A. Lleó-Pérez

Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherence tomography in normal and ocular hypertensive subjects.

Purpose To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. Methods Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. Results In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nevertheless, the test–retest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). Conclusions Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better test–retest correlation.

Assessment of applanation tonometry after hyperopic laser in situ keratomileusis.

Purpose. To determine the reliability and identify pitfalls in intraocular pressure measurement by Goldmann applanation tonometry after hyperopic laser in situ keratomileusis (LASIK). Methods. Prospective non-masked case series at University of Valencia, Faculty of Medicine and Rahhal Ophthalmology Clinic, Valencia, Spain. One hundred three patients (103 eyes) treated with hyperopic LASIK were evaluated. The main treatment was hyperopic LASIK using a microkeratome Chiron Hansatome (Chiron Vision Corp, Claremont, CA) and the excimer laser Chiron Technolas 217-C LASIK (Chiron Technolas GmbH, Dornack; Germany). Central Goldmann applanation tonometric readings before surgery and 1, 3, and 6 months after surgery were analyzed. Results. After hyperopic LASIK, a significant decrease in intraocular pressure was observed in the postoperative controls. In the low hyperopia patients (range: 1.00–3.00 D) a decrease of 2.43 mmHg was observed at the 6-month follow-up (p < 0.001). In the moderate hyperopia group (range: 3.25–6.00 D) a decrease of 2.05 mmHg was observed at the 6-month follow-up (p < 0.001). There were no significant differences between low and moderate hyperopia (p = 0.812). There was no statistically significant correlation between the magnitude of decrease in tonometry and gender, age, treated spherical equivalent, pachymetry, and anterior chamber depth (ACD). Conclusions. This clinical study displays that postoperative tonometry after hyperopic LASIK was significantly lower than the preoperative, hence modifying the reliability of Goldmann tonometry, and causing an intraocular pressure underestimation. A correcting factor should be applied when using applanation tonometry to measure postoperative intraocular pressure in patients who have undergone hyperopic LASIK.

Anatomic study of the corneal thickness of young emmetropic subjects

Purpose To study the corneal thickness of young emmetropic subjects. Methods One thousand eyes of 1000 young healthy emmetropic subjects were analyzed with the Orbscan Topography System II (Orbscan, Inc, Salt Lake City, UT) from January 2001 to May 2003. The age of the subjects ranged from 20 to 30 years old (mean ± SD = 27.12 ± 2.86). The mean of 5 consecutive measurements of the corneal thickness in the center of the cornea and at temporal, superotemporal, inferotemporal, nasal, inferonasal, and superonasal cornea were recorded. Results The corneal thickness at the following areas ranged as follows: 518 to 589 μm center; 603 to 678 μm nasal; 620 to 689 μm superonasal; 600 to 669 μm inferonasal; 571 to 639 μm temporal; 601 to 669 μm superotemporal; and 572 to 647 μm inferotemporal. In each individual the difference between the central thickness and the maximum paracentral thickness ranged from 85 to 107 μm (mean ± SD, 99.21 ± 3.80). The difference between the central thickness and the minimum paracentral thickness ranged from 36 to 59 μm (48.97 ± 4.23 μm). The difference between the minimum paracentral corneal thickness and the maximum paracentral corneal thickness ranged from 37 to 58 μm (50.24 ± 4.30). The tonometry was statistically correlated with the corneal thickness (P < 0.05 at each corneal location analyzed). Conclusions In emmetropic corneas the difference between the minimum paracentral thickness and the maximum paracentral thickness was similar to the difference between the central thickness and the minimum paracentral thickness.

Quantitative anatomical differences in central corneal thickness values determined with scanning-slit corneal topography and noncontact specular microscopy

Purpose: This study was designed to analyze the differences in central corneal thickness values determined with noncontact specular microscopy and scanning-slit corneal topography. The measurements were performed on the same eye. Methods: We analyzed the central corneal thickness values of 93 patients (n = 93) by means of noncontact specular microscopy (Topcon SP-2000P noncontact specular microscope, Topcon Corp., Tokyo, Japan) and scanning-slit corneal topography (Orbscan Topography System II, Orbscan Inc., Salt Lake City, UT). One experienced physician performed 3 consecutive central corneal thickness measurements with both devices. Results: The central corneal thickness values obtained by means of Orbscan pachymetry were 17 ± 2.7 (range, 12-24) μm greater. A significant correlation was observed between scanning-slit corneal topography and noncontact specular microscopy (Pearson correlation coefficient, r = 0.976; P < 0.001). Conclusions: Researchers should know of the existence of this difference between noncontact specular microscopy and Orbscan pachymetry when interpreting central corneal thickness values.

Intraocular pressure in myopic patients after Worst-Fechner anterior chamber phakic intraocular lens implantation

PURPOSE To assess intraocular pressure measured with a Goldmann tonometer over a period of 1 year after implantation of a Worst-Fechner anterior chamber phakic intraocular lens to correct myopia of -7.00 D or more. METHODS We performed a prospective, non-masked study of 100 patients (100 myopic eyes) who had a Worst-Fechner phakic intraocular lens implanted to correct myopia of -7.00 D or greater. Central corneal Goldmann tonometry was performed before surgery and 1, 3, 6, and 12 months after surgery. The influence of different variables was assessed. RESULTS IOP showed a significant increase of a mean 2.1 mmHg at 3 months after surgery (P=.001). There was not a statistically significant difference between IOP before surgery and 6 months after PIOL implantation (P=.244) or 1 year after surgery (P=.845). In one eye, the lens was explanted 11 months after surgery because of the presence of ocular hypertension. No variables studied showed a statistically significant difference from before to after surgery. CONCLUSIONS Worst-Fechner anterior chamber phakic intraocular lens implantation led to a slight transitory increase of intraocular pressure during the first 3 months after surgery, but returned to preoperative levels by 6 months after implantation.

Inter‐observer variability of central corneal thickness measurements using non‐contact specular microscopy after laser in situ keratomileusis

Background: The aim of this study was to investigate the inter‐observer variability of central corneal thickness measurements carried out with a non‐contact specular microscope in patients who had undergone myopic laser in situ keratomileusis.

Goldmann tonometry after hyperopic laser in situ keratomileusis: comparison between retreated and nonretreated patients.

Purpose To identify differences in applanation tonometry between retreated and nonretreated eyes (primary LASIK eyes) 6 months after hyperopic laser in situ keratomileusis. Methods In a prospective study 100 eyes (100 patients) underwent conventional hyperopic laser in situ keratomileusis under a 160-μm flap. Central Goldmann applanation tonometry was determined before and 6 months after surgery in 78 (78%) primary LASIK eyes and before surgery and 6 months after the retreatment date in 22 (22%) retreated eyes. Results Preoperative mean tonometry was 14.96 ± 1.96 mm Hg and 15.30 ± 1.95 mm Hg in primary LASIK and retreated eyes, respectively. Six months after surgery it was 12.99 ± 2.03 mm Hg (P < 0.001) and 12.67 ± 2.20 mm Hg (P < 0.001), respectively. No significant differences in mean tonometry were found between retreated and primary LASIK eyes 6 months after surgery (P = 0.537). Decreased tonometric values were found in 20 retreated eyes (90.91%) and in 62 primary LASIK eyes (79.48%). Increased tonometric values higher than 1 mm Hg were found in 3 primary LASIK eyes (3.84%), but no retreated eyes showed increased values 6 months after surgery. Two retreated eyes (9.09%) and 10 primary LASIK eyes (79.49%) presented the same tonometric values before surgery and at the end of the study. Conclusions After hyperopic laser in situ keratomileusis there was no significant difference in Goldmann applanation tonometry between retreated and primary LASIK eyes.

Enhanced Oxidative Stress and Other Potential Biomarkers for Retinopathy in Type 2 Diabetics: Beneficial Effects of the Nutraceutic Supplements

We have studied the global risk of retinopathy in a Mediterranean population of type 2 diabetes mellitus (T2DM) patients, according to clinical, biochemical, and lifestyle biomarkers. The effects of the oral supplementation containing antioxidants/omega 3 fatty acids (A/ω3) were also evaluated. Suitable participants were distributed into two main groups: (1) T2DMG (with retinopathy (+DR) or without retinopathy (−DR)) and (2) controls (CG). Participants were randomly assigned (+A/ω3) or not (−A/ω3) to the oral supplementation with a daily pill of Nutrof Omega (R) for 18 months. Data collected including demographics, anthropometrics, characteristics/lifestyle, ophthalmic examination (best corrected visual acuity, ocular fundus photographs, and retinal thickness as assessed by optical coherence tomography), and blood parameters (glucose, glycosylated hemoglobin, triglycerides, malondialdehyde, and total antioxidant capacity) were registered, integrated, and statistically processed by the SPSS 15.0 program. Finally, 208 participants (130 diabetics (68 +DR/62 −DR) and 78 controls) completed the follow-up. Blood analyses confirmed that the T2DMG+DR patients had significantly higher oxidative stress (p < 0.05), inflammatory (p < 0.05), and vascular (p < 0.001) risk markers than the T2DMG−DR and the CG. Furthermore, the A/ω3 oral supplementation positively changed the baseline parameters, presumptively by inducing metabolic activation and ameliorating the ocular health after 18 months of supplementation.