Bilateral patching in retinal detachment: fluid mechanics and retinal "settling"

BILATERAL EYE PATCHING MAY IMPROVE CLINICAL OUTCOMES FOR ACUTE PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT

PURPOSE

Evaluate preoperative bilateral eye patching (BEP) on subretinal fluid and vision in acute primary rhegmatogenous retinal detachments (RRDs).

METHODS

Retrospective nonrandomized interventional study of 335 patients with RRD undergoing BEP until surgery (BEP cohort) and separated by the percentage of full-time compliance: high (≥90%), medium (>90% but ≥50%), and low (<50%). Those declining BEP were included (control). All underwent surgery and were followed for ≥3 months. Imaging was obtained immediately before surgery. Best-corrected visual acuity was measured at the longest follow-up and immediately before surgery. SRF and foveal status immediately before surgery were analyzed.

RESULTS

Two hundred and forty and 95 patients were in BEP and control cohorts, respectively. Thirty patients presented immediately before surgery for analysis. High (64%) and medium (35%) compliance showed significantly greater ( P < 0.01) SRF reduction compared with low (4%) and control (3%). Mac-off RRD showed significantly greater ( P < 0.01) foveal reattachment with high (29%) and medium (8%) compliance compared with low (2%) and control (1%). Mac-on RRD demonstrated no significant differences ( P ≥ 0.51) in final best-corrected visual acuity among high (0 logarithm of the minimum angle of resolution [logMAR] [median], 20/20 Snellen), medium (0.10 logMAR, 20/25 Snellen), low (0.10 logMAR), and control cohorts (0.10 logMAR). Mac-off RRD demonstrated significantly better final best-corrected visual acuity with high compliance (0.30 logMAR, 20/40 Snellen) compared with low (0.40 logMAR, 20/50 Snellen; P = 0.04) and control (0.60 logMAR, 20/80 Snellen; P = 0.02).

CONCLUSION

Preoperative BEP can stabilize or improve subretinal fluid in acute primary RRD. Patients with BEP >50% of the time experienced the greatest benefits.

Computational Modeling of Ophthalmic Procedures: Computational Modeling of Ophthalmic Procedures

PURPOSE

To explore how finite-element calculations can continue to contribute to diverse problems in ophthalmology and vision science, we describe our recent work on modeling the force on the peripheral retina in intravitreal injections and how that force increases with shorter, smaller gauge needles. We also present a calculation that determines the location and stress on a retinal pigment epithelial detachment during an intravitreal injection, the possibility that stress induced by the injection can lead to a tear of the retinal pigment epithelium.

BACKGROUND

Advanced computational models can provide a critical insight into the underlying physics in many surgical procedures, which may not be intuitive.

METHODS

The simulations were implemented using COMSOL Multiphysics. We compared the monkey retinal adhesive force of 18 Pa with the results of this study to quantify the maximum retinal stress that occurs during intravitreal injections.

CONCLUSIONS

Currently used 30-gauge needles produce stress on the retina during intravitreal injections that is only slightly below the limit that can create retinal tears. As retina specialists attempt to use smaller needles, the risk of complications may increase. In addition, we find that during an intravitreal injection, the stress on the retina in a pigment epithelial detachment occurs at the edge of the detachment (found clinically), and the stress is sufficient to tear the retina. These findings may guide physicians in future clinical research. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

The Influence of Prolongation of Interruptions of Preoperative Posturing and Other Clinical Factors on the Progress of Macula-On Retinal Detachment

PURPOSE

To evaluate whether prolongation of interruptions of preoperative posturing by sitting upright influences retinal detachment (RD) progression. The secondary objective was to find clinical factors to identify patients with a high risk for RD progression.

DESIGN

Prospective cohort study.

PARTICIPANTS

One hundred ninety-eight patients divided among 3 cohorts of patients with macula-on RD were included. Inclusion criteria were volume OCT scans of sufficient quality and smallest distance from the fovea to the detachment border of at least 1.25 mm. In the second and third cohort, 50 patients with only superior temporal RD were included.

METHODS

Patients were admitted to the ward in anticipation of surgery. Preoperative bed rest and positioning were prescribed. The position of the RD border was determined based on OCT imaging performed at baseline, before and after the usual interruptions for meals or toilet visits. The duration of interruptions was prolonged with sitting upright for 20 minutes in cohort 2 and for 40 minutes in cohort 3. Various secondary outcome measures were defined, such as the baseline area of subretinal fluid (SRF) as measured on ultrasound images in the third cohort.

MAIN OUTCOME MEASURES

The RD border displacement was determined. The worst RD progression from baseline was given by the shortest distance to the fovea in any of the OCT scans during follow-up. The worst relative RD progression from baseline was defined as the worst RD progression from baseline as a percentage of the baseline distance between RD border and fovea.

RESULTS

The median duration of interruptions was 22, 41, and 58 minutes in cohorts 1, 2, and 3, respectively. The median RD border displacement during interruptions in patients with superior temporal RD was not significantly different among the cohorts (P = 0.28). The correlation coefficient between the SRF area at baseline and worst relative RD progression from baseline was 0.37 (95% confidence interval, 0.04-0.66; P = 0.009).

CONCLUSIONS

We did not find a significant increase in RD progression after prolongation of interruptions by sitting upright. Patients with a larger area of SRF on ultrasound showed more RD progression from baseline.

The Effect of Compliance With Preoperative Posturing Advice and Head Movements on the Progression of Macula-On Retinal Detachment

Purpose

The aim of this study was to explore the relationship between compliance with preoperative posturing advice and progression of macula-on retinal detachment (RD) and to evaluate whether head positioning or head motility contributes most to RD progression.

Methods

Sixteen patients with macula-on RD were enrolled, admitted to the ward, and instructed to posture preoperatively. The primary outcome parameter was compliance, which was defined as the average head orientation deviation from advised positioning. Secondary outcome parameters included the average rotational and linear head acceleration. The head orientation and acceleration were measured with a head-mounted inertial measurement unit (IMU). Optical coherence tomography (OCT) imaging was performed at baseline and during natural interruptions of posturing for meals and toilet visits to measure RD progression toward the fovea.

Results

The Spearman correlation coefficient with RD progression was 0.37 (P = 0.001, r_s² = 0.13) for compliance, 0.52 (P < 0.001, r_s² = 0.27) for rotational acceleration, and 0.49 (P < 0.001, r_s² = 0.24) for linear acceleration. The correlation coefficient between RD progression and rotational acceleration was statistically significantly higher than the correlation coefficient between RD progression and compliance (P = 0.034).

Conclusion

The strength of the correlation between RD progression and compliance was moderate. However, the correlation between RD progression and rotational and linear acceleration was much stronger. Preoperative posturing is effective by reducing head movements rather than enforcing head positioning.

Translational Relevance

Monitoring the efficacy of preoperative posturing in macula-on RD using OCT and IMU measurements shows that a new and combined application of these technologies leads to clinically relevant insights.

Retinal detachment in albinism

Purpose

To report the visual and anatomic outcomes of albino retinal detachment (ARD) repair.

Methods

Collaborative retrospective analysis of ARD. Outcome measures were number of surgical interventions, final retinal reattachment, and best corrected visual acuity (BCVA) at last follow-up.

Results

Seventeen eyes of 16 patients (12 males; mean age =37.8 years) had the following complications at presentation: macula off (14), total (7) or inferior detachment (5), proliferative vitreoretinopathy (5), detectable break (16), lattice (5), horseshoe tears (9), and giant tear or dialysis (4). Mean number of interventions was 1.8 (range =1–5) and included cryopexy (15) with scleral buckle (11), and/or vitrectomy (8). Mean initial BCVA was counting finger (CF) 1 m and at last follow-up (mean 77 months) CF4m with mean improvement of 4.5 lines (early treatment diabetic retinopathy study) (P=0.05). Intraoperative choroidal hemorrhage occurred in three eyes. The retina was finally attached in 14 eyes, with residual inferior detachment in three eyes with silicone oil in situ. Silicone oil was kept in six of seven eyes because of residual inferior detachment (3) and removal of silicone oil, which led to redetachment (1) or fear of redetachment (2).

Conclusion

Repair of ARD may require several interventions, with the need to keep silicone oil in several cases due to nystagmus and reduced melanin pigment.

Missed retinal breaks in rhegmatogenous retinal detachment

AIM

To evaluate the causes and associations of missed retinal breaks (MRBs) and posterior vitreous detachment (PVD) in patients with rhegmatogenous retinal detachment (RRD).

METHODS

Case sheets of patients undergoing vitreo retinal surgery for RRD at a tertiary eye care centre were evaluated retrospectively. Out of the 378 records screened, 253 were included for analysis of MRBs and 191 patients were included for analysis of PVD, depending on the inclusion criteria. Features of RRD and retinal breaks noted on examination were compared to the status of MRBs and PVD detected during surgery for possible associations.

RESULTS

Overall, 27% patients had MRBs. Retinal holes were commonly missed in patients with lattice degeneration while missed retinal tears were associated with presence of complete PVD. Patients operated for cataract surgery were significantly associated with MRBs (P=0.033) with the odds of missing a retinal break being 1.91 as compared to patients with natural lens. Advanced proliferative vitreo retinopathy (PVR) and retinal bullae were the most common reasons for missing a retinal break during examination. PVD was present in 52% of the cases and was wrongly assessed in 16%. Retinal bullae, pseudophakia/aphakia, myopia, and horse shoe retinal tears were strongly associated with presence of PVD. Traumatic RRDs were rarely associated with PVD.

CONCLUSION

Pseudophakic patients, and patients with retinal bullae or advanced PVR should be carefully screened for MRBs. Though Weiss ring is a good indicator of PVD, it may still be over diagnosed in some cases. PVD is associated with retinal bullae and pseudophakia, and inversely with traumatic RRD.

Macula-Sparing Rhegmatogenous Retinal Detachment: Is Emergent Surgery Necessary?

The status of the macula is a significant factor in determining final visual outcomes in rhegmatogenous retinal detachment (RRD) and should be considered in the timing of surgical repair. Several studies have shown that macula-involving RRDs attain similar visual and anatomic outcomes when surgery is performed within seven days as compared to emergent surgery (within 24 hours). In contrast, surgery prior to macular detachment in macula-sparing RRDs generally yields the best visual outcomes. In the case of macula-sparing RRDs, it is not clear how long the macula may remain attached, therefore, standard practice dictates emergent surgery. Timing of presentation, examination findings, case complexity, co-existing medical conditions, surgeon expertise, and timing and quality of access to operating facilities and staff, however, should all be considered in determining whether a macula-sparing RRD requires immediate intervention or if equivalent visual and possibly better overall outcomes can be achieved with scheduled surgery within an appropriate time frame.

Using patient positioning to promote resorption of subretinal fluid in rhegmatogenous retinal detachment before pneumatic retinopexy

PURPOSE

The purpose of this study was to determine if the volume of subretinal fluid in patients with acute rhegmatogenous retinal detachment may be reduced through patient positioning before pneumatic retinopexy.

METHODS

This was a prospective, masked nonrandomized cohort study examining the change in subretinal fluid volume in patients with rhegmatogenous retinal detachment before and after a 1-hour period of specific head positioning, as measured using B-scan ultrasonography. A series of B-scans, each 2 mm apart in the sagittal plane, were acquired for each eye both before and after the positioning period with the patient lying in a supine position.

RESULTS

Ten patients with acute unilateral rhegmatogenous retinal detachment were enrolled. All patients experienced a reduction in subretinal fluid volume, from a mean prepositioning volume of 0.89 ± 0.63 mL to a mean postpositioning volume of 0.45 ± 0.43 mL. The mean relative reduction in subretinal fluid measured as a percentage of prepositioning subretinal fluid volume was 55.4% ± 20%, ranging from 35.3% to 93.5%.

CONCLUSION

In patients with acute rhegmatogenous retinal detachment that fall within the classic indications for pneumatic retinopexy, significant reduction of subretinal fluid volume may be obtained through a 1-hour period of patient positioning in a retinal break-dependent manner.