Ultrastructure of the Internal Limiting Membrane Removed During Macular Hole and Diabetic Macular Edema Surgery

PURPOSE: To evaluate retinal damage following internal limiting membrane (ILM) peeling in macular hole and diabetic macular edema (DME) surgeries. METHODS: Forty-five eyes with macular holes and thirty-five eyes with DME underwent pars plana vitrectomy with ILM peeling. The structures of the ILM were investigated using transmission electron microscopy, and the grades of retinal tissue damage were analyzed. We additionally observed the clinicopathologic association of retinal damage with the development of retinal hemorrhage during ILM peeling and that seen with indocyanine green (ICG) staining. RESULTS: In all specimens, cellular fragments were observed on the retinal side of the ILM in both macular hole and DME patients. The thickness of the ILM in DME significantly increased (3.13+/-1.12 micrometer compared with that in patients with macular holes (2.41+/-0.77 micrometer, p=0.002). The frequency of minute retinal bleeding during ILM peeling was higher in macular hole patients (46.7%) than in those with diabetic macular edema (22.9%m p=0.028). Twenty-two eyes of 45 macular hole patients (48.9%) and 16 eyes of 35 DME patients (45.7%) had relative retinal damage. Overall, ILM performed in eyes which had minute bleeding during the peeling had more retinal damage (62.1%) than did those without hemorrhage (39.2%, p=0.049). ICG staining did not appear to influence retinal damage (p=0.81). CONCLUSIONS: ILM peeling can cause minor, but demonstrable, damage of the adjacent retina.

Acute Zonal Occult Outer Retinopathy Mimicking Retrobulbar Optic Neuritis

A 27-year-old woman suffered a sudden visual disturbance in the right eye. The right eye had a visual acuity of 0.02 and a relative afferent pupillary defect. A visual-field examination revealed an inferotemporal field defect in the right eye. A fundus examination revealed no abnormalities that were responsible for the visual-field defect. Multifocal electroretinography showed decreased responses in the right eye at the corresponding area with the visual-field defect. She was diagnosed as acute zonal occult outer retinopathy.

Comparison of Clinical Efficacy Between Tie Methods of Silicone Tube Intubation in Nasolacrimal Duct Obstruction

PURPOSE: To compare the clinical outcome of silicone tube intubation according to the tie methods. METHODS: Eighty-eight eyes of 87 patients who underwent silicone tube intubation were divided into two groups based on the tie method: a silicone silastic sheet group (Group 1, n=59) and a nylon 6-0 suture knot group (Group 2, n=29). The two groups were compared according to their success rates, recurrence rates and complications. RESULTS: No significant difference was found in the success rate between the two groups (83.0% in Group 1 and 82.7% in Group 2). However, Group 2 showed a significantly higher rate of postoperative complications than Group 1. In Group 1, 5/59 (8.4%) eyes had ocular irritation, 2/59 (3.4%) eyes exhibited tube prolapse, conjunctivitis, corneal erosion, and dacryocystitis and 1/69 (1.6%) eyes had a punctal slit after intubation. In Group 2, 3/29 (10.3%) eyes had ocular irritation, 2/29 (6.9%) eyes exhibited tube prolapse, conjunctivitis, a punctal slit, and dacryocystitis, and 1/29 (3.4%) eyes showed corneal erosion, or a granuloma after intubation. A recurrence of symptomatic tearing was found in 6/59 (10%) eyes in Group 1 and 3/29 (10%) in Group 2. CONCLUSIONS: In silicone tube intubation of incomplete NLD obstruction, the usage of silicone silastic sheets to tie both ends of the silicone tube produced a lower complication rate and a higher success rate than that of the suture knot group. Lower tension on the nasolacrimal passage in the silicone silastic sheet group allows for a significantly lower rate of punctal slit development. Therefore, the method of using silicone silasitic sheets can be considered useful in the treatment of NLD obstruction.

Confocal Microscopic Changes in the Cornea 10 Years After Photorefractive Keratectomy

PURPOSE: The present study compares, using a new generation high-resolution in vivo confocal microscope, the corneas of patients who underwent photorefractive keratectomy (PRK) 10 years previously with those of healthy persons. CASE SUMMARY: A confocal microscope (Confoscan 4.0, Fortune Technology, Italy) was used to get the data from healthy volunteers and patients. Corneal cross-sectional images of the epithelium, Bowman's layer, stromal layer (anterior, middle and posterior keratocyte), Descemet's membrane, and endothelium were compared. In PRK corneas, the superficial epithelium was nearly intact and the subbasal nerve plexus was visible, but some hyperreflective areas were also found in the nerve plexus. Because of the absence of the Bowman's layer, some ECM and keratocytes were visualized in their optical section. Although anterior keratocytes showed uneven distribution with less cellularity, middle and posterior keratocytes looked unaffected. Likewise, there were no differences in the endothelium between the two groups. CONCLUSIONS: Ten years after PRK, the subbasal nerve plexus and anterior keratocytes showed histologic changes after corneal wound recovery.

Analysis of Localized Retinal Nerve Fiber Layer Defects not Detected by Optical Coherence Tomography

PURPOSE: To analyze localized RNFL defect cases that were identified in retinal nerve fiber layer (RNFL) fundus photographs but not in optical coherence tomography (OCT). METHODS: Analysis of OCT scans and images was performed for 14 eyes (17 locations) that showed localized RNFL defects in RNFL fundus photographs but not in RNFL thickness average analysis. RESULTS: With respect to the range of RNFL defects, 41.2% were less than 10degrees, 47.0% were 11 to 20degrees, and 11.8% were 21 to 30degrees. In 71.4% of the RNFL cases the defects were less than 10degrees and the decrease of RNFL thickness was not readily observable on the OCT scan images. In all cases of RNFL defects in the 11 to 30degrees range the decrease in RNFL thickness could be assessed on the OCT scan images. Nonetheless, the decrease of RNFL thickness could not be seen on the OCT analysis images in which the results of the RNFL thickness made through an automated computer algorithm were displayed. CONCLUSIONS: The range of localized RNFL defects that were difficult to detect with OCT consisted of those cases that were almost less than 20degrees. The limitations of the OCT scan itself in patients with RNFL with an angular width defect less than 10degrees and the problems of RNFL thickness analysis processing in patients with an angular width of 11 to 30degrees may decrease the sensitivity of OCT in diagnosing RNFL defects.

Differences in Intraocular Pressure, Corneal Thickness, and Corneal Endothelium Related to Duration in Diabetes

PURPOSE: This study evaluated the differences of intraocular pressure (IOP), corneal thickness, and corneal endothelial morphology compared with age-matched, healthy control subjects, as well as the correlation according to the duration of diabetes. METHODS: Goldmann applanation tonometry, ultrasound pachymetry, and non-contact specular microscopy were performed in 200 patients with diabetes and 100 control subjects. RESULTS: The diabetic subjects had higher IOP, thicker cornea and less cell density, less hexagonality, and more irregular cell size of corneal endothelium than the controls (P<0.05). Central corneal thickness and coefficient of variation in cell size were higher in diabetes of over 10 years duration than in diabetes of under 10 years duration (P<0.05), while endothelial cell density and percentage of hexagonal cells were lower in the diabetes of over 10 years group (P<0.05). Central corneal thickness was correlated with duration of diabetes but IOP and corneal endothelial morphologic characteristics were not. CONCLUSIONS: Especially, those with a diabetes duration of over 10 years have more corneal morphological abnormalities and a higher IOP than normal subjects. Therefore, any surgical procedures should be performed carefully in the diabetic cornea that is easily damaged by, for example, phacoemulsification.

Treatment of Phlyctenular Keratoconjunctivitis with Oral Tetracycline in Recurrent Phlyctenulosis

PURPOSE: We succesfully treated two patients for phlyctenular keratoconjunctivitis which had recurrent episode or was not respond to steroid therapy, with oral tetracycline. METHODS: A 20-year-old girl (Case 1) was referred here because of a two-year history of recurrnet episode of phlyctenular keratoconjunctivitis. There was small pinkish nodule, about 2mm in diameter, and adjacent conjunctival injection in the temporal limbus in her left eye. Corneal opacity and superficial corneal vascularization was located inferiorly. A 12-years-old girl (Case 2) had been followed for 1 years with a recurrent vascularized corneal lesion and infiltration in the right eye. Cultures of the conjunctiva and eyelids were obtained. RESULTS: In case 1, topical steroid treatment led to some improvement but it was only temporarily. She was treated with oral tetracycline at an initial dose of 250mg three times daily for 3 weeks followed by 250mg once daily for 3 weeks. In case 2, doxycycline 100mg twice daily for 2 weeks and tapered 10mg once daily for 3 weeks. All patients experienced rapid relief of symptoms and long term remission of their disease after oral tetracycline or doxycycline treatment. CONCLUSIONS: Oral tetracycline treatment is safe and effective treatment for resistant and recurrent phlyctenular keratoconjunctivitis. In children younger than 10 years of age, doxycycline shluld be recommended alternatively because tetracycline can discolor the teeth.

Effect of Anti-inflammatory Mediator on the Proliferation of Human Corneal Keratocyte

PURPOSE: The purpose of this study was to evaluate the effect of anti-inflammatory mediators like dexamethasone, nordihyroguaratic acid (NDGA), and diclofenac sodium on proliferation of human corneal keratocytes, and to investigate the cellular morphology of keratocyte. METHODS: Human corneal keratocytes were exposed to 0.05, 0.1, 0.3, 0.8, and 1.0 mM concentration of each drug for period of 24, 48, and 72 hours. MTT based colorimetric assay was performed to assess the metabolic activity and inhibition of cellular proliferation. Cellular morphology was evaluated by inverted phase contrast micrograph and electron microscopy. RESULTS: The higher the concentration of inoculated each drugs was, the more the inhibitory effect of human keratocyte proliferation was found (P<0.05). NDGA, over 0.3 mM and diclofenac, more than 0.1 mM had significant more inhibitory effect on keratocyte proliferation compared with dexamethasone within 48 hours of exposure to each drug. With the concentration and exposure time of each drug, human corneal keratocytes were visible more rounded and swollen rather than spindle shape, and detached from the bottom of the dish. The damaged keratocytes had degenerative changes like cellular membrane disruption, microvilli disappearance, enlarged rough surfaced endoplasmic reticulum and mitochondria, vacuole formation and nuclear membrane damage by TEM. CONCLUSIONS: On basis of this study, the anti-inflammatory mediators such as NDGA and diclofenac sodium have less side effects and stronger inhibitory effects of human keratocyte proliferation than dexamethasone.