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|Vitrectomy is an effective treatment for visually disabling vitreous opacities (floaters) but carries significant surgical risk. Nd:YAG laser vitreolysis using newer technology has been shown safe and effective in treating symptomatic Weiss ring vitreous floaters. These Weiss rings, as well as amorphous opacities in the mid- to posterior vitreous, can be impossible to visualize or treat using conventional YAG lasers. In the cases presented here, undetected symptomatic amorphous type posterior vitreous floaters were confirmed with assistance of a novel optical coherence tomography application and successfully treated using a YAG laser optimized for vitreolysis. These cases suggest that with proper technology and technique, laser vitreolysis may be safer and more effective than previously recognized.|
IMPORTANCE: Vitreous floaters are common and can worsen visual quality. YAG vitreolysis is an untested treatment for floaters.
OBJECTIVE: To evaluate YAG laser vitreolysisvsshamvitreolysisforsymptomaticWeissring floaters from posterior vitreous detachment.
DESIGN, SETTING, AND PARTICIPANTS: This single-center,masked,sham-controlled randomized clinical trial was performed from March 25, 2015, to August 3, 2016, in 52 eyes of 52 patients (36 cases and 16 controls) treated at a private ophthalmology practice.
INTERVENTIONS: PatientswererandomlyassignedtoYAGlaservitreolysisorshamYAG (control).
MAIN OUTCOMES AND MEASURES: Primary6-monthoutcomesweresubjectivechange measured from 0% to 100% using a 10-point visual disturbance score, a 5-level qualitative scale, and National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25). Secondary outcomes included objective change assessed by masked grading of color fundus photography and Early Treatment Diabetic Retinopathy Study best-corrected visual acuity.
RESULTS: Fifty-twopatients(52eyes;17menand35women;51whiteand1Asian)with symptomatic Weiss rings were enrolled in the study (mean [SD] age, 61.4 [8.0] years for the YAG laser group and 61.1 [6.6] years for the sham group). The YAG laser group reported greater symptomatic improvement (54%) than controls (9%) (difference, 45%; 95% CI, 25%-64%; P < .001). In the YAG laser group, the 10-point visual disturbance score improved by 3.2 vs 0.1 in the sham group (difference, −3.0; 95% CI, −4.3 to −1.7; P < .001). A total of 19 patients (53%) in the YAG laser group reported significantly or completely improved symptoms vs 0 individuals in the sham group (difference, 53%; 95% CI, 36%-69%, P < .001). Compared with sham, NEI VFQ-25 revealed improved general vision (difference, 16.3; 95% CI, 0.9-31.7; P = .04), peripheral vision (difference, 11.6; 95% CI, 0.8-22.4; P = .04), role difficulties (difference, 17.3; 95% CI, 8.0-26.6; P < .001), and dependency (difference, 5.6; 95% CI, 0.5-10.8; P = .03) among the YAG laser group. Best-corrected visual acuity changed by −0.2 letters in the YAG laser group and by −0.6 letters in sham group (difference, 0.4; 95% CI, −6.5 to 5.3; P = .94). No differences in adverse events between groups were identified.
CONCLUSIONS AND RELEVANCE: YAGlaservitreolysissubjectivelyimprovedWeissring–related symptoms and objectively improved Weiss ring appearance. Greater confidence in these outcomes may result from larger confirmatory studies of longer duration.
IMPORTANCE: Use of laser vitreolysis for symptomatic floaters has increased in recent years, but prospective studies are not available and the complication profile is poorly understood.
OBJECTIVE: To analyze cases of complications following laser vitreolysis as voluntarily reported to the American Society of Retina Specialists Research and Safety in Therapeutics (ASRS ReST) Committee, an independent task force formed to monitor device-related and drug-related safety events.
DESIGN, SETTING, AND PARTICIPANTS: A retrospective assessmentwas performed of all cases of complications following laser vitreolysis that were voluntarily reported by practitioners throughout the United States to the ASRS ReST Committee from the first report on September 19, 2016, through March 16, 2017, the date of data analysis and manuscript writing.
MAIN OUTCOMES AND MEASURES: Complications reported to the ASRS ReST Committee following laser vitreolysis were analyzed by type to gain an understanding of the spectrum of potential complications. RESULTS A total of 16 complications following laser vitreolysis were reported in 15 patients by 7 US vitreoretinal specialists during the study period. Complications included elevated intraocular pressure leading to glaucoma; cataracts, including posterior capsule defects requiring cataract surgery; retinal tear; retinal detachment; retinal hemorrhages; scotomas; and an increased number of floaters.
CONCLUSIONS AND RELEVANCE: This report presents a spectrum of complications reported to the ASRS ReST Committee across 6 months. The rate of complications cannot be determined because the denominator of total cases is unknown. Also, these findings cannot determine whether there is a causal association between these complications and laser vitreolysis. Prospective studies are warranted to better understand the efficacy of this procedure and the frequency of attendant complications. Until then, practitioners should be aware of the profile of potential complications to properly inform patients during the consent process. The ASRS ReST Committee will continue to monitor device-related and drug-related adverse events and encourages active surveillance and reporting by all physicians.
Background: Neodymium–yttrium-aluminium-garnet Nd:YAG) laser vitreolysis has been proposed as a treatment modality for symptomatic vitreous floaters. The purpose of this paper is to report two cases of cataracts associated with posterior capsular compromise, induced by Nd:YAG laser vitreolysis for symptomatic vitreous floaters.
Method: Case series.
Results: Two patients who underwent ND:YAG laser vitreolysis for symptomatic floaters, presented with decline in visual acuity in the treated eye after the laser procedure. At the slit-lamp biomicroscope, each patient was found to have a posterior subcapsular cataract in the treated eye, with obvious loss of integrity of the posterior capsule. These two patients underwent cataract extraction by the same surgeon via phacoemulsification. Both eyes were found to have a defect in the posterior capsule intraoperatively. In both cases, a three-piece acrylic intraocular lens implant was placed in the sulcus, achieving optic capture. The best-corrected visual acuity (BCVA) was 20/20 in both patients, at 1 month following the surgery. At 2 months, one patient had a BCVA of 20/15. The second patient maintained a BCVA of 20/20 at 3 months.
Conclusions: Secondary cataract formation accompanied by loss of integrity of the posterior capsule is a potential complication of Nd:YAG laser vitreolysis for symptomatic floaters.
Background and Objective: To assess the current attitudes, beliefs, and practice patterns among vitreoretinal surgeons when dealing with symptomatic floaters in patients with otherwise healthy eyes.
Purpose: To evaluate the short-term clinical results and safety of Ultra Q neodymium-doped yttrium aluminium garnet (Nd:YAG) laser treatment for vitreous floaters.
Purpose of review: To review the pros and cons of small-gauge vitrectomy for symptomatic floaters.
Recent Findings: Current treatment options for floaters include Nd:YAG vitreolysis and pars plana vitrectomy. There are risks and benefits associated with vitrectomy for floaters. However, small-gauge vitrectomy is a minimally invasive way of removing the floaters. The current literature demonstrates vitrectomy has some risk, but is highly effective at improving vision, symptoms, contrast sensitivity, and quality of life.
Summary: Small-gauge vitrectomy for floaters is a well tolerated and effective procedure to remove the symptomatic floaters. Symptomatic patients are willing to take some risk to have their troublesome vitreous floaters removed, often resulting in an improvement in their vision and quality of life.
Abstract: Floaters most commonly occur in the middle age due to age-related changes in vitreous structure and light scattering by the posterior vitreous cortex after collapse of the vitreous body during posterior vitreous detachment (PVD). In youth, floaters are most often due to myopic vitreopathy. Vitreous floaters can have a negative impact on visual function and in turn the quality of life. Techniques to characterize floaters clinically include ultrasound imaging, optical coherence tomography, and dynamic light scattering for structural characterization. Functional impact can be assessed by straylight measurements, as well as contrast sensitivity testing. When the severity of floater symptomatology is significant, commonly used therapies include neodymium:yttrium-aluminum-garnet (YAG) laser and limited 25-gauge vitrectomy. While the former is of unproven efficacy, the latter has been shown to be a safe, effective, and definitive cure that improves patients’ quality of life and eradicates symptomatology produced by light scattering and diffraction. It is thus reasonable to offer limited vitrectomy to individuals who have attempted to cope unsuccessfully and in whom functional deficit can be objectively demonstrated by testing contrast sensitivity, an important aspect of vision.
We all recognize that we cannot dismiss a patient who presents to us with symptomatic vitreous opacities: however, patient education regarding observation versus surgical intervention is of paramount importance when managing this condition. Undoubtedly, the use of PPV to manage floaters remains a controversial subject and the community needs to reach a consensus regarding standard of care for this condition.
Purpose: To illustrate three cases of chronic open angle glaucoma secondary to the Nd:YAG laser vitreolysis procedure for symptomatic vitreous floaters.
Design: Observational case series.
Methods: Location of the study was the Doheny Eye Institute. Three eyes of two patients who developed chronic open angle glaucoma after Nd:YAG vitreolysis for symptomatic floaters presented with very high intraocular pressure (IOP>40 mmHg) were selected. The time from the laser treatment to the onset of elevated pressure ranges from 1 week to 8 months. There was no associated inflammation, steroid use, or other identifiable cause of chronic IOP elevation.
Results: All eyes were treated initially with glaucoma medication, followed by selective laser trabeculoplasty (SLT) and eventually glaucoma surgery (Trabectome) in two eyes for disease management. In all eyes, intraocular pressures were eventually stabilized within a normal pressure range from 18 to 38 months following Nd:YAG vitreolysis. At the latest follow-up post-surgery, all eyes had intraocular pressures of 22 mmHg or less with or without medications.
Conclusions: Secondary open angle glaucoma is a complication of Nd:YAG vitreolysis for symptomatic floaters that may present with an increase in intraocular pressure immediately, or many months after the surgery. Furthermore this complication may be permanent and require chronic medical therapy or glaucoma surgery.
Inder Paul Singh, MD, shares his surgical pearls for how advances in YAG laser vitreolysis can make the procedure a safe, effective option for the treatment of floaters.
Importance: Prospective long-term analyses of the role of drug-inducedmydriasis and laser peripheral iridotomy (LPI) are needed to identify and manage the eyes of patients with pigment dispersion syndrome (PDS) at risk for progressing to ocular hypertension.
Conclusions and Relevance: At the end of the 10-year follow-up, (1) approximately one-third of the whole PDS patient population showed an IOP increase of 5mmHg or higher in at least 1 eye; (2) phenylephrine testing identified eyes at high risk for developing IOP elevation; and (3) LPI, when performed on high-risk eyes, reduced the rate of IOP elevation to the same level as the low-risk eyes.
Surgeon’s clinical experience shows therapy yields robust safety profile, quality-of-life benefits
Abstract: A case of Staphylococcus caprae endophthalmitis in a young patient following pars plana vitrectomy for symptomatic vitreous floaters is reported here. Recent literature suggests that there is an increasing trend of performing pars plana vitrectomy for symptomatic floaters. Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters.
Purpose: Floaters impact vision but the mechanism is unknown. We hypothesize that floaters reduce contrast sensitivity function, which can be normalized by vitrectomy, and that minimally invasive vitrectomy will have lower incidences of retinal tears (reported at 30%) and cataracts (50–76%).
Methods: Seventy-six eyes (34 phakic) with floaters were evaluated in 2 separate studies. Floater etiologies were primarily posterior vitreous detachment in 61 of 76 eyes (80%) and myopic vitreopathy in 24 of 76 eyes (32%). Minimally invasive 25G vitrectomy was performed without posterior vitreous detachment induction, leaving anterior vitreous, and using nonhollow probes for cannula extraction. Efficacy was studied prospectively (up to 9 months) in 16 floater cases with Freiburg Acuity Contrast Testing (Weber index [%W] reproducibility = 92.1%) and the National Eye Institute Visual Function Questionnaire. Safety was separately evaluated in 60 other cases followed up on an average of 17.5 months (range, 3–51 months).
Results: Floater eyes had 67% contrast sensitivity function attenuation (4.0 ± 2.3 %W; control subjects = 2.4 ± 0.9 %W, P , 0.013). After vitrectomy, contrast sensitivity function normalized in each case at 1 week (2.0 ± 1.4 %W, P , 0.01) and remained normal at 1 month (2.0 ± 1.0 %W, P , 0.003) and 3 months to 9 months (2.2 ± 1.5 %W, P, 0.018). Visual Function Questionnaire was 28.3% lower in floater patients (73.2 ± 15.6, N = 16) than in age-matched control subjects (93.9 ± 8.0, N = 12, P , 0.001), and postoperatively improved by 29.2% (P , 0.001). In the safety study of 60 floater cases treated with vitrectomy, none developed retinal breaks, infection, or glaucoma after a mean follow up of 17.5 months. Only 8 of 34 cases (23.5%) required cataract surgery (none younger than 53 years) at an average of 15 months postvitrectomy.
Conclusion: Floaters lower contrast sensitivity function, which normalizes after vitrectomy. Visual Function Questionnaire quantified improvement in satisfaction. Not inducing posterior vitreous detachment reduced retinal tear incidence from 30% to 0% (P , 0.007). Postvitrectomy cataract incidence was reduced from 50% to 23.5% (P , 0.02). This approach thus seems effective and safe in alleviating the visual dysfunction induced by floaters.
A 65-year-old male underwent intravitreal triamcinolone acetonide (IVTA) injection for treating a clinically significant macular edema (CSME) due to background diabetic retinopathy in his left eye. On the first postoperative day, visual acuity dropped from 20/80 to hand movements. Slit-lamp examination showed the drug between the posterior capsule of the lens and the anterior hyaloid face. Two weeks later, visual acuity and the milky fluid seemed unchanged. Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser anterior hyaloidotomy was performed. One week later, slit-lamp examination of the retrolental space revealed the complete disappearance of triamcinolone and intraocular pressure remained stable. After a follow-up period of 2 months, visual acuity increased to 20/50 with the lens remaining clear. Nd:YAG laser anterior hyaloidotomy is an effective, simple, useful and minimally invasive outpatient procedure in patients with persistent entrapment of triamcinolone behind the crystalline lens, allowing the drug to clear without trauma to the lens.
In this issue of the Journal, Wagle and associates present fascinating new information concerning the utility value of floaters, as expressed by patients. Utility values allow an objective quantification of the functional quality of life associated with a specific “disease” state. A utility value of 1.0 implies a perfect “health” state, while death has a utility value of 0.0. The findings of this study indicate that the utility values of floaters are equal to AMD and lower than diabetic retinopathy and glaucoma. According to this study, floaters have lower utility values than mild angina, mild stroke, colon cancer, and asymptomatic HIV infection. This indicates that floaters have a significant negative impact on the quality of life as compared to ocular as well as systemic diseases.
Purpose: To ascertain the health-related quality of life associated with symptomatic degenerative vitreous floaters.
Design: Cross-sectional questionnaire survey.
Methods: In this institution-based study, 311 outpatients aged 21 years and older who presented with symptoms of floaters were enrolled. Data from 266 patients (85.5%) who completed the questionnaire were analyzed. Utility values were assessed using a standardized utility value questionnaire. The time trade-off (TTO) and standard gamble (SG) for death and blindness techniques were used to calculate the utility values. Descriptive, univariate, and multivariate analyses were performed using Stata Release 6.0.
Results: The mean age of the study population was 52.9 ± 12.02 years (range, 21-97). The mean utility values were 0.89, 0.89, and 0.93 for TTO, SG (death), and SG (blindness), respectively. Patients aged ≤55 years reported significantly lower SG (blindness) utility values when compared with patients above 55 years of age (age ≤55 = 0.92, age >55 = 0.94, P = .007). Utility measurements did not demonstrate significant relationship with any of the other socio-demographic variables examined in this study. The utility values did not demonstrate any significant relationship with other ocular characteristics such as duration of symptoms, presence of a posterior vitreous detachment, and presence or severity of myopia.
Conclusions: Symptomatic degenerative vitreous floaters have a negative impact on health-related quality of life. Younger symptomatic patients are more likely to take a risk of blindness to get rid of the floaters than older patients.
The vitreoretinal interface is involved in a wide range of vitreoretinal disorders and separation of the posterior vitreous face from the retinal surface is an essential part of vitrectomy surgeries. A diverse range of enzymatic and non-enzymatic agents are being studied as an adjunct before or during vitrectomy to facilitate the induction of posterior vitreous detachment. There is a significant body of knowledge in the literature about different vitreolytic agents under investigation for a variety of pathologies involving the vitreoretinal interface which will be summarized in this review.
Purpose of Study: To determine the efficacy of Nd:YAG vitreolysis and pars plana vitrectomy in the treatment of vitreous floaters.
Methods: This is a single centre retrospective study of 31 patients (42 eyes) who underwent 54 procedures, Nd:YAG vitreolysis or pars plana vitrectomy, for the treatment of vitreous floaters between January 1992 and December 2000. Main outcome measures were percentage symptomatic improvement following treatment and incidence of post-operative complications. Statistical analysis was performed using the Fisher exact test.
Results: Posterior vitreous detachment was the primary cause of floaters in all 42 eyes with co-existing vitreous veils in three eyes and asteroid hyalosis in two eyes. Thirty-nine of 42 eyes received Nd:YAG vitreolysis. Thirty-eight percent found Nd:YAG vitreolysis moderately improved their symptoms while 61.5% found no improvement. After an average of 14.7 months follow-up no post-operative complications were recorded. Fifteen eyes underwent a pars plana vitrectomy, one with combined phacoemulsification and posterior chamber implantation and 11 following unsuccessful laser vitreolysis. Pars plana vitrectomy resulted in full resolution of symptoms in 93.3% of eyes. One patient developed a post-operative retinal detachment which was successfully treated leaving the patient with 6/5 VA.
Conclusions: Patients' symptoms from vitreous floaters are often underestimated resulting in no intervention. This paper shows Nd:YAG vitreolysis to be a safe but only moderately effective primary treatment conferring clinical benefit in one third of patients. Pars plana vitrectomy, while offering superior results, should be reserved for patients who remain markedly symptomatic following vitreolysis, until future studies further clarify its role in the treatment of patients with floaters and posterior vitreous detachment.
Ten eyes of nine patients were treated for very disturbing vitreous floaters with the technique of Nd-YAG laser vitreolysis. The Scanning Laser Ophthalmoscope (SLO) was used to objectivate the position, the size and the motility of the vitreous floaters with respect to the patient's visual axis, which can be precisely located with the SLO. With this technique it was possible to define more precisely some eligibility criteria for Nd-YAG laser treatment of vitreous floaters and to classify the vitreous floaters in ill-suspended and well-suspended floaters in the vitreous body, the well-suspended floaters responding better to treatment compared to the ill-suspended vitreous floaters. The treatment was performed using the Q-Switched Nd-YAG Laser type Nanolas 15S of Alcon.
An 18-YEAR-OLD woman who was 36 weeks' pregnant had a 1-week history of a large red scotoma in the superior half of her vision in the left eye. She denied trauma or pain. Her ophthalmic and medical histories were negative for diabetes mellitus and systemic hypertension. Visual acuity was 20/20 OD and counting fingers OS. There was no afferent pupillary defect. Intraocular pressure was normal in both eyes. Extraocular motility was normal and visual fields were full to confrontation in both eyes. Anterior segment examination results were normal. Results of a dilated fundus examination were normal in the right eye; the left eye showed a large area of preretinal hemorrhage over the macula.
Aim: The aim of the paper is to present results obtained after photodisruption of non-resorptive vitreous floaters by means of the Nd:YAG laser.
Material and Methods: 10 patients were observed. The energy of a single exposition ranged from 3mJ to 7mJ, and the total energy needed to break the floaters from 56mJ to 216mJ. In all the patients the floaters got disrupted and were moving towards the periphery of the vitreous humour.
Results: Only 2 patients reported persistence of tiny clouds in the visual field. No complications were observed. It seems that the use of Nd:YAG laser can, in selected cases, be an effective method of treating floaters of the vitreous humour.
A 63-year old man, with a large central vitreous floater, underwent a Nd:YAG laser posterior hyaloidotomy. Although the vitreous floater disappeared from the central optical axis, visual acuity did not improve. Microperimetry performed with the SLO revealed an absolute scotoma, which corresponded well in shape and dimension with the original vitreous floater. This finding suggests that a fragment of the neurosensory retina became detached together with the internal limiting membrane in the process of the vitreous collapse.
Purpose To determine the applicability of laser segmentation for severing fibrovascular tissue and hyaloid interfaces in the treatment of tractional complications of proliferative diabetic retinopathy.
Methods: A prototype neodymium:yttrium-lithium-fluoride (Nd:YLF) picosecond pulse photodisruptive laser was used in eight eyes (seven patients) with proliferative diabetic retinopathy as part of a Food and Drug Administration-approved phase 1 protocol. There were three indications for treatment: type I: distortion and shallow elevation of the macular caused by taut, adherent, posterior hyaloid interface (two eyes); type II: traction retinal detachment involving the fovea (two eyes); and type III: fovea-threatened, traction retinal detachment (four eyes). Traction release was accomplished by laser segmentation of the detached hyaloid interfaces and fibrotic, contracted proliferative tissue. The Nd:YLF uses low pulse energy (0.10 mJ, 1,000 pulses per second for 10 consecutive seconds) that allows tissue cutting near the retinal surface.
Results: Both type I eyes had relief of traction forces; visual acuity improved from 20/400 to 20/50 in one eye; the other remained stable. Of the two type II eyes, one had anatomic reattachment of the fovea with improvement in visual acuity (hand movements to 20/50); the second required vitrectomy. Of the four type III eyes, all had anatomic improvement; three maintained pretreatment acuity; the fourth eye developed vitreous haemorrhage at 6 months and underwent vitrectomy. Three treatments (two eyes) caused vitreous haemorrhage that resulted in a transient drop in acuity (1 to 2 lines). No patient developed a retinal break or choroidal haemorrhage.
Conclusions: In a small pilot study, the Nd:YLF laser segmented proliferative tissue near the retinal surface and elevated hyaloid interfaces. In selected cases, this may enable flattening of traction retinal detachment or release of retinal distortion.
We examined biomicroscopically the vitreous and retinal conditions of 902 consecutive symptomatic eyes (785 patients) to ascertain the relationship between floaters, light flashes, or both, and complications of posterior vitreous detachment. Of 785 patients, 785 symptomatic eyes were divided as follows: group 1, 342 eyes with floaters alone; group 2, 240 eyes with floaters and light flashes; and group 3, 203 eyes with light flashes alone. We also studied 636 asymptomatic fellow eyes. The prevalence of posterior vitreous detachment was significantly higher in groups 1 (138 of 342, 40%), 2 (214 of 240, 89%), and 3 (137 of 203, 67%) than in the asymptomatic eyes (127 of 636, 20%), in group 2 than in groups 1 and 3, and in group 3 than in group 1 (P = .01). The prevalence of retinal breaks in eyes with posterior vitreous detachment was 5% (seven of 138), 13% (27 of 214), 12% (16 of 137), and 4% (five of 127) in groups 1, 2, 3, and the asymptomatic eyes, respectively; the prevalence was significantly higher in groups 2 and 3 than in asymptomatic eyes (P = .02 and P = .04) and group 1 (P = .04 and P = .05). The prevalence of vitreous hemorrhage in eyes with retinal breaks was 71% (five of seven), 70% (19 of 27), and 6% (one of 16) in groups 1, 2, and 3, respectively. Of 117 patients with bilateral symptoms, 105 (90%) had the same symptoms and 104 (89%) had the same vitreoretinal relationship bilaterally.
Fifteen cases of vitreous floaters with serious psychological reactions have been collected. By using a direct ophthalmoscope, causal vitreous opacities were detected. The opacities were photodisrupted with neodymium YAG laser, using energy levels of 5 to 7.1 mJ and total energy 71 to 742.0 mJ. Symptoms completely disappeared immediately after treatment in all 15 cases. There were no intraoperative or postoperative complications noted during a follow up period of at least 1 year. To our knowledge, the use of neodymium YAG laser to treat vitreous floaters has not been previously described. Our initial experience indicates that the treatment is simple, safe, and effective.
The indications for two types of pulsed Nd: YAG lasers in the treatment of vitreous pathology are reviewed. A series of 94 eyes from 93 patients were treated with the mode-locked system and 72 eyes from 71 patients were treated with the Q-switched system. A classification of vitreous pathology with prognostic value for the efficacy of treatment of both lasers is established. For the Q-switched laser the range of indications in the posterior pole is larger and fewer sessions are needed; however, complications are more frequent than with the mode-locked laser. This difference is due to the higher energy needed with the Q-switched laser to treat more severe vitreous pathology.
Fifty-nine eyes underwent vitreous surgery (vitreolysis) with the Q-switched Nd: YAG laser. This was used to cut vitreoretinal bands and membranes in 16 eyes and to clear persistent vitreous opacities in 25 eyes. The use of appropriate specialized contact lenses and modification of the standard slit-lamp delivery system were essential for vitreous YAG laser surgery. Successful results occurred in eyes where the target tissues were located at distances greater than 2 mm from the crystalline lens and the retina. Vision was improved in 18 eyes, unchanged in 40 eyes, and worse in 1. Complications included focal opacities of the crystalline lens in 5 eyes, retinal holes with detachment in 1 eye, and minor retinal hemorrhages in 4. Methods of preventing complications are discussed.
We present an overview concerning the current status of photodisruptive methods used in the treatment of pathologic changes in the vitreous space. In one series of 320 cases studied, 65% of the planned dissections of pathologic structures were successful. In a second series of 34 more complicated cases, the success rate was even lower. Complications included 15 retinochoroidal hemorrhages and one damaged posterior lens capsule. When one compares optical-surgical methods with conventional methods, it is obvious that the former aim at achieving goals that are less ambitious than those of classic vitrectomy and, in many cases, serve only to prepare for - and facilitate - a classic vitrectomy. By definition, laser vitreolysis dissects, but cannot remove, the fragments of disrupted structures from the eyeball. However, despite the obvious risks, photodisruptive laser surgery is considered less dangerous than is classic vitrectomy because photodisruption is a “noninvasive” procedure. Since laser vitreolysis is able to solve a number of clinical problems, obviating the need for vitrectomy, the former procedure should receive increasing attention for the treatment of pathologic problems in the vitreous cavity.
A set of convex-surfaced contact lenses with radii of 12.5mm, 18mm, and 25mm has been developed for Nd:YAG laser work in the vitreous cavity. The lenses reduce the energy threshold for plasma formation and increase the safety of intraocular YAG laser use.
A total of 589 patients (369 women and 220 men, 123 of whom were less than 40 years old and 52 of whom were more than 70 years old) with photopsia, vitreous floaters, or both participated in a prospective study designed to identify patients at particularly high risk for retinal tears. The patients were graded on a number of factors before undergoing peripheral retinal examinations. Computer analysis showed that the following factors had the strongest associations (P less than .001) with retinal tears: visual symptoms of diffuse dots (62 of 120 patients, or 51.7%), many vitreous cells (graded 2+ or worse) (61 of 94 patients, or 64.9%), and grossly visible vitreous or preretinal blood (51 of 56 patients, or 91.1%). Of the 176 eyes that had at least one of these three conditions, 93 (52.8%) had retinal tears compared to 16 of the remaining 413 eyes (3.9%). Although other factors correlated with retinal tears to some degree, the associations were not strong enough to help select the high-risk group.
Ultrashort, Q-switched or mode-locked, neodymium-YAG laser pulses focused within 2 mm of the retina caused reproducible retinal damage in four eyes of two monkeys and in four eyes of three rabbits. The distance of the laser focus from the retina for clinically observed threshold retinal damage was characterized for pulse energies up to 9 mJ. For the 2-mJ to 6-mJ pulse energies necessary to rupture vitreal membranes in clear media in rabbits, the high-power laser pulses could not be focused within 2mm of the retina without substantial risk of damaging the underlying retina. These laser pulses did not rupture vitreal membranes in hazy ocular media that prevented precise focusing. The retinal damage was somewhat greater than expected for retinal absorption of 1.06-micron laser energy, suggesting that secondary effects such as self-focusing and shock waves emanating from the focus may be important.