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Biomedical subjects

S Shirato

Publications and source records attributed to S Shirato.

At least 73 records · Page 4Linked to original sources
PubMed1985

Treatment of primary angle-closure glaucoma by argon laser iridotomy: a long-term follow-up.

Argon laser iridotomy was performed in a total of 140 eyes of 104 patients with primary angle-closure glaucoma. A total of 69 eyes were treated by the long-burn technique and followed for an average period of 2.7 years; 71 eyes were treated by the short-burn technique and followed for an average period of 1.7 years. The effects on the IOP control and various factors of glaucoma were similar between both techniques, and the results of iridotomy were analyzed for all eyes. The IOP was controlled at or lower than 20 mmHg in 29% without medication, in 52% with reduced or the same medication as the preoperative treatments, and in 13% with increased medication. However, in 6% the IOP could not be controlled. The incidence of IOP control by iridotomy alone was significantly higher in eyes with peripheral anterior synechia (PAS) less than half the angle circumference than in eyes with more extensive PAS. Visual acuity loss occurred in 51%, and the loss by more than three lines of the acuity chart was seen in 19%; the visual loss was thought to be due to cataract progression or development. No significant differences were found in the visual field, cup-disk ratio, the extent of PAS or tonographic C-value before and after iridotomy. The IOP control and visual acuity loss were comparable with those seen after surgical iridectomy. Because of the absence of significant complications and ease of performance, iridotomy may replace surgical iridectomy in the treatment of angle-closure glaucoma.

Aged↗
PubMed1985

Methods of argon laser trabeculoplasty, complications and long-term follow-up of the results.

Argon laser trabeculoplasty (ALT) was performed on 125 eyes with primary open-angle glaucoma (POAG) and 32 eyes with capsular glaucoma; all eyes were surgical candidates where maximum tolerable medication had failed to control the intraocular pressure (IOP) below 20 mmHg. There were 93 eyes of men and 64 eyes of women, in the age range from 20 to 84 years. Three methods were used: Group 1, 36 eyes treated with about 100 laser shots to the trabecular pigment band over 360 degrees; Group 2, 84 eyes with about 50 shots to the pigment band over 180 degrees; and Group 3, 37 eyes with similar treatment to the anterior part of the trabecular band. The frequency of the initial IOP rise and the maximum postoperative IOP level were in the order of Groups 1, 2 and 3. Other complications, iritis, hemorrhage and peripheral anterior synechiae, were most frequent in Group 1. The success rate of the postoperative IOP control below 20 mmHg with continued medication was analyzed by the life-table method: It was 39 +/- 8% over the period averaging 39 months in Group 1, 66.5 +/- 6% over 17.3 months in Group 2, and 33.7 +/- 15% over 8.1 months in Group 3. The ALT over 180 degrees aimed at the pigment band gave better IOP control with less complications than 360 degrees ALT. The success rate in the eyes of Group 2 was 57 +/- 6% and 94 +/- 6% in POAG and capsular glaucoma, respectively. The IOP distribution after the ALT had a peak at 16-17 mmHg; the IOP was lower than 15 mmHg in about 21% of the eyes. Concurrent IOP measurement and tomography revealed that the IOP reduction after ALT was due largely to a reduction of the outflow resistance in the aqueous outflow channel.

Adult↗
PubMed1985

Trabeculectomy: a prospective study of complications and results of long-term follow-up.

A total of 50 trabeculectomies were carried out with pre- and postoperative medications using steroids and indomethacin, and also with the use of sodium hyaluronate during surgery. The postoperative course was followed by the prospective study protocol adopted by Shirato et al and the results were compared with the Shirato series of 145 trabeculectomies where the surgery was performed without the above medications and without the use of sodium hyaluronate. The shallow anterior chamber and choroidal detachment were less frequent, and the complication-free postoperative course was more frequent in the present than in the Shirato series. The state of the intraocular pressure control of the Shirato series was analyzed by the life-table method for the follow-up period of about 5 years. The final success rate in maintaining the intraocular pressure at or below 20 mmHg after the first trabeculectomy was 60.8 +/- 7.2 (SE) % in primary open-angle glaucoma, 64.2 +/- 12.1% in primary angle-closure glaucoma and 31.1 +/- 9.9% in secondary glaucoma. There were several cases where argon laser trabeculoplasty had been carried out before trabeculectomy. The success rate in these cases appeared to be no different from the rate in the rest of the eyes. In primary open-angle glaucoma, the second surgery after failed first trabeculectomy gave a similar success rate as the first surgery, but the third surgery after two failed trabeculectomies gave a very low success rate. The intraocular pressure distribution after one year showed a frequency of visual field deterioration was high in the order of the eyes with the intraocular pressure higher than 20 mmHg, those with 15-20 mmHg and those with lower than 15 mmHg.

Actuarial Analysis↗
PubMed1984

[The technic of argon laser trabeculoplasty and its results].

Argon laser trabeculoplasty (ALT) was performed on 130 eyes with primary open-angle glaucoma or capsular glaucoma. Three different methods of ALT were employed to determine if the methods itself affects the incidence of immediate postoperative rises in intraocular pressure (IOP). Thirty-five eyes received 100 burns over 360 degrees of the posterior trabecular meshwork; these were categorized as Group 1. Group 2 comprised 77 eyes given 50 burns over 180 degrees of the posterior meshwork. Group 3 consisted of 18 eyes treated with 50 burns over 180 degrees of the anterior trabecular meshwork. The duration of each burn was 0.2 s in Group 1 and 0.1 s in Groups 2 and 3. The power of each burn ranged from 700 to 1000 mW in each group. Immediate postlaser IOP rise was defined as a pressure elevation exceeding prelaser value by 5 mmHg or more. In Group 1 the incidence of IOP rise was 82%; it was 58% after the first session in Group 2, but only 22% in Group 3. A sustained, marked pressure rise was most frequently observed in Group 1 as compared with the other two groups. Other complications, including sustained iritis, peripheral anterior synechiae and hyphema, were seen most frequently in Group 1 and least frequently in Group 3. Successful control of IOP, defined as an IOP of less than 20 mmHg, was achieved in 37% in Group 1, 70% in Group 2 and 56% in Group 3. The follow-up period ranged from 1.5 to 52 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Glaucoma, Open-Angle↗
PubMed1984

Goniotomy with Q-switched Nd-YAG laser in juvenile developmental glaucoma: a preliminary report.

Goniotomy using Nd-YAG laser was carried out in 8 eyes of 6 cases with juvenile primary developmental glaucoma, in one eye with primary congenital glaucoma, in one eye with Axenfeld's anomaly and in one eye with Sturge-Weber syndrome. The chamber angles of these eyes showed various degrees of trabeculodysgenesis, and the laser shots placed anterior to the end of the iris insertion separated the iris tissue from the trabecular band. The angle circumference over 3 to 8.5 hours with an average of 4.8 hours could be treated by one session of the laser treatment in 8 eyes and by two sessions in 3 eyes. In cases with juvenile primary developmental glaucoma, the intraocular pressure (IOP) could be controlled below 20 mmHg with antiglaucomatous medication in 5 eyes by one session and in 2 eyes by two sessions of the laser treatment, but the IOP was not controlled in one eye. In the eye with primary congenital glaucoma aged 41 years and the eye with Sturge-Weber syndrome, the treatment failed to control the IOP. In the eye with Axenfeld's anomaly, the IOP was controlled with reduced medication. The postoperative complications embraced iritis, anterior chamber hemorrhage and IOP rise, but they left no serious consequences. Nd-YAG laser goniotomy may be useful for the treatment of juvenile primary developmental glaucoma.

Adolescent↗
PubMed1984

Effects of laser trabeculoplasty on the human aqueous humor dynamics: a fluorophotometric study.

Thirteen eyes, seven with primary open-angle glaucoma and six with capsular glaucoma, were treated with laser trabeculoplasty (a fluorophotometric examination was performed about one week prior to it). The intraocular pressure was reduced below 20 mm Hg in eight eyes, and the second fluorophotometric examination could be carried out in six successfully treated eyes about three months later. In the six successfully treated eyes, the pre-laser trabeculoplasty examination showed the following results: IOP: 22 +/- 2 mm Hg; the cornea-aqueous transfer coefficient for fluorescein: 0.32 +/- 0.10 hour-1; and the aqueous flow rate: 1.31 +/- 0.53 microliter min-1. The post-laser trabeculoplasty examination gave the following results: IOP: 15 +/- 2 mm Hg; the cornea-aqueous transfer coefficient: 0.29 +/- 0.08 hour-1; and the aqueous flow rate: 1.23 +/- 0.41 microliter min-1. No significant difference was found in the aqueous flow rate or the cornea-aqueous transfer coefficient before and after.

Adult↗
PubMed1982

Use of Fieldmaster automated perimeter for the detection of early visual field changes in glaucoma.

The efficacy of automated suprathreshold perimetry with Fieldmaster automated perimeter (model 101 PR and 200) was evaluated in the screening for very early glaucomatous visual field defects which failed to be detected with kinetic perimetry using a Goldman perimeter. Evaluation of 117 eyes with elevated intraocular pressure revealed a small, relative defect in the central field in 14 eyes which was confirmed by static perimetry with a Tübinger perimeter. Although Fieldmaster model 200 is equipped with more target positions than model 101 PR, detectability of early defects was almost identical between two models. Automated suprathreshold perimetry with either model of Fieldmaster perimeter is useful in detecting the early changes which may be missed by kinetic perimetry with a Goldman perimeter. Based on the difference in the false positive rate (45.6% with model 200 vs 26.7% with model 101 PR) the screening with 101 PR seems to be more rewarding.

Adult↗
PubMed1982

Effects of N-demethylated carbachol on intraocular pressure and pupil in ocular hypertensive patients.

The effects of N-demethylated carbachol on intraocular pressure and pupil size were studied in 18 ocular hypertensive patients. Topical administration of N-demethylated carbachol in 9%, 15% and 30% solutions has been demonstrated to bring about miosis which was found to be dose-dependent. No significant change of intraocular pressure clearly attributable to this drug has been demonstrated.

Administration, Topical↗
PubMed1982

Argon laser trabeculoplasty in open-angle glaucoma.

Argon laser trabeculoplasty (LTP) was carried out, along the whole circumference of the trabecular band (WC-LTP) in 45 eyes and along half the circumference (HC-LTP) in 20 eyes with open-angle glaucoma. A pronounced rise of the intraocular pressure (IOP) occurred in 74% of the WC-LTP eyes, usually within 6 hours. An initial IOP rise was found to occur in 64% of the HC-LTP eyes, usually within 2 hours. The maximum IOP level was similar after both techniques, but the duration of the IOP rise was significantly shorter after the HC- than after the WC-LTP. The IOP after 24 hours was at or higher than 25 mmHg in 42% of the cases after the WC-LTP and in 10% after the HC-LTP. During the follow-up for 7-38 months after the WC-LTP 22 out of 45 eyes showed failure of IOP control below 21 mmHg: the majority of failure took place within one week. An analysis by a life-table method showed that the final probability of control after 38 months was about 48%, and that the failure of control occurred in only a few eyes after the IOP had been under control for a period of 6 months. The rate of IOP control was the following day was lower than 25 mmHg. The eyes treated by the HC-LTP were followed only for a short time, but the results appeared promising. Since the HC-LTP shows less complications than the WC-LTP, the long-term results of HC-LTP need to be evaluated for possible routine use.

Actuarial Analysis↗
PubMed1982

Argon laser iridotomy in angle-closure glaucoma: a comparison of two methods.

Argon laser iridotomy was performed in a total of 141 eyes with angle-closure glaucoma, using a modified contact lens of Abraham, by means of two methods, both comprising two-step burns of the iris. While the first-step burns were carried out under similar conditions in both methods, the duration of the second-step burn was 0.2 seconds in Method I (long-burn technique) and 0.02 seconds in Method II (short-burn technique). Iris perforation was achieved in one session in 91% of 101 eyes by the former and in 100% of 40 eyes by the latter technique. Both techniques caused a transient elevation of the intraocular pressure (IOP), but it subsided within 24 hours. Retrobulbar injection of lidocaine or instillation of timolol or indomethacin oil drops did not suppress the IOP rise. Also, iritis was seen in all cases, but it disappeared within one week. No anterior chamber hemorrhage nor retinal hazard was encountered. Corneal clouding was mild and rare by the short-burn technique, permitting iridotomy to be carried out in the iris periphery of the upper quadrants. By the long-burn technique, however, the corneal clouding often prevented continued laser irradiation. A comparison with the results of the conventional peripheral iridectomy revealed that the present short-burn technique is a safe and efficient procedure for the treatment of angle-closure glaucoma.

Adult↗
PubMed1982

A critical analysis of the trabeculectomy results by a prospective follow-up design.

Trabeculectomy was carried out 145 times on 113 eyes of 100 patients, with primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG) or secondary glaucoma. The complications of this surgery found during the follow-up period from 0.5 to 3 years were analyzed according to the preplanned protocol. The shallow anterior chamber (AC), i.e. AC depth being less than half of the depth before surgery, was found in 51.7%, flat AC, i.e. iridocorneal contact from the periphery to the pupillary margin, in 15.9%, hyphema in 17.9% and choroidal detachment in 33.9%. The shallow AC usually disappeared within several days and only in 2.8% was this complication prolonged over one week. The choroidal detachment disappeared within 3 days in most cases, and in only 0.7% was surgical intervention required for its treatment. Progression of cataract, as defined by diminution of the visual acuity more than 2 lines of the acuity chart, was found in 38.6%. The choroidal detachment and cataract progression were significantly more frequent in eyes with the shallow AC. Simple statistics gave a figure of about 70% for the rate of IOP control below 21 mmHg. A life-table analysis gave the 2-year success probability of about 57% in POAG after the first trabeculectomy. After repeating the procedure twice in the same eye, the success probability was about 37%, but after 3 or more repeated operations it was only 10% after one year.

Adolescent↗