Old Versus Zaman Innovative Techniques Of Bowman Layer Transplantation Type I And Ii.

To assess the outcome of BLT in advanced keratoconus in patients not suitable for ultra violet cross-linking or intra stromal corneal ring segments, complications and results of old versus zaman innovative techniques of BLT type I and II.

Quasi experimental study. BLT performed in Dept of Ophthalmology Khyber Teaching Hospital Peshawar from Sept 2018 to Oct 2018 (18 months follow up).

In old technique of BLT, mid corneal stromal dissection followed by implantation of manually isolated bowman layer from a donor into the recipient stromal pocket was performed in ophthalmology department, Khyber Teaching Hospital Peshawar. In Zaman Technique of BLT type I, manually harvested BL was placed after debridement of surface epithelium close to natural anatomical location. In Zaman Technique of BLT type II, manually harvested BL was placed in 150um depth recipient cornea pocket created with femtosecond laser.

In old technique, eleven eyes of 11 patients, within the age range of 7–28 years with progressive keratoconus went under BLT. Anterior SimK decreased by 5.2D, thinnest location difference was 23um and Kmax reduced by 7.3D. In Zaman technique of BL type I, anterior K value difference was 1.34 D, Kmax reduced by 0.33 D and thinnest location difference was 38um. In Zaman technique of BLT type II, anterior K value difference was 6.5D, thinnest location difference was 96um and Kmax reduced by 15.4D

Old technique has steep learning curve and 10% chances of perforation, conversion to PK, Descemet detachment and chances of acute hydrops. In Zaman technique of BLT type I and II, there is a significant improvement in the BCVA and chances of complications are extremely negligible.