The role of scanning laser polarimetry using the GDx variable corneal compensator in the management of glaucoma suspects

AIM

To determine the role of scanning laser polarimetry using the GDx variable corneal compensator (VCC) in the management of glaucoma suspects.

METHODS

Over a 12-month period, 43 of 447 (9.6%) patients referred to a glaucoma screening clinic were classified as "glaucoma suspects" when it was not possible to categorise the optic disc appearance and visual fields as definitely glaucomatous or definitely normal. Of these patients, 39 underwent a full ophthalmic review, including assessment of the visual fields and analysis of the retinal nerve fibre layer with the GDx VCC.

RESULTS

After the review, 17 of 39 (43.6%) patients were discharged because of normal GDx VCC results. The remaining 22 of 39 (56.4%) were considered to be at risk of developing progressive glaucoma, and further follow-up in the hospital eye service was recommended. 3 (7.7%) patients received treatment. Of the 22 patients, 12 were considered to have pre-perimetric normal tension glaucoma, 7 normal tension glaucoma and 1 primary open-angle glaucoma (POAG). In 19 of these patients, abnormal GDx VCC results were found, particularly inter-eye asymmetry in the nerve fibre layer thickness. However, in 2 of 39 (5.1%) patients the GDx VCC was normal, despite the presence of a neuroretinal rim defect in the optic disc with corresponding visual field loss, and in 1 patient with POAG.

CONCLUSIONS

Scanning laser polarimetry using the GDx VCC is an important tool in defining the management strategies of glaucoma suspects. In screening for glaucoma, however, GDx VCC results should not be used in isolation, but in conjunction with conventional methods of optic disc and visual field assessment.

Direct costs of glaucoma and severity of the disease: a multinational long term study of resource utilisation in Europe

BACKGROUND

Resource utilisation and direct costs associated with glaucoma progression in Europe are unknown. As population progressively ages, the economic impact of the disease will increase.

METHODS

From a total of 1655 consecutive cases, the records of 194 patients were selected and stratified by disease severity. Record selection was based on diagnoses of primary open angle glaucoma, glaucoma suspect, ocular hypertension, or normal tension glaucoma; 5 years minimum follow up were required. Glaucoma severity was assessed using a six stage glaucoma staging system based on static threshold visual field parameters. Resource utilisation data were abstracted from the charts and unit costs were applied to estimate direct costs to the payer. Resource utilisation and estimated direct cost of treatment, per person year, were calculated.

RESULTS

A statistically significant increasing linear trend (p = 0.018) in direct cost as disease severity worsened was demonstrated. The direct cost of treatment increased by an estimated 86 for each incremental step ranging from 455 euro per person year for stage 0 to 969 euro per person year for stage 4 disease. Medication costs ranged from 42% to 56% of total direct cost for all stages of disease.

CONCLUSIONS

These results demonstrate for the first time in Europe that resource utilisation and direct medical costs of glaucoma management increase with worsening disease severity. Based on these findings, managing glaucoma and effectively delaying disease progression would be expected to significantly reduce the economic burden of this disease. These data are relevant to general practitioners and healthcare administrators who have a direct influence on the distribution of resources.

Outcomes of referrals by community optometrists to a hospital glaucoma service

AIM

To determine the outcomes resulting from optometric referrals to a specialist glaucoma screening clinic over a 10 year period.

METHODS

Details of the initial clinical assessment of all new patients referred to the adult glaucoma screening clinic at Oxford Eye Hospital were collected prospectively from July 1994 to June 2004.

RESULTS

Optometrists working in community practice initiated 2505 referrals. Of these, glaucoma was confirmed in 510 patients (20.4%), including 160 with normal intraocular pressure (IOP). A diagnosis of ocular hypertension was made in 747 patients (29.8% of referrals) and 125 (5.0%) were categorised as glaucoma suspects. There was no evidence of a diagnostic trend over the period of data collection. Treatment to lower IOP was commenced in 458 patients (18.3%). Nearly half of those referred, 1148 (45.8%), were discharged from ophthalmological review at the first visit.

CONCLUSION

In this survey, the largest of its nature, only one in five subjects had glaucoma and nearly half were discharged from hospital ophthalmological review. The findings provide a baseline against which the effectiveness of any future system of glaucoma detection in the United Kingdom can be compared.

Normal tension glaucoma is not associated with the common apolipoprotein E gene polymorphisms

BACKGROUND

/aims: In normal tension glaucoma (NTG) factors other than raised intraocular pressure have a role in the pathogenesis of the optic neuropathy. Because particular apolipoprotein E (ApoE) gene polymorphisms have been associated with cell death and survival in neurological degenerative diseases, the purpose of this study was to determine the ApoE allele frequencies in patients with normal tension glaucoma.

METHODS

The apolipoprotein E genotype of 155 patients with normal tension glaucoma was compared to that of 349 non-affected, control subjects from the same geographical area. A similar comparison was made between 53 patients with normal tension glaucoma who demonstrated progressive visual field loss, and control subjects. The frequencies of genotypes was compared with the chi(2) test and Mantel-Haenszel coefficent.

RESULTS

There was no significant difference in the frequency of ApoE alleles or genotypes in the normal tension glaucoma population compared to the control group. The ApoE alleles and genotypes in NTG patients with progressive disease were not different from the control group.

CONCLUSION

ApoE gene polymorphisms are not linked to normal tension glaucoma, suggesting that this gene does not have a role in the pathogenesis of optic neuropathy in this disease.

Long term effect on intraocular pressure of phacotrabeculectomy compared to trabeculectomy

AIM

To compare the long term mean intraocular pressure (IOP) reduction after non-augmented single site phacotrabeculectomy with that after trabeculectomy and to determine the relation between preoperative IOP and IOP reduction.

METHODS

A group of 44 consecutive patients with chronic open angle glaucoma who underwent phacotrabeculectomy were matched to a trabeculectomy control group and the results of surgery were compared. Linear regression analysis of preoperative IOP and IOP reduction was undertaken.

RESULTS

The mean IOP reduction was significantly less in the phacotrabeculectomy group (6.7 (SD 2.1) mm Hg) than in the trabeculectomy group (11.0 (1.4) mm Hg) (p=0.0017). There was a significant difference in surgical success between the groups. The preoperative IOP was significantly related to the postoperative reduction in IOP in both groups (p<0.001).

CONCLUSIONS

In elderly white patients with chronic open angle glaucoma, phacotrabeculectomy is not as effective as trabeculectomy in reducing IOP. In both procedures the magnitude of IOP reduction is proportional to the preoperative IOP.

The National Survey of Trabeculectomy. III. Early and late complications

PURPOSE

There is a considerable body of literature relating to trabeculectomy, however there are no data representative of the national experience of trabeculectomy in the United Kingdom (UK). The Department of Health funded a national survey of trabeculectomy to establish current practice patterns and the outcome of trabeculectomy in the National Health Service (NHS). In this paper we present the reported complications of first-time trabeculectomy from a nationally representative cohort of patients with chronic open angle glaucoma.

METHODS

Cross-sectional study of consultant ophthalmologists performing trabeculectomy in the NHS. Participants recruited their four most recent consecutive first-time trabeculectomy cases with chronic open angle glaucoma according to study eligibility criteria and data were collected by self-administered questionnaire.

FOLLOW-UP

one year post-trabeculectomy.

MAIN OUTCOME MEASURES

occurrence of early and late complications.

RESULTS

Clinical outcome data were available for 1240 (85.3%) of cases. Early complications were reported in 578 (46.6%) cases and late complications in 512 (42.3%) cases. Some cases had more than one complication. The most frequent early complications were hyphaema (n = 304, 24.6%), shallow anterior chamber (n = 296, 23.9%), hypotony (n = 296, 24.3%), wound leak (n = 216, 17.8%) and choroidal detachment (n = 175, 14.1%). The most frequent late complications were cataract (n = 251, 20.2%), visual loss (n = 230, 18.8%) and encapsulated bleb (n = 42, 3.4%). The occurrence of most complications was not associated with a consultant's specialist interest, level of activity, type of hospital or region. Encapsulated bleb was reported more frequently in a university hospital setting.

CONCLUSIONS

The complication rates reported in this paper represent the national experience of first-time trabeculectomy for open angle glaucoma in the UK. These are similar to previous published studies and highlight in particular, the impact of trabeculectomy on visual acuity in the first year following surgery. This survey provides valid and clinically relevant data on the complications of trabeculectomy for the production of guidelines and standards for audit at regional, local and individual level.

Periorbital dermatitis as a side effect of topical dorzolamide

AIM

To report periorbital dermatitis as a late side effect of topical dorzolamide hydrochloride (Trusopt), a drug used to reduce intraocular pressure.

METHODS

A retrospective study of 14 patients who developed periorbital dermatitis while using topical dorzolamide hydrochloride was undertaken. Six patients underwent patch testing for sensitivity to Trusopt, dorzolamide hydrochloride, and the preservative benzalkonium chloride.

RESULTS

The periorbital dermatitis occurred after a mean period of 20.4 weeks of commencing dorzolamide hydrochloride therapy. 13 patients had used preserved topical beta blocker treatment for a mean period of 34.2 months without complication before the introduction of dorzolamide. In eight (57.1%) the dermatitis resolved completely after discontinuing dorzolamide but in six (42.9%) resolution of the dermatitis did not occur until the concomitant preserved beta blocker was stopped and substituted with preservative free drops. Patch testing for sensitivity to Trusopt, dorzolamide hydrochloride, and benzalkonium chloride was negative.

CONCLUSION

These findings suggest that dorzolamide can cause severe periorbital dermatitis. Although the dermatitis may resolve when dorzolamide is discontinued, this does not always occur and in some patients all topical medication containing benzalkonium chloride needs to be stopped.

Combined surgery in the treatment of patients with cataract and primary open-angle glaucoma

The literature on combined surgery in the treatment of patients with cataract and primary open-angle glaucoma was comprehensively studied, and all aspects and variations of the combined procedure were assessed. Phacoemulsification has improved the success rate and reduced the complication rate previously associated with extracapsular cataract extraction combined with trabeculectomy. A mean reduction in intraocular pressure (IOP) of 5 to 8 mm Hg can be achieved. One- and 2-site techniques appear to be similarly effective. Phacotrabeculectomy augmented with mitomycin-C achieves a lower IOP than phacotrabeculectomy alone but has a higher complication rate. The use of 5-fluorouracil is not as effective as mitomycin-C and has a variable influence on the results. The development of new techniques that combine nonpenetrating glaucoma surgery with phacoemulsification offers interesting surgical alternatives, but no long-term results have been reported.

The National Survey of Trabeculectomy. II. Variations in operative technique and outcome

PURPOSE

There is a considerable body of literature relating to trabeculectomy; however, there are no data representative of the national experience of trabeculectomy in the United Kingdom (UK). The Department of Health funded a national survey of trabeculectomy to establish current practice patterns and the outcome of trabeculectomy in the National Health Service (NHS). In this paper we report variations in surgical technique and the national success rate of trabeculectomy.

METHODS

A cross-sectional survey was carried out of consultant ophthalmologists performing trabeculectomy in the NHS. Participants recruited their four most recent consecutive first-time trabeculectomy cases according to study eligibility criteria and data were collected by self-administered questionnaire.

FOLLOW-UP

1 year post-trabeculectomy. Main outcome measure of success: final intraocular pressure (IOP) less than two-thirds the pre-operative IOP. Secondary outcome measures of success: final IOP less than 21 mmHg and visual field stability. Success was further defined as unqualified (excluding patients on anti-glaucoma medications at final follow-up) or qualified (including patients on anti-glaucoma medications at final follow-up). The relationship between variables characterising consultants' practice and main outcome measure was examined by chi-square test.

RESULTS

Clinical outcome data were available for 1240 (85.3%) cases. There were wide variations in operative technique. The mean post-operative IOP was 14.4 mmHg (95% CI 14.2-14.7), which is a mean reduction of 11.8 mmHg (95% CI 11.4-12.2). An unqualified success, in terms of the main outcome measure, was achieved in 66.6% of patients and a qualified success in 71.0% of cases. An unqualified success, in terms of a final IOP less than 21 mmHg, was achieved in 84.0% of cases and a qualified success in 92.0%. Visual fields were stable in 84.2%. Outcome was not related to consultants' specialist interest, level of activity, type of hospital or region.

CONCLUSIONS

The success rates reported in this paper represent the national experience of first-time trabeculectomy for open angle glaucoma in the UK. The national success rate at 1 year compares favourably with many studies in the literature. This survey provides valid and clinically relevant measures of success for the production of guidelines and standards for audit at regional, local and individual level and a baseline for the comparison of new therapies.

Long term results and complications of trabeculectomy augmented with low dose mitomycin C in patients at risk for filtration failure

AIM

To determine the results and complications up to 5 years after trabeculectomy with 0.02% mitomycin C (MMC) in glaucoma patients at risk for failure of filtration surgery.

METHODS

A consecutive series of 21 eyes from 20 patients who underwent trabeculectomy with MMC 0.02%, with an exposure time of 2 minutes, was retrospectively analysed and the results were compared with previously published data.

RESULTS

The mean preoperative intraocular pressure (IOP) was 28 mm Hg on an average of 2.8 glaucoma medications, and the mean postoperative IOP after 3 years was 14 mm Hg on an average of 0.4 medications. Three years after trabeculectomy, 17 of 21 (80.9%) eyes had an IOP of less than 21 mm Hg without medical treatment. Using Kaplan-Meier life table analysis the 5 year probability of an IOP less than 21 mm Hg without medication was 67% and with medication was 90%. Two patients required further glaucoma surgery during the first postoperative year, and another developed hypotonous maculopathy which was reversed after bleb revision. Seven patients developed visually significant cataract as a late consequence of the surgery. There were no bleb related infections.

CONCLUSION

In the long term MMC 0.02% used for 2 minutes intraoperatively is an effective adjunctive treatment in glaucoma patients at risk for bleb failure and in this dose is associated with few complications.

Trabeculectomy with mitomycin C in the treatment of post-traumatic angle recession glaucoma

AIM

The presence of traumatic angle recession is a risk factor for failure of glaucoma filtration surgery and a previous study has suggested that antimetabolite treatment should be used in these patients. This study was undertaken to determine for the first time the mid term results of trabeculectomy with intraoperative application of mitomycin C in patients with post-traumatic angle recession glaucoma.

METHODS

A retrospective analysis was made of 43 consecutive trabeculectomy procedures in 41 young black/mixed race patients followed for a mean period of 25 months (range 2-66 months). Mitomycin C 0.02% was applied between the sclera and conjunctiva for 1-5 minutes at the time of surgery. The intraocular pressure and visual acuity were measured postoperatively. The success of this technique was analysed by using a Kaplan-Meier cumulative survival curve.

RESULTS

The intraocular pressure was successfully controlled at last follow up without topical treatment in 77% (33/43 eyes) and the visual acuity was the same or better in 81% (35/43 eyes). Cumulative probability of success was 85% at 1 year follow up, 81% at 2 years, and 66% at 3 years and thereafter. Hypotonous maculopathy occurred in one patient and no cases of late bleb infection were found.

CONCLUSIONS

In medically uncontrolled post-traumatic angle recession glaucoma trabeculectomy with mitomycin C is an effective surgical procedure with an acceptable complication rate. Good intraocular pressure control and preservation of vision can be expected in most patients.

Neovascular glaucoma as a complication of retinal vasculitis in Crohn disease

PURPOSE

To report a case of neovascular glaucoma as a complication of retinal vasculitis in Crohn disease.

METHODS

Case report with fluorescein angiogram.

RESULTS

A 62-year-old man with biopsy-proven Crohn disease presented with bilateral uveitis, bilateral iris new vessels, and neovascular glaucoma in the left eye. Fluorescein angiography revealed signs of retinal vasculitis and capillary nonperfusion in both eyes.

CONCLUSION

Crohn disease may be associated with retinal vasculitis and, thus, neovascular glaucoma. A satisfactory result can be achieved by using corticosteroids to control the retinal vascular inflammation, by applying panretinal photocoagulation and by controlling the increased intraocular pressure surgically.

Anterior uveitis as a side effect of topical brimonidine

PURPOSE

To report anterior uveitis as a late side-effect of topical brimonidine tartrate 0.2% (Alphagan; Allergan Inc., Irvine, California).

METHODS

Four patients aged 79 to 91 (mean, 83) years, who developed acute anterior uveitis while using topical brimonidine for chronic glaucoma, were clinically evaluated for causes of uveitis. When the inflammation had completely cleared, topical brimonidine was recommenced in one eye only to determine causality.

RESULTS

All four patients developed acute granulomatous anterior uveitis, which resolved rapidly on stopping brimonidine and receiving treatment with topical corticosteroids. The uveitis occurred 11 to 15 (mean, 13.8) months after commencement of brimonidine 0.2% twice daily. None of the patients had a previous history of uveitis, and no other identifiable cause of uveitis was found. In all patients, on rechallenge with brimonidine instilled twice daily to one eye, uveitis recurred within 3 weeks in that eye only.

CONCLUSIONS

These findings suggest that brimonidine can cause anterior uveitis as a late side effect. The inflammation settles rapidly on stopping the medication and on using topical corticosteroids and recurs on rechallenge with brimonidine.

The National Survey of Trabeculectomy. I. Sample and methods

PURPOSE

The National Survey of Trabeculectomy was designed to evaluate current practices of glaucoma surgery in the United Kingdom and to determine the success and complication rates of trabeculectomy on a national basis. This paper reports the survey methods, levels of consultant activity, waiting times, indications for surgery and the demographic and clinical characteristics of the patient sample.

METHODS

Consultant ophthalmologists performing trabeculectomy in the United Kingdom were studied. Four consecutive patients undergoing trabeculectomy under each consultant prior to 18 June 1996 were retrospectively sampled. Patients were followed prospectively and evaluated 6 and 12 months after surgery. Data were collected by self-administered postal questionnaires. To determine the effects of selection and reporting bias a validation study of 14 randomly selected units was also conducted.

RESULTS

Three hundred and eighty-two consultants recruited 1454 eligible patients for analysis. The mean age of patients was 69.2 years (standard deviation 10.9) and 51.7% were male. The underlying diagnosis was primary open angle glaucoma in 89.2%, pseudoexfoliation glaucoma in 5.4%, normal tension glaucoma in 3.8% and pigmentary glaucoma in 1.6%. There was advanced visual field damage in 50.5% of the cohort by the time of listing. The main indications for surgery were failure of medication to control intraocular pressure in 57.1%, progressive visual field loss in 26.5% and progressive optic disc damage in 4.8%. Primary surgery was undertaken in 4.8% of patients. In 80% trabeculectomy was performed within 3 months of listing. However, almost a third of consultants considered individual patient's waiting time too long. Validation studies confirmed that systematic bias did not operate in the selection of patients for the survey or in the reporting of outcomes.

CONCLUSION

The findings of this survey are representative of current practices of trabeculectomy by consultants throughout the United Kingdom and show considerable variation in practice. Failure to control intraocular pressure with topical medications was the main indication for surgery. Advanced glaucomatous visual field damage was present at the time of surgery in half the sample. Though most patients were operated on within 3 months of listing, almost a third of consultants considered the wait unacceptably long.

Siderosis bulbi resulting from an intralenticular foreign body

PURPOSE

To report a case of siderosis bulbi that resulted from a small intralenticular foreign body.

METHOD

Case report.

RESULTS

A 36-year-old man with normal visual acuity and a peripheral intralenticular iron foreign body in the left eye was treated conservatively. Nine weeks after the injury, he had ocular signs of siderosis bulbi, with changes in the electroretinogram. A clear lens aspiration with removal of the foreign body was performed. After removal of the iron foreign body, no progression or regression of the ocular signs of siderosis bulbi has occurred, and the electroretinogram has not changed over a 2-year period.

CONCLUSIONS

Even in the presence of good vision, a patient with an intralenticular ferrous foreign body should be followed closely, and the foreign body should be removed before irreversible siderosis bulbi occurs.

Predisposing factors for chronic angle-closure glaucoma

Chronic angle-closure glaucoma is the commonest form of glaucoma in Sino Mongaloid populations. It is an anatomical disorder of the anterior segment of the eye characterised by permanent closure of part of the filtration angle as a result of iris apposition to the trabecular meshwork. Two pathways lead to this condition: recurrent pupillary block and "creeping" angle closure. East or Southeast Asian ethnic background is an important risk factor for the development of chronic angle-closure glaucoma. Other demographical risk factors include ageing, female gender and a familial tendency. Eyes with chronic angle-closure glaucoma have different anterior segment anatomical relationships when compared to normals. Those eyes at risk tend to be hypermetropic with a shallow anterior chamber, a relatively anteriorly positioned lens and a short axial length. The role of the ciliary body anatomy and ciliary processes in the pathogenesis of this condition requires further investigation.

Electron microscopy findings on an intraocular lens in the uveitis, glaucoma, hyphaema syndrome

PURPOSE

To report the electron microscopic findings on an explanted intraocular lens in a patient with the uveitis, glaucoma, hyphaema syndrome.

METHODS

Scanning and transmission electron microscopy were undertaken on a coccoon of cellular material from the tip of the intraocular lens haptic.

RESULTS

Scanning electron micrographs showed densely packed coccoid-like structures on the haptic surface. By transmission electron microscopy these structures proved to be melanosomes.

CONCLUSIONS

The scanning electron micrographs described in this report are similar to those reported in patients with chronic post-operative uveitis, but to our knowledge have not been shown before in association with the uveitis, glaucoma, hyphaema syndrome. Transmission electron microscopy determined that the coccoid-like structures were melanosomes. The melanosomes are probably derived from damaged pigment epithelial cells or iris stromal melanocytes secondary to recurrent chafing of the haptic against the posterior surface of the iris.

Cavernous-dural fistula with secondary angle-closure glaucoma

PURPOSE

To report a rare case of angle-closure glaucoma, secondary to the rapid development of a choroidal effusion, in a patient with a long-standing cavernous-dural shunt.

METHODS

Case report. Investigations included computed tomographic scan, magnetic resonance imaging, and carotid angiography.

RESULTS

The development of the choroidal effusion occurred because of partial thrombosis of the ipsilateral superior ophthalmic vein and cavernous sinus. Drainage of the choroidal effusion resolved the angle-closure glaucoma.

CONCLUSIONS

The combination of worsening signs and evidence of thrombosis indicates impending resolution of a cavernous-dural shunt. However, if a choroidal effusion causes angle-closure glaucoma, prompt surgical drainage should be considered to prevent permanent peripheral anterior synechiae formation, with the expectation that the effusion will not recur.

Extracapsular cataract extraction with posterior chamber lens implantation in primary angle-closure glaucoma

PURPOSE

To evaluate long-term intraocular pressure (IOP) control after extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (IOL) implantation in patients with primary angle-closure glaucoma.

SETTING

Ophthalmology Department, Groote Schuur Hospital, Cape Town, South Africa.

METHODS

This retrospective study comprised 17 patients (19 eyes) with primary angle-closure glaucoma who had ECCE and posterior chamber IOL implantation. Four presented initially with acute glaucoma, 5 with subacute angle-closure glaucoma, and 8 (10 eyes) with chronic angle-closure glaucoma. In all, less than half the circumference of the angle was permanently closed. The drainage angle was evaluated preoperatively and postoperatively to monitor changes in the amount of angle closure. Intraocular pressure was measured in the early and late postoperative periods.

RESULTS

On the first postoperative day, mean IOP was 17.2 mm Hg, although 5 patients (26%) had an IOP rise above 21 mm Hg despite the use of perioperative topical pilocarpine gel. After a mean follow-up of 19 months, IOP remained below 22 mm Hg without medication in 13 eyes (68%) and with topical medication in 5 eyes (26%). Mean number of glaucoma medications was reduced from 1.5/eye preoperatively to 0.5/eye postoperatively.

CONCLUSION

Cataract extraction with IOL implantation resulted in good long-term IOP control in patients with primary angle-closure glaucoma, suggesting that combined cataract and trabeculectomy surgery may not be necessary to achieve long-term IOP control in these patients.

Duane's retraction syndrome associated with chromosome 4q27-31 segment deletion

PURPOSE/METHOD

A 15-year-old boy with bilateral blepharoptosis, bilateral type 1 Duane's retraction syndrome, and mild learning difficulties underwent chromosomal analysis.

RESULTS/CONCLUSIONS

A de novo deletion of a segment of the long arm of chromosome 4 (4q27-31) was found. To our knowledge, no other individuals with this chromosome deletion have Duane's retraction syndrome. The chromosome defect lies close to the epidermal growth factor gene, 4q25, which was recently linked to Rieger's syndrome. We suggest that families with Duane's retraction syndrome should be assessed for linkage to the area of 4q27-31.

The effect of reducing the exposure time of mitomycin C in glaucoma filtering surgery

BACKGROUND

The use of adjunctive intraoperative mitomycin C has considerably improved the success rate of glaucoma filtering surgery. However, the ideal concentration and exposure time of mitomycin C is unknown. The purpose of this study is to determine whether a satisfactory surgical outcome can be achieved with a lower incidence of adverse side effects by using a shorter exposure time of mitomycin C than has been recommended previously.

METHODS

Twenty-five eyes of 25 consecutive patients who were considered to be at high risk for surgical failure because of their age (< 55 years), previous failure of trabeculectomy, previous cataract surgery, or traumatic glaucoma received a single intraoperative application of mitomycin C (0.2 mg/ml for 2 minutes). They were case-matched with a group of 48 consecutive patients who received a single intraoperative application of mitomycin C (0.2 mg/ml for 5 minutes) by using age, race, type of refractory glaucoma, and preoperative intraocular pressure (IOP) as variables.

RESULTS

Eighteen months after surgery, 22 (88%) patients in the 2-minute group and 21 (84%) patients in the 5-minute group had an IOP less than 21 mmHg with or without treatment. No significant differences were found in the complication rate: in 2 (8%) of 25 eyes of the 2-minute group, chronic hypotony developed compared with 3 (12%) of 25 eyes in the 5-minute group. Hypotony-related maculopathy developed in one eye in the 5-minute group. A cystic bleb was found in 15 (60%) eyes in the 2-minute group compared with 19 (76%) eyes in the 5-minute group, although this difference was not statistically significant. Two (8%) eyes in the 2-minute group and one eye (4%) in the 5-minute group had a bleb-related infection. In one (4%) patient in each group, late severe endophthalmitis developed.

CONCLUSION

These results suggest that a 2-minute intraoperative application of 0.2 mg/ml mitomycin C is as effective as a 5-minute exposure, but the complication rate remains unaltered.

The detection of post-traumatic angle recession by gonioscopy in a population-based glaucoma survey

BACKGROUND

Blunt trauma is responsible for most eye injuries in urban populations. Anterior chamber angle recession has been reported to be the most common sign of previous blunt trauma to the eye. The cumulative lifetime prevalence of post-traumatic angle recession has not been reported previously, and the relation between angle recession and glaucoma in a population-based setting is unknown.

METHODS

As part of a population-based glaucoma survey, gonioscopy was performed on 987 (82.7%) of 1194 inhabitants of the village of Mamre, near Cape Town, South Africa, who were 40 years of age or older.

RESULTS

Some degree of angle recession was identified in one eye of 60 people and in both eyes of 86 people. Men were affected more than three times as often as women in the fifth, sixth, and seventh decades. The cumulative lifetime prevalence of angle recession in this community was 14.6%. The prevalence of glaucoma in people with angle recession was 5.5% (8/146). Of 87 eyes with 360 degrees of angle recession, only 7 (8.0%) had glaucoma. Excessive alcohol consumption was significantly related to the presence of angle recession in women (P < 0.001). The prevalence of monocular blindness due to trauma was 2.5% (25/987).

CONCLUSION

Although the importance of the study may be limited to this community, the findings suggest that future population-based studies of ocular trauma should include gonioscopy on all individuals examined. Secondary glaucomas, especially those related to trauma, should be screened for in developing countries when trying to establish the prevalence of potential visual loss from glaucoma.

The role of ethnicity in primary angle-closure glaucoma

Primary angle-closure glaucoma is significantly more common than primary open-angle glaucoma in the East, whereas in Africa and Europe the reverse is true. In order to study the role of ethnic background in the frequency of primary angle-closure glaucoma in Cape Town and, in particular, in people of mixed ethnic background, the so-called 'coloureds', we retrospectively reviewed all patients with primary glaucoma who attended the glaucoma clinic at Groote Schuur Hospital during a 30-month period. Primary angle-closure glaucoma was diagnosed in 11 of 63 (17%) whites, 11 of 85 (13%) blacks and 114 of 244 (46.7%) coloureds with primary glaucoma; the difference is statistically highly significant (P < 0.001). The human leucocyte antigen frequencies in 97 coloured patients with primary angle-closure glaucoma were similar to those found in a control group of individuals with a similar ethnic background. This study highlights the fact that coloureds are more predisposed to primary angle-closure glaucoma than whites or blacks. Because of their strong historical and genetic ties with south-east Asia, this greater prevalence of primary angle-closure glaucoma might be explained by an Eastern influence on the ocular structures of the eye, as opposed to an African or European influence.

The Dimensions of Eyes with Chronic Angle-closure Glaucoma

The measurement of eyes with primary angle-closure glaucoma has been comprehensively documented in people of European ethnic origin. In comparison, few biometric studies have examined the relationship of one intraocular structure to another in people of Oriental or African ethnic background with primary angle-closure glaucoma. To determine the ocular characteristics of people with this ethnic background suffering from chronic angleclosure glacoma, both eyes of 46 patients with chronic angle-closure glaucoma were measured by contact A-scan ultrasonography, and the measurements were compared with those found in two groups of 23 matched normals. The correlation between the measurements obtained in the right and left eyes in each group was statistically significant (p < 0.001). Although the mean axial length was less (22.43 mm vs. 23.17 and 23.25 mm, p = 0.0001), the mean anterior chamber depth shallower (2.48 mm vs. 2.80 and 2.81 mm, p < 0.001). and the mean "relative lens position'' more anterior in eyes with chronic angle-closure glaucoma compared with normal, the mean lens thickness in all three groups was similar (4.73 mm). These measurements are significantly different from those reported in other ethnic groups. In comparison with the previously reported findings in Europeans, an anterior lens position without significant lens enlargement is responsible for the crowded anterior segment in our patients with chronic angle-closure glaucoma.

Post-traumatic angle recession glaucoma: a risk factor for bleb failure after trabeculectomy

In order to determine if post-traumatic angle recession is a risk factor for failure of glaucoma filtering surgery independent of age or race, the surgical results of trabeculectomy performed in 35 consecutive patients with angle recession glaucoma were compared with those of 35 matched patients with primary open angle glaucoma. A postoperative intraocular pressure of < or = 21 mm Hg (with or without glaucoma medication) was found in 15 of the 35 (43%) patients with angle recession glaucoma compared with 26 of the 35 (74%) patients with primary open angle glaucoma. The long term success of trabeculectomy was significantly worse in angle recession glaucoma when the results were analysed using Kaplan-Meier survival curves. Bleb failure occurred a mean period of 3.1 (SD 1.2) months after trabeculectomy in angle recession glaucoma compared with 9.4 (5) months in primary open angle glaucoma (p < or = 0.001). The finding that posttraumatic angle recession is a risk factor for failure of trabeculectomy, supports the use of antimetabolite therapy to suppress fibrosis after trabeculectomy in these patients.

The prevalence of primary angle closure glaucoma and open angle glaucoma in Mamre, western Cape, South Africa

OBJECTIVE

To determine the prevalence of primary angle closure glaucoma in the so-called Cape people of mixed ethnic background.

DESIGN

A population-based prevalence study.

SETTING

Mamre, a village near Cape Town, South Africa.

PARTICIPANTS

Individuals aged 40 years or older. Historically, their ancestors were Southeast Asians and indigenous Africans and, to a lesser extent, Europeans. Of a total of 1194 people, 987 (82.7%) were examined.

MAIN OUTCOME MEASURE

Primary angle closure glaucoma was diagnosed in individuals with previous acute or intermittent symptoms of angle closure and in individuals with an "occludable" angle and an intraocular pressure of greater than 21 mm Hg or a glaucomatous visual field.

MAIN RESULTS

An age-related trend toward hypermetropia was found, which was greatest in women older than age 50 years. Gonioscopy identified Shaffer grade 1 angles in 89 (9%) of 987 subjects. The prevalence of primary angle closure glaucoma was 2.3% (23 subjects) and increased with age in both sexes. Women were affected more than four times as often as men and the sex difference persisted across all age groups. In comparison, the prevalence of primary open angle glaucoma was 1.5% (15 subjects). Primary glaucoma (angle closure plus open angle) was the leading cause of bilateral blindness in the community, with a prevalence rate of 0.5% (five subjects).

CONCLUSIONS

This study identified primary angle closure glaucoma as a significant public health problem in the Western Cape Province. Because of the ethnic back-ground of the people studied, these findings may also apply to the populations of Southeast Asia.

Presenting features of primary angle-closure glaucoma in patients of mixed ethnic background

The relative frequency with which patients++ present with acute or chronic angle-closure glaucoma depends on their ethnic background. In order to examine the presenting features and effects of primary angle-closure glaucoma in people of mixed ethnicity, we reviewed all 'coloured' patients who presented to Groote Schuur Hospital with this diagnosis during a 5-year period. Of the 92 patients, 33 (36%) presented with acute angle-closure glaucoma and 59 (64%) with chronic angle-closure glaucoma. The level of intra-ocular pressure on presentation correlated well with the number of quadrants of angle closure (correlation coefficient: r = 0.73, P < 0.001). When individual eyes were assessed, a mean cup/disc ratio of > or = 0.8 was present in 35% (65/184) and glaucomatous visual field loss was present in 56.5% (104/184). Total uni-ocular blindness secondary to chronic angle-closure glaucoma, was found in 16 (17%) patients. This study indicates that 'coloured' patients with primary angle-closure glaucoma are more likely to present with chronic symptoms and signs, and that the disease may result in devastating ocular damage and visual loss. In patients of mixed ethnic background with signs of primary glaucoma, chronic angle-closure should be excluded by careful gonioscopic evaluation of the drainage structures of the eye.

Trabeculectomy with mitomycin C for refractory glaucoma in blacks

The use of one intraoperative application of mitomycin C at the filtration site has been effective in eyes at increased risk for failure of routine trabeculectomy. To study the efficacy and safety of this technique in patients with refractory glaucoma, we prospectively examined 30 eyes of 26 black patients in whom a 0.2-mg/ml solution of mitomycin C was applied between Tenon's capsule and the sclera for five minutes before trabeculectomy. The results were compared to those found in a matched group of 30 eyes of 28 patients who underwent trabeculectomy without mitomycin C. The mean postoperative intraocular pressures were significantly lower in the mitomycin C group than in the control group (P = .001). Of the 30 eyes in the mitomycin C group, 25 (83%) had an intraocular pressure of less than 21 mm Hg without glaucoma medication, compared to 11 of 30 (37%) in the control group (P = .00006). In the mitomycin C group, 19 eyes (63%) developed a cystic avascular thin-walled filtering bleb, four eyes (13%) a late positive Seidel test, and one eye slight scleral thinning over the area where the mitomycin C was applied. Although mitomycin C is effective when used in this manner, further study is required to determine the long-term complications.

Molteno tube implantation for neovascular glaucoma. Long-term results and factors influencing the outcome

BACKGROUND

The Molteno implant has been shown to be useful in the treatment of neovascular glaucoma. However, a wide range of success rates has been reported. This is related to the use of differing criteria for success, varying periods of follow-up, and difficulty in quantifying the preoperative condition of the eye.

METHODS

The authors studied the long-term results of the Molteno single-plate implant in 60 eyes with neovascular glaucoma using Kaplan-Meier life-table analysis. Age, visual acuity, underlying retinal diseases, and preoperative retinal ablation treatment were evaluated to establish factors influencing the surgical outcome. The criteria for success included a postoperative intraocular pressure (IOP) of less than or equal to 21 mmHg and maintenance of vision.

RESULTS

The success rate was 62.1% at 1 year, 52.9% at 2 years, 43.1% at 3 years, 30.8% at 4 years, and 10.3% at 5 years. The main causes for failure were loss of light perception in 48% of eyes (29/60), progression to phthisis bulbi in 18% (11/60), and encapsulation of the filtering bleb in 10% (6/60). The long-term surgical outcome was significantly better in patients older than 55 years of age (P = 0.048) and in those with a preoperative visual acuity equal to or better than 6/60 (P = 0.019). Eyes with neovascular glaucoma secondary to diabetic retinopathy had a better prognosis than those with a central retinal vein occlusion (P = 0.003).

CONCLUSION

Although the IOP can be significantly reduced after Molteno implantation, this study suggests that in severely compromised eyes with neovascular glaucoma the main advantage of Molteno implantation is pain relief and avoidance of enucleation.

Surgical management of post-traumatic angle recession glaucoma

PURPOSE

The purpose of this study is to compare the results of three different drainage procedures performed for uncontrolled post-traumatic angle recession glaucoma.

METHODS

A retrospective analysis was undertaken of 87 drainage procedures performed on 65 patients over an 8-year period. The results of trabeculectomy (47 procedures), Molteno single-plate implantation (20 procedures), and trabeculectomy combined with antimetabolite (20 procedures) were compared. Of those treated with antimetabolite, 11 received postoperative subconjunctival injections of 5-fluorouracil and 9 received an intraoperative application of 0.02% mitomycin C to the trabeculectomy site.

RESULTS

In the group undergoing trabeculectomy with antimetabolite therapy, the intraocular pressure (IOP) drop was significantly greater, the percentage of successful cases at 3 and 6 months postoperatively was significantly higher, and the number of postoperative glaucoma medications was significantly lower than the other two groups. No statistically significant differences were found between the groups undergoing trabeculectomy without antimetabolite therapy and Molteno implantation. Of concern were three cases of late bleb infection in the group that received postoperative antimetabolite therapy.

CONCLUSION

In medically uncontrolled post-traumatic angle recession glaucoma, trabeculectomy with antimetabolite therapy is the most effective surgical procedure. However, late bleb infection is a significant risk.

Risk factors for uveitis in sarcoidosis

Uveitis is a potentially sight-threatening complication of sarcoidosis. The object of this study was to determine which patients with sarcoidosis are at greater risk of developing uveitis. We retrospectively assessed 136 patients with clinical, radiological and histological features of sarcoidosis. Of the 48 patients (35.3%) with signs of intra-ocular inflammation, 28 had anterior uveitis, 2 had posterior uveitis and 18 had signs of panuveitis. When patients with uveitis were compared with patients without ophthalmic involvement, no significant demographic, clinical or laboratory differences were found. On linear discriminant analysis, however, the presence of ocular inflammation could be predicted in 32 out of 48 patients (66.6%); age at diagnosis and an elevated serum calcium level were relative risk factors. Awareness of the high incidence of uveitis and education of those at greater risk may result in earlier diagnosis and treatment of ocular inflammation.

Ophthalmic complications after heart transplantation

To ascertain the ophthalmic complications after heart transplantation, the authors reviewed 59 patients who had been referred to the ophthalmology department during a 4-year period and were subsequently followed for at least 1 year. Twenty-five patients (43%) were found to have lens changes in one or both eyes, which is typical of prolonged oral corticosteroid therapy. In three patients (5.2%) posterior subcapsular cataract formation progressed to a level where cataract surgery was required. In two patients (3.4%) cytomegalovirus retinitis developed within 6 months of the transplantation, and significant irreversible visual loss occurred. Retinal vascular changes were found in 22 patients (37.3%), including 18 patients with hypertensive retinopathy and one patient with background diabetic retinopathy. During the period of observation, a central retinal vein occlusion developed in one patient, an anterior ischemic optic neuropathy developed in one patient, and bilateral occipital lobe infarctions developed in one patient. Older patients and those with a longer survival time after transplantation were more likely to have ophthalmic complications (p = 0.04). Although these results indicate a low incidence of sight-threatening complications after heart transplantation, early referral of patients with visual symptoms is important. Those involved with the care of heart transplant patients should be aware of ocular complications secondary to immune suppression and underlying cardiovascular disease.

Proptosis as a presenting sign of extradural haematoma

A conscious 15-year-old boy presented with progressive proptosis and a severe headache 2 weeks after minor blunt trauma to the head. No neurological deficit was present. Computed tomography demonstrated intracranial and intraorbital cyst-like masses. At craniotomy a subacute extradural haematoma was found which communicated with an orbital subperiosteal haematoma through a shelved orbital roof fracture. The haematomas were drained and the patient made an uneventful postoperative recovery. Although rare, an extradural haemorrhage should be considered in any patient presenting to an ophthalmologist with progressive proptosis and headache following a head injury.

The role of trabeculectomy in the treatment of advanced chronic angle-closure glaucoma

To examine the results and complications of trabeculectomy performed for advanced angle-closure glaucoma, a retrospective study was undertaken of 39 patients (46 eyes) who had chronic angle-closure glaucoma and who had undergone trabeculectomy during a 5-year period. The main indication for trabeculectomy was an inability to control the intraocular pressure with glaucoma medication. The surgery was not complicated by visual loss or malignant glaucoma. The intraocular pressure was successfully reduced to <21 mm Hg in 30 eyes (66.7%) without medication and in a further 11 eyes (24.4%) with additional topical glaucoma medication, after a mean follow-up period of 19 months. A second trabeculectomy was required in four patients (8.9%) (mean period: 35.8 months later) and a cataract extraction with intraocular lens implantation was required in nine patients (mean period: 23.9 months later). These results indicate that although trabeculectomy is effective and relatively safe in the management of advanced chronic angle-closure glaucoma, at least one in three patients will require a second operation within 3 years.

Corticosteroid-induced ocular hypertension in draining molteno single-plate implants

Drainage surgery may be required in patients who have previously demonstrated a corticosteroid-induced rise in intraocular pressure. This report presents three patients who had complicated secondary glaucoma and who demonstrated an intraocular pressure increase in response to topical cortico-steroid drugs, despite the presence of a functioning Molteno implant. On discontinuation of the corticosteroid drugs, the intraocular pressure returned to normal levels. Although the mechanism for this observation is unknown, these cases suggest that the trabecular meshwork may still continue to drain aqueous in some patients, despite the presence of bleb over the footplate of a Molteno implant. In predisposed patients who require drainage surgery, Molteno implantation therefore may not prevent the rise in intraocular pressure secondary to the use of topical corticosteroid drugs.

Long-Term Intraocular Pressure Control After Nd-YAG Laser Iridotomy in Chronic Angle-Closure Glaucoma

To evaluate the long-term results of Nd-YAG laser iridotomy, a retrospective study was undertaken of 52 consecutive patients (78 eyes) who had chronic angle-closure glaucoma and who had undergone Nd-YAG laser iridotomy. After a mean follow-up of 22 months, the intraocular pressure was <22 mm Hg without additional treatment in 7 eyes (9%) and with glaucoma medication in 40 eyes (51.3%). At the last follow-up visit, the intraocular pressure was between 22 and 24 mm Hg with an average of two medications in eight eyes (10.2%). Trabeculectomy was required in 23 eyes (29.5%). Those eyes with an intraocular pressure on presentation of >35 mm Hg, or with three or more quadrants of angle closure or with a cup:disc ratio of >0.6, were more likely to undergo trabeculectomy. However, linear discriminant analysis of the ocular findings on presentation revealed that those eyes that underwent trabeculectomy could only have been predicted in 78% and that 36% of eyes identified as being at risk that were subsequently controlled with or without glaucoma medication would have undergone unnecessary trabeculectomy (prediction accuracy: 57%). This study confirms that the current practice of Nd-YAG laser iridotomy, followed if necessary by medical therapy and trabeculectomy, is effective in the management of chronic angle-closure glaucoma. However, careful follow-up of intraocular pressure control and visual field performance is required in patients with advanced disease.

Intravenous sedation for ocular surgery under local anaesthesia

Anterior segment ophthalmic surgery is commonly performed under local anaesthesia. In order to improve patient comfort, a variety of sedation techniques has been employed in the past. The object of this study was, firstly, to determine whether continuous intravenous sedation during surgery offered any advantages in patients premedicated with temazepam and metoclopramide, and, secondly, to compare midazolam to propofol for this purpose. Forty nine patients were randomly allocated to receive no intravenous sedation (n = 15), continuous propofol infusion (n = 17), or continuous intravenous midazolam infusion (n = 17) after peribulbar anaesthesia. Each technique provided cardiovascular and respiratory stability and allowed early recovery with minimal postoperative sequelae. Unexpected ocular field movement occurred more commonly in the patients receiving intravenous sedation, although statistical significance was not shown (p = 0.06). Significantly more patients in the intravenous sedation groups reported amnesia (p = 0.03). Patient acceptability was good irrespective of the technique used. This study suggests that continuous sedation using propofol or midazolam is not beneficial and should be avoided in ophthalmic patients who have received a simple premedication.

Continuous intravenous propofol with nitrous oxide for ocular surgery. A comparison with etomidate, alfentanil, nitrous oxide and isoflurane

Propofol, administered intravenously for induction and as a continuous maintenance anaesthetic with nitrous oxide, was compared, in a group of elderly patients scheduled for ophthalmic surgery, with an anaesthetic technique (etomidate, alfentanil, nitrous oxide and isoflurane) specifically chosen to be haemodynamically stable and evanescent in action. Both techniques resulted in similar effects on blood pressure after induction, intubation and surgical incision, but propofol did not prevent increases in heart rate as effectively at these times. Furthermore, during maintenance anaesthesia, cardiovascular stability and anaesthetic depth were more easily achieved in the group where etomidate, alfentanil and isoflurane were used. Propofol decreased intra-ocular pressure after intubation, while in both groups recovery was rapid with no significant complications. A subgroup of patients receiving alpha-methyldopa had significantly longer post-anaesthetic recovery times.

The association of iridoschisis and primary angle-closure glaucoma

Twelve patients with iridoschisis in one or both eyes were studied to determine the clinical features of the condition and to examine the relationship of iridoschisis to primary angle-closure glaucoma. A spectrum of iris pathology, from subtle intrastromal atrophy to extensive splitting of the anterior layer of iris with fibrillar disintegration, was found in the affected and fellow eyes. Gonioscopy revealed partial or complete angle closure, particularly involving the superior angle, in all patients. Seven had glaucomatous disc damage and five had normal discs. The mean axial length and anterior chamber depth measurements in patients with iridoschisis were similar to those found in matched patients with primary angle-closure glaucoma but were significantly less than the measurements found in matched normals (p < 0.001). This study suggests that iridoschisis is an unusual manifestation of iris stromal atrophy and results from intermittent or acute elevation of intraocular pressure. Primary angle-closure glaucoma should be excluded in patients who present with iridoschisis.