pre and post-operative management of cataract surgery

∗Pre and Post Operative Management of Cataract Surgery

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Pabita DhungelB.Optometry

1. American Academy of Ophthalmology (section - 11 Lens & Cataract)

2. Clinical Ophthalmology (Kanski fouth edition)3. Clinical Ophthalmology (Myron Yanoff)4. Oxford hand book of ophthalmology (second

edition)5. Cataract surgery and its complications (6th

edition, N.JAFFE, M. JAFFE, G.JAFFE)

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References

∗ Introduction to cataract∗ Introduction to cataract surgery∗ Preoperative management∗ Post- operative management∗ Summary

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Presentation Layout

∗ Cataract derives from the Latin word ‘cataracta’ meaning "waterfall“

∗ Any opacity in the human crystalline lens that causes it to loose it’s transparency and /or scatter light compromising the visual acuity

∗ Any opacification of IOL after cataract surgery is known as after cataract

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Introduction

∗ It is estimated around 20 million people are blind due to this disease

∗ Estimated 50 million people blind due to cataract by 2020

∗ By the year 2020, the final target should be 32 million cataract surgeries annually

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Global Cataract Blindness:

According to Nepal Blindness Survey(1980-1981):• A. Cataract and its sequelae(72%)• B. Trachoma• C. Ocular infections• D. Xerophthalmia• E. Glaucoma

• According to study “Prevalence of blindness and cataract surgery in Gandaki Zone, Nepal” cause of blindness due to cataract was found to be 60.5%

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Cataract Blindness in Nepal:

∗ Common indication* Loss of stereopsis* Decrease of peripheral vision* Bothersome glare* Symptomatic anisometropia

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INDICATION FOR CATARACT SURGERY

∗ Medical indication* Phacolytic glaucoma (mature,hypermature cataract)* Phacoantigenic uveitis (traumatic cataract)* Phacomorphic glaucoma (intumescent cataractous lens)* Dislocation of lens into AC* Lenticular tumor: Epithelioma, epitheliocarcinoma.* Dense cataracts

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Contd…

∗ Patients with significant cataracts∗ Patients decide to seek of visual function through

cataract surgery.∗ Cosmetic indication: Mature cataract in the blind

eye (for restore the black pupil only)∗ May require cataract surgery:

* Posterior subcapsular cataracts (near VA < N8 even though far VA still 6/12).* Nuclear cataracts that far VA 6/18 even though near VA still N5.

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Contd…

∗ GENERAL HEALTH* Diabetes mellitus* Ischemic heart disease* Smoking* HTN* Chronic obstructive pulmonary disease* Bleeding disorder* Drug sensitivities & medications: immunosuppressant or anticoagulant…

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Pre operative evaluation

PERTINENT OCULAR HISTORY

* H/o of trauma* Inflammation* Amblyopia* Glaucoma* H/o has already had cataract extraction (compl: vitreous loss….)

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* Look for abnormalities of external eyes and adnexa:. Blepharitis. Entropion, ectropion. Decrease of corneal sensation. Abnormal tear function, Exposure keratitis. Dacryocystitis. Other condition: head tremor…

* Motility: EOM, Cover test, Strabismus + Amblyopia..* Pupil: Reacting to light…RAPD (+/-)

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EXTERNAL EXAMINATION

a)- Conjunctiva:. Scarring. Symblepharon. Conjunctivitis

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SLIT-LAMP EXAMINATION

b)- Cornea:. Specular reflection with slit-lamp can estimate

the endothelium cell count and morphology.. If abnormal or C- thickness > 600 µm is poor

prognosis for corneal clarity.. Corneal dystrophy. Keratoconjunctivitis sicca

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Contd…

c)- Anterior chamber:. Shallow (intumescent of lens or forward

displacement by posterior pathology). Gonioscopy to rule out the angle abnormalities

(synechia, neovasculization).d)- Iris:

. Pupil size after dilation is noted

. Posterior or anterior synechia (+/-)

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e)- Crystalline lens:. The visual significance of oil droplet nuclear

cataracts & small posterior subcapsular cataracts are the best appropriated before dilation.

. Exfoliation syndrome is the best seen follow dilation.

. Small posterior subcapsular cataracts can cause severe visual loss

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Contd…

b)- In DM patient,we should look for: Macular edema, retinal ischemia, vitreous retinal traction, lattice degeneration, macular hole.c)- Mature cataracts, evaluated by B- Scan Ultrasonography that helpful in RD & posterior segment tumor

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FUNDUS…….

∗ a)-Visual acuity testing ( N & D)∗ b)- Brightness acuity* Pts complain of glare (should check distance & near

acuity in well lighted room with non projected or projected eye chart.

* Pts with significant cataracts show decrease VA of three or more lines under this condition

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Measurement of visual function

∗ c)- Contrast sensitivity∗ d)- Visual field testing (Goldmann & Automated)∗ e)- Color vision

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Contd…

∗ SPECIAL TESTSa)- Potential acuity estimation

• Clinical Interferometers & Potential Acuity Meter are able to measure macular acuity directly by projecting grating patterns or Snellen letter on the retina.

• This test can be misleading in present of: Age related macular degeneration, amblyopia, macular edema, glaucoma, small macular scar & serous RD.

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PREOPERATIVE EVALUATION (Cont)

b)- Testing for macular function* Maddox Rod: large scotoma (macular disease)

* Purkinje’s entoptic phenomenon ( Retina)(light shone through close eyelid…shadow).

* Two light discrimination indicates normal macular function, if two point light sources can be distinguished when held 2 inches apart & 2 feet from the eye

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Special tests

∗ REFRACTION∗ BIOMETRY (keratometry & A-Scan)

Performed to calculate the approximate IOL power implantation.Use SRK formula (Sanders, Retlaff & Kraff)P = A – 2.5L – 0.9KP : Lens implant power for emmetropia (D)L : Axial length (mm)K : Average keratometric reading (D)A : Constant specific to the lens implant to be used

That A = 113 for AC lenses & 119 for PC lenses.

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Pre operative measurement

∗ Check that biometry does indeed belong to your patient

∗ Check for intraocular consistency in axial length and K values (i.e that they are similar and the standard deviation is low)

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IOL selection

∗ Check for interocular consistency in axial length and K values

∗ If axial length difference >0.3mm confirm by B-scan and if the difference in K readings >1D then consider corneal topography

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Contd…

∗ CORNEAL PACHYMETRY* Ultrasonic pachymeters can accurately & reliably measure endothelial cell function.* If thickness > 600 µm maybe consistent with corneal edema & endothelium dysfunction that increase the likelihood postoperative clinical corneal edema.

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∗ SPECULAR MICROSCOPY: (endothelium cells)* A normal cell count > 2400 cells/mm2

* If a cell count fewer than 1000 cells/mm2 is risk of postoperative corneal decompensation.

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Contd…

∗B-Scan ultrasonographyUseful whenever it is impossible to view the retina & can determine of posterior segment with regard to the potential for:

* RD* Vitreous opacity* Posterior pole tumor

∗ Complete blood counts, Hb…∗ Blood sugar∗ Urinalysis∗ Chest X-ray

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Laboratory investigations

∗ Syringing ∗ Conjuctival swab

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Contd…

∗ Pediatric IOL: size, design and power∗ 1. Size of IOL above the age of 2 years may be

standard 12 to 12.75mm diameter for the bag implantation

∗ 2. Design of IOL recommended is one- piece PMMA with modified C- shaped haptics (preferably heparin coated)

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Pre operative management in pediatric age groups

∗ Power of IOL in children between 2-8 years of age 10% undercorrection from the calculated biometric power is recommended to counter the myopic shift

∗ Below 2 years on undercorrection by 20% is recommended

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Contd…

∗ Topical antibiotics : tobramycin, gentamycin or ciprofloxacin QID for 3 days

∗ Preparation of eye to be operated : eyelashes of upper lid should be trimmed at night

∗ An informed and detail consent should be obtained

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Preoperative medications

∗ IOP should be lowered by acetazolamide 500mg stat 2 hours before surgery and glycerol 60ml mixed with equal amount of water or lemon juice 1 hour before Sx or, IV mannitol 1gm/kg body weight half hour before Sx

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∗ To sustain dilated pupil ∗ antiprostaglandin eye drops such as indomethacin or

flurbiprofen TID 1 day prior to surgery∗ Adequate dilation also by 1% tropicamide

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∗ Patient is asked to lie quietly upon the back for 3/ 4 hours

∗ For mild to moderate post-operative pain injection diclofenac sodium may be given

∗ Next morning bandage is removed & inspected for post-op complication

∗ Antibiotic-steroid eye drops are used two hourly 1 week,QID 4 week then tapering, TID, BD and OD for each week

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Post- operative management

∗ Tear supplements are given for at least one month or more depending upon the patients complain to prevent post cataract surgery dry eyes

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Contd…

∗ Cornea: wounds sealed (Seidel test negative), clarity∗ AC: formed, activity∗ Pupil: round, regular and reacting∗ PCIOL: centred and in the bag∗ Consider : IOP checking

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Post -op examination

∗ Give clear instructions re postoperative drops∗ Use of clear shield∗ What to expect (discomfort, watering) ∗ What to worry about (increasing pain/ redness,

worsening vision)∗ Where to get help (including telephone number)

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∗ Examination ∗ VA: unaided/aided∗ Cornea: wounds sealed (Seidel test

negative), clarity∗ AC: depth and clarity∗ Pupil: round, regular and reacting

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Final review (2-4wks later)

∗ IOP∗ Fundus : no cystoid macular oedema, flat retina∗ If good result then either list for second eye (in

bilateral cases) or discharge to optometrist for refraction as appropriate

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Contd…

∗ If disappointing VA (unaided) perform refraction/autorefraction to look for ‘refractive error’ and dilated fundoscopy to check for the subtle CMO (specially if VA (pinhole) < VA (unaided)) and if in doubt, consider OCT

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Contd…

∗ In patients where the refractive outcome is harder to predict (high ametropia, previous corneal refractive surgery), review patients early (1 week) with refraction to permit the option of an early IOL exchange if a large discrepancy noticed

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Refractive surprises

∗ After 6-8 weeks of operation corneoscleral sutures are removed (when applied)

∗ Final spectacles are prescribed after about 8 weeks of operation

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Contd…

∗ Correction of paediatric aphakia∗ Children above the age of 2 years corrected by PC-IOL

during surgery∗ Children below the age of 2 years should be

preferably corrected by extended wear CL∗ Spectacles can be prescribed in B/L cases

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Postoperative management of pediatric age group

∗ Later on secondary IOL implantation may be considered

∗ Primary implantation at earliest possible (2-3 months) specially in unilateral cases

∗ Management of amblyopia in long term follow up

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Contd…

∗ Every 6 months follow up for first five years and then followed by yearly follow up

∗ Correction of refractive error as far as possible to prevent amblyopia

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Contd…

∗ Refractive error is assessed at 8th week of cataract surgery

∗ Refractive correction is prescribed only if the error persist even after three months of cataract surgery

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Management of refractive error in adults

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THANK YOU