Melda Yenerel

Polymorphisms of the DNA repair genes XPD and XRCC1 and the risk of age-related macular degeneration.

PURPOSE Oxidative stress seems to be an important factor in the development of age-related macular degeneration (AMD). The role of DNA repair mechanisms has also received attention recently in AMD pathogenesis. This case-control study was conducted to determine the frequency of polymorphisms in two DNA repair enzyme genes, xeroderma pigmentosum complementation group D (XPD), codons 312 and 751, and x-ray cross-complementing group 1 (XRCC1), codons 194 and 399, in patients with AMD and in disease-free control subjects. METHODS Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to analyze XPD Asp312Asn and Lys751Gln and XRCC1 Arg194Trp and Arg399Gln in 120 patients with AMD (65 with dry type and 55 with wet type) and in age-matched 205 disease-free control subjects. RESULTS Genotypic and allelic distributions of the polymorphisms were detected. For the XPD polymorphism, although the allele frequencies were not different between the patients and healthy control subjects, there was a significant difference between frequencies for the XPD751 Gln/Gln genotype in AMD patients (9%) and healthy control subjects (19%; P=0.02). The XPD751 Gln/Gln genotype seemed to have a protective effect against development of AMD (odds ratio, 0.41; 95% confidence interval, 0.19-0.88). Stratification by subtype of AMD revealed that the XPD751 Gln/Gln genotype was significantly lower only in the patients with dry type (P=0.02). These interactions remained nearly significant after Bonferroni correction (P<0.0125). Haplotype analysis for the two XPD polymorphisms revealed that the haplotype GC (312Asp-(751)Gln) was a protective haplotype against AMD. No statistically significant difference was found for the genotypic and allelic distributions of the polymorphisms in the XRCC1 gene between the patients and the control subjects. CONCLUSIONS Polymorphism in XPD codon 751 may be associated with the development of AMD.

Assessment of Anterior Chamber Depth Using Visante Optical Coherence Tomography, Slitlamp Optical Coherence Tomography, IOL Master, Pentacam and Orbscan IIz

Aims: To assess and compare the anterior chamber depth (ACD) by different anterior segment imaging techniques. Methods: Eighty healthy eyes of 40 patients were recruited, and 3 consecutive measurements of ACD were determined prospectively utilizing Visante optical coherence tomography (OCT), slitlamp (SL) OCT, IOL Master, Pentacam and Orbscan IIz. The statistical significance of interdevice differences between measurements was evaluated by one-way ANOVA and Bland-Altman analysis. The repeatability of 3 consecutive measurements was analyzed by repeated-measures ANOVA. Results: The mean ACD was 2.98 ± 0.29, 2.85 ± 0.29, 3.33 ± 0.42, 2.93 ± 0.30 and 2.80 ± 0.29 mm with Visante OCT, SL-OCT, IOL Master, Pentacam and Orbscan IIz, respectively. All devices displayed a high intrasession repeatability (repeated-measures ANOVA, p > 0.05). ACD measurements obtained by the IOL Master were significantly greater compared to other devices. ACD values detected by Visante OCT and SL-OCT, Pentacam and Orbscan IIz were not clinically interchangeable, even though no statistically significant difference was detected. Conclusion: Although noncontact ACD measurements using all modalities were easy to handle and demonstrated good repeatability, the tested devices were not regarded as compatible. Hence, the clinician should take the different modalities into consideration during ACD assessment using various devices.

Glutathione S-Transferase M1, GSTT1 and GSTP1 Genetic Polymorphisms and the Risk of Age-Related Macular Degeneration

Purpose: To determine the possible effects of glutathione S-transferase (GST) M1, GSTT1 and GSTP1 genetic polymorphisms on the risk of developing age-related macular degeneration (AMD). Patients and Methods: This case-control study included a total of 120 patients with AMD (65 with dry-type AMD and 55 with wet-type AMD) and 198 disease-free controls. GSTM1 and GSTT1 polymorphisms were analyzed by using a multiplex polymerase chain reaction (PCR), and GSTP1 polymorphism was detected by real-time PCR assay. Results:GSTM1-null genotype was significantly associated with the development of AMD (p = 0.01, OR = 1.82, 95% CI = 1.14–2.91). Stratification by AMD subtypes revealed a significant relationship between GSTM1-null genotype and dry-type AMD (p = 0.02, OR = 1.98, 95% CI = 1.10–3.53). In a stepwise regression model, only GSTM1-null genotype was significantly associated with the development of AMD (p = 0.01, OR = 1.77, 95% CI = 1.11–2.81). Conclusions: Our findings suggest that genetic polymorphisms of GST may have a role in the development of AMD.

Fundus autofluorescence in acute and chronic central serous chorioretinopathy

Background:  A prospective evaluation of the pattern of fundus autofluorescence in cases of acute versus chronic central serous chorioretinopathy (CSR).

Assessment of macular function by microperimetry in intermediate age-related macular degeneration

Purpose To evaluate retrospectively macular function by microperimetry (MP) in intermediate age-related macular degeneration (AMD). Methods Thirty eyes of 30 patients with intermediate AMD and a visual acuity of 20/32 or better were enrolled in the study. Macular function in patients with intermediate AMD and age-matched control group were carried out with MP1 microperimeter. Mean sensitivity (MS), mean defect (MD) parameters, fixation patterns, and localizations were evaluated. Mann-Whitney U test was used for the comparison of macular function parameters between the intermediate AMD group and the control group. Results MS was 12.7±2.8 dB and MD was detected as −6.2±2.2 dB in the intermediate AMD group by MP. Fixation patterns were stable in 22 eyes, relatively unstable in 7 eyes, and unstable in 1 eye. Fixation location was predominantly central in 19 eyes, poor central in 5 eyes, and predominantly eccentric in 6 eyes. In the control group MS was 18.0±0.6 dB and MD was −1.9±0.6 dB. When compared with control group, the decrease in MS and the increase in MD were statistically significant in the intermediate AMD group (p=0.001 and p=0.001, respectively). Conclusions Assessment of retinal sensitivity with MP1 microperimeter is a rapid, safe and noninvasive diagnostic method. Early macular function loss in intermediate AMD can be precisely detected by MP1 microperimeter before significant visual impairment is established and it is also useful for demonstrating the shift in the localization and the stability of fixation prior to progression of intermediate AMD to advanced and exudative stage.

Assessment and comparison of anterior chamber dimensions using various imaging techniques.

BACKGROUND AND OBJECTIVE To assess and compare the horizontal dimensions of the anterior chamber by different anterior segment imaging techniques. PATIENTS AND METHODS Eighty eyes of 40 patients without any ocular disease or previous ocular surgery were recruited and three consecutive measurements of internal anterior chamber diameter and white-to-white distance (WTW) parameters were determined. RESULTS Mean internal anterior chamber diameter was 11.80 +/- 0.39, 11.56 +/- 0.47, and 11.61 +/- 0.58 mm with Visante-OCT, SL-OCT, and Pentacam, respectively. Mean WTW distance was 11.87 +/- 0.35 and 11.65 +/- 0.32 mm by IOLMaster and OrbscanIIz, respectively. There was no significant difference between Visante-OCT and Pentacam, IOLMaster, and OrbscanIIz (P = .125, .918, and .314). However, detection of mean internal anterior chamber diameter was significantly greater by Visante-OCT than SL-OCT (P = .026). All devices displayed a high intrasession repeatability (repeated measured ANOVA, P > .05). CONCLUSION Internal anterior chamber diameter measurements using Visante-OCT, SL-OCT, and Pentacam, and WTW measurements using IOLMaster and OrbscanIIz were easy to handle and demonstrated good repeatability. Although similar results of horizontal anterior chamber diameter were determined by Visante-OCT, Pentacam, IOLMaster, and OrbscanIIz, the inter-device differences should be considered during clinical practice.

Correlation of retinal sensitivity and retinal thickness in central serous chorioretinopathy.

Aim: To evaluate the correlation of microperimetry (MP) and optical coherence tomography (OCT) in eyes having acute onset of central serous chorioretinopathy (CSCR). Methods: After a detailed ophthalmological examination, all cases were evaluated by fundus fluorescein angiography, OCT and MP. Mean macular thickness was detected by OCT. Mean macular sensitivity (MS) and mean defect (MD) were determined by MP. The correlation between OCT and MP findings was analyzed by Spearman’s correlation test. Results: Fifteen eyes with CSCR of 15 patients with a mean age of 40.5 ± 6.7 years were recruited. The mean visual acuity was 0.7 ± 0.2, and the mean macular thickness was 348.9 ± 75.8 μm. Mean MS and MD were 13.9 ± 4.6 and –5.2 ± 4.1 dB, respectively. The mean macular thickness was significantly correlated with both mean MS and MD (p = 0.011 and p = 0.017, respectively). A significant correlation was also found between mean macualt thickness, MS and MD in the central 1 mm, superior 3 mm and nasal 3 mm of the macula (p < 0.05). Conclusions: Our results demonstrated a significant correlation between structural and functional changes in CSCR. MP provides quantitative measurements of central macular function in CSCR that may supplement OCT findings as well as the better understanding of visual functions during the acute stage of the disease.

Fundus Autofluorescence in Optic Disc Drusen: Comparison of Confocal Scanning Laser Ophthalmoscope and Standard Fundus Camera

We have evaluated fundus autofluorescence (FAF) imaging in optic disc drusen (ODD). After a detailed ophthalmological examination, 28 eyes of 16 patients were evaluated by FAF imaging using a confocal scanning laser ophthalmoscope and a standard fundus camera. ODD displayed bright nodular autofluorescence. Increased FAF was observed using both the scanning laser ophthalmoscope and the fundus camera. However, high quality images with precise localization of hyaline material at the optic nerve head were only possible using FAF imaging with the confocal scanning laser ophthalmoscope. FAF images obtained using the fundus camera revealed only brightness at the optic nerve head without any detail except when maximum flash intensity was used. We conclude that FAF imaging may be used as a non-invasive, safe and rapid ancillary test for the confirmation of the diagnosis of drusen of the optic disc.