7†Scoping review of homonymous hemianopia in childhood.

Cerebral visual impairment (CVI) encompasses a heterogeneous group of disorders and a spectrum of types of visual impairments. Research is needed to characterise the different forms of CVI and identify the specific needs of these groups to inform individualised patient care. Homonymous hemianopia (HH) is a definable visual field defect that affect some children with CVI. As part of a new research programme, we conducted a scoping review of the literature on HH in children and young people to map current knowledge and identify evidence gaps.We used the PRISMA extension for Scoping Reviews methodology. Multiple online databases were searched using terms associated with 'homonymous hemianopia' and 'children'. This yielded 1588 papers which were screened by two reviewers. Of these 1001 were excluded at abstract screen and a further 415 excluded after full text review, with full text unavailable for 15. Data were extracted and charted from 157 studies and additional grey literature.Interim analysis shows reported studies are predominantly from high income countries with a paucity of higher-level evidence, and a preponderance of case reports. Most papers reported causative pathology and diagnosis of HH. There was minimal attention to or evidence relating to intervention. Child-specific grey literature on HH was limited.This review collates the current evidence-base for HH in children. It demonstrates the important evidence-gap relating to intervention in these cases that would help inform more individualised care. Similar scoping reviews may be prove useful in assessing the evidence relating to other definable groups within the CVI umbrella.

Seroprevalence and epidemiological correlates of HTLV-I infection in U.S. blood donors.

Screening for human T-lymphotropic virus type I (HTLV-I) antibodies was performed on sera from 39,898 blood donors at eight blood centers in geographically distinct areas of the United States. Ten donors (0.025 percent) showed evidence of HTLV-I seropositivity by enzyme immunoassays; this was confirmed by protein immunoblot and radioimmunoprecipitation. Seroprevalence rates ranged from 0 to 0.10 percent at the locations sampled, with HTLV-I antibodies found predominantly in donors from the southeastern and southwestern United States. Matched case-control interviews and laboratory studies were performed on five seropositive women and two seropositive men who participated in an identity-linked collection of sera from a subset of 33,893 donors at six of the eight blood centers. Four of the women and both men are black; one woman is Caucasian. Four of the seven seropositive individuals admitted to prior intravenous drug abuse or sexual contact with an intravenous drug user. Sexual contact with native inhabitants of an HTLV-I endemic area was the only identified risk factor for one male. The distribution of HTLV-I antibodies in this U.S. blood donor sample corroborates the previously reported epidemiology of this agent and suggests that additional donor screening measures, including the testing of donated blood for HTLV-I markers, may be necessary to prevent the spread of HTLV-I to transfusion recipients.

Outcome of retinoblastoma in east Africa.

We estimated the proportion of patients reaching a pediatric ophthalmology unit (Comprehensive Community Based Rehabilitation for Tanzania Disability Hospital, CCBRT) or an oncology unit (ORCI) in east Africa and investigated presentation, histology, and treatment outcomes of patients with retinoblastoma. A 5-year retrospective study identified 91 patients, representing approximately 18% of the nationwide total. Mean lag time was 10 months (standard deviation (SD) = 17) and mean follow-up was 8 months (SD = 11, range 0-40, n = 91). Thirty months disease-free survival probability was 0.23 (standard error = 0.07). Outcomes for retinoblastoma in Africa remain poor. The data presented here suggest strategies for improving the outcomes, including encouraging earlier presentation and establishment of multi-disciplinary treatment centers.

Polyol permeability of the human red cell. Interpretation of glucose transport in terms of a pore.

The kinetic equations describing transport through a pore that has a binding site and that undergoes a conformational change are identical to those of a carrier model. Therefore, in order to distinguish between the two models it is necessary to test specific predictions based on detailed mechanistic models. A pore model is described in which the substrate (glucose) is able to reach the single binding site only from the outside when the pore is in conformation I and only from the inside when it is conformation II. On the basis of this model it is predicted that solutes which do not have any specific affinity for the binding site should still have a finite permeability via the glucose transport system if they are the same size or smaller than glucose. This permeability should be proportional to the volume of distribution of the solute in the pore and should therefore decrease with increasing molecular size. A geometric pore volume can be estimated from this size dependence. In order to test these predictions, the glucose-dependent permeability of a series of 4-carbon (erythritol), 5-carbon (D-arabitol, L-arabitol and xylitol) and 6-carbon (D-mannitol, D-sorbitol and myo-inositol) polyols was measured. The permeability of all the polyols is decreased by the presence of glucose and the KI of this "inhibitable" component is similar to that D-sorbose, suggesting that this component is associated with the glucose transport system. Since these observations could be explained entirely in terms of a specific affinity for a carrier binding site, they do not exclude a carrier mechanism. However, as predicted for the pore model, this "inhibitable" permeability decreased with increasing molecular size and the calculated geometric pore volume was of a size that would be expected for a cell membrane pore.

Long term outcome of trichiasis surgery in the Gambia.

BACKGROUND: Trichiasis surgery is believed to reduce the risk of losing vision from trachoma. There are limited data on the long term outcome of surgery and its effect on vision and corneal opacification. Similarly, the determinants of failure are not well understood. METHODS: A cohort of people in the Gambia who had undergone surgery for trachomatous trichiasis 3-4 years earlier was re-assessed. They were examined clinically and the conjunctiva was sampled for Chlamydia trachomatis polymerase chain reaction (PCR) and general bacterial culture. RESULTS: In total, 141/162 people were re-examined. Recurrent trichiasis was found in 89/214 (41.6%) operated eyes and 52 (24.3%) eyes had five or more lashes touching the globe. Corneal opacification improved in 36 of 78 previously affected eyes. There was a general deterioration in visual acuity between surgery and follow up, which was greater if new corneal opacification developed or trichiasis returned. Recurrent trichiasis was associated with severe conjunctival inflammation and bacterial infection. C trachomatis was detected in only one individual. CONCLUSIONS: Recurrent trichiasis following surgery is a common potentially sight threatening problem. Some improvement in the cornea can occur following surgery and the rate of visual loss tended to be less in those without recurrent trichiasis. The role of conjunctival inflammation and bacterial infection needs to be investigated further. Follow up of patients is advised to identify individuals needing additional surgical treatment.

Primary open-angle glaucoma presentation at a tertiary unit in Africa: intraocular pressure levels and visual status.

AIM: To investigate the presentation of POAG at a tertiary referral hospital in East Africa, including intraocular pressures, visual status and management decisions. METHODS: Retrospective review of first-time presenters with POAG over a 6-month period. RESULTS: Of the 298 patients identified, mean age 57 years (n = 296, range = 14-88, SD = 14), 213 (72%) male, 122 (41%) had normal vision (using WHO better eye acuity criteria: visual impairment < 6/18, blind < 3/60) at presentation, 87 (30%) had visual impairment and 86 (29%) were blind. The mean presenting IOP was 32 mmHg (SD = 11) and 70% of the patients had a cup:disc ratio of 0.8 or worse in the better eye. Longer disease duration (OR = 1.20, 95% CI 1.04-1.39) and higher mean IOP (OR = 1.06, 95% CI 1.02-1.10) were associated with visual impairment or blindness. Intraocular pressure showed a negative linear correlation with presenting logMAR acuity (R(2) = 0.115, SE = 1.30, p < 0.0005). The mean IOP in eyes that had undergone trabeculectomy (19 mmHg, SD = 8, n = 17) was significantly (p < 0.0005) lower than that in eyes that had not (34 mmHg, SD = 12, n = 274). The referral rate for trabeculectomy was 158/275 (57%). Male sex (OR = 2.17, 95% CI 1.0-4.72), higher mean IOP (OR = 1.09, 95% CI 1.05-1.14) and not being blind (OR = 26.47, 95% CI 9.90-70.78) were associated with surgical referral. Of the 158 patients, 76 (48%) accepted surgery. CONCLUSIONS: A high proportion of patients presenting to our unit with POAG are visually impaired or blind and the higher their presenting IOP the poorer their visual acuity. Previous trabeculectomy was associated with lower IOPs and protection from visual impairment and blindness. Further training of clinic staff towards early surgical referral and investigation of gender barriers is required.

Operational comparison of single-dose azithromycin and topical tetracycline for trachoma.

PURPOSE: World Health Organization guidelines for antibiotic treatment of trachoma currently include a 6-week course of tetracycline eye ointment twice daily or a single dose of oral azithromycin. Previous trials have shown similar efficacy of these two alternatives when administration of the ointment was carefully supervised. It is believed, however, that azithromycin may be a more effective treatment in practice, and the purpose of this study was to test that hypothesis. METHODS: A masked randomized controlled trial was conducted to compare azithromycin and tetracycline under practical operational conditions-i.e., without supervision of the administration of the ointment. Three hundred fourteen children aged 6 months to 10 years with clinically active trachoma were recruited and individually randomized to receive one of the two treatments. Follow-up visits were conducted at 10 weeks and 6 months. The outcome was resolution of disease (clinical "cure"). RESULTS: Children allocated to azithromycin were significantly more likely to have resolved disease than those allocated to tetracycline, both at 10 weeks (68% versus 51%; cure rate ratio, 1.31; 95% confidence interval [CI], 1.08-1.59; P = 0.007) and at 6 months (88% versus 73%; cure rate ratio, 1.19; 95% CI, 1.06-1.34; P = 0.004). Azithromycin was particularly effective for intense inflammation (P = 0.023, Fisher's exact test). CONCLUSIONS: Single-dose oral azithromycin was a more effective treatment for active trachoma than tetracycline ointment as applied by caregivers. The high cure rate achieved with tetracycline in this study in the absence of supervision and the significantly higher costs of azithromycin, suggest that in the absence of donation programs, switching routine treatment from tetracycline to azithromycin would not be a good use of resources.

A cytolytic human T lymphocyte clone differentially recognizing HLA-B27 subtypes.

A cytolytic human T cell (CTL) clone, designated F/M-F159, has been produced, the lytic specificity of which distinguishes subtypes of HLA-B27. This was demonstrated in cell-mediated lympholysis (CML) assays of: 1) a panel of target cells from unrelated donors, 75 B27 + and 36 B27-; 2) six families, including 20 B27 + and 14 B27- individuals; and 3) B27 + and B27- variants of a B27+ lymphoblastoid cell line (LCL). Specificity of F/M-F159 for HLA-B27 was confirmed by blocking studies with monoclonal antibodies. Lysis of B27 + targets reactive with the anti-B27 monoclonal antibody B27M2 was 30-104%, while lysis of B27 +, B27M2- targets was 4-22%. Lysis of B27- targets expressing HLA-Bw47, known to be cross-reactive with the B27M2 antibody, was 10 to 19%, while lysis of all other B27- targets was less than or equal to 10%. Clone F/M-F159 lysed B27 + targets, and failed to lyse B27- targets, irrespective of the clinical status of the cell donors. It is concluded that F/M-F159 recognizes an epitope present on the majority of serologically identified HLA-B27 molecules and that this epitope is closely related to, but not identical with, the epitope recognized by the antibody B27M2. These findings are interpreted as supporting a direct role for HLA-B27 in disease pathogenesis.

Red blood cell substitutes and artificial blood.

Artificial substitutes for specific functional portions of blood are being developed. Perfluorocarbons have received the most publicity in recent years, and one, Fluosol-DA, is undergoing clinical trials in the United States. The perfluorocarbon emulsions physically dissolve oxygen, which distinguishes them from the chemical binding that occurs in hemoglobin. Fluosol-DA has been shown to transport oxygen in amounts that are probably clinically useful if the patient inspires an atmosphere with increased oxygen. A large clinical trial from Japan suggests that Fluosol-DA is safe to transfuse, although recent work suggests that Fluosol-DA may produce significant pulmonary reactions that can be prevented by steroid administration. These reactions are probably caused by complement activation by an emulsifying agent in Fluosol-DA. Recent applications of Fluosol-DA include use in a resuscitative fluid, use in occlusive vascular disease, an special applications, such as treatment of carbon monoxide poisoning, which take advantage of the solubility properties of perfluorocarbons.

An ultrasound based classification of periocular haemangiomas.

AIMS: To propose a classification system for periocular haemangiomas based on ultrasound evaluation. METHODS: Retrospective review of ultrasound images from children seen in the authors' unit with periocular haemangiomas. Static ultrasound images from 50 patients with periocular haemangiomas were reviewed as identified from a computerised database. Each haemangioma ultrasound image was classified into three categories: (1) preseptal only; (2) preseptal + extraconal; (3) preseptal + extraconal + intraconal. These were compared with the categories given to each patient at first presentation after dynamic scanning. RESULTS: Classification was possible from the static images in 44 (88%) cases. Of those classified 20 (45%) were preseptal only; 17 (39%) were preseptal + extraconal, and seven (16%) had an additional intraconal component. The classification in all 44 cases was the same as that given at the time of presentation. In the small number of cases which went to surgery or had neuroimaging, the ultrasound classification was confirmed. CONCLUSIONS: Ultrasound classification was not difficult to perform and no child needed sedation or general anaesthesia for this exam. Ultrasound anatomical classification is an important first step in determining appropriate treatment of periocular haemangiomas. The authors present what they believe to be the first such classification.

An inner city preschool visual screening programme: long-term visual results.

AIMS: The aim of this study was to investigate the long-term outcome of the treatment of amblyopia as a sequel to preschool screening, which has not hither-to been described. METHODS: All patients originally referred from a preschool screening programme were recalled for examination by letter. 255 patients were reviewed at least 4 years after discharge of which 88 were definitely amblyopic at presentation and 107 were not amblyopic at presentation and were used as controls. RESULTS: 79% of the amblyopes improved or maintained visual acuity after discharge but this was reduced to 42% after an age induced increase (estimated from the controls) was compensated for. The mean drop in visual acuity in the amblyopic eyes which deteriorated was 0.23 (SD 0.15) logMAR units. Stepwise multiple linear regression showed that the best single predictor of post-discharge deterioration in visual acuity was the improvement in visual acuity seen during treatment (R2 = 19%). Eccentric fixation at time of follow up (increasing R2 to 47%) and good presenting acuity (further raising R2 to 57%) contributed additional information, and were both associated with greater post-discharge deterioration in visual acuity. CONCLUSIONS: The majority of amblyopes who attended for follow up maintained or improved their visual acuities after discharge. Those patients who demonstrated deterioration of their amblyopia had usually improved well during the programme and were often fixating eccentrically at follow up.

Traumatic wound rupture after penetrating keratoplasty in Africa.

AIM: To investigate risk factors, visual outcome, and graft survival for traumatic wound rupture after penetrating keratoplasty. METHODS: A retrospective analysis of 336 patients who underwent penetrating keratoplasty from 1988 to 1995. RESULTS: 19 patients (5.7%) suffered traumatic postoperative wound rupture requiring surgical repair. They were younger (mean age 16.6 years, 95% CI 13.2-20.6) and more frequently keratoconic (p = 0.01) than other patients (mean age 28.9 years, 95% CI 26.-31.0). Mean postoperative follow up was 37.7 (SD 22.9) months and 24.5 (18.9) months for the rupture and non-rupture patients. Mean interval between keratoplasty and rupture was 18 (21) weeks. The lens was damaged and removed in 37% of ruptured eyes. For keratoconics, the probability of graft survival at 5 years was lower (p = 0.03) in the ruptured eyes (75%) than in the non-ruptured eyes (90%). Endothelial failure was a more common (p <0.05) cause of graft opacification in ruptured grafts than in intact grafts. Of the ruptured eyes, 53% achieved a final corrected acuity of at least 6/18 and 63% achieved at least 6/60 compared with 48% and 71% of the intact eyes respectively (both p >0.1). The proportion of keratoconic eyes which achieved at least 6/60 was lower (p = 0.02) in the ruptured eyes (67%) than the non-ruptured eyes (87%). Eyes with wound ruptures of 5 clock hours or greater were less likely (p <0.05) to achieve an acuity of 6/18 and were more likely (p <0.05) to have an associated lens injury. CONCLUSIONS: Graft rupture is relatively common in African practice, particularly in young keratoconics. Visual outcome and graft survival are not significantly worse than for other grafted eyes, but are significantly worse than for other grafted keratoconic eyes.

Longitudinal study of trachomatous trichiasis in the Gambia.

AIM: Investigation of the natural history of trachomatous trichiasis in the Gambia and of the outcome of self epilation and surgery for the condition. METHODS: A 1 year longitudinal study of 190 subjects with trichiasis was performed. Major trichiasis cases (five lashes or more) were referred for surgery and minor trichiasis cases were advised to epilate. Outcome measures included progression of trichiasis and corneal scarring; attendance for and results of surgery. RESULTS: 34 of 148 (23%, 95% CI 16 to 31) subjects with major trichiasis attended for surgery over the year. Progression from minor to major trichiasis occurred in 18 of 55 subjects (33%, 95% CI 21 to 47). Progression of corneal scarring occurred in 60 of 167 patients (36%, 95% CI 29 to 44). Clinically active trachoma and conjunctival bacterial isolation predicted progression of corneal opacity. Surgery was successful in 39 of 54 (72%) eyes. CONCLUSIONS: Despite the overall decline in trachoma in the Gambia, patients with both minor and major trichiasis remain at risk of developing corneal opacity. Active trachomatous inflammation and additional infection with bacteria may accelerate this process. Antibiotic treatment for trichiasis patients (in addition to surgery) should be investigated. Surgery for minor trichiasis may be indicated. Regular audit of surgical results is necessary with retraining where needed.

Epidemiological, demographic, and economic analyses: measurement of the value of trichiasis surgery in The Gambia.

AIM: Untreated trichiasis can lead to corneal opacity. Surgery to prevent the eyelashes from rubbing against the cornea is available, but many individuals with trichiasis never undergo the operation. This study estimates the cost of illness of untreated trichiasis and the willingness to pay for surgery and compares them with the actual cost of providing surgery. MATERIALS AND METHODS: The cost of illness estimate is based on trichiasis patient demographics. Data on the implicit price of obtaining surgery and surgical utilization in a matched pair randomized trial are used to infer individual willingness to pay for trichiasis surgery. Patients in the study paid nothing out-of-pocket for surgery; the price of obtaining surgery is the value of the individual's time needed for travel and surgery plus the price of public transportation. The cost of producing surgery was calculated from project records. RESULTS: All monetary figures are reported in 1998 US dollars. The average cost of untreated trichiasis, or the net present value of life-time lost economic productivity, was $89. Individuals facing a lower cost were more likely to undergo an operation; the inferred average willingness to pay was $1.43 (SD 0.244). Surgery cost $6.13 to provide, including $0.86 for transportation to the village. DISCUSSION: Whether the value of trichiasis surgery exceeds the cost in The Gambia depends on how the value is measured. Individuals are willing to use only limited resources to obtain surgery even though lifetime economic productivity may increase substantially. All three economic measures can be used to inform policy.

Azithromycin for the treatment and control of trachoma.

Trachoma, a recurrent follicular conjunctivitis caused by Chlamydia trachomatis, is the leading cause of preventable blindness worldwide. Efforts to control this disease have met with limited success. This failure is due in part to the limitations of conventional antibiotic treatment, a prolonged course of topical tetracycline. Azithromycin, an azalide antibiotic, is effective against chlamydial infections when given as a single oral dose. Recent research from Africa has shown azithromycin to be as effective as tetracycline in the treatment of trachoma. Under operational conditions azithromycin proved to be more effective. This success is attributed to a much-improved compliance with treatment. Community-wide mass treatment with azithromycin is advocated as a means of controlling trachoma in endemic countries. Questions still remain over the use of azithromycin for this purpose. The frequency and target population of mass distribution campaigns need to be defined. A few countries are beneficiaries of a philanthropic donation by the manufacturer of azithromycin, Pfizer Inc. However, in the absence of a drug donation programme the cost-effectiveness of this measure is unclear.

Autologous blood transfusion. Current trends, nursing implications.

Developing a quality perioperative autologous blood recovery program is a team effort. Members of transfusion committees, hospital blood bank personnel, OR staff members, and the members of the surgery committee are all possible sources of information. Your local blood center also may have literature or services that could be of assistance. Knowledge of current autologous transfusion alternatives will help nurses communicate with patients regarding transfusion therapy and will make nurses more valuable participants in the crucial decisions necessary to deliver optimal patient care in the perioperative period.

Combined cataract and trabeculectomy surgery for advanced glaucoma in East Africa; visual and intra-ocular pressure outcomes.

AIM: To investigate visual and intra-ocular pressure (IOP) outcomes of combined cataract and glaucoma surgery at a high-volume centre in East Africa carried out over a 1-year period (2006). METHODS: A retrospective analysis of patient records. RESULTS: A total of 163 patients were identified. Mean age was 67 years (SD 11, range 21-86 years) and 113 (69%) were men. Presenting visual acuity in the operated eye was 6/60 or worse in 135/163 (93%) and was <3/60 in 76 of 163 (47%) patients. Mean presenting IOP was 28 mm Hg (SD 9, range 12-60). Pre-operative cup disc ratios were 0.8 or worse in 131 of 163 (85%) patients. Phacotrabeculectomy (PT) was carried out in 130 (80%) cases, small incision cataract surgery trabeculectomy (SICST) in 10 (6.1%) cases, and extra-capsular cataract extraction trabeculectomy (ECCET) in 23 (14.1%) cases. In all, 107 (66%) attended for follow-up (mean interval 104 days, range: 6-390 years, SD 88) and at follow-up 75 (70%) patients had improved visual acuity pre-operatively. Pre-operative cup disc ratio of 0.9 or greater predicted failure to improve VA at follow-up (OR 4.0 95% confidence interval (CI) 1.30-12.1). Fifty-nine (62% (95%CI 52-71%)) patients had follow-up IOPs of 6-15 mm Hg and 82 (85% (95% CI 78-92%)) had follow-up IOPs of 6-20 mm Hg. CONCLUSION: Combined surgery produces visual benefit for most patients with similar pressure control to pure trabeculectomy and is therefore a useful option in practises where follow-up may be doubtful.

Optic neuropathy endemic in secondary school children in Dar es Salaam, Tanzania.

AIM: To investigate the prevalence and causes of optic neuropathy, reported as epidemic in 1997, among secondary school students in Dar es Salaam, Tanzania. PATIENTS AND METHODS: First year students (n = 10,892) from 63 secondary schools located within 30 km from the base hospital were interviewed and had a visual acuity (VA) screening test. Students failing the 6/12-line in either eye were defined as having "poor eyesight" and referred to the base hospital where an optometrist re-tested VA and refracted them. An ophthalmologist examined students with VA of 6/12 or worse in either eye and visual impairment was defined as VA of worse than 6/12 with best correction. Associations between optic neuropathy, socioeconomic status and educational results were investigated. RESULTS: Students' ages ranged from 12 to 22 (mean 15.2) years; 50.6% were male. The prevalence of optic neuropathy was 0.3 (SD 0.051)%. The condition affected older students and was associated with the family having fewer economic possessions (car, computer, television). Optic neuropathy accounted for 19/33 (58%) of bilateral visual impairment cases. No effect of the disease on educational performance was identified. CONCLUSION: Optic neuropathy remains a significant problem in this population and can now be termed endemic rather than epidemic. Further research into its causes is required.