm regulation. Eye health is an important – and sometimes overlooked – component of overall health and wellbeing. Vision is fundamental in an individual’s day-to-day life, with impairment significantly reducing quality of life.

Pharmacists are accessible and knowledgeable healthcare professionals who play a critical role in promoting good eye care practices, identifying common ocular conditions, and guiding patients on appropriate treatment options or referring if necessary. This article explores the anatomy of the eye, good eye care practices, the importance of nutrition for eye health, common eye conditions and their management, and the role of pharmacists in eye care.1,2

Anatomy of the eye

The human eye is a complex organ with many important structures. Understanding these structures is essential for the management of common eye conditions. Several
key structures of the eye and their functions are outlined below.

• Sclera and choroid: Outer layers of the eye that help ensure light only enters via the eye’s optic axis.
• Cornea: A transparent outer layer that helps focus light into the eye and onto the retina.
• Iris and pupil: The iris is the coloured part of the eye that works with the pupil to control the amount of light entering the eye.
• Lens: A flexible and transparent structure that can adjust its shape to focus light onto the retina.
• Retina: A layer of photoreceptor cells at the back of the eye that is important for processing images.
• Macula: A part of the retina responsible for high-resolution vision.
• Optic nerve: Transmits information from the retina to the brain.

Other components of the eye are important for protection, nourishment, lubrication, and maintaining its shape.1

Good eye care practices

There are several habits individuals can adopt to help maintain good eye health and reduce the risk of disease. Undergoing regular eye examinations by an optometrist is important for the early detection of various conditions and for preventing vision loss. Wearing protective eyewear is also essential, with sunglasses protecting against ultraviolet (UV) light and safety goggles recommended when exposed to hazardous materials. Avoiding smoking helps reduce the risk of certain eye conditions.

Good hygiene is crucial in preventing eye infections and maintaining ocular health. Important practices include washing hands before touching the eyes, avoiding eye rubbing, practising proper make-up hygiene, and ensuring correct contact lens care. Adequate lighting helps to reduce eye strain and fatigue, particularly when reading. Finally, managing screen time can help alleviate digital eye strain.3

Nutrition

Nutrition is critical for maintaining eye health and preventing degenerative conditions. This can be supported through a balanced diet or supplementation if required. Vitamin A has antioxidant properties and supports retinal function, maintains corneal moisture, and reduces the risk of degenerative eye conditions. Vitamins C and E help protect the eye from oxidative damage, potentially lowering the risk of cataracts and age- related macular degeneration (AMD).

Omega-3 fatty acids are found in high concentrations in the retina, helping to prevent dry eye syndrome and reduce the risk of AMD. Zinc supports retinal function and may help prevent macular degeneration. Lutein and zeaxanthin are carotenoids that accumulate in the retina and have been shown to slow the progression of conditions such as AMD and cataracts. Finally, ensuring adequate hydration
is essential for maintaining moisture levels in the eyes, reducing irritation, and supporting overall eye health.4

Management of common eye conditions

There are several common eye conditions that can cause pain, irritation, and impaired vision, leading to a reduced quality of life for patients. Early diagnosis and appropriate treatment can significantly improve clinical outcomes and support better long-term eye health.

Dry eye syndrome

Dry eye syndrome is a multifactorial condition of the ocular surface characterised by a loss of homeostasis of the tear film. It can cause significant discomfort and visual disturbances for the patient. It is caused by insufficient tear production or poor tear quality, leading to dry and irritated eyes.

Several factors can contribute to dry eye syndrome, including prolonged screen use, age, certain medications (ie, antihistamines, beta- blockers, anticholinergic agents), allergies, decreased androgen levels, autoimmune conditions, smoke, pollution, and weather conditions.

Evaluation of signs and symptoms is usually sufficient for diagnosis. Non-pharmacological management of the condition can include using humidifiers, avoiding triggers, and making environmental adjustments. Artificial tear drops – containing agents such as carbomer, hydroxypropyl methylcellulose, or sodium hyaluronate – can be used to lubricate the eyes and relieve dryness and discomfort. Preservative-free ocular lubricants or ocular anti- inflammatory medications, such as cyclosporine or corticosteroids, may be used if other treatment options have failed.5

Blepharitis

Blepharitis is a common condition characterised by inflammation of the eyelids. Symptoms are often recurrent, involve both eyes and include discomfort, redness, and irritation of the eyelid margins. Blepharitis may be caused by bacteria, viruses, allergies, or skin conditions such as seborrhoeic dermatitis and rosacea. Chronic cases may reduce quality of life due to persistent discomfort and visual disturbances.

Maintaining good eyelid hygiene and avoiding triggers typically help to manage symptoms, reducing the frequency and severity of flare- ups. Ocular antibiotics may provide symptomatic relief and eliminate bacteria from the eyelid margin. Oral tetracyclines or macrolide antibiotics may be used if symptoms do not resolve with eyelid hygiene or are associated with rosacea. A short course of topical corticosteroids
may help reduce inflammation and alleviate symptoms, while artificial tears can be used to relieve dry eye symptoms if required.6

Conjunctivitis

Conjunctivitis is a common eye condition characterised by inflammation of the conjunctival tissue and is associated with symptoms such as ocular redness, pain, and discharge. Conjunctivitis can be categorised as infectious or non-infectious. Viral conjunctivitis accounts for most infectious cases, although bacterial and fungal causes are also possible. Allergens, toxins, and irritants are typically the underlying causes for non-infectious conjunctivitis.7

Patient education on hygiene measures is important to reduce the spread of infection in infectious conjunctivitis. Bacterial conjunctivitis is typically self-limiting, but treatment can be used to reduce the duration of symptoms. Ocular eye drops may be used to treat bacterial conjunctivitis, with fusidic acid, ofloxacin, chloramphenicol, and azithromycin all being treatment options.

Viral conjunctivitis is also typically self-limiting, with treatment focusing on symptomatic relief through the

use of cold compresses and ocular lubricants. Ocular antivirals, including aciclovir and ganciclovir, may be used if required, while oral antivirals, such as famciclovir and valaciclovir, may be considered in severe cases.

Allergen avoidance is the mainstay of allergic conjunctivitis management. Ocular antihistamines or mast cell stabilisers, such as olopatadine, ketotifen, and sodium cromoglycate, are effective in treating symptoms of allergic conjunctivitis. Oral antihistamines may be used to treat moderate-to-severe cases.7

Diabetic retinopathy

Diabetic retinopathy is a progressive microvascular complication of diabetes mellitus and results from chronic hyperglycaemia-induced damage to blood vessels in the retina. It is one of the leading causes of vision impairment and blindness. Diabetic retinopathy is classified into non- proliferative and proliferative forms. Non-proliferative diabetic retinopathy is characterised by microaneurysms, retinal haemorrhages, and macular oedema, while proliferative diabetic retinopathy is associated with neovascularisation and a higher risk of vision loss.

Prompt diagnosis and a thorough management plan are important in achieving good clinical outcomes. Management focuses on optimising systemic control of diabetes and its comorbidities, including achieving metabolic control, maintaining haemoglobin A1C (HbA1C) levels under 7 per cent, healthy diet, and engaging in regular exercise.

Adherence to antidiabetic medication, antihypertensives, and lipid- lowering agents is crucial to slow the progression of retinopathy.

In advanced cases, intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents, such as bevacizumab, ranibizumab, and aflibercept, are used to reduce macular oedema and inhibit neovascularisation. Early identification, close glycaemic control, and supportive therapy are essential to minimise disease progression and improve clinical outcomes.8

Glaucoma

Glaucoma is an eye condition characterised by elevated intraocular pressure (IOP) that may progress
to vision loss. It can be classified as either primary or secondary glaucoma, with secondary glaucoma arising from a previous eye injury or an underlying medical condition. Glaucoma can then be further classified into open-angle or closed-angle types, with primary open-angle glaucoma being the most prevalent. In glaucoma, drainage of aqueous fluid through the trabecular meshwork is impaired, leading to an increase in IOP, optic nerve damage, and progressive loss of vision.

Management of glaucoma should be individualised based on the type and severity of the disease. While treatment cannot reverse vision loss, it aims to reduce IOP and prevent further damage. Different classes of medications are used to lower IOP and preserve optic nerve function. These include prostaglandin analogues (latanoprost, bimatoprost, and travoprost), beta-blockers (timolol), carbonic anhydrase inhibitors (dorzolamide and brinzolamide), and alpha agonists (brimonidine and apraclonidine). Combination therapies may be used when monotherapy is inadequate.9

Cataracts

A cataract is a clouding of the clear lens of the eye, which obscures the passing of light through the lens
to the retina. It is characterised by blurred vision, glare, photophobia, and difficulty seeing in poor lighting. The condition can affect all age groups, but it predominately affects older people, with it being a significant cause of blindness. Cataracts can vary in severity and usually progress gradually, interfering with normal day-to-day activities and reducing quality of life. In initial stages of disease, treatment options include correction with refractive glasses or pupillary dilatation with cyclopentolate or atropine eye drops. Cataract surgery is the only definitive treatment if visual acuity declines, or if a cataract is adversely affecting eye health. Surgery involves removing the cloudy lens and replacing it with an artificial intraocular lens and typically has an excellent prognosis. Patients should be initiated on corticosteroid and antibiotic eye drops after surgery. Dexamethasone and prednisolone are commonly-used corticosteroids and should be administered in tapering doses. Lubricant eye drops may be administered as add-on therapy and the patient should be monitored for complications.10

Age-related macular degeneration (AMD) AMD is a condition that affects the central part of the retina and may lead to central vision loss. AMD is one of the leading causes of blindness, and particularly affects older adults. Age is the primary risk factor associated with this condition, with smoking also an independent risk factor. AMD can be classified into dry (non-neovascular) AMD and wet (neovascular) AMD.

Various imaging techniques are used in the diagnosis of AMD, with regular monitoring essential in
the early stages to identify signs of progression of the condition. Nutritional supplements may have some effectiveness in slowing the progression of AMD. Intravitreal anti-VEGF injections, such as bevacizumab, ranibizumab, and aflibercept, are the main treatment option for wet AMD. These agents can slow progression of the disease, improve visual acuity, and improve quality of life.11

Role of the pharmacist

Pharmacists are ideally placed in the community to provide guidance on eye health, including preventative care, management of minor ailments, and referral to another healthcare professional when necessary. Many eye drops, including artificial tears, antihistamine drops, and antibiotic eye drops, are available over the counter, and pharmacists can recommend appropriate treatment for patients based on their symptoms.

Pharmacists can also identify symptoms that require urgent medical attention and refer when necessary. Furthermore, they can educate patients on lifestyle modifications, including smoking cessation, UV protection, and screen time reduction, to improve overall eye health.

Pharmacists can also offer support to patients with chronic eye conditions, promoting adherence to prescribed medication and demonstrating eye drop administration techniques. Finally, pharmacists can collaborate with other healthcare professionals to contribute to reducing the burden of eye diseases and improving clinical outcomes for patients.