Avaliação da eficácia de um novo marcador cirúrgico para capsulorrexe anterior / Effectiveness evaluation of a new surgical marker for anterior capsulorhexis

RESUMO Objetivo: Avaliar a eficácia de um novo marcador cirúrgico para ajudar na confecção da capsulorrexe anterior analisando o seu dimensionamento e formato, comparando com a capsulorrexe confeccionada manualmente de maneira livre. Métodos: Como experimento, 3 residentes (R3) de Oftalmologia do Hospital Universitário Onofre Lopes (HUOL) e 1 oftalmologista em treinamento, voluntários, realizaram (cada um) 10 capsulorrexes em olhos de porco enucleados. Em 5 olhos foi utilizado o marcador e em outros 5, não. Todos os olhos foram fotografados tendo ao lado uma régua para orientar e calibrar um aplicativo para a avaliação morfométrica do procedimento. O diâmetro alvo foi de 5 mm, cujo perímetro correspondente é 15,7 mm e a área 19,652 mm2. Foram avaliados em cada procedimento: os diâmetros máximo, mínimo e médio, o perímetro, a área e o desvio em relação ao diâmetro e quanto ao aspecto ideal. Resultados: No grupo utilizando o marcador o diâmetro médio foi 5,44mm (±0,89) contra 6,37mm (±0,67) (p=0,001), no grupo no qual não se utilizou o marcador; quanto ao perímetro, 17,52mm (±1,92) no grupo utilizando o marcador contra 20,14mm (±2,09) (p<0,001) sem o marcador e quanto a área, 24,73mm2 (±1,92) com o marcador, contra 32,62mm2 (±6,32) (p<0,001), sem o marcador. Em relação ao aspecto da capsulorrexe 1,26mm (±0,12), contra 1,21mm (±0,7) (p=0,09) e em relação ao desvio de curvatura: 0,87 (±0,05), contra 0,9 (±0,04), (p=0,06) respectivamente. Conclusão: O trabalho mostrou que o marcador avaliado é eficaz para auxiliar a confecção da capsulorrexe conduzindo a resultados melhores que o método a mão livre.

ABSTRACT Purpose: To evaluate the effectiveness of a surgical device that intented to help in the preparation of the anterior capsulorhexis analyzing the design and shape, comparing with capsulorhexis made by free hand. Methods: Three ophthalmology residents(R3) at the HUOL and one surgeon in training, participate in this research as volunteers. Each surgeon perform 5 capsulorhexis in porcine eyes using the device, and five others by free hand as a control. All capsulorhexis were photographed having a ruler as reference to guide and calibrate a computer application for morphometric evaluation (Cambuí Labs, Natal, Brazil). All surgeons aimed to produce a circular continuous capsulorhexis of 5 mm diameter that represents 15,7mm in perimeter and 19,652mm2 in area. Each wet-lab capsulorhexis was evaluated in regard to these criteria: diameter (mean, maximum and minimum), perimeter, area, deviation from the ideal diameter and ideal shape. Results: Compare to control groups, capsulorhexis with the aid of the surgical device showed: 5,44mm ±0,89 vs 6,37mm ±0,67, for capsulorhexis diameter (p=0,001); 17,52mm ±1,92 vs 20,14mm ±2,09 for capsulorhexis perimeter (<0.001); 24,73mm2 ±1,92 vs 32,62mm2 ±6,36 for capsulorhexis area (p<0,001). A tendency for better result with the aid of the surgical device was observed for deviation of an ideal diameter or ideal aspect were appreciated: 0,87mm ±0,05 vs 0,9 ±0,04 for deviation of a curve (p=0,06); 1,26mm ±0,12 vs 1,21mm ±0,7 for the capsulorhexis aspect (p=0,09). Conclusion: Capsulorhexis produced with the aid of the surgical device, significantly improved wet-lab capsulorhexis performance.

Trans-differentiation of iris pigmented epithelial cells of Euphlyctis cyanophlyctis tadpoles into lens in vitro.

Meshed pigmented iris epithelium along with neural retina of tadpoles of the frog Euphlyctis cyanophlyctis were found to undergo dedifferentiation and subsequently transdifferentiate into lens in culture medium. During lag period, depigmentation (dedifferentiation) occurred in many cells. When culture became confluent 3-4 weeks after seeding tiny lens like structures differentiated from foci of cultured pigmented iris epithelium cells. The percentage of lens formation was higher in vitamin A treated cases. The culture system appears to be a suitable for investigating the changes occurred during trans-differentiation of pigmented epithelial cells into lens.

Protective Effect of Catechin on Apoptosis of the Lens Epithelium in Rats with N-methyl-N-nitrosourea-induced Cataracts

PURPOSE: To investigate the effect of catechin on apoptotic cell death in the lens epithelium of rats with cataract. METHODS: Cataract was induced by intraperitoneal injection of 100 mg/kg N-methyl-N-nitrosourea (MNU) to ten day-old Sprague-Dawley rats. The neonatal rats were randomly divided into five groups (n=15 in each group): a control group, and four cataract-induction groups, treated with either 0, 50, 100, 200 mg/kg catechin. We performed slit-lamp biomicroscopic analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, Western-blot for Bcl-2 and Bax, and immunohistochemistry for caspase-3. RESULTS: Apoptotic cell death in lens epithelial cells that increased following cataract formation in rats was suppressed by cathechin. CONCLUSIONS: Catechin inhibited cataract-induced apoptotic cell death in the lens epithelium and may prove useful for the prevention of cataract progression.

Preventive effect of onion juice on selenite-induced experimental cataract.

Purpose: To evaluate the effects of onion juice on sodium-selenite induced cataract formation. Materials and Methods: Thirty-two 10-day-old Wistar-albino rat pups were divided into four equal groups. Group 1 received only subcutaneous saline injection. In Group 2, sodium-selenite (30 nmol / g body weight) was injected subcutaneously. In Group 3, subcutaneous sodium-selenite was injected and one drop 50% diluted fresh juice of crude onion was instilled every 8 h into the right eye for 14 days; the left eye received no treatment. Group 4 rats were similar to those of Group 3, the only difference being that of undiluted fresh juice of crude onion. The development of cataract was assessed. Rat lenses were analyzed for total antioxidant (TA) level, and for activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD). Results: Both eyes of all rats in Group 1 did not exhibit cataract formation . In Group 2, all rats developed Grade 3 cataract in the lenses of both eyes. The difference in exhibited cataract in the lens of the right eyes in all rats between Group 2 and any eyes of groups 3 or 4 were significant ( P = 0.001). The mean TA level and mean activities of SOD and GPX in Group 2 rat lenses were significantly lower than the values in lenses of all rats in Group 1 ( P = 0.001, 0.003, 0.001), and in the lenses of the right eyes of rats in Groups 3 and 4 ( P = 0.001, 0.020, 0.001). Conclusion: Instillation of onion juice into the rat eyes can effectively prevent selenite-induced cataract formation. This effect was associated with increased TA level, SOD and GPX activities in the lens.

Effect of Emblica officinalis (Gaertn) on lens regeneration in the frog, Rana cyanophlyctis (Schneider).

Emblica officinalis (Amla) accelerated cell proliferation and dedifferentiation of pigmented epithelial cells of dorsal iris and consequently induced lens regeneration in R. cyanophlyctis. Further it enhanced the percentage of lens regeneration not only in young tadpoles but also is adult frogs. Lens regeneration ability declined with the age of animals in both control as well as treated groups.

Cumulative antioxidant defense against oxidative challenge in galactose-induced cataractogenesis in Wistar rats.

Natural dietary ingredients are known for their antioxidant activity. Of such, curcumin, the active principle of turmeric, at 0.01% in the diet proved as pro-oxidative in galactose-induced cataract in vivo. The purpose of this study was to investigate the effect of vitamin E (VE), a well-known antioxidant, in combination with curcumin on the onset and maturation of galactose induced cataract. Periodic slit-lamp microscope examination indicated that in combination with vitamin-E, 0.01% curcumin (G-IV) delayed the onset and maturation of galactose-induced cataract. Biochemical analyses revealed that combined treatment of 0.01% curcumin and vitamin-E diet exhibited an efficient antioxidant effect, as it inhibited lipid peroxidation and contributed to a distinct rise in reduced glutathione content. The results indicate that natural dietary ingredients are effective in combination rather than the individual administration as they are complementing each other in reducing the risk of galactose induced cataract.

Effect of vitamin A on lens regeneration in pigs.

Intraperitoneal injections of vitamin A (0.5 ml of 1500 IU/ml) to lentectomized pigs on alternate days up to 60 th day after lentectomy induced lens regeneration in not only 10 days old young ones but also in 40 and 100 days old pigs. Lens regeneration did not occur even in a single case of control groups. In shape, size, transparency and histological features regenerated lenses were similar to normal intact lenses. The experimental model is the first to show that mitogenic and dedifferentiate activity of vitamin A can induce iris pigmented epithelial cells to trans-differentiate into new lens in pigs.

Intraocular irrigating solutions. A clinical study of BSS Plus and dextrose bicarbonate fortified BSS as an infusate during pars plana vitrectomy.

PURPOSE: To compare the effect of Balanced Salt Solution Plus (BSS Plus, Alcon Laboratories, Fort Worth, Texas, USA) and fortified regular BSS on the cornea and lens, when used for continuous irrigation in pars plana vitrectomy (PPV) surgery. METHODS: Prospective, investigator masked, randomised study. Forty patients were randomly assigned to undergo PPV using BSS Plus (n=20) or fortified BSS (n=20) [regular BSS, fortified with 10.5 cc. of dextrose in water (D5W) and 13.1 cc. of 8.4% sodium bicarbonate]. Intraoperative features of the corneal epithelium, postoperative changes in the corneal endothelial cell denstiy (ECD) at 3 months, and clarity of the lens during surgery and postoperatively were evaluated. RESULTS: Intraoperative epithelial changes were similar in both groups with 7 (35%) of the cases having the epithelium removed in the BSS Plus group and 8 (40%) in the BSS fortified group (P=0.23). The mean differences in ECD (3 months versus preoperative) in the operated eyes when adjusted for changes in the control eye showed no difference with the type of BSS (P=0.98). Intraoperative lens changes were more significant (P=0.018) in the BSS fortified group. Postoperative lens status at 3 months was similar for both groups. Though there was a trend towards worse postoperative nuclear sclerosis change in the BSS fortified group, it was not significant (P=0.160). CONCLUSION: Standard BSS fortified with dextrose and bicarbonate is an efficacious infusion fluid during pars plana vitrectomy. Both solutions showed comparable effects on postoperative corneal endothelial cell density and corneal epithelial changes intraoperatively. BSS fortified has more lenticular changes intraoperatively than BSS Plus although no lens had to be removed in either group. The study implications are important since BSS fortified is significantly less expensive than BSS Plus.

Lens regeneration in mice under the influence of vitamin A.

The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 IU/ml in adult) was given to the operated animals. Vitamin A was found to induce lens regeneration in not only young but also in adult mice. Regenerated lenses were similar in shape, size, transparency and histological features to normal intact lenses.

The effective concentration and exposure time of mitomycin-C for the inhibition of lens epithelial cell proliferation in rabbit eyes

The proliferation of residual lens epithelial cells following cataract surgery is assumed to be a major cause of posterior capsular opacification. To assess the efficacy of mitomycin-C in preventing posterior capsular opacification, we determined the effective concentration and exposure time of mitomycin-C in inhibiting rabbit lens epithelial cell proliferation. The fourth-passaged rabbit lens epithelial cells were maintained for one day and then exposed to mitomycin-C for 1, 2, 3, and 5 minutes, respectively. There were 9 different plating concentrations of mitomycin-C with two-fold serial dilution. The maintenance of the phenotypic properties of lens epithelial cells was confirmed by continuous transcription of lambda-crystalline mRNA determined by reverse transcription-polymerase chain reaction and the polymorphism of the restriction fragment. Cell proliferation was assayed with 3H-thymidine incorporation into DNA. The fourth-passaged cells maintained the expression of lambda-crystalline mRNA, suggesting that they are phenotypically authentic lens epithelial cells. The effective concentrations and exposure time of mitomycin-C were 0.1 mg/ml for 1 minute and 2 minutes, and 0.025 mg/ml for 2 minutes. By these results, we postulated that mitomycin-C at relatively short incubation times could be clinically used for prevention of posterior capsular opacification after cataract surgery.

Effect of vitamin B6 on lenses of diabetic rats.

Vitamin B6 is essential for the metabolism of fat, carbohydrate and protein. In this study the effect of vitamin B6 on diabetes induced impairments in rat lenses was investigated. Although macroscopic examination revealed no opacification of rat lenses in any groups, uncontrolled induced diabetes caused significant decreases in lens glutathione and increases in lens protein nonenzymatic glycosylation and blood glucose. Administration of vitamin B6 did not inhibit these diabetes induced alterations significantly. SDS-polyacrylamide gel electrophoresis revealed some significant differences in some protein bands between groups.

Topical aspirin provides protection against galactosemic cataract.

Effect of twice daily administration of aspirin eyedrops on the onset and progression of cataract induced by 30% galactose diet was studied. On the 30th day of galactose feeding while all control group rats showed complete stage IV opacity, those receiving aspirin eyedrops showed only mild cataractous changes of stage I. In vitro studies showed that addition of aspirin to the medium significantly decreased dulcitol formation (p < 0.01) and maintained glutathione levels (p < 0.02). Intraocular penetration studies using isolated goat cornea showed excellent penetration by salicylate indicating feasibility of topical administration. The results of the present study demonstrate that topical aspirin possesses significant anticataract activity in galactosemic cataract.

Açäo da mitomicina C nas estruturas intraoculares de coelhos / Action of mitomicin C in intraocular structure of rabbits

Injetamos no espaço vítreo, mitomicina C em concentraçöes de 0,1 mg/0,1 ml e 0,5 mg/0,1 ml e, deixamos a droga ser absorvida nos tecidos oculares, por difusäo, sem removê-la cirurgicamente. A mitomicina é altamente lesiva para a retina, coróide e corpo ciliar, levando à necrose isquêmica desses tecidos nas duas concentraçöes usadas (o,1 mg e 0,5 mg) sendo que as alteraçöes da retina e do cristalino foram mais graves no grupo de maior concentraçäo e nesse grupo os olhos foram para atrofia. A necrose total da retina ocorreu em todos os olhos do grupo 2 (mitomicina 0,5 mg) (100 por cento) e em 21 por cento dos olhos do grupo 1 (mitomicina 0,1mg) neste grupo houve maior incidência de necrose parcial da retina (63,9 por cento). A incidência de necrose parcial da retina (63,9 por cento). A incidência de necrose isquêmica da coróide e corpo ciliar também foram maiores no grupo 2 (mitomicina 0,5 mg), tendo ocorrido necrose total em todos os olhos neste grupo.

Effect of ophthalmic irrigating solutions on biophysical properties of lens, aqueous and vitreous humours

In a series of comparative studies to decide which of BSS plus, BSS or Ringer's lactate irrigating solution is mimic as closely as possible to aqueous humor and vitreous body, so as to maintain normal ocular metabolism and integrity of the ocular functions which should be preserved. New Zealand mature rabbits were used to study the effect of mentioned irrigating solutions on the molecular weight distribution and electrophoretic mobilities of lens aqueous and vitreous humors after 72 hours of the eye in vivo irrigation. The presented study showed a significant fluctuations in the molecular weight distribution and electrophoretic mobilities of BSS irrigating solution, while it is nearly the same profile as in the normal control group in case of eyes irrigated with BSS plus and Ringer's lactate solutions. From the results of the presented study and that of previous research of our collegues, it is preferable to use Ringer's lactate solution widely as it is cheaper and safer to the eye than the other maintained studied irrigating solutions

In vivo effect of cyanate on serum and eye lens in rat.

Supplementation of cyanate in rats caused a significant decrease in serum GSH and increase in calcium and phosphate level both in serum and lens. Consequently, these changes led to induce acidosis uremia in serum and hypercalcemia and hyperphosphatemia in lens which may be possible causing factor for cataract.

Ultrasonic study to see the effect of topical pilocarpine and homatropine on anterior chamber depth in phakic cases.

Pilocarpine and Homatropine are the drugs having known effect on the depth of anterior chamber. The purpose of this study was to demonstrate the time of onset, peak effect and its duration of action as well as shallowing/deepening of the anterior chamber, after single instillation of pilocarpine 2% or homatropine bromide 2%, topically in one eye. Also we tried to see if there is any effect on the contralateral eye, due to systemic absorption of pilocarpine, homatropine after topical instillation of the drug in one eye. Pilocarpine causes a measurable shallowing of the anterior chamber with onset of effect with in 20 minutes and a peak in 60 minutes, the average narrowing being 0.26 mm. (range 0.20-0.29 mm.). Homatropine has a measurable deepening effect on the anterior chamber, due to axial flattening of the lens because of cycloplegia, with a range of 0.33 to 0.36 mm. In 70% of the cases the effect passes away with in 24 hours., but in 30% it comes to normal in 48 hours.

Naphthol and lens.

Alpha and beta naphthols, the metabolites of naphthalene, a cataractogenic agent, was tested for it's effect on sheep lens proteases and their inhibitors. It reduced protease activities, not that of inhibitor activities of lens proteins. It also increased the efflux of free amino acid from lenses which was retarded by a high concentration of tissue galactose.

Glutathione and glutathione-related enzymes in busulfan treated rat lens.

Glutathione (GSH) and GSH-related enzymes, glutathione reductase (GR), gamma-glutamyl cysteine synthetase (gamma-GCS), gamma-glutamyl transpeptidase (gamma-GTP), glutathione S-transferase (GST) and adenosine triphosphatase (ATPase) enzymes were analysed to study the effect of busulfan on the defence mechanisms of the lens. All these enzymes were found to increase significantly except GSH which showed only 7.9% increase as compared to controls in precataractous stage. These results affirm that busulfan is capable of evoking a response from the enzymes involved in the various pathways of GSH enabling the lens to prolong its clarity. The cataractous lenses showed significant decrease in all these parameters. Here, the impairment of the defense mechanism (GST, GR) and the total ATPase may be attributed to the cumulative action of the drug which can react with -SH groups of these enzymes, ultimately causing opacification.