deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index cd544f1..eee646d 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
...
\section{Introduction}  There are many diseases that manifest in the posterior segment of the eye. These include age-related macular degeneration (AMD), retinal vein occlusion, and diabetic retinopathy and maculopathy. Together they account for the majority of blind registrations in the developed world.\cite{Bunce2010} Many of these diseases are treated with regular injections of drugs into the vitreous cavity, with the inconvenience of regular clinic review, cost of injection, discomfort, and small but repeated risks of complications.\cite{Edelhauser2010} Given the many downsides of regular intravitreal injections, the drug industry is actively investigating novel methods of delivering drugs to the posterior segment, including sustained release intravitreal devices,\cite{Callanan2008} transscleral drug delivery,\cite{Ambati2002, Ambati2000a, Ambati2000b} topical drug delivery (eye drops),\cite{ref7} drops),\cite{Tanito2011}  oral \cite{McLaughlin2013} and others such as iontophoresis.\cite{Molokhia2009} Topical drug delivery has many potential advantages, including self-administration, reduced cost, sustained drug levels, potentially fewer clinic visits, and the elimination of the risks associated with eye injections. Whilst desirable, topical drug delivery to the posterior segment is greatly impeded by the external ocular barriers to diffusion. This is compounded by the fact that many of the drugs used to treat posterior segment disease have a high molecular weight (MW), including ranibizumab (Lucentis, 48~kDa), aflibercept (Eylea, 97~kDa), and bevacizumab (Avastin, 150~kDa).