Post-operative outcomes in canine eyes receiving a rhexis-fixated prosthetic intra-ocular lens: 30 cases (2014-2020).

OBJECTIVES: To report the outcomes following the insertion of a rhexis-fixated prosthetic intraocular lens (IOL) in dogs undergoing lens removal. MATERIALS AND METHODS: The results are from 30 eyes of 28 dogs, undergoing lendectomy, in which the lens capsule could not accommodate a conventional prosthetic endo-capsular IOL. The reported cases had sustained either spontaneous or traumatic lens capsule rupture, or accidental intra-operative iatrogenic lens capsule disruption, or had required a planned, large, anterior or posterior continuous curvilinear capsulorhexis, all of which precluded insertion of a prosthetic IOL within the lens capsule. An acrylic IOL (XVET; Medicontur) was modified and positioned across the anterior and/or posterior capsulorhexes. RESULTS: Other than haptic luxation in three cases, no complications were seen that were directly attributable to the rhexis-fixated lens. Over a follow-up period from three to 76 months (mean 20.7 months) 26/30 eyes remained visual. Blindness developed in three eyes due to retinal detachment and one eye was enucleated due to regrowth of a ciliary body adenoma. CLINICAL SIGNIFICANCE: Rhexis fixation provided an alternative method to implant a prosthetic IOL when the lens capsule was unable to accommodate a conventional endo-capsular IOL.

Real-time intraocular pressure measurement during phacoemulsification in dogs ex vivo.

This study was performed to evaluate changes in intraocular pressure (IOP) during standard coaxial phacoemulsification using 4 different bottle heights (BHs) and 2 different incision sizes. Coaxial phacoemulsification was performed with a venturi-based machine in 8 enucleated canine eyes through 3.0 and 3.2 mm clear corneal incisions (CCIs). A pressure transducer inserted in the peripheral cornea monitored the IOP in real-time. The surgery was subdivided into 4 stages: sculpt-segment removal, irrigation/aspiration, capsular polishing and viscoelastic removal. The mean IOP and the difference between the maximum and minimum IOPs were calculated at each stage and compared. The ultrasound time and volume of irrigation fluid used were recorded. The mean IOP increased with an elevation in the BH. The mean IOP in the irrigation/aspiration stage was significantly higher than that in the sculpt-segment removal stage at the same BH. The difference between the maximum and minimum IOP at each stage was greater in the 3.2 mm than the 3.0 mm CCIs, although the mean IOP was lower with the 3.2 mm than the 3.0 mm CCIs. The ultrasound time and irrigation fluid volume were greater with the 3.2 mm than the 3.0 mm CCIs. Therefore, fluidic parameters during each stage could be reassessed and adjusted to reduce complications arising from an elevated IOP. Phacoemulsification with 3.0 mm CCIs at a lower BH might lead to less stress on the eye from IOP fluctuations, ultrasound energy and irrigation fluid.

Comparison of 23 gauge and 25 gauge anterior capsulotomy forceps.

In cataract surgery, the most commonly-used procedure for incision of the anterior capsule is continuous curvilinear capsulorrhexis (CCC), developed by Gimbel and Neuhann. As Gimbel has reported, CCC is a safe technique for phacoemulsification and aspiration (PEA) and intraocular lens (IOL) implantation. The optimum incision method for CCC is thought to be that of using anterior capsulotomy forceps. Recently, I have developed the side-port 23 gauge anterior capsulotomy forceps (23G forceps), manufactured by Asico, which can be manipulated via a small incision, as well as the side-port 25 gauge anterior capsulotomy forceps (25G forceps) and 25/23 gauge tapered anterior capsulotomy forceps (tapered forceps), manufactured by Inami, which are thought to provide even better ease of handling. In view of the fact that the visibility, ease of handling, bending, adverse effect on the wound, and effect on the cornea of these various forceps are important, the present comparison study among these forceps was conducted on pig lenses by means of 0.1 % trypan blue staining of the anterior capsule. It was found that capsulorrhexis was difficult with the 25G forceps because of the strong bend of the shaft. However, the tapered forceps has little bend, and like the 23G forceps, it showed outstanding handling and visibility and had little adverse effect on the wound.