Macular telangiectasia--changes in macular pigment optical density during a 5-year follow-up.

Purpose: To quantitatively analyze the distribution of macular pigment (MP) over a period of 5 years and for monitoring progression of macular telangiectasia.
Methods: Macular pigment concentration (autofluorescence, excitation wavelengths: 488 and 514 nm) was determined at baseline and after 5 years in 43 eyes of 22 subjects (46-80 years; mean, 65.6 years; 10 men) participating in the macular telangiectasia project.
Results: Mean MP density at 0.5° declined in the segment (one eighth of a circle) with the highest MP optical density (-0.04 density units; P= 0.015), where density units (DU), and also averaged in the 2 segments that divided segments with detectable MP from those in which MP was no longer detectable (-0.04 density units; P = 0.0005). In the first segment mentioned, 2° values decreased to a lesser extent and not significantly. The diameter of MP loss expanded horizontally from 2.64 mm to 2.74 mm (P = 0.0001) but not vertically. Macular pigment density in the "halo" of peripheral MP at a mean of 5.44° (4.53-6.21°) increased (+0.01 DU; P= 0.01).
Conclusion: Five years of follow-up resulted in central (0.5°) reduction and peripheral (4.53-6.21°) accumulation of MP. Longer period of follow-up may disclose significant changes in paracentral locations. The area of central MP loss expands in particular in a horizontal direction and less vertically. Centrifugal movement of MP during disease may explain our findings.