Many systemic lysosomal storage disorders show basic
corneal opacities already in childhood. The lysosome is a cell organelle, produced by Golgi's apparatus, that is surrounded by a membrane and contains hydrolytic
enzymes that break down food molecules, especially
proteins and other complex molecules. The ophthalmologist's precise diagnosis of corneal clouding at the
slit-lamp may reveal the correct interpretation of the specific lysosomal storage disorder. It is very important to diagnose such diseases as soon as possible because today the development of systemic enzymatic
therapies has broadened the therapeutic armamentarium for the current standard of care. The following corneal landmarks of systemic storage diseases and of the modern systemic
therapy are presented: cornea verticillata in
Fabry's disease, periodic infusion of
alpha-galactosidase a; Kayser-Fleischer's ring in
Wilson's disease,
zinc, trienetin, low
copper diet; multiple, punctiform crystals in
cystinosis,
cysteamine, Raptor RP 103(DR
cysteamine) that reduces the cytotoxity in form of continous dissolving of
cystine from lysosome,
renal transplantation, haematopoietic
stem cell transplantation; peripheral ring, but not true
lipid arc, and moderate stromal haze in
LCAT-deficiency, injection of recombinant
enzyme or of encapsulated LCAT-secreting cells; diffuse stromal haze in
mucopolysaccharidoses (MPS).
Enzyme replacement therapy is currently indicated for MPS I, MPS II, and MPS VI, haematopoietic
stem cell transplantation; painful, bilateral pseudo-dendritic opacities in
tyrosinemia type II (eponym:
Richner-Hanhart syndrome), low
phenylalanine and
tyrosine diet result in complete disappearance of corneal alterations with a consecutive painfree period. Strict diet during the whole life is necessary to prevent corneal recurrences and the occurrence of palmo-plantar
keratoses. Such
therapies can enable the patient to lead an otherwise normal life for decades.