Intraoperative miotics and posterior capsular opacification following phacoemulsification with intraocular lens insertion

BACKGROUND AND OBJECTIVES: Posterior capsular opacification (PCO) is a frequent complication following phacoemulsification with intraocular lens (IOL) implantation. A series of consecutive patients receiving capsular bag-fixated, silicone IOL implants were assessed for both incidence of PCO and the administration of intraoperative miotics. PATIENTS AND METHODS: During a 5-year period, 477 consecutive eyes were retrospectively evaluated. Surgeries were grouped according to intraoperative miotic agent: 0.01% carbachol or 1.0% acetylcholine. Patients receiving no miotic drug served as a control group. Yttrium-aluminum-garnet (YAG) laser posterior capsulotomy was performed on patients with clinically significant PCO. RESULTS: The percentage of eyes requiring YAG laser capsulotomy was similar for the three groups: 21.6% (25 of 91) for the carbachol group, 18.4% (14 of 62) for the acetylcholine group, and 18.6% (53 of 232) for the control group. A chi-squared analysis indicated that the difference among the groups was not statistically significant. The three groups also had similar average follow-up times between surgery and YAG capsulotomy (carbachol group = 52.2 weeks, acetylcholine group = 47.5 weeks, and control group = 48.3 weeks). CONCLUSION: Intraocular miotics do not increase the incidence of PCO.     

Photodegradation of furosemide solutions

PURPOSE: To evaluate the therapeutic effect of combined argon and Nd: YAG laser peripheral iridectomy. METHODS: 151 cases (200 eyes) of primary angle-closure glaucoma and combined glaucoma were treated by combined procedure. Argon laser was the first used to create partial iridectomy in 2/3-3/4 thickness without penetrating pigmented epithelium, and then Nd: YAG laser was required to complete a patent iridectomy. RESULTS: A successful iridectomy was achieved in all patients independent of any type of irides (100%). Iris penetration rate in one session presented in 95.0%. Complications appeared to be less common in our patients: iris bleeding was only seen in 5.0% cases; the postoperative inflammation was mild; corneal burns, localized lenticular opacities and closure of iridectomies were less frequent. The follow-up ranged from 3m to 6.5 years. The success rate in controlling IOP with/without medications were 99.0% except 2 eye failure. No attack occurred in 129 eyes with prophylactic laser therapy during the periods of follow-up. CONCLUSION: Combined procedure had much more advantage over either the argon or Nd: YAG laser iridectomy. It tended to be more preferable for Asian patients with heavily pigmented and thick irides.     

Nd:YAG laser removal of pupillary membranes developed after ECCE with PC-IOL implantation

PURPOSE: To define the frequency of development of pupillary membranes after ECCE with PC-IOL implantation, and to remove the pupillary membranes using the Nd:YAG laser. METHODS: From 400 patients who had undergone ECCE and were free from local or systemic illness affecting the blood-ocular barrier, 20 eyes developed pupillary membranes Nd:YAG laser was used to remove these pupillary membranes. RESULTS: The frequency of pupillary membranes was found to be 5% (9.8% in pex eyes and 3.3% to the non-pex eyes). Visual acuity improved in 17 eyes by 2 to 5 Snellen lines. No serious complications were observed, endothelium inclusive. CONCLUSION: Pseudoexfoliation might play a significant role in the development of postoperative pupillary membranes which could be successfully treated with the use of Nd:YAG laser. The safety of the procedure has to be evaluated in relation to the corneal endothelium damage in long-term.     

Clear lensectomy and implantation of a low-power posterior chamber intraocular lens for correction of high myopia: a four-year follow-up

PURPOSE: To evaluate the 4-year postoperative outcomes of patients who are highly myopic who underwent clear lensectomy via phacoemulsification and low power posterior chamber intraocular lens implantation. METHODS: The authors performed surgery in 52 eyes of 30 patients in which prophylactic retinal treatment, clear lensectomy, and posterior chamber intraocular lens implantation were used to treat high myopia of 12 diopters (D) or greater. A total of 49 eyes of 28 patients were evaluated at the 4-year postoperative timeframe. Visual acuity, complications, and refractive stability were assessed. RESULTS: The incidence of retinal detachment through 4 years was 1.9%. No new macular complications were observed. Two patients had posterior vitreous detachment without clinical impact between 1 and 4 years after surgery. The incidence of neodymium:YAG (Nd:YAG) capsulotomy was 36.7%. The mean postoperative spherical equivalent was -0.92 D. Four patients had a myopic shift of 0.50 D to 1.00 D from the 1- to 4-year timeframe. Corrected visual acuity of 20/40 or better was achieved in 82% of eyes that had undergone Nd:YAG capsulotomy versus 56% of untreated eyes. Uncorrected visual acuity of 20/100 or better was achieved in 82% of eyes treated with the Nd:YAG laser versus 62% of untreated eyes. CONCLUSION: Visual acuity and refractive outcomes with clear lensectomy are favorable. Retinal detachment remains the major concern of this procedure. Continuous follow-up of these patients is necessary.     

Elschnig pearl formation along the posterior capsulotomy margin after neodymium:YAG capsulotomy

PURPOSE: To determine the incidence of Elschnig pearl formation along the capsulotomy margin (string of pearls) after neodymium:YAG (Nd:YAG) laser posterior capsulotomy and to elucidate its clinical features, predisposing factors, effect on visual function, and association with additional capsulotomy. SETTING: Keio University Hospital, Tokyo, Japan. METHODS: The records of 418 eyes that had had Nd:YAG posterior capsulotomy after cataract surgery were retrospectively reviewed. Of those, 315 were excluded for short follow-up (fewer than 12 months) or insufficient clinical examination data. In the remaining 103 eyes, the incidence of string of pearls was calculated, and its clinical features, predisposing factors, effect on visual function, and correlation with additional capsulotomy were evaluated. RESULTS: String of pearls was identified in 49 eyes (47.6%); 37 (75.5%) developed pearls within 1 year after Nd:YAG capsulotomy. The incidence was significantly higher in patients having intraocular lens implantation and continuous curvilinear capsulorhexis (CCC) than in those without (95.9 versus 61.1% and 97.9 versus 55.6%, respectively). No significant differences were found in patient age and sex, total Nd:YAG energy, and the presence of diabetes mellitus or high myopia. String of pearls caused visual disturbances in 17 eyes (34.7%). The rate of repeat capsulotomy was higher in patients with string of pearls than in those without (36.7 and 9.3%, respectively). CONCLUSIONS: String of pearls formation was a common and significant complication after Nd:YAG posterior capsulotomy. Intraocular lens implantation and CCC may promote its formation.     

Increased cataract rate and characteristics of Nd:YAG laser capsulotomy in retinitis pigmentosa

BACKGROUND: Retinitis pigmentosa (RP) is associated with the development of a posterior subcapsular cataract (PSC). The development of posterior capsule opacification (PCO) after cataract surgery and a decrease of central visual acuity is sometimes misinterpreted by the patients as natural course of RP. Therefore, therapeutic intervention is often delayed. PATIENTS AND METHODS: In a retrospective study (part 1) the incidence of PCO was evaluated in a group of 26 RP patients who underwent cataract surgery and IOL implantation. In a prospective analyse (part 2) PCO was quantified in 13 RP patients using the standardized photographic technique and image analysis system introduced by Tetz et al. Matched pairs were formed with a control group of 13 patients without retinal disease who matched the RP group in terms of age distribution and postoperative follow-up time. In part 3 the parameters of Nd:YAG laser capsulotomy in 12 RP patients and 14 controls were evaluated. RESULTS: Part 1: The cumulative PCO rate in RP at the end of the first postoperative year was 14.6%, 26.8% in the second, 53.7% in the third and 70.7% after the third year. Nd:YAG laser capsulotomy was performed in 70% of eyes (after 18.4 +/- 14.7 months). In eyes with significant PCO development 70% had PSC preoperatively, while in eyes without PCO formation only 41.7% showed PSC. Part 2: The matched pairs analysis showed a significantly higher PCO value for RP patients (2.11 +/- 1.42) than for the control group (0.89 +/- 0.72) (P = 0.038). Part 3: Average Nd:YAG laser energy levels were 12.8 +/- 11.2 MJ (RP) and 7.6 +/- 6.7 MJ (control). Some 25% of RP patients required further laser treatment of regrown secondary cataract. CONCLUSIONS: Patients with RP showed a significantly higher incidence and density of PCO. Whether RP-specific pathomechanisms are responsible for this needs further investigation.     

Extracapsular cataract extraction in diabetic eyes. The role of YAG laser capsulotomy

Cataract surgery may exacerbate preexisting diabetic retinopathy. Especially diabetics with active retinal neovascularisation are at high risk of rubeosis iridis after intracapsular cataract extraction. Thirty-five eyes previously treated with panretinal photocoagulation underwent extracapsular cataract extraction with posterior chamber lens implantation. Twenty-eight eyes with retinal neovascularisation required further Argon laser PRP after surgery. Fourteen eyes required YAG-laser capsulotomy. From the group of eyes without YAG-laser capsulotomy none developed neovascular glaucoma. From the YAG laser capsulotomy group six eyes developed rubeosis iridis and neovascular glaucoma. Our results indicate that eyes in which PRP has been performed, have an excellent prognosis after ECCE with posterior chamber lens implantation only if YAG Laser posterior capsulotomy is not performed.     

Early central posterior capsular fibrosis in sulcus-fixated biconvex intraocular lenses

A series of 228 eyes implanted with one-piece all poly(methyl methacrylate) (PMMA) biconvex posterior chamber intraocular lenses was examined for posterior capsule opacification. One hundred forty-one eyes (61.8%) had opacification at an average postoperative period of 19.7 months. Seventy eyes (30.7%) developed an unusual form of early central posterior capsular fibrosis (ECPCF), which was confined to the capsulorhexis opening, sparing the peripheral aspect of the anterior and posterior capsules. Risk factors for developing this form of opacification were close apposition of peripheral anterior and posterior capsules caused by placing a posteriorly vaulted biconvex optic anterior to a capsulorhexis opening smaller than the optic diameter. This opacification occurred most often in cases of haptic fixation in the ciliary sulcus. The cumulative capsulotomy rate in this series was 5.26% at three months, 9.1% at 12 months, and 13.2% at 20 months. Of the ECPCF cases, 34.3% eventually required neodymium: YAG (Nd:YAG) laser capsulotomy; the capsulotomy rate for ECPCF was 4.8 times higher than that for Elschnig pearls. Early onset of ECPCF (average onset = 19.4 weeks) resulted in early Nd:YAG capsulotomy (average = 8.0 months after surgery). One-piece all-PMMA biconvex intraocular lenses may promote early central fibrosis of the posterior capsule if the lens optic is anterior to a capsulorhexis opening smaller than the optic diameter. The early onset of this form of opacification predisposes to earlier Nd:YAG capsulotomy with a higher risk of complications.     

Oropharyngeal candidiasis resistant to fluconazole in patients infected by HIV

Uncomplicated extracapsular cataract extraction (EC) followed by posterior chamber lens implantation (PCL) has been shown to cause long-term lowering of intraocular pressure (IOP) in most patients. Since it has been suggested that Neodymium: YAG (Nd:YAG) laser capsulotomy can provoke persistent glaucoma, we examined the hypothesis that Nd:YAG laser capsulotomy may lead to a permanent elevation of IOP. In a case-control study, we compared two groups of 75 normotensive patients, who were unilaterally pseudophakic after phacoemulsification (PE) + PCL. Patients in group 1 had undergone Nd:YAG capsulotomy at least 2 months prior to this study, while in group 2 the posterior capsule was intact. Both groups were selected at random. Prior to surgery, none of the patients had suffered from glaucoma. Goldmann applanation tonometry was performed in both eyes of each patient and from that the ratio of IOP(pseudophakic)/IOP(phakic) was calculated. The distribution of this ratio for the two groups was compared using the Wilcoxon signed-rank test. There were 52 female and 23 male patients in group 1 versus 56 female and 19 male patients in group 2. Their mean ages were 75 + or -11 (group 1) and 75 + or - 9 years (group 2). The mean interval after PE + PCL was 48 + or - 29 months for patients with Nd:YAG capsulotomy and 16 + or - 17 months for patients with intact posterior capsule. Since the Nd:YAG capsulotomy, 28 + or - 23 months had elapsed on average. The median ratio of IOP (pseudophakic)/IOP(phakic) was higher in the Nd:YAG capsulotomy group than in the group of patients with an intact posterior capsule (1.00 vs. 0.80; p < 0.0001). There was almost no percentile, for which the distribution curve of group 1 intersected the curve of group 2. The median IOP in pseudophakic eyes was 14 mm Hg in group 1 and 12 mm Hg in group 2 (p<0.0001). These results are in accordance with the hypothesis that Nd:YAG capsulotomy will raise IOP permanently in most patients. Therefore Nd:YAG capsulotomy may harbor the risk of glaucomatous optic nerve damage in the long run. Long-term follow-up seems advisable in order to prevent possible glaucoma damage.     

Results of implantation of transsclerally sutured posterior chamber lenses in combination with penetrating keratoplasty

Implantation of transsclerally sutured posterior chamber lenses is one possibility of surgical visual rehabilitation of eyes with pseudophacic or aphacic bullous keratopathy without zonular-capsular support. We analyzed the results and complications of the surgical procedures performed in our institution. PATIENTS AND METHODS: Out of 1567 penetrating keratoplasties and 220 transsclerally sutured posterior chamber lenses that were performed at our institution between 1991 and 1996, patients that underwent penetrating keratoplasty and sutured posterior chamber lens implantation in whom sufficient clinical information was available were selected and analyzed in a retrospective, nonselective study. Surgery was performed by a total of four surgeons and included anterior vitrectomy, inside-out suturing and synechiolysis if necessary. Detailed pre- and intraoperative data, postoperative course and complications were recorded and analyzed. RESULTS: A total of 96 eyes were analyzed (patient age 17-92 years, 49 male, 46 female). Penetrating keratoplasty was performed for pseudophacic (63) oder aphacic (15) bullous keratopathy or for corneal scars following penetrating injury (18). Mean follow-up was 22 months. In 82 of 96 eyes, visual acuity improved following surgery. Complications included rhegmatogenous retinal detachment in 4 eyes, graft rejection in 5 eyes, secondary angle-closure glaucoma caused by preexisting anterior synechiae in 7 eyes, and persisting cystoid macular edema in 19 eyes. Luxation or subluxation of the IOL and endophthalmitis were not observed in any of the patients. CONCLUSION: Implantation of transsclerally sutured posterior chamber lenses appears to be a safe procedure and is considered by us to be the procedure of choice to correct aphacia during penetrating keratoplasty in eyes with absent zonular-capsular support. The majority of postoperative complications is apparently caused by preexisting problems related to previous surgery and/or trauma, such as peripheral anterior synechiae, vitreous incarceration or cystoid macular edema.     

Long-term results after drainage of premacular subhyaloid hemorrhage into the vitreous with a pulsed Nd:YAG laser

OBJECTIVE: To investigate the effects of drainage of premacular subhyaloid hemorrhage into the vitreous with an Nd:YAG laser in a large series of patients with long-term follow-up. METHODS: A retrospective review was conducted on 21 eyes with a circumscribed premacular subhyaloid hemorrhage of various causes. These eyes were treated with a pulsed Nd:YAG laser to drain the entrapped blood into the vitreous. The period of review ranged from 12 to 32 months (mean, 22 months). RESULTS: In 16 eyes, visual acuity improved within 1 month. Four eyes had persistent, dense, nonclearing vitreous opacity for at least 3 months and finally required vitrectomy. One clotted hemorrhage did not drain into the vitreous. Final visual outcome was determined by the underlying diagnosis, such as Valsalva retinopathy (7 eyes), diabetic retinopathy (7 eyes), branch retinal vein occlusion (4 eyes), and retinal macroaneurysm, Terson syndrome, or blood dyscrasia (1 eye each). Eyes with Valsalva retinopathy fared the best. Complications included a macular hole in 1 eye and a retinal detachment from a retinal break in a myopic patient. CONCLUSIONS: Drainage of premacular subhyaloid hemorrhage into the vitreous with an Nd:YAG laser is a viable treatment alternative for eyes with recent bleeding. However, a macular hole and a retinal detachment were observed as complications. Thus, to establish Nd:YAG laser treatment as a routine procedure, the risks and benefits have to be weighed in a randomized trial and compared with those of deferral of treatment or primary vitrectomy.     

Incidence, causes, and neodymium:YAG laser treatment of pupillary capture

OBJECTIVE: To report the incidence of and factors associated with pupillary capture after cataract surgery and evaluate the outcomes of treatment with the neodymium:YAG (Nd:YAG) laser. SETTING: Unit of Ophthalmology, University of Edinburgh, and Royal Infirmary of Edinburgh Trust Hospital, Edinburgh, United Kingdom. METHODS: This prospective study comprised 792 consecutive patients having cataract extraction by one surgeon from 1989 to 1993. Outcome measures were incidence of pupillary capture associated with eye disease and treatment, surgical technique, and intraocular lens (IOL) placement and style; postoperative progress; and results of Nd:YAG treatment. RESULTS: Pupillary capture developed in 30 of the 764 patients (3.9%) having implantation of a posterior chamber IOL a mean of 14 weeks postoperatively (range 2 to 44 weeks). The incidence was significantly higher in eyes with angle-closure glaucoma, combined glaucoma and cataract surgery, can-opener capsulotomy, manual extraction, sulcus IOL implantation, large-optic IOLs, and one-piece IOLs. Neodymium:YAG laser treatment was successful in 8 of 12 eyes. CONCLUSION: Pupiliary capture may be anticipated and when recognized at an early stage, treated successfully with an Nd:YAG laser in most cases.     

A randomised prospective comparison of operative peripheral iridectomy and Nd:YAG laser iridotomy treatment of acute angle closure glaucoma: 3 year visual acuity and intraocular pressure control outcome

AIM: To compare visual acuity and intraocular pressure outcomes 3 years after treatment of acute angle closure glaucoma (AACG) by operative peripheral iridectomy (PI) or Nd:YAG laser iridotomy (YAG PI). METHODS: A prospective study of consecutive patients presenting to one ophthalmology department with uniocular AACG during a 2 year period. Following informed consent patients were randomised to bilateral PI or bilateral YAG PI. Three years after treatment the mean Snellen visual acuity converted to logMAR scores of the two groups was compared using the unpaired Student's t test. The number of patients with normal intraocular pressure with no further treatment in each group was compared using the chi 2 test with Yates's correction. RESULTS: 21 patients underwent bilateral PI and 27 bilateral YAG PI. Three years after treatment visual acuity was 0.30 (SD 0.28) log MAR units for PI eyes and 0.57 (0.67) logMAR units for YAG PI eyes (p = 0.08, NS). 15 (70.4%) PI eyes and 19 (71.8%) YAG PI eyes had an intraocular pressure less than 21 mm Hg with no further treatment (NS). CONCLUSIONS: There was no significant difference in visual acuity or intraocular pressure control 3 years after treatment of AACG with PI or YAG PI.     

Experimental ocular surgery with a high-repetition-rate erbium:YAG laser

PURPOSE: To evaluate the performance in ocular surgery and the ocular tissue interactions resulting from increasing the maximum repetition rate of a pulsed-mode erbium:YAG laser system from 30 to 200 pulses per second. METHODS: An erbium:YAG laser was used that emitted at 2.94 microm with an output graduated from 0.2 mJ to 25 mJ and a repetition rate from 2 Hz to 200 Hz and that was equipped with a flexible optical fiber attached to various interchangeable 20-gauge endoprobes to perform ocular surgery in enucleated pig eyes. The specific maneuvers were performed in close contact in nontransmitting aqueous media and included inner retinal ablation, retinotomy, lens capsulotomy, lens ablation, iridotomy, and iridectomy. Selected tissue specimens were examined by light microscopy. RESULTS: Increasing the repetition rate to the 200-Hz range significantly improved the smoothness, continuity, and speed of all surgical maneuvers. Compared with the 30-Hz rate, substantially lower energies per pulse were efficient with the 200-Hz rate. The "sticking effect" between the tip of the probe and the target tissue at low-repetition rates, which resulted in discontinuation of the surgical maneuver, particularly during lens surgery, was eliminated with the use of high-repetition rates. Use of high-repetition rates produced a zone of residual thermal damage less than 30 microm in all ocular tissues. The histologic findings of tissue interactions were comparable to those obtained in published studies in which the same wavelength and low hertz rates were used. CONCLUSIONS: The high-repetition-rate erbium:YAG laser technology described is advantageous, compared with low-repetition-rate erbium:YAG lasers, and is applicable in a variety of ocular surgical procedures. Innovations in endoprobe design and further study will determine its role in contemporary ocular surgery.     

Pseudophakic retinal detachment in high axial myopia

PURPOSE: To investigate the effect of extracapsular cataract surgery with intraocular lens (IOL) implantation and neodymium:YAG (Nd:YAG) laser posterior capsulotomy on the rate of retinal detachment (RD) in myopic eyes with an axial length of 27 mm or more. SETTING: Department of Ophthalmology, University of Giessen, Germany. METHODS: This retrospective, nonrandomized study comprised the records of 386 consecutive surgical procedures in 275 patients performed between December 1985 and December 1993. In May 1994, all patients were asked by a mailed questionnaire whether they had had an RD in either eye or laser treatment for posterior capsule opacification. Responses from 190 patients concerning 253 surgical procedures were evaluated. RESULTS: The pseudophakic RD rate was 0.8% (two cases). One patient developed aphakic RD after IOL explanation. One expulsive choroidal hemorrhage occurred during secondary IOL implantation. Four eyes (1.6%) had vitreous loss, and 74 eyes (29.2%) had an Nd:YAG capsulotomy. Mean axial length was 29.2 mm +/- 1.71 (SD), mean follow-up was 3.8 +/- 2 years, and mean age at surgery was 69.8 +/- 12 years. CONCLUSION: Pseudophakia with no other risk factor posed little additional risk for RD in eyes with high axial myopia; however, Nd:YAG laser posterior capsulotomy was a risk factor for pseudophakic RD. Complicated surgery, such as a secondary procedure or vitreous loss, and young age were major causative factors.     

Comparative results of combined procedures for glaucoma and cataract: II. Limbus-based versus fornix-based conjunctival flaps

BACKGROUND AND OBJECTIVE: One of the variables to be considered in a combined procedure for glaucoma and cataract is the type of conjunctival flap to be used. The objective of this study was to compare the effects of limbus-based and fornix-based conjunctival flaps on postoperative long-term intraocular pressure (IOP) control and visual acuity after combined trabeculectomy with phacoemulsification. PATIENTS AND METHODS: The authors retrospectively reviewed the charts of 189 patients (215 eyes) who underwent combined trabeculectomy with phacoemulsification, posterior chamber intraocular lens (IOL) implantation, and intraoperative mitomycin-C administration and who had a minimum follow-up of 12 months. The results of the limbus-based (151 eyes) versus fornix-based (64 eyes) conjunctival incisions used in these combined procedures were compared. RESULTS: In the limbus-based conjunctival flap group, 146 eyes (97%) achieved an IOP of less than 20 mm Hg, with or without medication; 62 eyes (97%) of the fornix-based conjunctival flap group (P > .05) achieved this result. A visual acuity of 20/40 or better was noted in 106 eyes (70%) in the limbus-based conjunctival flap group and in 45 eyes (70%) in the fornix-based conjunctival flap group (P > .05) at the last examination. Early wound leakage was observed more frequently in the fornix-based conjunctival flap group (8% vs 1%) (P = .014); however, it was not a serious clinical problem, as only 1 eye required surgical repair. Posterior capsular opacification was found more often in the limbus-based conjunctival flap group (25% vs 14%) (P = .072) and required more frequent laser capsulotomy (22% vs 9%) (P = 0.03). CONCLUSION: Limbus-based and fornix-based conjunctival flaps appear to be comparable with respect to postoperative IOP control and visual acuity after a combined trabeculectomy with phacoemulsification and posterior chamber IOL implantation in cases supplemented by intraoperative mitomycin-C.     

Experimental erbium: YAG laser photoablation of trabecular meshwork in rabbits: an in-vivo study

Photoablative laser trabecular surgery has been proposed as an outflow-enhancing treatment for open-angle glaucoma. The aim of the study was to investigate the time course of repair response following low-thermal Erbium: YAG laser trabecular ablation. In 20 anaesthetized rabbits gonioscopically controlled ab-interno photoablation of the ligamenta pectinata and underlying trabecular meshwork (TM) was performed with a single-pulsed (200 microseconds) Erbium: YAG (2.94 microns) laser. The right eye received 12-15 single laser pulses (2 mJ) delivered through an articulated zirconium fluoride fiberoptic and a 200 microns (core diameter) quartz fiber tip, the left unoperated eye served as control. At time intervals of 30 minutes, 2, 10, 30, and 60 days after laser treatment, eyes were processed for light- and scanning electron microscopy. The applied energy density of 6-4 J cm-2 resulted in visible dissection of the ligamenta pectinata and reproducible microperforations of the TM exposing scleral tissue accompanied by blood reflux from the aqueous plexus. The initial ablation zones measured 154 +/- 36 microns in depth and 45 +/- 6 microns in width. Collateral thermal damage zones were 22 +/- 8 microns. At two days post-operative, ablation craters were still blood- and fibrin-filled. The inner surface of the craters were covered with granulocytes. No cellular infiltration of the collateral thermal damage zone was observed. At 10 days post-operative, progressive fibroblastic proliferation was observed, resulting in dense scar tissue formation with anterior synechiae, proliferating capillaries and loss of intertrabecular spaces inside the range of former laser treatment at 60 days post-operative. Trabecular microperforations were closed 60 days after laser treatment in all rabbits. IOP in treated and contralateral eyes did not significantly change its level during whole period of observation. Low-thermal infrared laser energy with minimal thermal damage to collateral structures could not effectively prevent early scarring of trabecular surgery in rabbits.     

Nd:YAG laser therapy of recurrent epistaxis in hereditary hemorrhagic telangiectasia

BACKGROUND: Epistaxis is the leading symptom of hereditary hemorrhagic teleangiectasia (HHT). Over the last years several laser systems have been used for therapy. Only a few studies have published results of Nd:YAG laser therapy evaluating a larger number of patients. PATIENTS AND METHODS: From 1987 through 1996, forty-one patients with HHT were treated with a Nd:YAG laser due to recurrent epistaxis at the Department of Otorhinolaryngology of Kiel University. Thirty-two patients were followed-up over a period of at least 24 months. A centripetal technique was used for endonasal laser light application (15-25 Watts; 0.1-0.5 s), i.e., the laser light was applied from the periphery towards the center of the angiodysplasia. Intensive preoperative and postoperative nasal care with ointments was performed. RESULTS: Bleeding frequency and intensity decreased in 30 (94%) patients. Duration of the therapeutical success differed individually and varied from seven weeks to 14 months. Repeated laser therapy was necessary in 27 of 32 patients. CONCLUSION: The Nd:YAG laser is a suitable tool in the treatment of epistaxis in HHT. This procedure is less traumatic, less painful, and can be repeated multiple times. Nd:YAG laser therapy and other therapeutic options cannot obtain a lasting cure of Rendu-Osler-Weber syndrome. However, in the vast majority of cases recurrent nasal bleeding as the dominant symptom can be reduced in frequency as well as in intensity.     

Spontaneous disappearance of Elschnig pearls after neodymium:YAG laser posterior capsulotomy

Posterior capsule opacification (PCO) from Elschnig pearl formation is a common complication of extracapsular cataract extraction. After PCO treatment by neodymium:YAG (Nd:YAG) laser posterior capsulotomy, Elschnig pearls may undergo hyperproliferation at the edge of the capsulotomy, which may close it. We have seen six eyes in five patients who presented with spontaneous disappearance of Elschnig pearls, resulting in a perfectly clear posterior capsule several years after an Nd:YAG posterior capsulotomy. Possible causes include (1) falling of pearls into the vitreous through the capsulotomy; (2) phagocytosis of pearls by macrophages; (3) cell death by apoptosis.     

The effect of radiation therapy on the kinetics of in vitro lymphocyte response to mitogens

Iridotomies were made in rabbit and human eyes using a continuous wave argon laser. Several of these have been studied histologically to determine the short- and long-term effects on the iris, cornea, lens and retina. Thirty-three eyes of patients with angle-closure glaucoma were treated by argon laser iridotomy and followed for periods of up to twelve months. In two eyes, planned cataract surgery was performed shortly after the laser iridotomy and histologic specimens of the iris were examined. From the experimental and clinical studies, an evaluation was made of the complications and clinical usefulness of the continuous wave argon laser as a means to produce iridotomies for the treatment of angle-closure glaucoma. Further long-term controlled studies are recommended to document the role of laser iridotomy.