Use of viscoelastic substance for preventing Descemet's membrane rupture in deep anterior lamellar keratoplasty / Uso de substância viscoelástica na prevenção da ruptura da membrana de Descemet na ceratoplastia lamelar anterior profunda

ABSTRACT Purpose: This study aimed to investigate the effect of using a viscoelastic substance in Descemet's membrane rupture in "double bubble" deep anterior lamellar keratoplasty. Methods: The medical records and videos of surgeries of 40 patients who underwent surgery between January 2014 and July 2015 were retrospectively evaluated. The patients were divided into two groups: 20 patients whose perforation of the posterior stromal wall was performed without administration of any viscoelastic substance (group 1) and 20 patients whose perforation of the posterior stromal wall was performed with administration of viscoelastic substance onto the posterior stroma (group 2). The Descemet's membrane perforation rate was compared between groups. Results: Perforation of the Descemet's membrane was observed in 12 (60.0%) patients in group 1 and only three (15.0%) patients in group 2. This difference was statistically significant (p=0.003). Only one (5%) patient in group 2 had macroperforation during the procedure, and the surgery was converted to penetrating keratoplasty. Eleven (55.0%) patients in group 1 had macroperforation of Descemet's membrane, and surgeries were converted to penetrating keratoplasty. This difference between the groups was statistically significant (p=0.001). Conclusions: Administering a viscoelastic substance onto the posterior stromal side just before puncture is an effective method to decrease the risk of Descemet's membrane perforation in deep anterior lamellar keratoplasty.(AU)

RESUMO Objetivo: Investigar o efeito do uso de uma substância viscoelástica na ruptura da membrana de Descemet em casos de ceratoplastia lamelar anterior profunda em "bolha dupla". Métodos: Foram avaliados retrospectivamente prontuários e vídeos de cirurgias de 40 pacientes operados entre janeiro de 2014 e julho de 2015. Os pacientes foram divididos em dois grupos: 20 pacientes nos quais a parede posterior do estroma foi puncionada sem a colocação de nenhuma substância viscoelástica (grupo 1) e 20 pacientes nos quais uma substância viscoelástica foi aplicada sobre o estroma posterior ao ser puncionada a parede posterior do estroma (grupo 2). A taxa de perfuração da membrana de Descemet foi comparada entre os grupos. Resultados: Observou-se perfuração da membrana de Descemet em 12 casos (60,0%) no grupo 1 e em apenas 3 casos (15,0%) no grupo 2. Essa diferença foi estatisticamente significativa (p=0,003). Apenas um caso (5%) no grupo 2 teve macroperfuração durante o procedimento, sendo a cirurgia então convertida em uma ceratoplastia penetrante. Onze casos (55,0%) no grupo 1 tiveram macroperfuração da membrana de Descemet e essas cirurgias foram convertidas em ceratoplastias penetrantes. Essa diferença entre os grupos foi estatisticamente significativa (p=0,001). Conclusões: A aplicação de substância viscoelástica sobre o lado posterior do estroma logo antes da punção é um método eficaz para diminuir o risco de perfuração da membrana de Descemet na ceratoplastia lamelar anterior profunda.(AU)

Liver transplantation in Jehovah's Witnesses: a case series / Experiencia en trasplante hepático para testigos de Jehová: serie de casos

Abstract Introduction: Orthotopic liver transplantation (OLT) is a procedure characterized by high bleeding rates and a significant likelihood of exposure to blood products. Objectives: This case series shows the experience at a referral center for Jehovah's Witnesses (JW) with end-stage liver disease, undergoing OLT. Materials and methods: A search was conducted in our database of JW undergoing OLT between July 2007 and August 2012. The information about their pre-operative condition and progress up to 30 days post-transplantation. Results: Four subjects were identified (3F/1M) with an average age of 42 years (range 22-55). All of them received a multidisciplinary management which included pre-operative optimization of red cell mass, antifibrinolytic prophylaxis, and cell salvage (mean volume of 344mL [range 113-520]). The average intraoperative bleeding volume was of 625mL (range 300-1000). One of the patients presented with a primary graft dysfunction and died, while the rest had a normal postoperative course. Conclusion: It is possible to offer OLT to patients who refuse to receive allogeneic blood transfusions, through a comprehensive approach that includes perioperative hematologic optimization and the use of blood conservation measures, without a significant impact on the outcomes.

Resumen Introducción: El trasplante hepático ortotópico (THO) es un procedimiento caracterizado por índices significativos de sangrado y alta probabilidad de exposición a hemocomponentes. Objetivos: Esta serie de casos muestra la experiencia de un centro de referencia en la atención de testigos de Jehová (TJ) con enfermedad hepática terminal llevados a THO. Materiales y métodos: Se realizó una búsqueda en nuestra base de datos de TJ que hubiesen sido llevados a THO entre julio de 2007 y agosto de 2012. Se registraron datos correspondientes a su estado preoperatorio, manejo perioperatorio y evolución hasta los 30 días postrasplante. Resultados: Se encontraron cuatro sujetos (3M/1H) con una edad promedio de 42 años (rango de 22-55). Todos recibieron un manejo multidisciplinario que incluyó la optimización preoperatoria de su masa eritrocitaria, profilaxis antifibrinolítica y salvamento celular [volumen promedio de 344 ml (rango de 113-520)]. El volumen promedio de sangrado intraoperatorio fue de 625 ml (rango de 300-1000). Uno de los pacientes presentó disfunción primaria del injerto y muerte, mientras que los demás tuvieron un curso posoperatorio convencional. Conclusiones: Es posible ofrecer la posibilidad de THO para sujetos que se niegan a recibir transfusiones alogénicas, por medio de un abordaje integral que incluya la optimización hematológica perioperatoria y la utilización de medidas de conservación sanguínea, sin que esto afecte significativamente los resultados.

Comparação prospectiva e randomizada entre DisCo Visc e hidroxipropilmetilcelulose 2(porcento) durante a facoemulsificação / Prospective randomized comparison of DisCoVisc and 2(porcento) hydroxypropylmethilcellulose in phacoemulsification

INTRODUÇÃO: Comparar duas soluções viscoelásticas, ácido hialurônico 1,6%/sulfato de condroitina 4% (DisCoVisc®, Alcon Laboratórios, EUA) e hidroxipropilmetilcelulose 2% (HPMC, Ophthalmos, Brasil), com relação ao desempenho durante a facoemulsificação (FACO) e o implante de lente intraocular. MÉTODOS: Foi realizado um ensaio clínico randomizado, envolvendo 78 olhos (39 pacientes) submetidos à FACO bilateral, por um único cirurgião. Os pacientes foram randomizados para receber DisCoVisc ou HPMC no primeiro olho. O olho contralateral foi operado mais tarde recebendo a outra solução viscoelástica em todas as etapas da cirurgia. Examinadores mascarados realizaram as avaliações pré e pósoperatórias (5, 24 e 48 horas; 7 e 14 dias; 3 e 6 meses), incluindo a medida da pressão intraocular (PIO), espessura cornena central (ECC) e acuidade visual corrigida. A densidade endotelial foi realizada no pré-operatório e ao final do seguimento (6 meses). Variáveis intraoperatórias incluíram medidas da quantidade total de solução viscoelástica, tempo de ultrassom durante a FACO e tempo para a retirada completa da solução do olho. RESULTADOS: A densidade endotelial foi estatisticamente superior com DisCoVisc (2.214 ± 372 cel/mm2) do que com HPMC (2.032 ± 460 cel/mm2) ao final do seguimento (p = 0,001). Uma redução média de 7% e de 15%, respectivamente. Não houve diferença estatística entre as soluções viscoelásticas com relação a densidade da catarata (p = 0,363) e o tempo de ultrassom (p = 0,456). O tempo de aspiração da HPMC (0,22 ± 0,09 min) foi significativamente maior que o DisCoVisc (0,17 ± 0,06 min) (p = 0,001) e a quantidade de viscoelástico utilizada foi maior com a HPMC (1,35 ± 0,20 ml) do que com DisCoVisc (0,89 ± 0,11 ml) (p < 0,001). Não houve diferença estatisticamente significativa entre as soluções quanto a ECC e a PIO durante o seguimento. CONCLUSÕES: A densidade endotelial ao final do estudo foi significativamente maior com o uso de DisCoVisc, o que pode...

INTRODUCTION: To compare two ophthalmic viscosurgical devices (OVDs), 1.6% hyaluronic acid/4% chondroitin sulfate (DisCoVisc®, Alcon Lab., USA) and 2% hydroxypropylmethylcellulose (HPMC, Ophthalmos, Brazil), in terms of their overall performance during phacoemulsification (PHACO) and intraocular lens implantation. METHODS: This prospective, randomized clinical trial comprised 78 eyes (39 patients) that underwent PHACO by the same surgeon. Patients were randomly assigned to receive DisCoVisc or HPMC on the first eye. The other eye was treated later and received the other OVD. Masked examiners measured intraocular pressure (IOP), central corneal thickness (CCT) and best-corrected visual acuity. The corneal endothelial cell density was measured at baseline and at 6 months postoperatively. Intraoperative variables include the total amount of the OVD, ultrasound and washout times. RESULTS: Corneal endothelial cell density was significantly higher with DisCoVisc (2.214 ± 372 cell/mm2) than HPMC (2.032 ± 460 cell/mm2) at the end of follow-up (p = 0.001). A mean reduction of 7% and 15%, respectively. There were no statistically significant differences between OVDs in terms of cataract density (p = 0.363) or ultrasound time (p = 0.456). Regarding washout time, it took longer to remove HPMC (0.22 ± 0.09 min) than DisCoVisc (0.17 ± 0.06 min) (p = 0.001), and the amount of viscoelastic material used was greater with HPMC (1.35 ± 0.20 ml) than DisCoVisc (0.89 ± 0.11 ml) (p < 0.001). There were no statistically significant differences between the two OVDs regarding CCT or IOP measurements at any point in time. CONCLUSION: The corneal endothelial cell loss was significantly less with DisCoVisc than HPMC, which can improve corneal endothelium protection. DisCoVisc was easier to remove after IOL implantation and fewer amounts were necessary during PHACO.

Biomicroscopia ultrassônica na viscocanalostomia / Ultrasound biomicroscopy in viscocanalostomy

OBJETIVO: Estudar por biomicroscopia ultrassônica (UBM) de alta frequência as características anatômicas da viscocanalostomia, e a relação dessas características com a redução da pressão intraocular. MÉTODOS: Estudo transversal, que incluiu nove olhos (sete pacientes) submetidos à viscocanalostomia, e posteriormente examinados por UBM de alta frequência (80 MHz). Os parâmetros da UBM avaliados após um follow-up mínimo de seis meses foram: presença de espaço intraescleral, comprimento e altura máximos do espaço intraescleral, e a espessura mínima da membrana trabéculo-descemética (MTD) residual. O sucesso cirúrgico definiu-se como pressão intraocular (PIO) <22mmHg ou redução de 20% da PIO sem medicação tópica. Possíveis associações entre as variáveis da UBM e o resultado cirúrgico foram avaliados. RESULTADOS: O tempo médio entre a cirurgia e a realização da UBM foi de 15,5 ± 8,8 meses (6 - 29 meses). Verificou-se uma redução da PIO de 23,5 ± 6,9 mmHg (13,7-32,0) pré-operatória para 14,5 ± 2,4 mmHg (10,7-17,3) pós-operatória (p<0,05). Identificou-se a presença de espaço intraescleral em todos os olhos. A média do comprimento máximo do espaço intraescleral era 1,83 ± 0,51mm; a média da altura máxima do espaço intraescleral era 0,36 ± 0,17mm; e a média da espessura mínima da MTD era 0,14 ± 0,07mm. Não foram encontradas correlações significativas entre o valor da PIO pós-operatória e o comprimento do espaço intraescleral (r²=0,359), a altura do espaço intraescleral (r²=0,017) e a espessura da MTD (r²=0,003). CONCLUSÃO: Em pacientes submetidos à viscocanalostomia, a UBM após um follow-up mínimo de seis meses identificou o espaço intraescleral em todos os olhos. Não se encontrou qualquer correlação estatisticamente significativa entre os valores de PIO pós-operatória e as características anatômicas do espaço intraescleral.

PURPOSE: To evaluate by high frequency ultrasound biomicroscopy (UBM) the anatomical characteristics of viscocanalostomy and their relationship with the intraocular pressure (IOP) lowering. METHODS: A transversal study which included 9 eyes (7 patients) undergoing viscocanalostomy and examined by high frequency UBM (80 MHz). Several UBM variables were evaluated, including the presence of the intrascleral space, the maximum length and height of the intrascleral space and the minimum thickness of residual trabeculo-Descemet membrane (TDM). Surgical success was considered to be achieved when IOP was <22mmHg or the IOP was lowered 20% or more without the use of any medication. The possible association between UBM variables and the surgical outcome was determined. RESULTS: The mean time between surgery and the UBM examination was 15.5 ± 8.8 months (range 6-29). The mean IOP decreased from a preoperative value of 23.5 ± 6.9 mmHg (range 13.7-32.0) to 14.5 ± 2.4 mmHg (range 10.7-17.3) postoperative (p<0.05). The presence of an intrascleral space was a constant finding. The mean length of the intrascleral space was 1.83 ± 0.51mm, the mean height was 0,36 ± 0,17mm; and the mean TDM thickness was 0.14 ± 0.07mm. There were a poor correlation between the level of IOP at the time of UBM and the lenght of the intrascleral space (r²=0.359), the height of the intrascleral space (r²=0.017) or the thickness of the remaining TDM (r²=0.003). CONCLUSION: In patients undergoing viscocanalostomy, UBM examination after a minimum of 6-month follow-up period showed the presence of an intrascleral space in all patients. There was no statiscally significant relationship between the level of IOP and the anatomical characteristics of the intrascleral space.

Completion rates of anterior and posterior continuous curvilinear capsulorrhexis in pediatric cataract surgery for surgery performed by trainee surgeons with the use of a low-cost viscoelastic.

Context: Pediatric cataract surgery is traditionally done with the aid of high-molecular-weight viscoelastics which are expensive. It needs to be determined if low-cost substitutes are just as successful. Aims: The study aims to determine the success rates for anterior and posterior capsulorrhexis and intraocular lens (IOL) implantation in the bag for pediatric cataract surgery performed with the aid of a low-molecular-weight viscoelastic. Settings and Design: Nonrandomized observational study. Materials and Methods: Children less than 6 years of age who underwent cataract surgery with IOL implantation in the period May 2008–May 2009 were included. The surgeries were done by pediatric ophthalmology fellows. A standard procedure of anterior capsulorrhexis, lens aspiration with primary posterior capsulorrhexis, anterior vitrectomy, and IOL implantation was followed. Three parameters were studied: successful completion of anterior and posterior capsulorrhexis and IOL implantation in the bag. Results: 33 eyes of 28 children were studied. The success rate for completion was 66.7% and 88.2 % for anterior and posterior capsulorrhexis, respectively. IOL implantation in the bag was successful in 87.9%. Conclusions: 2% hydroxypropylmethylcellulose is a viable low-cost alternative to more expensive options similar to high-molecular-weight viscoelastics. This is of great relevance to hospitals in developing countries.

[Viscoelastic properties of acid-induced casein gel in a model system]

Nowadays, acid-induced milk protein gels are used extensively in the dairy industry and are the base of many food products. Therefore, a deeper fundamental understanding of the effects of process parameters and system components on the mechanisms of gel formation and final gel properties in real and model systems is important for researchers and industries. The present study was designed to investigate the effects of casein-to-whey protein ratio, incubation temperature, and heating temperature on viscoelasic properties of the final gel in a model system. Samples of solutions with different casein-to-whey protein ratios [2.1:0.9, 2.4:0.6 and 2.7:0.3] were prepared and refrigerated overnight. This was followed by heating the samples at different temperatures [70, 80, or 90°C] for 15 minutes using a water bath and cooling to incubation temperatures [25, 35 or 45 °C]. In the next step lucono-sigma-lactone was added and the samples were transferred to a rheometer. The gelation process was monitored by the time sweep oscillatory test. A second-order polynomial model was fitted to the experimental data and the optimum response was determined using the Minitab15 software. Incubation and heating temperatures influenced significantly [P<0.001 and P<0.01, respectively] the G'200 value [storage modulus value of the final gel measured 200 minutes after addition of GDL]. The casein-to-whey protein ratio had no significant influence on the G'200 value. Increasing the incubation temperature led to a decrease, whereas increasing the heating temperature led to an increase, in the G'200 value. The maximum value of G'200, 268/93 Pa, was obtained at the presence of 2.6152% [w/w] casein and at incubation and heating temperatures of 25 °C and 90 °C, respectively. Smaller quantities of casein and higher incubation and heating temperatures shortened the length of time required for gel formation. Finally, increased incubation temperatures and decreased heating temperatures led to increased the damping factor [tan sigma]. The effects of different process parameters on the viscoelastic properties of dairy gels can be determined and characterized by oscillatory rheometry. The findings of this study show that incubation temperature is the most effective factor, whereas casein-to-whey protein ratio has no significant effect on the final gel strength

Management of intraoperative miosis during pediatric cataract surgery using healon 5

We describe a technique for achieving pupillary dilatation in order to manage and counteract intraoperative miosis during pediatric cataract surgery using viscoadaptive viscoelastic [sodium hyaluronate 2.3%]. The technique of viscomydriasis was used in six eyes with pediatric cataracts with intraoperative pupillary miosis. Pupillary dilatation was achieved and maintained in all eyes throughout cataract surgery. All the surgical steps including anterior and posterior capsulorrhexis and aspiration were performed successfully. Viscomydriasis is a simple and effective technique for the management of intraoperative pupillary miosis during cataract surgery in pediatric eyes

Evaluation of Surgical Outcome after Cataract Surgery with Len Implantation Using air or Elastic to Maintain the Anterior Chamber

Introduction: Findings from specular microscope studies have demonstrated increased endothelial cell loss associated with the use of air for lens implantation. The objective of this study was to evaluate the surgical outcome after cataract surgery with lens implantation using air or viscoelastic to maintain the anterior chamber Design: Retrospective record analysis Subjects: Record cards of patients operated for cataract at Sakubva Eye Unit; Mutare; Zimbabwe in the period January - December 2002 Main outcome measures: Operative complications; post operative keratitis; presenting visual acuity at discharge; two and six weeks postoperatively. Results: Record cards of 315 patients were analysed; 207 (65.7) had lens implantation under air; 108 (34.3) had implantation under viscoelastic. Presenting visual acuity at discharge; two and six weeks postoperatively was better or equal to 6/18 in 36.7; 34.4and 52of patients implanted under air compared to 40.7; 35.6and 38.3of those implanted under viscoelastic. Post operative keratitis was observed in 14of patients implanted under air and 12of those implanted under viscoelastic. Vitreous loss was experienced by 1.9and 5.8of patients implanted under air and viscoelastic respectively.Conclusion: Despite reports of increased endothelial cell loss associated with use of air for lens implantation; this study finds no difference in surgical outcome between patients implanted posterior chamber lens under air or viscoelastic

Viscoexpression technique in manual small incision cataract surgery.

Viscoexpression method of nucleus delivery in manual small incision cataract surgery is described in this article. The practical modifications to the conventional technique in special situations are presented. Intraoperative and postoperative problems likely to be encountered and the steps to avoid them and tackle them effectively are discussed.

Intraocular pressure after phacoemulsification using hydroxypropyl methylcellulose and sodium hyaluronate as viscoelastics

Phacoemulsification and intraocular lens [IOL] implantation has resulted in early visual rehabilitation, increased wound stability and improved refractive results. Viscoelastic substances [VES] are important adjuncts in this type of surgery. Use of VES in phacoemulsification can be associated with adverse effects, the most common and potentially dangerous of which is the transient rise in intraocular pressure [IOP] in post-operative period. To evaluate the effects of viscoelastic substances on post-operative IOP after phacoemulsification with implantation of intraocular lens, a cross-sectional comparative, prospective study was conducted in the department of Ophthalmology, Combined Military Hospital, Peshawar, Pakistan, from October 2003 to March 2004. one hundred patients were randomized into two groups of 50 each. Phacoemulsification with implantation of intraocular lens was performed in all patients. 2% Hydroxypropyl Methylcelloulose [HPMC] was used in one group and 1% Sodium Hyaluronate [NaHa] was used in the other group. IOP was measured pre-operatively as well as 24 hours and 7 days post-operatively. There was no significant difference in the pre-operative intraocular pressure between the two groups [p=0.483]. Twenty four hours after surgery, the mean IOP increased by 2.84 +/- SD 2.12 mm Hg in 2% Hydroxypropyl Methylcellulose group and 4.54 +/- 2.07 mm Hg in 1% Sodium Hyaluronate group. The increase returned to near pre-operative levels in both the groups. Sodium Hyaluronate causes significantly higher increase in intraocular pressure in early post-operative period after cataract surgery in spite of maximum aspiration of viscoelastic substance from the eye following phacoemulsification surgery

Protective Effects of Viscoelastic Substances on air Bubble Damage During Phacoemulsification

PURPOSE: To determine whether viscoelastic materials are effective to protect the corneal endothelium from air bubble damage. METHODS: Human eye bank (n=12) and rabbit (n=22) eyes underwent a standardized phacoemulsification procedure with or without viscoelastic material [1% sodium hyaluronate (Healon(R)), 1.4% sodium hyaluronate (Healon GV(R)), 3% sodium hyaluronate with 4% chondroitin sulfate (Viscoat(R))]. The integrity of the endothelium was examined after the procedure with F-actin staining and scanning electron microscopy (SEM). RESULTS: In the phacoemulsification experiment without viscoelastic material, with Healon, and with Healon GV, the endothelium of both human and rabbit corneas had many areas of cell loss in a pattern consistent with air bubble damage. But with Viscoat, endothelial cells remained intact. CONCLUSIONS: We found that Viscoat was effective to protect the endothelium from air bubble damage. Viscoat seems to protect the endothelium by acting as a physical barrier.

Efficacy and Safety of Commerical Used Viscoelastics: Healon(R), Provisc(R), Viscorneal(R), Hyal 2000(R), Biolon(R), Viscoat(R)

Several different viscoelastic substances are widely used in many ophthalmologic fields. In our study, the efficacy and safety of the different kinds of viscoelastics -Healon(R), Provisc(R), Viscorenal(R), Hyal-2000(R), Viscoat(R) and Biolon(R)-was evaluated in undergoing phacoemulsification and posterior intraocular lens implantation, corneal transplantation and ocular trauma surgery. We evaluated and the facility of the injection the foreign materials during injection of viscoelastics through the microscopy. We measured the changes of intraocular pressure at the postoperative 1 day and corneal endothelial cell count at the postoperative 2 month. The mean endothelial cell loss after phacoemulsification and posterior intraocular lens implantation was 13.71% at postoperative 1 day and there was no significantly different among groups. The incidence of the foreign materials including air bubles in viscoelastics in the operating microscope was Provisc(R), Hyal 2000 Viscorneal(R), Biolon(R), Healon(R) in order. The mean incidence of the intraocular pressure above 25 mmHg after cataract surgery at postoperative 1 day was 3.94%and was Hyal 2000(R), Biolon(R), Viscorneal(R), Healon(R), Provisc(R) in order. The incidence of the additional use of the antiglaucoma drugs in keratoplasty patients was 76%in Healon(R) group, 26.7%in Viscoat(R) group, 69.2%in Provisc(R) group respectively. From the results of this report, we conclude that it is desirable to use the proper viscoelastics according to the chemical and physical properties in special situations, but there is no significant difference in the same viscoelastic substance.

The Evaluation of the Endothelial Cells after Cataract Extraction and IOL Insertion in Patients with Corneal Guttata

When the corneal endothelium is injured by intraocular surgery, corneal edema occurs above the threshold level. Preoperative examination of corneal endothelium is valuable in prediction the degree of transparency of the cornea. We conducted this study to elucidate what factors affect corneal endothelial cells in performing the cataract extraction and IOL insertion and what is necessary to minimize the corneal endothelial damage. We performed pacoemulsification and IOL insertion in guttata patients, and preoperative and postoperative endothelial examination was done by using specuar microscope and pachymeter. Although the mean of endothelial cell density was diminished from 1498.7cells/mm2 to 1301cells/mm2 after operation. visible edema was not detected by slit lamp examination and visual acuity was improved from 0.15 to 0.48. The older the patient`s age, the longer the time of phaceemulsification; as the ages of the patients are increased, postoperative corneal thicknesses were increased and postoperative endothelial cell densities were decreased. The endothelial cells were relatively well preserved after cataract operation in patients of preoperative diminished endothelial cells. We suggest that when performing the cataract operation in patients of decreased endothelial function, one must use appropriate large amount of viscoelastic substances, and minimize phacoemulsification power and time in as short operation time as possible by accurate surgical technique. We also believe that periodic postoperative endothelial examination is necessary in patients with decreased endothelial function.

Effect of the Viscoelastic Substance on Surgery of the Extraocular Muscles in Rabbit: 1. Histopathologic Study by a Light Microscope

We evaluated histopathologically the effect of the viscoelastic substance on surgery of the extraocular muscle in the 26 rabbits with 1. 6-2. 5kg of weight. The viscoelastic substances were 1% sodium hyaluronate(Healon) and 2% hydroxypropyl methylcellulose(Methocel), which were introduced between the extraocular muscle and its adjacent tissue on surgery. The rabbits were categorized by group 1(the rabbits with Healon), group 2(with Methocel), and group 3(with normal saline as control). These rabbits were enuclated at 3rd, 7th, 14th, 28th and 56th day following operations, and the eyes were fixed in 2.5% glutaraldehyde solution. The tissue was stained with hematoxylin-eosin and Masson's trichrome, and examined under a light microscope. The results were as follows: 1. In the first group(Healon), the tissue adhesion and degeneration of the muscle were milder than those of control(saline) group. 2. The changes in second group(Methocel) was milder than in the first group and more severe than in control group. 3. It is concluded that 2% Methocel can be used clinically in the surgery of the extraocular muscle.