| Home Features Departments News & Trends  |
Short Takes Diopexy not An ImprovementDuring surgery for rhegmatogenous retinal detachment without significant preoperative proliferative vitreoretinopathy, diopexy and cryotherapy yield similar results, according to a prospective, randomized, 120-patient Australian study.All subjects underwent a scleral buckling procedure and treatment with either a transscleral diode laser or cryotherapy. Researchers designated the primary outcome measure as complete retinal reattachment at six months after a single operation. For the secondary outcome measure, they looked at postop pain and swelling, visual acuity, the occurrence of cystoid macular edema (CME), macular epiretinal membrane and pigment migration under the fovea at three months. Investigators found no statistically significant difference in the primary or secondary outcome measures between the subject groups. They report a primary success rate of 83 percent vs. 92 percent in the diopexy and cryotherapy groups, respectively. Via  angiography, they found CME in 12 percent of the diopexy group and
14 percent of the cryotherapy group. Researchers further report equivalent pain
and swelling one day postop. They found that 54 percent of patients in each
group attained visual acuity of at least 20/40, and they report a rate of
proliferative vitreoretinopathy in 5 percent in the diopexy group vs. 3 percent
in the cryotherapy group. According to a recent study, diopexy (above) and cryopexy produce similar outcomes in surgery for rhegmatogenous retinal detachment where there is no significant proliferative vitreoretinopathy preop. (Retina 2000;20:4:346-57) David H.W. Steel, FRCOphth, James West, FRCS, FRCOphth, William G. Campbell, FRACS, FRACO, FRCOphth Inflammation Reduction The implantation of heparin-surface-modified polymethlymethacrylate (PMMA) intraocular lenses (IOLs) results in less postoperative inflammation than does the implantation of PMMA IOLs that are not heparin-surface-modified. So finds a randomized, double-masked, multi-center, 367-patient U.S. study, supported in part by Pharmacia & Upjohn. Subjects consisted of 220 routine, 58 glaucoma and 89 diabetic patients. Investigators performed phacoemulsification in 94 to 98 percent of subjects; the others underwent extracapsular cataract extraction. Researchers implanted the same model PMMA lens in all subjects, with 183 receiving heparin-surface-modified IOLs. Follow-up continued for one year, and investigators defined postop inflammation as the presence of giant cells on the lens surface (as seen with specular micrography) and cellular deposits (as seen during slit-lamp examination). Researchers found statistically significantly fewer giant cells in the group that received heparin-surface-modified IOLs than in those who did not, but the difference occurred at different times in the different patient sub-groups. They observed the difference in routine patients at all follow-up examinations except that for one year, in glaucoma patients only at three months, and in diabetic patients at all follow-up examinations. Similarly, researchers report significantly fewer cell deposits in subjects receiving heparin-surface-modified IOLs: at the third-month examination in routine and diabetic patients and at the third- and sixth-month exams in glaucoma patients. (Ophthalmology 2000;107:6:1031-7) Stefan D. Trocme, MD, Hung-ir Li, PhD, for the Heparin-Surface-Modified Lens Study Group LASIK Affects RNFL LASIK significantly affects the retinal nerve fiber layer (RNFL), suggests a prospective, 35-eye Chinese study. Using a scanning laser polarimeter, a single investigator examined a consecutive series of patients before and one month after they underwent LASIK. Researchers formulated their measurements and calculations in terms of integrals and averages. They defined an integral as the area beneath the curve of peripapillary nerve fiber layer thickness, which lies along the ellipse surrounding the optic nerve head. They state that it is representative of the volume of the RNFL, while the average represents the average of all of the NFL thickness values on that curve. Researchers found a statistically significant difference in patients’ pre- and postoperative RNFL values. They report that the mean total integral of the RNFL was 0.59 ± 0.077 mm2 preoperatively vs. 0.549 ± 0.066 mm2 postoperatively. They found that the mean average of total RNFL thickness decreased from 80.17 ± 11.35 µm to 72.41 ± 9.24 µm. The authors note that it is not yet known how LASIK affects RNFL-thickness measurements themselves, and they call for larger studies. (Retina 2000;20:4:342-5) Yi-Yu Tsai, MD, Jane-Ming Lin, MD Laser Phaco Effective Erbium laser phaco works well on lenses with mild to moderate nuclear sclerosis, indicates a 40-eye, prospective, German pilot study. A single surgeon performed all the operations using Aesculap-Meditec’s MCL-29 erbium laser and a divide-and-conquer technique. He employed a clear corneal incision in 30 eyes and a corneoscleral tunnel in 10 eyes. Primary outcome measures included the ability to emulsify the lens nucleus and the occurrence of side effects. Researchers defined secondary outcome measures as the change in visual acuity, refraction, intraocular pressure (IOP), corneal thickness and endothelial cell density. The investigators report complete emulsification of the lens nucleus in 36 eyes (90 percent), all of which were rated grade zero through three for nuclear sclerosis. They found a mean phacoemulsification time of three minutes and a median total applied energy of 38.5 J. Researchers report postop changes in visual acuity, refraction and IOP comparable to those with ultrasonic phaco, in addition to an insignificant decrease in endothelial cell density. They state that three eyes experienced posterior capsule ruptures early in the series, but add that no other vision-threatening complications occurred. (Ophthalmology 2000;107:6:1053-62) Helmut Höh, MD, Evalies Fischer, MD First-line Therapy Evaluated Brimonidine is an effective alternative to timolol as a first-line therapy for glaucoma and ocular hypertension, and it has a less chronotropic effect on the heart. These were the findings of a 219-patient, prospective, multicenter, randomized, double-masked clinical effectiveness trial sponsored by Allergan. Researchers randomly assigned 111 patients to receive brimonidine 0.2% and 108 to receive timolol 0.5%. None of the subjects had previously undergone treatment with ocular hypotensive medication. Patients instilled a single drop of their assigned medication twice daily over the course of four months. Investigators assessed clinical success based on a reduction in intraocular pressure, safety and the occurrence of adverse events. They evaluated quality of life via the SF-36 Health Survey and the Glaucoma Disability Index. The researchers report similar rates of clinical success with both treatments, 71 percent with brimonidine and 70 percent with timolol. They found an overall mean decrease in IOP of 6.5 mmHg with brimonidine and 6.2 mmHg with timolol. They state that no significant chronotropic effects occurred in patients receiving brimonidine; they did observe a small but significant decrease in mean heart rate in the timolol group, however. The investigators report relative stability of mean systolic and diastolic blood pressure in both groups, and they report similar stability in quality of life for the groups. The authors emphasize that, unlike timolol, brimonidine is not contraindicated in patients with pulmonary or cardiovascular disease. (J Glaucoma 2000;9:3:224-34) Jonathan C. Javitt, MD, MPH, Rhett M. Schiffman, MD, MS |