Flap tearing during lift-flap laser in situ keratomileusis retreatment.

A flap tear occurred during laser in situ keratomileusis (LASIK) retreatment using a flap-lifting technique in 1 eye of 2 patients 4 to 5 months after the primary procedure. In the first case, the tear occurred in a decentered, standard thickness flap (168 mum) in a location close to the corneal limbus and limbal vessels. In the second case, the tear occurred in a well-centered thin flap (116 mum) that involved a peripheral corneal pannus. The false track was identified early, and central extension of the tear was averted. After the flap was successfully dissected, retreatment was performed without further complications. This report suggests that flaps with margins near the limbus or a corneal pannus may be prone to an earlier and stronger healing process at the edge that may lead to a flap tear during LASIK retreatment. This may be of increasing importance because of the trend toward larger flap diameters.

Using optical coherence tomography to monitor photodynamic therapy in age related macular degeneration.

PURPOSE: To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularization (CNV) activity before and after photodynamic therapy (PDT) in patients with age-related macular degeneration (ARMD). DESIGN: Prospective observational case series. SETTING: Institutional study. patient population: Fifty-three patients (62 eyes) with ARMD. OBSERVATION PROCEDURE: Prospective observational case study. MAIN OUTCOME MEASURES: Presence or absence of leakage on fluorescein angiography, presence of intraretinal or sub-retinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT. RESULTS: The macular thickness decreased significantly after PDT (P = .001). However, no significant changes in CNV thickness were measured after PDT (P = .567). Once the diagnosis of ARMD was established before treatment, OCT had a sensitivity of 96.77% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.65%) and a moderate specificity (59.01%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 82.95%. CONCLUSIONS: OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with ARMD.

Retinal thickness study with optical coherence tomography in patients with diabetes.

PURPOSE: To quantitatively assess retinal thickness by optical coherence tomography (OCT) in normal subjects and patients with diabetes. This study was intended to determine which retinal thickness value measured with OCT best discriminates between diabetic eyes, with and without macular edema. METHODS: OCT retinal thickness was measured by a manual technique in a total of 26 healthy volunteers (44 control eyes) and 85 patients with diabetes (148 eyes) with the clinical diagnosis of no diabetic retinopathy (45 eyes), nonproliferative diabetic retinopathy without clinically significant macular edema (CSME; 54 eyes), proliferative diabetic retinopathy without CSME (21 eyes), and 28 eyes with diabetic retinopathy with CSME. Independent predictors of the presence of CSME were quantified by using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were generated to evaluate and compare the predictor variables. The correlation of retinal thickness measurements and visual acuity was calculated. RESULTS: There were statistically significant differences in foveal thickness between control eyes and all the other eye groups (P = 0.001). Diabetic eyes with CSME had a statistically significant greater thickness in each of the areas compared with the other groups. In a multivariate logistic regression model, foveal thickness was a strong and independent predictor of CSME (odds ratio [OR], 1.037; 95% confidence interval [CI] 1.02-1.05). The area under the ROC curve of this predictor variable was 0.94 (P = 0.001). For a cutoff point of 180 microm, the sensitivity was 93%, and specificity was 75%. Foveal thickness correlated with visual acuity in a log minimum angle of resolution (logMAR) scale (Spearman's rho = 0.9, P = 0.001). CONCLUSIONS: These results suggest that foveal thickening over 180 microm measured by OCT may be useful for the early detection of macular thickening and may be an indicator for a closer follow-up of the patient with diabetes.