Repair in the rat lens after threshold ultraviolet radiation injury

PURPOSE: To investigate the development and recovery of lens damage after in vivo close-to-threshold exposure to ultraviolet B radiation. METHODS: One eye of young, female Sprague-Dawley rats was exposed to 5 kJ/m2 narrowband ultraviolet radiation (UVR) (lambda(max) = 302 nm) for 15 minutes. Groups of rats were killed 1, 7, and 56 days after exposure. The structure of the exposed and nonexposed lenses was examined with light microscopy, scanning electron microscopy, transmission electron microscopy, freeze-fracture, fluorescent membrane staining, and Fourier transform analysis. RESULTS: One day after UVR exposure the lens surface had flakelike opacities. Seven days after exposure, the lens surface appeared opaque and corrugated, and the equatorial cortex had small opacities. At 56 days postexposure, the surface and equator appeared clear, but the cortex had a subtle shell-shaped opacity. At 1 day postexposure, apoptotic cell death occurred in the lens epithelium, but the cortical fibers were normal. At 7 days postexposure, the epithelium and the fibers between the 10th and 40th growth shell below the capsule contained extracellular spaces of different sizes. After 56 days, the epithelial layer appeared normal, and the extracellular spaces had disappeared; but abnormal fibers were found between the 60th and 100th growth shell below the capsule. Fibers above and below the damaged growth shells appeared fully normal. CONCLUSIONS: A close-to-threshold dose of UVR causes cataract, which is largely reversible. The UVR exposure leads to apoptosis in the lens epithelium, and after a latency period of several days, lens fibers are abnormal. Extracellular spaces develop in the epithelium and fibers. Within several weeks after exposure, the epithelium fully recovers and new fibers develop normally. The originally affected fibers are repaired. However, this repair is incomplete, leaving a small zone of enhanced light scattering in the equatorial cortex.     

Morphology of the cataract in albino mutant quails (Coturnix coturnix japonica)

Morphological changes in cataractous albino quail lens were studied by light microscopy. In some animals, a pin-head opacity in the lens could first be detected with the naked eye 2 months after hatching. Faint anterior or posterior cortical opacity was observed in many lenses at 3 months of age. Most lenses had turned opaque 12 months after hatching. Lens dimensions were markedly enlarged at 6 months of age. Vacuoles were present in the posterior surface just beneath the capsule and equatorial epithelium, before the cells became degenerative. Many swollen lens fibers and abnormally migrated cells were observed in the posterior cortical region. The lens was covered with several layers of epithelioid cells in the mature cataract.     

Response of the lens of the galactose-fed rat to YAG laser-induced injury

Many investigations have focussed on the response of normal lenses to injury, but almost no attention in this regard has been given to the response of cataractous lenses. We addressed this subject, particularly in regard to cell proliferation, using 'cataractous' lenses from rats fed on a galactose-rich diet. Five days after initiation of the 50% D-galactose diet, the anterior aspects of the lenses of these animals were injured by Nd-YAG laser. For up to 5 additional days, the rats were maintained on a 25% D-galactose diet. Similarly injured, control animals were fed on 100% Purina laboratory chow throughout the experimental period. The response of the lenses to injury was assessed by gross examination and by light microscopic examination of paraffin sections and epithelial whole-mounts. By the second day post-injury, the anterior aspect of some of the lenses from galactose-fed rats was characterized by a band of darkly staining structures. Although the average number of mitotic figures of lenses from galactose-fed (GF) rats had increased by 2 days after injury, it still remained below that of injured lenses from normally fed rats. After 5 days, some of the eyes of galactose-fed rats were greatly swollen. At both 2 days and 5 days after injury, lenses of GF rats tended to be characterized by a greatly proliferated epithelium, destruction of lens fibers, and loss of cortical material. Responses of lenses from normally fed rats were far less dramatic. The results suggest that, in the case of lenses made cataractous by a galactose-rich diet, injury is more deleterious, and the response of epithelial cells more intense, than in normal lenses.     

Disruption of the Sparc locus in mice alters the differentiation of lenticular epithelial cells and leads to cataract formation

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein that regulates cellular adhesion and proliferation. In this report, we show that SPARC protein is restricted to epithelial cells of the murine lens and ends abruptly at the equatorial bow region where lens fiber differentiation begins. SPARC protein was not detected in the lens capsule or in differentiated lens fibers. SPARC-null mice developed cataracts at approximately 3-4 months after birth, at which time posterior subcapsular opacities were observed by slit lamp ophthalmoscopy. Histological analyses of ocular sections from 3-month old animals revealed several microscopic abnormalities present in the SPARC-null mice but absent from the wild-type animals. Fiber cell elongation was incomplete posteriorly and resulted in displacement of the lenticular nucleus to the posterior of the lens. Nuclear debris was present in the posterior subcapsular region of the lens, an indication of the abnormal migration and elongation of either fetal or anterior epithelial cells, and the bow region was disrupted and vacuolated. In the anterior lens, the capsule appeared to be thickened and was lined by atypical, plump cuboidal epithelium. Moreover, anterior cortical fibers were swollen. Polyacrylamide gel electrophoresis of the epithelial, cortical and nuclear fractions of wild-type and SPARC-null lenses indicated no significant differences among the alpha-, beta-, and gamma-crystallins. Expression of alphaB-crystallin appeared similar in fiber cells of wild-type and SPARC-null lenses, although the distribution of alphaB-crystallin was asymmetric in SPARC-null lenses as a result of abnormal lens fiber differentiation. No evidence of atypical extracellular matrix deposition in areas other than the capsule was detected in wild-type or SPARC-null lens at 3 months of age. We conclude that the disruption of the Sparc locus in mice results in the alteration of two fundamental processes of lens development: differentiation of epithelial cells and maturation of fiber cells.     

Lenses of SPARC-null mice exhibit an abnormal cell surface-basement membrane interface

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein involved in cell-matrix interactions. We have shown previously that mice deficient in SPARC develop posterior cortical cataract early in life that progresses to a mature opacity and capsule rupture. To evaluate the primary effects of SPARC deficiency in the lens, we examined the lenses of SPARC-null and wild-type mice by electron microscopy and immunohistochemistry to investigate whether ultrastructural abnormalities occur at the basement membrane (capsule)-lens cell interface in SPARC-null mice. The most notable feature in the lenses of SPARC-null mice, relative to wild-type animals, was the modification of the basal surface of the lens epithelial and fiber cells at the basement membrane (capsule) interface. Electron microscopy revealed numerous filopodial projections of the basal surface of the lens epithelial and fiber cells into the extracellular matrix of the anterior, posterior, and equatorial regions of the lens capsule. In 1 week old precataractous lenses, basal invasive filopodia projecting into the capsule were small and infrequent. Both the size and frequency of these filopodia increased in precataractous 3-4 week old lenses and were prominent in the cataractous 5-6 week old lenses. By rhodamine-phalloidin labeling, we confirmed the presence of basal invasive filopodia projecting into the lens capsule and demonstrated that the projections contained actin filaments. In contrast to the obvious abnormal projections at the interface between the basal surface of the lens epithelial and fiber cells and the lens capsule, the apical and lateral plasma membranes of lens epithelial cells and lens fibers in SPARC-null mice were as smooth as those of wild-type mice. We conclude that the absence of SPARC in the murine lens is associated with a filopodial protrusion of the basal surface of the lens epithelium and differentiating fiber cells into the lens capsule. The altered structures appear prior to the opacification of the lens in the SPARC-null model. These observations are consistent with one or more functions previously proposed for SPARC as a modulator of cell shape and cell-matrix interactions.     

Regional analyses of the reversal process in the neonatal galactose cataract

Reversal of the galactose cataract in neonatal rat lenses involves a decrease in lenticular galactitol, a recovery of existing fiber contour and interdigitation, and a production of new fibers. The onset of neonatal cataractogenesis appeared at 7 days when the young were nursed by mothers placed on a 50% galactose diet at the time of delivery. On the 7th day, the mothers were returned to a normal diet and reversal of the neonatal cataract was monitored for the remainder of the nursing period. After 5 days on a normal diet, cataract reversal was incomplete; this is evidenced by an abnormal fiber contour with decreased number of interdigitating processes, the presence of galactitol and decreased lens size. Fiber alterations were most pronounced in the anterior superficial cortex (0–200 μm from the capsule). As the reversal period progressed for an additional 8 days, lenticular galactitol declined and normalization of anterior superficial and supranuclear cortical fibers occurred.Growth of the normal and reversal lenses was compared by determining the number of fiber lamellae produced per day. As new fibers were formed, by the anterior lens epithelium, the radius of the lenses increased with time; the increase in lens radius and the average fiber width were measured for the juvenile lenses (12–63 days) and the reversal lenses (12–20 days). The number of fiber lamellae produced during each growth period was calculated. Normal lens growth was a consistent 1 fiber lamella/day. During the reversal period, lens growth was increased with respect to normal; the source of the rapid generation of new fibers may be the differentiation of equatorial, multilayered epithelial cells which were induced by the galactose feeding.     

In vitro differentiation of cells of the lens epithelium of human fetus

Cells dissociated from fetal human lens epithelium of approximately 9 and 15 weeks after conception were cultured as monolayers in vitro. About 25 days after inoculation, a number of transparent piles of highly swollen cells appeared on the epithelial cell sheet. Ultra-structurally, these piles are assemblages of elongated cells with typical profiles of mature lens fibers. Gamma-crystallin which is undetectable in the lens epithelium is immunologically detected in late stage cultures containing these piles. Thus, it is concluded that cells of the human fetal lens epithelium can differentiate into lens fibers in monolayer culture.     

Formation of after-cataract by regeneration of human and rabbit lens epithelium in tissue culture

Regeneration of lens epithelium on the lens capsule was studied in tissue culture. The entire capsule with attached epithelium was taken from rabbit lenses and from human lenses with cataract. Generally, the epithelium grew in a monolayer but multilayered masses of cells were also seen. Most lens fibers degenerated during the first days and formed spherical membrane enclosed vesicles containing cytoplasm but no nuclei. The lens fiber remnants, together with regenerating epithelium, created structures that were similar in many ways to the clinical appearance of after-cataract.     

Morphological study on rupture of posterior capsule in RLC mouse lens

Purpose: To clarify the causative factor underlying rupture of the posterior capsule of the RLC mouse lens as a recessive trait around the 50th postnatal day. Methods: The lenses of the RLC mouse were removed in the period from birth to 50th postnatal day. Some specimens were observed by light microscopy and transmission and scanning electron microscopy. Others were examined as flat preparations of the lens epithelium. Results: There was an abnormal arrangement of lens fibers at the newborn stage, and lens fibers of the perinuclear zone ended almost vertical in relation to the posterior capsule. Consequently, the posterior suture was not formed in this mouse lens. On the 10th postnatal day, the ends of the lens fibers that terminated in the posterior capsule became swollen, and the posterior capsule at the posterior polar region became thin. On the 20th day, the area of swollen fibers was so large at the center of the posterior capsule that a vacuolated area was observed under the dissecting microscope. On the 30th day, the posterior cortical fibers in this area showed marked swelling, and the posterior capsule became extremely thin. On the 40th day, the anterior cortex became unusually thick, and the lens nucleus was dislocated towards the posterior capsule. On the 50th day, the posterior capsule ruptured. At this time the lens fibers from the perinuclear zone constituted the central area of rupture, and the cortical fibers from the equator formed the protruded area outside the lens. Conclusion: The findings revealed that the RLC mouse lens has an abnormal lens fiber arrangement from the early period of lens development, that the lens fibers from the perinuclear zone cause swelling without forming the posterior suture, and that the thin capsule is ruptured by pushing out of the nucleus by thickening of the anterior cortex. Received: 14 March 2000 Revised: 16 May 2000 Accepted: 25 May 2000     

Morphological and cell volume changes in the rat lens during the formation of radiation cataracts

Earlier studies in our laboratory showed that 24 hr after X-irradiation, epithelial cells of early postnatal rat lenses increased in volume. Three days after X-irradiation, the underlying lens fibers increased in volume. This finding suggested a correlation between damage to epithelial cell volume regulation and subsequent fiber cell swelling. To test this hypothesis 4-week-old rat lenses were three-dimensionally reconstructed to determine average cell volumes of specific lens regions and wet weights of whole lenses were measured during radiation cataract formation. In addition, the differentiation of epithelial cells into lens fibers was monitored by autoradiography. Four-week-old Sprague-Dawley rats were injected with [3H]-thymidine and, 24 hr later, their eyes were irradiated with either 400 or 1200 rad. Lenses were examined with a slit lamp and cataracts were graded on a scale of 1+ to 4+. Animals were killed 24 hr and 3, 5, 15 and 30 weeks after exposure. Lenses were serially sectioned at 0.75 micron and epithelial, equatorial and cortical fiber cell volumes were determined. Rats exposed to 400 or 1200 rad developed 0.5-1.5+ or 2.5-3.0+ cataracts, respectively, 10-16 weeks after X-irradiation. Epithelial and equatorial cells of both groups did not significantly increase in volume during this period. Three weeks after irradiation with 1200 rad cortical fibers were disorganized and had increased volume. By 5 and 15 weeks, cortical fibers had more normal cell volumes, although their morphology remained grossly altered. Cortical fiber volume of lenses irradiated with 400 rad were not significantly different from control lenses throughout the experimental period. By 15 weeks lenses irradiated with 400 rad showed subtle changes in morphology. Wet weight determinations indicated that the localized increase in cortical fiber volume did not result in an increase in the wet weight of the entire lens. Autoradiography showed that affected fibers had been epithelial cells at the time of X-irradiation. These results provide additional evidence that disturbances in fiber differentiation are involved with cataract formation, but do not support the initial hypothesis that a disturbance in epithelial cell volume regulation leads to fiber cell swelling. Earlier results suggesting defects in lens epithelial volume regulation in radiation cataract formation may have been complicated by ocular inflammation.     

Incidence of posterior capsule opacification in eyes with and without posterior chamber intraocular lenses

The incidence of posterior capsule opacification after extracapsular cataract extraction was significantly lower in eyes implanted with posterior chamber intraocular lenses than in nonimplanted eyes. The number of loops fixated in the bag was significantly smaller in the eyes that became opacified than in those that did not. These findings suggest that the posterior chamber lens suppresses the two processes that lead to opacification: the development of a ring-shaped opacity at the site of contact between the anterior capsule rim and the posterior capsule and the migration of lens epithelial cells toward the center of the capsule. These suppressive effects were greater when the posterior chamber lens was fixated in the bag.     

Optical constancy of the chick lens during pre- and post-hatching ocular development

Embryonic and post-embryonic development of the ocular lens is associated with the continual production of new secondary lens fibers by the mitotic activity of equatorial epithelial cells. This continual development affects lens size and shape and refractive index distribution. Study of embryonic lens optical function has been largely ignored. The optical characteristics of the developing chick lens, including paraxial and eccentric focal lengths, were measured during the embryonic period of development and up to 15 days after hatching. Measurements were made with an automated scanning laser system in which the video image of a helium-neon laser beam refracted by an excised lens in solution is digitized. Focal length is measured for beams moving in small steps on either side of that center. Measurements were made on excised lenses as well as with the lens in situ within the anterior segment of the eye. The results, collected from a study of a total of 80 lenses, indicates that embryo lenses at 6-7 days of incubation have long and very variable focal lengths. At the tenth embryo day, focal length drops by more than one-half and focal variations, between lenses and for different beam positions within a single lens, is reduced. Further measures for 14- and 17-day embryo lenses, as well as for lenses from hatchling and 5-, 10- and 15-day-old chicks, indicate that there is little change in focal length, either paraxially or for eccentric beam positions.(ABSTRACT TRUNCATED AT 250 WORDS)     

大鼠半乳糖性白内障晶状体上皮细胞的病理变化

目的　探讨半乳糖性白内障大鼠晶状体上皮细胞的改变。方法　２４只ＳＤ雌性大鼠,分为正常对照组和白内障组,每组１２只。白内障组大鼠用半乳糖饲料喂养,正常对照组大鼠用普通颗粒饲料喂养。裂隙灯显微镜下观察大鼠晶状体混浊程度变化,观察至３０ｄ处死大鼠后取晶状体,在光镜和电镜下观察晶状体病理组织和超微结构改变。结果　观察至３０ｄ时,正常对照组大鼠晶状体保持透明,白内障组大鼠９眼（３７．５％）出现均一的皮质性混浊,１５眼（６２．５％）出现核混浊。白内障组光镜下可见晶状体皮质和核部大量纤维细胞水肿、崩解,前囊膜下及后囊膜下出现纤维细胞样的有核细胞堆积;透射电镜下可见晶状体上皮细胞变性、增生并突破晶状体上皮层向浅层皮质移行。结论　半乳糖性白内障不仅有晶状体纤维细胞水肿及结构破坏,还存在晶状体上皮细胞的异常增生、分化和移行。     

Fibrillopathy in a pseudophakic eye. Production of fibrils by remnants of the lens capsule.

The ultrastructure of the lens capsule remnants in an eye with known fibrillopathy (pseudoexfoliation/exfoliation syndrome) subjected to an extracapsular cataract extraction (ECCE) and lens implantation 11 months earlier was examined. Lens epithelial changes typical in lenses with fibrillopathy were observed. The well-known fibrils radiated from pits in the lens epithelial cells, forming a deep layer in the lens capsule and the Busacca bushes on the capsule surface. It thus appears that the production of fibrillar material from lens epithelium may continue after ECCE and implantation of an intraocular lens. A possible connection between intracellular and extracellular fibrils was noticed.     

Src-家族酪氨酸激酶对皮质性白内障晶状体中缝隙连接蛋白的影响

目的探讨抑制Src-家族酪氨酸激酶的异常激活在皮质性白内障的形成中对晶状体缝隙连接蛋白43（Cx43）的影响。方法分离10d的鸡胚胎全晶状体并在M199培养液中培养10d为对照组;加入0.1nmol/LSFK特异性抑制剂PP1作为PP1组。观察2组晶状体的混浊程度、计算晶状体的混浊面积百分比。对培养1、5、10d的晶状体细胞进行WGA、DAPI免疫荧光染色,观察晶状体组织学改变及Cx43分布和表达量的变化。在晶状体前囊膜上进行Lucifer Yellow染料负荷试验,测量染料弥散距离,评价缝隙连接的功能。结果对照组晶状体的混浊面积百分比在4d、10d分别为26%和50%,而PP1组为20%和14%（P〈0.01）。培养5d、10d对照组晶状体上皮细胞（LECs）出现死亡,Cx43主要在LECs间表达;PP1组LECs死亡明显减少,Cx43的表达在上皮与纤维的交界面明显增强。在培养后1d、10d,对照组染料弥散距离与PP1组比较差异有统计学意义（P〈0.01）。结论在体外培养鸡胚晶状体模型中,PP1可能通过保护Cx43缝隙连接功能以保持晶状体上皮组织结构正常,减缓皮质性白内障的发生。     

Vertical movement of epithelial basal cells toward the corneal surface during use of extended-wear contact lenses

PURPOSE: To study the effects of extended contact lens wear (EW) on the movement of basal epithelial cells toward the corneal surface. METHODS: Rabbits (n = 32) were injected with 5-bromo-2-deoxyuridine (BrdU) to label a group of proliferating basal epithelial cells, and, 24 hours later, one randomly chosen eye was fitted with a low- or medium-oxygen-transmissible (Dk/t) rigid gas permeable (RGP) contact lens, while the other eye served as the control (n = 28). Four rabbits were not fitted with any contact lens. Rabbits were euthanatized at different time points and the corneal epithelium was immunocytochemically stained for BrdU and/or Ki-67 and counterstained with propidium iodide or Syto 59. Corneal flatmount tissues were examined three dimensionally under a laser confocal microscope and the location of each BrdU-labeled cell in the corneal epithelium (basal or suprabasal) was determined. RESULTS: Four days after injection of BrdU, both low- (P < 0.001) and medium-Dk/t RGP (P < 0.001) lens groups showed significantly more BrdU-labeled cells in the basal cell layer than in the control eyes. Six days after injection of BrdU, a small percentage of BrdU-labeled cells (<0.5%) were Ki-67 positive. CONCLUSIONS: Within 6 days, the majority (80%) of BrdU-labeled basal cells became terminally differentiated and rarely divided secondarily in the central epithelium. Short-term use of low- and medium-Dk/t RGP EW contact lenses slows the normal movement of basal epithelial cells toward the surface in the central cornea. This is consistent with known EW-lens-induced decreases in corneal epithelial basal cell proliferation and surface cell exfoliation. Overall, the data suggest that EW lenses significantly inhibit the normal homeostatic turnover rate of the corneal epithelium.     

In vitro model for the study of human posterior capsule opacification

PURPOSE: To develop and evaluate a model for the organ culture of human lens capsules that reduces problems inherent in preexisting models for the study of in vitro posterior capsule opacification (PCO). METHODS: Human lenses (N = 110) were isolated from donor eyes and supported externally within a lens holder system by medical-grade cyanoacrylate glue, allowing visualization of the entire capsular bag. After capsulorhexis and lens extraction were performed, the capsule specimens were maintained at physiological conditions for up to 4 weeks. The area of lens epithelial cell (LEC) coverage over the posterior capsule surface was determined objectively on a daily basis using a graticule. Lens epithelial cell behavior was correlated with clinical data and other in vitro PCO models. RESULTS: Cyanoacrylate glue did not appear to be toxic to LECs at the concentration used. The amount of viable epithelium after nuclear extraction was dependent on the age and postmortem time of the specimen. Viable LEC cultures were obtained from eyes up to 9 days postmortem. The time from death to culture or from enucleation to culture did not influence LEC viability if it was fewer than 5 days. The LEC proliferation rates and confluence times were age dependent and correlated closely between pairs of eyes. CONCLUSIONS: Results show that the lens holder model is a more physiological method for supporting the capsule and is a robust, reproducible system for the study of LEC migration and proliferation. It allows visualization within the entire capsular bag. Intraocular lenses can be implanted in this system in a way that more closely resembles the in vivo scenario. This model can be used to evaluate therapeutic measures to prevent PCO.     

The ultrastructure of the deep layer of the lens capsule in fibrillopathia epitheliocapsularis (FEC), so-called senile exfoliation or pseudoexfoliation. A scanning electron microscopic study

The epithelial surface of the lens capsule and the capsular surface of the epithelium have been studied in six cataractous lenses from persons with fibrillopathia epitheliocapsularis (FEC) or so-called senile exfoliation or pseudoexfoliation by scanning electron microscopy. Five of the lenses came from eyes with capsular glaucoma. Three senile cataractous lenses have been used as controls and two of the control lenses came from eyes with simple glaucoma. The investigation revealed round discoid plaques closely adherent to the capsule. The plaque surfaces had numerous smooth tentacle-like projections and matching pits in the underlying epithelium. These plaques were only found in FEC lenses and corresponded both in size and location to the structure known as the deep or amorphous layer of the lens capsule. The findings indicate that the epithelial cells are the source of origin.     

Effect of inhibition of the glutathione redox cycle on the ultrastructure of peroxide-treated rabbit epithelial cells

Our previous studies have shown that exposure of cultured rabbit lenses to physiological levels of hydrogen peroxide, following inhibition of the glutathione redox cycle, leads to the formation of distinct vacuoles in the anterior region of the lens at the germinative zone between the epithelium and lens fibers. In the present study the ultrastructure of H2O2-induced membrane damage in the intact lens and in cultured lens epithelial cells was examined by scanning and transmission electron microscopy (SEM and TEM), following the inhibition of glutathione reductase with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Lenses treated with BCNU/H2O2 exhibited swollen epithelial cells which were observed only above the peroxide-induced vacuoles. The apical surface of the swollen cells had membrane blebs which protruded into the underlying vacuolar space. The appearance of the blebs coincided with a change in the organization of the layer of microfilaments which is normally associated with the apical surface of the cell. Cultured lens epithelial cells treated with BCNU/H2O2 showed membrane blebs which increased in size and number with the duration of exposure. Initially, the blebs were seen only on certain regions of the cell surface with other regions appearing normal. TEM revealed a disorganization of microfilaments in the BCNU/H2O2 treated cells. Neither BCNU nor H2O2 alone affected the morphology of intact lenses or of cultured lens epithelial cells. In culture, isolated lens epithelial cells exposed to BCNU/H2O2 were more susceptible to damage than contiguous cells. While the exact mechanism by which H2O2-induced damage leads to bleb formation on the cell surface is not known, the inability of the cells to detoxify H2O2 due to the inhibition of glutathione reductase results in the disturbance of membrane cytoskeleton and a focal weakening of the cell surface. These results indicate a correlation between the active glutathione redox cycle in lens epithelium and maintenance of normal cytoskeletal protein organization.     

Nd:YAG laser posterior capsulotomy: a clinical study

As a postoperative complication to cataract surgery [extracapsular extraction (ECCE), phacoemulsification (KPE)], the posterior capsule (PC) of the lens often becomes opacified with plaque, Elschnig's pearls, or fibrotic bands, resulting in decreased visual acuity (VA). A Q-switched Nd:YAG ophthalmic laser was used to perform noninvasive micropuncturing of the posterior capsule. Two hundred thirteen patients (195 with existing intraocular lenses) underwent laser capsulotomy within a 14-month clinical study. These patients were followed over a 6-month postcapsulotomy period. Findings indicate excellent restored VA with minimal ocular complications.