Clinical results of endocapsular phacoemulsification and complete in-the-bag intraocular lens fixation

Comparison of peristaltic and Venturi pumps in bimanual microincisional cataract surgery

Comparison of peristaltic and Venturi pumps in bimanual microincision phacoemulsification on the success of the cataract surgery by using sleeveless phaco tip. Bimanual microincision phacoemulsification was done in 49 eyes using a 1.4-mm temporal clear corneal incision. A peristaltic pump was used in 23 eyes, and a Venturi pump was used in 26 eyes for phacoemulsification. Intraoperative complications, anterior chamber stability, and mean duration of surgery were recorded. Duration of surgery was shorter in the Venturi pump group. Anterior chamber stability could not be established in 17 eyes in the peristaltic pump group; it was established in all eyes in the Venturi pump group. Corneal burns were observed in two eyes in the peristaltic pump group and no eyes in the Venturi pump group. Use of a Venturi pump system and a vented gas-forced infusion system can significantly shorten surgery time and reduce risk of thermal burns.

Comparison of Phaconit Rollable IOL with Acrylic Foldable IOL

BACKGROUND

Phaconit or ultra micro incision phacoemulsification cataract surgery involves phacoemulsification through a 0.9 millimetre sleeveless phaco tip and irrigating chopper followed by implantation of a rollable intraocular lens. The procedure leads to negligible astigmatism and faster visual recovery as compared to phacoemulsification with a foldable intraocular lens.

METHODS

This prospective study analysed 80 cases of sub millimetre phaconit surgery with implantation of rollable intraocular lenses(IOL) in 40 cases and acrylic foldable IOL in the remaining 40 cases. Evaluation of efficacy and adaptability of procedure, equipment settings, operative constraints, postoperative complications, keratometric and topographic evaluation of induced astigmatism with visual outcome and patient's rehabilitation were studied.

RESULTS

The intraoperative complications were surge/ chamber collapse in 16 (20%), iris chaffing in one and corneal burns in two cases. All cases had an induced astigmatism of less than or equal to ± 0.25 D in four to six weeks after rollable IOL and ± 0.5 D to ± 0.75 D after acrylic IOL implantation. All patients had best-corrected visual acuity of 6/6 by third post operative day.

CONCLUSION

Phaconit with rollable IOL is a perfect blend of surgical skill, application of technology and ultra thin IOL.

Ultrasmall-incision bimanual phacoemulsification and AcrySof SA30AL implantation through a 2.2 mm incision

Phacoemulsification and aspiration were performed with a sleeveless ultrasound tip through an ultrasmall incision (1.2 to 1.4 mm) using a 20-gauge irrigating hook through a side port to infuse the anterior chamber. After the lens was extracted, the incision was enlarged to 2.2 mm and a single-piece intraocular lens (AcrySof SA30AL, Alcon) with an optic diameter of 5.5 mm was inserted. By modifying the new injector system, the AcrySof SA30AL could be inserted through a 2.2 mm incision in 100% of cases (63 eyes) in which it was feasible to use a thin lens having a central thickness of less than 20 diopters (D). A 2.2 mm incision was also used successfully in 54% of cases (42 of 78 eyes) that required a lens with a central thickness of 20 D or higher.

Corticocapsular adhesions and their effect during cataract surgery

PURPOSE

To identify the types of corticocapsular adhesions by their preoperative clinical appearance and evaluate the difficulties they pose during cataract surgery.

SETTING

Iladevi Cataract & IOL Research Center, Ahmedabad, India.

METHODS

Seventy-six eyes with age-related senile cataract scheduled for phacoemulsification were identified as having corticocapsular adhesions. Preoperatively, the eyes were assessed at the slitlamp to determine the type of corticocapsular adhesions present. During surgery, the surgeon graded nucleus rotation after single-site cortical-cleaving hydrodissection as easy, difficult, or not possible. Additional multiquadrant-focal hydrodissection was performed. The surgeon's impressions of the presence of corticocapsular adhesions and visualization of the furry surface of the epinucleus were noted.

RESULTS

Corticocapsular adhesions were confirmed in 86.84% of eyes. Equatorial corticocapsular adhesions alone or in combination were present in 72 eyes (94.74%) eyes, anterior corticocapsular adhesions in 40 (52.74%), and posterior corticocapsular adhesions in 42 (56.26%). Rotation of nucleus was not possible in 47.37% eyes, difficult in 39.47%, and easy in 13.16%.

CONCLUSIONS

The surgeon should perform a thorough preoperative slitlamp evaluation in extreme gaze with a fully dilated pupil. Equatorial corticocapsular adhesions, which were present in most eyes, made nucleus rotation difficult. Additional multiquadrant and focal cortical-cleaving hydrodissection helped separate the adhesions and achieve successful rotation.

[History of the development of intraocular lenses]

Even though cataract surgery has been practiced for over 2000 years, modern cataract surgery started just some 50 years ago. with the first IOL implantation by Sir Harold Ridley. The development of intraocular lenses was accompanied by great successes and disasters. With the fast development of cataract surgical techniques over the past 15 years (ECCE, Phacoemulsification, Capsulorhexis) a successful marriage between IOL-developments and surgery was established. Indication profiles for cataract surgery and IOL implantation extended to more and more patient groups. At this time classical cataract surgery is further developing into refractive intraocular lens surgery to correct higher ametropia in clear lens or phakic eyes. This development was only possible because of the improvements of surgical techniques and implants in classical cataract surgery.

Management of posterior capsule tears

Any breach in the continuity of the posterior capsule is defined as a posterior capsule tear. Posterior capsule tears can be preexisting (congenital or traumatic), spontaneous, or intrasurgical. Preexisting/congenital posterior capsule tears have been related to an intrauterine insult. Posterior capsule tears due to trauma may occur as a consequence of direct mechanical impact due to perforation or blunt injury. Depending on the duration of time between the posterior capsular trauma and the cataract surgery, these posterior capsule tears can have different features. Intrasurgical posterior capsule tears are the most common and can occur during any stage of cataract surgery. Also, they may be planned in the form of primary posterior capsulorhexis. The conventional management consists of prevention of mixture of cortical matter with vitreous, dry aspiration, and anterior vitrectomy, if required. In addition, during phacoemulsification low flow rate, high vacuum, and low ultrasound are advocated if a posterior capsule tear occurs. Dislocated nucleus or nuclear fragments require vitrectomy and the use of perfluorocarbon liquids. In the presence of a posterior capsule tear, the IOL can be placed in the sulcus, if the capsular rim is available, or in the bag, if the tear is small. Scleral fixated posterior chamber lenses and anterior chamber IOLs can be implanted when the posterior capsule tear is large.

Corneal endothelial cell loss caused by detached opacified anterior lens capsule in the anterior chamber

From 1984 to 1986, we performed cataract surgery through a 1.5 mm anterior capsule hole in 77 eyes. The hole was enlarged to 6.0 mm by a slit incision, and an intraocular lens was implanted into an almost completely intact capsular bag. Twelve (16%) eyes developed severe postoperative anterior capsule opacification. The opacified central anterior capsule, approximately 5 mm in diameter, was detached by can-opener anterior capsulotomy using a neodymium:YAG laser and fell into the inferior anterior chamber. Inferior corneal endothelial cell loss occurred in nine of the 12 eyes within 20 months after detachment; in six of the nine, inferior corneal endothelial cell density decreased 50% more than central cornea cell density. This method will be unsuitable for treating the extensive anterior capsule opacification that will occur when endocapsular cataract surgery that retains most of the lens capsule is widely performed in the future.

Posterior capsule opacification

A complication of extracapsular cataract extraction with or without posterior chamber intraocular lens (PC-IOL) implantation is posterior capsule opacification. This condition is usually secondary to a proliferation and migration of residual lens epithelial cells. Opacification may be reduced by atraumatic surgery and thorough cortical clean-up. Clinical, pathological and experimental studies have shown that use of hydrodissection, the continuous curvilinear capsulorhexis and specific IOL designs may help reduce the incidence of this complication. Capsular-fixated, one-piece all-polymethylmethacrylate PC-IOLs with a C-shaped loop configuration and a posterior convexity of the optic are effective. Polymethylmethacrylate loops that retain "memory" create a symmetric, radial stretch on the posterior capsule after in-the-bag placement, leading to a more complete contact between the posterior surface of the IOL optic and the taut capsule. This may help form a barrier against central migration of epithelial cells into the visual axis. Various pharmacological and immunological methods are being investigated but conclusive data on these modalities are not yet available.

Intercapsular cataract surgery with lens epithelial cell removal. Part IV: Capsular fibrosis induced by poly(methyl methacrylate)

Characteristic lens epithelial cell behavior in the pseudophakic eye was examined by comparing 30 eyes that had extracapsular cataract surgery by the intercapsular technique and posterior chamber intraocular lens (IOL) implantation with lens epithelial cell removal but without anterior capsule capsulectomy and nine aphakic eyes that had the same procedure but without posterior chamber lens implantation over a mean follow-up period of 30 and 23 months, respectively. Fibrous anterior capsule opacification was observed in 83% of the pseudophakic eyes in the area of contact with the IOL, while the region beyond the margin of the IOL remained transparent. Fibrous anterior capsular opacification was not noted in the aphakic eyes. This suggests that the IOL material, poly(methyl methacrylate), stimulates lens epithelial cells to undergo fibrous metaplasia and to produce collagen fibers. Various cytokines such as IL-1 and TGF-beta synthesized by lens epithelial cells may play a crucial role as mediators in the process. We recommend that this effect be considered as a parameter of biocompatibility in developing and evaluating new biomaterials.

Results of 87 cases of intraocular lens implantation at the front of the whole capsular bag

To prevent or delay Elschnig pearl formation, we performed an unusual surgical technique on 87 patients: intraocular lens implantation at the front of the whole capsular bag. We tried to obtain tight adhesion between the anterior and posterior capsules so the lens epithelial cells could not proliferate and form Elschnig pearls. In fact, the patients exhibited no Elschnig pearls or Soemmering's ring, but developed large anterior capsular folds and a multilayer cell membrane between both capsules after two (three cases), six (19 cases), and 12 months (14 cases). This led to a decrease in visual acuity, and a Nd:YAG laser anterior and posterior capsulotomy was required in most cases (83%). Several months later, these eyes developed enormous Elschnig pearls emanating centrifugally from the laser opening, strongly suggesting that lens epithelial cells require aqueous humor for Elschnig pearl transformation. Since it is not yet possible to obtain perfect adhesion between anterior and posterior capsules, our results confirm the need to remove the anterior capsule after extracapsular cataract extraction.

Anterior capsule cleaning with an ultrasound irrigating scratcher

Ultrasound anterior capsule cleaning was performed in 22 intercapsular cataract extraction cases. These eyes were compared with 24 others which had the intercapsular procedure performed by the same surgeon without ultrasound capsule cleaning. Eyes were randomly assigned to one procedure from a group of 62 cataract patients. Histologic specimens of the anterior capsule flap removed from the optical zone at the end of the procedure were examined. The anterior capsules cleaned by ultrasound appeared more transparent, without residual lens fibers with fewer epithelial cells. Ultrasound cleaning seems effective in preventing anterior capsular fibrosis and opacification.

Cataract surgery. Current approaches

Cataract surgery in the dog can be a highly successful and rewarding technique for restoring vision to the cataract patient. Coexisting ocular conditions can complicate cataract surgery or be a contraindication for lens removal; these include KCS, uveitis, glaucoma, lens subluxation, and retinal disease. Techniques for cataract surgery include intracapsular cataract extraction, extracapsular cataract extraction, and phacofragmentation, both extracapsular and endocapsular (intercapsular). Phacofragmentation is probably the most successful technique in the dog at this time. Postoperative complications include uveitis, hyphema, glaucoma, capsular opacities, corneal endothelial damage, and retinal detachments. Newer methods of dealing with these problems include the use of viscoelastic materials and IOL implants intraoperatively and the use of the Nd:YAG laser for posterior capsulotomies postoperatively.

Endocapsular closed chamber technique for disc lens implantation

A simple endocapsular technique for implantation of an 8 mm disc lens is described. Its main features are a scleral three-plane incision, a vertical-stab capsulotomy, cortical hydrodissection, a closed chamber technique during placement of the intraocular lens in the capsular bag, implantation under air and fluid, wherever feasible, and optional anterior capsulectomy with a 27-gauge needle bent at the tip. This technique requires no complicated equipment and allows atraumatic implantation of the disc lens with maximum control of anterior chamber depth.

Anterior capsule-supported intraocular lens. A new lens for small-incision surgery and for sealing the capsular opening

A new intraocular lens made of PMMA and fixed in the anterior capsular opening is introduced. The lens diameter is 4 mm and the lens has no haptics in the conventional sense but is finely grooved around the circumference edge. The lens is inserted into the anterior capsule via a very small-diameter opening created by mini-circular capsulorhexis. The anterior capsular opening, with a round, smooth-edged margin, avoids stress concentration and, therefore, the capsule does not easily tear. This opening catches the lens and chokes it along the grooved edge. In animal experiments, firm fixation was obtained. This lens may be adequate for small-incision surgery, and in the future it may be used to prevent leakage of filling material during refilling of the lens, since it acts as a part of the anterior capsule and seals the capsular opening completely.

Capsular bag distension after endophacoemulsification and posterior chamber intraocular lens implantation

Six cases of capsular bag distension after capsulorhexis, endophacoemulsification, and posterior chamber intraocular lens (IOL) implantation are presented. Five cases had prominent posterior subcapsular cataracts preoperatively. In three cases, the anterior chamber depths were shallower and the apparent refractive errors were more myopic than normal after surgery. All six cases exhibited an apparent early complete sealing of the anterior capsular remnant against the anterior IOL optic. In each case, the capsular bag contained moderate particulate debris and flare while the adjacent vitreous and anterior chambers were clear. I suspect the particles are epithelial cell and cortical debris suspended in a fluid comprising lens epithelial protein, cellular breakdown products, balanced salt solution, and water. Five cases have received no specific treatment. In one case, a neodymium:YAG laser anterior capsulotomy allowed a forward egress of fluid from the distended capsular bag and a return to normal pseudophakic anatomy.

Intercapsular cataract surgery with lens epithelial cell removal. Part I: Without capsulorhexis

Endocapsular phacoemulsification or intercapsular cataract extraction with lens epithelial cell removal using an ultrasound technique was performed on 30 eyes. The anterior capsule was not removed after posterior chamber intraocular lens implantation. After a mean follow-up period of 16.4 +/- 2.8 months, anterior capsule opacification was observed in six eyes, posterior synechias in six eyes, and shrinkage of the anterior capsule below the pupillary area, which resulted from the large opening needed for the intercapsular extraction, in 11 eyes. Other postoperative complications caused by lens epithelial cells such as posterior capsule opacification, intraocular lens dislocation, and fibrinous reaction did not occur. These results suggest it is necessary to remove the lens epithelial cells and the anterior capsule after posterior chamber lens implantation in intercapsular cataract extraction.

Protective effect of the anterior lens capsule during extracapsular cataract extraction. Part I. Experimental animal study

In an experimental study using albino Rex rabbits, the intercapsular cataract extraction (ICCE) technique was performed in 20 eyes with a small anterior capsulotomy. A large, can opener capsulotomy was performed in another 20 eyes, and 10 unoperated eyes served as controls. Endothelial cell loss was determined by vital staining with Trypan blue and Alizarin red S stains. Average endothelial cell loss with the ICCE technique was 1.2%; with the can opener technique, the average cell loss was 6.6%. This difference was statistically significant (P less than 0.01). The percentage of endothelial cell loss in the control eyes was 0.5. A positive correlation between endothelial cell loss related to phacoemulsification time and/or the amount of irrigating fluid used existed for the can opener group only (P less than 0.01). These results demonstrate that the presence of an almost intact anterior lens capsule during removal of lens substance is protective to the corneal endothelium.

Specular microscopy of the anterior lens capsule after endocapsular lens implantation

Endocapsular phacoemulsification and complete in-the-bag intraocular lens (IOL) fixation was performed on 77 eyes. Specular microscopy of the anterior lens capsule was performed postoperatively, and the process of anterior capsule opacification after endocapsular cataract surgery was classified. Lens epithelial cells on the inner surface of the anterior lens capsule, facing the optical portion of the IOL, underwent a diffuse fibrosis. In more peripheral areas, where the anterior and posterior capsules were tightly adherent, the regularly proliferating lens epithelial cells retained their polygonal shape. These findings suggest the possibility of retaining the transparency of the anterior lens capsule postoperatively by refilling the capsular bag to apply internal pressure.

Effect of freezing on lens epithelial cell growth

The effect of freezing on the growth of rat lens epithelial cells was studied in vitro. We found that 80% of the lens epithelial cells died after freezing at -45 degrees C for two hours and that the surviving cells could grow with the addition of growth factors or when placed on a sheet of type 4 collagen, but not when placed on a plain plastic culture dish. These results suggest that the surviving cells are at the Go phase of the cell cycle and that type 4 collagen or growth factors can initiate cell division.

Minimal lift-multiple rotation technique for capsular bag phacoemulsification and intraocular lens fixation

A method of capsular bag phacoemulsification is outlined step-by-step. The surgical technique has proven safe and efficient and preserves the architecture of the capsular bag for hard or soft intraocular lens implantation. It represents a practical, modern method for cataract extraction and intraocular lens implantation.

Roundel phacoemulsification technique for in-the-bag intraocular lens fixation

We introduce a new phacoemulsification technique that removes a cataract and retains a 5-mm round, tear-free opening in the anterior capsule, and present the results in 100 eyes. This technique is extremely useful in retaining the integrity of the capsular bag, which is indispensable for long-term capsular bag fixation, and is also a preliminary step in mastering endocapsular (intercapsular) phacoemulsification. We call this the roundel technique.