Childhood glaucoma surgery in the 21st century.

Most children with glaucoma will require surgery in their lifetime, often in their childhood years. The surgical management of childhood glaucoma is however challenging, largely because of its greater potential for failure and complications as compared with surgery in adults. The available surgical repertoire for childhood glaucoma has remained relatively unchanged for many years with most progress owing to modifications to existing surgery. Although the surgical approach to childhood glaucoma varies around the world, angle surgery remains the preferred initial surgery for primary congenital glaucoma and a major advance has been the concept of incising the whole of the angle (circumferential trabeculotomy). Simple modifications to the trabeculectomy technique have been shown to considerably minimise complications. Glaucoma drainage devices maintain a vital role for certain types of glaucoma including those refractory to other surgery. Cyclodestruction continues to have a role mainly for patients following failed drainage/filtering surgery. Although the prognosis for childhood glaucoma has improved significantly since the introduction of angle surgery, there is still considerable progress to be made to ensure a sighted lifetime for children with glaucoma all over the world. Collaborative approaches to researching and delivering this care are required, and this paper highlights the need for more high-quality prospective surgical trials in the management of the childhood glaucoma.

Effect of genotype on chemical composition, ruminal degradability and in vitro fermentation characteristics of maize residual plants.

The objective of this study was to determine the changes to residual plant feeding value of early- and late-maturing maize varieties. The influence of the cell wall carbohydrate composition, in terms of neutral and acid detergent fibre (NDF and ADF) content, NDF and dry matter (DM) degradability, and in vitro organic matter digestibility and gas production on the feeding value of a range of maize genotypes, was measured. The different genotypes were allotted into two maturity groups (MG I--early to mid-early: S210-S240; MG II--mid-late to late: S 250-S280) and harvested at four different harvest dates (depending on the DM content of the kernels). The maize varieties of MG I had lower NDF and ADF contents and higher ruminal DM degradability, in vitro digestibility and gas production and thus a higher feeding value than MG II at the same stage of physiological maturity. A strong negative relationship between NDF content and the ruminal DM degradability (r = -0.81) was observed. The data indicate that the early-maturing varieties permit a larger flexibility in harvesting due to a longer period of starch inclusion into the kernel whilst simultaneously maintaining a good supply of rumen-available fibre. Conclusively, the higher feeding value of the early-maturing varieties, based on lower NDF and high DM digestibility, permits more flexibility in the harvesting period over the later-maturing varieties.

The amino acid composition of rumen-undegradable protein: a comparison between forages.

The objective of this study was to improve knowledge regarding the amino acid profile of the insoluble portion of ingested forage escaping rumen degradation. Six forage categories were analyzed. Categories varied in botanical composition and each contained 2 samples. Samples within categories were derived from the same parent material but differed in harvest, maturity, or conservation type. The rumen-undegradable protein of all forages was measured by incubation for 16h in the rumen of 3 nonlactating cows. All residues were corrected for microbial colonization. The AA profile of the residue was different to the original profile. Degradation trends of individual AA, in terms of increase or decrease relative to the original concentration, were similar between all forages. The AA profiles of forage residues, both within and between categories, were more similar to each other than to their respective original profile. This information may aid in improving the accuracy of estimating postruminal AA supply from forages while decreasing the number of samples required to be analyzed.

The effect of nitrous oxide on intra-ocular pressure in healthy adults.

Many anaesthetic agents affect intra-ocular pressure, yet little is known about nitrous oxide and intra-ocular pressure. This study assessed the effect of nitrous oxide on intra-ocular pressure in 20 healthy adult volunteers. The intra-ocular pressure was measured at baseline, while breathing a 70:30 mix of nitrous oxide and oxygen for 12 min, and then while breathing room air for 15 min. A linear mixed effects model was used to assess change in intra-ocular pressure over time. There was no significant difference in intra-ocular pressure between baseline and during or after nitrous oxide inhalation. Several differences in intra-ocular pressure were noted between internal time-points: pressure increased by 2.4 mmHg between 3 and 6 min of breathing nitrous oxide (p=0.01); it increased by 1.4 mmHg between 3 and 9 min of breathing nitrous oxide (p=0.046); and it decreased by 2.2 mmHg between 6 min of breathing nitrous oxide and 15 min of breathing room air (p=0.035). This study indicates that nitrous oxide inhalation does not significantly change intra-ocular pressure from baseline values in a population of healthy adults.

A randomised, prospective study comparing trabeculectomy with viscocanalostomy with adjunctive antimetabolite usage for the management of open angle glaucoma uncontrolled by medical therapy.

AIMS: To compare trabeculectomy with viscocanalostomy augmented with adjunctive antimetabolite use for the control of intraocular pressure (IOP) in open angle glaucoma (OAG). METHODS: 45 patients (50 eyes) with uncontrolled OAG were randomised to either trabeculectomy (25 eyes) or a viscocanalostomy technique (25 eyes). Preoperatively, all eyes were graded in terms of risk factors for drainage failure and were given intraoperative antimetabolites (5-fluorouracil 25 mg/ml (5-FU), mitomycin C (MMC) 0.2 mg/ml and 0.4 mg/ml) according to a standard protocol. RESULTS: There were no significant differences between the groups in age, sex, type of OAG, preoperative medications, risk factors for drainage failure, and preoperative IOP. Mean follow up was 20 months (range 3-24 months). It was 12 months or longer in all eyes, except two lost to follow up at 3 months. At 12 months, complete success (IOP<21 mm Hg without antiglaucoma medications) was seen in 91% of eyes undergoing trabeculectomy, but in only 60% of eyes undergoing viscocanalostomy (p<0.02). Similarly, at the last follow up visit (mean 20 months) complete success was seen in 68% of eyes undergoing trabeculectomy and 34% with viscocanalostomy (p<0.05). In terms of qualified success (IOP<21 mm Hg with or without glaucoma medications) and mean IOP measurements postoperatively there were no difference between the groups, although the mean number of antiglaucomatous medications required postoperatively was less with trabeculectomy (0.39) than viscocanalostomy (1.04) (p<0.05). Needling procedures were more commonly required after trabeculectomy (p<0.02). YAG goniotomy was required in three eyes (13%) after viscocanalostomy. Early transient complications such as anterior chamber shallowing and encysted blebs were more common in the trabeculectomy group (p<0.05). Late postoperative cataract formation was similar between the two groups. CONCLUSION: In terms of complete success and number of antiglaucomatous medications required postoperatively, IOP control appears to be better with trabeculectomy. Viscocanalostomy is associated with fewer early transient postoperative complications.

National survey of antimetabolite use in glaucoma surgery in the United Kingdom.

AIMS: To assess the pattern of use of antimetabolites in trabeculectomy surgery by all consultant ophthalmologists in the United Kingdom. METHODS: A postal questionnaire of 12 questions regarding antimetabolite use in trabeculectomy surgery was sent to all 749 consultant ophthalmologists in the United Kingdom. The consultants were asked to estimate the number of trabeculectomies they performed per year, how often they used 5-fluorouracil (5-FU) in primary and redo surgery, their usual method of administration of 5-FU, how often they used mitomycin (MMC) in primary and redo surgery, and their usual dosage regimen of MMC. Factors that influenced the decision to use or not use antimetabolites were also assessed. RESULTS: The response rate of consultants returning the questionnaire was 82% (615 out of 749); 87% (533) of these consultants perform trabeculectomy surgery. Of these 533 consultants, 98 (18%) never use an antimetabolite. Most consultants (82%) use antimetabolites, but use them infrequently (only 9% using antimetabolites in more than half their cases). The preferred antimetabolite is 5-FU rather than MMC. Of the 435 consultants performing trabeculectomy surgery and using antimetabolites, 402 (93%) use 5-FU and 179 (41%) use MMC. Various factors influenced the decision to use or not use an antimetabolite, but experience of complications associated with their use was a factor for 34% of consultants. CONCLUSION: The use of antimetabolites, particularly MMC, in the United Kingdom is much less than in America or Japan, where trabeculectomy with MMC is the surgical procedure preferred by glaucoma specialists.

Genetic linkage analysis of a novel syndrome comprising North Carolina-like macular dystrophy and progressive sensorineural hearing loss.

AIM: To characterise the phenotype and identify the underlying genetic defect in a family with deafness segregating with a North Carolina-like macular dystrophy (NCMD). METHODS: Details of the family were obtained from the Moorfields Eye Hospital genetic clinic database and comprised eight affected, four unaffected members, and two spouses. Pedigree data were collated and leucocyte DNA extracted from venous blood. Positional candidate gene and genetic linkage strategies utilising polymerase chain reaction (PCR) based microsatellite marker genotyping were performed to identify the disease locus. RESULTS: The non-progressive ocular phenotype shared similarities with North Carolina macular dystrophy. Electro-oculography and full field electroretinography were normal. Progressive sensorineural deafness was also present in all affected individuals over the age of 20 years. Hearing was normal in all unaffected relatives. Haplotype analysis indicated that this family is unrelated to previously reported families with NCMD. Genotyping excluded linkage to the MCDR1 locus and suggested a potential novel disease locus on chromosome 14q (Z=2.92 at theta=0 for marker D14S261). CONCLUSION: The combination of anomalies segregating in this family represents a novel phenotype. This molecular analysis indicates the disease is genetically distinct from NCMD.

First Report of Petiole Rot of Pulmonaria longifolia Caused by Sclerotium rolfsii var. delphinii.

Sclerotium rolfsii var. delphinii was isolated from the bases of discolored petioles on wilted, yellow leaves of Pulmonaria longifolia (cultivar unknown), an herbaceous perennial growing in a landscape planting in Ames, IA. White mycelia and brick red, 2- to 3-mm-diameter sclerotia were found on affected tissue and nearby soil. The isolates were identified as S. rolfsii var. delphinii based on the formation of dark red, irregularly shaped, >2.0-mm-diameter sclerotia on potato dextrose agar (PDA) around the edge of the culture (1,2). Pathogenicity tests were conducted by inoculating 5-month-old P. longifolia cv. E. B. Anderson growing in 20-cm-diameter pots in a greenhouse at 25 to 30°C. Inoculum was produced by transferring plugs from a 1-week-old culture of the S. rolfsii var. delphinii isolate on PDA to autoclaved carrot disks. After 2 days of incubation, a mycelium-infested carrot disk was placed on the soil surface at the base of each plant. Six plants were inoculated and six plants served as uninoculated controls. All plants were enclosed in plastic bags to maintain high humidity. The pathogenicity test was repeated once. All inoculated plants developed characteristic symptoms within 10 days, whereas all control plants remained symptomless. Sclerotia developed on infected tissue and the media surface, and S. rolfsii var. delphinii was reisolated on PDA from symptomatic petioles. To our knowledge, this is the first report of petiole rot of P. longifolia caused by S. rolfsii var. delphinii. References: (1) Z. K. Punja. Annu. Rev. Phytopathol. 23:97, 1985. (2) Z. K. Punja and A. Damiani. Mycologia 88(5):694, 1996.

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.

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.

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.

Levator palpebrae superioris fibre size in normals and patients with congenital ptosis.

A study of the histochemical staining of levator palpebrae superioris (LPS) was undertaken to measure the muscle fibre size in normal individuals and in patients with congenital dystrophic ptosis in order to see whether there is an alteration in muscle fibre size in congenital ptosis. Eight LPS specimens were obtained: 4 from normal patients (3 from normal levator divided in a bilateral brow suspension procedure and 1 from an exenteration specimen) and 4 from levator resection procedures for treatment of unilateral congenital ptosis. Cryostat sections from these specimens were stained histochemically to reveal muscle fibre types. The orthogonal diameters were measuring using a computer-generated program and the two groups compared using the Mann-Whitney mu-test. No statistically significant difference in muscle fibre diameter was found between normals and patients with congenital ptosis. There was also no change in the distribution or range of muscle fibre diameter in patients with congenital ptosis. Our findings do not support the classification of congenital ptosis as a dystrophy.

Communication and compliance in eye casualty.

PURPOSE: This study aimed to assess patients' perceptions and priorities when consulting doctors in eye casualty, to assess their satisfaction with eye casualty and to evaluate and improve patients' level of knowledge and understanding of their treatment. METHODS: A selected consecutive group of 130 patients presenting to eye casualty between 1 July and 15 September 1995 was interviewed by two of the authors prior to collecting their medication. A further group was interviewed again after collecting their medication from the hospital pharmacist. The hospital pharmacist reiterated treatment details when patients collected their medication. Interviews were conducted by means of a questionnaire. There was no inter- or intraobserver variation. Patients' priorities and perceptions were measured as percentages of the group. Patient satisfaction was measured both by a score on a standardised questionnaire and on a visual analogue scale. Patient recall of treatment details was scored as correct or incorrect. The score prior to and after seeing the pharmacist was compared in those patients who were interviewed after collecting their medication. RESULTS: Among the patients 30.8% considered themselves emergencies, 20.8% were referred and the remainder attended for non-urgent reasons. Eighty-three per cent (83.0%) were wholly satisfied with the consultation. The consultation scored an average of 8.3, SD 1.6, measured on a visual analogue scale of 0-10. When asked the most important aspects of the consultation 54.6% cited treatment, 25.4% reassurance and 20.0% diagnosis. Ninety-six per cent felt that their treatment had been adequately explained; however, 78.3% made errors when reporting their regimen. A significant improvement in patients' level of recall was found after they had received further information from the hospital pharmacist. CONCLUSIONS: Firstly, this study shows patients' perceptions and priorities when visiting eye casualty. Secondly, it demonstrates that patients are generally satisfied with their eye casualty attendance. Thirdly, many patients depart with poor understanding of their eye treatment regime which is likely to affect compliance. Communication between doctors and patients was enhanced by involvement of the hospital pharmacist. This strategy is applicable not only to an ophthalmic casualty unit but also to a wider range of settings and could provide a service standard for future audit.

The effect of prophylactic acetazolamide in patients undergoing extensive retinal detachment repair.

Encirclement of the eye as part of a retinal detachment repair is known to raise the post-operative intraocular pressure. We studied the effect of anticipating this pressure rise by giving perioperative acetazolamide to patients having vitrectomy and encirclement procedures. Two groups (9 with acetazolamide and 14 without) were matched for biographic variables, type of detachment and operation variables. The group given acetazolamide had lower day 1 post-operative intraocular pressures (mean 22.11 mmHg vs 36.36 mmHg, p = 0.002) and were able to go home sooner (mean 1.56 days vs 3.29 days, p = 0.001). No adverse effects of short-term acetazolamide use were noted in this study. We conclude that patients having extensive scleral buckling procedures should all receive prophylactic acetazolamide unless it is specifically contraindicated.