Influence of Lens Opacity on Nerve Fiber Layer Analysis in Glaucomatous and Normal Eyes

PURPOSE: To analyze the retinal nerve fiber layer in glaucoma eyes and in normal eyes, before and after cataract surgery using GDx (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A), - a scanning laser polarimetry, and to evaluate the effect of lens opacity on retinal nerve fiber layer analysis. METHODS: Ocular examination and GDx analysis were performed one month before and after cataract surgery on 16 eyes of 10 patients affected with glaucoma and 14 normal eyes of 9 patients at St. Mary's Hospital. Regarding the eyes affected with glaucoma, only those who showed no evidence of glaucoma progression on a visual field examination before and after the cataract surgery were included, and every cataract surgery was performed perfectly. Comparisons of the GDx parameters before and after cataract surgery were performed using the Wincoxon signed rank test. RESULTS: All GDx parameters before and after cataract surgery in normal eyes showed no significant differences. In the glaucoma patients, differences in symmetry (p=0.047), superior ratio (p=0.007), ellipse modulation (p=0.001), and GDx number (p=0.008) were statistically significant. CONCLUSIONS: GDx is an examination based on the birefringent nature of retinal nerve fiber layer so the values can change according to changes in the cornea and lens, which are birefringent. This study compared the GDx parameters before and after cataract surgery of glaucoma patients and normal eyes. Our results showed that lens opacity has a minor and subtle effect on GDx parameters, and indicated the most sensitive parameters that reflect the change of retinal nerve fiber layer. Further studies should be performed using a larger sample with statistical support.

Results of Combined Procedures versus Two-Stage Operation using Small Incision in Patients with Cataract and Glaucoma

To compare the result of small-incision combined procedure with that of two-stage procedure, the authors retrospec- tively reviewed 21 patients (23 eyes) who underwent small-incision combined cataract and glaucoma surgery (group 1) and 21 patients (23 eyes) who underwent small-incision cataract surgery after trabeculectomy (group 2). Intraocular pressure (IOP), visual acuity, bleb status, antiglaucoma medications and complications were analyzed.The mean follow-up period was 12.9 (2.3~30.1) months in group 1 and 13.9 (2.1~35.9) months in group 2. The mean preoperative IOP was 21.1 +/-6.6mmHg in group 1 and 26.6 +/-9 .3 mmHg in group 2. The mean postoperative IOP was 14.3 +/-3 .7 mmHg and 15.8 +/-3.1 mmHg in group 1 and 2, respectively. At last visit,13 eyes (56.5%) in group 1 and 12 eyes (52.2%)in group 2 had functioning blebs, and 21 eyes (91.3%) in group 1 and 17 eyes (73.9%) in group 2 had well controlled postoperative IOP without antiglaucoma medications.Rupture of posterior capsule,bleb site leakage, hypotony occurred in both groups; button hole (1 eye in group 1) and hyphema (2 eyes in group 2) were observed. These results indicate that the small-incisioncombined cataract and glaucoma surgery may be as safe and effective as the two-stage procedure.

Effect of Cataract Surgery through Clear Corneal Incision in Glaucomatous Eyes with Filtering Blebs

The small-incision cataract surgery by phacoemulsification with foldable posterior chamber lens implantation have recently permitted new options for combined trabeculectomy with cataract extraction. In the present study, we performed phacoemulsification and foldable intraocular lens implantation using small clear corneal incision in 20 patients with 22 glaucomatous eyes who had previously undergone trabeculectomy and determined its effects on visual acuity, intraocular pressure, the number of medications applied, and status of the filtering blebs. The mean follow-up period was 10.1 months and the mean time interval between the two surgeries was 14.7 months. The mean best corrected visual acuity was 0.19 preoperatively and 0.60 postoperatively and the postoperative visual acuity had improved in 19 eyes(86.4%). The mean(+/-standard deviation, SD) preoperative IOP was 16.7+/-5.88 mmHg and the mean(+/-SD) postoperative IOP at final visit was 15.5+/-4.07 mmHg. Postoperatively, the IOPs remained well controlled in 20 eyes(90.9%) without additional ocular hypotensives and required additional medications for control in 2 eyes(9.09%). And the funictioning bleb failures occurred in 5 eyes(22.7%). We found the procedure to be effective in restoring vision while controlling intraoperative pressure and preserving the filtering blebs.

Comparison of Transconjunctival Releasable Sutures and Transcorneal Releasable Sutures in Trabeculectomy

Releasable suture was used to control anterior chamber depth and intraocular pressure during early postoperative period following trabeculectomy. Failure of releasable suture removal was due to entrapping of the tissue into suture knot or fibrosis between suture and surrounding tissues. Hence, the authors compared the failure rate of transconjunctival releasable suture and transcorneal releasable suture in trabeculectomy. The authors evaulated the 60 eyes of 60 patients undergoing trabeculectomy. Of these eyes, 30 eyes did not use Mitomycin C and transconjuctival releasable suture(15eyes) and transcorneal releasable suture(15eyes) at 2weeks after trabeculectomy, and the other 30 eyes used Mitomycin C and were removed transconjuctival releasable suture(15eyes) and transcorneal releasable suture(15eyes) removed at 4 weeks after trabeculectomy. With Mitomycin C, failure rate of releasable suture removal was 87% in transconjunctival releasable suture and 33% in transcorneal releasable suture. Without Mitomycin C, failure rate of releasable suture removal was 73% in transconjunctival releasable suture and 7% in transcorneal releasable suture. Recently, we have commonly used thin suture material such as 10-0 nylon and with use of antimetabolite let releasable suture was removed at late time. We suggest that transcorneal releasable suture can reduce the fibrosis of subconjunctival tissue and reaction between suture material and subconjunctival tissue.

Comparison of Corneal Astigmatism after Keratolasty with 3 Kinds of Suture Techniques

In order to evaluate the comparison of corneal astigmatism after keratoplasty with 3 kinds of suture techniques, penetrating keratoplasty was performed in 25 patients(25 eyes) with different suture techniques, single continuous(group I, N=7), interrupted(II, N=7), and combined sutures(III, N=11) with 10-0 nylon. In group I, suture control was made from postoperative 1 month and selective suture removal was done in group II and III. The corneal astimatism was analyzed prospectively with corneal topography more than 1 year in all except 2 patients. The amout of corneal astigmatism in group I, II and III at postoperatie 1 month was 2.12D, 3.14D and 3.08D respectively (P>0.05, Kruskal-Willis test) and showed marked reduction upon postoperative 3 months. At postoperative 1 year, corneal astigmatism of each group was 2,62D, 1.49D and 2,18D respectively(P>0.05). The corneal astigmatism between keratoconus and other corneal disorders was not statistically ignificant. Interrupted suture induced least corneal astigmatism after keratoplasty compared to other suture methods even if there was no statistical significance.

Results of Phacoemulsificatin with PCL Implantation in Post-trabeculectomy Eyes

We evaluated the clinical results of phacoemulsification and posterior chamber lens implantation in posttrabeculectomy eyes. 26 eyes operated during Jan. 1990 to Dec.1995 were evaluated retrospectively with preoperative and postoperative visual acuity, intraocular pressure(IOP) and antiglaucomatous agent usage.The cataract operations were done by clear corneal incisions avoiding the filtering bleb sites. The average interval between trabeculectomy and cataract surgery was 25 months. From a total of 26 eyes 11 had the diagnosis of primary open angle glaucoma(POAG) and 12 eyes chronic angle closure glaucoma(CACG). The preoperative visual acuity was 0.3 or less in 53.8%, and the postoperative visual acuity was 0.4 or better in 57.7%. The preoperative and postoperative IOPs were 14.4+/-4.3mmHg and 15.3+/-4.6mmHg respectively, showing a slight increase. Filtering bleb failure was observed in one eye in which trabeculectomy was formed twice. Antiglaucomatous agent usage decreased to 8 cases from an initial 10 cases. The preoperative IOP of the 8 cases was 17.3+/-5.1mmHg, while it was 13.1+/-3.3mmHg in the 18 cases in which the IOP was controlled without treatment. There was a significant difference between the two(P=0.03). There was a significant relationship between preoperative and postoperative antiglaucomatous agent usage(P=0.01). Taken individually, POAG showed a greater incidence of postoperative antiglaucomatous agent usage than CACG, but was insignificant(P=0.56).

A Clinical Study of Risk Factors of Graft Rejection for Penetrating Keratoplasty

Penetrating keratoplasty was performed on 185 eyes. We analyzed the relative risk about the high and low risk groups, sex, age, complication, neovascularization, and graft size. In 185 grafts, graft rejection was developed in 60 eyes(32.4%). In the low risk group, there was the most graft rejection in 17 keratoconus eyes(62.9%) and in the high risk group, in 18 eyes with vascularized corneal scar. Graft rejection was developed in 33 eyes(47.8%) of the high risk group and developed in 27 eyes(23.3%) of the low risk group. The high risk group increased the risk of graft rejection(Relative risk=3.022, P value=0.001). Graft rejection developed in 33 eyes(25%) with non-vascularization and in 27 eyes(52%) with neovascularization. Neovascularization increased the risk of graft rejection (Relative risk=3.273, P value0.5). Mean preoperative visual acuity was 0.048 and mean postoperative visual acuity was 0.4. In the high risk group the mean postoperative corrected visual acuity was 0.25 and in the low risk group it was 0.5.