Eye conditions & diseases: Questions and Answers

Dry eye is a condition in which the tear film is unstable or insufficient, either because too few tears are produced or because they evaporate too quickly, which leaves the surface of the eye irritated rather than adequately lubricated.

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It is a surface problem with consequences for vision, not just comfort. A poor tear film makes vision fluctuate, which is why dryness matters so much when measurements are being taken for surgery.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Dry eyes are caused by a mix of tear production, tear quality, eyelid and blinking behaviour, medication, general health and environment. In most people several of those contribute at once.

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Age and hormonal change are common contributors, which is why the tear film is assessed more carefully in older patients and taken seriously around menopause.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Screen time can contribute to dry eyes because people blink less often and less completely when concentrating on a screen, which allows the tear film to break up between blinks.

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The effect is about blinking behaviour rather than the light, which is why breaks that involve looking at something distant, and making a point of blinking fully, tend to help.

Sources American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Air conditioning can worsen dry eyes by lowering humidity and moving air across the surface of the eye, increasing evaporation. It aggravates an existing tendency more often than it creates one from nothing.

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This is a practical consideration in the UAE, where indoor air is conditioned for much of the year. Seating that keeps you out of a direct draught makes a measurable difference for some people.

Sources American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Contact lenses can cause or worsen dryness, because a lens sits on the tear film and can reduce oxygen reaching the surface while increasing evaporation. Symptoms often improve when lenses are reduced or stopped.

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Sources American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Dryness is a recognised side effect of LASIK, particularly in the early months, because the procedure affects the corneal nerves that contribute to tear production. It usually improves as the surface heals.

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Pre-existing dryness is the main reason this becomes a bigger problem for some people than others, which is why the ocular surface is measured before surgery rather than after.

Sources Peer-reviewed literature (via PubMed Central) , Peer-reviewed literature (via PubMed Central)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Dryness can occur after SMILE, as it can after any corneal procedure. Research comparing procedures suggests differences in the degree of early surface disturbance, and that research describes averages rather than predicting an individual.

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What is not in question is that pre-existing dryness affects the outcome either way, which is why the tear film is assessed first regardless of which procedure is being considered.

• Dry eye after SMILE Pro

Sources Journal of Ophthalmology (via PubMed Central) , Peer-reviewed literature (via PubMed Central) , Peer-reviewed literature (via PubMed Central)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Dry eye can usually be improved, though it is often managed rather than cured. Treatment depends on which part of the tear system is failing, which is why an assessment of the surface comes before a recommendation.

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Options range from lubricants and lid hygiene to prescription treatment, punctal plugs and procedures aimed at the eyelid glands. Which applies is determined by examining the surface rather than by the symptom description.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Dry eye is diagnosed from the history together with an examination of the ocular surface, which usually includes how quickly the tear film breaks up, how the eyelids and glands look, and sometimes a test of tear production.

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Sources American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Yes. An unstable tear film makes vision fluctuate, often improving briefly after a blink. That is why dryness has to be accounted for when measuring a prescription or planning surgery.

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Sources National Eye Institute, National Institutes of Health (US) , Peer-reviewed literature (via PubMed Central)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

There is no single period that applies to everyone. What matters is whether the surface has stabilised enough for the measurements to be reliable and for healing to be predictable, and that is judged from repeat examination.

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This is one of the situations where a clinic asking you to come back after treatment is doing the right thing, even though it delays what you came for.

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Sources Peer-reviewed literature (via PubMed Central)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

A cataract is clouding of the natural lens inside the eye, which scatters light and reduces the sharpness and contrast of vision. It develops gradually and is a normal part of ageing for many people.

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Because it affects contrast rather than only clarity, people often describe it first as glare, difficulty in dim light, or colours looking dull rather than as obvious blur.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology , National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Ageing is the most common cause of cataracts. Other contributors include diabetes, prolonged ultraviolet exposure, smoking, eye injury, certain medications and some inherited conditions.

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Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

The usual symptoms of cataract are gradually worsening vision, glare and halos around lights, more difficulty seeing in dim light, colours appearing washed out, and frequent changes in prescription.

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A characteristic pattern is that vision is worst where there is glare, such as driving at night or reading in a bright room, and better in soft, even light.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Cataract surgery is considered when the effect on your vision has become significant enough to affect what you need or want to do, and when you understand the benefits and risks.

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That is a deliberate description rather than a visual measurement threshold, because the decisions that matter are functional: driving, reading, working, going out alone. Two people with similar-looking cataracts may reasonably decide differently.

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Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Cataract surgery is usually performed with anaesthetic drops and sometimes additional sedation, and it is generally described as painless with some awareness of light and movement.

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Sources American Academy of Ophthalmology , National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

The operation itself usually takes a short time, and the visit as a whole takes longer. It is usually done as a day case, without an overnight stay.

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Sources National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Vision often improves within days of cataract surgery, and the eye continues to settle over several weeks. Restrictions on lifting, swimming and eye rubbing are typically in place for a period afterwards.

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Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

A cataract cannot come back, because the lens has been replaced. Some people do develop clouding of the capsule behind the new lens months or years later, which is treated with a short laser procedure.

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Sources American Academy of Ophthalmology , National Eye Institute, National Institutes of Health (US)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Intraocular lenses are broadly grouped into monofocal lenses, which focus at one distance, multifocal and extended depth of focus lenses, which spread the focus over a range, and toric versions of each, which correct astigmatism.

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The choice is a trade-off rather than a hierarchy. Lenses that extend the range of focus can reduce dependence on glasses, and they can also introduce halos or reduced contrast that not everyone tolerates. Which is the better lens depends on your eyes, your habits and how you feel about the trade.

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Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

A monofocal intraocular lens focuses at a single set distance, usually chosen for clear distance vision, so glasses are typically still needed for reading.

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Its advantage is optical simplicity, which usually means fewer visual disturbances such as halos compared with lenses that divide focus across distances.

Sources National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

A multifocal intraocular lens provides focus at more than one distance at the same time, which reduces dependence on glasses for near and intermediate vision.

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The trade-off is that dividing light between focal points can reduce contrast and produce halos, particularly at night. Not everyone adapts comfortably, so the decision is usually taken with a discussion rather than by default.

Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

An extended depth of focus lens stretches a single focal region over a range of distances rather than creating separate focal points. It is often described as a middle position between monofocal and multifocal designs.

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Where a multifocal lens creates distinct zones, an extended depth of focus design aims for continuity, which in principle means fewer of the halos associated with distinct zones. Individual tolerance still varies.

Sources National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

A toric intraocular lens is designed to correct astigmatism at the same time as replacing the lens, rather than leaving the astigmatism to be corrected with glasses or further surgery.

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Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Where astigmatism is present and significant, a toric lens is usually the option considered, since it corrects the corneal shape as well as replacing the clouded lens.

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Whether it is worth it depends on how much astigmatism you have and how much it bothers you. Measuring it properly beforehand is part of the assessment.

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Sources National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

It can, and the extent depends on the lens chosen and on your eyes. Distance vision is commonly much less dependent on glasses afterwards, while reading often still needs help unless a lens designed for a range of distances is used.

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Sources National Institute for Health and Care Excellence (UK) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Cataract surgery in Dubai is priced per clinic and depends heavily on the intraocular lens chosen, so a single figure would be misleading. The lens is usually the largest variable in the total.

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There is a practical difference from elective vision correction here: cataract surgery is treatment for a disease rather than an optional procedure, so it is more often covered by insurance. Whether it is covered in your case is a question for your insurer and the clinic.

• What a clinic quote should include

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Sources National Institute for Health and Care Excellence (UK)

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Cataract surgery is more likely to be covered than elective laser vision correction, because it treats a diagnosed condition. Cover still depends on your specific policy, its exclusions and its pre-authorisation rules.

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The practical step is to ask the clinic for the procedure and lens codes before contacting the insurer, since the answer often differs between a standard lens and a premium one.

• Insurance and elective surgery

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This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

Glaucoma is a group of conditions in which the optic nerve is damaged, usually in association with raised pressure inside the eye, and it typically affects peripheral vision before central vision.

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Because the loss starts at the edges and progresses slowly, most people notice nothing until it is advanced. That is the whole argument for measuring eye pressure and examining the optic nerve on a schedule rather than waiting for symptoms.

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology , Cochrane

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.

The common form of glaucoma usually has no symptoms until vision loss is advanced, which is why it is found by examination rather than by noticing something. A sudden painful red eye with blurred vision is a different, acute presentation that needs immediate care.

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Which symptoms need urgent care

Sources National Eye Institute, National Institutes of Health (US) , American Academy of Ophthalmology

This information is for educational purposes and does not replace an examination by a qualified eye-care professional.