Ten year prospective follow-up of a glaucoma operation. The Double Flap Scheie in primary open angle glaucoma

Is glaucoma associated with an increased risk of cataract?

AIMS

The risk of developing cataract in patients with untreated glaucoma or with ocular hypertension was evaluated by comparing the values of lenticular autofluorescence and light transmission in 16 patients with primary open angle glaucoma and 22 patients with ocular hypertension with those of 24 healthy controls.

METHODS

Increase of lenticular autofluorescence and decrease of transmission values in comparison with controls were considered to be precursors of cataract. The values of both variables were determined by fluorophotometry. Each value was normalised for age by dividing it by the value for a healthy control of the same age.

RESULTS

The mean age normalised autofluorescence and transmission values of all patients did not differ significantly from those of the controls (difference < 5%; p = 0.6 and p = 0.2, respectively). Also the mean age normalised autofluorescence and transmission values between glaucoma and ocular hypertension patients did not differ significantly (p = 0.8 and p = 0.9, respectively).

CONCLUSION

The study indicates that untreated primary open angle glaucoma or untreated ocular hypertension do not seem to increase significantly the risk of developing cataract.

Low-dose and high-dose mitomycin trabeculectomy as an initial surgery in primary open-angle glaucoma

PURPOSE

The purpose of the study is to determine the optimum regimen of intraoperative administration of mitomycin as an adjunct to trabeculectomy.

METHODS

Of 11 patients with primary open-angle glaucoma, 22 eyes that had not undergone any surgical intervention were included. In each patient, one eye was randomly allocated to a mitomycin 0.2-mg group and the fellow eye to a mitomycin 0.02-mg group. Mitomycin was applied for 5 minutes only once during trabeculectomy. The follow-up period was 6 to 17 months.

RESULTS

Eleven (100%) eyes in the 0.2-mg group and 7 (63.6%) in the 0.02-mg group achieved successful control of intraocular pressure with or without topical antiglaucoma medication. Transient hypotony maculopathy (18%) and cataract progression (18%) were noted in the 0.2-mg group exclusively. The incidence of other complications was similar between the two groups.

CONCLUSION

These data suggest that the most appropriate dose of mitomycin for primary surgery seems to be in between the two doses tested in the current study.

The development of cataract following trabeculectomy

OBJECTIVE

To determine the risk of cataract development following trabeculectomy.

DESIGN

A prospective follow-up study of patients seen pre-operatively and at one, three, six and 12 months following surgery and subsequently at yearly intervals.

SETTING

Ophthalmology Department of Nottingham University Hospital.

PATIENTS

Fifty-seven patients with primary open angle glaucoma, including pseudoexfoliation, undergoing trabeculectomy.

MAIN OUTCOME MEASURES

Increases in lens opacity measured by the Lens Opacity Meter 701, the Keeler Projectoscopy and clinical grading.

RESULTS

Of 35 patients seen at six months post-operatively, none had lost two Snellen lines of visual acuity due to lens opacity, although three patients showed evidence of increasing lens opacity on all three parameters.

CONCLUSION

There is no evidence of visually significant lens opacity occurring at six months post-operative follow-up.

Results of a filtering procedure in low tension glaucoma

Twenty-six eyes of twenty patients with established low tension glaucoma, who had either a 'double flap' Scheie filtering operation or a trabeculectomy, were followed over a period ranging from one to ten years, with a median of three years. These 26 eyes include two second eyes that served as a contralateral control eye until the visual field deteriorated. All 26 eyes showed progression of visual field defects preoperatively, while postoperatively only 2 eyes showed further progression. Of the 16 nonoperated contralateral eyes, 7 showed progression of visual field defects over the same follow-up period. Two of these 7 eyes had to be operated during the study-period. The difference in progression between the operated and the non-operated eyes was significant (P less than 0.01). The filtering procedure provided a reduction in IOP of 20% or more in 21 of 26 eyes. There was a significant difference in the mean intraocular pressure (IOP) between the operated and the non-operated contralateral eye of 6.8 mmHg (37%) at one year postoperatively. The diurnal variation decreased highly significantly from 4.3 to 2.1 mmHg (P less than 0.001). It is concluded that filtering surgery in low tension glaucoma may result not only in a significant lowering of IOP, but is also effective in slowing further deterioration of the visual fields.

Primary angle closure glaucoma: extracapsular cataract extraction or filtering procedure?

An extracapsular cataract extraction (ECCE) with posterior-chamber-IOL was performed in 21 eyes of 20 patients with primary angle closure glaucoma (PACG; 2 suspects, 5 acute PACG, 14 chronic PACG). The ECCE was performed to improve the IOP. In 14 cases the ECCE was done in lieu of a filtering procedure. After the ECCE the anterior chamber deepened. The mean IOP was reduced from 31 mmHg preoperative to 16 mmHg postoperative. Only 5 eyes needed additional medication after the ECCE. The IOP was reduced even if extensive peripheral anterior synechiae were diagnosed or after failed filtering procedures. The only temporary complication was the IOP-peak in the immediate postoperative period. It is concluded that an ECCE with PC-IOL should be seriously considered as the procedure of choice in PACG instead of a filtering procedure (or instead of a combined procedure).

Glaucoma filtering surgery, a retrospective study of 300 operations

The results of 300 consecutive glaucoma filtering procedures, which were performed in our clinic between January 1982 and September 1985, are described. The overall combined success rate (complete + qualified) was 66.5% (Heuer's classification). This is in good agreement with other glaucoma referral centers. The peak of the age distribution curve at the time of operation was between 70 and 75 years. Nevertheless, 30% of operations was performed on patients under 50 years of age. Relatively poor success rates were obtained in operations following prior unsuccessful filtering surgery (50.5%) or other surgery (47%), in patients under 50 years of age (61%) and in some types of secondary glaucoma. In aphakia/pseudophakia the success rate was 33%. The posterior capsule was intact only 13% of this category at the time of surgery, in 56% previously unsuccessful filtering surgery had been performed, and the age at operation was relatively young (53 yr). These factors have an unfavorable influence on the results of filtering surgery. The success rate in phakic primary open angle glaucoma was 85% and in phakic primary angle closure glaucoma 73%. The combination with a cataract extraction (in 28%) and a peripheral iridectomy, if this had not been performed previously, (in 31%) may have contributed to the relatively favorable surgical results in phakic primary angle closure glaucoma. Relatively high intraocular pressures were found in the early postoperative period; the peak of the pressure-curve was between 20 and 25 mm Hg, 10 mm Hg higher than at the end of follow-up. Postoperative progression of glaucomatous visual field defects was noted in 7%. The most disturbing complication was flat anterior chamber, causing or enhancing cataract formation (in 4 out of 8 phakic patients) and corneal dystrophy (in 2 out of 12 patients). A review of literature is given concerning methods of improving filtration, when the surgical prognosis is poor.