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Biomedical subjects

G Brian

Publications and source records attributed to G Brian.

At least 19 recordsLinked to original sources

Cataract blindness--challenges for the 21st century.

Cataract prevalence increases with age. As the world's population ages, cataract-induced visual dysfunction and blindness is on the increase. This is a significant global problem. The challenges are to prevent or delay cataract formation, and treat that which does occur. Genetic and environmental factors contribute to cataract formation. However, reducing ocular exposure to UV-B radiation and stopping smoking are the only interventions that can reduce factors that affect the risk of cataract. The cure for cataract is surgery, but this is not equally available to all, and the surgery which is available does not produce equal outcomes. Readily available surgical services capable of delivering good vision rehabilitation must be acceptable and accessible to all in need, no matter what their circumstances. To establish and sustain these services requires comprehensive strategies that go beyond a narrow focus on surgical technique. There must be changes in government priorities, population education, and an integrated approach to surgical and management training. This approach must include supply of start-up capital equipment, establishment of surgical audit, resupply of consumables, and cost-recovery mechanisms. Considerable innovation is required. Nowhere is this more evident than in the pursuit of secure funding for ongoing services.

Age Factors↗

Evaluation of the quality of generic polymethylmethacrylate intraocular lenses marketed in India.

PURPOSE: To determine the quality of single-piece, allpolymethylmethacrylate (PMMA) Intraocular lenses (IOLs) from eght generic manufacturers marketing their product in India. This assessment of quality was made with respect to compliance with internationa standards for the manufacture of IOLs, specifically those parameters most likely to affect patient postoperat ve visual acuity and the long-term biocompatibility of the implanted lens. METHODS: Ten IOLs from each of eight manufacturers were purchased randomly from commercial retail outlets in India. Each IOL, in a masked fashion, had its physical dimensions, optical performance and cosmetic appearance assessed, using the methods prescribed in ISO 11979-2 and 11979-3. Validation of manufacturing process controls were determined by statistical process contro techniques. Four IOLs from each manufacturer were also tested for the presence of unpolymerized PMMA using gas chromatography. RESULTS: Only lenses from two IOL manufacturers complied with the optical and mechanical standards. All other manufacturers' lenses failed one or more of these tests. Intraocular lenses from only two producers met with surface quality and bulk homogeneity standards. All others exhibited defects such as surface contamination and scratches, poor polishing, and chipped or rough positioning holes. Lenses from two producers exhibited high levels of methylmethacrylate monomer (MMA). CONCLUSIONS: Non-clinical grade PMMA starting material may have been used in the manufacture of IOLs by some producers. Critical manufacturing defects occurred in the IOLs from five of the eight producers tested. Only one manufacturer's IOLs met all specifications, and on statistical analysis demonstrated good manufacturing process contro with respect to the properties tested. With the widespread acceptance of IOL implantation in developing countries, such as India, it is essential that in the rush to make this the norm, the quality of implants used not be overlooked.

Biocompatible Materials↗

An innovation in developing world cataract surgery: sutureless extracapsular cataract extraction with intraocular lens implantation.

PURPOSE: The benefits of sutureless cataract surgery have not been available to the majority of developing world patients. This report describes a surgical technique developed to gain the benefits of self-sealing sutureless techniques, without the need for costly, complex instrumentation, expensive consumables, or difficult nucleus fragmentation manoeuvres in the anterior chamber. METHOD: A detailed description of a sutureless technique that uses only standard manual extracapsular cataract extraction instrumentation is presented. The clinical records of 362 consecutive completed sutureless surgeries were reviewed, and preliminary indicative data of visual outcome for those having follow up between postoperative weeks 3 and 8 are also presented. RESULTS: Hospital and eye camp experience confirms this operation offers speed, routinely 5 min or less with mature cataracts, reduced cost because no suture, viscoelastic or anterior chamber maintainer is needed, wound security and stability, and rapid effective visual rehabilitation. Uncorrected distance visual acuity during the third to eighth postoperative week was available for 266 of the 362 patients (73%): 10, 145, 101, and 10 had acuities of better than 6/9, 6/9-6/18, 6/24-6/60, and worse than 6/60, respectively. Ninety-seven, 165, 12, and two of the 276 (76%) patients with recorded corrected distance acuity were in the same groups. Comparing postoperative with preoperative corneal astigmatism for each patient with postoperative information available (208), without regard to axis, the amplitude of astigmatism worsened by a mean of 0.94 dioptres (+/- 0.17, 95% confidence; +/- 1.23 standard deviation; 7.5D maximum worsening; 2.5D maximum improvement). No attempt has been made to analyse complication type or frequency in this preliminary report. CONCLUSION: The authors believe this sutureless cataract extraction technique to be an innovation with widespread application in the developing world. Further and more exhaustive critical appraisal is warranted.

Cataract Extraction↗

Modern surgery for global cataract blindness: preliminary considerations.

Unoperated cataract in the developing world remains ophthalmology's major unsolved problem. Recent developments have brought into question the assumptions of those who have thought that extracapsular surgery with implantation of a posterior chamber intraocular lens is an unrealistic approach to the treatment of global cataract blindness. High-quality 1-piece posterior chamber intraocular lenses are being manufactured locally for approximately $10 each. Most ophthalmologists can be trained to perform extracapsular surgery in a 1-month course. This process is particularly effective if outstanding local surgeons receive intensive training to become instructors. While the incidence and treatment of posterior capsule opacification requires further study, the development of a low-cost YAG laser may be a solution. Imaginative ways to recover costs will need to be developed if the staggering prevalence of cataract blindness is to be effectively addressed. The improved result of modern surgery may make patients more willing to pay for their operation.

Blindness↗

A case-control study of biometry in healthy and cataractous Eritrean eyes.

The keratometry and axial length readings of healthy eyes (405 subjects) and cataractous eyes (63 subjects) from a sample of Tigrinians living in the Eritrean capital of Asmara were obtained. All subjects were at least 40 years of age. The mean keratometry reading for healthy eyes was 43.37 diopters (SD +/- 1.61), while that for cataractous eyes was 43.57 diopters (SD +/- 1.79). These values were not significantly different. Similarly, there was no significant difference in the mean ocular axial length for the two groups (healthy eyes; 23.03 mm, SD +/- 1.24: cataractous eyes; 23.34 mm, SD +/- 1.54). There was no correlation between age and the biometry readings of healthy eyes. Data from this study has been used to calculate a standard intraocular lens power for use by Eritrea's Blindness Prevention Programme during cataract surgery on this population (22 diopters at A constant 118.3). With this intraocular lens, 48% of patients will be within +/- 1D of emmetropia when left without spectacle correction; 73% will need a spectacle correction within +/- 2D to produce emmetropia.

Biometry↗

Steroid-induced ocular hypertension in the presence of a functioning Molteno seton.

BACKGROUND: Steroid-induced ocular hypertension is generally attributed to alterations in the trabecular meshwork, reducing aqueous outflow. METHOD AND RESULTS: A case with several episodes of steroid-induced ocular hypertension is presented. Later, with unremitting intraocular pressures above 50 mmHg, despite maximal hypotensive medication, there is evidence of extensive failure of aqueous egress. A successful Molteno seton bypasses the failed trabecular meshwork to lower the pressure into the teens. The eye is then challenged with topical steroid on two occasions. The pressure rises, only to fall again with steroid withdrawal. CONCLUSION: Here is a case where the trabecular meshwork has been bypassed, but ocular hypertension was still induced with the application of topical steroid.

Adolescent↗

A "development aid" approach to Third World surgical blindness.

Establishing local production of intraocular lenses (IOLs) and sutures should be as much a part of surgical blindness prevention assistance to Third World countries as teaching extracapsular cataract extraction with IOL implantation, because it would increase financial independence and encourage economic growth.

Blindness↗

Basic ophthalmic assessment and care workshops for rural health workers.

The inequitable distribution of medical services in Australia means that many rural dwellers do not have easy access to ophthalmic care. In regions with no medical personnel, appropriately trained rural health workers may provide ophthalmic assessment, primary treatment, and, in some circumstances, definitive care. In areas with overburdened services, these rural health workers may augment facilities already established. In an attempt to improve the accessibility and quality of ophthalmic services available to presently disadvantaged rural inhabitants, the aims, curriculum, and structure of a 'Basic Ophthalmic Assessment and Care Workshop', for the transfer of knowledge and skills to such rural health workers, is presented.

Allied Health Personnel↗

On the practicalities of eye camp cataract extraction and intraocular lens implantation in Nepal.

Based on our experience in Nepal, we discuss the practicalities of performing extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation in the context of the third-world eye camp. At slightly less than 30 minutes per case, while not as quick as an intracapsular cataract extraction (ICCE) with a Graefe section, the trade-off between vision result and operation time, according to patients, is very much in favor of the ECCE/IOL technique. Also, although IOLs remain expensive, by using donated lenses, the overall costs of providing ECCE/IOL surgery need not exceed those of providing ICCE.

Cataract Extraction↗