Internal Medicine

0521779407-18 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 8:1

1272 Red Cell Enzymes Refractive Disorders (Ametropias)

management

n/a

specific therapy

■No specific therapy is available.

■Avoidance of hemolysis-inducing drugs (and in some instances Fava

beans) in G6PD, GC and GSH synthase, and congenital glutathione

reductase deficiencies

■Splenectomy – not curative, but may ameliorate hemolysis in PK

and GPI deficiencies; may be necessary in infancy in transfusion-

dependent patients

follow-up

■Identify and counsel relatives at risk for defect.

■Prevent folate deficiency.

■Provide list of hemolysis-inducing agents to the patient to avoid

recurrence.

■In life-threatening cases, consider prenatal diagnosis after identify-

ing a specific mutation.

complications and prognosis

■Nonspecific complications of any chronic hemolytic state: jaundice,

leg ulcers, splenomegaly, gallstones, aplastic crises from Parvovirus

infection

REFRACTIVE DISORDERS (AMETROPIAS)

DAVID G. HWANG, MD, FACS

history & physical

■Emmetropia (normal vision)

➣Refractive disorders: images are not formed in precise focus on

the retina

➣Regular ametropias can be fully optically corrected using sphero-

cylindrical lenses. Includes hyperopia (farsightedness), myopia

(nearsightedness), regular astigmatism, and presbyopia (age-

related loss of accommodation).

➣Irregular ametropias cannot be fully corrected using lenses, most

commonly due to inhomogeneity in the corneal power (irregu-

lar corneal astigmatism), less commonly due to irregularities in