Three hundred sixty-degree laser retinopexy (360°-LRP) is an essential element in the treatment of complicated retinal detachment. The incidence of retinal redetachment has been shown to be reduced more than twofold (from as high as 26% to 14%) [
The 360° laser retinopexy is most commonly performed at the end of the vitrectomy with the endolaser probe [
Various modifications of conventional postoperative 360°-LRP with a single-spot laser attached to indirect ophthalmoscope or slit-lamp are laborious (since they involve the application of numerous laser burns around the entire fundus periphery) and painful due to postoperative ocular irritation.
Currently, the need for massive laser photocoagulation sessions is satisfied by using the pattern laser photocoagulation techniques. The laser parameter range available with the navigated pattern technology contributes to decreased pain and duration of laser photocoagulation procedure [
The study purpose was to compare three 360°-LRP approaches (using navigated pattern laser system, single-spot slit-lamp laser delivery, and single-spot indirect ophthalmoscope laser delivery) in regard to (1) procedure duration, (2) procedural pain score, and (3) technical difficulties and the ability to achieve surgical goals.
The study was approved by the Ethics Committee of the Military Medical Academy and followed the tenets of the Declaration of Helsinki. All patients gave written informed consent both for participation in the study and for LRP.
Rhegmatogenous retinal detachment patients with clinical indications for laser retinopexy were included in this single-center prospective randomized longitudinal interventional study. LRP was indicated to prevent retinal redetachment after the surgical procedures specified in Table
Indications for postoperative laser retinopexy (and proportion of patients included in the study).
Indications for postoperative laser retinopexy | Number of cases | |||
---|---|---|---|---|
Pattern LRP | SL-LRP | IO-LRP | ||
(1) | Vitrectomy for rhegmatogenous retinal detachment (RRD) [ | 10 | 5 | 2 |
(2) | Silicone oil tamponade for RRD [ | 12 | 11 | 9 |
(3) | Circular scleral buckling for RRD [ | 14 | 12 | 11 |
LRP: laser retinopexy; SL-LRP: laser retinopexy using single-spot slit-lamp laser delivery; IO-LRP: laser retinopexy using single-spot indirect ophthalmoscope laser delivery.
Exclusion criteria were (1) incomplete performance of intraoperative LRP (excluding the cases when endolaser photocoagulation was applied outside the 360°-LRP site); (2) acute infections of the posterior segment; (3) postoperative inflammatory response; or (4) use of nonsteroidal anti-inflammatory, antihistamine, sedative, or other drugs which can potentially influence pain self-assessment.
Pattern laser retinopexy was performed using Navilas 532 laser system (OD-OS, Berlin, Germany) incorporating navigated Rapid PRP technology to produce 30 ms pulses, with square pattern from 3 × 3 to 5 × 5 laser spots (spot size, 450
Slit-lamp LRP (SL-LRP) was performed with the 532 nm GYC-1000 laser (NIDEK, Japan) attached to ophthalmic YAG laser system YC-1800 (NIDEK). A wide-field contact lens, Mainster PRP 165 (Ocular Instruments, Inc., Bellevue, WA) and/or G-3 Three-Mirror Glass Gonio Fundus Lens (Volk Optical, Inc., Mentor, OH) were used for laser delivery. Given the laser spot magnification of the lens, the actual retinal laser spot size was 350
Indirect ophthalmoscope LRP (IO-LRP) was performed with the binocular indirect ophthalmoscope NBO-3-01 (ZOMZ, Sergiev Posad, Russia) and 532 nm GYC-1000 laser (NIDEK). A 20-dioptre noncontact aspheric lens (Ocular Instruments) was used for laser delivery. Given the laser spot magnification of the lens, the actual retinal laser spot size was 800 to 1000
Patients were randomly assigned to the pattern LRP, SL-LRP, or IO-LRP.
Primary endpoints were amount of time needed for LRP, number of sessions, pain level, number of applied laser burns, and rate of surgical goal achievement. Retinal redetachment rate after silicone oil removal or after vitrectomy and/or buckling surgery was a secondary endpoint.
The procedural time was measured as the time that elapsed between the initial placement of the contact lens onto the eye (visualization of the fundus with the help of the 20-D aspheric lens in the IO-LRP group) and the final laser burn application, irrespective of the number of placements of the contact lens.
A session was defined as the LRP procedure performed during a patient’s visit to the clinic. At the end of each session, the ophthalmologist made a decision whether the next session was required. If the next session was required, the date was scheduled based on the cause of a failure to complete a 360°-LRP within the first session (cases requiring resorption of subretinal fluid or improvement in vitreous clarity were given increased session-to-session intervals compared to those with difficulties associated with apparent pain, narrow pupil, fibrosis of the capsular bag, or decentration of the intraocular lens).
The total number of laser spots delivered in each patient during all LRP sessions was determined after completion of each session.
The 4-point Verbal Rating Scale (VRS; 0, no pain; 1, mild pain; 2, moderate pain; and 3, severe pain) was used to self-assess the procedural pain immediately following the procedure, with the patient being explained that the pain sensation was caused not by mechanical effects of the lens, but by exposure to laser irradiation [
In each case, irrespective of the presence or absence of a tamponade of the vitreous cavity, the single surgical goal was to achieve either coagulation of the extreme and midperipheral fundus (with retinal tear photocoagulation) over 360 degrees or coagulation spread over the entire posterior slope of the buckle and anteriorly of it (with retinal tear photocoagulation) (Figure
(a) Fundus image of the patient with a circular scleral buckle (CSB) and a meridional scleral buckle for multiple retinal tears, after two LRP sessions, with the surgical goal fully achieved. (b) Fundus image of the patient with a CSB and silicone oil tamponade of the vitreous cavity, after a single “pattern LRP” session, with the surgical goal fully achieved (LRP at a single tear was performed intraoperatively).
Medical records were retrospectively reviewed to determine the times between the retinal detachment surgery and LRP separately for cases with and without silicone tamponade.
The technical difficulties encountered during each of the LRP session were assessed to explain the causes of possible difference in success rate of surgical goals among the study groups. Technical difficulty was defined as the presence of any condition (e.g., subretinal fluid and IOL decentration) hampering the placement and visual assessment of laser burns at a fundus site during its sequential photocoagulation in a clockwise fashion.
Patients underwent fundus examinations at week 2 (following either silicone oil removal from the vitreous cavity or LRP after vitrectomy and/or buckling surgery) and then every month thereafter to exclude retinal redetachment after LRP. Minimum follow-up time was 6 weeks (with 2 consecutive visits). The presence of subretinal fluid posteriorly of the laser coagulation area was considered as retinal redetachment and was checked visually; OCT was done in doubtful cases.
All data are presented as mean ± standard deviation. A one-way analysis of variance (ANOVA) with Bonferroni-adjusted post hoc comparisons was used to assess between-group differences in age and qualitative and quantitative characteristics of LRP. A chi-square test was used to assess between-group differences in male-to-female ratio, rate of surgical goal achievement, technical difficulty rate, and retinal redetachment rate.
Eighty-six individuals (44 men and 41 women) were included in the study. There was no statistically significant difference in age and male-to-female ratio among the groups (Table
Characteristics of the study population.
Pattern LRP | SL-LRP | IO-LRP | |
---|---|---|---|
Patients, total | 36 | 28 | 22 |
Age, years | 50.8 ± 8.8 | 61.9 ± 12.4 | 55.1 ± 11.0 |
Sex, male/female | 22/14 | 13/15 | 9/12 |
Patients with IOL | 22 | 17 | 16 |
LRP: laser retinopexy; SL-LRP: laser retinopexy using single-spot slit-lamp laser delivery; IO-LRP: laser retinopexy using single-spot indirect ophthalmoscope laser delivery.
In the pattern LRP group, the amount of time needed for LRP, number of sessions, and pain level were statistically significantly lower, whereas the number of applied laser burns was higher compared to those in the SL-LRP group and in the IO-LRP group (
Comparison of primary endpoints between pattern LRP, SL-LRP, and IO-LRP groups.
Pattern LRP | SL-LRP | IO-LRP | |
---|---|---|---|
Procedural time, minutes | 12.4 ± 5.4 | 21.7 ± 7.6 | 17.0 ± 10.1 |
Procedural pain score | 1.1 ± 0.5 | 1.8 ± 0.5 | 1.9 ± 0.5 |
Total number of laser burns applied | 1108.7 ± 345.5 | 714.5 ± 219.8 | 408.1 ± 95.5 |
Number of LRP sessions | 1.2 ± 0.4 | 2.0 ± 0.6 | 1.9 ± 0.7 |
Days after circular scleral buckling or vitrectomy | 2.0 ± 1.4 | 3.9 ± 3.1 | 2.4 ± 1.9 |
Days after initiation of tamponade | 119.8 ± 67.0 | 103.1 ± 54.3 | 88.5 ± 61.4 |
LRP: laser retinopexy; SL-LRP: laser retinopexy using single-spot slit-lamp laser delivery; IO-LRP: laser retinopexy using single-spot indirect ophthalmoscope laser delivery.
There was no statistically significant difference in mean time after retinal detachment surgery (in case of silicone oil tamponade, after silicone oil injection) among the groups (Table
In the pattern LRP group, technical difficulties were encountered in 18 cases (50.0%), with the most common difficulty being residual retinal detachment (11 cases), followed by the rigid pupil (which hampered visualization of the peripheral fundus; 5 cases), fibrosis of the capsular bag and/or decentered IOL (5 cases), irregularly placed CSB (anteriorly displaced; 2 cases), and media opacification (partial vitreous hemorrhage) early following retinal detachment surgery (1 case). The pattern LRP was aborted due to high pain levels in one patient.
In the SL-LRP group, technical difficulties occurred in 15 cases (53.6%) and included residual retinal detachment (6 cases), narrow and/or decentered pupil (5 cases), fibrosis of the capsular bag (2 cases), and posttraumatic corneal scar (1 case). In addition, the SL-LRP was aborted due to high pain levels and significant procedural time needed to fully achieve the surgical goal in 9 patients.
Technical difficulties were encountered in 12 cases (54.6%) of the IO-LRP group and included residual retinal detachment (5 cases), narrow pupil (4 cases), and fibrosis of the capsular bag and/or decentered IOL (3 cases). In addition, the IO-LRP was aborted due to high pain levels and significant procedural time needed to fully achieve the surgical goal in 5 patients.
There was no statistically significant difference in technical difficulty rate among the groups.
If a residual detachment was present at the extreme peripheral fundus, LRP was performed posterior of the detachment. These cases corresponded to “failure to achieve surgical goal.” Performing photocoagulation posterior of the area initially planned for photocoagulation was not included into the definition of the achievement of surgical goal, since it does not correspond to the definition of classical LRP.
In the pattern LRP group, failures to achieve surgical goals were associated with residual retinal detachment (9 patients) or narrow pupil with fibrosis of the capsular bag and decentration of the intraocular lens (3 patients). In the SL-LRP group, these failures were associated with residual retinal detachment (6 patients), narrow pupil and fibrosis of the capsular bag (4 patients), or corneal scar (1 patient). In the IO-LRP group, failures to achieve surgical goals were associated with residual retinal detachment (5 patients) or narrow pupil with fibrosis of the capsular bag and decentration of the intraocular lens (4 patients).
In the pattern LRP, SL-LRP, and IO-LRP groups, the mean duration of follow-up after silicone oil removal was
In the pattern LRP, SL-LRP, and IO-LRP groups, the mean duration of follow-up after vitrectomy and/or buckling surgery was
The present study shows that 360°-LRP performed using the navigated pattern laser (Navilas) is less time-consuming and less painful than that performed with a single-spot laser coupled with a slit-lamp or indirect ophthalmoscope laser delivery system. In addition, there was no statistically significant difference in rate of full achievement of the surgical goal and in retinal redetachment rate between the pattern LRP and conventional 360° LRP techniques. The absence of significant difference in goal achievement rate can be explained by similar number and configuration of the technical difficulties (e.g., rigid pupil and residual detachment) resulting from the anatomic status of the eye after retinal detachment surgery and hampering photocoagulation irrespective of the method of laser delivery. However, the rate of achievement of the surgical goal in the pattern LRP was higher than in comparison groups, although not statistically significantly.
The effect of 360° LRP (i.e., the reduction in the rate of postoperative retinal detachment) has been demonstrated for vitrectomy with and without silicone oil tamponade [
Sometimes postoperative, 360° LRP is not well enough tolerated by patients, since retinal photocoagulation itself is painful, and is done in the early postoperative period, thus potentially contributing to increased pain sensation (e.g., following lens contact with conjunctival sutures). However, postoperative LRP can be performed over 360° (in one or more sessions) as the subretinal fluid resolves, with no anesthetic except some topical. The use of a single-spot laser for 360° LRP is more time-consuming than other approaches, which affects tolerability of the procedure; unfortunately, there are no available data on the use of the navigated pattern laser technology for this purpose.
In the study presented, we found that the use of 360°-pattern LRP has the advantages of (1) reduced time required for achievement of the surgical goal due to reduced number and duration of LRP sessions and (2) less pain due to numerous short duration laser burns and reduced need for lens manipulation on the eye because of a wide field of view. Moreover, no additional technical difficulties were found, and the navigated pattern laser technology allows performing LRP in the amount as great as required and at any reasonable time after various retinal detachment surgeries.
We found this approach to postoperative 360°-LRP at least as effective as the two other approaches, with similar rate of redetachment in the early period after silicone oil removal. Moreover, the mean number of laser spots in postoperative 360°-pattern LRP was higher than those relevant to other methods, which can be explained by improved tolerability and treatment speed. The clinical significance of these differences in regard to prevention of retinal redetachment deserves further study.
The so-called Rapid PRP is a special feature of the navigated pattern laser (Navilas), and, with the laser pulse duration and separation as short as of 30 ms and 10 ms, respectively, the time required for the application of a 25-spot pattern is no more than 1 s, allowing to cut the laser treatment time (in panretinal laser photocoagulation) a half [
A limitation of this study is the absence of data for comparison of postoperative 360° pattern LRP and intraoperative 360° LRP, with the latter being a widely used typical procedure [
Potentially, the navigated pattern approach may be used not only for 360° LRP, but also for other versions of postoperative LRP, including the LRP at the retinal tear site in meridional or circular extrascleral buckling and the LRP under conditions of pneumatic retinopexy or short-term perfluorocarbon fluid tamponade.
In conclusion, the navigated pattern approach (Navilas) to 360° LRP (a) allows improving the treatment time and pain in postoperative 360° LRP and presents no technical difficulties additional to the conventional (slit-lamp or indirect ophthalmoscope) approaches with a single-spot laser and (b) is at least as effective in achieving the surgical goal as these approaches.
The authors have no proprietary or financial interest in any aspect of this report.
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors thank O. V. Oleksiienko for his assistance in translating the article.