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PRE-OPERATIVE EVALUATION IN CATARACT SURGERY
1. Chairman
Prof. Golam Mostafa
Director cum Professor , NIO&H
Moderator
Dr. S. M. Enamul Haque
Assistant Professor
Department of Cornea, NIO&H
Presenter
Dr. S.M. Hasanuzzaman
FCPS part 2 Student ,NIO&H
2. What is cataract?
Cataract comes from Latin cataracta, meaning
waterfall.
Any opacity in the lens or its capsule is called cataract.
Cataract may be-
1. Nuclear
2.Cortical
3.Subcapsular
4.Polar
4. Epidemiology
Cataract is the leading cause of vision loss.
Most common surgery performed on an outpatient
basis.
WHO estimated cataract solely causes 48% blindness
worldwide
3 million cataract surgery performed annually in USA
Direct medical cost related to the treatment of cataract
is approximately 6.8 billion USD annually(our total
budget is 67 billion USD)
8. Vision:
Decreased visual acuity:
Patients tell the ophthalmologists
Others deny: until demonstrated by ophthalmologist
Different types of cataract may have different effect on
visual acuity
PSC :Greatly impaired near vision
Nuclear cataract : myopic shift (patient experience
second sight)
Cortical cataract: Hyperopic shift
9. Glare and contrast Sensitivity:
Glare: patient often report an increase glare
In the day time
Headlights from on coming cars due to
1. PSC
2.Anterior cortical cataract
Contrast: The ability to detect subtle variations in shading
A significant loss in contrast sensitivity may occur without a
similar loss in visual acuity.
Poor night vision
10.
11. Monocular Diplopia or Polyopia
Nuclear change in the inner layer of lens nucleus
resulting in multiple refractile area that causes
monocular diplopia or polyopia.
12. Characteristics and Effect of
Cataract:
Type Growth
rate
glare Effect on
distance
Effect on
near
Induced
Myopia
Cortical Moderate Moderate Mild Mild none
Nuclear Slow Mild Moderate None Moderate
PSC Rapid Marked Mild Marked None
13. Pertinent Ocular History:
Ophthalmologists should identify conditions that
could affect surgical approach and visual prognosis:-
Trauma
Inflammation
Amblyopia
Glaucoma
Optic nerve anomaly
Retinal disease
14. Medical History:
Complete medical history is the starting point for pre-
operative evaluation
Patient should achieve optimum management of all
medical illness specially
Diabetes
Hypertension
Ischemic heart disease
COPD
Asthma
Bleeding disorder
Epilepsy etc.
15. Drug History
Systemic α1 adrenergic antagonist medications
(prazosin ,terazosin, doxazosin, alfuzosin,
tamsulosin):
For the treatment of BEP, hypertension, urinary
incontinence
Strongly associated with intra operative floppy iris
syndrome(IFIS)
Anti platelet and anti coagulant:
Low risk of hemorrhage in topical anesthesia and clear
corneal incision
16. History of Allergy:
Inquire about and document any allergies, adverse
reaction and sensitivity to:-
Anesthetics
Sulfonamide and other antibiotics
Povidone iodine and
Latex
17. Others:
Factors limiting patients ability to cooperate or lie
comfortably on the operating room table:-
Deafness
Language barrier
Dementia
Claustrophobia
Restless leg syndrome
Head tremor
Musculoskeletal disorder
18. Social History:
Surgeon should aware of patients:-
Occupation
Hobby
Lifestyle
Decision of cataract surgery is not only based on
patients visual acuity but also on the ramification of
reduced vision on individuals quality of life
19. Past records:
If patient has had cataract surgery in the fellow eye it is
important to obtain information about operative and
post operative courses :
IFIS
Elevated IOP
Vitreous loss
Cystoid macular edema
Endophthalmitis
Hemorrhage
Refractive surprise
23. Abnormality in the external eye like
Prominent eye brow,
Enophthalmos :
may affect surgical approach
Entropion
Ectropion
Eyelid closure abnormality :
may have impact on ocular surface and
adversely effect post operative recovery
24. Severe blepharitis
Acne rosacea :
risk of endophthalmitis and should be treated
before cataract surgery
Active nasolacrimal disease :
should be treated particularly if there is history
of inflammation,infection or obstruction
We simply can do a regurgitation test
25. Measurement of visual function:
Visual Acuity: Distance and near visual acuity must be
tested and careful refraction should be done so that
BCVA can be determined.
Glare testing:
Brightness acuity tester
Miller walder glare testing device
Snellen chart
Contrast sensitivity : Pelli- Robson Test
Confrontation test
27. Motility Test:
Ocular alignment should be evaluated by Hirschberg
reflex.
Range of movement of extraocular muscle should be
examined by
version and duction test
If there is any documented muscle deviation
cover and uncover test
Abnormal motility may suggest pre-existing
strabismus with amblyopia as a cause of vision loss.
28. Pupil:
Check light reflex
Direct and consensual
If there is any abnormality
Swinging Flashlight test
to detect a relative afferent pupillary defect which indicate
extensive retinal disease or optic nerve dysfuction.
Size of pupil under different lighting condition may
affect the selection of IOL.
30. Conjunctiva:
Vascularization or scarring due to previous
Inflammation
Injury
Ocular surgery may compromise healing
Symblepharon may be associated with underlying
ocular and systemic disease
Infection process should receive appropriate treatment
before cataract surgery.
31. Cornea:
Ocular surface is the principle refractive interface of
the eye.
Diagnosis and management of keratitis sicca ,
blepharitis is critical.
Scarring with history of herpetic eye disease
Assessment of corneal thickness is important
Specular reflection –endothelial cell count and cell
morphology
Vascularization , any kind of opacity that may block
surgeons view
32. Anterior Chamber :
Depth of AC aids surgical planning
Shallow anterior chamber may indicate
Narrow angle ,
Nanophthalmos,
Short axial length ,
Intumescent cataract,
Weak lens zonules
Gonioscopy is essential to rule out angle abnormality
33. Iris:
Presence of iridodonesis indicates weakened zonular
attachment
Iris coloboma may associated with lens coloboma and
localized absence of zonular attachment
Posterior synechiae due to prior uveitis makes surgery
more challenging
34. Crystaline Lens:
Careful assessment of lenticular opacity and co-
relation of degree of vision loss is important
Position of the lens and integrity of zonular fiber is
essential
Grading of Nuclear sclerosis should be done:
35. LOCS III:
Consists of three sets of standardized photographs
Evaluates four features:
Nuclear opalescence(NO)
Nuclear color(NC)
Cortical cataract(C)
Posterior Sub-capsular cataract(P)
Incorporating LOCS III allows better clinical
documentation and decrease subjective influence
38. Ophthalmoscopy:
Full fundus examination to evaluate
Macula
Optic nerve
Vitreous
Retinal vessel
Retinal periphery
Further adjunctive test may be needed in patient with DM
Assess the optic nerve (optic nerve cupping and pallor,
measurement of IOP, VA, Confrontation test and pupillary
examination)
39. Fundus evaluation in Opaque
media:
B scan ultrasonography of the posterior segment is
useful
RD, vitreous opacity, posterior staphyloma
Light projection
Two point discrimination
Maddox rod test
Blue light entroscopy
43. Biometry:
To calculate lens power result in desired post operative
refractive outcome
Two parameters:
Keratometry
Axial length
44. Keratometry: Determines the curvature of anterior
corneal surface
A scan ultrasonography:
Direct contact
Immersion method
Optical coherence biometry: Utilize two coaxial
partially coherent low energy laser beam
45. IOL Power Calculation
Formulas are used for calculating appropriate IOL
power
Popular 3rd generation formula includes Hoffer Q,
Holladay 1,Haigis L, SRK/T
4th generation formulas like Holladay2, Berret, Olsen
utilize additional measurements to refine refractive
results
46. Refractive surprise:
A refractive surprise is failure to achieve post operative
refractive target
Source of error
Prior keratorefractive surgery
Contact lens related corneal warpage
Dry eye
Silicon oil in the vitreous
Inaccurate biometry
Wrong IOL selection
47. Corneal topography:
Topography provides map of the corneal contour
Types :
Placido disc based topography
Scheimpflug imaging
Useful for
Irregular astigmatism
Patient previously undergone refractive surgery
Posterior corneal astigmatism
Patient desires a toric lens
48. Additional information of cornea:
Corneal pachymetry: Corneal thickness assessing
function of endothelium
Specular microscopy:
<1500 cells/mm2 may increase the risk of corneal
decompensation
50. Special Situation(Uveitis)
Active uveitis should be controlled before surgery
Otherwise postoperative complications like
Macular edema
Posterior synechiae
Eye should quite without topical steriod for at least 3
months before surgery
51. Special Situation(Glaucoma):
Optimum control of intraocular pressure should be
achieved prior to cataract surgery.
If this cannot be achieved surgeon may consider a
combined operation( cataract surgery along with
intervention to lower IOP)
52. Special Situation(Retinal Disease)
A family history of retinal detachment or any retinal
pathology in either of the patients eye is a risk factor
for post operative RD.
Previous vitrectomy may cause intraoperative
chamber fluctuation which increase risk of posterior
capsule disruption
53. Special Situation(Refractive
Surgery):
Refractive surgery only modify anterior corneal curvature
thereby altering normal anterior/ posterior curvature ratio
True corneal power can be measured by
Orbscan
Pentacam
OCT
IOL power formula for post refractive surgery:
Double K formula
Hoffer Q fomula
Haigis L formula:Incorporated in IOL master
Masket formula
54. Take Home Message:
Before operation ophthalmologists should assess two
things
Degree to which lens opacity affects vision
Whether surgery will improve patients quality of life
Most importantly both physician and patient should
be satisfied that surgery is appropriate choice for
improving vision