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Eye conditions
Eye conditions & diseases: Questions and Answers
Dry eye, cataract, glaucoma, keratoconus, retinal and diabetic eye disease explained: what each condition is, how it is diagnosed, and why some of them change which vision correction options are open to you.
Dry eye, cataract, glaucoma, keratoconus, retinal and diabetic eye disease explained: what each condition is, how it is diagnosed, and why some of them change which vision correction options are open to you.
General educational information. It does not replace an examination, and it cannot tell you what is happening in your own eyes.
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Eye conditions
Two things decide whether a vision correction procedure is a reasonable idea: the shape of your cornea, and the health of everything else. This section is about the second one.
Several conditions here are silent for a long time. That is the argument for a full eye examination rather than a refraction test when you are considering surgery, and it is also why an assessment sometimes ends with "let us treat this first".
Eye conditions & diseases questions and answers
Eye conditions
Dry eye, cataract, glaucoma, keratoconus, retinal and diabetic eye disease explained: what each condition is, how it is diagnosed, and why some of them change which vision correction options are open to you.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 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.
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.
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.
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.
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.
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.
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.
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.
Ageing is the most common cause of cataracts. Other contributors include diabetes, prolonged ultraviolet exposure, smoking, eye injury, certain medications and some inherited conditions.
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.
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.
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.
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.
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.
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.
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.
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.
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.
A monofocal intraocular lens focuses at a single set distance, usually chosen for clear distance vision, so glasses are typically still needed for reading.
Its advantage is optical simplicity, which usually means fewer visual disturbances such as halos compared with lenses that divide focus across distances.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Cataract surgery removes the clouded natural lens through a small incision and replaces it with an artificial intraocular lens. The replacement lens stays in the eye permanently, and its power is calculated before surgery from measurements of your eye.
Most cataract surgery is performed with ultrasound energy that breaks up the clouded lens so it can be removed through a very small wound, rather than by removing the whole lens in one piece as older techniques did. The incision is usually small enough that it does not need stitches.
What this depends on
How much the cataract affects your daily vision
The health of the rest of the eye
Which lens type is appropriate for your eyes and your life
Cataract surgery is one of the most commonly performed operations, and complications are uncommon. The recognised ones include inflammation, raised pressure in the eye, swelling of the retina, infection, and a change in the position or clarity of the implanted lens. Most are treatable if they are identified.
Two things lower the chance of a problem being missed: keeping the follow-up appointment in the first days after surgery, and contacting the clinic about new pain, a sudden drop in vision or a red eye rather than waiting for the next scheduled visit.
What this depends on
The health of the cornea and the retina going into surgery
The density of the cataract and the complexity of the case
Any condition that affects healing, such as diabetes
By examining the lens with a slit lamp, usually after the pupil is dilated. That examination shows whether the clouding is present and how much of the lens is affected; a change in the glasses prescription and reduced contrast sensitivity are common earlier findings.
The diagnosis and the decision to operate are two different decisions. A cataract that is visible but not affecting what you do may reasonably be watched, and many people live with an early cataract for years.
Some cataract surgery is performed with a femtosecond laser assisting parts of the operation, and the great majority is performed with ultrasound energy alone. Both approaches remove the same clouded lens; what differs is how the incision and the opening in the lens capsule are made.
If a clinic offers laser-assisted cataract surgery at a higher price, it is reasonable to ask what it changes for your eye specifically, and whether the surgeon expects a different outcome rather than a different technique.
What this depends on
The density of the cataract
The shape of your cornea and the size of your pupil
What the surgeon who examines you uses for cases like yours
Often both eyes eventually need it, but not usually on the same day. Most surgeons operate on one eye at a time, with the second eye treated once the first has settled, so that the eye that is healing is not the only eye you have to see with.
The interval between the two operations is a clinical decision and varies. What is worth planning for is that the second eye will need its own assessment and its own measurements, because the two eyes are rarely identical.
What this depends on
How much each eye is affected
Whether you could manage if one eye were temporarily blurry
Laser eye surgery reshapes the cornea, the clear window at the front of the eye. Cataract surgery replaces the lens, the structure behind the iris. They treat different parts of the eye for different reasons, and one does not substitute for the other.
People sometimes assume cataract surgery will also remove their need for glasses. It can reduce it, and with a multifocal or extended-depth-of-focus implant it can remove much of it, but that is a property of the lens chosen rather than of the operation.
What this depends on
Whether the blur is coming from the cornea or from the lens
Usually it is the wrong order. Laser vision correction changes the cornea, which makes the measurements used to choose a lens implant less predictable; if a cataract is already affecting your vision, replacing the lens addresses both problems at once.
An early cataract that is not yet affecting vision is a different case, and some people in that position are treated. The deciding question is whether the lens will need replacing within the useful life of the laser correction.
What this depends on
How much the cataract is affecting vision now
Your age, and how long a laser result would be relied on
What the measurements predict about the lens implant
It is clouding of the capsule that holds the implanted lens, months or years after surgery, and it is not the cataract returning: the natural lens was removed. It is common, it is treated with a short laser procedure in the clinic, and it does not usually need surgery again.
This is worth knowing in advance because the symptom, vision slowly misting over again, is easily mistaken for something more serious. A clinic appointment establishes what it is, and the treatment is quick.
Refractive lens exchange removes a clear natural lens and replaces it with an artificial one, to correct a prescription rather than to treat a cataract. It is the same operation as cataract surgery, performed earlier, and it is usually considered when the lens is no longer able to change focus anyway.
Because it is irreversible, the case for it rests on what you gain: a prescription corrected and reading vision addressed with a lens designed for both. The trade-offs are the same ones that come with any multifocal implant, and they should be discussed before booking, not after.
What this depends on
Your age and the state of your reading vision
Which implant your measurements support
Whether a laser option would achieve the same with less intervention
An implantable lens is a corrective lens placed inside the eye in front of your natural lens, without removing it. It is used most often for higher prescriptions where laser surgery would remove too much corneal tissue, and the natural lens remains in place.
Because the natural lens stays, reading vision changes with age exactly as it would have done otherwise, and the implant can be removed or exchanged if that becomes necessary. It is an intraocular operation, so it carries the small risks of entering the eye rather than the risks of reshaping the surface.
What this depends on
The size of your prescription and your corneal thickness
The depth of the front chamber of the eye
Whether your natural lens is still clear, and your age
From measurements of the length of your eye and the curvature of your cornea, taken before surgery and entered into a formula that predicts the power needed. Because the prediction is not exact, the surgeon will usually aim for a small residual, and will tell you which direction the estimate is likely to fall.
What this depends on
The measurements themselves, and how repeatable they were
Whether you have had previous laser surgery, which changes the calculation
What you would prefer the residual to be used for: distance or near
It can be, for the right eye and the right expectations. Lenses that give useful vision at more than one distance usually reduce dependence on glasses, and usually trade some contrast or night vision for it. Whether that trade is worth it depends on what you do with your eyes.
The useful question is not which implant is best but which implant suits you: someone who drives at night for a living and someone who reads all day should not be given the same recommendation, and a clinic that recommends one design to everybody has answered the wrong question.
What this depends on
How much night driving you do
How much you mind wearing glasses for some tasks
The health of your retina and cornea, which limits some designs
A standard single-vision implant is usually inside what health insurance covers when cataract surgery is medically indicated. The additional cost of a lens chosen for a refractive purpose, like a multifocal or toric design, is often treated as an upgrade and charged separately.
That distinction is worth getting in writing before surgery, because the difference between the two quotes is usually the lens rather than the operation. Ask the clinic to itemise the lens and to state what the policy covers.
What this depends on
Whether the surgery is medically indicated or refractive
The terms of your specific policy and pre-approval
Whether the lens is classed as standard or premium
A toric implant corrects astigmatism at the same time as replacing the lens. It carries a specific orientation that has to be aligned to the axis of your astigmatism during surgery, and it is worth asking how that alignment is checked in the clinic treating you.
What this depends on
How much corneal astigmatism you have
Whether the axis is stable
Whether the extra cost is covered or paid separately
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.
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.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsGlaucoma
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Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
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.
Glaucoma and the treatments for it can affect the measurements used in refractive planning, so it needs to be assessed and disclosed. It does not automatically rule surgery out, and it does change how the assessment is interpreted.
Keratoconus is a condition in which the cornea thins and becomes progressively more cone-shaped, which distorts vision and cannot be fully corrected with ordinary glasses in many cases.
It usually appears in the teenage years or early twenties. Because it progresses, the important part of management is detecting it and monitoring it rather than simply correcting the vision it causes today.
Laser vision correction is generally avoided in keratoconus because removing corneal tissue from a cornea that is already thinning and unstable is likely to make matters worse. This is one of the clearest contraindications in refractive surgery.
Keratoconus is detected with corneal topography and tomography, which map the shape and thickness of the cornea. This is a standard part of a refractive assessment and one of the main reasons those scans are done.
Detecting a mild or suspected case is one of the genuinely valuable outcomes of a careful assessment, because it changes the recommendation before anything irreversible has happened.
The retina should be examined because a refractive assessment is also an opportunity to find conditions that have nothing to do with the cornea and that would change how your eyes are managed, particularly in higher short sightedness.
Macular degeneration is damage to the central part of the retina, which affects fine detail such as reading and recognising faces while peripheral vision remains.
There are two main forms, a dry form that progresses slowly and a wet form that can worsen quickly and needs prompt treatment. Distinguishing them requires examination and imaging.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsRetina & macula
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Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
Flashes of light are often caused by the gel inside the eye pulling on the retina. New flashes, or flashes with a sudden increase in floaters or a shadow across the vision, need urgent assessment.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsRetina & macula
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Thank you. We use this to decide what to improve.
Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
The pattern that needs urgent assessment is a sudden increase in floaters, new flashes of light, or a dark shadow or curtain moving across part of the vision. These should be assessed the same day rather than booked routinely.
This is one of the few eye presentations where hours genuinely matter. The knowledge base cannot examine an eye, so the only responsible advice is to have it looked at urgently rather than to wait and see.
An OCT scan uses light to build a cross-sectional image of the retina, which shows its layers and any fluid or thinning that a photograph would not reveal. It is quick and does not touch the eye.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsRetina & macula
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Thank you. We use this to decide what to improve.
Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
The retina separating from the wall of the eye, which threatens vision if it is not treated. The warning sign is often a sudden increase in floaters, new flashes of light, or a shadow or curtain moving across the vision, and it needs urgent assessment rather than a routine appointment.
This is the symptom pattern where the timing genuinely matters. Treatment is far more effective before the central retina is involved, so “sudden” plus “floaters, flashes or a curtain” is a reason to act today.
What this depends on
How sudden the change was
Whether a shadow or curtain is present
Whether you are short sighted or have had previous eye surgery
Diabetes can damage the small blood vessels in the retina, a condition called diabetic retinopathy, and it also raises the risk of cataract and of other eye problems. It can progress without symptoms.
This is why retinal screening is recommended at regular intervals for people with diabetes, and why good control of blood sugar and blood pressure is part of looking after the eyes rather than separate from it.
Diabetes does not automatically rule out refractive surgery, but it changes the assessment: the retina is examined carefully, and stability of blood sugar matters because it affects both the measurements and healing.
Some clinics ask for documented control and a recent retinal examination before proceeding. That is a reasonable request rather than an obstacle.
Yes. Fluctuating blood sugar can change the shape of the lens and produce temporary blur that shifts as control changes, and diabetic eye disease can also reduce vision. Blur in someone with diabetes deserves an examination.
Damage to the small blood vessels of the retina caused by diabetes, which can leak or become blocked, and in more advanced stages grow new vessels. It develops silently, which is why it is found by screening rather than by noticing a change in vision.
Conjunctivitis is inflammation of the clear membrane covering the white of the eye and the inside of the eyelids. It can be infective, allergic or irritant, and the treatment differs substantially between those.
Because the causes look similar, a red eye that is painful, light sensitive or associated with reduced vision is assessed rather than assumed to be simple conjunctivitis.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsInfections, allergies & injuries
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Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
A red eye needs urgent assessment when it is accompanied by significant pain, reduced vision, light sensitivity, a feeling that something is stuck in the eye, or contact lens wear.
A red eye without pain or vision change in someone who does not wear contact lenses is usually less urgent. Contact lens related redness is treated more cautiously because of the risk of corneal infection.
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
Eye conditionsInfections, allergies & injuries
Was this answer helpful?
Thank you. We use this to decide what to improve.
Some sudden eye symptoms need urgent assessment
This answer explains what the symptom commonly indicates. If it has come on suddenly, or is
accompanied by pain or loss of vision, seek urgent care rather than waiting for an appointment.
Yes. Contact lens wear is a recognised risk factor for corneal infection, and the risk rises sharply with overnight wear, with tap water contact and with poor lens case hygiene.
Pain, light sensitivity or reduced vision in a contact lens wearer is a reason to remove the lens and seek prompt assessment rather than to wait overnight.
A stye is an infection at the base of an eyelash, and a chalazion is a blocked oil gland in the eyelid. Both produce a tender or firm lump, and most settle with warm compresses.
One that enlarges, keeps returning, or affects vision should be examined rather than repeatedly treated at home.
Itchy, watery eyes usually point to allergy rather than infection, and allergy treatment differs from infection treatment. The itch is the distinguishing feature for most people.
This matters in Dubai, where seasonal and indoor allergen exposure can be significant for part of the year.
Inflammation of the eyelid margins, usually involving the oil glands that open along the lid edge. It causes crusting, redness, a gritty sensation and fluctuating vision, and it is chronic and managed rather than cured: lid hygiene and warm compresses are the mainstay.
What this depends on
Whether the oil glands are blocked or the skin is inflamed
Whether there is also a skin condition such as rosacea
These answers describe what is generally true. They are not a diagnosis and they cannot say
whether a treatment is suitable for you, because suitability depends on measurements taken during
an examination. Only a qualified ophthalmologist who has examined you can decide.
A meta-analysis pooling several studies on dry eye after SMILE compared with femtosecond LASIK. It also documents where the included studies disagreed.
Used for The dry-eye discussion on the comparison and risks pages; Explaining that the evidence base is mixed rather than unanimous.
Link checked 22 September 2026
Dry Eyes After SMILE Peer-reviewed literature Peer-reviewed literature (via PubMed Central)
A review of ocular surface changes after SMILE, including how dry-eye signs and symptoms are measured and how they change over the first postoperative months.
Used for Explaining why dry eye is a key preoperative consideration.
The UAE government’s own listing of the federal health authority and of the emirate-level health authorities, naming which part of the country each one covers.
Used for Explaining that more than one authority licenses healthcare in the UAE; Explaining which body to approach about a licensed facility.
Link checked 24 September 2026
Related pages
These pages go deeper on the questions that usually follow this one.