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.