[Light and scanning electron microscopy of anterior lens capsule following different capsulorhexis techniques]

Aim - to assess the morphology of anterior lens capsules following circular capsulorhexis, for which capsulotomy was either manual or femtosecond (FS) laser produced.

A total of 30 capsular samples obtained during phacoemulsification surgery were studied by light and scanning electron microscopy. All the samples were divided into 3 groups of 10 according to the type of capsulotomy: group 1 - manual, groups 2 and 3 - FS laser produced (with the laser set at high or low energy level, respectively).

In manual capsulorhexis, capsular disk edges were rather smooth all the way round. Rare notches and dents as well as fine burrs up to 4 µm long could only be seen under high magnification. In FS laser capsulotomy groups, under low magnification already, capsular disk edges appeared stepped, stratified, and notched (some notches were up to 20 µm deep). The said changes were more significant following low-energy laser treatment, while high-energy levels were notable for 'melted' disk edges. Regardless of the technique used, all the disks carried a zone of de-epithelization of different width along the free edge.

The differences revealed may result from several factors: 1) less accurate focusing of the laser due to fine torsional eye movements and minimal shape changes of the applanated cornea; 2) peculiarities of FS laser-tissue interaction, particularly, cavitation bubbles that are formed during tissue evaporation and tend to merge, subsequently producing the incision and demarcation line. Moreover, photothermal effects of laser radiation on epithelial cells within the anterior lens capsule cannot be excluded.