Transcript Managing Electronic Documents Effectively

Cataracts
Truth and Myths
Mr Imran Rahman
Consultant Ophthalmologist
Special interests:
Cataract, Corneal Transplantation and Glaucoma
What is a cataract?
• Latin word for waterfall
What is a cataract?
What is a cataract?
The History of Cataract Surgery
• Reports of cataract surgery date back 300BC
• ConstantinusAfricanus (AD 1018)
– Cataract
• Couching 600BC in India:
– Aphakic correction
– Remained popular until 19th century
Scale of the problem
• 18 million people blind with cataracts
• 2 million procedures in the US
• Over 300000 in the UK last year
• Over last 20 years, number of procedures
quadrupled
Age and risk factors
• 42% between 52-64,
• 60% between 65-74
• 91% between 75-85
•
•
•
•
•
UV exposure: 3 xs more prevalent in pilots
Diabetes
Trauma
Genetics
Medicines
Prevention
• UV glasses more delay onset
• Vitamin A,C and E
• N-acetylcarnosine can treat cataracts??
• Realistically no true prevention
Symptoms of cataract
•
•
•
•
•
•
•
Individual
Second sight
Blurring
Loss of sight
Glare
Daily tasks difficult
Falls and secondary injuries
Glare and clarity
What we do about cataracts?
• Remove only when vision affected or retinal
problems
• Removal and replacement of cataract lens
has been mastered
• Results exceptional
• But expectations increased
Cataracts
• Removal and replacement of vision has been
mastered
• Results exceptional
• But expectations increased
Intracapsular and extracapsular
surgery
• Intracapsular surgery with Cryoprobe
– Aphakic
– AC lens
• Extracapsular surgery started 1753
– Jacques Daviel long corneal incision
– Von Graefe 1865 small scleral incision
– Intracaps favoured
Phacoemulsification
• Charles Kelman 1967
– 4 hours and 41 minutes of ultrasound
– Endophthalmitis
• Phacoemulsification took off some 20 years
later
• Average time for surgery is 15 mins
• Incision size decreased from 12mm to 3mm
and now possible through 1.8mm
Introduction of the IOL
• Operating microscope 1948
• Intraocular lens 1948
– Harold Ridley 1906-2001
– Perspex
– Opposition
• ECCE became favoured procedure
Current IOL outcomes
• 80% within +/- 1 D of desired outcome
• Monofocals
• Why?
Limitations of current IOL
measurements
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
No matter how good the system, people will still make mistakes. Some reasons include:
people in a hurry
lack of training or accessible guidelines
reliance on others
technical failure (rarely)
human error (often).
Some common mistakes (collected from the UK and overseas departments):
wrong A-constant selected
wrong formula used
wrong K-readings entered by hand (90 degrees out)
biometry print-out stuck in wrong patient’s notes
incorrectly labelled IOL
wrong patient in theatre
reversed IOL optic
wrong IOL implanted (25.5 D implanted instead of 22.5 D or +30 D instead of +3.0 D).
Some errors of omission include:
no biometry at all
no spectacle prescription or focimetry available
no IOL available on the day
not taking account of the other eye
not discussing the intended outcome with the patient.
Another factor to consider is the postoperative position of the IOL. Inadvertent placement in the sulcus will cause a 0.75 D myopic shift. If an anterior chamber IOL has to be used, the Aconstant will be different. If all else fails, blame the machine! Different biometry machines may give different results, which can be confusing (e.g. A-scan biometry and IOL Master).
In some high-volume clinics, the time required for biometry exceeds the time taken for surgery. However, if you are going to do biometry, you have to do it properly and thoroughly. It is
better to have a few well-trained and experienced members of staff who can get consistent results, than to have many people with limited training and experience.
Departments should aim for consistency in their biometry and audit their results. Mistakes are easy to make, but difficult (and sometimes expensive) to rectify. The following list sums up
some lessons that can be learnt from others’ mistakes:
slow down
train and certify your biometry staff
follow guidelines
don’t rely on others
watch out for the unexpected
learn from mistakes, particularly any eyes with error greater than 2 dioptre
audit your outcomes.
If you are using biometry, 80 per cent of eyes should be within 1 dioptre of their intended refraction. Try to identify any issues that are leading to consistent errors
Complications
•
•
•
•
•
•
Unusual
Infection
Bleeding
Irritation
Retinal detachment
Sight loss
Presbyopia
• Holy Grail
• An unwelcome reminder of advancing age
• Mechanism unknown
Signs of Presbyopia
• Loss of ability to read up close
• Difficulty reading in bright light
• Difficulty viewing a computer
screen
• Need reading glasses or bifocals
• Holding objects further away to
read
Prelex and Premium lenses
• The hope of premium lenses
• Choosing the right lens for the right patient
• Hypermetropes are desperate to revert to
spectacle independence
Prelex and Premium lenses
• The hope of premium lenses
• Choosing the right lens for the right patient
• Hypermetropes are desperate to revert to
spectacle independence
Acri:Lisa
• Acrilisa stated as 90% spectacle
Independence
• Only 1 year old
• Yet to be proven
Crystalens AO
International
Registry
Always
Sometimes
Never
Distance
6%
13%
81%
Near
6%
34%
59%
Never for
distance or
near
-
-
47%
Restor and Tecnis
• 80% of patients no longer needed glasses or
contact lenses to see clearly at all distances
Limitations
•
•
•
•
•
Studies look at spectacle independence
Image quality limited
Sharpness reduced
Haloes and glare
Decrease vision in dim light
Light Adjustable Lens
•
•
•
•
•
Only lens adjustable after implantation
Perfect ‘guaranteed’ vision can be achieved
Stable
Corrects presbyopia and cataract
This is the next big innovation in Lens
surgery
• The Future of Intraocular lenses
Customisation
The next Members Health
Seminar is on:Wednesday 8th September 2010
10.30 – 11.30am
Education Centre Lecture Theatre
VISION – Mr Phil Graham