How Far We Have Come in Preserving Vision and Sight
BY LEO SEMES, OD, FAAO
At a recent roundtable discussion, participants were asked what they thought was the most significant ophthalmic advancement of the past decades. Among the candidates were optical coherence tomography (OCT), prostaglandin analogs to lower intraocular pressure (IOP), and anti-VEGF agents. While each is significant in its own right, any one of those could be considered the most significant.
Optical Coherence Tomography
OCT has given us new insights into macular and other retinal disorders. The differentiation within retinal layers offers views of retinal physiology previously only possible with histological sectioning. Monitoring retinal remodeling following treatment has now become possible at the near-micron level. Diagnostic capabilities offered by OCT have largely replaced the tedium and burden of fluorescein angiography. New perspectives on the vitreomacular interface have been characterized using OCT as well. From the internal limiting membrane (ILM) to the retinal pigment epithelium (RPE) and everywhere in between, the retina has become better understood.
There is a new frontier ahead for OCT. Besides the volumetric data collection and screening strategies, directional OCT now allows new perspectives on Henle’s fiber layer (Lujan et al, 2011). In addition, advances in adaptive optics will offer even further insights into retinal and choroidal function and dysfunction (Zawadski et al, 2014).
Diagnostically, early detection of conditions such as clinically significant macular edema among diabetic patients, macular edema secondary to retinal vein obstructions, or fluid in early neovascular age-related macular degeneration (AMD) can now lead to earlier vision-preserving treatments.
Clearly, the introduction of prostaglandin analogs to lower IOP in those diagnosed with ocular hypertension or glaucoma represented a revolution in the care of glaucoma patients. The first revolution was the introduction of topical beta-blockers to replace the then-contemporary treatment strategy represented by cholinergics (and their ilk). This has been suggested as one of the major reasons that blindness from glaucoma has decreased over the past two decades (Malihi et al, 2014).
While the diagnostic information from OCT is valuable in decision-making and treatment direction and prostaglandin analogs have had a positive impact on visual disability from glaucoma, the introduction of anti-VEGF agents is also significant for patients who have “wet” AMD (Figure 1). And, while this form of AMD is the minority for AMD cases, for the first time, an intervention for wet AMD has demonstrated improvement and not just stabilization of visual performance. This is a valuable addition to the treatment armamentarium of preserving vision. CLS
Figure 1. OCT high-resolution images of AMD treated with intravitreal anti-VEGF agents over six years with stable anatomy. There is resulting geographic atrophy, and VA is 20/80.
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Dr. Semes is a professor of optometry at the UAB School of Optometry. He is a consultant or advisor to Alcon, Allergan, B+L, Sucampo, and Zeiss and is a stock shareholder in HPO and Arctic DX.