Biomedical subjects

Darwin C Minassian

Publications and source records attributed to Darwin C Minassian.

3 recordsLinked to original sources

PubMed2004

Effect of cataract surgery on the corneal endothelium: modern phacoemulsification compared with extracapsular cataract surgery.

PURPOSE: To investigate whether modern phacoemulsification surgery results in more damage to the corneal endothelium than extracapsular cataract extraction (ECCE), and to examine which preoperative, operative, and postoperative factors influence the effect of cataract surgery on the endothelium. DESIGN: Randomized controlled trial. PARTICIPANTS: Five hundred patients 40 years or older were randomized into 2 groups (ECCE, 249; phacoemulsification, 251). METHODS: Central corneal endothelial cell counts, coefficient of variation of cell size, and hexagonality were assessed before surgery and up to 1 year postoperatively. MAIN OUTCOME MEASURE: Endothelial cell count. RESULTS: Four hundred thirty-three patients completed the trial. The initial preoperative mean cell count for the entire sample was 2481 (standard error [SE]: 18.6), reduced at 1 year postoperatively to 2239 (SE: 23.5). An average 10% reduction in cell count was recorded by 1 year postoperatively. There was no such change in hexagonality or in the coefficient of variation. There was no significant difference in overall percentage cell loss between the 2 treatment groups. Factors associated with excessive cell loss (> or =15% by 1 year) were a hard cataract (odds ratio [OR]: 2.1, 95% confidence limits: 1.1-4.1; P = 0.036), age (OR: 1.04, P = 0.005), and capsule or vitreous loss at surgery (OR: 2.38, P = 0.106). Phacoemulsification carried a significantly higher risk (OR: 3.7, P = 0.045) of severe cell loss in the 45 patients with hard cataracts relative to ECCE (52.6% vs. 23.1%; chi-square test, P = 0.041), with both procedures achieving similar postoperative visual acuity outcomes. CONCLUSIONS: No significant difference in overall corneal endothelial cell loss was found between these 2 operative techniques. The increased risk of severe cell loss with phacoemulsification in patients with hard cataracts suggests that phacoemulsification may not be the optimal procedure in these cases, and that ECCE should be preferred.

Adult↗

PubMed2003

Retinal detachment in cytomegalovirus retinitis: intravenous versus intravitreal therapy.

PURPOSE: To compare the rate of retinal detachment in a group of patients treated with intravitreal ganciclovir to the rate of retinal detachment in a group of patients treated with systemic ganciclovir. METHODS: A retrospective non-randomized comparative case series was conducted. The participants were 186 consecutive patients with cytomegalovirus (CMV) retinitis treated at two centres over the period from June 1990 to May 1997. Of the 186, 133 patients had systemic therapy of whom 113 had intravenous ganciclovir or foscarnet and 20 had oral ganciclovir, and 53 patients had intravitreal induction and maintenance therapy. The main outcome measure was the rate of retinal detachment, which was calculated using person-months-at-risk denominators. The effect measure used in the main comparative analysis was the hazard ratio obtained from multiple regression using the Cox proportional hazards model. RESULTS: Retinal detachment occurred in three of 53 patients in the intravitreal therapy group, one of 20 patients receiving oral maintenance therapy and 21 of 113 patients receiving intravenous maintenance therapy. The risk of retinal detachment with systemic therapy was 14-fold higher than with intravitreal therapy (P < 0.001)and up to fourfold higher with oral maintenance therapy. CONCLUSIONS: Intravitreal therapy offers a significant advantage over systemic therapy in the treatment of CMV retinitis by substantially reducing the risk of CMV-related retinal detachment.

AIDS-Related Opportunistic Infections↗

PubMed2002

Refractive error and visual outcome after cataract extraction.

PURPOSE: To determine the range of biometry prediction error of the postoperative refraction and the visual outcome after cataract surgery. SETTING: Postgraduate teaching hospital. METHODS: Refraction and visual outcomes were recorded prospectively for a consecutive case series of 1817 cataract procedures. Complete preoperative and postoperative data were available for 1676 eyes (92.4%). The paired mean error of the difference between the predicted and achieved refraction, the percentages falling within +/-0.50 diopter (D), +/-1.00 D, and +/-2.00 D, and the values that contained 99% of data points were then calculated. The number that achieved a final Snellen visual acuity of 6/12 was determined in all eyes and in eyes without preoperative ocular comorbidity. This analysis was repeated in 1265 eyes that received a single intraocular lens (IOL) design (C10UB/C11UB) after phacoemulsification through a clear corneal incision. RESULTS: The paired mean error of the difference between the predicted and achieved postoperative refraction in all eyes was -0.32 D +/- 1.05 (SD); 72.3% of eyes were within +/-1.00 D of the planned refraction, with bounds of 99% of observation of +2.92 D and -3.98 D. In the single IOL group, the paired mean error was -0.32 +/- 0.94 D; 74.2% of eyes fell within +/-1.00 D of the planned refraction, with bounds of 99% of observation of +2.54 D and -3.81 D. Axial length did not determine the magnitude of the biometry prediction error. At discharge from the service, 86.9% of all eyes and 95.4% of eyes without preoperative ocular comorbidity achieved a final corrected Snellen acuity of 6/12. CONCLUSION: These data provide benchmark information that can be used to monitor clinical practice.

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