S. P. Rothenbuehler

Macular Thickness Measurements in Healthy Eyes Using Six Different Optical Coherence Tomography Instruments

PURPOSE To compare central retinal thickness (CRT) measurements in healthy eyes by different commercially available OCT instruments and to compare the intersession reproducibility of such measurements. METHODS Six different OCT instruments (Stratus OCT [Carl Zeiss Meditec, Inc. Dublin, CA], SOCT Copernicus [Reichert/Optopol Technology, Inc., Depew, NY], Spectral OCT/SLO [Opko/OTI, Inc., Miami, FL], RTVue-100 [Optovue Corp., Fremont, CA], Spectralis HRA+OCT [Heidelberg Engineering, Inc., Heidelberg, Germany], and Cirrus HD-OCT [Carl Zeiss Meditec, Inc.]) were used to assess CRT in both eyes of healthy subjects. Measurements were performed in two different sessions on the same day with each of the systems. From these measurements, the mean CRT was calculated. For the assessment of the intersession reproducibility of the instruments, we calculated the coefficient of the variation of test-retest variation. RESULTS Twenty healthy subjects were included in the study. Compared with the Stratus OCT all spectral OCT instruments showed significantly higher CRTs. The Spectralis HRA+OCT and Cirrus HD-OCT showed similar CRT values but significantly higher values than did all other instruments. The coefficients of variation for repeated measurements was 3.33% for the Stratus OCT, 0.46% for the Spectralis HRA+OCT, 3.09% for the Cirrus HD-OCT, 2.23% for the OCT/SLO, 2.77% for the RTVue-100 OCT, and for the SOCT 3.5%, respectively. discussion. The six OCT systems provided different results for CRT. The measurements with the Stratus OCT showed the lowest thicknesses, whereas those with the Cirrus HD-OCT and Spectralis HRA+OCT yielded the highest ones. These discrepancies can be explained by the differences in the retinal segmentation algorithms used by the various OCT systems. Whereas the Spectralis HRA+OCT and Cirrus HD-OCT include the RPE layer in the retinal segmentation, the other instruments do not. The data imply that the different OCT systems cannot be used interchangeably for the measurement of macular thickness.

Effects of ranibizumab in patients with subfoveal choroidal neovascularization attributable to age-related macular degeneration.

PURPOSE To demonstrate not only prevention of vision loss but also improvement in best-corrected visual acuity (BCVA) after treatment with ranibizumab on a variable-dosing regimen over 24 months in patients with age-related macular degeneration (AMD). DESIGN Interventional case series. METHODS SETTING Institutional. STUDY POPULATION One hundred and thirty-eight eyes of 138 patients treated intravitreally with 0.5 mg ranibizumab (Lucentis; Novartis, Basel, Switzerland). Age above 50 years, BCVA 0.2 to 1.2 logarithm of the minimal angle of resolution (logMAR), primary or recurrent subfoveal choroidal neovascularization (CNV) secondary to AMD. OBSERVATION PROCEDURES After single initial treatment, monthly follow-up examination. Retreatment in case of one of the following: sign of subretinal fluid or intraretinal edema, increase in central retinal thickness (CRT) on optical coherence tomography (OCT), active CNV on fluorescein angiography, increase of metamorphopsia, and loss of BCVA > 5 letters on Early Treatment Diabetic Retinopathy Study (ETDRS) chart. MAIN OUTCOME MEASURES Compared with baseline: proportion of eyes gaining > or = 15 letters, proportion of eyes losing or gaining < 15 letters, change in CRT. RESULTS After 24 months, 30% of eyes gained > or = 15 letters. After 24 months, 55% of eyes lost or gained < 15 letters. Mean CRT of 386 +/- 145 microm at baseline was significantly reduced to 211 +/- 39 microm after 24 months (P = .036). Mean injection number per patient was 5.6 +/- 2.9 and 4.3 +/- 3.8 from baseline to month 12 and month 12 to 24, respectively. CONCLUSION Intravitreal ranibizumab on a variable-dosing regimen was effective in significantly increasing mean BVCA and reducing CRT. This beneficial outcome was achieved with a low-rate of mild ocular adverse effects among our patients.

Predictors of Short-Term Visual Outcome after Anti-VEGF Therapy of Macular Edema due to Central Retinal Vein Occlusion

PURPOSE The purpose of this study was to analyze predictive factors for best-corrected visual acuity (BCVA) after anti-VEGF treatment in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO). METHODS This prospective study enrolled treatment-naive patients with ME secondary to CRVO. BCVA, ophthalmoscopy, fundus photography, and spectral domain optical coherence tomography (SD-OCT) imaging were performed. SD-OCT was analyzed for integrity of the external limiting membrane (ELM), photoreceptor inner segments (IS), and outer segments (OS). Patients were treated with intravitreal bevacizumab (1.25 mg) or ranibizumab (0.5 mg). BCVA outcome was analyzed 4 weeks after the first injection. RESULTS Sixty-two eyes of 62 patients (39 men, 23 women; mean age: 67 ±16 years) were included. In 55%, the ELM was intact. These eyes also showed intact photoreceptor IS/OS in horizontal and vertical single scans. Disturbed ELM was seen in 45% and was accompanied by focal disintegration of IS/OS. Four weeks after injection, 58% showed clinically relevant increases of BCVA (≥5 letters). Mean BCVA ranged from 20 to 86 letters. The mean BCVA increase was 18 ± 12 letters in eyes with intact ELM compared with 4 ± 10 letters with disturbed ELM (P < 0.001). CONCLUSIONS Depending on the integrity of the outer retinal layers, the authors observed rapid and clinically relevant improvement in BCVA after the first anti-VEGF injection. In the development of an optimal treatment regime, the indication for treatment and re-treatment should be based on functional and morphologic findings, such as the deterioration of outer retinal layers. Intact ELM in SD-OCT imaging is associated with better visual outcomes after intravitreal anti-VEGF treatment in patients with ME secondary to CRVO.