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Biomedical subjects

O Nishi

Publications and source records attributed to O Nishi.

At least 73 records · Page 4Linked to original sources
PubMed1989

Pupillary fibrin membrane. A frequent early complication after posterior chamber lens implantation in Japan.

The incidence of pupillary fibrin membrane formation, a relatively frequent complication of cataract surgery in Japan even for experienced surgeons, was noted in 2038 consecutive cases of senile cataract removal and primary posterior chamber intraocular lens (PC IOL) implantation. The overall incidence was 4.4%. Comparisons among cases showed the incidence to be significantly higher among: (1) patients who received dry- versus wet-sterilized lenses (P less than 0.001), (2) eyes with premature, subcapsular, or nuclear cataracts than among those with mature cataracts (P less than 0.05), (3) patients with systemic hypertension (P less than 0.01), (4) eyes not treated postsurgically with topical antiprostaglandins (P less than 0.001), and (5) patients who had undergone previous PC IOL implantation in the fellow eye (P less than 0.001). These findings suggest that the formation of the fibrin membrane is a kind of immunologic reaction. Accordingly, use of antiprostaglandin agents and complete removal of lens material and epithelial cells are recommended, especially for patients undergoing second-eye operations or those with a predisposition to breakdown of the blood-aqueous barrier.

Aged↗
PubMed1989

Lens epithelial cell removal by ultrasound: access to 12 o'clock.

With the ultrasound method for removing lens epithelial cells reported previously, it is difficult to access and remove the cells at the 12 o'clock region. An additional technique for removing these cells is described. The ultrasound tip is placed on the anterior capsule, not underneath it, and ultrasound aspiration is performed. Histological findings show that the region swept once with the tip was completely free of lens epithelial cells. This additional technique allows complete removal of lens epithelial cells from the entire region of the anterior capsule.

Aged↗
PubMed1989

Refilling the lens of the rabbit eye after intercapsular cataract surgery using an endocapsular balloon and an anterior capsule suturing technique.

A new technique for refilling the lens in animal eyes is described. It consists of using a lens-shaped silicone balloon and anterior capsule suturing after intercapsular cataract surgery. The feasibility of the procedure in rabbits is satisfactory and the silicone balloon provides an effective barrier against filling material leakage.

Animals↗
PubMed1989

Intercapsular cataract surgery with lens epithelial cell removal. Part I: Without capsulorhexis.

Endocapsular phacoemulsification or intercapsular cataract extraction with lens epithelial cell removal using an ultrasound technique was performed on 30 eyes. The anterior capsule was not removed after posterior chamber intraocular lens implantation. After a mean follow-up period of 16.4 +/- 2.8 months, anterior capsule opacification was observed in six eyes, posterior synechias in six eyes, and shrinkage of the anterior capsule below the pupillary area, which resulted from the large opening needed for the intercapsular extraction, in 11 eyes. Other postoperative complications caused by lens epithelial cells such as posterior capsule opacification, intraocular lens dislocation, and fibrinous reaction did not occur. These results suggest it is necessary to remove the lens epithelial cells and the anterior capsule after posterior chamber lens implantation in intercapsular cataract extraction.

Adult↗
PubMed1989

Intercapsular cataract surgery with lens epithelial cell removal. Part II: Effect on prevention of fibrinous reaction.

I examined the effect of lens epithelial cell removal using ultrasound and aspiration in intercapsular cataract extraction on the prevention of postoperative complications associated with lens epithelial cells in 110 eyes. Since there was no fibrinous reaction on the intraocular lens in the early postoperative period, I feel the method was effective in preventing this complication. The results suggest that the fibrinous reaction seen several days after posterior chamber lens implantation may be caused by the proliferation of lens epithelial cells.

Adult↗
PubMed1989

Further development of experimental techniques for refilling the lens of animal eyes with a balloon.

Various techniques for experimental refilling of the lens of animal eyes are possible. We describe two new methods: Balloon insertion after endocapsular phacoemulsification and after phacoemulsification with circular capsulorhexis. The feasibility of these techniques was tested in both rabbit eyes and pig cadaver eyes. With organo-silicone gel as the balloon filling material, post-operative refractive changes of up to 4 diopters of residual hyperopia were achieved; accommodation changes were up to -1 diopter. The technique of refilling the lens with a balloon to avoid leakage of filling material warrants further study.

Animals↗
PubMed1989

Automated determination of polygonality of corneal endothelial cells.

We developed a computer program for the image analyzer NEXUS 6400. The program enables automated determination of polygonality, especially hexagonality of corneal endothelial cells, by counting the number of neighboring cells. The results obtained with the method significantly correlated with those determined with the digitizer method.

Aged↗
PubMed1988

Fibrinous membrane formation on the posterior chamber lens during the early postoperative period.

I observed transient membrane formation consisting primarily of fibrin on the anterior surface of the IOL in 45 (7.6%) of the 596 eyes that received posterior chamber lens implantation during the past year. The onset of the condition was generally five to six days after surgery. This membrane characteristically developed between the margins of the anterior capsule, and therefore might be the result of lens-induced uveitis from the proliferation of lens epithelial cells under the anterior capsule.

Adult↗
PubMed1988

Automated morphometry of corneal endothelial cell: use of video camera and video tape recorder.

We developed an apparatus for automated morphometry of the corneal endothelium, which was photographed through a specular microscope connected to a video camera, and the images were stored on a video tape. The clearest stationary image was input into an image analyser to determine automatically the cell boundaries. Although human interaction is generally necessary, the mean time required to complete this procedure was about 13 minutes, based on the results of the 30 normal eyes, and the time needed for manual correction was about 4 minutes. The mean cell area obtained by this method correlated well (r = 0.9335) with that obtained by tracing the same images. This apparatus is clinically useful for immediately obtaining the mean cell area of corneal endothelium and will extend the application of specular microscopy to the routine clinical setting.

Adult↗
PubMed1987

Vitreous loss in posterior chamber lens implantation.

Management of posterior capsule rupture and vitreous loss associated with intraocular lens implantation is described and the results of the procedure statistically analyzed. Vitreous loss occurred in 18 (4.3%) of the 416 eyes treated during a one-year period. Of these 18 eyes, 11 received posterior chamber lenses and seven received anterior chamber lenses; all lenses remained adequately fixated. The visual acuity, incidence of postoperative complications, and endothelial cell loss were not significantly different in the eyes that had posterior capsule rupture and vitreous loss and in the control eyes. Although posterior chamber lens implantation is not necessarily contraindicated in eyes with vitreous loss, instances of high endothelial cell loss suggest the need for greater attention to the endothelial cells during vitrectomy.

Aged↗
PubMed1987

A U-shaped anterior capsulotomy and modified J-loop posterior chamber intraocular lens with new positioning holes.

The procedure used for an anterior capsulotomy is extremely important for successful in-the-bag intraocular lens insertion. An incision line in the extreme periphery may obscure the margin of the residual anterior capsule and make it difficult to confirm the position of the implanted lens. I describe a U-shaped anterior capsulotomy that facilitates in-the-bag insertion, discuss the importance of the location of the positioning holes for proper rotation, and introduce a modified J-loop posterior lens with the positioning holes in an alternative position.

Humans↗
PubMed1987

A new suturing method for the treatment of giant retinal tear.

We report a new method for suturing the retina to the ocular wall when this is required for treatment of retinal detachment due to giant retinal tear. After closed vitrectomy, one of two ski-shaped needles (2.8 mm long and 0.4 mm thick) with an 8-0 nylon thread is introduced from a 1.4 mm scleral incision in the pars plana, advanced under direct observation through the retinal flap, and led extraocularly to an appropriate site in the opposite ocular wall. The second needle is advanced similarly through the same scleral incision and exited from the opposite ocular wall. The thread is then tied extraocularly on the sclera. The retinas of two patients were successfully reattached using this procedure in combination with encircling and the use of SF6 gas and air.

Adolescent↗
PubMed1987

Removal of lens epithelial cells by ultrasound in endocapsular cataract surgery.

A new method was developed to remove lens epithelial cells during endocapsular cataract surgery using a device with a tip that resembles the irrigating-aspirating tip for cortex removal by extracapsular cataract extraction. The tip has an opening on the side and end, both 0.20 mm in diameter, for aspiration. The opening at the end serves to remove the cells at the equator. The top of the tip is sandblasted to provide an abrasive surface. This tip is connected to a phacoemulsifier handle. After nucleus delivery and cortex removal, the tip is inserted beneath the inner surface of the anterior capsule. The cells are detached by the abrasive tip, which vibrates by ultrasound, and then aspirated. Histologic examination revealed that the cells can be removed completely, and that this method is more effective than vacuum cleaning.

Aged↗