Biomedical subjects

F Nakao

Publications and source records attributed to F Nakao.

54 records · Page 3Linked to original sources

PubMed1994

Corneal topographic analysis of superolateral incision cataract surgery.

Using corneal topography, we compared the corneal shape changes following superolateral incision cataract surgery with those following conventional superior incision surgery. In our superolateral incision procedure, a 6.5 mm limbal incision was made from the 9 o'clock to 11 o'clock meridians to avoid incising the superior limbus. One hundred four patients were divided into two groups; Group 1 comprised 66 patients who had surgery using the superolateral approach; Group 2 comprised 38 patients who had surgery using the superior approach. The corneas were examined by keratometer and topographic modeling system preoperatively, and at one week and one, three, and six months postoperatively. Keratometric measurements showed that surgically induced astigmatism (SIA) in Group 1 was significantly less than that in Group 2 throughout the six-month observation. The standard SIA deviation in Group 1 was also smaller than that in Group 2, indicating a smaller degree of variability in the superolateral incision surgery. In the corneal topographic analysis, a color-coded map averaging all the Group 1 corneas at each interval showed a slight steepening in the central cornea in the 10 o'clock meridian one week after surgery. This surgically induced steepening disappeared by one month, and the corneal shape recovered its preoperative shape. In contrast, the Group 2 averaged map showed a marked steepening of the upper and lower corneas. The steepening gradually decreased but remained until three months after surgery. Superolateral incision surgery induced a smaller degree of change in the corneal shape, as well as in SIA, than superior incision surgery. The postoperative corneal shape changes disappeared rapidly after the superolateral incision, and the corneal shape soon stabilized and recovered its preoperative shape.

Aged↗

PubMed1994

Corneal endothelial cell loss following phacoemulsification using the Small-Port Phaco.

We studied the extent of corneal endothelial injury after phacoemulsification using the Small-Port Phaco (SPP), a new phacoemulsification instrument that allows linear aspiration during phacoemulsification. Of 72 eyes undergoing phacoemulsification, the SPP was used in 33 (group 1) and a standard phacoemulsification instrument in 39 (group 2). Endothelial cell density was examined by specular microscopy preoperatively and at 1 and 3 months after surgery, and the percentage of endothelial cell loss was evaluated. Operative factors influencing endothelial injury such as the duration of ultrasound emission, the ultrasound power expended, and the amount of irrigating solution used also were measured. The percentages of endothelial cell loss at both 1 and 3 months were significantly less (P < .05) in group 1 than in group 2 (in group 1, 4.3 +/- 3.4% at 1 month, and 5.6 +/- 3.8% at 3 months; in group 2, 6.9 +/- 4.6%, and 8.3 +/- 5.4%, respectively). The duration of emission was shorter and the ultrasound power discharged was smaller in the SPP cases. Since the total ultrasound energy emitted in the SPP cases was less than that in the standard-instrument cases, we conclude that the reduced corneal endothelial damage observed in group 1 was directly related to the smaller total ultrasound power expended in these cases.

Aged↗

PubMed1993

Topographic analysis of early changes in corneal astigmatism after cataract surgery.

Using the Topographic Modeling System (TMS), we studied the early changes in anterior corneal curvature following cataract surgery. Thirty patients who had planned extracapsular cataract extraction (p-ECCE) or phacoemulsification were evaluated with TMS at three days, and one, two, three, and five weeks postoperatively. After p-ECCE, the upper part of the cornea which corresponded to the wound and the lower cornea markedly steepened and showed a bow-tie pattern of astigmatism. Eight (57%) of 14 cases showed little reduction in the corneal steepening at five weeks postoperatively. In five cases (36%) the steepening in the lower cornea was less than the minimal change in the upper cornea. After phacoemulsification, corneal steepening was much less than it was after p-ECCE; three cases (17%) showed almost no surgically induced alteration of the cornea. In eight phacoemulsification cases (61%), postoperative corneal steepening decreased rapidly and the corneal shape recovered within five weeks. Our topographic analysis clearly demonstrated that a smaller wound in phacoemulsification surgery produced less corneal steepening and stabilized more rapidly than a larger wound in p-ECCE.

Aged↗

PubMed1993

Changes in corneal shape after suture cutting using the argon laser for postoperative astigmatism following cataract extraction.

We studied the changes in corneal shape after suture cutting with an argon laser to reduce corneal astigmatism following cataract extraction. Sixty-two patients who exhibited high with-the-rule astigmatism (> 3 diopters [D]) following extracapsular lens extraction had argon laser suture cutting. The patients were classified into three groups: Group A comprised 30 patients whose sutures were cut two to three months after planned extracapsular cataract extraction (p-ECCE); Group B consisted of eight patients who had the same treatment five to nine months after p-ECCE; Group C comprised 24 patients who had the treatment one to two months after phacoemulsification (PE). The dioptric reduction of corneal astigmatism (the percent reduction of astigmatism) was 1.83 +/- 0.98 D (37.4 +/- 18.3%) in Group A, 3.20 +/- 2.35 D (55.6 +/- 34.4%) in Group B, and 2.08 +/- 1.20 D (41.4 +/- 20.4%) in Group C. There was no statistical significance in the dioptric reduction and the percent reduction among Groups A, B, and C. This suggests that the wound size and time of cutting are not directly correlated to the effect of argon laser suture cutting. To examine the relationship between the effect and changes in corneal shape from suture cutting, we divided the patients into two subgroups; one was Subgroup (+) in which the percent reduction of astigmatism was above 25%; the other was Subgroup (-) in which the percent reduction was below 25%.(ABSTRACT TRUNCATED AT 250 WORDS)

Astigmatism↗

PubMed1993

Cancer-associated retinopathy with retinal phlebitis.

A 50-year-old man with cancer-associated retinopathy was investigated using light and electron microscopy, immunofluorescence studies, and western blotting. He had visual disturbance, ring-like scotoma, and night blindness bilaterally. There were narrowed retinal arterioles and dilated retinal venules. Oral corticosteroid therapy had positive effects. Immunostaining using the patient's serum revealed a positive reaction in the ganglion cell layer of normal retina. Western blotting showed that the patient's serum antibody reacted with normal retinal proteins of 24 and 48 kDa. Multiple metastases were evident at autopsy.

Antigens, Neoplasm↗

PubMed1978

Mitosis in the nontumorous parts of the retina with retinoblastoma.

Uninvolved retina in the posterior pole in an enucleated eye was examined by electron microscopy for retinoblastoma. A mitotic figure was occasionally found in the outer and inner nuclear layers. The dividing cells were clearly separated from the tumor mass by 450-600 micrometer. They were identified as immature Müller cells based upon the fine structural features. The existence of the dividing cells in the posterior retina after birth was abnormal and indicated immaturity of the retinal development.

Eye Neoplasms↗

PubMed1975