Thread by @1goodtern

Stan Laurel said your eyes are the windows to your soul.

I don't know about that, but I do know that your body is really complicated, but your eyes... yeah, your eyes are something else.

An orbital disorder is a problem affecting the eye socket. It can involve swelling, pressure, pain, double vision, or inflammation around the muscles and tissues that move the eye.

Covid makes these problems more likely because it can trigger strong inflammation in the tissues behind the eye and can affect the blood vessels and nerves that run through the orbit. That extra inflammation means more people needing hospital care for eye socket pain or pressure.

A deformity of the orbit means the shape or structure of the eye socket has been altered. This can happen when repeated inflammation or pressure changes affect the bones and soft tissues around the eye.

Covid increases this risk because it can trigger strong inflammatory reactions in the tissues that support the eye. Over time those flare ups can cause swelling, weakening, or changes in the structure of the orbit, which leads to more people needing hospital care.

Ectropion is when the eyelid droops outward instead of sitting against the eye. It leaves the eye exposed, dry, irritated, and more likely to get infections or damage, which often means hospital treatment in older adults.

Covid makes this more common because it weakens the tissues and nerves that control the eyelid and increases inflammation in the skin around the eye. That combination pushes more older people into needing help for eyelids that no longer close or protect the eye properly.

The lacrimal gland makes tears. When it is inflamed or not working properly, the eyes become dry, painful, swollen or watery. In older adults this often leads to repeated appointments or hospital treatment.

Covid can damage this gland directly and can inflame the small ducts and tissues around it. It also disrupts the immune system in ways that trigger dry eye and tear gland swelling. That is why there has been such a sharp rise in tear gland disorders in people over 70.
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Exophthalmic conditions are problems where the eye bulges forward. In children this can happen when the tissues behind the eye become swollen or inflamed, putting pressure on the eyeball.

Covid increases this risk because it can inflame the tissues and blood vessels in the orbit and can trigger immune reactions that swell the space behind the eye. That is why more young children are ending up in hospital with eye bulging or pressure symptoms.

This category covers a range of eyelid problems, including swelling, infections, inflammation, drooping, and issues with the glands and skin around the lid. These problems often need medical treatment when they interfere with vision or eye comfort.

Covid raises the risk because it drives inflammation in the skin, nerves, and small blood vessels of the eyelid. It also disrupts tear production and immunity at the surface of the eye. All of this increases the number of people needing hospital care for eyelid disorders.

These are degenerative conditions affecting the eyelid and the tissues around the eye. They involve gradual weakening, thinning, or damage to the skin, glands, muscles, or connective tissue that supports the eyelid.

Covid speeds this up by driving chronic inflammation and damaging the small blood vessels and nerves that keep these tissues healthy. Repeated infections add extra strain, which is why more people are now needing hospital care for eyelid degeneration.

These are other disorders of the orbit in young children. They include swelling, infections, inflammation, and problems with the tissues that sit behind the eye and help control its movement.

Covid raises the risk because it can inflame the space behind the eye, affect the small blood vessels and nerves, and trigger immune reactions that put pressure on the orbit. That is why more children are now turning up with these eye socket problems.

A conjunctival haemorrhage is when a small blood vessel on the surface of the eye bursts, leaving a bright red patch. In children it can follow coughing, infections, inflammation or changes in blood pressure.

Covid makes this more common because it raises inflammation in the tiny blood vessels of the eye and causes strong coughing fits and pressure swings. It also affects clotting and vessel strength. All of this leads to more children turning up with burst vessels on the eye.

Chronic conjunctivitis means long lasting inflammation of the thin tissue that covers the white of the eye. In children it causes redness, irritation, discharge, and repeated flare ups that can last for months.

Covid increases this risk because it disrupts tear film, inflames the surface of the eye, and weakens local immunity. Each infection can trigger another long spell of irritation, so more children are ending up with persistent conjunctivitis that needs hospital care.

These are problems with the tiny blood vessels and cysts on the surface of the eye. In children they show up as red patches, swelling, small lumps, or areas where fluid collects under the conjunctiva.

Covid increases these because it injures small vessels, affects clotting, and drives inflammation in the surface layers of the eye. That makes vessel leaks and cysts more common, so more children end up needing hospital checks or treatment.

Corneal degeneration means the clear front surface of the eye starts to thin, weaken, or become cloudy. In children it can affect vision, cause pain or light sensitivity, and often needs specialist care.

Covid raises this risk because it inflames the cornea, disrupts the tear film that protects it, and can damage the cells that keep the surface healthy. Repeated infections add more stress, which is why more children are now turning up with early corneal changes.

Herpesviral keratitis is a viral infection of the cornea, and keratoconjunctivitis means the infection also spreads to the surface lining of the eye. In children it can cause pain, light sensitivity, blurred vision, and can leave permanent scarring.

Covid increases the risk because it weakens local immunity around the eyes and can trigger reactivation of herpes viruses that were lying quiet. Each Covid infection gives these viruses an easier chance to flare up, which is why more children are ending up in hospital with herpes eye infections.

Corneal pigmentations and deposits are small spots or patches that build up on the clear front surface of the eye. In children they can interfere with vision, cause glare, or signal that the cornea has been irritated for a long time.

Covid increases this risk because it inflames the cornea, disrupts the tear film, and damages the surface cells that normally keep it clear. Repeated infections make these deposits more likely to form, so more children are now being seen in hospital with them.

A corneal ulcer is an open sore on the clear surface of the eye. In teenagers it can cause severe pain, redness, blurred vision, and can leave permanent scarring if it is not treated quickly.

Covid makes this more likely because it weakens local immunity, dries out the eye, and increases the chance of infections taking hold on the cornea. Repeated Covid infections add more stress, which is why more young people are now turning up with corneal ulcers.

A corneal scar or opacity is a patch on the clear surface of the eye where the tissue has been damaged and healed imperfectly. In teenagers this can blur vision, cause glare, and sometimes needs surgery.

Covid increases this risk because it leads to more corneal infections and inflammation, and those conditions often leave scars behind. Each infection adds another chance for damage, which is why corneal scarring in young people has risen so sharply.

Central corneal opacity means a patch of cloudiness right in the middle of the cornea, the part needed for sharp vision. In teenagers it usually appears after infections, inflammation, or injuries to the eye surface.

Covid raises this risk because it causes more corneal infections, more inflammation, and more damage to the surface cells that keep the cornea clear. When those areas heal, they can leave a central cloudy patch, which is why these cases have risen.

These are vascular problems and cysts on the surface of the eye in young and mid age adults. They show up as red patches, broken vessels, or small fluid filled lumps that cause irritation or blurred vision.

Covid increases these because it injures tiny blood vessels, affects clotting, and inflames the surface layers of the eye. Each infection adds more strain on these vessels, which is why far more adults are now needing hospital care for these conjunctival problems.

Ocular pemphigoid is an autoimmune disease where the body attacks the surface of the eye. It causes chronic redness, scarring, irritation, and can make the eyelids stick to the eye if it gets severe.

Covid increases the risk because it can trigger or worsen autoimmune reactions. It disrupts immune control and raises inflammation, giving conditions like ocular pemphigoid more chances to start or flare. That is why more younger adults are now showing up with this once rare problem.

Scleritis is deep inflammation of the white outer wall of the eye. It causes severe pain, redness, light sensitivity, and can threaten vision if it is not treated fast. It is usually linked to immune system problems.

Covid makes this more likely because it ramps up inflammation and can disrupt immune control, pushing the body toward autoimmune flare ups. Each infection adds more immune stress, which is why more young adults are now turning up with painful scleritis.

Episcleritis is inflammation of the thin layer of tissue on top of the white part of the eye. It causes redness, irritation and discomfort, and often needs medical care when it keeps coming back.

Covid raises this risk because it triggers strong immune reactions and inflammation in small blood vessels. Each infection can set off another flare, which is why more young adults are now turning up with recurrent episcleritis.

Corneal ulcers again:

Superficial keratitis is inflammation of the top layers of the cornea. It causes pain, light sensitivity, watering, and blurred vision, and often flares up again and again in younger adults.

Covid raises this risk because it disrupts the tear film, injures surface cells, and weakens local immunity. Each infection makes the cornea more vulnerable, which is why more adults are ending up in hospital with these painful surface flare ups.

More corneal pigmentations, this time in young adults:

Changes in corneal membranes are problems with the thin layers on the surface and just beneath the surface of the cornea. These layers can thicken, wrinkle, or become cloudy, and that can affect comfort and vision in younger adults.

Covid raises this risk because it inflames the cornea, disrupts the tear film, and damages the cells that repair these surface layers. Repeated infections give these membrane changes more chances to develop, which is why cases have risen.

Hereditary corneal dystrophies are genetic conditions where the layers of the cornea slowly become cloudy, irregular, or lose function. They often run in families and can cause blurred vision, glare, or recurrent pain.

Covid does not change the genes, but it does inflame and stress the cornea. That stress can unmask or accelerate underlying dystrophies, making symptoms appear earlier or flare more often. That is why more younger adults with these inherited corneal problems are now needing hospital care.

Acute atopic conjunctivitis is a severe allergic flare of the surface of the eye. It causes intense redness, swelling, itching, watering, and sometimes even blurred vision. In mid age adults it can be strong enough to need hospital care.

Covid raises this risk because it disrupts immune balance and increases inflammation in the tissues around the eye. After infection, the immune system becomes more reactive, so allergic eye flares become more frequent and more severe.

A pterygium is a wedge of thickened tissue that grows from the white of the eye onto the cornea. It can cause redness, irritation, and blurred vision, and often needs surgery when it grows too far.

Covid increases this risk because it drives chronic inflammation on the eye surface and disrupts the tear film that normally protects against this kind of overgrowth. Repeated infections give that tissue more chances to thicken and spread, so more mid age adults now need treatment for pterygium.

Conjunctival degenerations and deposits are changes where the clear surface tissue of the eye becomes thickened, cloudy, or develops small lumps or calcified spots. In mid age adults these can irritate the eye or interfere with vision.

Covid raises this risk because it inflames the surface layers of the eye and disrupts the tear film that normally keeps these tissues healthy. Repeated infections make degeneration and deposits more likely to form, which is why cases have risen so sharply.

Conjunctival vascular disorders and cysts in older working adults:

An adherent leukoma is a dense white scar on the cornea that sticks to the iris underneath. It usually forms after a severe infection or injury and can cause major vision loss in mid age adults.
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Covid raises this risk because it leads to more corneal infections, ulcers, and inflammation. When those heal, they can leave deep scars that attach to the iris. That is why these once rare cases are now rising.

Corneal pigmentation and deposits in older working adults:

Corneal oedema is swelling of the clear front surface of the eye. It makes the cornea waterlogged and cloudy, causing blurred vision, glare, pain, and halos around lights. In mid age adults it often needs hospital treatment.

Covid raises this risk because it damages the cells that pump fluid out of the cornea and keep it clear. It also causes inflammation and pressure changes that make swelling more likely. Repeated infections push more people into corneal oedema.

Corneal membrane changes in older adults:

Corneal degeneration in older working adults:

Keratoconus in older working adults

Here is acute atopic conjunctivitis in older adults. Before the pandemic the numbers bounced around a fairly steady baseline. Then Covid arrives and the trend shifts. The immune disruption Covid causes increases allergic and inflammatory responses in the eye, and that shows up here as a clear rise in hospital episodes.

Covid affects mast cells, barrier tissues, and local immune signalling. That means even conditions that look purely allergic can be pushed into more severe or persistent territory after infections. The spike in older adults fits with what we see across many systems. Covid strips away resilience and reveals underlying vulnerabilities.

Pterygium in older adults. Notice how the same post-Covid acceleration shows up again, even in an age group where the baseline is already high and changes are usually slow. The pattern is consistent: stable pre-Covid, then clear upward shifts after repeated infection waves.

Conjunctival degenerations and deposits in older adults. The same post-Covid jump shows up again here, but even more sharply. A condition that used to rise slowly with age suddenly accelerates after repeated Covid waves, suggesting disrupted healing and chronic inflammation are playing a major role.

This chart shows other specified disorders of the conjunctiva in adults aged 70 plus. These are problems with the thin membrane that lines the white of the eye, often involving irritation, swelling, small growths or inflammatory changes that are not tied to one single cause.

Covid infection makes these problems more likely because it damages small blood vessels, disrupts tear film, and drives long lasting inflammation in surface tissues. In older adults this hits harder, because healing is slower and immune regulation is less flexible, so repeated infections can push these conditions sharply upwards.

Adherent leukoma in older adults. This is the same condition we saw in the younger groups, but the shift here is even more extreme. A condition that was almost flat for a decade surges only after repeated Covid waves. This is exactly the sort of scar-forming, inflammation-driven process that Covid is known to worsen in the eye's surface tissues.

Corneal scarring in older adults.

Corneal pigment and deposit accumulation in older adults.

Corneal oedema in older adults

Changes in corneal membranes in older adults.

Corneal degeneration in older adults.

Adherent leukoma across all ages.

Corneal pigmentations and deposits across all ages.

Changes in corneal membranes across all ages.

Other corneal oedema, all ages

Corneal scar and opacity (all ages).

Conjunctival degenerations and deposits (all ages)

Pupillary membranes are thin sheets of tissue that should disappear before birth. When they persist or reform, it usually signals inflammation inside the eye. Covid is well known to trigger persistent inflammatory responses, including in very small vessels and delicate ocular structures.

Even mild infections in children can cause short, sharp bursts of inflammation that destabilise tissues that were previously quiet.

Children have more reactive immune systems, so Covid driven inflammation hits them differently: faster onset, more swelling, more tissue debris, and a higher chance of membranes reforming. This is what post-viral eye inflammation looks like when you track it over years.

These adhesions and disruptions usually follow inflammation inside the eye. Covid can inflame the iris and ciliary body, making the tiny membranes more likely to stick, swell, or tear.

The flat pre-Covid baseline speaks for itself. After repeated infections, inflammatory episodes spike in teens, who often mount strong immune reactions. That is why you suddenly see these jumps.

This one is iridocyclitis in young children. It is inflammation of both the iris and the ciliary body, and it often follows viral infections. Covid hits these tissues because they carry ACE2 and TMPRSS2, so the virus can trigger strong inflammatory flares.

Before Covid these numbers barely moved. After repeated waves, you suddenly see sharp rises in under-10s. Kids have narrow drainage angles and very reactive immune systems, so even small inflammatory surges cause trouble. This is exactly what you would expect when a virus keeps returning every few months.

Pupillary membranes in older children and teenagers

This time it is other disorders of the iris and ciliary body linked to systemic disease. These tissues are packed with immune cells, and Covid’s knack for triggering post-viral inflammation shows up here too.

When you see years of zeros, ones and twos turn into a clear spike in teenagers, you are looking at a new inflammatory burden. It mirrors what we are seeing across cornea, conjunctiva and uvea: Covid reinfections are not benign for ocular immune function, especially in young people.

Iridocyclitis is inflammation of the iris and ciliary body, both of which are heavily involved in immune signalling. In teenagers this used to be a very rare event, but it rises sharply after the Covid era begins. Post viral immune activation is the most likely driver.

And that's half way through... see you tomorrow for more.