Visual field changes after laser in situ keratomileusis in myopic eyes.

PURPOSE: To evaluate the effect of acute elevation of intraocular pressure (IOP) during laser in situ keratomileusis (LASIK) on the visual field in myopic eyes. SETTING: Istanbul University, Cerrahpassa Medical Faculty, Istanbul, Turkey. METHODS: Thirty-seven eyes of 37 patients were included in the study. The LASIK procedure was performed using the Hansatome microkeratome (Bausch & Lomb) and the Summit SVS Apex Plus 193 nm argon-fluoride excimer laser. Visual field testing was performed twice before LASIK and 1 day and 24 months after LASIK. Seventy-six points, 6 degrees apart, in the central visual field (Central 30-2) were tested for threshold sensitivity (Humphrey). The mean threshold sensitivity of baseline and post-LASIK visual field examinations was calculated in each patient. Seventy-six points of the Central 30-2 test were divided into 21 clusters corresponding to perimetric nerve-fiber bundles derived from Peridata software version 6.2a (Interzaag AG). The mean threshold sensitivity of each cluster and the visual field indices (mean deviation [MD] and corrected pattern standard deviation [CPSD]) in baseline and follow-up visual fields were compared using analysis of variance. RESULTS: The mean age of the 23 men and 14 women was 31.04 years +/- 6.55 (SD). The mean spherical equivalent refraction was -4.21 +/- 1.66 diopters (D) (range -2.25 to -6.75 D). The mean duration of suction was 42.29 +/- 29.06 seconds. The mean visual field sensitivity at baseline and the 2 follow-up examinations was 25.97 +/- 2.04 dB, 25.70 +/- 1.99 dB, and 27.17 +/- 1.68 dB, respectively (P =.181). There was no difference between preoperative and postoperative visual field clusters except in area 13. In area 13, threshold sensitivity was decreased at 1 day (P =.039) and at the preoperative level at 24 months. The MD of the visual fields was -3.53 +/- 1.67 dB, -3.61 +/- 2.91 dB, and -2.61 +/- 1.66 dB at the preoperative and 2 postoperative examinations, respectively (P =.495). The mean CPSD of the visual fields was 1.76 +/- 1.24 dB, 1.42 +/- 0.85 dB, and 1.74 +/- 0.86 dB, respectively (P =.680). CONCLUSION: Laser in situ keratomileusis did not cause visual field defects in mild to moderate myopic patients who had no risk factors that might render the optic nerve more vulnerable to damage.

Peripapillary serous retinal detachment preceding complete posterior vitreous detachment.

PURPOSE: To report on a case of peripapillary serous detachment due to vitreopapillary traction during the development of posterior vitreous detachment. METHODS: A 63-year-old female presented with acute decreased viual acuity and peripapillary serous retinal detachment extending to the macula in her left eye. Visual acuity was 20/200 in left eye and 20/20 in right eye. Optical coherence tomography confirmed the clinical findings. RESULTS: Peripapillary serous detachment resolved spontaneously 1 week after presentation with the complete development of posterior vitreous detachment. Visual acuity improved to 20/20. CONCLUSIONS: Posterior vitreous detachment may cause peripapillary and macular serous detachment during the development.

Lymphocyte subgroups and natural killer cell activity in recurrent herpetic stromal keratitis.

PURPOSE: Although the role of natural killer cells in the defense against certain viral infections has been published, little is known about the role of lymphocyte subgroups in recurrent herpetic stromal keratitis. Accordingly, serum levels of major immunoglobulins (IgG, IgA, and IgM) and IgG subgroups, the lymphocyte subgroups, and natural killer cell activity were investigated in patients with recurrent herpetic stromal keratitis. METHODS: Eleven patients with recurrent herpetic stromal keratitis and 10 healthy subjects were included. A delayed-type hypersensitivity skin test was performed in addition to the determination of serum immunoglobulin levels, IgG subgroups, peripheral blood lymphocyte percentages, and natural killer cell activity in both groups. RESULTS: The result of the delayed-type hypersensitivity skin test was positive in all patients with recurrent herpetic stromal keratitis and healthy subjects. No significant difference was obtained in serum immunoglobulin levels and IgG subgroups between the patients and healthy subjects. Among the cell surface antigens (CD3, CD4, CD8, CD16, CD19, and CD20), only CD8+ (i.e., cytotoxic) T-lymphocyte percentages were significantly increased (P=0.003), and the CD4:CD8 ratio was significantly decreased in the patients compared to the healthy subjects (P=0.021). There was no significant difference in the expression of CD16+ natural killer cells between both groups, despite a significantly lower natural killer cell activity in patients with recurrent herpetic stromal keratitis (P=0.011). CONCLUSIONS: These results indicate that human cytotoxic T cells show a difference in numbers and natural killer cell activity that may affect the prognosis of recurrent herpetic stromal keratitis.

Corneal topography in thyroid orbitopathy after orbital irradiation.

PURPOSE: The orbital tonus changes in thyroid orbitopathy, so it may be expected that corneal topographic results also change. Orbital irradiation may reduce the orbital tonus, and thus, it may affect the topographic changes. Corneal topographic results were examined before and after orbital irradiation in patients with thyroid orbitopathy to determine whether there was a difference. METHODS: Twenty eyes of 10 patients with thyroid orbitopathy were included in this study. Corneal topography was performed with Topographic Modeling System 2 (Tomey). The refractive power of the corneal curvature was measured at the center of the corneal apex and in each of the eight quadrants, 1.5 mm and 3 mm from the corneal apex, on the corneal topographer. A total dose of 20 Gy was given in 10 fractions over 2 weeks to the orbital structures sparing the lens, and corneal topography was performed 6 weeks and 8 months later. The measures of the refractive power of the cornea were taken again. Repeated-measures analysis of variance was used to evaluate the differences between the measures. RESULTS: There were no statistically significant differences in refractive power of the cornea in the topographic maps obtained before the radiotherapy and the two follow-up examinations after the radiotherapy. CONCLUSIONS: Thyroid orbitopathy is an orbital disease and may affect corneal topographic results. Orbital irradiation reduces or eliminates pathogenic orbital lymphocyte infiltration, thereby reducing orbital and extraocular muscle edema in patients with thyroid orbitopathy. In the current study group, corneal topographic changes were observed minimally as a result of the orbital irradiation, but they were not statistically significant.

Foveolar choroidal blood flow in idiopathic macular hole.

PURPOSE: To measure choroidal blood flow from foveal region in the eyes with idiopathic macular hole. METHODS: Thirteen patients with macular hole and 20 age-matched healthy subjects were included into the study. While group 1 consisted of 13 eyes of idiopathic stage 4 macular hole, seven fellow eyes of the same patients with stage 1a macular hole formed the group 2. The control group (group 3) comprised the randomly selected eye of 20 age-matched healthy subjects. Mean values of blood perfusion parameters that were composed of volume, flow and velocity, were recorded from foveal region of fundus using Heidelberg Retinal Flowmeter (HRF). The differences between the three groups were compared with unpaired t-test, Wilcoxon Signed Rank and Fisher's Exact test using statistical package program. RESULTS: The mean blood volume and velocity in the eyes with stage 4 macular hole (group 1) and in the eyes with stage 1a macular hole (group 2) were both significantly lower than the eyes in control eyes (group 3) (p < 0.05, unpaired t-test). Although, the mean blood "flow" parameter of group 2 was significantly lower than group 3 ( p < 0.05, unpaired t-test), there was no statistical difference in the "flow" parameter between group 1 and group 3 (p > 0.05, unpaired t-test). The comparison between group 1 and group 2 revealed no significant difference in any perfusion parameter (p > 0.05, Wilcoxon Signed Rank Test). CONCLUSION: Although, it may be result of macular hole, not necessarily the cause of it, these findings suggest that the eyes with idiopathic macular hole are associated with reduced foveolar blood flow. The measurement of the foveolar blood flow from choriocapillaris may be useful for identifying the subjects who have increased risk of development of macular hole in future. The study showed the association of a decrease in foveolar choroidal blood flow in eyes with idiopathic macular hole using HRF. Authors suggested that quantitative measurement of foveolar choroidal blood flow may be helpful for identifying the subjects who have increased risk of development of idiopathic macular hole.

Microbiologic evaluation of frequent-replacement soft contact lenses.

PURPOSE: This article reports a microbiologic study of two kinds of monthly frequent-replacement daily wear soft contact lenses, with different amounts of water content, in asymptomatic contact lens wearers. METHOD: We studied 35 lenses of 18 patients who wear frequent-replacement soft contact lenses with a water content of 38% and 40 lenses of 20 patients using frequent-replacement contact lenses with a water content of 55%. The lenses worn by patients regularly for 1 month were removed from their eyes in a sterile manner on the 30th day and were studied microbiologically to isolate pathogenic agents. RESULTS: In the group of monthly frequent-replacement soft contact lenses with a water content of 38%, microorganisms were isolated at a rate of 91%; and in the group of monthly frequent-replacement soft contact lenses with a water content of 55%, microorganisms were isolated at a rate of 85%. When the two groups were compared, there was no statistically significant difference (P=0.31). Although coagulase-negative staphylococci, Corynebacterium spp, and gram-negative rods were detected in both groups, Staphylococcus aureus, non-hemolytic streptococci, Neisseriae spp, and Penicillium spp also were isolated in the group with the higher water content. CONCLUSION: Bacteria spreading from the environment or from skin flora to the eyes showed more diversity in the group of frequent-replacement soft contact lenses with a high water content. Additionally, Penicillium spp also was isolated in this group. Therefore scrupulous attention to daily lens care is crucial for people who wear frequent-replacement soft contact lenses.