Phacoemulsification some Basic Ideas…

1. Khalid M. Al-Arfaj, MD Phacoemulsification some Basic Ideas… Dammam University

2. 1-Quiz … 2- lecture … 3-Vedio …

3. Case selection … • Anesthesia…

4. Pre-operative Eyedrops • Antibiotics • Control blepharitis well before surgery (endophthalmitis usually results from lid flora)! • Fluoroquinolones • Povidone-iodine • inexpensive • extremely broad-spectrum • irritating to eye in undiluted (10%) solution; dilute to 5% • irrigate fornices with solution • paint, do not scrub, eyelashes when prepping

5. History of small incisions • 1977: Scleral tunnel • 1990: Sclerocorneal • 1991: Clear corneal • 1991-present: Variations in clear corneal

6. Conjunctival peritomy • Dissection through Tenon’s fascia • Cautery • Scleral groove 1-2 mm posterior to the limbus • Scleral tunnel • Keratome to enter the AC

7. Advantages: • Wound can be safely enlarged for conversion to ECCE • Conjunctiva covers the wound • Potentially less endothelial damage • Astigmatically neutral

8. Disdvantages: • Surgical exposure • Sunken eyeball • Prominent brow • Potential damage to ciliary body • Iris prolapse • Filtering blebs and scarring make it difficult

9. Clear cornea • Keratome to tunnel and enter the eye .

10. Advantages: • Can use topical anesthesia • Faster • Better surgical exposure • Filtering blebs and scarring irrelevant • No subconjunctival hemorrhages

11. Disadvantages: • Pre-existing corneal problems a relative contraindication: • Fuchs • Previous PK • Possible higher rate of endophthalmitis in unsutured cases • Ballooning of conjunctiva if incision too posterior • Conversion to ECCE more problematic

12. Wound location • Astigmatism • Pre-existing ocular disease: • Pterygia • Filtering blebs • Tubes • Endothelial disease

13. Wound architecture • Tunnel length • Goal to be self-sealing • “Square” incision • Depends on width • Generally want at least 2.0-2.5 mm long • Sharp entry through Descemet’s membrane

14. Problems with the wound • External incision • Too anterior or too posterior • Internal incision • Too anterior or too posterior • Tunnel • Too long or too short • Incision width • Too narrow or too wide

16. Wound Final Thoughts • The wound may be one of the easiest steps of cataract surgery, but it sets the stage for the entire case • Everyone may have a different phaco wound • Principles the same

17. Capsulorrhexis • Continuous curvilinear capsulorrhexis (CCC) • It is a continuous tear capsulotomy. • It can be made in the anterior capsule or both anterior and posterior capsules. • It confines the IOL to the capsular bag. • It assures long-term centration of the IOL.

18. Technique • Completely fill the anterior chamber with viscoelastic agent. • Flatten the dome of the anterior lens capsule • Puncture the anterior capsule with a bent 30-gauge needle or sharp-tipped capsulorhexis forceps. • Start a flap that flops over toward the incision.

19. Technique • Grasp the flap with capsulorrhexis forceps (Utrata forceps). • Spiral out to the desired diameter. • Tear tangentially all the way around (no radial forces). • Regrasp the flap as necessary. • Keep an equal distance from the pupil margin while tearing.

20. Hydrodissection & Hydrodelineation • Goals • Nucleus rotation • Epinucleus rotation • Loosen cortex

21. Hydrodissection • Used to separate lens nucleus from surrounding cortex and capsule • Creates a freely mobile nucleus • Facilitates nucleus rotation during phacoemulsification

22. Hydrodelineation • Used to separate epinucleus from harder nuclear material • Creates an epinuclear bowl that protects lens capsule during phacoemulsification

23. Technique … Background • Hydrodissection cannula • 25- to 30- gauge • Flattened tip with angled or curved shaft • Facilitates placement under anterior capsule • J-shaped cannula may be used for sub-incisional area

24. Complete several fluid waves to ensure adhesions to capsule broken • Proceed to hydrodelineation • Inject fluid into edge of nucleus • “Golden ring” sign indicates epinuclear separation • Confirm that nucleus rotates

25. Intraoperative Capsular Block Syndrome • Lens nucleus occludes capsulorhexis • Trapped BSS expands posterior capsule, AC shallows • Posterior capsule may rupture

26. PHACODYNAMICS

27. Two Basic Elements • US → Emulsify the Cataract • Fluid circuit → cooling and remove the Emulsified Cataract

28. Three Main Machine Functions • US • Flow • Irrigation

29. Fluidics • Irrigation • Flow • Vacuum

30. Type of Pumps Fluidics • Flow → peristaltic → vacuum only at occlusion • Vacuum → venture → continuous vacum • BOTH → millennium Flow control mode Vacuum control mode

31. Irrigation • Amount of fluid that enters the eye Depend on: • Bottle height • pressure on the eye • flow from the eye • Tip diameter • Wound leak

32. Flow • Fluid leaving the eye ml/min • Speed with which the material is sucked to the tip • Control pump speed • No-occlusion → current and attraction force • With occlusion → rise time (time for maximum preset vacum) • Flow rate • Surge • Vacum rise • Safety

33. Vacuum • Holding power With occlusion → No flow but pump will continue → negative pressure at aspiration line → vacum → Stop pump at maximum preset vacum

34. Good Fluidics Irrigation Wound Leak • Aspiration (flow) • Vacum

36. Surge • Sudden ↓ of A/C pressure → collapse • Dynamic ↓ of vacum by surgeon by deocclusion • Bottle height • Machine compliance • Vacum and flow rate • Tip diameter → resistance

37. Flow Flow depends on pump speed not on bottle height

38. US • Power • mode of delivery

40. US • Safest phaco is with appropriate power not with the lower power

41. Mechanism of Action • Jackhammer → direct contact • Cavitation → with cavitational bubbles • Sonic wave

42. Mode = US Delivery • Continuous • Pulse • Burst

43. Pulse • Fixed interval but linear power • Fixed duty cycle

45. Burst Mode • Fixed power of linear interval • Variable duty cycle

48. Repulsion Chatter → flaying of peace away from the PHACO tip • Mode - ↓ by Pulse , Burst and WS