Richard P. Kratz

Comparison of the accuracy of the Binkhorst, Colenbrander, and SRK implant power prediction formulas.

The prediction accuracy of the Binkhorst, Colenbrander, and SRK formulas were compared in five series from different sources totalling 654 cases. The SRK formula was superior to both the other formulas by having a smaller average error per case, a smaller range of error from highest minus to highest plus, and a smaller proportion of cases with greater than 2 diopters (D) of error in all five series studied. In four of the five series, the SRK formula also had the greatest proportion of cases with less than 1 D of error. The Colenbrander formula was superior to the Binkhorst formula in all five series with regard to average error, proportion of cases with less than 1 D of error, and proportion of cases with more than 2 D of error. The range of error from highest minus to highest plus was equivalent with the two formulas. All available published literature on the accuracy of implant power prediction formulas was reviewed and appears to support our findings.

the Shearing intraocular lens: a report of 1,000 cases

Implantation of Shearing and Shearing-style J-loop posterior chamber lenses in 1000 cases was associated with an absence of corneal decompensation and a low incidence of glaucoma, cystoid macular edema, iritis, vitritis and retinal detachment. The low complication rate was attributed to the posterior chamber position of the J-loop lens, which may reduce the movement of intraocular fluid and tissue.

Iris transillumination defect and microhyphema syndrome.

We present a previously undescribed delayed complication attributable to sulcus-fixated posterior chamber lenses with elliptical polypropylene haptics containing a 10 degrees anterior angulation. Clinical signs of this complication are crescent-shaped iris transillumination defects overlying the lens haptics in the peripheral iris; in some cases these are associated with single or recurrent visually significant microhyphemas. This series describes 41 eyes that contain these transillumination defects; eight of the eyes have had lens-induced intraocular hemorrhage. We estimate the overall incidence of transillumination defects in our sulcus-fixated posterior chamber lens patient population to be between 5% and 15%. Those patients who have had lens-induced hemorrhage represent slightly greater than 1%, which is higher than our incidence of cystoid macular edema or retinal detachment. It is important for all ophthalmologists to be aware of this syndrome in evaluating patients with posterior chamber lenses who present with a transient obscuration of vision.

Clinical experience with the Nd:YAG laser

This study presents the results and complications of 389 patients who were treated with the Nd:YAG laser between September 1982 and November 1983 with at least a six-month follow-up. The majority of patients had a secondary discission of the posterior capsule. Other procedures included vitreolysis, iridotomy, pupilloplasty, synechialysis, intraocular suture cutting, cutting of intraocular lens haptics, and removal of anterior pseudophakic pigmented precipitates. We have purposely avoided performing preoperative laser anterior capsulotomies and have been unsuccessful in reopening freshly sealed trabeculectomy sites. The visual acuity improved in 83.1% of patients. No statistically significant difference in visual outcome was detected in relation to the time interval between surgery and Nd:YAG laser treatment. The most common adverse finding was an increase in intraocular pressure, which occurred to some degree in 63% of patients. Rare complications included cystoid macular edema and retinal detachment. No statistical correlation between these complications and preexisting conditions or intraoperative variables could be found.

Endothelial cell loss following phacoemulsification in the pupillary plane

Endothelial cell loss following posterior chamber phacoemulsification with and without posterior chamber lens implantation was studied. Postoperative cell counts were taken four months after surgery. Three surgeons participated in this study. Posterior chamber phacoemulsification alone (30 patients) resulted in a mean cell loss of 9%, with a maximum cell loss of 22% in one patient. Posterior chamber phacoemulsification with posterior chamber lens implantation (30 patients) resulted in a mean cell loss of 8% with a maximum cell loss of 26% in one patient. Statistical analysis shows no difference in postoperative cell loss between these two groups.

Complications associated with posterior chamber lenses.

Different types of posterior chamber lenses and their complications are discussed and compared with complications of anterior chamber lenses, pupil-supported lenses, and capsular-fixated lenses. Special emphasis is placed on the Shearing intraocular lens.

Clinical evaluation of the Terry surgical keratometer

A study was designed to evaluate the usefulness of the Terry quantitative surgical keratometer as a tool to minimize surgically induced astigmatism. Two hundred and twenty-five phacoemulsifications with Shearing-style implants were performed, using identical technique. Seventy-five control cases were closed without the keratometer and 150 were closed with the keratometer. In the control group, 29.3% cases had corneal astigmatism of 3D or more, compared to 4.6% cases in the keratometer group (P < .01). The total change in astigmatism was 2.64D in the control group and 0.91D in the keratometer group (P < .02). We believe that these data demonstrate the usefulness of the Terry keratometer.

A comparative analysis of anterior chamber, iris-supported, capsule-fixated, and posterior chamber intraocular lenses following cataract extraction by phacoemulsification

Representative lens styles of four different intraocular lens groups after cataract extraction by phacoemulsification are compared. Certain cases were excluded to minimize inconsistency. Postoperative visual acuities and complications of each lens type are compared.

The Terry surgical keratometer: a 12-month follow-up report

Postoperative astigmatism was studied in two groups of patients. All patients had undergone phacoemulsification with implantation of a posterior chamber intraocular lens. The incision closure techniques in both groups were identical, with one exception: One group was closed using the Terry keratometer intraoperatively, the second group was closed without the use of this instrument. Two observations are made from the twelve-month data. First, astigmatic error in the Terry group remained constant from the postoperative keratometer readings at six weeks to the twelve-month keratometer readings. Second, while there was a considerable difference in astigmatism at six weeks between the Terry group and the control group (less astigmatism in the Terry group), the differences were no longer apparent at twelve months. Sutures were removed as necessary to improve astigmatism in the control group. No sutures were cut in the Terry group during this twelve-month period.

Kelman Phacoemulsification in the Posterior Chamber

Phacoemuisification , in the classic method described by Kelman, involves subluxation of the nucleus into the anterior chamber. This maneuver is sometimes difficultwhen cortical-nuclear adherence is great or when the pupil is miotic or the iris stiff. Once subluxed, the process of emulsification may be associated with endothelial touch by nuclear material, particularly in cases in which the anterior chamber is shallow or the nucleus brunescent. For this reason, we modified the technique of phacoemulsification to allow a more safe, efficient removal of the nucleus in the posterior chamber.