Superior Scleral Tunnel Incision Research Articles

Comparative study of intraocular lens implantation through 3.0 mm temporal clear corneal and superior scleral tunnel self-sealing incisions

Purpose: To compare the clinical outcome of phacoemulsification and foldable silicone intraocular lens (IOL) implantation through a 3.0 mm temporal clear corneal incision and a 3.0 mm superior scleral tunnel incision.Setting: Department of Ophthalmology, Yodogawa Christian Hospital, Osaka, Japan.Methods: Eighty cataractous eyes of 78 patients with pre-existing against-the-rule (ATR) astigmatism were recruited for this prospective, randomized study. The patients were assigned to one of the two groups. Data on uncorrected and corrected visual acuities, keratometry, flare intensity measurement, and central cornea endothelial cell count were evaluated preoperatively and at 2 days, 1 week, and 1 and 3 months postoperatively.Results: Although the pre-existing keratometric cylinder decreased in the temporal clear corneal incision group and increased in the superior scleral tunnel incision group, the amount of cylinder shift was not significantly different. Mean scalar shift of keratometric cylinder in the corneal incision group was 1.19 diopters (D) at 2 days postoperatively, 0.86 D at 1 week, and 0.56 D at 3 months and in the scleral incision group, 1.09 D at 2 days, 0.76 D at 1 week, and 0.65 D at 3 months. Eighty percent of the eyes in each group achieved an uncorrected visual acuity of 20/40 or better from the second day postoperatively. No statistically significant difference in visual rehabilitation or other parameters was noted between the groups throughout the study. Complications including corneal endothelial cell loss and wound incompetence requiring suturing were observed in the temporal clear corneal incision group.Conclusions: Both incisions offered satisfactory clinical results, but the superior scleral tunnel incision resulted in fewer complications. Minimal corneal keratometric change induced by a 3.0 mm incision was not related to uncorrected visual rehabilitation.

Corneal Astigmatism After Phacoemulsification and Lens Implantation Through Unsutured Scleral and Corneal Tunnel Incisions

We compared the changes in corneal astigmatism after phacoemulsification and intraocular lens implantation in 93 consecutive eyes with unsutured 4-mm superior scleral tunnel incisions to those through 105 consecutive eyes with unsutured 3.2- to 3.5-mm temporal corneal tunnel incisions. Keratometry measurements were obtained preoperatively and at postoperative day 1, week 1, and week 6. Group differences in scalar and vector astigmatism were compared by using analysis of variance methods. Mean scalar astigmatism in the scleral incision group changed from preoperative astigmatism by 0.65 diopter at postoperative day 1, 0.37 diopter at postoperative week 1, and 0.13 diopter at postoperative week 6. Mean scalar astigmatism in the corneal incision group changed from preoperative astigmatism by 0.39 diopter at postoperative astigmatism by 0.39 diopter at postoperative day 1, 0.21 diopter at postoperative week 1, and 0.13 diopter at postoperative week 6. Mean vector astigmatism in the scleral incision group changed 1.26 diopters at 80 degrees at postoperative day 1, 1.05 diopters at 83 degrees at postoperative week 1, and 0.42 diopter at 103 degrees at postoperative week 6. Mean vector astigmatism in the corneal incision group changed 0.77 diopter at 90 degrees at postoperative week 1, and 0.61 diopter at 89 degrees at postoperative week 6. The differences were statistically significant (P = .003) only by vector analysis at the postoperative day 1 examination. We found significantly greater with-the-rule change in astigmatism in the scleral incision group than in the corneal incision group on the first postoperative day. The effect disappeared by the sixth postoperative week.

Endothelial Cell Loss After 3.5 mm Temporal Clear Corneal Incision and 3.5 mm Superior Scleral Tunnel Incision

OBJECTIVE: To undertake a comparative study of endothelial cell loss after 3.5 mm temporal clear corneal incisions (tCCI) and 3.5 mm superior scleral tunnel incisions (sSTI). STUDY DESIGN: Besides the site and preparation of the incision all 59 eyes were operated with the same surgical technique and implantation of a flexible silicone intraocular lens (IOL) through a 3.5 mm incision. In group 1 a temporal clear corneal incision and in group 2 a superior scleral tunnel incision were prepared. Endothelial cell density was measured preoperatively and 6 months after surgery with a contact specular microscope (Konan®). The results were compared and statistically analysed. RESULTS: Mean endothelial cell loss was 8.1% in group 1 and 3.0% in group 2. Even though relevant differences were found between the 2 groups, in statistical analysis the significance was ‘borderline’ (P < 0.0964). CONCLUSIONS: Even though CCI is a promising surgical technique with high beneficial influence on surgery and postoperative outcome, an increased central endothelial cell loss may be expected after surgery. Because of this fact, in the opinion of the authors, this technique should be avoided in cases with very hard cataracts and/or in cases with low preoperative endothelial cell density. As shown in the literature, when performing a CCI it is advisable to create the incision at the temporal site and not at the superior site which is close to the central corneal region.