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Small Incision Cataract Surgery (Non Phaco SICS)

Dr. P. Mishra

Page 3

Topics

I.O.L. Implantation:

Viscoelastic material was injected into the capsular bag and in the anterior chamber before I.O.L. implantation. The I.O.Ls used were all indigenous, mainly Eye O’ Care, Appalens, and IMD and Cee On lenses with 5.5 to 6.5mm optics and 12.5mm to 13.5 mm overall diameter. In 370 eyes I.O.L.s were implanted in the sulcus and in 600 eyes, implanted in the bag. Viscoelastic was aspirated and anterior chamber was formed either with balanced salt solution, air bubble or both, injected through the side port (Fig.3).

Fig. 3: Trypan blue assisted rhexis

Fig. 4: Trypan blue assisted rhexis

Fig.3,4 Trypan blue assisted rhexis.

Closing the conjunctiva flap:

The conjunctival flap was closed with bipolar wet field cautery following subconjunctival injection. The sub conjuctival injection constitutes dexamethasone 0.5ml and cephazoline100mg, injected into the upper bulbar conjunctive, and eye patching applied with a pad. All these above mentioned procedures were carried out with the help of a zoom operating microscope.

Follow up

The patients were examined on the second day, 2nd week, 4th week and 6 months after the surgery. Slit lamp examination visual acuity, keratometry and indirect ophthalmoscopy were performed, any complications noticed were recorded. Reminder letters were sent to those who did not attend the regular follow up.

Results:

The mean age group of the patients was 57.8 yrs, the youngest child operated was 2yrs old. The no. of male patients was 378(38.96%) and no. of female patients was 592(61.04%). In adult cataract group nuclear cataract noticed in 24% eyes where as cortical type seen in 76% of eyes. In 96% of eyes the visual acuity corrected after one month was 6/18 or better in adult cataract group where as it is 54% in paediatric group. In 40(4.12%) eyes minimal corneal oedem was noticed, which subsided within 2 weeks of surgery. In 6(0.61%)eyes the best-corrected visual acuity was less than or equal to 6/60 because of severe corneal oedema. Three eyes had decentred I.O.L. and in other two implant dislocated in to vitreous cavity, which were explanted immediately. In one eye retinal detachment was noticed in the post operative period, which was pre-existing. Mild iritis was noticed in 80(8.24%) eyes and posterior capsular opacification was seen in 82(8.45%) eyes. Intraoperatively, posterior capsular rent was noticed in 12(1.23%) eyes out of which 8 eyes had vitreous loss, which was managed by anterior vitrectomy. In two eyes irido dialysis in the inferoior part with severe hyphema was encountered. In two cases of traumatic cataract the lenses were subluxated, which were removed through sclerocorneal tunnel, a/c IOL implanted in one and in other case scleral fixation IOL done following vitrectomy, visual acuity improved to 6/18 and 6/12 respectively. One eye (0.10%) developed severe endophthalmitis, we could not save that eye inspite of intravitreal antibiotics and vitrectomy.

Discussion:

The postoperative visual acuity, best corrected was 6/12-6/18 or better in almost 96% of cases at 4 weeks follow up in senile cataract group where as in paediatric group it is only 54%. In more than 80% of eyes in the adult group were having severely impaired vision before surgery, this was reduced to 1.03% at 4 weeks of surgery. In paediatric group, the percentage of good post operative visual acuity is low because there are so many factors, like age of onset of cataract, time of surgery, type of surgery and post operative management that affect visual prognosis in children. In 6(0.61%) eyes there were irreversible corneal oedema because of endothelial trauma. This complication will be much lower as one’s learning curve is overcome. The severe corneal oedema was due to endothelial decompensation, which was mostly seen in learning phase. In 2 (0.20%) eyes there were inferior iridodialysis and total hyphaema, which cleared slowly, and visual acuity improved to 6/24 and 6/36 after 2 months of surgery. The iridodialysis in the lower part was because of iris trapped in between microvectis and nucleus during delivery of nucleus. This can be avoided by injecting adequate amount of viscoelastic into the anterior chamber both above and below the nucleus so that free floating nucleus can be removed easily. In another two eyes there was zonular dialysis, implants were dislocating into the vitreous, which were explanted intra-operatively, vitrectomy was done and anterior chamber lenses were implanted. In other 12 (1.23%) eyes there were posterior capsular rent, out of which 8 had vitreous loss, which were managed by vitrectomy, IOL implanted in the sulcus in three eyes and in other five, it was implanted in the anterior chamber. The entire surgical procedure requires a good amount of surgical skill and additional training. Once the technique is mastered the surgery is easier, faster and the complication rate is low. In 4 eyes of complicated cataract there was posterior capsular plaques, it was difficult to aspirate, however in two cases re operation, I/A was done easily in the second post operative week, following which visual acuity improved to 6/12 and 6/18 respectively.

In early eighties Kansas described the phaco-fracture and Luther Fry, the phaco-sandwich technique for nucleus removal in SICS. Both these procedures are difficult because two instruments are introduced on either side of nucleus and there is every likelihood of endothelial damage either by instruments or by lens fragments. That’s the reason why we do not recommend any instrument in between nucleus and endothelium during nucleus delivery. Nucleus extraction with an irrigating vectis was first described by Steinert. Michael Bluementhal described nucleus delivery by using anterior chamber maintainer, he used to do all maneuvers underfluid, in both these procedure there is every chance of endothelial damage, because fluid never protects the endothelium in a better way. Richard Gianetti in 1996 reaffirmed that the nucleus capture is an inexpensive, phacoless, repeatable and relatively easy method of performing tunnel incision cataract surgery. He also stressed that no side port incision is required, surgeons can obtain the benefits of small self-sealing incision without the added cost of phaco. In first 200 cases of this study, no side port entry was done, however, at present we routinely do side port entry for easy capsulorhexis and aspiration of sub incisional cortex. We have observed that the endothelial loss is around 11%( our own unbublishrd data) in SICS, this usually occurs either during nucleus expression or during I/A. Lens fragments may touch the corneal endothelium during irrigation and aspiration.

Astigmatism is not so high as expected in spite of large incision in hard cataract, it has been observed that it is never more than 1.5-2D at 4 weeks follow up. The mean surgical induced astigmatism was 2.12 – 0.72 on the 2nd post operative week and reduced to 1.42 – 0.68 at the end of 4th week. In 87% of eyes the induced astigmatism was less than 1.50D. In our series most of the patient had against the rule astigmatism and showed faster astigmatic decay over time. We have observed that, even for incision of 8mm in nuclear cataract, there is no need of sutures, provided the incision is placed more posterior to limbus and tunnel is dissected longer, this also minimizes postoperative astigmatism. Longer(wider) the tunnel lesser the astigmatism it produces. Despite longer incision in some cases, it is a fact that we could achieve watertight, self-sealing, suture-less wound in almost 100% of cases of adult cataract and in children of more than 2 yrs of age. We routinely reform the anterior chamber with air bubble and BSS at end of the surgery in children to make it suture less.


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