Time course of changes in aqueous flare intensity after vitrectomy for rhegmatogenous retinal detachment

Risk factors for proliferative vitreoretinopathy after retinal detachment surgery: A systematic review and meta-analysis

BACKGROUND

To comprehensively investigate risk factors for proliferative vitreoretinopathy (PVR) after retinal detachment (RD) surgery.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were systematically searched until May 22, 2023. Risk factors included demographic and disease-related risk factors. Odds ratios (ORs) and weighted mean differences (WMDs) were used as the effect sizes, and shown with 95% confidence intervals (CIs). Sensitivity analysis was conducted. The protocol was registered with PROSPERO (CRD42022378652).

RESULTS

Twenty-two studies of 13,875 subjects were included in this systematic review and meta-analysis. Increased age was associated with a higher risk of postoperative PVR (pooled WMD = 3.98, 95%CI: 0.21, 7.75, P = 0.038). Smokers had a higher risk of postoperative PVR than non-smokers (pooled OR = 5.07, 95%CI: 2.21-11.61, P<0.001). Presence of preoperative PVR was associated with a greater risk of postoperative PVR (pooled OR = 22.28, 95%CI: 2.54, 195.31, P = 0.005). Presence of vitreous hemorrhage was associated with a greater risk of postoperative PVR (pooled OR = 4.12, 95%CI: 1.62, 10.50, P = 0.003). Individuals with aphakia or pseudophakia had an increased risk of postoperative PVR in contrast to those without (pooled OR = 1.41, 95%CI: 1.02, 1.95, P = 0.040). The risk of postoperative PVR was higher among patients with macula off versus those with macula on (pooled OR = 1.85, 95%CI: 1.24, 2.74, P = 0.002). Extent of RD in patients with postoperative PVR was larger than that in patients without (pooled WMD = 0.31, 95%CI: 0.02, 0.59, P = 0.036). Patients with postoperative PVR had longer duration of RD symptoms than those without (pooled WMD = 10.36, 95%CI: 2.29, 18.43, P = 0.012).

CONCLUSION

Age, smoking, preoperative PVR, vitreous hemorrhage, aphakia or pseudophakia, macula off, extent of RD, and duration of RD symptoms were risk factors for postoperative PVR in patients undergoing RD surgery, which may help better identify high-risk patients, and provide timely interventions.

Association between blood-aqueous barrier disruption and extent of retinal detachment

PURPOSE

To investigate the association between anatomical features of rhegmatogenous retinal detachment (RRD) and the extent of blood-aqueous barrier disorder measured by non-invasiv laser flare photometry.

METHODS

Retrospective evaluation of consecutive patients with RRD that underwent surgery between November 2016 and October 2018. Descriptive evaluation of pre- and postoperative parameters and correlation to preoperative laser flare value, extent of retinal detachment and re-detachment rate were performed.

RESULTS

266 patients (mean age 62.73 ± 10.40 years, 62.8% male) were included. Mean preoperative flare value was 11.0 ± 11.9 pc/ms. In pseudophakia flare values were higher than in phakia (12.7 ± 10.4 pc/ms versus 9.8 ± 12.9 pc/ms; p = 0.042). Flare increased and correlated significantly with the number of affected retinal quadrants (Q) (1 Q 6.4 ± 3.3 pc/ms; 2 Q 10.5 ± 8.8 pc/ms; 3 Q 15.6 ± 9.1 pc/ms; 4 Q 27.5 ± 33.3 pc/ms; p < 0.001; r = 0.40). Macular status correlated significantly with flare values (macula on 8.6 ± 7.1 pc/ms, off 13.1 ± 15.0 pc/ms; p = 0.004; r = 0.17).

CONCLUSION

The level of objective tyndallometry in RRD seems to be influenced by lens status and extent of retinal detachment. Thus, the greater the affected retinal area is, the more blood-aqueous barrier disruption seems to be present.

Association between laser flare photometry and symptom duration in primary rhegmatogenous retinal detachment

PURPOSE

The purpose of this study was to investigate preoperative blood-ocular barrier disruption via laser flare photometry (LFP) in patients diagnosed with rhegmatogenous retinal detachment (RRD), and to analyse possible associations with symptom duration and anatomical parameters.

METHODS

We retrospectively analysed consecutive patients presenting with RRD at a single centre between January 2016 and March 2020. LFP was performed in both eyes after pupillary dilatation prior to RRD surgery. Symptom duration, extent of retinal detachment, and lens status were assessed. For statistical analysis, we carried out the unequal variances t test and Welch's analysis of variance (ANOVA).

RESULTS

We included 373 eyes of 373 patients (mean age 63.96 years ± 10.29; female:male ratio 1:1.8). LFP values quantified in photon count per millisecond (pc/ms) increased with longer symptom duration when comparing patients with a symptom duration of 0-3 days (n = 158; 9.25 ± 6.21 pc/ms) and ≥ 4 days (n = 215; 11.97 ± 11.58 pc/ms; p = 0.004). LFP values also rose with the number of retinal quadrants affected by RRD (1 quadrant, 6.82 ± 4.08 pc/ms; 2 quadrants, 10.08 ± 7.28 pc/ms; 3 quadrants, 12.79 ± 7.9 pc/ms; 4 quadrants, 31.57 ± 21.27 pc/ms; p < 0.001), macula off status (macula on, 8.89 ± 6.75 pc/ms; macula off, 12.65 ± 11.66 pc/ms; p < 0.001), and pseudophakic lens status (pseudophakia, 12.86 ± 9.52 pc/ms; phakia: 9.31 ± 9.67 pc/ms; p < 0.001).

CONCLUSION

In RRD patients, blood-ocular barrier disruption quantified by LFP is associated with the duration of symptoms and the disease's anatomical extent. These results warrant further investigation of the potential clinical use of LFP in RRD.

Corneal shape changes after vitreoretinal surgery with fluid-gas exchange

To investigate changes in the corneal shape caused by fluid-gas exchange after vitrectomy.This retrospective case-control study included 43 eyes that underwent a combination of cataract surgery and vitrectomy. The corneal shape was measured using anterior segment optical coherence tomography CASIA2. The corneal shape measurements were performed preoperatively, 1 day, 1 week, 1 month, and 3 months after surgery. After calculating the real K value from the actual measured values of the posterior shape of the corneal refracting power and the single posterior corneal refracting power value, Fourier analysis values were examined. Fluid-gas exchange was performed in 23 eyes (gas group), while it was not performed in 20 eyes (nongas group).There was a significant increase in the real K value in the regular and asymmetry components (0.61 ± 0.36, 0.82 ± 0.64) in the gas group only on the first day after surgery (Steel-Dwass test; P < .05). There was also a significant increase in the real K value in the higher-order irregular astigmatism components (Steel-Dwass test; P < .05) for longer periods in the gas versus the nongas group. The shape of the posterior cornea increased in all components in the gas group on the first day after surgery (spherical power -6.35 ± 0.20, regular astigmatism 0.32 ± 0.12, asymmetry 0.22 ± 0.13, and higher-order irregular astigmatism 0.12 ± 0.05, Steel-Dwass test; P < .05).Postoperative changes caused by surgical invasion in the corneal shape appeared to be greater in the gas versus the nongas group, in addition to affecting the time periods of the postoperative corneal shape changes.

Clinical factors contributing to postoperative aqueous flare intensity after 27-gauge pars plana vitrectomy for the primary rhegmatogenous retinal detachment

PURPOSE

To investigate the perioperative clinical factors, which contribute to the postsurgical aqueous flare intensity (AFI) following 27-gauge pars plana vitrectomy (27GPPV) for primary rhegmatogenous retinal detachment (RRD).

STUDY DESIGN

Retrospective clinical study.

METHODS

We performed retrospective analyses of the medical records of 47 eyes of 47 patients with primary RRD who had undergone 27GPPV with a wide-angle viewing system. AFI was measured preoperatively and 1 week, 1 month, 3 months, 6 months, and 12 months after the surgery.

RESULTS

AFI was significantly increased 1 week after the surgery (p<0.01) and then decreased overtime. At 6 months after surgery it was still statistically significantly higher than preoperative AFI (p=0.03). There was no statistical difference between preoperative AFI and that at 12 months following surgery. Multiple regression analyses revealed that the number of retinal photocoagulations and the performance of scleral indentation had significant positive correlation with AFI at 1 week, 1 month, 3 months, and 6 months, and at 1 month and 3 months after the surgery, respectively.

CONCLUSION

Intraoperative retinal photocoagulation and scleral indentation are probable causes of increased AFI after 27G PPV for RRD.

Application of Laser Flare Photometry in the Quantification of Blood-Aqueous Barrier Breakdown after Micro-incision Vitrectomy

Purpose: The purpose of the study is to quantify aqueous flare using laser flare photometry (LFM) in patients undergoing 25-G pars plana vitrectomy (PPV) and assess the need for postoperative topical corticosteroid administration . Methods: Prospective evaluation of 50 eyes (50 patients) was performed using LFM until day 30 postoperative. Duration of surgery, indication of PPV, and use of laser and/or cryotherapy were noted. Topical corticosteroids were used if mean LFM values were >50, or if there was anterior chamber fibrin. Results: Mean age of the subjects was 48.62 ± 10.07 years. The preoperative LFM value for 50 subjects was 17.42 ± 25.20. Topical corticosteroids were initiated in only 22 patients. The LFM values of subjects were not different from baseline at 1 month whether or not the subjects received corticosteroids (p > 0.106). Conclusions: With 25-G PPV, there is minimal breakdown of blood-aqueous barrier. LFM helps in monitoring postoperative inflammation, obviating the need for topical corticosteroids in significant number of patients.

Quantitative Assessment of Aqueous Flare After Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy

PURPOSE

To assess aqueous flare as a measure of subclinical inflammation after Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy.

METHODS

In this prospective cross-sectional and longitudinal case series at a tertiary referral center, 173 DMEK eyes of 169 patients and 19 age-matched healthy control eyes were included. Aqueous flare [photon count per millisecond (ph/ms)] was assessed by laser flare photometry at 1 day, 1 week, and 1 month after DMEK in group I (evaluation of postsurgical blood-aqueous barrier recovery; n = 25) and on average 28 (±19) months (range, 3-86 months) after DMEK in group II (evaluation of long-term inflammation; n = 148).

RESULTS

In group I, flare levels decreased from 1 day to 1 week [25.1 (±9.1) ph/ms vs. 13.4 (±4.8) ph/ms; P = 0.003] and remained stable up to 1 month after DMEK [12.1 (±3.2) ph/ms; P = 0.387]. However, average flare at 1 month was higher than that in healthy controls (P < 0.001). The long-term flare value after DMEK (group II) was 9.6 (±4.2) ph/ms and was higher in eyes associated with allograft rejection (n = 6) versus those without rejection [16.7 (±7.8) ph/ms vs. 9.3 (±3.8) ph/ms, respectively, P < 0.001]. All eyes associated with rejection had flare values above 10 ph/ms.

CONCLUSIONS

Aqueous flare after DMEK quickly decreased within the first postoperative month, indicating fast recovery of the blood-aqueous barrier. Long-term flare levels were higher in eyes associated with rejection, suggesting persistent subclinical inflammation. A flare level above 10 ph/ms may be used as a threshold for identifying eyes associated with or at risk of allograft rejection after DMEK.

Postoperative aqueous humour flare as a surrogate marker for proliferative vitreoretinopathy development

PURPOSE

As some surgical procedures have been shown to increase postoperative flare values and thus contribute to blood-ocular barrier breakdown, retinal reattachment surgery might influence the risk of developing proliferative vitreoretinopathy (PVR). Therefore, we investigated whether postoperative aqueous flare values are a surrogate marker for the development of postoperative PVR.

METHODS

We prospectively included 195 patients with primary rhegmatogenous retinal detachment (RRD) and measured aqueous laser flare preoperatively, and at 2 and 6 weeks postoperatively. Postoperative PVR was defined as reoperation for redetachment due to PVR membranes, within 6 months of initial surgery. Logistic regression and receiver operating characteristic (ROC) analysis determined whether higher postoperative flare values were associated with an increased risk of developing PVR later on.

RESULTS

Reoperation for postoperative PVR was needed in 12 (6.2%) patients; in 18 (9.2%), reoperation was not related to PVR. The median flare value for patients who would develop PVR was significantly higher than that of patients who would not develop PVR, both at 2 weeks (p = 0.001) and 6 weeks (p < 0.001) postoperatively. Logistic regression analyses showed that a higher flare value significantly increased the odds of developing PVR, either at 2 weeks [odds ratio (OR) 1.027; 95% CI: 1.010-1.044] or 6 weeks (OR 1.076; 95% CI: 1.038-1.115).

CONCLUSION

Flare values both at 2 and 6 weeks postoperatively seem a good surrogate marker in terms of sensitivity and specificity for the development of postoperative PVR but have only a modest positive predictive value. The 2-week value would be more useful in terms of early recognition of high-risk patients and hence give the possibility to better study effects of treatment methods.

Safety and Long-Term Efficacy of AAV4 Gene Therapy in Patients with RPE65 Leber Congenital Amaurosis

The aim of this study was the evaluation of the safety and efficacy of unilateral subretinal injection of the adeno-associated vector (AAV) serotypes 2 and 4 (AAV2/4) RPE65-RPE65 vector in patients with Leber congenital amaurosis (LCA) associated with RPE65 gene deficiency. We evaluated ocular and general tolerance and visual function up to 1 year after vector administration in the most severely affected eye in nine patients with retinal degeneration associated with mutations in the RPE65 gene. Patients received either low (1.22 × 10¹⁰ to 2 × 10¹⁰ vector genomes [vg]) or high (between 3.27 × 10¹⁰ and 4.8 × 10¹⁰ vg) vector doses. An ancillary study, in which six of the original nine patients participated, extended the follow-up period to 2-3.5 years. All patients showed good ophthalmological and general tolerance to the rAAV2/4-RPE65-RPE65 vector. We observed a trend toward improved visual acuity in patients with nystagmus, stabilization and improvement of the visual field, and cortical activation along visual pathways during fMRI analysis. OCT analysis after vector administration revealed no retinal thinning, except in cases of macular detachment. Our findings show that the rAAV2/4.RPE65.RPE65 vector was well tolerated in nine patients with RPE65-associated LCA. Efficacy parameters varied between patients during follow-up.

Management of postoperative inflammation after cataract and complex ocular surgeries: a systematic review and Delphi survey

Prevention and management of postoperative ocular inflammation with corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs) have been evaluated in several randomised controlled trials (RCTs). However, neither consensus regarding the efficacies of different regimens nor established guidelines are currently available. This has resulted in different practice patterns throughout the world. A systematic literature review found that for the management of postcataract inflammation nepafenac produced a positive outcome in three of three RCTs (3/3), as did ketorolac (1/1), bromfenac (7/7), loteprednol (3/3) and difluprednate (6/6), but not flurbiprofen (0/1). A single study found that betamethasone produced inconclusive results after retinal detachment (RD) surgery; ketorolac was effective (1/1) after vitrectomy, but triamcinolone was ineffective (0/1) after trabeculectomy. A two-round Delphi survey asked 28 international experts to rate both the inflammatory potential of different eye surgeries and their agreement with different treatment protocols. They rated trabeculectomy, RD surgery and combined phacovitrectomy as more inflammatory than cataract surgery. Vitrectomies for macular hole or epiretinal membrane were not deemed more inflammatory than cataract surgery. For trabeculectomy, they preferred to treat longer than for cataract surgery (NSAID + corticosteroid three times a day for 2 months vs 1 month). For vitrectomy alone, RD surgery and combined phacovitrectomy, the panel preferred the same treatment as for cataract surgery (NSAID + corticosteroid three times a day for 1 month). The discrepancy between preferred treatment and perception of the eye's inflammatory status by the experts for RD and combined vitreoretinal surgeries highlights the need for RCTs to establish treatment guidelines.

Validity of aqueous flare measurement in predicting proliferative vitreoretinopathy in patients with rhegmatogenous retinal detachment

PURPOSE

To investigate aqueous flare as a preoperative predictor for later proliferative vitreoretinopathy (PVR) development in patients with rhegmatogenous retinal detachment (RD) and to determine the validity of this measurement in patients at low clinical risk for postoperative PVR.

METHODS

This study included 100 eyes of 100 patients who underwent surgery for primary RD. Aqueous flare was determined preoperatively with a laser flare-cell meter (Kowa FM-500, Kowa Company Ltd, Tokyo, Japan). Patients were followed for at least 6 months postoperatively. Failures related to PVR were recorded for statistical analysis.

RESULTS

Twenty eyes (20%) developed PVR postoperatively. Preoperative flare values in these eyes were significantly higher than in eyes with no redetachment (48.12 ± 61.24 versus 17.74 ± 29.63 photon counts per millisecond (pc/ms), p = 0.002). The odds ratio for PVR development with flare values >15 pc/ms was 12.3 (p < 0.0001, 95% confidence interval, 3.54-42.59). Of 54 eyes at low clinical risk for postoperative PVR, five developed PVR postoperatively. Flare values were significantly higher in these eyes (25.30 ± 7.10 pc/ms) than in eyes with no redetachment (12.44 ± 10.16 pc/ms, p = 0.008). Using logistic regression, the odds ratio of PVR redetachment risk increased by the factor 1.078 per 1 pc/ms of flare value (95% CI, 1.01-1.15).

CONCLUSION

Preoperative aqueous flare is a strong predictive factor for PVR redetachment. The laser flare-cell meter provides a fast and safe tool to accurately identify patients at risk for postoperative PVR, especially when clinical examination did not predict this risk.

Preoperative aqueous humour flare values do not predict proliferative vitreoretinopathy in patients with rhegmatogenous retinal detachment

BACKGROUND/AIMS

Patients with rhegmatogenous retinal detachment (RRD) who develop postoperative proliferative vitreoretinopathy (PVR) have been found to have higher preoperative laser flare values than patients with RRD who do not develop this complication. Measurement of laser flare has therefore been proposed as an objective, rapid and non-invasive method for identifying high-risk patients. The purpose of our study was to validate the use of preoperative flare values as a predictor of PVR risk in two additional patient cohorts, and to confirm the sensitivity and specificity of this method for identifying high-risk patients.

METHODS

We combined data from two independent prospective studies: centre 1 (120 patients) and centre 2 (194 patients). Preoperative aqueous humour flare was measured with a Kowa FM-500 Laser Flare Meter. PVR was defined as redetachment due to the formation of traction membranes that required reoperation within 6 months of initial surgery. Logistic regression and receiver operating characteristic analysis determined whether higher preoperative flare values were associated with an increased risk of postoperative PVR.

RESULTS

PVR redetachment developed in 21/314 patients (6.7%). Median flare values differed significantly between centres, therefore analyses were done separately. Logistic regression showed a small but statistically significant increase in odds with increasing flare only for centre 2 (OR 1.014; p=0.005). Areas under the receiver operating characteristic showed low sensitivity and specificity: centre 1, 0.634 (95% CI 0.440 to 0.829) and centre 2, 0.731 (95% CI 0.598 to 0.865).

CONCLUSIONS

Preoperative laser flare measurements are inaccurate in discriminating between those patients with RRD at high and low risk of developing PVR.

Comparative study of 27-gauge vs 25-gauge vitrectomy for epiretinal membrane

PURPOSE

The purpose of this study was to compare 27-gauge (27G) with 25-gauge (25G) microincision vitrectomy in patients with epiretinal membrane (ERM).ParticipantsSeventy-four eyes of 66 patients undergoing 3-port pars plana vitrectomy using 27G or 25G instrumentation.

METHODS

Seventy-four eyes of 66 patients with ERM, who underwent 27G or 25G microincision vitrectomy were prospectively evaluated.

RESULTS

The mean operation time for vitrectomy was significantly longer in the 27G group than in the 25G group (9.9±3.5 vs 6.2±2.7 min, respectively, P<0.0001). No statistically significant difference was found between the two groups in terms of the mean operation time for ERM-inner limiting membrane peeling (27G vs 25G: 20.2±9.9 vs 16.1±9.3 min, P=0.14), although the time for vitreous cutting was longer in the 27G group (9.9±3.5 vs 6.2±2.7 min, respectively, P<0.0001). The flare value, intraocular pressure (IOP), and rate of hypotony 1 day after surgery did not differ between the 27G and 25G groups (flare value: 18.7 vs 17.2; IOP: 8.8 vs 9.7 mm Hg; rate of hypotony: 30 vs 35%, respectively). There was no significant difference in the surgically induced astigmatism between the two groups in the follow-up period. The mean time required for wound closure did not show a significant difference between the 27G and 25G groups (7.7 vs 8.6 weeks, respectively).

CONCLUSION

The 27G system is as safe and useful for ERM vitrectomy as the 25G system. Based on its potential, further improvement of 27G instruments could result in greater efficiency.

Short Pulse Duration High-Power Laser Photocoagulation during Vitrectomy for Diabetic Retinopathy Reduces Postoperative Inflammation

The aim of this preliminary study was to determine the effectiveness of short pulse duration, high-power laser photocoagulation (PC) during vitrectomy for diabetic retinopathy (DR).The effects of short pulse duration PC with power of 340-360 mW and duration of 0.02 second were compared to conventional PC with power of 120-150 mW and duration of 0.2 second. The degree of inflammation was quantified by laser flare cell photometry before and at 1 day, 1 week, 4 week, and 12 weeks postoperatively. Twenty-two eyes of 22 consecutive patients were studied. Ten eyes were treated with short pulse duration PC and 12 eyes with conventional PC. The total energy was significantly lower in the short pulse duration PC group than in the conventional PC group (P = 0.007). The flare cell values were not significantly different between the two groups after 1 day, but at 1 week, the flare cell value was significantly lower in the short pulse duration PC group than in the conventional PC group (P = 0.04). This difference was also present at 4 and 12 weeks (P<0.05). The significant lower inflammation after short pulse duration PC than conventional PC indicates that the short pulse duration PC protocol should be considered to treat DR.

Changes in contrast sensitivity after surgery for macula-on rhegmatogenous retinal detachment

PURPOSE

To evaluate changes in contrast sensitivity after surgery for macula-on rhegmatogenous retinal detachment (RRD).

DESIGN

Prospective, interventional, consecutive, case-control study.

METHODS

This study included 84 eyes of 84 patients with unilateral macula-on RRD undergoing primary scleral buckling or vitrectomy without postoperative macular complication. We examined the logarithm of the minimal angle of resolution best-corrected visual acuity (logMAR BCVA) and contrast sensitivity at 4 spatial frequencies (3, 6, 12, and 18 cycles/degree) using the CSV-1000E (Vector Vision) before and after surgery. From the data obtained with the CSV-1000E, the area under the log contrast sensitivity function was calculated. The logMAR BCVA and contrast sensitivity in the contralateral normal eyes also were measured and were used as normal controls. Clinical data were collected, including age, gender, surgical procedures, the number of retinal tears, circumferential dimension of retinal tears, and area of retinal detachment, to determine the clinical factors related to visual function.

RESULTS

Preoperative contrast sensitivity was significantly worse in eyes with RRD than in normal controls, but the preoperative logMAR BCVA was not different from that of normal controls. Contrast sensitivity decreased significantly after surgery, but logMAR BCVA did not change by surgery. Multiple regression analysis revealed that postoperative contrast sensitivity had a significant correlation with the circumferential dimension of retinal tears, whereas no clinical parameters were associated significantly with postoperative BCVA.

CONCLUSIONS

Surgery for macula-on RRD did not change visual acuity, whereas contrast sensitivity was affected significantly in association with the extent of retinal tears.