Interventional procedure overview of YAG laser vitreolysis for symptomatic vitreous floaters

Analysis

Follow-up issues: All patients were followed for 6 months, except for 3 patients of the control group that were lost to follow up because of their dissatisfaction with the results. These 3 patients were excluded from the study. Patients were assessed at 30 minutes after the end of the laser session, and then 1 week, 1 month, 3 months and 6 months.

Study design issues: This prospective double-blind randomised clinical trial (RBR-2jq3v) compared the effects of vitreolysis with Nd:YAG laser for the treatment of vitreous opacities with a placebo procedure, analysing the symptoms reported by patients and signs observed by researchers. Primary outcomes were visual disturbance on a 10-point scale, changes in a 4-level symptom severity scale, contrast sensitivity measured with the Pelli-Robson chart and the NEI VFQ-25. Secondary results included objective change in vitreous opacities, BCVA, variation in IOP and adverse events.

Randomisation was done using a random number for each patient, 1 for intervention and 2 for placebo. Only 1 eye had the intervention (the eye to which the patient referred the most complaints) and the fellow eye was observed. All procedures were done by the same physician. Intention-to-treat analysis was not used.

A masked evaluator rated the fundus photography for the presence of floaters using the 4-level scale used by patients to report their postoperative symptoms compared with the baseline. The following percentages were used to quantify the level of improvement: 0% or worse; limited success, 30% to 50%; pronounced success, 50% to 70%; and total success, 100%.

Study population issues: At baseline, there were no statistically significant differences in age, sex, most symptomatic eye (left versus right), lens status (phakic versus pseudophakic), duration of symptoms and visual disturbance scale.

Analysis

Follow-up issues: Patients were clinically assessed at 30 minutes postoperatively and then at week 1, month 1, month 3 and month 6.

Study design issues: This single-centre, masked, sham-controlled randomised clinical trial (NCT02897583) evaluated YAG laser vitreolysis compared with sham vitreolysis for symptomatic Weiss ring floaters from PVD. Primary 6-month outcomes were subjective change in symptoms measured from 0% to 100% using a 10-point visual disturbance score, a 5-level scale, and the NEI VFQ-25. Secondary outcomes included objective change assessed by masked grading of colour fundus photography and ETDRS BCVA.

In all patients, 1 eye (the eye with the most patient-determined floater-related symptoms) was treated, and the other eye was observed. Patients were assigned to YAG and sham groups in a 2:1 ratio to maximise the number of treated patients and obtain more robust efficacy and safety data for YAG vitreolysis.

A priori sample calculations assumed a modest improvement in symptoms of 30% in the YAG group compared with 10% in the sham group, yielding a sample of 75 patients with an SD of 25%, α of .05, and power of 0.9. A planned interim analysis showed a statistically significant difference among the 13 patients who had completed the study. Thus, the decision was made to schedule no further screening visits beyond those already scheduled, resulting in 52 enrolled patients. This RCT was adequately powered.

One author did all the treatments. Another author graded the masked wide-angle photographs for the presence of floaters by using the 5-level scale used by patients to self-report their postoperative symptoms compared with baseline. The following percentages were used to quantify the level of improvement: worse, less than 0%; same, 0%; partial success, 30% to 50%; significant success, 50% to 70%; and complete success, 100%.

Study population issues: The mean duration of symptomatic floaters was 6.7 years (range, 0.5 to 63.0 years; median, 2.0 years) in the YAG group and 5.0 years (range, 0.5 to 30.0 years; median, 3 years) in the sham group.

Other issues: No adverse events judged to be of clinical relevance occurred after YAG laser vitreolysis in this small prospective study, which was underpowered to identify less common potential complications. This study included a small sample with a short follow-up period. The current study focused on comparing YAG vitreolysis with sham but not with vitrectomy. The study also allowed just 1 treatment session per patient to prevent unmasking. However, this strategy might not reflect real-world treatment, in which patients might be treated with additional YAG vitreolysis sessions for persistent floaters after initial treatment. Results from this study cannot be generalised to all patients with symptomatic floaters because only those with Weiss rings arising from PVD were treated.

Analysis

Study design issues: This study reported long-term complications and efficacy in patients enrolled in the randomised clinical trial (Shah 2017). Patients had the option of enrolling in an extension study if they received sham laser and wished to receive YAG vitreolysis treatment, or if they received YAG vitreolysis and had residual floaters that the treating surgeon felt could be treated. Therefore, patients in the previous sham group could access 1 or 2 YAG vitreolysis treatment sessions and patients in the previous YAG group could have a second or third treatment session.

All 52 patients were contacted and of these, 35 returned for this long-term observational visit. The primary outcome measures included subjective percentage of improvement (from 0% to 100%), 10-point visual disturbance score, 5-level qualitative scale and NEI VFQ-25. Secondary outcomes included objective change based on masked grading of colour wide-angle fundus photography, ETDRS BCVA, and adverse events.

Study population issues: Of the 35 patients, 27 patients were originally in the YAG vitreolysis arm and 8 patients were originally in the sham arm; 24 were phakic and 11 pseudophakic. In this cohort of 35 patients, 23 patients had a single YAG session, 11 had 2 sessions, and 1 patient had 3 sessions. One pseudophakic patient had worsening floaters and was treated with a pars plana vitrectomy. This patient was excluded in the analysis of the long-term follow-up cohort

Other issues: There were several weaknesses to this long-term follow-up study. There were no standardised guidelines dictating when additional YAG vitreolysis should be performed. There was no control arm followed to the final follow-up of this observational study, precluding the ability to calculate the inherent rate of symptomatic variation and adverse events over time in this population. Only Weiss ring floaters were included in this study; the results are unlikely transferrable to other floater types. Two important metrics, contrast sensitivity and reading speed, were not assessed during this study. Only 35 of the 52 patients enrolled in the initial randomised controlled trial voluntarily returned for the present long-term follow-up vision, allowing for the possibility of selection bias.

Analysis

Follow-up issues: Patients were followed up at 1, 3 and 6 months after the procedure.

Study design issues: This study evaluated and compared the subjective and objective efficacy of YAG laser vitreolysis for 2 types of primary symptomatic floaters (complete PVD type and non-PVD type) by comparing changes in questionnaire scores and objective visual quality measures before and after treatment. The main measures of objective visual quality were as follows: the Strehl ratio (SR), internal spherical aberration (SA), internal comatic aberration (CA), internal high order aberration (HOA) and area ratio of modulation transfer function (MTFa). All values were obtained at the 4-mm zone of pupil. The main subjective measures included VSFQ-13 and improvement in vitreous floaters using a 5-level scale. VFSQ-13 assessed symptoms related to vitreous floaters based on 6 parts of visual quality (distance activities, near activities, driving, social functioning, peripheral vision, and mental health) to determine whether the floaters were bothersome. The equivalent percentage of improvement was used: (1) worse: less than 0%; (2) the same: 0 to 30%; (3) partial success: 30% to 50%; (4) significant success: more than 50%; (5) complete success: 100%.

All procedures were done by an experienced retinal specialist (first author). During the 6-month follow-up period, all patients had YAG laser vitreolysis only once. After 6 months, rescue therapy with repeated YAG laser vitreolysis was possible, but the results were excluded from statistical analysis.

Study population issues: Of the 51 eyes with floaters, 29 (57%) were non-PVD type, and the rest were PVD type. At baseline, there were no statistically significantly differences between groups in age, gender, LogMAR BCVA, IOP, spherical equivalent, power of YAG laser and number of shots.

Other issues: There were several limitations in the study, including its small sample size, open design and short follow-up period as well as being a single-centre study and having no control group. Risk factors correlated with the poor outcomes of laser vitreolysis was not analysed because of the small sample.

Analysis

Study design issues: This study described the treatment efficacy of Nd:YAG on vitreous floaters by evaluating the changes of floater area in fundus infrared imaging. Subjective evaluation included NEI VFQ-25 and symptom improvement on a 4-level scale: failure, floaters were the same or worse (0% to 30%); partial success, some improvement but still floaters of moderate inconvenience (31% to 70%); significant success, significant improvement with only slight inconvenience (71% to 99%); complete success, complete resolution of floaters (100%). Objective evaluation covered IOP, visual acuity, and floater areas calculated using Image J software. YAG vitreolysis was done by the same physician.

Study population issues: At baseline, patients reported intolerable floaters for 14.6±6.2 months before resorting to YAG laser treatments. Of 50 patients, 28 (56%) reported that reading activities were mostly affected by floaters, 20 (40%) for driving and one half of the patients complained the bothersome floaters all the time. Symptomatic severity of the bothersome floaters was evaluated based on the life inconvenience of patients and the IR imaging. Seventeen (30.91%) eyes were considered as severe, 21 (38.18%) were moderate, and the remaining 17 (30.91%) eyes were mild. Physically aging (n=15), PVD (n=21), and high myopia (n=13) were significant causes of floaters. The preoperative intraocular pressure was 15.71 ± 2.4 mmHg, and all study eyes had normal IOP.

Analysis

Follow-up issues: Patients were followed up at day 1 and week 1 after the first session of laser treatment. After 1 month, every patient had a second session. They were then followed up at days 1 and 10.

Study design issues: This pre and post-test study assessed the quality of life in patients treated with Nd:YAG laser for symptomatic floaters. Health-related quality of life of the patients was measured before and after the intervention with VFQ-25 and VFQ-39. Anxiety level was measured with STAI. Visual acuity, contrast sensitivity, and safety parameters were also considered. All patients were treated by the same medical team using the same treatment and post-treatment protocol.

Study population issues: At baseline, the percentage of frequent drivers was 67.6% and 88.2% used electronic devices daily. The mean duration of symptoms was 2.5 years (SD 3.67), with patients having had more than 2 previous consultations for vitreous floaters.

Analysis

Follow-up issues: Patients were assessed at 1-week, 2-week, 1-month, and 6-month follow ups.

Study design issues: This double-centre, interventional and prospective study evaluated the efficacy and safety of YAG laser vitreolysis in patients with symptomatic vitreous floaters, using the colour fundus imaging objective assessment and the subjective information from NEI VFQ-25. The colour fundus photographs were graded for the presence of floaters using a 5-level scale: worse (less than 0%), same (0%), partial improvement (30% to 50%), significant improvement (50% to 70%), and complete improvement (100%).

The primary outcomes were objective and subjective changes measured by masked grading of colour fundus photographs and self-reported percentage of vitreous floaters improvement, and the near and distance activities subscale of the NEI VFQ-25. Secondary outcomes included ETDRS BCVA and adverse events. All laser treatments were done by the same surgeon (first author).

Study population issues: Patients had prepapillary (single membranous ring-shaped opacities or Weiss ring) and/or central (discrete and fibrous opacities floating freely around the centre of the vitreous cavity) vitreous opacities.

Other issues: This study included a small sample which was underpowered to identify less common potential complications.

Analysis

Study design issues: This retrospective assessment analysed cases of complications following laser vitreolysis as voluntarily reported to the American Society of Retina Specialists Research and Safety in Therapeutics Committee, an independent task force formed to monitor device-related and drug-related safety events, during a 6-month period.

Study population issues: Of the 15 patients, 14 patients were treated with laser vitreolysis by a comprehensive ophthalmologist and 1 patient by a retina specialist. In 14 patients, a single complication was reported, whereas in 1 patient, both glaucoma and a retinal tear were reported.

Other issues: The authors stated that this collection of reported complications, although robust, was likely underreported and not comprehensive. This type of analysis could not estimate complication rates or their relative frequencies. Nearly all reported complications were submitted by physicians other than the treating clinician, suggesting underreporting in one's own patients.