Otago glaucoma surgery outcome study: Long-term results of trabeculectomy—1976 to 1995☆
Section snippets
Setting
The Ophthalmology Department of Dunedin Public Hospital is the center for all public ophthalmic services (including low visual acuity clinic and blind registration) for the province of Otago. This concentration of services in one department, together with the very stable population of this isolated region, has facilitated comprehensive long-term follow-up of patients.
Data collection
The clinical information from the patient records was computerized in 1993 to facilitate data collection and analysis. A
Results
A total of 289 trabeculectomies were performed on 289 eyes of 193 patients. The mean age at operation was 68.8 years (range, 32–90 years). The mean follow-up was 6 years 8 months (range, 1–19 years). Demographic details and details of preoperative status are shown in Table 1. With the exception of four patients (four eyes with uncomplicated operations) who were lost to follow-up 1 to 4 months after surgery, all patients and operations in this series have been accounted for. At the time of
Discussion
This article reports the outcome of a retrospective study of a consecutive series of 293 trabeculectomies performed for the first time on cases of primary open- and closed-angle glaucoma at Dunedin Public Hospital, New Zealand, from October 1976 through August 1996. Pre- and postoperative data from operation to the time of analysis (or time of death) were available on 289 of the 293 eyes (98.5%).
Although this is a retrospective study, the geographic isolation of the population and the
Operative and postoperative complications
The operative and postoperative complications in this series are few and comparable to most previously reported studies.1, 2, 4, 6
Control of IOP
The mean postoperative IOP in this study ranged from 13.6 to 14.9 mmHg over the 19 years of follow-up. The mean postoperative IOPs of most other long-term studies fall within this range.1, 3, 4, 8 The survival curve for control of IOP in this series showed a group of early failures (2.5%), with cases continuing to fail at an average rate of 1.1% per annum over the period of follow-up. Very similar figures are reported in the two studies that most closely match the patient characteristics and
Medications
The proportion of eyes receiving hypotensive medication after trabeculectomy varies considerably across studies, ranging from a low of 1% reported by Watson et al,1 15.9% reported by Mills,8 17.4% (this series), 19% reported by Robinson et al,5 28% by Popovic and Sjöstrand,2 33% by Akafo et al,9 and 49% by Lamping et al.4 It is difficult to account for these wide differences other than to assume that either the populations differ in their response to trabeculectomy or that the criteria for the
Visual field
All the long-term studies reporting visual field behavior after trabeculectomy give similar proportions of eyes showing progressive field loss. Akafo et al9 reported 50% after 7 to 10 (mean, 9.2) years; Watson et al1 report 59% after 1 to 22 (mean, 9.2) years; and in the present study this figure was 19% at 1 to 5 years, rising steadily to 50% by 16 to 19 years (mean follow-up, 6.7 years) after trabeculectomy. In the present series in the subgroup of eyes with more than 10 years follow-up,
Visual acuity
All the long-term studies reporting visual acuity after trabeculectomy show substantial progressive decline in visual acuity with increasing follow-up. Popovic and Sjöstrand2 reported that the mean visual acuity dropped from 0.7 ± 0.3 at operation to 0.3 ± 0.3 at last follow-up (6 to 12 years). Zaidi7 found that the proportion of eyes with 20/40 or better fell from 54% before operation to 25% after 4 years, whereas the proportion with 20/200 or less increased from 21% to 40% over the same
Conclusion
The results of this study confirm those of other, less complete studies—trabeculectomy has a low incidence of surgical complications; it gives good control of IOP in the majority of cases of primary glaucoma; and visual field continues to be lost despite good control of IOP. Furthermore, data on visual acuity demonstrate that the visual acuity falls relentlessly after trabeculectomy to the point that 15 years after operation the probability of the eye not being legally blind is 0.6. This
References (12)
- et al.
Long-term functional outcome after early surgery compared with laser and medicine in open-angle glaucoma
Ophthalmology
(1994) - et al.
Long-term evaluation of initial filtration surgery
Ophthalmology
(1986) - et al.
A critical analysis of the long-term results of trabeculectomy
Am J Ophthalmol
(1979) - et al.
The complications of trabeculectomy (a 20-year follow-up)
Eye
(1990) - et al.
Long-term outcome following trabeculectomyI. Retrospective analysis of intraocular pressure regulation and cataract formation
Acta Ophthalmol (Copenh)
(1991) - et al.
Long-term intraocular pressure control by trabeculectomy; a ten-year life table
Aust N Z J Ophthalmol
(1993)
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Supported by The Healthcare Otago Charitable Trust, Dunedin, New Zealand, and University of Otago Research Committee Otago Research Grant, KNT B01.