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The Value of Ultrasound in Intraocular Lens Power Calculation
VOL. 86, NO. 5
MEETINGS, CONFERENCES, SYMPOSIA
The reliability of the specular microscope counts was then tested by comparing cell counts, using the specular microscope to estimate cell counts of stained histological endothelial specimens. The 20-power objective was believed to be the most practical magnification to use in estimating endothelial cell counts. One field (area = 0.015 mm 2 ) was sufficient to give reliable counts in the normal rabbit endothelium when central and peripheral cell counts were compared (P <.05). A difference of approximately 10% was found between central and peripheral en dothelial cell counts with more cells being central. A reasonable correlation (P <.05) between histologic specimen counts and specular photomicrography counts was found. This suggests that the specular microscope is a reliable indica tor of endothelial cell densities. T H E VALUE O F ULTRASOUND I N INTRAOCULAR LENS P O W E R CALCULATION
E. M. T. Moniz and M. S. Kazdan The value of ultrasonography in the calculation of intraocular lens power be fore implantation was studied in 21 eyes of patients who underwent primary im plantation. The observed postoperative refraction was compared with the calcu lated for a standard 18.50-diopter lens. For the calculated lens power (with addi tion of +1.00 diopter) 48% were <1.50 diopters; 85% <3.00 diopters; 95% <4.50 diopters; and only 5% of the errors were >6.00 diopters. Refractive errors calculat ed for a standard 18.50 lens did not differ significantly from the above values; 62% were <1.50 diopters; 90% <3.00 diopters; and no errors were >6.00 diopters. It appeared that one can achieve similar results with either an 18.50-diopter stan dard lens or by calculating the power by ultrasound.
721
ELECTRORETINOGRAMS IN Z I N C - D E F I C I E N T RATS
M. Motolko, A. V. Rao, Y. Matuk, and J. Parker The effects of dietary zinc deficiency on the electroretinograms of adult male rats and pups nursed by zinc-deficient moth ers were examined. In one experiment, six 80-day-old rats were given a zincdeficient diet. A second group of six rats served as pair-fed controls. At the end of a five-month period, the zinc-deficient group showed growth retardation, fluctu ating patterns of food intake, and hair changes. These zinc-deficient adults showed significantly lower levels of zinc in feces and hair as well as histologic signs of testicular atrophy. Liver and reti na zinc levels and electroretinograms re mained comparable to controls. In anoth er experiment, pups nursed for 21 days by a zinc-deficient mother were examined. These animals had significantly lower weights, depressed electroretinograms, and lower total body zinc levels than control groups. The existence of stable and labile pools of zinc were postulated. Some tissues such as hair and testicles were more sen sitive to zinc deficiency, whereas liver and retina were less easily depleted. The effects of zinc deficiency on electroretino grams might be caused by decreased vita min A levels or decreased opsin synthesis reflecting the decreased protein synthesis of zinc deficiency. WOUND HEALING OF TRABECULECTOMIES IN RABBITS
A. Seetner and J. D. Morin The wound healing of trabeculectomies in rabbit eyes was observed with photo graphs, fluorescein filtration, and histo logic sections. Initially all except one animal developed blebs and had proven
MEETINGS, CONFERENCES, SYMPOSIA
The reliability of the specular microscope counts was then tested by comparing cell counts, using the specular microscope to estimate cell counts of stained histological endothelial specimens. The 20-power objective was believed to be the most practical magnification to use in estimating endothelial cell counts. One field (area = 0.015 mm 2 ) was sufficient to give reliable counts in the normal rabbit endothelium when central and peripheral cell counts were compared (P <.05). A difference of approximately 10% was found between central and peripheral en dothelial cell counts with more cells being central. A reasonable correlation (P <.05) between histologic specimen counts and specular photomicrography counts was found. This suggests that the specular microscope is a reliable indica tor of endothelial cell densities. T H E VALUE O F ULTRASOUND I N INTRAOCULAR LENS P O W E R CALCULATION
E. M. T. Moniz and M. S. Kazdan The value of ultrasonography in the calculation of intraocular lens power be fore implantation was studied in 21 eyes of patients who underwent primary im plantation. The observed postoperative refraction was compared with the calcu lated for a standard 18.50-diopter lens. For the calculated lens power (with addi tion of +1.00 diopter) 48% were <1.50 diopters; 85% <3.00 diopters; 95% <4.50 diopters; and only 5% of the errors were >6.00 diopters. Refractive errors calculat ed for a standard 18.50 lens did not differ significantly from the above values; 62% were <1.50 diopters; 90% <3.00 diopters; and no errors were >6.00 diopters. It appeared that one can achieve similar results with either an 18.50-diopter stan dard lens or by calculating the power by ultrasound.
721
ELECTRORETINOGRAMS IN Z I N C - D E F I C I E N T RATS
M. Motolko, A. V. Rao, Y. Matuk, and J. Parker The effects of dietary zinc deficiency on the electroretinograms of adult male rats and pups nursed by zinc-deficient moth ers were examined. In one experiment, six 80-day-old rats were given a zincdeficient diet. A second group of six rats served as pair-fed controls. At the end of a five-month period, the zinc-deficient group showed growth retardation, fluctu ating patterns of food intake, and hair changes. These zinc-deficient adults showed significantly lower levels of zinc in feces and hair as well as histologic signs of testicular atrophy. Liver and reti na zinc levels and electroretinograms re mained comparable to controls. In anoth er experiment, pups nursed for 21 days by a zinc-deficient mother were examined. These animals had significantly lower weights, depressed electroretinograms, and lower total body zinc levels than control groups. The existence of stable and labile pools of zinc were postulated. Some tissues such as hair and testicles were more sen sitive to zinc deficiency, whereas liver and retina were less easily depleted. The effects of zinc deficiency on electroretino grams might be caused by decreased vita min A levels or decreased opsin synthesis reflecting the decreased protein synthesis of zinc deficiency. WOUND HEALING OF TRABECULECTOMIES IN RABBITS
A. Seetner and J. D. Morin The wound healing of trabeculectomies in rabbit eyes was observed with photo graphs, fluorescein filtration, and histo logic sections. Initially all except one animal developed blebs and had proven