Ординатура / Офтальмология / Английские материалы / The Art of Phacoemulsification_Mehta, Alpar_2001

The Use of Foldable Lenses and Injectors

Foldable lenses are ideal as they permit the insertion of the IOL with none or very little enlargement of the incision. If one is not using an injector, (Unfolder, Allergan) it is important to slightly enlarge the cornea ( typically the 6.00 mm AcrySof IOL’s require a 4.1 mm opening, though the newer 5.5 mm AcrySof can be passed via 3.25 mm opening easily). Always make the opening a little larger rather than trying to force the lenses via a smaller incision as the force leads to shearing of the cornea

which is uncontrolled and often leads to unstable astigmatism. This is important since a fair amount of gymnastics have been done in the chamber for removal of these cataracts which invariably leads to stress on the corneal tunnel. Preference should be always to do a controlled incision rather than force the implant in which leads to an uncontrolled corneal shear.

The injectable lenses (the author’s preference is an Allergan SI 40 lens) comfortably go through a 2.8 mm opening using the newer injectors. Two steps at this point of insertion are important. Since the capsule in suprahard cataract is thin and friable do not do any manipulations on its surface. Be particularly careful when rotating the IOL in the bag. Use copious viscoelastic. In using the Chiron plate haptic IOL’s do not try and manipulate plate haptic lenses to change their position once placed in the bag, as the posterior capsule will ruck and tear. Especially for plate haptic, the use of iced methylcellulose damps down the expulsion force. Do not release close to the posterior capsule. Use delicacy in placing lens in the bag. Any force leads to a lost lens.

Finally a sobering thought. Injectable lenses, especially plate haptics silicones, injected in capsules with doubtful integrity may disappear in the vitreous in a jiffy. When in doubt use looped haptics. As a personal preference, when in trouble, the Allergan loop haptics of the SL30 (prolene-based loops) are especially forgiving. Hema ( Storz Hydroview lenses), too seem to work well in these dangerous situations.

For the surgeon who is commencing and who wishes to go slowly he or she may consider the possibility of utilizing the Hema Endothelial Hood as a safety net. Here a specially-designed Hema contact lens of diameter, 8.5 to 9.00 mm which is inserted intra-camerally, after doing capsulorrhexis. It is placed and stays in intimate contact with the endothelium during the phacoemulsification procedure and is then removed at the end of the procedure. It is especially useful in hard cataracts with an endothelially compromised cornea {(e.g. Fuchs’) (Mehta 95’, 97’, 99’)}.

CONCLUSION

Though suprahard cataracts have always been thought a problem, a proper analysis and a well-thought-out game plan will make the procedure simple to carry out with a high level of proficiency and reproducibility.

No other procedure will be as rewarding, and soul-satisfying to the surgeon, with the utmost patient satisfaction, as a really beautifully phacoed difficult suprahard cataract.

SUPRAHARD CATARACTS: THEIR EVALUATION AND MANAGEMENT 313

FURTHER READING

1.Mehta KR: Phacoemulsification cataract extraction with foldable IOLS—first 50 cases. All India Ophthl Soc Proc 56-60,1989.

2.Mehta KR: Posterior capsular capsulorrhexis with shallow core vitrectomy following implantation in Paediatric Cataracts. All India Ophthl Soc Proc 207-10,1995.

3.Mehta KR: The new clover leaf stabiliser (CLS) for the safe and effective insertion of posterior chamber IOL over a broken capsular face. All India Ophthl Soc Proc 251-53,1995.

4.Mehta KR: An advanced but simple keratometer for control of postoperative stigmatism. All India Ophthl Soc Proc 122-23, 1990.

5.Mehta KR: Shelve and shear phacoemulsification. All India Ophthl Soc Proc (Mumbai), 1995.

6.Mehta KR: Phaco-levitation: a peaceful way. All India Ophthl Soc Proc (Chandigarh), 1996.

7.Mehta KR: The prephaco split technique using the contrasplit forceps–a new technique. All India Ophthl Soc Proc, 1998.

8.Mehta KR: The tripod posterior chamber flexible acrylic implant—the answer to better stability.APIIA Conference, 1997.

9.Mehta KR: Intralenticular “hubbing” technique for simple eye camp phacoemulsification—a simple technique. APIIA Conference, 1997.

10.Mehta KR: Astigmatic control using the new curved laminating keratotomy technique. APIIA Conference, 1997.

11.Mehta KR: The tripod posterior chamber foldable acrylic lens. Proc of SAARC Conference, Nepal, 1994.

12.Mehta KR: Phacoemulsification, the “roller-flip” way for suprahard cataracts—it works great. Proc of SAARC Conference, Nepal, 1994.

13.Mehta KR: Intralenticular phacoemulsification—a new technique. Proc of SAARC Conference, Nepal, 1994.

14.Mehta KR: Management of subincisional cortex in small incision cataract surgery (SICS). Proc of SAARC Conference, Nepal, 1994.

15.Mehta KR: Intralenticular “hubbing” phaco technique for safe phaco. Proc of SAARC Conference, Nepal, 1994.

16.Mehta KR: Effective endothelial cell protection during phacoemulsification with Hema intracameral contact lens (HICL). Proc of SAARC Conference, Nepal, 1994.

17.Mehta KR: The new multiport phaco tip for safer, more effective phacoemulsification, with virtually zero capsular damage. Proc of SAARC Conference, Nepal, 1994.

STRETCH PUPILLOPLASTY FOR SMALL PUPIL MANAGEMENT IN CATARACT SURGERY 315

Fig. 29.2: Beginning of stretch

Fig. 29.3: Midstretch

This gives a pupil of adequate size for easy capsulorrhexis and subsequent cataract surgery in nearly all cases. In general, the smaller the pupil, the better the effect. The author does have a set of Grieshaber iris retractors available, but have not had to cut the iris or use iris retractors in a single case since using this technique.

Technical Tips and Caveats

•With small fibrotic pupils, there may be a tendency to develop iris tears. These are usually small and multiple. Stretching slowly (approximately 3 seconds) may help lessen the severity of these tears. The author has yet had an iris

316 THE ART OF PHACOEMULSIFICATION

Fig. 29.4: Fully stretched

Fig. 29.5: Start of expansion with viscoelastic

tear large enough to cause problems and has not had significant iris bleeding. Hold for a second or so at maximum stretch.

•Be sure to stretch fully out to the limbus in both directions to get maximal effect. Only one stretch is necessary. Additional stretches give little additional benefit. (the author used to go in through the side port and stretch again 90 degrees away, but stopped this when it seemed to give little additional effect (Figs 29.8 to 12). These additional stretches also seem to make the iris more “floppy” and likely to catch in the phaco tip).

•The pupil may remain permanently larger, particularly in small fibrotic pupils with iris atrophy. These tend to develop iris tears. These tears are rarely large, and may really be somewhat of a benefit, especially in glaucoma cases, in

318 THE ART OF PHACOEMULSIFICATION

Fig. 29.8: Atrophic iris

Fig. 29.9: Stretch with sphincter tear

After pupil stretch, cataract surgery proceeds as per one’s usual technique. The author prefers using phaco, however, this procedure gives adequate pupillary size for a large capsulorrhexis to allow planned extra also. The author likes to groove and crack the nucleus, particularly in the small pupil cases, as he is uncomfortable with loosing visualization of the chopper beneath the iris periphery. Grooving the nucleus deeply just in the center portion allows an easy crack in nearly all cases if grooving is carried deep enough. The peripheral nucleus does not have to be grooved. The two halves are then rotated 90 degrees. The phaco tip is embedded in the distal half to hold it and it is divided again in two or more pieces depending on nucleus density. The second half is then rotated and cracked in a similar manner. This is done under low flow and vacuum. Then, with high flow and vacuum, these cracked fragments are aspirated and emulsified (Figs 29.12 to 15).

STRETCH PUPILLOPLASTY FOR SMALL PUPIL MANAGEMENT IN CATARACT SURGERY 319

Fig. 29.10: After expansion with viscoelastic

Fig. 29.11: One day postoperation

Irrigation-aspiration (I-A) is done by one’s preferred technique. The author prefers to use the automated I-A and then split irrigation and aspiration to go in through the side port for subincisional cortex. The foldable (or non-foldable) lens of one’s choice is then inserted (Fig. 29.16).

The author has used this technique since 1992, and stretch approximately 10% of his pupils—this would extrapolate out to be something over 700 cases in which The author has used it. Any surgical procedure, of course, has some complication risk, but the author has yet to encounter his first significant complication resulting from this pupil stretching technique.

STRETCH PUPILLOPLASTY FOR SMALL PUPIL MANAGEMENT IN CATARACT SURGERY 321

Fig. 29.15: Aspirate and emulsify on high vacuum

Fig. 29.16: A cannula is inserted through the side port for subincisional cortex

He would like to recommend this procedure for those of the ophthalmologists who have not used it. The author thinks they will find it very safe and effective.

“Try it; you’ll like it”.