Assessment & management of patients with cataract

1. Assessment & management Assessment & management
of patients with cataractof patients with cataract

2. Prevalence & morphologyPrevalence & morphology
Cataract with VA < 6/9: 5% in 55-64 age group,
40% in 75+ age group.
Three major types:
cortical (~60%)
nuclear (~40%)
PSC (~20%)
•Some have mixed cataract. Early nuclear changes
tend to be called normal age changes rather than
cataract.

5. Cortical
· most prevalent accounts for 63%
of cases
· wedge shaped opacities found in
anterior and/or cortical posterior
lens cortex
· opacification due to light scatter
· found in the infero-nasal portion
of lens

7. Nuclear
· accounts for 41% of cases
· homogenous ­ in light scatter
in the lens nucleus
· can be associated with lens
yellowing

9. Posterior Sub-Capsular (PSC)
· accounts for 24% of cases
· occur at back of lens in front
of the posterior capsule
· localised ¯ in refractive index
and accompanying vacuole
formation
· centrally positioned

10. Vision loss in cataractVision loss in cataract
Could be caused by:
increasing myopia and astigmatism,
monocular diplopia,
reduced light transmission
changes in colour perception
Mainly due to increased light scatter, and
changes in pupil size.

11. Case HistoryCase History
Guidelines have suggested the following indications
for cataract surgery:
·Visual acuity (VA) is 6/15 or worse and is solely due
to cataract.
·The patient decides that the expected improvement
in function outweighs the potential risk, cost and
inconvenience of surgery after being given
appropriate information
·The patient's ability to function in their desired
lifestyle is reduced due to poor vision.

13. Binocular visionBinocular vision
Be wary of monocular diplopia, caused by
acute refractive index changes.
Can decrease or increase with
progression.
? block second image with black strip.
Make sure not due to uncorrected
astigmatism, likely in cortical cataract.

14. Objective refractionObjective refraction
Difficult due to reduction in light returning.
ARs tend not to be able to provide a result.
Use radical retinoscopy (move closer,
careful with distance as inc. risk of error,
no difference to error in astigmatism).
Use as few lenses as possible (each one
loses you 8% of light via reflections).

16. Subjective refractionSubjective refraction..
JND is larger, therefore use ±0.50D or
more.
JCC should be ±0.50, ±0.75 or ±1.00 DC.
Look for increased minus with nuclear
cataract.
Look for increased/ changes in
astigmatism with cortical cataract.

17. Clinical vision testsClinical vision tests
Although referral is based on case history and
Px’s symptoms, it should be justified by
reduced vision on one or more clinical tests.
i.e. the surgery should be able to return vision
on these tests to normal values. This will
hopefully resolve the Px’s symptoms.

18. Visual acuity (VA)Visual acuity (VA)
Distance VA is the traditional clinical test.
Provides a reasonable assessment of
vision in the real world in many cases (but
not all).
Best measured with a logMAR chart.
Near VA can provide useful information,
especially with PSC cataracts.

19. logMAR chart

20. · contrast sensitivity at low to intermediate
frequencies is ¯ in cataract Pxs
· surgery can return these values to age-matched
normal values
· the best available test for use is the Pelli-Robson
chart
· Pxs with contrast sensitivity £1.35 are likely to
complain of poor vision
Contrast sensitivity (CS)Contrast sensitivity (CS)

21. Pelli-Robson CS chart

22. Contrast sensitivity (CS)Contrast sensitivity (CS)
See Clinical Optometry II notes.
·Mrs. D.H.: Homemaker, age 68 years, with extensive
cortical cataract R & L and Sxs of great difficulty
recognising friends, reading and knitting, with much
worse vision in bright sunlight.
·VAs: R: 6/6, L: 6/7.5. Reduced Pelli-Robson CS (1.05
and 1.35 log) provided justification for surgery. The
right cataract was extracted (the eye with the better
VA but the worst CS) and this provided significant
improvement in visual ability.

23. Disability Glare & Colour Disability Glare & Colour
VisionVision
See Clinical Optometry II notes.
 NB for glare: case record of Rubin (1972).
NB for colour: Monet.
Note that Ishihara only assesses Red-green
problems.
Note that diabetics as well as getting colour
problems due to retinal changes, also get
cataract earlier.

24. Brightness Acuity Tester

25. Stereopsis and Visual fieldsStereopsis and Visual fields
Poor stereopsis can be useful when referring
2nd eye cataract patients.
Cataract causes problems of interpretation of
fields in glaucoma and may be removed to
aid treatment in diabetics.
Localised opacities tend not to cause
localised fields, but can alter mean sensitivity
and the pattern (CPSD).

26. Slit-lamp biomicroscopySlit-lamp biomicroscopy
Assesses backscatter.
Nuclear - optic section.
Cortical and PSC - retro-illumination (direct
ophthalmoscope is good).
Draw PSC and cortical. Can get classification
systems to accurately grade.
Check corneal endothelium.

29. Fundus examinationFundus examination
Co-morbid disease is the biggest cause of
“unsuccessful” surgery.
Use Volk: Far, far better view through cataract
than direct (dilated or not).
Also get 3-D view and better FOV.
May need to dilate.
Refer Pxs with ARMD etc. if have moderate/
dense cataract.

30. Potential Vision TestsPotential Vision Tests
Simple indicators: age, diabetes,
hypertension, macular disease in other eye.
Swinging flashlight test.
? PAM, ? Retinometer.
Best future test? The Bradford Reading
speed test!

31. Management of patients with Management of patients with
cataractcataract
Referral: see previous guidelines.
Latham & Misson study (1997):
Optometrists: 6/18;
Ophthalmologists: 6/9
but Optometrists refer too early (??!!).
Referral letters: indicate the patient’s problems
(basis for referral) and then clinical test results
(justification).

32. Counselling Counselling
“Have I got cataract?”
Use clinical definition. Always then describe
cataract (not “skin over eyes”) and explain
how good modern surgery is.
If lens opacity is not affecting vision, you
could say they have an age change in the
lens that could turn into a cataract later.
Inform Px if they have a PSC.

33. CounsellingCounselling
“Can I drive?”
Cataract Pxs may have 6/9+ VA in your exam
room, but see little when night driving or
driving on a sunny day (use glare test).
Document advice and perhaps inform GP.
Pxs may consider this advice when deciding
whether to be referred for surgery.

34. Prognosis and follow-upPrognosis and follow-up
Cortical and nuclear tend to be slowly
progessive: 5-10 years after first noted.
Lens opacity: 2 year follow-up.
Cataract: 1 year follow-up
Cataract-induced myopia or astigmatism that is
quickly progressing, some patients with PSC or
other rapidly progressing cataract: 3 or 6 months.

35. Removal of risk factorsRemoval of risk factors
Stop / reduce cigarette smoking.
Use UV blockers.
Use anti-oxidant vitamins (C,E, beta-carotene).

36. CounsellingCounselling
“Use up my eyes”: advise Pxs that
longevity of sight cannot be ensured by
small daily use of the eyes (like
withdrawals from a bank).
Typoscopes: great for improving
reading in cataract.