Examination Of Phacoemulsification Tips By Atomic-Force Microscopy After Different Numbers Of Cataract Surgeries

Nowadays, cataract surgery is the most commonly performed ophthalmic intervention, and the modern form is phacoemulsification. These surgeries require special equipment, for which there are several alternatives based on the manufacturer’s recommendations. In the present study, we examined and compared manufacturer non-used, only sterilized and single and multiple used phacoemulsification tips after different surgical numbers using with atomic force microscopy

University of Debrecen, Kenézy Hospital Department of Ophthalmology, Debrecen, Hungary

Borsod-Abauj-Zemplen County University Teaching Hospital, Department of Ophthalmology, Miskolc, Hungary

Eötvös Loránd University, Laboratory of Interfaces and Nanostructures , Budapest, Hungary

Phacoemulsifications were performed with five, ten, twenty and thirty times using multiple or single use phaco tips. These were compared with the same number of only sterilized and unused tips using atomic force microscope. The operations were performed by two surgeons, one of them used divide and conquer, while the other used chop technique. During the measurements optical images were taken of the needle edge and mantle. A comparison of geometric flange length and surface and measurable flange length and surface was also performed (profile length %, area %). Roughness values ​​(Sa, Sq) in different size ranges were determined. We also analyzed the differences between the parameters that can be measured during surgery (US ave %, APT, EPT).

Between age and lens hardness(r=0.87, p=0.0045), area% and average phaco time(APT)(r= -0.89, p=0.006), and also between area% and average ultrasound percentage(US ave%)(r=-0.86, p=0.01) were significant correlations. The differences between the two surgical techniques in terms of the area % (p=0.05) and the average US energy used during the operation(US ave %)(p<0.01) were also significant. The tips that were sterilized only once and those that were several times differed significantly in terms of several data(edge ​​Sa: p=0.03, Sq: p=0.05 and mantle Sa: p<0.01, Sa: p<0.01). After 5 operations, the roughness of the samples increased, which decreased with further use, then a jump was during the twentieth operation, and then a decrease again.

During the evaluation of the optical recordings, it became apparent that the roughness on the surface increased with the number of uses. During our measurements with an atomic force microscope, an increase in the edge length can be observed up to the twentieth operation. This can result from scratches and damages then these abrasion and possible material additions. It is apparent that the chop technique causes less damage to the surface of the tip, and less average US energy is required during surgery. Based on all of this, the more times a tip is used, the more its surface is damaged, but perhaps only up to a certain number of operations. In addition, there is less abrasion on the surface of the phaco needle with the chop technique.