Relating Retinal Morphology and Function in Aging and Early to Intermediate Age-related Macular Degeneration Subjects

PURPOSE

To evaluate relationships between age-related macular degeneration (AMD) morphology on spectral-domain optical coherence tomography (SDOCT) and visual function.

DESIGN

Cross-sectional, observational.

METHODS

From the Alabama Study on Early AMD baseline visit, visual acuity, cone-mediated sensitivity, rod-mediated dark adaptation, and SDOCT were obtained in 1 eye per subject with no apparent retinal aging (n = 15), normal aging (n = 15), early AMD (n = 15), and intermediate AMD (n = 46). The volumes of retinal pigment epithelium (RPE)-drusen complex, RPE-drusen complex abnormal thinning, RPE-drusen complex abnormal thickening, and inner and outer retina were calculated in specified regions using semi-automated SDOCT segmentation.

RESULTS

Better cone-mediated sensitivity was associated with greater RPE-drusen complex volume (r = 0.34, P < .001) and less RPE-drusen complex abnormal thinning volume (r = -0.31, P = .003). Longer rod-mediated dark adaptation time, the duration for rod-mediated sensitivity to recover from photo-bleach exposure, correlated with lower RPE-drusen complex volume (r = -0.34, P = .005) and greater RPE-drusen complex abnormal thinning volume (r = 0.280, P = .023). In 19 eyes with subretinal drusenoid deposits (SDD) vs 47 eyes without SDD, rod-mediated dark adaptation time was longer (mean ± SD 13.5 ± 7.0 vs 10.2 ± 3.1 minutes, P = .004), RPE-drusen complex abnormal thinning volume was greater (P < .0001), and visual acuity and cone sensitivity did not differ.

CONCLUSION

Decreased function relates to structural markers on SDOCT in AMD. Because the RPE-drusen complex includes the interdigitation of outer segments and RPE apical processes and SDD in eyes with AMD, slower dark adaptation might be related to structural abnormalities of the RPE, the RPE-photoreceptor interface, or both.

Optical Coherence Tomography Angiography of Type 1 Neovascularization in Age-Related Macular Degeneration

Age-related macular degeneration continues to be the leading cause of severe central vision loss in older adults of European descent. Optical coherence tomography angiography (OCT-A) enables more accurate identification of type 1 neovascularization in age-related macular degeneration than traditional fluorescein and indocyanine green angiographies. In addition, OCT-A facilitates the morphological classification of type 1 lesions, including features characteristic of early, mature, and fibrotic lesions. Vessel complex analysis, including lesion area and capillary density quantification, can also be readily measured and monitored over time. Performing this analysis following anti-vascular endothelial growth factor therapy may lead to a better understanding of the efficacies and responses to such treatments. Although some limitations currently exist, OCT-A is a promising imaging modality that could prove to have profound implications if incorporated into regular clinical practice.

Macular ganglion cell complex and retinal nerve fiber layer comparison in different stages of age-related macular degeneration

PURPOSE

To employ optical coherence tomography (OCT) to analyze the morphologic changes in the inner retina in different categories of age-related macular degeneration (AMD).

DESIGN

Observational cross-sectional study.

METHODS

Single-center study. Inclusion criteria were age over 50, diagnosis of Age-Related Eye Disease Study (AREDS) category 2 and 3, naïve neovascular AMD, and atrophic AMD. Healthy patients of similar age acted as a control group. Primary outcome measures were the changes in ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). Secondary outcomes included modifications of rim area and cup-to-disc ratio.

RESULTS

One hundred and thirty eyes of 130 patients were recruited: 26 eyes for AREDS category 2, 26 for AREDS category 3, 26 for neovascular AMD, 26 with atrophic AMD, and 26 controls. Mean peripapillary RNFL thickness was significantly lower in neovascular AMD, compared to controls (P = .004); peripapillary RNFL did not significantly vary among AREDS category 2 and 3 and atrophic AMD groups, compared to controls. Mean GCC thickness was higher in the control group, becoming progressively thinner up to neovascular and atrophic AMD groups (P < .0001). Rim area was significantly thinner in the neovascular AMD group compared with controls (P = .047); cup-to-disc ratio was higher in the neovascular AMD group compared with the control group (P = .047).

CONCLUSIONS

This study demonstrates that eyes with neovascular AMD display reduced RNFL and GCC thickness. RNFL is partially spared in atrophic advanced AMD. The identification of alteration in RNFL and GCC thickness may reveal useful for future therapeutic implications.

The incidence of neovascular subtypes in newly diagnosed neovascular age-related macular degeneration

PURPOSE

To determine the frequency of neovascularization subtypes as determined by fluorescein angiography (FA) alone vs FA and optical coherence tomography (OCT) grading in age-related macular degeneration (AMD).

DESIGN

Retrospective cohort.

METHODS

participants: Newly diagnosed neovascular AMD patients who initiated intravitreal anti-vascular endothelial growth factor therapy by 1 physician from October 1, 2005 to December 1, 2012. interventions: Two independent graders classified the baseline lesions using FA alone and FA+OCT. main outcome measures: Analysis of the frequency of lesion subtypes by FA alone or FA+OCT and agreement between both classification systems was performed.

RESULTS

A total of 232 patients (266 eyes) fit the inclusion criteria. Mean age was 86.3 years; 67.7% of eyes (180/266) were from female patients, and 95.5% (254/266) were from white patients. The distribution using FA alone was 49.6% (132/266), 12.0% (32/266), 28.6% (76/266), and 9.8% (26/266) among occult, classic, retinal angiomatous proliferation, and mixed choroidal neovascularization, respectively. With FA+OCT, 39.9% (106/266), 9.0% (24/266), 34.2% (91/266), and 16.9% (45/266) were type 1 (sub-retinal pigment epithelium), type 2 (subretinal), type 3 (intraretinal), and mixed neovascularization (NV), respectively. The κ statistic was 0.65 (standard error ±0.37, P < .001) between the 2 classification systems, representing good agreement.

CONCLUSION

With both FA-alone and FA+OCT grading, we found a higher incidence of type 3 NV in eyes with newly diagnosed neovascular AMD than that reported in prior studies. The κ statistic between the 2 classification systems showed "good" agreement. The discrepancies are likely attributable to the identification of a higher frequency of type 3 and mixed NV and a lower frequency of type 1 NV with the aid of OCT.