The Effect of Fluorescein and Indocyanine Green on Corneal Endothelial Function

Both sodium fluorescein[FL] and indocyanine green[ICG] were used for fundus angiography. Recently, these were also used during cataract surgery for enhancement of capsular visualization in white mature or hypermature cataract. So, ICG and FL may influence corneal endothelial function if left in anterior chamber. To evaluate the effect of intracameral FL or ICG on corneal endothelial function, rabbit corneas were isolated &mounted in the in-vitro specular microscope for endothelial perfusion. Experimental corneas were perfused with different concentrations of FL or ICG. Control corneas were perfused with glutathione-bicarbonate Ringer solution[GBR]. Corneal thickness was measured every 15 minutes during the perfusion and corneal swelling rates were calculated. Corneal endothelial permeability[Pa c] was measured according to the method of Watsky et al. The corneas perfused with FL, 2.5% deswelled probably due to high osmolarity. Swelling rates of corneas perfused with 1% and 0.5% FL did not differ significantly from control[p>0.05]. The corneas perfused with 0.01%, 0.005%, 0.002%, and 0.001% ICG swelled significantly[p0.05]. Pa c in corneas perfused with ICG, 0.005% increased markedly compared to control while corneas perfused with FL, 1% showed decreased permeability. The results of this study showed that FL did not affect endothelial function of rabbit cornea in relatively high concentrations while ICG affected endothelial function even in lower concentrations. With respect to clinical use of intracameral ICG, close attention must be paid.

Comparison of Automated Lamellar Keratoplasty with Laser Assisted In Situ Keratomileusis in Correction of High Myopia Over -11.00D

In order to compare the clinical results of Automated Lamellar Keratoplasty with Laser Assisted In Situ Keratomileusis for corection of high myopia, the effects of the procedure on 9 patients(10eyes) following ALK and 14 patients(15 eyes) following LASIK who were followed up at least 6 months were analyzed retrospectively. Mean preoperative spherical equivalent(S.E) was -17.32D(-11.50D~-22.50D) in ALK group and -16.05D(-12.00D~-24.00D) in LASIK group, while mean postoperative S.E was -3.19D at 1 week, -3.50D at 1 month, -4.12D at 3 months, -3.83D at 6 months in ALK group and +2.10D at 1 week, 0.70D at 1 months, -0.10D at 3 months, -0.58D at 6 months in LASIK group. Mean preoperative uncorrected visual acuity was 0.03 in ALK group and 0.04 in LASIK group. At postoperative 6 months, mean uncorrected visual acuity was improved to 0.18 in ALK group and 0.52 in LASIK group. The percentages of patients achieving correction within +/-1.00D at 6 months were 20% in ALK group and 47% in LASIK group. Postoperative cylindrical change was not significant in each group(p>0.05) and also best corrected visual acuity did not show statiscally significant changes in each group(p>0.05). The complications included folds of corneal flap, increased IOP, night halo, and corneal haze. In conclusion, ALK, when performed for high myopia with Ruiz normogram, resulted in undercorrection. LASIK seems to be much more predictable and accurate than ALK in high myopia.

Factors Affecting the Visual Outcome after Successful Retinal Reattachment Surgery in Rhegmatogenous Retinal Detachment Involving the Macula

To investigate the factors affecting the visual outcome after otherwise successful retinal reattachment surgery in rhegmatogenous retinal detachment involving macula, we performed a retrospective surgvey on 170 eyes encountered properly for this study. Preoperative variables used in this series included age of patients, duration of macular detachment, preoperative visual acuity, extent of detached retina, distance between breaks, and number, shape and location of breaks. We achieved visual acuities of 20/50 or better in 49% (83 of 170 eyes) after retinal reattachment surgery. Factors related to the favorable visual outcome (20/50 or better) were macular detachment lasting less than one month, preoperative visual acuities of 20/200 or better, extent of retinal detachment of 3Q or less, and detachment with tears located at or anterior to the equator. There was no relationship between the visual outcome and the type and the number of the breaks. Of all these variables, preoperative visual acuity has the closest correlation with the final visual results after anatomically successful reattachment surgery.

Management of Vitreous Floaters with Neodymium-YAG Laser

After Neodynium(Nd)-YAG laser photodisruption for vitreous floaters which were annoying the central visual field in 28 patients(28 eyes), we evaluated the efficacy of the procedure and the satisfaction degree of patients. Vitreous floaters were not recognized in 46 percents(13 eyes) of the patients, stayed away from the central visual field in 32 percents of the patients(9 eyes). Broken opacities were moved to retina in 22 percents(6 eyes) after treatment. In satisfaction degree of patients, 64 percents of the patients(18 eyes) were completely satisfied, 25 percents of them(7 eyes) were fairly satisfied, and 11 percents of them(3 eyes) were not satisfied at all. Complaints of unsatisfied patients were persisting floaters in 5 eyes, increased number of the floaters in 3 eyes and central visual field disturbance in 2 eyes. The responsible factors for failure in treatment were the size of the floaters larger than 2/3 disc diameter(DD), their locations closer than 2DD from retinal surface and their peripheral locations. Complications included the fragment shifting to posterior central zone in 2 eyes and the chorioretinal damage in 2 eyes. Our results suggest that Nd-YAG laser photodisruption seems to be useful on the discrete vitreous floaters less than 1/3DD in size and apart from retinal surface more than 2DD.

The Effect of Corneal Edema on Corneal Topography

To evaluate the changes in corneal topography following contact lens-induced corneal edema, sixty eyes of 30 patients that had never worn contact lenses were examined. A contact lens with very low oxygen transmissibility was placed over each cornea to induce corneal edema. The changes in corneal thickness, refraction, keratometry and topography were measured before and after subjects had been wearing hydrogel contact lens for 2 hours. The mean change in corneal thickness was 43.60 +/- 7.87 microgram from 542.90 +/- 22.89 microgram before contact lens wear to 586.50 +/- 23.19 microgram after contact lens wear (p=0.0000). Refracive change in vertical meridian was 0.1D increasing from -4.09D to -4.19D after contact lens wearing (p=0.0002), and there also was a small change in refractive errors in horizontal meridian decreasing from -3.45D to -3.34D (p=0.0000). There was a tendency toward with-the-astigmatism, because corneal curvature and Sim K value also increased in vertical meridian and decreased in horizontal meridian. These results suggest that contact lens-induced corneal edema may influence the corneal configuration in some degree, however, these changes does not seem to be clinically significant.