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M J Cosentino

Publications and source records attributed to M J Cosentino.

At least 19 recordsLinked to original sources
PubMed2001

Corneal ectasia after laser in situ keratomileusis.

PURPOSE: To describe 7 patients who developed ectasia following laser in situ kerato-mileusis (LASIK). SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: In this retrospective study of 7 patients, visual acuity, refraction, pachymetry, and corneal topography were examined before and after the refractive procedure and the occurrence of ectasia. RESULTS: Two of the 7 patients required penetrating keratoplasty. Ectasia developed within a mean of 1.02 years +/- 0.31 (SD). The clinical evolution of ectasia and the potential physiopathogenic causes of ectasia are described. CONCLUSION: Ectasia should be considered a potential complication of LASIK that is closely related to corneal thickness, but another variable, the optical zone diameter, should also be considered.

Adult↗
PubMed2001

Customized ablation for asymmetrical corneal astigmatism.

PURPOSE: To evaluate laser in situ keratomileusis (LASIK) cases in which a customized ablation assisted by corneal topography was performed. SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: The study group comprised 23 cases with asymmetrical corneas; 17 had myopia and 6, hyperopia. Visual acuity, spherical equivalent (SE), and cylinder vectorial change measurements, along with keratometry and corneal topography, were performed in all cases preoperatively and postoperatively. RESULTS: In the myopic cases, the mean preoperative SE was -4.92 diopters (D) +/- 2.46 (SD); it was -0.38 +/- 0.66 D after a mean follow-up of 4.41 +/- 2.32 months. In the hyperopic cases, the preoperative SE was +3.54 +/- 1.57 D; it was +0.33 +/- 0.50 D after a mean follow-up of 3.42 +/- 3.23 months. Cylinder vectorial change, visual acuity, and the number of visual acuity lines gained or lost were also evaluated in both groups. CONCLUSION: Although some features of our algorithm for corneal-topography-assisted customized ablations should be modified, the results of our treatment of cases with asymmetrical astigmatism were encouraging.

Adult↗
PubMed2000

Contrast sensitivity assessment using the visual performance tester.

The visual performance tester (VPT), a device that uses patient response time as a variable to assess visual power, is described. Results in 126 emmetropic eyes that had not had surgery are presented. The VPT provides more complete and accurate information about visual performance than the standard visual acuity examination because the device considers all variables involved in visual function results.

Contrast Sensitivity↗
PubMed2000

Comparison of optical zones in hyperopic laser in situ keratomileusis: 5.9 mm versus smaller optical zones.

PURPOSE: To compare the results of hyperopic laser in situ keratomileusis (LASIK) with a 5.9 mm optical zone (OZ) with those with smaller zones (4.4 to 5.5 mm). SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: The results of LASIK with a 5.9 mm OZ (147 cases) were compared with those in a previously reported group treated with OZs of 4.4 to 5.5 mm (679 cases). In the 5.9 mm group, 31.3% (46 eyes) had low hyperopia, 46.9% (69 eyes) had moderate hyperopia, and 21.8% (32 eyes) had high hyperopia. In the smaller OZ group, follow-up was 1 month in 79.4% (539 eyes), 3 months in 75.5% (501 eyes), 6 months in 68.5% (465 eyes), and 1 year in 38.3% (260 eyes). The hyperopic population studied was divided into 3 subgroups based on the preoperative spherical equivalents of the manifest refraction: subgroup A, low hyperopia: < or = +2.0 diopters (D); subgroup B, moderate hyperopia: +2.0 to +3.0 D; and subgroup C, high hyperopia: > +3.0 D. The following parameters were measured postoperatively: uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction (evolution and distribution), and visual acuity lines gained and lost. RESULTS: The preoperative mean spherical equivalents in the 5.9 mm OZ group were +1.47 +/- 0.41 (SD) (subgroup A); +2.98 +/- 0.41 (subgroup B); and +5.13 +/- 0.61 (subgroup C). In the smaller OZ group, they were +1.31 +/- 0.74, +2.56 +/- 0.28, and +5.28 +/- 0. 69, respectively. At 12 months, the distribution of eyes in the 5.9 mm OZ group with refractions within +/-1.0 D were as follows: subgroup A, 100%; subgroup B, 100%; and subgroup C, 94.2%. In the smaller OZ group, the distributions were 100%, 95.3%, and 71.4%. In the 5.9 mm and the smaller OZ groups, the UCVA was 20/40 or better in 92.0% and 81.8% of eyes, respectively, in subgroup A; 94.6% and 100%, respectively, in subgroup B; and 76.5% and 77.9%, respectively, in subgroup C. The percentage of eyes with 0 +/- 1 line of BCVA 12 months after the procedure was also determined in the 5.9 mm OZ group and compared with the percentages in the smaller OZ group. CONCLUSION: Results of hyperopic LASIK with a 5.9 mm OZ in eyes with low, moderate, and high hyperopia are more stable, predictable, and safe than those in eyes with OZs smaller than 5.9 mm.

Adult↗
PubMed1999

Laser in situ keratomileusis versus arcuate keratotomy to treat astigmatism.

PURPOSE: To analyze the effectiveness of laser in situ keratomileusis (LASIK) and arcuate keratotomy (AK) to treat simple myopic, compound myopic, and mixed astigmatism. SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: This retrospective nonrandomized study comprised 821 cases treated with LASIK and 46 cases treated with AK. Patients were divided into 4 groups, which had the following preoperative cylinder corrections: simple myopic astigmatism (Group 1) (LASIK: n = 76, -3.91 diopters [D] +/- 1.29 [SD]; AK: n = 5, -3.85 +/- 0.65 D); compound myopic astigmatism up to 2.00 D (Group 2) (LASIK: n = 401, -1.69 +/- 0.76 D; AK: n = 14, -1.48 +/- 0.41 D); compound myopic astigmatism over 2.00 D (Group 3) (LASIK: n = 253, -3.61 +/- 0.89 D; AK: n = 16, -3.09 +/- 0.84 D); mixed astigmatism (Group 4) (LASIK: n = 91, +3.65 +/- 1.62 D; AK: n = 11, 4.39 +/- 0.92 D). RESULTS: Six months postoperatively, the cylinder's vector-corrected change was as follows: Group 1, LASIK 3.75 +/- 1.08 D, AK 3.16 +/- 0.84 D; Group 2, LASIK 1.55 +/- 1.12 D, AK 1.34 +/- 0.44 D; Group 3, LASIK 3.39 +/- 0.98 D, AK 2.70 +/- 1.21 D; Group 4, LASIK 3.77 +/- 1.43 D, AK 3.75 +/- 0.89 D. Respective mean uncorrected visual acuities in each group were as follows: Group 1, 0.71 +/- 0.12 and 0.60 +/- 0.12; Group 2, 0.83 +/- 0.12 and 0.78 +/- 0.24; Group 3, 0.78 +/- 0.18 and 0.48 +/- 0.24; Group 4, 0.69 +/- 0.21 and 0.55 +/- 0.18. CONCLUSIONS: The vector-corrected change and visual acuity achieved with LASIK were better, although not significantly, than those attained with AK except for the UCVA obtained with LASIK in eyes with compound myopic astigmatism over 2.00 D. Both methods proved to be safe.

Astigmatism↗
PubMed1998

Laser in situ keratomileusis for hyperopia.

PURPOSE: To evaluate the results of laser in situ keratomileusis (LASIK) to treat hyperopia. SETTING: Instituto de la Vision, Buenos Aires, Argentina. METHODS: This nonrandomized study comprised 679 eyes of 321 patients having LASIK. Patients were divided into three groups based on preoperative spherical equivalent: Group A (low hyperopia, 2.00 diopters [D] or less); Group B (moderate hyperopia, between 2.00 and 3.00 D); Group C (high hyperopia, more than 3.00 D). The following were measured postoperatively: uncorrected visual acuity (UCVA); best spectacle-corrected visual acuity (BSCVA); refraction (evolution and distribution); lines of visual acuity gained and lost. Follow-up was 1 month in 79.4% of cases, 3 months in 75.5%, 6 months in 68.5% and 1 year in 38.3%. RESULTS: Six months after LASIK. 100% of cases in Group A, 95.3% in Group B, and 71.4% in Group C were within +/- 1.00 D of emmetropia; UCVA was 20/40 or better in 94.1, 100, and 87.8%, respectively. The percentage losing or gaining 0 +/- 1 line of BSCVA was 100, 97.6, and 100, respectively. CONCLUSIONS: Laser in situ keratomileusis was predictable and safe in the treatment of low and moderate hyperopia.

Adult↗
PubMed1997

Treatment of hyperopic astigmatism.

PURPOSE: To analyze the results after laser-assisted in situ keratomileusis (LASIK) treatment for positive cylinder at the flattest meridian. SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: A prospective, nonrandomized study was conducted. Patients were divided into three groups: (1) simple hyperopic astigmatism (SHA); 15 eyes with a mean preoperative cylinder of +3.37 diopters (D) +/- 1.62 (SD); compound hyperopic astigmatism (CHA); 75 eyes with a mean preoperative cylinder of +3.34 +/- 1.39 D; (3) mixed astigmatism (MA); 73 eyes with a mean preoperative cylinder of +3.45 +/- 2.15 D. In all eyes, treatment of the cylinder was performed at the flattest meridian by LASIK using the Chiron-Technolas Keracor 116/117 laser. The following parameters were analyzed over time: uncorrected visual acuity; best corrected visual acuity; correction of the spherical equivalent and the cylinder; lines of visual acuity gained and lost. RESULTS: Six months after the procedure, refractive cylinder was reduced to +0.58 +/- 1.22 D in the SHA group, +0.12 +/- 1.23 D in the CHA group, and -0.11 +/- 1.28 D in the MA group. Uncorrected visual acuities were 20/20 or 20/25 in 66.7, 60.4, and 76.5% of the groups, respectively. CONCLUSIONS: Use of the LASIK technique with the Keracor laser to treat positive cylinder at the flattest meridian corrected simple and compound hyperopic astigmatism and mixed astigmatism with good predictability and safety. This treatment has not produced a hyperopic refractive change at the opposite meridian.

Adult↗
PubMed1990

The effect of various degrees of unilateral spermatic cord torsion on fertility in the rat.

Unilateral spermatic cord torsion has been shown to cause damage to the contralateral testis in humans and animal models. In an attempt to explain conflicts among various laboratories concerning the extent of this contralateral effect and to determine the importance of the extent of torsion, prepubertal rats (35 to 40 days) were subjected to unilateral spermatic cord torsion of various degrees (zero to 1440 degrees). Sham surgeries were performed and served as controls (0 degrees of torsion). The animals were allowed to recover from the surgeries and to attain puberty before a period of fertility testing. Fertility, fecundity, organ weight and testicular histological data were obtained after the breeding period. Our data indicate that animals undergoing 360 degrees of torsion exhibited no changes in the parameters studied. However, if 720 degrees, 1080 degrees or 1440 degrees of torsion was induced, a significantly lower percentage of fertile males and pregnant females resulted for each of these experimental groups when compared to those values for the 0 degrees controls. These data indicate that the extent of contralateral testicular degeneration is dependent upon the degree of spermatic cord torsion to which the ipsilateral testis is subjected. The induction of unilateral spermatic cord torsion at 720 degrees or more causes a significant reduction of subsequent fertility while torsion of a lesser degree has little or no effect in the development of this phenomenon.

Animals↗
PubMed1990

Pyrimethamine: an approach to the development of a male contraceptive.

With the human population of the world currently more than 5.2 billion and growing at an explosive rate, the need for additional forms of readily available contraception appears paramount. To date, contraception techniques in the male have been very limited. The present study demonstrates the ability of pyrimethamine (PYR) to cause spermatogenic arrest and male infertility in mice in a dose-dependent manner. Furthermore, upon cessation of drug administration all animals returned to normal fertility status. It is also suggested that the action of PYR is due to its antifolate action. Thus, PYR represents another approach toward development of a male contraceptive.

Animals↗
PubMed1987

Zinc sulfate therapy for infertile male with or without varicocelectomy.

One hundred one men were treated for infertility with 440 mg of zinc sulfate daily for sixty days to two years. All subjects demonstrated low seminal plasma zinc concentrations prior to treatment. Patients were divided into two groups: group [Zn], 65 subjects who underwent zinc therapy alone and group [Var/Zn], 36 subjects who received zinc sulfate therapy after varicocelectomy. In both groups seminal zinc levels were significantly higher (P less than 0.05 and P less than 0.01, respectively) two months after the initiation of zinc therapy. There were no significant changes in sperm count or motility for the [Zn] patients. However, group [Var/Zn] showed a significant increase (P less than 0.05) of sperm motility at two months and twelve months after starting zinc sulfate therapy. We separated the [Var/Zn] patients into two sub-divisions: those who impregnated their wives after therapy, and those who remained infertile despite treatment. Only those patients who impregnated their wives showed a significant (P less than 0.05) increase in sperm motility two months after the initiation of zinc therapy. Those patients of the [Var/Zn] group who remained infertile despite treatment showed a significant increase (P less than 0.05) in sperm motility after twelve months of therapy. Of the [Zn] patients 27.7 per cent (18) successfully impregnated their wives, while the [Var/Zn] patients exhibited a pregnancy rate of 50 per cent (18 patients). These data indicate that zinc sulfate therapy for patients with low seminal zinc concentrations may be an effective treatment for infertile patients especially after varicocelectomy.

Humans↗
PubMed1987

Significance of testicular size measurement in andrology: II. Correlation of testicular size with testicular function.

The testicular sizes of 305 men were measured by a recently developed orchidometer and related to 9 other known parameters of testicular function. Mean testicular size had the strongest correlation with serum follicle-stimulating hormone levels, total sperm count and sperm concentration, while a significant correlation also was noted with sperm motility, percentage of live sperm, sperm morphology (normal and immature forms), and serum luteinizing hormone and testosterone levels. Sperm quantity had stronger correlations with testicular size than did sperm quality, although both were impaired in testes smaller than 14 ml. It is concluded that the size of the testis bears a direct correlation with testicular function and, thus, it can be helpful to assess rapidly andrological status during the initial physical examination.

Adult↗
PubMed1986

Structure and function of the epididymis.

Testicular spermatozoa are functionally immature in that they cannot fertilize ova. It was first demonstrated by Young that spermatozoa undergo certain changes as they migrate through the epididymis. He proposed that spermatozoa ripen during epididymal transit. It is now known that specific maturational changes occur in spermatozoa during epididymal transit which result in their developing the ability to fertilize ova. Concomitant with this functional maturity are changes in spermatozoal morphology, motility, chemistry, permeability, density and metabolism. It is apparent that in some way not understood these changes are necessary for sperm to achieve the ability to complete the fertilization process. When these mechanisms are understood, we may be able to effectively treat conditions such as necrospermia or abnormally low sperm motility. Furthermore, with the development of the hamster-egg penetration test a "new" type of male infertility has become evident in recent years; the inability of otherwise normal sperm to penetrate an ovum. It is during epididymal transit that this ability is normally acquired. Thus, any insight into how sperm attain the capacity to penetrate an ovum could lead to an effective treatment of patients whose sperm do not have this ability. In addition, the epididymis holds significant promise as the site of action for a male contraceptive. Thus, it is the purpose of this review to describe the structure and function of the mammalian epididymis with particular emphasis on the factors regulating sperm maturation.

Androgens↗
PubMed1986

The effect of graded unilateral testicular biopsy on the reproductive capacity of male rats.

Fifty adult rats were subjected to unilateral testicular biopsy removing either 0.01, 0.1, 0.2 or 0.3 cc of testicular parenchyma. In addition, 20 rats underwent either hemicastration or sham surgery. After a 30-day recovery period each male was housed with two cycling females for 20 days. At the end of this breeding trial the percentage of fertile males, percentage of pregnant females and resulting embryo scores (no. of embryos X size of embryos) were determined for each group of male rats. After an additional 30 days (60 days post-biopsy) a second breeding trial was performed so as to note any long-term changes in fertility. In addition to the fertility parameters, mean seminiferous tubule diameters and serum testosterone levels were noted. After the first breeding trial the percentage of fertile males and percentage of pregnant females were inversely proportional to the amount of biopsy material removed (p less than 0.05). However, the hemicastrate and sham-operated groups did not differ from the O cc control animals. The results of the second breeding trial showed a significant improvement in the percentage of females becoming pregnant (p less than 0.05) and a tendency for improvement in the percentage of fertile males when compared to data of the first breeding trial. In addition, we found the mean seminiferous tubular diameter of the biopsied testes to be inversely proportional to the size of the biopsy (p less than 0.01) with no apparent effect on the contralateral testes. We conclude that removing relatively large amounts of testicular parenchyma during unilateral testicular biopsy transiently affects male reproductive capacity, at least in the healthy animal model studied here.

Animals↗
PubMed1985

Histological changes occurring in the contralateral testes of prepubertal rats subjected to various durations of unilateral spermatic cord torsion.

Prepubertal rats were exposed to unilateral spermatic cord torsion for 0, 1, 3, 5, 9 or 12 hours duration. At the end of this time the damaged testes were either removed or untwisted and pexed into place. The animals were then allowed to mature to 77 days of age at which time the contralateral testes were examined for 12 histological parameters and scored according to the degree of pathology noted in each. Pathological changes in the contralateral testes were found to be dependent on the duration of spermatic cord torsion but were less severe in the orchiectomized group. Thus, removal of the damaged organ minimized the long-term damage to the contralateral testes. We also noted that specific histological parameters of the contralateral testes correlated well with fertility and that specific changes in the ipsilateral testes predicted contralateral pathology.

Animals↗
PubMed1984

Effect of sympathetic denervation of rat internal genitalia on daily sperm output.

Using the technique of vasocystostomy, daily sperm output was determined in rats undergoing surgical removal of the sympathetic nerves to the internal genitalia. Between ten and fourteen days after denervation, the daily sperm output significantly (p less than 0.001) decreased below presurgical rates and those of sham-operated control animals (p less than 0.01). This change occurred without changes in plasma testosterone concentration or testicular histology. These data suggest neural control of sperm transport in the rat.

Animals↗
PubMed1984

The varicocele.

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Animals↗