Within our field, the popularity of scleral lenses is significant - it seems to even exceed the expectations of many experts. Luckily, we know so much more about scleral lenses today than we did a few years back - although some crucial issues still remain unanswered. But the number of relevant publications since 2010 exceeds that of before 2010, both from peer-reviewed publications and from clinical articles. Therefore, it seemed time to update the Scleral Lens Guide, the first edition of which was composed in 2010 and launched at the Global Specialty Lens Symposium in January 2011. The new 2.0 version was just launched at the recent, very successful EFCLIN meeting in Venice (Italy). As an illustration of the growing-up process in the updated version, in terms of the volume of publications on the topics, the reference list expanded from 2.5 to 5 pages, and multiple pages of text have been added. Topics such as 'oxygen delivery to the cornea,' 'scleral lens fogging' and 'scleral shape and asymmetric scleral lenses' all received additional attention in this new guide, just to name a few. It also incorporates the Michigan College of Optometry scleral lens fit grading scales. But honestly, almost literally, not a single sentence came out untouched, so in the end the guide got a complete makeover. I think it is fair to state that we are now at scleral lenses 2.0 with the new knowledge we have. And several companies have developed or are developing new instruments to measure scleral shape. This will further advance our understanding of scleral lens shape, and hopefully it will further improve the quality of the scleral lens fit. Stay tuned: I-site will work to keep you informed.

Anterior ocular surface shape (including the scleral shape) increasingly plays an important role in optimizing scleral lens fitting. The May issue of Contact Lens Spectrum hosts an intriguing article by Lee Hall on the topic. He states that 'understanding the shape of the anterior ocular surface is essential to successful scleral contact lens fitting'. The mean measured ocular sagittal height over 15mm in the horizontal plane is 3,700 microns, with a variation of ± 170 microns and a range of between 3,230 and 4,080 microns - which is in line with other studies. He presents data from a Pacific University study in which they evaluated the scleral profiles of 40 normal healthy subjects (80 eyes) using the Eye Surface Profiler (Eaglet Eye). Measurements were taken in the primary and oblique positions of gaze at chords of 13.0mm, 15.0mm and 17.0mm. The results showed marked asymmetry 360º around the scleral faces, but also marked differences in sagittal depth between opposing faces in the horizontal and vertical meridians, with the nasal and superior faces exhibiting the least scleral sagittal depth. The disparity increased significantly with the increase in chord diameter, especially along the horizontal meridian. Image: Eye Surface Profiler (Eaglet Eye)