Trabeculectomy training in England: are we safe at training? Two year surgical outcomes

OBJECTIVES

To define the safety profile of trainee trabeculectomy surgery in the United Kingdom. Surgical exposure for trainees in England is limited due to service requirements, the European working time directive constraints and increasing sub-specialisation of glaucoma surgery. Limited knowledge exists on the outcomes of supervised glaucoma surgery. The aim is to determine the safety of supervised trabeculectomy surgery performed by trainee ophthalmologists.

METHODS

Retrospective case note review of all patients that had trabeculectomy surgery with MMC by consultant and trainee surgeons across multiple UK centres. All eyes have 2-year follow up. Success was determined using WGA guidelines. Two-tailed p values were obtained using Fisher's exact test to ascertain statistical significance between groups.

MAIN OUTCOME MEASURES

intraocular pressure, visual acuity, success and failure rates.

RESULTS

324 eyes were reviewed. 211 (66.4%) cases were performed by glaucoma consultants, 107(33.6%) by trainee ophthalmologists. The majority of eyes in each group were undergoing surgery for POAG. Post-operative IOP control showed no significant difference between consultant and trainee groups at year 1 and year 2. Success rates showed no significant difference between consultant and trainee cases. Failure rates at year 1 showed a significant difference between the two groups. No significant difference was seen at year 2. The trainee group had significantly more complications, when compared with the consultant group. Snellen visual acuity loss was not statistically significant between the two groups at the 2 year time point.

CONCLUSIONS

The outcomes of supervised trainee trabeculectomy compare favourably with consultant cases after 2 year follow up. Trainee cases had higher complication rates than consultant cases. Bleb leaks are a common complication of trainee cases, where closer supervision may be required. There is potential for surgical simulation to help increase the success of such cases. These findings may encourage trainee participation in glaucoma surgery.

Portsmouth visual field database: an audit of glaucoma progression

AIM

To explore visual field (VF) progression in a cohort of secondary care-treated glaucoma and ocular hypertensive (OHT) patients.

METHODS

We extracted VFs from our database drawn from our normal clinical practice. VF series from 4177 eyes from 2208 patients who had five or more VFs were obtained, the 'better' eye was selected and the rate of VF progression was calculated using mean deviation (MD) data.

RESULTS

The median rate of progression for the whole sample was -0.1 dB/year (interquartile range (IQR) -4 to 0 dB/year) over a median of 6.7 years (IQR 4.9-8.7). Of 2208 patients, 477 (21.2%) progressed at > -0.5 dB/year; 46 (2.1%) progressed at >-2.0 dB/year. Of those with a 'final MD' of worse than -10 dB (N=244) in their better eye; 14.0% were 'fast progressors' (>-2 dB/year), 33.7% 'moderate progressors' (-1 to -2 dB/year), and 28.8% 'slow progressors' (-0.3 dB to -1 dB/year). Of those with 'initial MD' better than -3 dB and those with worse than -3 dB, 31/1679 (1.8%) and 213/529 (40.3%) respectively, had a final MD of worse than -10 dB.

CONCLUSION

Fast progressors, while important, are relatively rare. Moderate and slow progressors make up the majority of the progressing population within this data set. The risk of significant visual loss is much higher in those with initial damage. With increasing life expectancy, moderate and slow progressors may become increasingly clinically important.

How good are we at advising appropriate patients with glaucoma to inform the DVLA? A closed audit loop

PURPOSE

To establish how good we are as clinicians at advising glaucoma patients with bilateral visual field defects of their legal responsibility to inform the Driver and Vehicle Licensing Agency (DVLA). By using a sticker placed in the patients' notes to highlight driving status and visual fields, we sought to improve our success in providing and documenting this advice.

METHODS

We interviewed and examined the notes of two groups of 100 consecutive glaucoma patients before and after the introduction of a 'driver sticker' placed into patients' notes at the time of visual field testing. We examined the documentation of driving status, and the provision and documentation of advice regarding the DVLA.

RESULTS

In the first audit, we found only 9% of patients had driving status documented. Only 20% of drivers with bilateral field defects were advised to inform the DVLA with 11.4% documentation of this advice. After the introduction of the sticker, we succeeded in improving the documentation of driving status to 99%. We advised and documented the advice to inform the DVLA in 97% of drivers with bilateral field defects.

CONCLUSIONS

We found that as a unit we were poor at documenting driving status and advising glaucoma patients with bilateral field defects to inform the DVLA. By the simple measure of introducing a sticker into patients' notes, we were able to highlight this critical group and improve our provision and documentation of appropriate advice regarding informing the DVLA.

A pilot study of a system for grading of drainage blebs after glaucoma surgery

PURPOSE

To develop and evaluate a novel bleb grading scheme for clinical and photographic evaluation.

METHOD

A system for grading bleb photographs using widely applicable parameters was designed, and reference color photographs printed. A prospective masked agreement study was undertaken comparing slit lamp examination with mono and stereo photographs; 36 eyes of 28 patients with previous glaucoma surgery were graded according to defined parameters on a 1 to 10 scale clinically at the slit lamp by four ophthalmologists and two optometrists. Standardized stereo and mono photographs of the blebs were taken on the same day. The photographs were graded at least one week later in a masked fashion by the same observers, with grading of mono and stereo photographs also separated by one week. Analysis was performed to determine the variability and agreement between slit lamp results and photographic results, and to identify the presence of systematic bias.

RESULTS

High levels of agreement were found between slit lamp and both stereo and mono photographs for vascularity indices, bleb wall thickness, and bleb elevation. Lower levels of agreement were found for the relative components of demarcated versus diffuse areas of the bleb, and for the total width of the bleb. The interquartile range for the median difference between slit lamp and photograph grading was -1.0 to 1.0 for all criteria except diffuse component (-2.0 to 2.0), and the median difference for all scores was 0.0. The median interobserver difference for all criteria was 0.0; the quartile range for all scores was between -0.5 and 1.0 except for diffuse component and width assessments whose quartiles fell in the -1.75 to 1.0 range. Examiners agreed with photographic grading within +/- 1 in more than 80% of gradings for vascularity and bleb height, within +/- 1 in more than 75% of gradings for bleb wall thickness, within +/- 2 in 61% of bleb width assessments, and +/- 2 in 59% of diffuse component.

CONCLUSION

This bleb grading system is reproducible clinically and photographically. High levels of agreement between scores for photographs versus slit lamp examination were found for most categories, with good interobserver agreement for both photograph and slit lamp grading. Further refinement of scoring and reference photographs is required for optimization, especially for grading of bleb morphology.

Evaluating clinical signs in trabeculectomized eyes

AIM

To evaluate interobserver agreement for clinical signs in trabeculectomized eyes when examined face-to-face with slit-lamp biomicroscopy (SL) or by remote examination using telemedicine (real-time remote video imaging; TM).

METHOD

A system for examining trabeculectomized eyes was devised and validated. A prospective randomized interobserver agreement study was then undertaken to compare standard SL biomicroscopy and TM. Remote examination was performed using a 384 kbps Sony 5100 videoconferencing system. Three ophthalmologists each examined 40 eyes of 40 patients, who had previously undergone trabeculectomy. In rotation, two examiners used SL biomicroscopy. The third examined the eye remotely by TM. Analysis was performed to determine the variability in clinical signs and the presence or absence of systematic bias between ophthalmologists and examination methods.

RESULTS

High levels of agreement were observed for paired examinations by SL biomicroscopy (SL/SL) for bleb vascularity (score range 0-10) with no systematic bias. Paired examination by SL and TM (SL/TM) also showed good levels of agreement for bleb vascularity, although the spread of disagreement was wider (95% limits of agreement 2.57 vs 2.98 (P=0.054)). For anterior chamber depth, observers agreed within +/- 10% of anterior chamber depth for 68% of eyes (SL/SL) and 51% of eyes (SL/TM) (P=0.68). Agreement was 'good' for wall thickness (kappa=0.63 +/- 0.08), bleb height (kappa=0.67 +/- 0.1), and the existence of bleb leak (kappa=0.63 +/- 0.19), but poor for bleb morphology (kappa=0.26 +/- 0.12). For the SL/TM comparison, agreement was fair for wall thickness (kappa=0.39 +/- 0.13), poor for bleb height (kappa=0.17 +/- 0.12), good for bleb leak (kappa=0.56 +/- 0.19), and fair for bleb morphology (kappa=0.31 +/- 0.12). Microcysts were not reliably detected using either technique.

CONCLUSION

SL biomicroscopy and TM telemedicine examination may permit reliable clinical assessment of trabeculectomized eyes. However, remote examination with TM is more limited with respect to assessing bleb height and bleb wall thickness. The assessment of bleb morphology and microcysts was unreliable with both instruments. We propose that TM examination of trabeculectomized eyes appears safe and appropriate in situations where face-to-face examination by an ophthalmologist is not practical.

Do selective topical beta antagonists for glaucoma have respiratory side effects?

BACKGROUND/AIMS

Topical beta antagonists are prescribed for glaucoma in approximately 500 000 people in the United Kingdom. The authors have previously shown that topical beta antagonists are associated with an excess incidence of airways obstruction. They examined whether selective topical beta antagonists are associated with excess airways obstruction.

METHODS

A historical cohort study was performed to determine the incidence of airways obstruction in subjects with no previous history of airways obstruction, following treatment with topical beta antagonists for glaucoma for the period 1993-7. Cases were defined as having received a first prescription of a drug specifically used in the management of airways obstruction.

RESULTS

For selective topical beta antagonists 12 of 324 treated subjects developed airways obstruction, compared with 112 of 9094 controls (adjusted hazard rate 3.0 (95% confidence interval (95% CI) 1.6 to 5.4)). For non-selective topical beta antagonists, the corresponding figures were 69 of 2321 subjects compared with the same control group (adjusted hazard rate 2.2 (1.6 to 3.0)). There was no significant difference between groups (p = 0.47, chi(2)), both being associated with a significantly increased risk of airways obstruction.

CONCLUSION

Selective topical beta antagonists do appear to have an excess risk of airways obstruction in this population setting and should be subject to the same prescribing caveats as unselective topical beta antagonists.

Reliability of telemedicine for diagnosing and managing eye problems in accident and emergency departments

OBJECTIVES

To assess the accuracy and efficiency of telemedicine in diagnosing and managing eye problems presenting to accident and emergency departments.

DESIGN

A controlled trial with a face-to-face and telemedicine phases, each involving 40 patients undergoing two consecutive consultations. In the face-to-face phase, both consultations were in person; in the telemedicine phase, observer 1 used videoconferencing technology at 384 kbit/s (separate nonslit lamp-torchlight and slit lamp examinations) and observer 2 saw the patient face to face. Setting The accident and emergency department at Moorfields Eye Hospital.Participants In total, 80 consenting new patients presenting to the department.

MAIN OUTCOME MEASURES

(1) Agreement levels between the two observers for each phase (judged by an independent masked investigator), (2) length of consultation, and (3) number of unnecessary recalls.

RESULTS

Agreement rates were as follows. Face-to-face phase: total agreement (30/40=75%), trivial disagreement (8/40=20%), clinically important disagreement (2/40=5%). Telemedicine phase (torchlight): complete agreement (16/40=40%), trivial disagreement (20/40=50%), clinically important disagreement (4/40=10%). Telemedicine phase (slit lamp): total agreement (23/40=58%), trivial disagreement (15/40=37%), clinically important disagreement (2/40=5%). Agreement levels in the telemedicine phase with torchlight examination were significantly lower (chi(2)=10.07, P=0.007) for any disagreement. Telemedicine consultations erred on the side of clinical caution and were no slower than face-to-face consultations (mean 6 min for observer 1 in both phases). Recalls were more likely (chi(2)=5.16, P=0.02) after telemedicine consultations with torchlight only (9/40) compared with face-to-face consultations (2/40). Although there were more significant disagreements using the telemedicine, in each case the telemedicine diagnosis and management erred on the side of safety; hence, no patient would have suffered by wrong management because of the consultation using telemedicine.

CONCLUSIONS

Telemedicine was found to be an accurate, safe, and efficient method of diagnosing and managing these patients, especially if slit lamp images were used. Advice using telemedicine erred on the side of caution, which resulted in more recalls.

Beta irradiation: new uses for an old treatment: a review

Beta radiation has a long history as a treatment modality in ophthalmology. It is a convenient and practical method of applying radiation and has the advantage of minimal tissue penetration. There has been a recent resurgence in the use of beta radiation in other areas in medicine, such as the prevention of restenosis after coronary artery stenting. Beta radiation has been shown in vitro and in vivo to inhibit proliferation of human Tenon's fibroblasts, which enter a period of growth arrest but do not die. Effects on the cell cycle controller p53 have been shown to be important in this process. In ophthalmology, beta radiation has been used widely for the treatment of pterygium and is under evaluation for treatment of age-related macular degeneration and for controlling wound healing after glaucoma drainage surgery. In this latter role, beta radiation may be particularly appropriate for use in developing countries to improve the results of trabeculectomy while potentially avoiding some of the side effects of other antimetabolites.

Deep lamellar keratoplasty with lyophilised tissue in the management of keratoconus

AIMS

Data are presented on the use of deep lamellar keratoplasty (DLK) using lyophilised donor corneal tissue, in the management of patients with keratoconus (KC).

METHOD

The results of DLK on 44 eyes (42 patients) are reported. The mean patient age was 29.8 years (range 10-56). Mean follow up was 25 months (range 6-100). In seven patients with mental handicap or severe mental illness, the collection of acuity and refractive data was limited.

RESULTS

Perforation of Descemet's membrane (DM) occurred in nine cases (20%). A double anterior chamber formed in five cases, which resolved spontaneously in three patients. Persistent epithelial defects occurred in two cases, one of which necessitated replacement of the graft. The median postoperative uncorrected visual acuity was 6/36. The median corrected postoperative acuity was 6/9. Those with more than 1 year of follow up (n=25) had a significantly better acuity (p=0.015). This group achieved 6/12 or better in 80% (n=20) and 6/6 or better in 40% (n=10). The mean postoperative spherical error was +0.28 (SD 3.49) dioptres (D). The mean refractive cylinder was 3.85 (1.87) D.

CONCLUSION

This detailed retrospective study of DLK for the treatment of patients with KC, with an average follow up of 2 years, highlights the advantages and disadvantages of this technique.

Pharmacological mydriasis and optic disc examination

AIM

To determine whether pharmacological mydriasis leads to a significant difference in interobserver agreement of optic disc measurement compared with examination without mydriasis.

METHOD

A cross sectional study was performed with a pair of observers examining the optic disc of two randomised groups of patients, one group before diagnostic mydriasis, and the other afterwards. Horizontal and vertical disc diameters and cup/disc ratios were measured with a 78 dioptre lens. The study was repeated with another observer pair and two further groups of patients.

RESULTS

In study A 86 subjects were examined in total (52 without and 34 with mydriasis). In study B 87 subjects were examined (45 without and 42 with mydriasis). The 95% limits of agreement of the cup/disc ratio measurement differences were significantly larger without mydriasis (p<0.001 for all studies (F test)). For both studies examination after mydriasis gave significantly greater agreement for vertical and horizontal cup/disc ratios. The cases with good agreement (0.1 difference or better) for vertical cup/disc ratios were 37/52 (72%) and 34 /45 (76%) without mydriasis and 33/34 (97%) and 40/42 (95%) respectively with mydriasis. Similar differences were recorded for horizontal cup/disc ratios. Disc diameter measurement results showed similar differences in study A but were not affected by mydriasis in study B.

CONCLUSIONS

Examination of the optic disc without pharmacological mydriasis gives significantly poorer interobserver agreement. In this study, the mean 95% limits of agreement values for all cup/disc ratio values were 0.27 for examination without mydriasis and 0.13 for examination with mydriasis. A measure outside these limits would suggest a real difference. This study indicates that mydriasis is important for reproducible clinical examination in glaucoma.

Is eye padding routinely necessary after uncomplicated phacoemulsification?

PURPOSE

To investigate the value of eye padding following uncomplicated phacoemulsification under peribulbar anaesthesia.

METHODS

A prospective randomised controlled study was conducted to compare the effect of a conventional eye pad and shield with that of a clear eye shield applied without a pad in 83 patients undergoing routine phacoemulsification under peribulbar anaesthesia without lid block. The primary outcome measures were corneal fluorescein staining, discomfort, diplopia and mobility.

RESULTS

Moderate or severe corneal fluorescein staining on the first post-operative day was significantly more common in the pad and shield group (39%) than in the clear shield group (19%) (p < 0.01). There was no significant difference in post-operative pain as measured either by visual analogue scale or by categorical pain scale. Forty per cent of the clear shield group reported transient post-operative diplopia during the immediate post-operative period compared with 7% of the pad and shield group (p < 0.001). There was no significant difference in reported mobility between the two groups.

CONCLUSIONS

Following phacoemulsification under peribulbar anaesthesia, the use of a gauze eye pad is associated with greater corneal fluorescein staining than a clear plastic shield without pad and offers no reduction in discomfort. A clear shield protects the globe against direct trauma, is associated with reduced moderate to severe corneal staining and facilitates vision in the early post-operative period. Transient diplopia reported by some patients given a clear shield is not disabling and would not be expected to occur in patients with one seeing eye. The use of a clear shield alone is a safe alternative to eye padding and offers important advantages in patients with one seeing eye.

Corneal endothelial specular microscopy following deep lamellar keratoplasty with lyophilised tissue

PURPOSE

To assess the corneal endothelial cell density following deep lamellar keratoplasty (DLK) carried out by air dissection and with the transplantation of lyophilised tissue.

METHOD

Contact endothelial specular microscopy was carried out on a series of patients who had undergone DLK with a minimum of 1 year post-operative follow-up.

RESULTS

Twenty eyes of 18 patients were examined at follow-up times ranging from 1 to 8 years post-operatively (mean 3 years). Indications for surgery were: keratoconus (n = 12), herpes simplex virus (HSV) keratitis (n = 1), herpes zoster ophthalmicus (HZO) keratitis (n = 1), lipid keratopathy (n = 2), lattice dystrophy (n = 1) and corneal scarring (n = 3). Overall, mean post-operative cell density was 2417 cells/mm2 (range 928-3656 cells/mm2). In eyes with pathological conditions not likely to have affected the endothelial cell density, such as keratoconus or lattice degeneration, the mean cell density was 2837 cells/mm2 (range 1030-3656 cells/mm2).

CONCLUSIONS

In patients undergoing DLK for conditions such as keratoconus the post-operative cell density was at a normal level in the majority of cases. Cell loss through this surgical intervention thus appears generally to be small. The prospect for long-term survival of these grafts is good.

Intraocular lens implants and risk of endophthalmitis

AIM

To investigate the possible association between the use of three piece foldable silicone polypropylene (SPP) intraocular lenses (IOLs) and an increased risk of postoperative endophthalmitis.

METHODS

A retrospective analysis was conducted of all cases of postoperative endophthalmitis following phacoemulsification surgery in a single unit over a 3 year period. The incidence of postoperative endophthalmitis in eyes with SPP IOLs was compared with the incidence in eyes with single piece polymethylmethacrylate (PMMA) IOLs.

RESULTS

772 cataract extractions by phacoemulsification were performed. One (0.16%) of the 622 patients with PMMA IOLs developed endophthalmitis. Excluding one patient who had aplastic anaemia, five (3.33%) of 150 patients with SPP IOLs developed endophthalmitis. The relative risk for postoperative endophthalmitis associated with the use of the SPP IOL compared with the PMMA IOL was 20.1 (p = 0.015).

CONCLUSION

This study adds further evidence to the concept that SPP IOLs can be a significant risk factor in the development of postoperative endophthamitis.

A prospective controlled study of a 10/0 absorbable polyglactin suture for corneal incision phacoemulsification

PURPOSE

To evaluate the performance of a 10/0 monofilament absorbable polyglactin suture for temporal 5.2 mm corneal incision phacoemulsification.

METHODS

A prospective randomised controlled study of 49 patients undergoing phacoemulsification with a sutured temporal 5.2 mm corneal section was conducted to compare the refractive results and complications of a 10/0 monofilament absorbable polyglactin suture with 10/0 nylon.

RESULTS

Thirty-eight patients completed the study. There was no significant difference in induced astigmatism between the two groups. All absorbable sutures were intact at 1 week. Six weeks post-operatively the absorbable suture was still intact in 1 (6%) patient, present but broken in 4 (24%) and completely absent in 12 (70%) patients. All polyglactin sutures had been completely absorbed by 12 weeks. Absorption of the polyglactin sutures was associated with mild localised corneal haze in 3(18%) cases (p = 0.055). One of the 18 patients (6%) in the polyglactin suture group presented with iris prolapse associated with knot failure 1 week post-operatively. There was no significant difference in foreign body symptoms between the two groups.

CONCLUSIONS

10/0 polyglactin sutures maintain adequate tensile strength during the immediate post-operative period for small incision surgery and are associated with minimal induction of astigmatism. Their subsequent absorption obviates the need for routine suture removal. Suture absorption is well tolerated although in some cases a mild degree of local tissue reaction raises concern about possible mechanisms of absorption. The risk of knot failure may be reduced by an alternative suture tying technique. 10/0 monofilament polyglactin is an attractive option when a suture is required during small incision cataract surgery.

Sex hormone preparations and retinal vein occlusion

Retinal vein occlusion (RVO) is most commonly seen in middle-aged or older patients and is associated with underlying cardiovascular risk factors. It is much less common in younger patients. Use of the oral contraceptive pill (OCP) is known to be a risk factor for cardiovascular and cerebrovascular disease. There have previously been a few isolated case reports of patients sustaining an RVO whilst taking the OCP. The aim of this study was to investigate patients sustaining an RVO whilst taking the OCP or hormone replacement therapy (HRT). From a large series of 588 patients, we found 11 with an RVO associated with sex hormone preparations. Of these, 6 had taken the OCP and 5 were HRT users. From this large group there were only 9 female patients aged under 35 years who sustained an RVO. Of these, 6 were associated with use of the OCP. All patients were investigated for recognised medical risk factors for RVO. None of these factors were identified in the patients who had used the OCP. Of the patients taking HRT, 4 of the 5 had other potential risk factors. From our large series, the prevalence of RVO in female patients under 35 years taking the OCP was 66%. There is a 30% uptake of the OCP in the general population. These data support the view that RVO is a contraindication to the use of the OCP. Additionally, it would appear (albeit from limited data) that patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.