Comparison of postoperative ciliary body changes associated with the use of 23-gauge and 20-gauge system for pars plana vitrectomy

Outcomes and predictors of vitrectomy and silicone oil tamponade in retinal detachments complicated by proliferative vitreoretinopathy

AIM

To evaluate outcomes and determine factors influencing the outcomes of vitrectomy with silicone oil (SO) endotamponade for the management of rhegmatogenous retinal detachment (RRD) complicated by advanced proliferative vitreoretinopathy (PVR).

METHODS

This is a retrospective, interventional case series of eyes with PVR grade C associated RRD with or without prior surgery that underwent vitreoretinal surgery and SO tamponade. Eyes with a minimum follow-up of 6mo after SO extraction were included. Eyes were classified into three PVR subgroups according to severity and extension of proliferation. The influence of several preoperative, intraoperative and postoperative factors upon the functional and anatomical outcomes was assessed using multivariate logistic regression analysis.

RESULTS

A hundred and one eyes of 101 patients that met the inclusion criteria were studied. Seventy-five of 101 eyes (74.3%) had successful retinal reattachment after one operation. Increased aqueous cell and flare at the first week exam had a statistically significant association with redetachment, recurrent membrane proliferation and keratopathy. Visual acuity improvement was significantly associated with faint postoperative aqueous inflammation values, primary vitrectomy and PVR outside of the posterior pole.

CONCLUSION

Although encouraging anatomical and functional outcomes are achieved after vitrectomy and SO tamponade in eyes with RRD complicated by PVR, an increase in aqueous flare or cells at the first week follow-up is most likely to result in postoperative late complications. Primary vitrectomy, PVR associated with minimal posterior pole extension and absent to mild postoperative aqueous inflammation are associated with improved post-operative final visual acuity.

Pars Plana Vitrectomy Port Sizes: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The uptake of small-gauge (SG; ie, 23-gauge [23-G], 25-gauge [25-G], and 27-gauge [27-G]) pars plana vitrectomy (PPV) has grown. We aim to investigate the advantages and disadvantages of various PPV port sizes in a meta-analysis of randomized controlled trials (RCTs).

MATERIALS AND METHODS

A systematic literature search was performed for RCTs comparing PPV port sizes for any indication. Weighted mean differences (WMDs) and risk ratios (RRs) were calculated, and meta-analysis was performed with random-effects models.

RESULTS

A total of 1,678 eyes from 22 RCTs were included. Risk-of-bias assessment found some concerns in 13 studies. Compared with 20-gauge PPV, there was no significant difference in the final or change in best-corrected visual acuity (BCVA; five studies analyzed each) relative to that of SG PPV. SG PPV was associated with a significantly greater incidence of hypotony (RR = 3.79; 95% confidence intervals [CI], 2.02 to 7.10; P < .0001; six studies) and choroidal detachment (RR = 5.65; 95% CI, 1.01 to 31.71; P = .05; three studies). Compared with 25-G PPV, there was no significant difference in BCVA at any time point with 23-G (two studies), and significantly more frequent port suturing was required with 23-G (RR = 0.46; 95% CI, 0.25 to 0.84; P = .01; two studies). Compared with 25-G PPV, 27-G was associated with a significantly better final BCVA (WMD = -0.06 logMAR; 95% CI, -0.11 to -0.01; P = .02; five studies) and a significantly lengthened surgery (WMD = 4.11 minutes; 95% CI, 0.18 to 8.05; P = .04; three studies).

CONCLUSIONS

There was no significant difference in visual or surgical outcomes following 20-gauge PPV relative to SG PPV (Grading of Recommendations, Assessment, Development, and Evaluation recommendation: low certainty), and there was an increased risk of postoperative complications with SG PPV (moderate certainty). Compared with 25-G PPV, 23-G required more frequent port suturing (moderate certainty), whereas 27-G may be associated with a better final BCVA but longer surgery (low and moderate certainty, respectively). [Ophthalmic Surg Lasers Imaging Retina. 2022;53:152-158.].

Repeatability and Reliability of Quantified Ultrasound Biomicroscopy Image Analysis of the Ciliary Body at the Pars Plicata

Most of the ciliary body and ciliary processes of the eye cannot be directly visualized in vivo because of the posterior location of the pars plicata to the posterior chamber and iris. However, ciliary anatomy can be effectively imaged using ultrasound biomicroscopy (UBM) by placing the probe close to the limbus, perpendicular to this structure. Previous studies measuring ciliary body parameters in meridian UBM images found that these parameters were measured with poor reliability and repeatability. This study evaluates the intra-observer reliability and inter-observer agreement of a standardized protocol for measuring six ciliary parameters in transverse or quadrant UBM images that capture an entire row of ciliary processes. All six ciliary parameters have high intra-observer reliability, with ciliary body thickness, ciliary process length and ciliary process density measurements being the most consistent for each observer. The coefficient of variation for each observer ranged from 1.4%-15%. Inter-observer agreement was also high for all six parameters, with an intra-class correlation coefficient >0.8. Utilizing transverse UBM images of the pars plicata allows for consistent quantitative analysis in control subjects.

Comparison of postoperative anterior segment changes associated with pars plana vitrectomy with and without vitreous base shaving

AIM

To compare changes in anterior segment topography and axial length (AL) evaluated with Pentacam and IOL Master after pars plana vitrectomy (PPV) performed with and without vitreous base shaving.

METHODS

This prospective study included patients who underwent PPV or phacoemulsification+PPV (Phaco+PPV) for various indications. Patients who underwent total posterior hyaloid detachment and excessive vitreous base shaving with scleral indentation were referred to as complete PPV (c-PPV). The patients whom posterior hyaloid was separated as far as the posterior arcades and vitreous base shaving with scleral depression was not performed were classified as the partial PPV (p-PPV) group. All patients underwent detailed ophthalmologic examinations preoperatively and 1wk, 1, and 3mo postoperatively. Changes in the anterior chamber depth (ACD), anterior chamber volume (ACV), iridocorneal angle (ICA), central corneal thickness (CCT), and keratometric measurements (K₁ and K₂) were evaluated with Pentacam HR. Changes in the AL measurements were analyzed with IOL Master.

RESULTS

A significant increase in ACD was observed in c-PPV cases (P=0.02), but this increase was not significant in the p-PPV group (P=0.053). In contrast, ICA increased significantly in the c-PPV group (P=0.02) but decreased in the p-PPV group (P=0.09). BCVA was significantly improved in the c-PPV group from week 1 (P<0.001) while the increase in the p-PPV group reached significance at 3mo (P=0.035). CCT increased in the first week and later returned to baseline in both groups. No significant differences in the other parameters were observed between the groups, and there were no significant changes in intraocular pressure, ACV, AL, K₁ or K₂ values (P>0.05 for all).

CONCLUSION

Incomplete posterior hyaloid excision and not removing the vitreous base in PPV surgeries may create a more stable anterior chamber, thus preventing the downward movement of the lens-iris diaphragm, and may cause ciliary body retraction, thereby reducing ICA. Awareness of these effects can provide some amount of guidance to physicians in selecting the appropriate PPV procedure and preempting surgical complications.