H. Nishihara

Differences in macular morphology between polypoidal choroidal vasculopathy and exudative age-related macular degeneration detected by optical coherence tomography.

Purpose: To evaluate the differences in the optical coherence tomographically determined macular morphology in eyes with polypoidal choroidal vasculopathy (PCV) from eyes with exudative age-related macular degeneration (AMD) quantitatively. Methods: The medical records of 208 eyes of 203 Japanese patients with PCV or exudative AMD who were newly treated for choroidal neovascularization were reviewed. The six linear, low-resolution, high-speed scans of 6 mm were analyzed using a manually assisted computer algorithm, which allowed us to manually draw spline lines arbitrarily on the images so that the subretinal fluid and neurosensory retina could be segmented. The thickness of the neurosensory retina and height of the serous retinal detachment (SRD) within the central 3-mm and 6-mm areas were calculated. Results: SRDs were observed in 53% (63/119) of the eyes with exudative AMD and in 78% (69/89) of the eyes with PCV (P < 0.001). The height of the SRD was 21.9 ± 3.7 &mgr;m (±SEMs) in eyes with exudative AMD and 56.3 ± 7.4 &mgr;m in eyes with PCV (P < 0.001). The thickness of the neurosensory retina was 300.0 ± 5.2 &mgr;m in eyes with exudative AMD and 275.8 ± 4.7 &mgr;m in eyes with PCV (P < 0.001). Conclusion: Eyes with PCV are characterized by a higher incidence of SRDs, greater SRD height, and less intraretinal edema than eyes with exudative AMD.

Effect of photodynamic therapy alone or combined with posterior subtenon triamcinolone acetonide or intravitreal bevacizumab on choroidal hypofluorescence by indocyanine green angiography.

Purpose: Choroidal hypofluorescence has been reported beneath the photodynamic therapy (PDT) site in clinical studies. We evaluated the choroidal hypofluorescence after combined PDT with posterior subtenon injection of triamcinolone acetonide or PDT with an intravitreal injection of bevacizumab for age-related macular degeneration. Methods: Two hundred and forty-two eyes with a subfoveal choroidal neovascularization caused by age-related macular degeneration were studied. Ninety-two eyes underwent PDT alone, 90 eyes underwent PDT with sub-Tenon injection of triamcinolone acetonide, and 60 eyes underwent PDT with intravitreal injection of bevacizumab. Verteporfin-induced choroidal hypoperfusion was determined by indocyanine green angiograms. The intensity of the diffuse fluorescence within the PDT site away from the choroidal neovascularization lesion and from the normal retina just peripheral to the optic disk was measured by densitometry (Topcon IMAGEnet computer system, Topcon, Tokyo, Japan) in the indocyanine green angiogram images obtained at 10 minutes 3 months after the PDT. The ratio of the average brightness of the retina within the PDT area to that of the retina peripheral to the optic disk (irradiated/nonirradiated retinal brightness ratio) was calculated for each angiogram. Results: The irradiated/nonirradiated retinal brightness ratio of the angiograms was 0.96 in the PDT-alone group, 0.85 in the sub-Tenon injection of triamcinolone acetonide-PDT group, and 0.89 in the intravitreal injection of bevacizumab-PDT group (Kruskal-Wallis H test, P < 0.05). Conclusion: The degree of choroidal hypofluorescence in the indocyanine green angiogram images 3 months after PDT in the sub-Tenon injection of triamcinolone acetonide and intravitreal injection of bevacizumab group was higher than that of PDT-alone group. Sub-Tenon injection of triamcinolone acetonide and intravitreal injection of bevacizumab can prolong the duration of the choroidal hypofluorescence after PDT.

Focal macular electroretinograms in eyes with wet-type age-related macular degeneration.

PURPOSE To study the properties of the focal macular electroretinograms (fmERGs) in eyes with untreated wet-type age-related macular degeneration (AMD). METHODS fmERGs were recorded from 157 eyes of 157 consecutive patients with untreated wet-type AMD (113 men, 44 women; age, 71.3 +/- 8.0 years). The fmERGs were recorded under direct fundus observation using a modified infrared fundus camera and a 15 degrees stimulus spot. Amplitudes and implicit times of the fmERGs recorded from the AMD patients were compared with those from 21 age-similar healthy controls. RESULTS The amplitudes of fmERGs in the AMD patients were significantly smaller (P < 0.001) and the implicit times were significantly longer (P < 0.001) than the corresponding values in the control eyes. There was a significant correlation between amplitude and implicit time of the fmERG and visual acuity (logMAR), but the degree of correlation was weak. The difference in the b/a amplitude ratio between the AMD patients and healthy controls was not significant. CONCLUSIONS The significant reduction in amplitude and the severe delay in implicit times of a- and b-waves of the fmERGs indicated significant functional alterations in the inner and the outer retinal layers of the macular area of eyes with wet-type AMD.

Focal macular electroretinograms after photodynamic therapy combined with posterior juxtascleral triamcinolone acetonide.

Purpose: Retinal function is commonly depressed transiently after photodynamic therapy (PDT). Additional treatment may prevent this impaired retinal function. The purpose of this study was to determine the changes in the focal macular electroretinograms (FMERGs) after PDT combined with TA for age-related macular degeneration. Methods: Thirty-four eyes that were successfully treated by PDT with a posterior juxtascleral injection of TA were studied. FMERGs, optical coherence tomography, and indocyanine green angiography were performed before and after the PDT. Results: The mean amplitudes of the FMERGs were not significantly decreased 1 week after PDT with TA (P > 0.05). The mean ratio of the FMERG b-wave 1 week after PDT to that before PDT was 1.09, with an indistinct hypofluorescence at the site of the PDT (18 eyes), and the ratio was 0.91 in the eyes with a distinct hypofluorescence border (16 eyes; P < 0.05). Conclusion: The combined use of TA with PDT mitigated the depression of retinal function soon after PDT. However, there were cases of severe choroidal hypoperfusion corresponding to the site of the laser spot that impaired retinal function in comparison to cases with mild hypoperfusion. Even with severe choroidal hypoperfusion, the deterioration in retinal function was relatively mild, with the b-wave FMERG reduced by only 10%.

New algorithm to analyze optical coherence tomographic images quantitatively

PurposeTo determine whether an algorithm we have developed can be used to measure the retinal thickness on optical coherence tomography (OCT) images.MethodsSix radial linear scans of 6 mm were made with the OCT instrument. The retinal thickness and volume determined with the built-in algorithm for the OCT instrument for 50 eyes of 50 control subjects with normal retinal boundaries were compared to the values obtained with our algorithm. The macular volume was also measured in 26 eyes of 25 subjects before and after photodynamic therapy (PDT).ResultsThe values obtained by the two algorithms in normal retinas were strongly correlated (R = 0.99). Bland-Altman plots of the mean differences between the two algorithm measurement values showed excellent agreement. The mean macular volume determined before and 1 week after PDT with the built-in algorithm was significantly larger than that measured with our algorithm (P = 0.035 pre-PDT; P = 0.004 1 week after PDT).ConclusionsOur algorithm can be used to obtain a valid measurement of retinal thickness in normal retinas. The macular volume before and 1 week after PDT obtained with the built-in algorithm was larger than those measurements obtained with our algorithm.