The aged eye's ability to change focus (accommodation) may be restored by replacing the hardened natural lens with a soft gel. Functionalised polysiloxane macromonomers, designed for application as an injectable, in situ curable accommodating intraocular lens (A-IOL), were prepared via a twostep synthesis. Prepolymers were synthesised via ring opening polymerisation (ROP) of octamethylcyclotetrasiloxane (D 4 ) and 2,4,6,8-tetramethylcyclotetrasiloxane (D 4 H ) in toluene using trifluoromethanesulfonic acid (TfOH) as catalyst. Hexaethyldisiloxane (HEDS) was used as the end group to control the molecular weight of the prepolymers, which were then converted to macromonomers by hydrosilylation of the SiH groups with allyl methacrylate (AM) to introduce polymerisable groups. The resulting macromonomers had an injectable consistency and thus, were able to be injected into and refill the empty lens capsular bag. The macromonomers also contained a low ratio of polymerisable groups so that they may be cured on demand, in situ, under irradiation of blue light, in the presence of a photo-initiator, to form a soft polysiloxane gel (an intraocular lens) in the eye. The pre-cure viscosity and post-cure modulus of the polysiloxanes, which are crucial factors for an injectable, in situ curable A-IOL application, were controlled by adjusting the end group and D 4 H concentrations, respectively, in the ROP. The macromonomers were fully cured within 5 minutes under light irradiation, as shown by the rapid change in modulus monitored by photorheology. Ex vivo primate lens stretching experiments on an Ex Vivo Accommodation Simulator (EVAS) showed that the polysiloxane gel refilled lenses achieved over 60% of the accommodation amplitude of the natural lens. An in vivo biocompatibility study in rabbits using the lens refilling (Phaco-Ersatz) procedure demonstrated that the soft gels were biocompatible with the ocular tissue. The polysiloxane macromonomers meet the targeted optical and mechanical properties of a young natural crystalline lens and show promise as candidate materials for use as injectable, in situ curable A-IOLs for lens refilling procedures.

The mechanical properties of the empty lens capsule assessed ex vivo in a lens stretcher remain constant with age, suggesting that the changes in elasticity of the lens capsule do not play a significant role in presbyopia. In young eyes, the lens capsule determines the force necessary to stretch the whole lens. The age-related increase in force needed to stretch the lens is due to changes in the lens contents.

SIBS glaucoma drainage implants did not produce clinically detectable intraocular inflammation in a rabbit model. The 70- and 100-μm SIBS drainage devices demonstrated fewer postoperative complications. IOP levels were not statistically different from control eyes in all groups.

Purpose To compare effective phacoemulsification time (EFX) in femtosecond laser-assisted cataract surgery (FLACS) versus traditional quick chop phacoemulsification (QCP) in senile nuclear cataracts with different densities focusing on soft and hard ones. Patients and Methods A prospective non-randomized comparative study was carried out in Al Watany Eye Hospital and Ain Shams University Hospital, Cairo, Egypt; 250 eyes with senile nuclear cataract (NC) were included and classified into two main groups, FLACS and QCP groups. Each of them was stratified according to nuclear density into three subgroups, subgroups I (Soft NC), II (Medium NC), and III (Hard NC). Sextans-softened fragmentation pattern was performed in the FLACS group. Total EFX utilized for nucleus disassembly and removal was recorded by the completion of each surgery. Results A total of 117 eyes were included in the FLACS group and 133 eyes in the QCP group. No significant difference in EFX was observed between the two groups ( P = 0.228). Regarding subgroups, EFX showed no statistically significant difference between FLACS and QCP ( P = 0.283) in soft NC. For hard NC, a trend to lower values of EFX in FLACS compared with QCP was found, but without statistically significant difference ( P = 0.122). Only in medium NC were significantly lower values obtained in FLACS compared with QCP ( P < 0.0001). Conclusion When compared with QCP technique, FLACS can be used for advantages aside from EFX reduction, including astigmatic keratotomies, accurate sizing, and centration of capsulotomies especially in hard and soft nuclear cataracts. Significant reduction of total EFX with FLACS is most prominent only in medium-density nuclear cataracts.

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