The lipid composition of drusen, Bruch's membrane, and sclera by hot stage polarizing light microscopy.
OBJECTIVE
To detect and identify, in situ, the lipid composition of drusen, diffuse Bruch's membrane deposits, and sclera in aging human eyes using hot-stage polarizing microscopy (HSPM), a method that allows qualitative determination of lipid subtypes within histologic sections based on morphology and melting temperatures of liquid crystals as monitored by birefringence during heating and cooling.


METHODS
Full-thickness buttons of the central macula and the periphery of human eyes from 17 patients were fixed in 5% calcium-buffered formalin. Frozen sections were stained with oil red O or Sudan black or were analyzed by HSPM.


RESULTS
Birefringent anisotropic droplets ("maltese crosses") with melting characteristics of cholesterol esters were identified within diffuse Bruch's membrane deposits, drusen, and sclera. Deposits that melted from crystal to oil without any maltese cross formation when cooled were present in the sclera and are consistent with triglyceride-rich deposits. Deposits with optical properties consistent with phospholipids were identified in a single aged eye. Eyes from young donors did not show these changes.


CONCLUSIONS
HSPM is a valuable technique for evaluating the nature of lipid deposits in aging eyes. Further studies are warranted to determine whether similar changes are also present in eyes with age-related macular degeneration.
Haimovici
R
R
. Department of Ophthalmology, Biophysics, and. Pathology, Boston University School of Medicine, Massachusetts, USA. robert.haimovici@bmc.org
Gantz
D L
DL
Rumelt
S
S
Freddo
T F
TF
Small
D M
DM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001391:Azo Compounds; D016570:Bruch Membrane / Q000378:metabolism* / Q000473:pathology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D050356:Lipid Metabolism; D008297:Male; D008859:Microscopy, Polarization; D008875:Middle Aged; D009281:Naphthalenes; D015593:Retinal Drusen / Q000378:metabolism* / Q000473:pathology; D012590:Sclera / Q000378:metabolism* / Q000473:pathology
D001391:Azo Compounds; D009281:Naphthalenes; C016118:Sudan Black B; C011049:oil red O