ABSTRACT
After the ultrasonic tip is introduced into the highly myopic eye and inflow is activated, the anterior chamber deepens, the lens-iris diaphragm is displaced posteriorly, the iris becomes concave, and the pupil dilates from the weight of the water column above the eye. We define a known but undescribed syndrome--the lens-iris diaphragm retropulsion syndrome (LIDRS)--which is thought to be caused by abnormally loose zonules. The surgeon's reflexive action, lowering the infusion bottle height, reduces the weight of the water column but also reduces the infusion limit. We managed this situation with an inflow-splitting technique in which the infusion bottle height was lowered significantly and a Lewicky chamber maintainer connected to a second infusion bottle at the same height as the first bottle was introduced into the anterior chamber. Pressure monitoring that enabled simultaneous, synchronized recording of phacoemulsification and intraocular pressure fluctuations was used.
Subject(s)
Cataract Extraction/adverse effects , Iris Diseases/etiology , Iris Diseases/therapy , Lens Diseases/etiology , Lens Diseases/therapy , Adult , Aged , Anterior Chamber/pathology , Cataract Extraction/methods , Female , Humans , Intraocular Pressure , Intraoperative Complications , Male , Myopia/complications , SyndromeABSTRACT
Simultaneous two-camera video tracings of phacoemulsification surgery and intraocular pressure fluctuations were made. The fluctuations were transmitted to a quartz pressure transducer through a chamber maintainer that was plugged into the anterior chamber. The transducer was connected to a monitor and recorder calibrated to measure pressure variations between -8.6 and +60 mm Hg. Using common audio for synchronization, the pressure tracings were keyed over the surgical videos and combined in a single film. High, medium, and low inflow volume techniques used by many surgeons exhibiting commensurately higher or lower intraocular pressure fluctuations were scrutinized. Methods to increase inflow volume without a proportionate pressure increase were devised.
Subject(s)
Cataract Extraction/methods , Intraocular Pressure/physiology , Evaluation Studies as Topic , Humans , Hydrostatic Pressure , Isotonic Solutions , Transducers, Pressure , Video RecordingABSTRACT
Experimental phacoemulsification procedures were performed in 54 Rex rabbits. In 96 eyes, posterior chamber intraocular lenses (IOLs) were implanted in the capsular sac, and 12 eyes served as controls with no lens implantation. The IOLs were divided into eight groups consisting of both one-piece and three-piece styles with various optic designs. Each lens was evaluated for the relative effect on posterior capsular opacification (PCO) and optic decentration, two of the most common complications of modern cataract surgery and IOL implantation. Optics with a convex-anterior, plano-posterior design (the type of IOL optic most frequently implanted today) had the highest incidence of PCO. With capsular fixated IOLs, the features that have a statistically significant impact on reducing PCO include (1) one-piece, all-polymethylmethacrylate (PMMA) IOL styles, (2) a biconvex or posterior convex optic design, and (3) angulated loops. Lens decentration was not affected by the optic design, but statistical analysis showed that one-piece, all-PMMA IOL construction provided the most consistent centration.
Subject(s)
Lenses, Intraocular , Animals , Cataract Extraction , Equipment Design , Evaluation Studies as Topic , Lens Capsule, Crystalline , Lenses, Intraocular/adverse effects , Methylmethacrylates , RabbitsABSTRACT
In a prospective randomized study, 25 New Zealand white rabbit eyes were implanted with four intraocular lens (IOL) designs. These included a one-piece modified J-loop IOL, a three-piece modified J-loop IOL, a rigid disc IOL, and an experimental compressible disc (CD) IOL. The CD IOL revealed the lowest mean posterior capsular opacification (PCO) of all IOLs tested (P less than .01). With all lenses tested, a positive correlation between PCO and decentration was found (R = 0.55, P less than .05). These results suggest that because of its design features (i.e., one-piece construction, biconvex optic, posterior angulation of the fixation element), the CD lens produces a mechanical barrier against lens epithelial cell migration and reduces the incidence of PCO.
Subject(s)
Lenses, Intraocular/adverse effects , Animals , Cataract Extraction , Equipment Design , Evaluation Studies as Topic , Lens Capsule, Crystalline/surgery , Lenses, Intraocular/methods , Prospective Studies , RabbitsABSTRACT
A Nd:YAG laser was used to perform posterior capsulotomies on primates in whom one-piece silicone or three-piece polymethylmethacrylate intraocular lenses were in place for more than one year. The eyes were followed for eight weeks after treatment before enucleation. Histologically, no toxic effects caused by the dispersion of any of the biomaterial within the eyes and no significant inflammatory reactions were seen. The silicone lenses used in this study compared favorably with traditional polymethylmethacrylate lenses when posterior capsulotomies with a Nd:YAG laser were performed.
