Evaluation of the Correlation Between Tear Meniscus Parameters and Conventional Dry Eye Tests

Purpose: To evaluate the correlation between clinical tests, patient symptoms and spectral optical coherence tomography (OCT; RTVue, Optovue)-derived lower tear meniscus (TM) parameters and to verify sensitivity and specificity of TM parameters in the diagnosis of dry eye disease. Material and Method: 38 eyes of 38 patients (22 dry eye patients, 16 healthy subjects) were examined in this prospective study. After routine ophthalmologic examination, anterior segment OCT-derived TM height (TMH), TM depth (TMD), and TM area (TMA) were measured, and tear break-up time (TBUT) and Schirmer test with anesthesia were assessed in all patients. For evaluation of symptoms, the participants completed ocular surface disease index (OSDI) questionnaire. Correlation between tests was assessed using Pearson’s correlation coefficient (r). Results: There was a significant positive correlation between Schirmer test results and TMH, TMA and TMD (r=0.79, 0.58, 0.58, respectively). TBUT was positively correlated with TMH, however, it was not correlated with TMA and TMD (r=0.63, 0.14 and 0.10, respectively). There was no significant correlation between OSDI score and 3 parameters of TM. TM measurements were significantly lower in dry eyes than in controls. Sensitivity and specificity for dry eye diagnosis were 81.5% and 86.8% for TMH, 78.9% and 76.3% for TMA, and 76.3%, and 52.6% for TMD, respectively. Discussion: OCT-derived TM parameters were correlated with Schirmer test, but there was no correlation between TM parameters and patient symptoms. TM measurements have high sensitivity and specificity for the diagnosis of dry eye. (Turk J Ophthalmol 2013; 43: 446-50

The Effect of Artificial Tears on Corneal Higher Order Aberrations in Dry Eye Patients

Purpose: To assess the effects of artificial tears on corneal higher order aberrations in dry eye patients. Materials and Methods: 30 right eyes of 30 newly diagnosed dry eye patients were evaluated in this prospective study. After routine ophthalmological examination, Schirmer test and tear break-up time (TBUT) test were performed in all patients. Anterior corneal aberrations were derived from conversion of the corneal elevation profile into corneal wavefront data with 6.0 mm pupil diameter using Zernike polynomails by corneal topography before and 5 minutes after instillation of artificial tear (Eyestil®). Corneal optical aberrations were compared before and after instillation of eyedrop. Results: The study included 17 women and 13 men; the average age of the patients was 44.36±13.22 years. Mean TBUT was 4.78±2.78 seconds and mean Schirmer value was 3.58±2.45 mm/5 minutes. After instillation of artificial tear, significant reductions in corneal total aberration from 1.120±0.35 µm to 0.960±0.34 µm, higher order aberration from 0.674±0.26 µm to 0.464±0.18 µm, coma-like aberration from 0.283±0.10 µm to 0.238±0.09 µm, and spherical-like aberration from 0.254±0.11 µm to 0.221±0.08 µm were detected (all, p<0.001). After eyedrop instillation, statistically significant increment was observed in Strehl ratio (p<0.001). Conclusion: As well as reducing the dry eye symptoms, artificial tears also cause increment in optical quality of the eye. Benefits of artificial tears on visual quality can be evaluated objectively via corneal wavefront aberrations. (Turk J Ophthalmol 2014; 44: 119-22

Optical Coherence Tomography Pachymetry Mapping in Diagnosis of Keratoconus

Purpose: To evaluate abnormal corneal thinning using optical coherence tomography (OCT) pachymetry mapping in keratoconus patients. Material and Method: In this prospective study, 57 eyes of 33 keratoconus patients and 50 eyes of 25 control subjects without ocular pathology were compared. After routine ophthalmologic examination, corneal topography and corneal pachymetry mapping by OCT with anterior segment module were performed in all subjects. Central corneal thickness (CCT), minimum corneal thickness (Min), superior-inferior (S-I), minimum-median (Min-Med), superonasal-inferotemporal (SN-IT), superotemporal-inferonasal (ST-IN), minimum-maximum (MinMax) and minimum corneal vertical localization(MCVL) parameters were evaluated from the OCT pachymetric maps. Measurements were performed three times in all patients, and the means of these data were used for statistical analysis and comparisons. Cut-off values were determined for all OCT-derived parameters. Sensitivity, specificity, and area under the receiver operating characteristic (AROC) curve were also calculated for these parameters. Results: Keratoconic corneas were thinner. Minimum corneal thickness was 425±63 µm in the keratoconus group, and 513.7±3 µm in the control group (p<0.001). The thinnest corneal location was inferiorly displaced in the keratoconus group. MCVL value was -845.6±427.9 µm in the keratoconus group and -419.6±240.1 µm in the control group (p<0.001). Min-med was -46.3±23.8 µm and 18.4±16.3 µm in keratoconus and control groups, respectively. Corneal thinning was more asymmetric in the keratoconus group ( S-I, SN-IT, ST-IN parameters were statistically different between the groups, p<0.001). Sensitivity, specificity, and AROC values of the OCT pachymetric parameters were within the range of 82-92%, 54-89%, and 0.674-0.922, respectively. Discussion: OCT pachymetry maps have high sensitivity and specificity for keratoconus diagnosis. OCT provides additional information in patients whose corneal topography was inconsistent with clinical signs and interpretation of both devices together would be more valuable in the diagnosis of keratoconus. (Turk J Ophthalmol 2013; 43: 236-4

Türk halkında Ganglion hücre kompleksinin ve retina sinir lifi kalınlığının değerlendirilmesi

*Adam, Mehmet ( Aksaray, Yazar )To determine the effects of age and sex on retinal ganglion cell complex thickness and retinal nerve fiber layer thickness in the eyes of healthy individuals. Patients and Methods: We evaluated 393 healthy subjects aged 10-84 years in a cross-sectional study between November 2012 and May 2013. Linear regression analysis and Pearson’s correlation were performed to analyze the difference in the age-related changes. We evaluated the relationship between the retinal nerve fiber layer thickness and ganglion cell compl ex thickness using Pearson’ s correlation. Results: The whole population mean retinal nerve fiber layer thickness was 108.94±9.77 μm, and decreased by 0.101 μm/year. The most significant decrease was in the supero-temporal sector. There was no difference in the retinal nerve fiber layer thickness between sexes, except for the superior quadrant. The mean ganglion cell complex thickness was 97.45±6.42 μm, and decreased by 0.043 μm/year. There was no relationship between sex and ganglion cell complex thickness. The mean retinal nerve fiber layer and ganglion cell complex thicknesses exhibited a significant c orrelation. Conclusion: The ganglion cell complex thickness and retinal nerve fiber layer thickness decreased significantly with age but ganglion cell complex thickness was less af fected.Sağlıklı bireylerde yaş ve cinsiyetin ganglion hücre kompleksi ve retina sinir lifi kalınlığı üzerine etkisinin değerlendirilmesi amaçlandı. Hastalar ve Yöntem: Bu kesitsel çalışmada Kasım 2012 - Mayıs 2013 tarihleri arasında yaşları 10-84 arasında değişen 393 sağlıklı katılımcıyı değerlendirdik. Yaşa bağlı değişikler lineer regresyon analizi ve Pearson korelasyon analizi ile incelendi. Retina sinir lifi kalınlığı ve ganglion hücre kompleksi arasındaki ilişki pearson korelasyon testi ile değerlendirildi. Bulgular: Tüm populasyonun ortalama retina sinir lifi kalınlığı 108.94±9.77 μm idi ve yıllık 0.101 μm azalmaktaydı. En önemli azalma üst temporal bölümde görüldü. Üst kadran hariç retina sinir lifi kalınlığında cinsiyete göre fark bulunamadı. Ortalama ganglion hücre kompleksi kalınlığı 97.45±6.42 μm olarak bulundu ve her yıl 0.043 μm azalmaktaydı. Cinsiyetle ganglion hücre kalınlığı arasında bir ilişki bulunmazken retina sinir lifi ile ganglion hücre kompleksi aras ında anlamlı korelasyon tespit edilmiştir . Sonuç: Retina sinir lifi kalınlığı ve ganglion hücre kompleksi kalınlığı yaşla birlikte önemli ölçüde azalmaktadır ancak ganglion hücre kalınlığı daha az etkilenmektedir