Steroid-induced posterior subcapsular cataracts (PSCs) exhibit three main distinctive characteristics: (i) association only with steroids possessing glucocorticoid activity, (ii) involvement of aberrant migrating lens epithelial cells, and (iii) a central posterior location. The first characteristic suggests a key role for glucocorticoid receptor activation and subsequent changes to the transcription of specific genes. Glucocorticoid receptor activation is associated in many cell types with proliferation, suppressed differentiation, a reduced susceptibility to apoptosis, altered transmembrane transport, and enhancement of reactive oxygen species activity. Glucocorticoids may be capable of inducing changes to the transcription of genes in lens epithelial cells that are related to many of these cellular processes. This review examines the various mechanisms that have been proposed to account for the development of PSC in the context of recent DNA array studies. Additionally, given that the glucocorticoid receptor can also engender wide-ranging indirect activities, glucocorticoids could also indirectly affect the lens through the responses of other cells within the ocular compartment and/or through effects on cells at more remote locations. These indirect mechanisms, which, for example, could be mediated through alterations to the intraocular levels of growth factors that normally orchestrate lens development and maintain lens homeostasis, are also discussed. Although the mechanism of steroid cataract induction remains unknown, glucocorticoid-induced gene transcription events in lens epithelial cells, and also other intraocular or systemic cells, likely interact to generate steroid cataracts. Finally, although evidence for glucocorticoid-protein adduct formation in the lens is inconclusive, the generation of such adducts cannot yet be discounted as a contributing factor and must necessarily be retained in discussions of the etiology of steroid cataract.
Cataracts are relatively simple to diagnose by an ophthalmologist or an optometrist during a routine eye examination. It is important, when making the diagnosis of cataract, to also examine the entire eye for evidence of any other eye disease which may be compromising the vision. In addition to taking a medical and ocular history and visual acuity test, the ophthalmologist will check eye movements and pupillary responses, measure the pressure inside the eyes and examine the both front and back of the eyes after the pupils have been dilated with drops.
It is important to remember to follow all of your preoperative instructions, which will usually include not eating or drinking anything after midnight the day prior to your surgery. As cataract surgery is an outpatient procedure, arrangements should be made with family or friends to transport you home after the surgery is complete. Most cataract surgery occurs in either an ambulatory surgery center or a hospital. You will be required to report several hours before the scheduled time for your surgery. You will meet with the anesthesiologist who will work with the ophthalmologist to determine the type of sedation that will be necessary. Most cataract surgery is done with only minimal sedation without having to put you to sleep . Numbing drops or an injection around the eye will be used to decrease sensation of the eye.