conventional extracapsular cataract extraction| 6minutemedico скачать в хорошем качестве

conventional extracapsular cataract extraction| 6minutemedico

conventional extracapsular cataract extraction| 6minutemedico CONVENTIONAL EXTRACAPSULAR CATARACT EXTRACTION Surgical steps of conventional ECCE are: 1. Superior rectus (bridle) suture is passed to fix the eye in downward gaze (Fig. 9.23A). 2. Conjunctival flap (fornix based) is prepared to expose the limbus (Fig. 9.23B) and haemostasis is achieved by wet field cautery. Many surgeons do not make conjunctival flap. 3. Partial thickness groove or gutter is made through about two-thirds depth of anterior limbal area from 10 to 2 O’clock (120°) with the help of a razor blade knife (Fig. 9.23C). 4. Entry into anterior chamber. The anterior chamber is entered with the razor blade knife or with 3.2 mm keratome. 5. Injection of viscoelastic substance in anterior chamber. A viscoelastic substance such as 2% methylcellulose or 1 % sodium hyaluronate is injected into the anterior chamber. This maintains the anterior chamber and protects the endothelium (For details see page 458). 6. Anterior capsulotomy. It can be performed by any of the following methods: i. Can-opener’s technique. In this an irrigating cystitome (or simply a 26 gauge needle, bent at its tip) is introduced into the anterior chamber and multiple small radial cuts are made in the anterior capsule for 360° (Fig. 9.24A). ii. Linear capsulotomy (Envelope technique). Here a straight incision is made in the anterior capsule (in the upper part) from 2–10 O’ clock position. The rest of the capsulotomy is completed in the end after removal of nucleus and cortex. iii. Continuous circular capsulorrhexis (CCC). Recently, this is the most commonly performed procedure. In this the anterior capsule is torn in a circular fashion either with the help of an irrigating bent–needle cystitome or with a capsulorrhexis forceps (Fig. 9.26B). 7. Removal of anterior capsule. It is removed with the help of a Kelman-McPherson forceps (Fig. 9.24B). 8. Completion of corneoscleral section. It is completed from 10 to 2 O’clock position either with the help of corneoscleral section enlarging scissors or 5.2 mm blunt keratome (Fig. 9.24C). 9. Hydrodissection. After the anterior capsulotomy, the balanced salt solution (BSS) is injected under the peripheral part of the anterior capsule. This manoeuvre separates the corticonuclear mass from the capsule. 10. Removal of nucleus. After hydrodissection the nucleus can be removed by any of the following techniques: i. Pressure and counterpressure method. In it the posterior pressure is applied at 12 O’clock position with corneal forceps or lens spatula and the nucleus is expressed out by counterpressure exerted at 6 O’clock position with a lens hook (Fig. 9.24D). ii. Irrigating wire vectis technique. In this method, loop of an irrigating wire vectis is gently passed below the nucleus, which is then lifted out of the eye. 11. Aspiration of the cortex. The remaining cortex is aspirated out using a two-way irrigation and aspiration cannula (Fig. 9.24E). 12. Implantation of IOL. The PMMA posterior chamber IOL is implanted in the capsular bag after inflating the bag with viscoelastic substance (Figs. 9.24 G and H). 13. Closure of the incision is done by a total of 3 to 5 interrupted or continuous 10–0 nylon sutures (Fig. 9.24I). 14. Removal of viscoelastic substance. Before tying the last suture the viscoelastic material is aspirated out with 2 way cannula and anterior chamber is filled with BSS. 15. Conjunctival flap is reposited and secured by wet field cautery. 16. Subconjunctival injection of dexamethasone 0.25 ml and gentamicin 0.5 ml is given. 17. Patching of eye is done with a pad and sticking plaster or a bandage is applied.