The Effect of Manipulation of Corneal Incision on Astigmatism During the Cataract Surgery

PURPOSE: To evaluate the effect of clear corneal incisional size on astigmatism during cataract surgery. METHODS: Randomized prospective study of 78 patients (108 eyes) who had received cataract surgery for a corneal astigmatism over against-the-rule (ATR) 1.0 Diopter (D) was performed. The eyes were checked by corneal topography and autorefractor preoperatively and one week, one month, two months, and six months postoperative. Group 1 included patients who received an inserted foldable intraocular lens (IOL) through a 2.8 mm incision, and Group 2 included patients who underwent IOL implantation through a corneal incision enlarged to 4 mm. RESULTS: Postoperative visual acuity showed a better visual acuity in Group 2 at both one week postoperatively (0.598+/-0.352 vs., 0.713+/-0.345, for Groups 1 and 2, respectively, p=0.046) and one month postoperatively (0.604+/-0.237 vs., 0.791+/-0.242, respectively, p=.043). There were no statistically significant differences between the groups after two and six months (p=.135, .087). Postoperative astigmatism measured by corneal topopgraphy showed 1.62+/-0.44D and, 0.94+/-0.30D for groups 1 and 2 respectively, (P=.045) at 2 months, and 1.73+/-0.45 D and, 0.92+/-0.34 D (P=.042) at six months. These results showed a statistically significant amount of residual astigmatism in Group 2. Autorefractor measurements showed similar results. There were no complications, such as wound leakage, resulting from the increased incision size. CONCLUSIONS: Widening of the incision during cataract surgery can reduce corneal astigmatism without significant complications.

Comparison of Surgically Induced Astigmatisms after Clear Corneal Incisions of Different Sizes

PURPOSE: This study was performed to assess efficiency and stability of astigmatic change by incision size after cataract surgery. METHODS: This work was designed as a retrospective, comparative, nonrandomized interventional study. A total of 121 cases of cataract surgery were reviewed in 98 patients performed by one surgeon at the Oregon Eye Institute in Eugene, OR, USA with 3-year follow-ups. All procedures were performed with the temporal approach of self-sealing incisions. The serial change in surgically induced astigmatisms were examined in all cases of three groups: Group A, cartridge injection of a foldable IOL through a 2.5 mm self-sealing incision; Group B, cartridge injection of a foldable IOL through a 3.0 mm self-sealing incision; Group C, cartridge injection of a foldable IOL through a 3.5 mm self-sealing incision. Keratometric data were obtained preoperatively, and 3 weeks, 3 months, 6 months, 9 months, 12 months, 24 months and 36 months postoperatively. Polar value analysis was performed to calculate the surgically induced astigmatism. RESULTS: The astigmatic change decreased over time in Group B (P<0.05). The other groups tended to remain in induced astigmatism. All groups showed anticlockwise torque at 3 weeks following surgery. Group B showed a decrease in deviation, but the other groups showed increases in their torque value at postoperative 12 months (P<0.05). CONCLUSIONS: The 3.0 mm incision size correlated with the least surgically induced astigmatism.

Enlargement of Incision During Phacoemulsification and Folded Intraocular Lens Implant Surgery

As a study that the incision size was changed at each step of the surgical procedure but it is different, from the universal assumption that. the incision width initially created by a keratome during cataract extraction remained same size after the end of the surgical procedure, the authors investigated a comparative study between the two studies. We used specially designed instrument for accurate measuring of the incision size in 100 eyes and the incision size was measured after the creation of the initial incision, after the coirlpletion of phacoemulsification, after widening the incision and after the folded IOL insertion. Dividing group A and B in 50 eyes respectively, we designated the incision enlargement with 3.0mm keratome as A and 3.2mm keratome as B. It appeared statistically significant widening of the incision by approximately 0.06mm after the completion of phacoemulsification, 0.19mm after the folded IOL insertion in group A and 0. 05mm, 0.1mm in group B, respectively. Future studies of the surgical techniques and the postoperative healing after small incision cataract surgery must measure the actual incision size to avoid misleading assumption that the keratome size at the beginning of the procedure determines the incision size at. the end of the procedure.

Astigmatism after Cataract Surgery using Various Wound Sizes, Configurations, and Suture Techniques

We performed a retrospective review of three hundred and twelve consecutive patients who underwent phacoemulsification and posterior chamber lens implantation between January 1, 1990 and December 31, 1990. Patients were divided into three groups according to the wound size: 3.5 - 4.0 mm(95 patients); 5.0 - 5.5mm(74 patients) and 6.5 - 7.0mm(143 patients). The patients in the 3.5 to 4.0mm did not receive suture and the patients in the 5.0 to 5.5mm wound size received one horizontal suture. The patients in the 6.5 to 7.0mm group were further evaluated by comparing those who received two horizontal sutures with those who received a running shoelace suture. At one day, one week, one month, and one year after surgery, astigmatic error was measured and a vector analysis calculation of diopters of mean induced keratometric astigmatism was performed. There was a statistically significant increase in astigmatism following 6.5 to 7.0mm incision as compared to 3.5 to 5.5mm incision at each time interval. There was no significant difference in astigmatism at any time period between the 5.0 to 5.5mm and 3.5 to 4.0mm incision groups. The longer the incision, the greater the postoperative against-the-rule astigmatic shift at the last follow up. Among those of 6.5 - 7.0 wound size, the shoelace suture technique induced greater with-the-rule astigmatic change than two horisontal sutures at postoperative day one but the difference did no longer persist at one year.