Bisretinoids: More than Meets the Eye

ELLIPSOID ZONE RECOVERY IN MACULAR TELANGIECTASIA TYPE 2

PURPOSE

To describe imaging features of macular telangiectasia type 2 eyes experiencing ellipsoid zone (EZ) recovery.

METHODS

Macular telangiectasia type 2 patients with EZ recovery were identified from the Natural History and Observational Registry study and underwent retinal imaging including optical coherence tomography and fundus photography. Eyes were graded according to the classification system by Gass and Blodi, the EZ-loss area was measured, and optical coherence tomography parameters were assessed by two independent readers. Parameters were analyzed for their presence before EZ recovery.

RESULTS

Twenty-four eyes of 21 patients (12 female, 57.12%; mean age 68 ± 8.54 years) were included in this study and followed for 21.25 months ± 12.79 months. At baseline, mean EZ-loss area was 0.036 mm 2 ± 0.028 mm 2 and 0.01 mm 2 ± 0.013 mm 2 at follow-up ( P < 0.001). A persisting external limiting membrane overlaying the EZ-loss was detected in 16 cases (66%), and hyperreflective changes in the outer retina were present in 18 cases (75%). Best-corrected visual acuity was 0.23 (20/32) ± 0.33 logMAR at baseline and 0.34 (20/40) ± 0.34 logMAR at follow-up ( P = 0.3).

CONCLUSION

Distinct optical coherence tomography features precede ellipsoid zone recovery in macular telangiectasia type 2 and warrant further studies investigating implications for patient care and clinical trial interpretation.

Lipofuscin, Its Origin, Properties, and Contribution to Retinal Fluorescence as a Potential Biomarker of Oxidative Damage to the Retina

Lipofuscin accumulates with age as intracellular fluorescent granules originating from incomplete lysosomal digestion of phagocytosed and autophagocytosed material. The purpose of this review is to provide an update on the current understanding of the role of oxidative stress and/or lysosomal dysfunction in lipofuscin accumulation and its consequences, particularly for retinal pigment epithelium (RPE). Next, the fluorescence of lipofuscin, spectral changes induced by oxidation, and its contribution to retinal fluorescence are discussed. This is followed by reviewing recent developments in fluorescence imaging of the retina and the current evidence on the prognostic value of retinal fluorescence for the progression of age-related macular degeneration (AMD), the major blinding disease affecting elderly people in developed countries. The evidence of lipofuscin oxidation in vivo and the evidence of increased oxidative damage in AMD retina ex vivo lead to the conclusion that imaging of spectral characteristics of lipofuscin fluorescence may serve as a useful biomarker of oxidative damage, which can be helpful in assessing the efficacy of potential antioxidant therapies in retinal degenerations associated with accumulation of lipofuscin and increased oxidative stress. Finally, amendments to currently used fluorescence imaging instruments are suggested to be more sensitive and specific for imaging spectral characteristics of lipofuscin fluorescence.