Search

By allowing the surgeon to measure and modify corneal curvature during wound closure, intraoperative keratometry can reduce postoperative astigmatic errors. A number of keratometric devices have been developed over the last 10 years, each offering a compromise between cost, accuracy and ease of use. The Barrett keratoscope is a simple, inexpensive hand-held device which gives a qualitative indication of the degree of astigmatism. Addition of a transparent overlay, as described in this paper, sets the distance at which the keratoscope is held and allows the magnitude of the astigmatism to be determined, thereby enabling refined adjustment of the suture tension during wound closure. We describe the error in estimation of astigmatism due to the effect of the distance at which the keratoscope is held from the cornea. [ABSTRACT FROM AUTHOR]

Background/aim: Over the period of 19 years to 1999, cataract surgery numbers increased 6% per annum in Western Australia (WA), promoted by the convenience, efficacy, and general safety of outpatient phacoemulsification surgery. Although endophthalmitis is an uncommon complication, it is a major cause of post-cataract surgery blindness. The present population study investigates not only the prevalence of endophthalmitis but provides an accurate incidence of endophthalmitis in WA over the same period. Methods: Using the hospital morbidity data system (HMDS) of the WA Record Linkage Project, and cross validating against three independent databases (anaesthetic and microbiological databases and surgeons' logbooks) the authors examined 698 case notes that were potentially cases of endophthalmitis for the period 1980 to June 1999. As the database linkage was incomplete for 1999, only the 188 confirmed cases to 1998 were included in the present study. Additional case note validation was performed to confirm the correct codes for the cataract surgical procedure. Results: Despite changes in surgical technique and prophylaxis over the study period of 19 years, the incidence of endophthalmitis remained largely unchanged, averaging one in 500 surgical cases overall. However, the incidence fluctuated over time and varied with the location of surgery ranging from 0.65 per 1000 operations to 16.4 per 1000 operations. Conclusion: These data highlight previously undescribed temporal and geographic variations in the incidence of endophthalmitis. It is uncertain whether the wide variation in prophylactic practices throughout the ophthalmic community has any bearing on the incidence of endophthalmitis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although intravitreal high dose ganciclovir has previously been found to provide excellent control of cytomegalovirus (CMV) retinitis, little was known about the vitreous concentrations of ganciclovir after a 2 mg intravitreal injection. METHODS: Eleven vitreous samples were taken from seven patients with CMV retinitis at 24 and 72 hours after a 2 mg intravitreal injection of ganciclovir and the concentration of ganciclovir was measured by high performance liquid chromatography. RESULTS: The mean concentration of ganciclovir at 24 hours was 143.8 mg/l (95% confidence interval 97.8-190) and at 72 hours was 23.4 mg/l (95% CI 0-49.7). The half life ranged from 11.9 to 26.3 (mean 18.8) hours in the four patients who had two samples taken. The mean half life calculated from the mean concentrations at 24 and 72 hours was 18.3 hours, so the calculated mean concentration at 7 days was 0.6 mg/l. CONCLUSIONS: This suggests that it takes about 7 days to eliminate the intravitreal ganciclovir, and that it is not likely to accumulate with weekly injections. The intravitreal concentrations achieved with high dose therapy remained above the ID50 for CMV (0.25-1.22 mg/l) for up to 7 days. [ABSTRACT FROM PUBLISHER]

BACKGROUND--It was previously found that high dose intravitreal ganciclovir provided superior treatment of cytomegalovirus retinitis compared with intravenous treatment. This study examined the stability and solubility of the ganciclovir solution to determine the shelf life of prepared solution, and compared the cost of intravitreal with intravenous therapy. METHODS--For the solubility studies high performance liquid chromatography was used to determine the ganciclovir concentration in various solutions. Measurements were taken of freshly made 20 mg/ml solution, the same solution stored at room temperature or frozen for 10, 17, and 24 days, after the solution was filtered, and after it was heated at 56 degrees C. For the cost comparison analysis the cost of 22 patients treated exclusively with intravitreal high dose ganciclovir was compared with cost estimates for the same patients treated with a standard intravenous therapy regimen over the same time. RESULTS--There was little variation in the concentration of ganciclovir regardless of the storage conditions, suggesting that the 20 mg/ml solution was very stable. The heating and filtering experiments suggest that maximum solubility was achieved both in the freshly prepared and thawed frozen stored solution. The total cost of the intravitreal treatment was Aus $172,435 and the estimate of intravenous treatment was Aus $490,521. This represents a total saving of $318,086 (65%), or $14,458 per patient. The average number of weeks of treatment for each patient was 27.9 (613 weeks/22 patients), so the saving per patient per year was $29,946. CONCLUSION--High dose intravitreal ganciclovir therapy may be administered in a very cost effective way, which along with its acceptability, safety, and clinical efficacy make it an attractive method of treatment of CMV retinitis. [ABSTRACT FROM PUBLISHER]

A letter to the editor is presented in response to the article which investigates cataract surgery outcomes by JB Semmens in the February 23, 2007 issue.

The intraocular pressure change produced by an intravitreal injection of ganciclovir, 2 mg in 0.1 ml, was studied in patients with cytomegalovirus retinitis. Using a Tono-pen XL to measure the intraocular pressure (IOP) of four patients (six eyes) we found the mean pressure immediately following injection was 44.5 mm Hg. Measurements taken on separate occasions after a 30 mm Hg decompression of the eye for 15 minutes before the injection showed a mean IOP of only 20.6 mm Hg after the injection. Mercury bag decompression of the eye significantly reduced the rise in IOP following intravitreal injection (difference in the mean IOP rise = 26.4 mm Hg, df = 54, t = 7.67, p < 0.001). Without ocular decompression before injection, all patients complained of temporary loss of vision, and reflux of the injection solution was frequently observed. Use of ocular decompression also reduced the discomfort of the injection. Throughout the full course of treatment by this means there were no adverse effects on the visual acuity. This technique is recommended to those performing intravitreal injections. [ABSTRACT FROM PUBLISHER]

Replies to a critique of an article titled 'Astigmatism and the analysis of its surgical correction,' by the authors. Concepts that conflict with those of the authors' but which do not diminish the value of vector analysis as a process measure.