BMC Ophthalmology - Latest articles

Treatment of Branch Retinal Vein Occlusion induced Macular Edema with Bevacizumab

2008-09-29

Background: Branch retinal vein occlusion is a frequent cause of visual loss with currently insufficient treatment options. We evaluate the effect of Bevacizumab (Avastin(R)) treatment in patients with macular edema induced by branch retinal vein occlusion. Methods: Retrospective analysis of 32 eyes in 32 patients with fluorescein angiography proven branch retinal vein occlusion, macular edema and Bevacizumab treatment. Outcome measures were best corrected visual acuity in logMAR and central retinal thickness in OCT. Results: Visual acuity was significantly better 4 to 6 weeks after Bevacizumab treatment compared to visual acuity prior to treatment (before 0.7+/-0.3 and after 0.5+/-0.3; mean +/- standard deviation; p < 0.01, paired t-test). Gain in visual acuity was accompanied by a significant decrease in retinal thickness (454+/-117 to 305+/-129 um, p < 0.01, paired t-test). Follow up (170, 27 - 418 days; median, range) shows that improvement for both visual acuity and retinal thickness last for several months after Bevacizumab use. Conclusions: We present evidence that intravitreal Bevacizumab is an effective and lasting treatment for macular edema after branch retinal vein occlusion.

The Nigerian national blindness and visual impairment survey: rationale, objectives and detailed methodology

2008-09-22

Background: Despite having the largest population in Africa, Nigeria has no accurate population based data to plan and evaluate eye care services. A national survey was undertaken to estimate the prevalence and determine the major causes of blindness and low vision. This paper presents the detailed methodology used during the survey. Methods: A nationally representative sample of persons aged 40 years and above was selected. Children aged 10-15 years and individuals aged <10 or 16-39 years with visual impairment were also included if they lived in households with an eligible adult. All participants had their height, weight, and blood pressure measured followed by assessment of presenting visual acuity, refractokeratomery, A-scan ultrasonography, visual fields and best corrected visual acuity. Anterior and posterior segments of each eye were examined with a torch and direct ophthalmoscope. Participants with visual acuity of <=6/12 in one or both eyes underwent detailed examination including applanation tonometry, dilated slit lamp biomicroscopy, lens grading and fundus photography. All those who had undergone cataract surgery were refracted and best corrected vision recorded. Causes of visual impairment by eye and for the individual were determined using a clinical algorithm recommended by the World Health Organization. In addition, 1 in 7 adults also underwent a complete work up as described for those with vision <=6/12 for constructing a normative data base for Nigerians.DiscussionThe field work for the study was completed in 30 months over the period 2005-2007 and covered 305 clusters across the entire country. Concurrently persons 40+ years were examined to form a normative data base. Analysis of the data is currently underway. Conclusion: The methodology used was robust and adequate to provide estimates on the prevalence and causes of blindness in Nigeria. The survey would also provide information on barriers to accessing services, quality of life of visually impaired individuals and also provide normative data for Nigerian eyes.

Hospital admissions in older people with visual impairment in Britain

Jennifer R Evans, Liam Smeeth and Astrid E Fletcher — 2008-09-11

Background: We aimed to assess the risk of hospital admission associated with visual impairment in a representative sample of older people living in the community in Britain. Methods: Design: Prospective study of hospital admission in a population-based sample of community dwelling people aged 75 years and above in Britain. Setting: 53 general practices. Participants: 14,394 participants in the MRC Trial of Assessment and Management of Older people in the Community. Main outcome measure: Hospital admission. Results: Visually impaired older people had 238.7 admissions/1000 person-years compared to 169.7 admissions/1000 person-years in people with good vision: age and sex adjusted rate ratio (RR) 1.32 (95% CI 1.19 to 1.47). Adjusting for a wide range of potential explanatory factors largely eliminated this association: RR 1.06 (95% CI 0.94 to 1.20). However, adjusting for a more limited range of confounding factors, excluding those factors possibly a consequence of reduced vision, left a modest increased risk: RR 1.19 (95% CI 1.06 to 1.34). Conclusions: The association between visual impairment and rate of hospital admission can be attributed to higher levels of co-morbidity and reduced functional ability among people with reduced vision. Visual impairment is likely to be an important contributor to reduced functional ability, but other factors may also be involved.

The ChromaTest, a digital color contrast sensitivity analyzer, for diabetic maculopathy: a pilot study

2008-08-17

Background: To assess the ability of the Chromatest in investigating diabetic maculopathy.MethodPatients with Type 2 diabetes and no concurrent ocular pathology or previous laser photocoagulation were recruited. Visual acuities were assessed followed by colour contrast sensitivity testing of each eye using Chromatest. Dilated fundoscopy with slit lamp biomicroscopy with 78 D lens was then performed to confirm the stage of diabetic retinopathy according to the Early Treatment Diabetic Retinopathy Study. Results: 150 eyes in 150 patients were recruited into this study. 35 eyes with no previous laser photocoagulation were shown to have clinically significant macular oedema (CSMO) and 115 eyes with untreated non-proliferative diabetic retinopathy (NPDR) on fundus biomicroscopy. Statistical significant difference was found between CSMO and NPDR eyes for protan colour contrast threshold (p = 0.01). Statistical significance was found between CSMO and NPDR eyes for tritan colour contrast threshold (p = 0.0002). Sensitivity and specificity for screening of CSMO using pass-fail criterion for age matched TCCT results achieved 71% (95% confidence interval: 53–85%) and 70% (95% confidence interval: 60–78%), respectively. However, threshold levels were derived using the same data set for both training and testing the effectiveness since this was the first study of NPDR using the Chromatest Conclusion: The ChromaTest is a simple, cheap, easy to use, and quick test for colour contrast sensitivity. This study did not achieve results to justify use of the Chromatest for screening, but it reinforced the changes seen in tritan colour vision in diabetic retinopathy.

Tono-Pen XL tonometry during application of a suction ring in rabbits

2008-07-30

Background: The purpose of this study is to evaluate the use of Tono-Pen XL in measuring IOP during the application of a suction ring in rabbit eyes with manometrically controlled IOP. Methods: Tono-Pen XL was calibrated against direct manometry in 10 rabbit eyes. A suction ring was then applied in 4 rabbit eyes and the IOP was determined manometrically during suction ring application at 350 mmHg vacuum pressure. Finally, in 6 catheterized rabbit eyes the IOP was measured with Tono-Pen XL during suction ring application at suction vacuum from 350 to 650 mmHg, while keeping actual IOP stable at 30 mmHg and 60 mmHg. Results: Linear regression analysis revealed that the Tono-pen XL was reliable for IOPs between 10 and 70 mmHg (R2 = 0.9855). Direct manometry during suction ring application showed no statistically significant variation of Tono-Pen XL readings when the incanulation manometry intraocular pressure changed from 30 mmHg to 60 mmHg and no statistically significant correlation between suction vacuum and IOP measurements. Conclusion: Tono-Pen XL measurements are unreliable during the application of a suction ring on living rabbit eyes even when the actual IOP is forced to be within the validated range of Tono-Pen XL measurements. This inaccuracy is probably related to altered corneal and scleral geometry and stress.

Assessment of stereoscopic optic disc images using an autostereoscopic screen – experimental study

2008-07-23

Background: Stereoscopic assessment of the optic disc morphology is an important part of the care of patients with glaucoma. The aim of this study was to assess stereoviewing of stereoscopic optic disc images using an example of the new technology of autostereoscopic screens compared to the liquid shutter goggles. Methods: Independent assessment of glaucomatous disc characteristics and measurement of optic disc and cup parameters whilst using either an autostereoscopic screen or liquid crystal shutter goggles synchronized with a view switching display. The main outcome measures were inter-modality agreements between the two used modalities as evaluated by the weighted kappa test and Bland Altman plots. Results: Inter-modality agreement for measuring optic disc parameters was good [Average kappa coefficient for vertical Cup/Disc ratio was 0.78 (95% CI 0.62–0.91) and 0.81 (95% CI 0.6–0.92) for observer 1 and 2 respectively]. Agreement between modalities for assessing optic disc characteristics for glaucoma on a five-point scale was very good with a kappa value of 0.97. Conclusion: This study compared two different methods of stereo viewing. The results of assessment of the different optic disc and cup parameters were comparable using an example of the newly developing autostereoscopic display technologies as compared to the shutter goggles system used. The Inter-modality agreement was high. This new technology carries potential clinical usability benefits in different areas of ophthalmic practice.

Modelling lifetime cost consequences of ReSTOR® in cataract surgery in four European countries

Antoine Lafuma and Gilles Berdeaux — 2008-07-15

Background: To compare the lifetime costs of liberating patients from spectacles after cataract surgery by implanting the multifocal intraocular lens (IOL) 'ReSTOR®' versus monofocal IOLs in France, Italy, Germany and Spain. Methods: A Markov model was created to follow patient cohorts from cataract surgery until death. Prevalence rates of patients not needing spectacles after cataract surgery were obtained from clinical trials. Resource utilisation included implant surgery, IOLs, spectacles, visits to ophthalmologists and eye centres, transport, and time lost by patients. Economic perspectives were those of Society and Sickness Funds (SFs). Results: The mean number of spectacles purchased after ReSTOR® was 1.34–1.61 and after monofocal IOLs 6.05–7.27. From the societal perspective, total cost estimates discounted by 3% were between €3,551 and €4,052 with ReSTOR® compared to €3,989 and €5,548 with monofocal IOLs. Undiscounted savings related to ReSTOR® ranged from €815 to €2,164. From the SFs' perspective total cost estimates discounted by 3% were between €2,150 and €2,524 with ReSTOR® compared to €2,324 and €2,610 with monofocal IOLs. Savings related to ReSTOR®, once costs discounted, ranged from €61 to €219. Discount and spectacle freedom prevalence rates were the most sensitive parameters. Conclusion: The bulk of the savings related to ReSTOR® were realized outside the SF. From both a societal and SF perspective, savings, after a 3% discounting, achieved by liberating patients from spectacles counterbalanced the initially higher cost of ReSTOR®. ReSTOR® is a cost saving alternative to spectacles for patients requiring cataract surgery.

Comparative study of the stability of bimatoprost 0.03% and latanoprost 0.005%: A patient-use study

Mauricio D Paolera, Niro Kasahara, Cristiano C Umbelino and John G Walt — 2008-06-11

Background: The stability of ophthalmic preparations in multidose containers is influenced by the preservative as well as the stability of the active ingredient. Unstable drugs may require refrigeration to preserve their active ingredient level and they are more likely to degrade over time, therefore becoming more susceptible to degradation based on patient mishandling. The purpose of this study was to determine the degree of molecular degradation that occurs in bimatoprost and latanoprost in a patient-use setting. Methods: This was an open-label, laboratory evaluation of the relative stability of bimatoprost and latanoprost. Patients presently using bimatoprost (n = 31) or latanoprost (n = 34) were identified at 2 clinical sites in Brazil. Patients were instructed to use and store their drops as usual and return all used medication bottles between day 28 and day 34 after opening. Results: Bimatoprost demonstrated no degradation, but latanoprost degraded at various levels. The mean age of bimatoprost was 43.0 ± 3.4 days and the mean age of latanoprost was 43.9 ± 2.8 days (P = .072). The mean percentage of labeled concentration was 103.7% in the bimatoprost bottles and 88.1% in the latanoprost bottles (P < 001). Conclusion: This study showed that bimatoprost maintained ≥100% concentration throughout the study period while latanoprost did not.

Prevalence of dry eye syndrome and diabetic retinopathy in type 2 diabetic patients

2008-06-02

Background: This study was performed to assess the prevalence of dry eye syndrome and diabetic retinopathy (DR) in type 2 diabetic patients and their contributing factors. Methods: 199 type 2 diabetic patients referred to Yazd Diabetes Research Center were consecutively selected. All Subjects were assessed by questionnaire about other diseases and drugs. Dry eye syndrome was assessed with Tear break up time tests and Schirmer. All the subjects underwent indirect ophthalmoscopy and retinal color photography. DR was graded according to early Treatment Diabetic Retinopathy (ETDRS) criteria. Results: Of 199 subjects, 108 patients (54.3%) suffer from dry eye syndrome. Although dry eye syndrome was more common in older and female patients, this association was not significant. But there was significantly association between dry eye syndrome and duration of diabetes (P = 0.01). Dry eye syndrome was more frequent in diabetic patients with DR (P = 0.02). DR was found in 140 patients (70.35%), which included 34 patients (17.1%) with mild non proliferative DR (NPDR), 34 patients (17.1%) with moderate NPDR, 22 patients (11.1%) with severe NPDR and 25 patients (25.1%) with proliferative DR (PDR). There were significant relation between age, sex and duration of diabetes and DR. Conclusion: In this study the prevalence of dry eye syndrome was 54.3%. Diabetes and dry eyes appear to have a common association. Further studies need to be undertaken to establish an etiologic relationship. However, examination for dry eye should be an integral part of the assessment of diabetic eye disease.

Effectiveness of mobile-phone short message service (SMS) reminders for ophthalmology outpatient appointments: Observational study

Elizabeth Koshy, Josip Car and Azeem Majeed — 2008-05-31

Background: Non-attendance for hospital outpatient appointments is a significant problem in many countries. It causes suboptimal use of clinical and administrative staff and financial losses, as well as longer waiting times. The use of Short Message Service (SMS) appointment reminders potentially offers a cost-effective and time-efficient strategy to decrease non-attendance and so improve the efficiency of outpatient healthcare delivery. Methods: An SMS text message was sent to patients with scheduled appointments between April and September 2006 in a hospital ophthalmology department in London, reminding them of their appointments. This group acted as the intervention group. Controls were patients with scheduled ophthalmology appointments who did not receive an SMS or any alternative reminder. Results: During the period of the study, 11.2% (50/447) of patients who received an SMS appointment reminder were non-attenders, compared to 18.1% (1720/9512) who did not receive an SMS reminder. Non-attendance rates were 38% lower in patients who received an SMS reminder than in patients who did not receive a reminder (RR of non-attendance = 0.62; 95% CI = 0.48 – 0.80). Conclusion: The use of SMS reminders for ophthalmology outpatient appointments was associated with a reduction of 38% in the likelihood of patients not attending their appointments, compared to no appointment reminder. The use of SMS reminders may also be more cost-effective than traditional appointment reminders and require less labour. These findings should be confirmed with a more rigorous study design before a wider roll-out.