Shiro Hatta

Management of posterior capsule rupture during phacoemulsification using the dry technique

&NA; To manage posterior capsule rupture during phacoemulsification, we use a dry technique in which all procedures are performed without an irrigation/aspiration system. The dry technique is characterized by (1) continuous viscoelastic injection instead of fluid irrigation to maintain anterior chamber depth with the posterior capsule and vitreous located posteriorly and (2) static removal of most residual lens material by viscoexpression and/or manual small incision extracapsular cataract extraction without aspiration and dynamic water flow. In 16 cases of posterior capsule rupture managed using the dry technique, the residual nucleus and cortex were readily removed with minimum extension of the ruptured area and new vitreous loss. Although large amounts of viscoelastic material (mean 5.8 mL) were required, rapid and stable visual recovery was comparable to that in patients having uneventful surgery. The dry system is a safe and reliable technique for managing posterior capsule rupture during phacoemulsification.

Manual sutureless cataract surgery using a claw vectis

&NA; Two‐handed sandwich methods of extracapsular cataract extraction using a self‐sealing incision have proved difficult for many inexperienced surgeons. We developed a simpler 1‐handed technique using a claw vectis—a vectis with a claw placed on its tip. When the nucleus is pulled through the scleral tunnel, it is fixed by the claw and is smoothly removed from a wound of a size comparable to that in the sandwich method. During nucleus removal, viscoelastic material is constantly injected through the irrigation vectis to maintain the anterior chamber depth, resulting in a low incidence of complications. We have performed 620 cases using the technique and found it safe and easy for both novice and experienced surgeons.

Clinical application of full-arc, depth-dependent, astigmatic keratotomy.

Purpose. To report a case series of the first clinical application of a new method of astigmatic keratotomy termed full-arc, depth-dependent astigmatic keratotomy (FDAK). Methods. The type of astigmatism was analyzed by corneal topography. If the astigmatism was regular, paired arcuate incisions of 90° length were used. Incision depth varied between 40% and 75% of local corneal thickness for controlling the level of astigmatic correction. Results. All 13 cases had regular astigmatism, and paired arcuate incisions of 90° length were used. Four cases with incisions at 40% depth, five cases at 50% depth, three cases at 60% depth, and one case at 75% depth induced vector astigmatic change of 0.93 ± 0.33 D, 1.92 ± 0.24 D, 3.17 ± 0.26 D, and 4.44 D, respectively, 3 months after surgery. From 3 months to 1 year or 3 years, the postoperative astigmatism was stable, and no cases showed astigmatic regression of 0.50 D or more. Every topographic difference map indicated effective flattening and steepening occurring with a 1:1 coupling ratio. All postoperative color maps showed a marked improvement in corneal sphericity. Conclusions. In FDAK using paired 90° incisions at 40–75% depth, an almost linear relationship between the incision depth and degree of astigmatic change was observed. FDAK may be an effective and safe method of astigmatic keratotomy that accurately controls the level of astigmatic correction. More clinical applications are necessary for drawing final conclusions and making a nomogram.

Experimental study using pig eyes for realizing ideal astigmatic keratotomy.

Purpose. The effects of varying the incision length and depth were analyzed using pig eyes to acquire information for realizing an ideal method of astigmatic keratotomy (AK). Methods. Single and paired arcuate incisions were made on pig corneas using a diamond knife. Incisions with varying lengths of 40°, 60°, and 90° were made with the incision depth fixed at 90% of corneal thickness. Next, paired incisions with varying incision depth from 20% to 95% of corneal thickness were made with the incision length fixed at 90°. The changes in corneal shape were analyzed using corneal topography and the degrees of astigmatic change were measured using a surgical keratometer. Results. For short single and paired incisions (40° or 60° in length), narrow areas of flattenings occurred, and steepenings were observed on both sides adjacent to the flattened areas. For long paired incisions of 90° length, wide areas of flattenings and steepenings were observed with an approximately 1:1 coupling ratio, and a positive linear relationship between the incision depth and degree of astigmatic change was observed in the range of incision depth between 40% and 80% of corneal thickness. Conclusion. This experimental study suggests that for achieving ideal corneal sphericity after AK, long incisions covering the entire steep areas (paired 90° incisions for regular astigmatism) should be used and the degree of astigmatic correction may be controlled by varying the incision depth.