Mr Imran RahmanConsultant OphthalmologistSpecial interests:

Cataract, Corneal Transplantation and Glaucoma

Cataracts

Truth and Myths

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 A-

constant 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