What is the cornea?
cornea is the 'window' of your eye. It is the clear glass-like front.
What is the herpes
herpes simplex virus is very common. Most people have a herpetic infection
at some time of their lives. However, only in a few unlucky people does
the virus affect the cornea.
No one knows why some people develop corneal
infections not others. It has nothing to do with sex ...that is a different
type of herpes virus.
What are dendritic
virus causes a special type of corneal ulcer, called 'dendritic' (after
the latin term that means 'many fingered').
A dendritic ulcer has many
'fingers', like the branch of a tree. It can be seen with the slit lamp
microscope used to examine your eye. Fluorescent yellow drops are used
to show the ulcer up more easily.
dendritic ulcer: as seen by your doctor
dendritic ulcer: side view
do you feel?
the cornea has many nerves it feels pain easily. Dendritic corneal ulcers are
painful; your eye feels as though something is scratching it. Sunlight and bright lights
feel painful also. As the ulcer is like 'paint
on a window' your sight may be blurred.
treatment: acyclovir or increasingly Ganciclovir cream
treatment is Ganciclovir 5 times a day till healed, then one drop 3 times a day for 1 week. With prompt treatment you get a 100%
Sometimes you get a faint scar, although this is more likely
without treatment. Use
aciclovir ointment, not the skin cream. Bring it to clinic each visit,
with all your other drops and list of tablets you use. It is very safe. Use about 2cm length of cream
5 times a day at the beginning, but later in the episode as your eye heals
you need less (5-10mm), although you may still need it 5 times a day. Longer treatment is needed if you are immunosuppressed.
Just at present in the UK Aciclovir is not currently available, and ganciclovir cream is used instead. Indeed, ganciclovir is active against CMV, which may be an alternative cause of the 'disciform' or stromal keratitis described on this page.
A typical dendritic ulcer: no need to review patient.
If the symptoms have lasted more than more than 1 week, and in larger, peripheral ulcers, a PCR can be helpful to identify the virus.
If the ulcer persists, there may be a neurotrophic problem.
but can be treated with Aciclovir 800mg 5 times aday and foscarnet, but these are VERY rarely needed.
can you treat yourself?
ulcers may recur. It is certainly helpful to keep a tube of unopened
ointment with you, especially on holiday. If you do develop another episode
it is quite safe to start treatment. (Aciclovir is safe even if you are
mistaken and there is no infection.)
Use the aciclovir, following typical
instructions as above. Most doctors advise you attend
an Eye Casualty, such as that in Birmingham and Midland Eye Centre on
the City Hospital site (Dudley Road), that day or the next. Treatment is not so urgent
as to need to attend late in the evening or the middle of the night.
Like any infection, stress,
overwork, or lack of sleep can trigger a recurrence. Dendritic ulcers
can be triggered by sunlight. Dark glasses may help prevent a recurrence,
and they certainly help during an attack. If you develop frequent episodes,
ask your doctor if long term aciclovir cream or tablets may be helpful
can be prevented
is now conclusive evidence that attacks can be prevented with the
use of aciclovir, see here
(2003). Treatment may be needed for 2-3 years.
- this evidence indicates using aciclovir tablets
400mg twice daily will halve the number of attacks
- if you have frequent attacks, you should ask your
doctor to consider this treatment; it is usually very safe
- what are frequent attacks: probably more than
one a year
- if you have one attack a year normally you will
probably still benefit
- the more severe your attacks, the more you will
benefit; if the condition affects the centre of your cornea, prevention
is more important
- Aciclovir cream
may prevent recurrences, but is not as effective as tablets. Use
if patient unwell (other medical problems) instead of tablets
- Aciclovir is
generally safe for long term use but rarely causes crystals in the
kidneys. As a precaution it is important to drink plenty of fluids,
and it is not ideal long-term if kidney function is reduced.
- Vitamin D has helped some patients
- Many patients notice a reuccurence without continuing a steroid drop. But often only a low does of steroid, such as FML once a day or even lsess often, will be effective.
- Use prophylaxis in cataract and corneal graft surgery (ganciclovir with the post-op steroids in cataract surgery).
- A flu vaccine can cause reactivation (prophylaxis should prevent this).
Corneal endothelialitis (probably cytomegalovirus cytomegalovirus), previously termed, 'Stromal'
or 'disciform' keratitis
Corneal endothelialitis (disciform keratitis) is a deeper infection the cornea
(deeper than the dendritic ulcer above)
the infection is in the substance of the cornea the condition is called corneal endothelialitis or 'stromal keratitis' or 'disciform keratitis' or 'herpetic' keratitis'.
Treatment: Ganciclovir 5 times a day till healed, then one drop 3 times a day for 1 week.
This condition is now thought to be due to either the cytomegalovirus or the herpes simplex virus, but the treatment is the same.
Early routine cases usually do not need steroid drops, but sometimes low dose steroid drops
may be needed (such as predsol), but only under close ophthalmological
If you need steroid drops for one episode you may also need them for future
Stromal keratitis attacks may
recur frequently. If they do, preventative treatment may work. Aciclovir
tablets 400mg once or twice a day halves
the number of episodes, but
may be needed for a year or two. If aciclovir tablets cause side effects, use Ganciclovir 1-2 times a day long term.
Disciform keratitis may be due to cmv, and is now termed corneal endothelialitis BJO 14 (cytomegalovirus corneal endothelialitis). Ganciclovir is the best treatment.
- PCR test
- treatment BJO 17
- those +ve for cmv
- coin shaped lesion, corneal oedema
- 10% ..linear
In disciform keratitis the central cornea is cloudy/opaque.
Also, a semi-opaque scar may remain after the infection itself has cleared.
Professionals: steroid drops in herpetic keratitis etc
patients with delayed healing dendritic ulcers may need a different antiviral,
but resistance is very rare and this is not usually necessary.
steroid drops are needed. Stromal keratitis will need steroid drops at
- always test for sensation
- if a person needs
steroid drops to heal their ulcer, then if they get further episodes,
steroids will be needed again
- it is best to taper
the steroids after the attack, continuing them well after the ulcer
has healed. Often drops will be needed for 6-12 months
- treatment starts
will full strength drops (prednisolone 0.5%), but then reduced each
month, to prednisolone 0.1% (or 0.5% every other day if not available),
then ideally to 0.01%, over this 6-12 month period
are needed in addition to the steroid until the 0.01% dilution is
some infections become resistant to Aciclovir...
- if any uveitis Aciclovir 4-800mg five times day, no steroid if possible, not safe for 10 days
- some patients need on-going treatment with low dose topical steroids,
such as prednisolone 0.05 or 0.1%. If these are not available, may
be alternate day treatment of 0.5% may help.
- 20% of apparent HSV keratitis is HZV
- generally dendritic ulcers (epithelial disease only) do not need treatment with steroids