台盼蓝与吲哚青绿在成熟期和过熟期白内障手术中的应用

目的：：观察台盼蓝与吲哚青绿在成熟期、过熟期白内障超声乳化手术中进行连续环形撕囊( continuous curvilineal capsulorrhexis, CCC)的作用及效果。方法：选取成熟期、过熟期白内障122例122眼,随机分为3组,台盼蓝染色组( A组)46例46眼,吲哚青绿染色组(B组)40例40眼,对照组(C组)36例36眼。染色组在手术中分别使用台盼蓝或吲哚青绿0.2mL注入前房,进行CCC。术中观察及对比连续环形撕囊成功率、晶状体后囊破裂及人工晶状体囊袋内植入情况。观察术后前房炎症反应,并与对照组进行观察分析。结果：台盼蓝染色组(A组)连续环形撕囊成功率、人工晶状体囊袋内植入率与对照组(C组)进行统计学分析有显著性差异(P<0.05)。吲哚青绿染色组(B组)人工晶状体囊袋内植入率与对照组(C组)进行统计学分析有显著性差异(P<0.05)。晶状体后囊破裂率三组间无显著性差异(P>0.05)。术后观察前房炎症反应三组间无明显差异。结论：应用台盼蓝或吲哚青绿对缺乏红色反光的成熟期、过熟期白内障进行晶状体囊膜染色后再行CCC,目前是一种安全可靠的技术,两者效果相当。手术中可以使连续环形撕囊顺利进行,提高了手术成功率。     

Anterior capsular staining with trypan blue for capsulorhexis in mature and hypermature cataracts. A preliminary study

PURPOSE: To study the efficacy and safety of 0.1% Trypan Blue dye to stain the anterior capsule for capsulorhexis in mature and hypermature cataracts. METHODS: This preliminary study included 25 eyes of 25 patients with a unilateral mature or hypermature cataract, including one case of traumatic mature cataract. In all these cases 0.2 ml of 0.1% trypan blue dye was used to stain the anterior capsule. The efficacy and safety of the dye was evaluated on the basis of intraoperative and postoperative observations. RESULTS: In all 25 eyes the capsulorhexis was completed. There was peripheral extension of the capsulorhexis in the eye with traumatic cataract and the stained edge of the anterior capsule helped identification and redirection of the capsulorhexis. Successful phacoemulsification with intraocular lens implantation was performed in all eyes. Adverse reactions related to the dye such as raised intraocular pressure, anterior chamber inflammation and endothelial damage were not observed in the immediate postoperative period or at the end of mean follow-up of 3 months. CONCLUSION: Trypan blue dye staining of the anterior capsule appears to be a very useful and safe technique that simplifies capsulorhexis in mature and hypermature cataracts.     

Phacoemulsification of white hypermature cataract.

PURPOSE: To evaluate the safety of phacoemulsification of white hypermature cataract, which is common in developing countries. SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. METHODS: In a teaching hospital setting, a prospective evaluation of phacoemulsification in 25 eyes of 25 consecutive patients with hypermature cataract was done. Patients with good pupil dilation, optimal endothelial cell count, and disease-free ocular and systemic status were included. High magnification, sodium hyaluronate, and a Utrata capsulorhexis forceps were used to perform continuous curvilinear capsulorhexis (CCC). The stop and chop technique was used for nuclear emulsification. A 5.5 mm optic allpoly(methyl methacrylate) intraocular lens (IOL) was implanted, and wound closure was sutureless. RESULTS: Successful CCC was performed in 23 of 25 cases. In 2 cases, the CCC edge extended toward the periphery and a Vannas scissors was used to achieve an even cut. No complications were seen during nuclear emulsification and IOL implantation. Eighty percent of the patients had a visual acuity of 20/40 or better on the first postoperative day. Five patients had significant corneal edema that resolved within 1 week in all cases. CONCLUSION: Phacoemulsification was successfully and safely performed in appropriately selected patients with white hypermature cataract.     

Laser-phakopuncture in the treatment of soft cataracts.

A new method of treating soft cataracts by laser irradiation is described ("laser-phakopuncture"). Rupture of the lens capsule can be produced by a strong laser pulse focused on the anterior surface of the lens. This is followed by gradual reabsorption of the lens substance (in much the same manner as with a conventional discission procedure). Pigment deposits on the capsule are usually necessary to ensure sufficient absorption of light energy at the target point. The laser beam can also be employed in a preliminary procedure to produce such pigmented spots, and to prepare the eye for a subsequent laser-phakopuncture. The method was first investigated experimentally on animal eyes. The so-called Q-switched lasers proved to be most effective in producing a tear in the capsule. It was then tried clinically in nine juvenile patients and reabsorption of the lens substance was the eventual result in all cases, although full visual acuity was achieved in only tow of them. These of lasers offers a completely new approach to the treatment of cataract without surgery.     

Removal of a dislocated hypermature lens from the posterior vitreous

Sodium hyaluronate can be used to manipulate a hypermature dislocated cataract from the posterior pole of the eye and stabilise it in the retropupillary area prior to its removal, intact, through a limbal incision.     

Assessing disability in the patient with cataracts.

Snellen chart visual acuity has been the gold standard to measure the preoperative indication of cataract surgery as well as the postoperative outcome. To a patient with cataracts, the disability goes beyond their loss of visual acuity. Glare disability has often been studied independently. Newer studies, however, show that there is more integration with clinical and nonclinical vision. For example, studies are looking at integrating unilateral versus bilateral procedures, type of cataract, type of procedure, the patient's daily needs, and the patient's state of mental and physical health. Questionnaires are being developed to bring into focus nonclinical issues of visual function and quality of life. Understanding the full spectrum of disability associated with visual impairment from cataracts can help clinicians improve their approach to treatment and rehabilitation of these patients.     

Glare sensitivity in early cataracts.

In a previous study significant glare sensitivity (using Vistech MCT8000) was found only in patients with posterior subcapsular cataracts (PSC) beyond the very early (LOCS II grade 1) stage. The aim of the present study was to evaluate glare sensitivity in patients with early cataracts. The brightness acuity tester (BAT) was used with the Pelli-Robson chart on 50 patients with early cataracts (LOCS II grade 1 or 2) and on 14 normal volunteers. Only age and PSC were found to be associated with change in contrast sensitivity at high glare. Eyes with grade 1 PSC were not significantly different from eyes with grade 0 PSC after adjusting for age. Eyes with grade 2 PSC had significant glare effect compared with eyes having grade 0 PSC. Thus, glare sensitivity is associated only with early (grade 2) PSC. Other tests still need to be developed to assess visual function changes in patients with early cortical and nuclear cataracts.     

Difficulties in the phaco-emulsification of soft senile cataracts.

Several difficulties arise when a surgeon embarks upon the Kelman-Phaco-Emulsification method of cataract extraction. The most common but yet the least expected are technical difficulties with a soft cataract. A step by step, illustrated method of avoiding the disasterous pitfalls is outlined in order to aid the novice or occasional surgeon using phaco-emulsification on the "ideal" candidates for this operation.     

Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts

The goal of this project was to determine the relative refractive index (RI) of the interior of multilamellar bodies (MLBs) compared to the adjacent cytoplasm within human nuclear fiber cells. MLBs have been characterized previously as 1–4 μm diameter spherical particles covered by multiple lipid bilayers surrounding a cytoplasmic core of variable density. Age-related nuclear cataracts have more MLBs than transparent donor lenses and were predicted to have high forward scattering according to Mie scattering theory, assuming different RIs for the MLB and cytoplasm. In this study quantitative values of relative RI were determined from specific MLBs in electron micrographs of thin sections and used to calculate new Mie scattering plots. Fresh lenses were Vibratome sectioned, immersion fixed and en bloc stained with osmium tetroxide and uranyl acetate, or uranyl acetate alone, prior to dehydration and embedding in epoxy or acrylic resins. Thin sections 70 nm thick were cut on a diamond knife and imaged without grid stains at 60 kV using a CCD camera on a transmission electron microscope (TEM). Integrated intensities in digital electron micrographs were related directly to protein density, which is linearly related to RI for a given substance. The RI of the MLB interior was calculated assuming an RI value of 1.42 for the cytoplasm from the literature. Calculated RI values for MLBs ranged from 1.35 to 1.53. Thus, some MLBs appeared to have interior protein densities similar to or less than the adjacent cytoplasm whereas others had significantly higher densities. The higher density MLBs occurred preferentially in older and more advanced cataracts suggesting a maturation process. The bilayer coats were more often observed in MLBs from transparent donors and early stage cataracts indicating that bilayer loss was part of the MLB maturation, producing large low-density spaces around dense MLB cores. These spaces were frequently observed in advanced cataracts from India as large low-density crescents and annular rings. Predicted scattering from Mie plots using particles with dense cores and low-density rims was higher than reported previously, although the most important factor was the relative RI, not the MLB coat or lack thereof. In conclusion, the measurements confirm the high protein density and RI of some MLB interiors compared to adjacent cytoplasm. This high RI ratio used in the Mie calculations suggests that for 2000 MLBs/mm³, about half that reported for early stage nuclear cataracts from the US, the forward scattering could be more than 30% of the incident light. Therefore, the extent of forward scattering and its influence on macular visual acuity could be important components of ophthalmological evaluations of cataract patients.     

Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts

The goal of this project was to determine the relative refractive index (RI) of the interior of multilamellar bodies (MLBs) compared to the adjacent cytoplasm within human nuclear fiber cells. MLBs have been characterized previously as 1–4 μm diameter spherical particles covered by multiple lipid bilayers surrounding a cytoplasmic core of variable density. Age-related nuclear cataracts have more MLBs than transparent donor lenses and were predicted to have high forward scattering according to Mie scattering theory, assuming different RIs for the MLB and cytoplasm. In this study quantitative values of relative RI were determined from specific MLBs in electron micrographs of thin sections and used to calculate new Mie scattering plots. Fresh lenses were Vibratome sectioned, immersion fixed and en bloc stained with osmium tetroxide and uranyl acetate, or uranyl acetate alone, prior to dehydration and embedding in epoxy or acrylic resins. Thin sections 70 nm thick were cut on a diamond knife and imaged without grid stains at 60 kV using a CCD camera on a transmission electron microscope (TEM). Integrated intensities in digital electron micrographs were related directly to protein density, which is linearly related to RI for a given substance. The RI of the MLB interior was calculated assuming an RI value of 1.42 for the cytoplasm from the literature. Calculated RI values for MLBs ranged from 1.35 to 1.53. Thus, some MLBs appeared to have interior protein densities similar to or less than the adjacent cytoplasm whereas others had significantly higher densities. The higher density MLBs occurred preferentially in older and more advanced cataracts suggesting a maturation process. The bilayer coats were more often observed in MLBs from transparent donors and early stage cataracts indicating that bilayer loss was part of the MLB maturation, producing large low-density spaces around dense MLB cores. These spaces were frequently observed in advanced cataracts from India as large low-density crescents and annular rings. Predicted scattering from Mie plots using particles with dense cores and low-density rims was higher than reported previously, although the most important factor was the relative RI, not the MLB coat or lack thereof. In conclusion, the measurements confirm the high protein density and RI of some MLB interiors compared to adjacent cytoplasm. This high RI ratio used in the Mie calculations suggests that for 2000 MLBs/mm³, about half that reported for early stage nuclear cataracts from the US, the forward scattering could be more than 30% of the incident light. Therefore, the extent of forward scattering and its influence on macular visual acuity could be important components of ophthalmological evaluations of cataract patients.     

Intraocular light scattering in age-related cataracts.

Intraocular light scattering was studied in 34 controls and 65 patients with cortical, nuclear, or posterior subcapsular cataracts by measuring forward scatter and backscatter. Forward scatter was measured by the psychophysical direct compensation method. Backscatter was determined with the Lens Opacity Meter of Interzeag. Contrast sensitivity loss caused by forward scatter was assessed with a glare tester (Vistech MCT 8000). Mean forward scatter was in the upper range for subcapsular cataracts compared to nuclear and cortical cataracts. Experimental results of the glare test (the contrast loss) deviated systematically from expected results based on measured forward scatter. Mean backscatter was largest for nuclear, intermediate for posterior subcapsular, and almost zero for cortical cataracts. Thus, each cataract has a characteristic mean ratio between forward scatter and backscatter. However, this ratio varied considerably among individuals, especially for cortical and posterior subcapsular cataracts. As a rule, forward scatter cannot be derived from backscatter (or the slit-lamp image).     

Crosslinkage theory of senile cataracts.

The theory of crosslinkage as a cause of aging of all living organic tissues has withstood the test of time. Nearly all the past theories of senile cataract formation contain elements involving a potent crosslinking agent. Therefore crosslinkage may now be recognized as the common denominator in past theories of senile cataracts. This paper proposes that crosslinkage is the mechanism for senile cataract formation.     

过熟期白内障小切口非超声乳化摘除术临床应用观察

目的 探讨过熟期白内障小切口非超声乳化摘除术的方法 和疗效.方法选择过熟期白内障45例（50只眼）,采用小切口非超声乳化摘除人工晶状体植入术式.结果 患者术后视力恢复快,4周后趋于稳定.人工晶状体植入位置良好,并发症发生少.结论 过熟期白内障的复明可采用小切口非超声乳化术摘除术治疗.