Not too long ago, the number one corneal surgical procedure, if contact lenses would not suffice, was a penetrating keratoplasty - typically referred to as PK or PKP. Life was simpler then! Now there are so many procedures that it is hard to even remember their names. Joseph Sowka, Andrew Gurwood and Alan Kabat in Review of Optometry's The Handbook of Ocular Disease Management do a fine job describing and explaining the different procedures (page 30a of the handbook). There is DLK (deep lamellar keratoplasty), more often referred to as LK, in which the cornea is partly stripped as an alternative to PK. Examples of this are DALK (deep anterior lamellar keratoplasty), which replaces the cornea up to the level of Descemet's membrane, and PLK (posterior lamellar keratoplasty). In the latter case, the most posterior elements of the cornea are replaced in order to overcome a dysfunctional endothelial layer. DLEK (deep lamellar endothelial keratoplasty) was the name given to PLK when it was adopted in the USA, and this gave way to DSEK and DMEK, which involve the removal of far less corneal tissue from the recipient. DSEK (Descemet's stripping endothelial keratoplasty, also referred to as DSAEK or descemet's stripping automated endothelial keratoplasty) peels away Descemet's membrane and the endothelium at the level of the posterior stroma. DMEK (Descemet's membrane endothelial keratoplasty, sometimes referred to as DMAEK or Descemet's membrane automated endothelial keratoplasty) represents the most recent and least invasive approach, replacing only the endothelium and Descemet's membrane. DMEK represents pure anatomic replacement surgery for endothelial disease, and no stroma is transplanted as in DSEK. And I thought remembering all 26 letters of the alphabet as a young kid was complicated! The ABC-song helped. Maybe we need a song, too, for the corneal procedures!

The October issue of Contact Lens Spectrum features the annual (R)GP lens special. Ed Bennett delivers the annual report 2012 which discusses where this market is going (and growing). Other interesting topics include 'Tips for Applying Scleral Lenses' by Greg DeNaeyer, 'Scleral GP's: More Indications?' by Neil Pence, 'GP Contact Lens Care Pearls' by Michael Ward, and a number of articles on myopia control and on the management of astigmatism with (R)GPs. For all articles: see link below.   

Contact Lens Spectrum - October 2012 

Inna Baran et al from the Boston Foundation for Sight, one of the world's most renowned places for scleral lens fitting, published a paper 'PROSE treatment for corneal ectasia.' PROSE stands for 'Prosthetic replacement of the ocular surface ecosystem,' and makes use of custom-made scleral lens prosthetic devices. This retrospective study on 118 eyes was undertaken to evaluate the success of PROSE treatment of corneal ectasia at six months. Prior contact lens wear was reported in 90% of patients, but only 28% were wearing contact lenses at the time of first consultation, suggesting that the degree of ectasia presented made it a challenge to fit corneal lenses, according to the authors. All candidate eyes with corneal ectasia (100%) could be fitted with the device. After 6 months, 88% of eyes still wore the PROSE device. A significant improvement in mean visual acuity was shown, with 93% of eyes achieving visual acuity of 20/40 or better, and a significant improvement in visual functioning by a mean of 27.6 points was demonstrated by using the NEI VFQ-25 questionnaire.

Contact Lens & Anterior Eye - October 2012