The Analysis of Refractive Errors of AMO Array(R) Multifocal Intraocular Lens with SRK II Formula

PURPOSE: To evaluate the accuracy of the SRK II formula for the AMO Array(R) multifocal intraocular lens (Array lens) power calculation according to axial length. In case of refractive error more than +/- 1.0 diopter (D), we compared the accuracy of the SRK II with that of other formulas. METHODS: Participants were 178 eyes (142 patients) received the Array lens. These were divided into 3 subgroups based on axial length. Group I had 21 eyes of short axial length (less than 22.0 mm). Group II had 133 eyes of average axial length (more than 22.0mm below 24.5mm). Group III had 24 eyes of long axial length (more than 24.5mm). The difference between preoperative predicted refractive value and postoperative manifest refractive value were calculated. We compared the accuracy of the SRK II and that of SRK/T, Holladay formulas in case of refractive error more than +/- 1.0D. RESULTS: Three eyes (14.2%) in Group I, 14 eyes (10.5%) in group II and 15 eyes (62.5%) in Group III showed refractive errors more than +/- 1.0D. Fifteen eyes (62.5%) in Group III were significantly reduced to 7 eyes (29.1%) with using SRK/T, Holladay formulas. CONCLUSIONS: SRK II formula had better predictive accuracy in axial length less than 24.5mm with Array lens. But it is better to apply SRK/T or Holladay formulas when axial length is more than 24.5mm.

The Effect of Imatinib (Gleevec(R)) on The Proliferation of Lens Epithelial Cells and The Activities of Growth Factors

PURPOSE: To evaluate the effect of Imatinib which is tyrosine kinase inhibitor used for the treatment of chronic myelogenous leukemia on the proliferation of the lens epithelial cells and the activities of growth factors. METHODS: In the experimental group I, the cells were exposed to Imatinib for 3, 5 min with various concentration. In the experimental group II, the cells were cultured with PDGF, bFGF, TGF-beta2. In the experimental group III, the cells were exposed to Imatinib for 3, 5 min with the various concentration in the presence of each growth factor. The cell viability was assessed by MTT assay. And the cell proliferation were evaluated by BrdU staining. The phosphorylation of ERK (Extracellular-signal regulated kinase) and the amount of collagen type I produced by TGF-beta2 were analyzed with western blot. RESULTS: MTT assay showed that the viability of lens epithelial cells was decreased about 50% at the concentration above Imatinib 30 micro M for 5 mins exposure in group I. Both PDGF and bFFG induced significantly increased cell viability in group II. The group III that was treated with both PDGF and bFGF showed the decrease of cell viability after being exposed to Imatinib. As the concentration of Imatinib increased, BrdU incorporation of experimental group I was decreased compared with control group. It also found that The BrdU incorporation of experimental group III was also decreased compared with experimental group II. The phosphorylation of ERK 1/2 and the amount of collagen type I production was significantly decreased in addition of Imatinib 20 to 30 micro M for 3 mins exposure. CONCLUSIONS: The proliferation of lens epithelial cells could be inhibited by Imatinib. And the activities of PDGF, bFGF, TGF-beta2 were also inhibited by Imatinib.

Dapiprazole for the Reversal of Mydriasis

Some patients are very sensitive to glare after diagnostic mydriasis with tropicarnide or phenylephrine. It would be desirable to reverse the effects of mydriasis rapidly and safely after diagnostic mydriasis. We assessed the effect of topical dapiprazole, an alpha adrenergic receptor blocker, in reversing mydriasis in 40 dark brown Iris subjects who received tropicamide 1% or phenylephrine 2.5%. There was a significant difference in the decrease in pupil size between the eyes that received dapiprazole and the control eyes. This study suggests that dapiprazole 0.5% eye drops are effective and safe in reversing mydriasis after instilation of tropicamide 1% or phenylephrine 2.5% into dark brown irides.

Ultrastructural Study on Basement Membrane Thickening of Iris Capillaries in Diabetic Patients

The early ultrastructural changes of basement membrane thickening and degeneration of the pericyte were noted in retinal capillaries in diabetic patients. However no early ultrastructural changes were reported in diabetic iris capillary. The authors studied the ultrastructural features of basement membrane of iris capillaries which were obtained during cataract surgery in five diabetic patients and compared with those obtained in five nondiabetic patients. The endothelium basal lamina, pericyte basal lamina and membrane-like pericyte matrix in didabetic iris capillaries were thicker than those in nondiabetic Iris capillaries. The thickening of pericyte basal lamina is more prominant than the endothelium basal lamina in diabetes. The duration of diabetes had no relationship to endothelium basal lamina but, showed statistically significant relationship to thickness of pericyte bascal lamina and pericyte matrix.