Short-Term Changes in Retinal Vasculature and Layer Thickness after Phacoemulsification Surgery

Effect of silicone oil versus gas tamponade on macular layer microstructure after pars plana vitrectomy for macula on rhegmatogenous retinal detachment

PURPOSE

To analyze structural changes in the macular retinal layers and sub-foveal choroidal thickness (SFCT) in eyes after macula-on rhegmatogenous retinal detachment (RRD) repair by pars plana vitrectomy with either silicone oil (SO) or gas tamponade, and the effect of these changes on visual acuity.

PATIENTS AND METHODS

Retrospective study which included 26 eyes in the SO Group and 32 in the Gas Group. Optical coherence tomography (OCT) scans of the affected eyes were obtained before surgery, and 3 months after PPV in the Gas Group, and during silicone oil in situ and 3 months after SO removal, in the SO Group. Qualitative assessment of photoreceptor layer and foveal contour, along with quantitative assessment of macular retinal thickness and SFCT was performed. Postoperative OCT macular microstructural changes were recorded and correlated to corrected distance visual acuity (CDVA). Intraocular pressure (IOP) was measured preoperative and at 3 months post operative.

RESULTS

There was a 2-line loss (from 20/28 preoperatively to 20/40 at final follow-up) of CDVA in the SO Group (p=0.051), while there was no statistically significant change in CDVA in the Gas Group (p=0.786). There was no significant correlation between CDVA loss and duration of silicon tamponade (r=-0.031, p=0.893). There was a statistically significant increase in IOP from its baseline to final follow-up of 0.7 mmHg in the SO Group (p=0.023) while there was no statistically significant change in IOP in the Gas Group. During silicone oil tamponade, there was approximately 11% and 5% of retinal and sub-foveal choroidal thinning respectively, which was moderately resolved following silicone oil removal. 20% (5/24) of eyes in the SO Group had qualitative flattening of foveal contour during SO tamponade that resolved after SO removal.

CONCLUSION

Thinning of the macula was noticed after macula-on RRD repair with SO tamponade. Such thinning was only partially reversible after the removal of SO.

Impact of Phacoemulsification Parameters on Central Retinal Thickness Change Following Cataract Surgery

Cataract surgery can lead to inflammatory processes in the retina due to its invasive nature, resulting in prolonged recovery times and reduced functional outcomes. The aim of the current study is to explore the impact that phacoemulsification parameters have on macular thickness following surgery. This prospective single-center study enrolled 46 healthy patients (46 eyes) who underwent uneventful cataract surgery. Retinal thickness was assessed using optical coherence tomography (OCT) preoperatively, as well as 1, 4, and 12 weeks after surgery. The macula was divided into a central (CMT), inner (IMT), and outer ring (OMT). Cataract density was automatically determined using an anterior segment OCT and a custom MATLAB script. Corrected distance visual acuity (CDVA), intraocular pressure (IOP) as well as cumulative dissipated energy (CDE), ultrasound time (UT), and fluids used during phacoemulsification were recorded. Retinal thickness and volume increased significantly following cataract surgery, reaching its maximum 4 weeks post-operatively. Statistically significant correlations were found between the CDE and IMT, OMT and retinal volume change (rIMT = 0.356, rOMT = 0.298, rvolume = 0.357 with p < 0.05) as well as between the ultrasound time and IMT, OMT, and retinal volume change (rIMT = 0.369, rOMT = 0.293 and rvolume = 0.409 with p < 0.05). Changes in CMT did not correlate with any surgical metrics. Additionally, no correlation was found to the amount of fluid used, whether CDVA or IOP. However, a link between nuclear cataract density and changes in OMT (r = 0.310, p < 0.05) was established. How ultrasound energy impacts the choroidea, and to what extent retinal metabolism changes after surgery, needs to be explored in future studies.

Effect of Conventional Cataract Surgery and Femtosecond Laser-Assisted Cataract Surgery on Bruch's Membrane Opening-Minimum Rim Width, Retinal Nerve Fiber Layer, and Macular Thickness

Purpose

To evaluate the effect of conventional cataract surgery (CCS) and femtosecond laser-assisted cataract surgery (FLACS) on Bruch's membrane opening-minimum rim width (BMO-MRW), peripapillary retinal nerve fiber layer thickness (RNFL), and macular thickness (MT) using spectral-domain optical coherence tomography (SD-OCT).

Methods

BMO-MRW, RNFL, and MT were measured using SD-OCT preoperatively, 1 month and 6 months after surgery in both CCS and FLACS groups. Differences between preoperative and postoperative values were evaluated in both groups. The postoperative changes were evaluated in each group and compared between groups.

Results

A total of 146 eyes of 146 patients were included in this study, 65 underwent CCS, and 81 underwent FLACS. One month after surgery, there was an increase (in microns) of 20.93 in BMO-MRW, 4.26 in RNFL, and 7.85 in MT in CCS group (P < 0.001), and 17.7, 3.73, and 5.65, respectively, in FLACS group (P < 0.001). Six months after surgery, there was an increase of 12.53 in BMO-MRW, 1.42 in RNFL, and 4.72 in MT in CCS group (P < 0.001), and 13.7, 1.88, and 4.14, respectively, in FLACS group (P < 0.001). The postoperative changes in CCS group were similar to those in FLACS group.

Conclusion

CCS as well as FLACS result in a slight increase in BMO-MRW, RNFL, and MT values one month and six months after surgery. Neither CCS nor FLACS lead to a deterioration in the parameters that define the structure of the optic nerve head and the macula. These results suggest that FLACS is as safe as CCS regarding the optic nerve head and the macula in normal eyes.

Application of the Active-Fluidics System in Phacoemulsification: A Review

The fluidics system is an indispensable and primary component of phacoemulsification. Both the gravity-fluidics system and active-fluidics system are commonly used in practice. The irrigation pressure of the gravity-fluidics system is determined by the bottle height, which is relatively constant, while the active-fluidics system is paired with a cassette that contains pressure sensors to monitor intraocular pressure changes. The active-fluidics system allows surgeons to preset a target intraocular pressure value, and it replenishes the fluids proactively; thus, the intraocular pressure is consistently maintained near the target value. Under such circumstances, stable intraocular pressure and anterior chamber volume values could be acquired. Research on surgical safety, efficiency and results have reported several strengths of the active-fluidics system. It is also advantageous in some complicated cataract surgeries. However, the system is not widely used at present, mainly due to its low penetration rate and high equipment cost. Some of its updates such as the new Active Sentry handpiece showed potential superiority in laboratory studies recently, but there is still further research to be conducted. This article gives an overview of the mechanism and performance of the active-fluidics system, and it is expected to provide clues for future research.

A prospective randomized clinical trial of active-fluidics versus gravity-fluidics system in phacoemulsification for age-related cataract (AGSPC)

BACKGROUND

To figure out the efficacy, effects, safety and patient's subjective perceptions of phacoemulsification with the active-fluidics system (AFS).

PATIENTS AND METHODS

This was a prospective, randomized, double-masked, controlled clinical study. Age-related cataract patients were recruited and randomly assigned to the AFS group and gravity-fluidics system (GFS) group in a ratio of 1:1 to have phacoemulsification. Participants were followed up at one day, one week, one month and three months postoperatively (Chinese Clinical Trial Registry, ChiCTR2100044409).

RESULTS

The overall included participants were 107 finally. The total aspiration time of the AFS group was significantly less than that of the GFS group (p = .020), while no significant difference existed in cumulative dissipated energy and estimated fluid usage between the two groups. The best corrected visual acuity was significantly better in the AFS group at one day and one week postoperatively (p = .002, p = .038 respectively). The recovery of central corneal thickening and macular superficial vasculature increase was earlier in the AFS group. The central retinal thickness was significantly higher in the GFS group at one month and three months postoperatively (p = .029, p = .016 respectively). The incidence of corneal adverse events was higher in GFS group (p = .035). No serious adverse events occurred in either group. Pain scores and the scores of Cat-PROM5 questionnaire of the AFS group were significantly lower than that of the GFS group (p = .011, p = .002 respectively).

CONCLUSION

AFS improves the efficiency, effects, safety and patients' subjective perceptions of phacoemulsification compared with GFS. It is worthwhile to promote its application in cataract surgery.KEY MESSAGESThe active-fluidics system automatically detects and maintains stable intraocular pressure at the set value.The active-fluidics system improves the efficiency, effects, safety and patients' subjective perceptions in phacoemulsification.

Decreased Macular Retinal Thickness in Patients With Pterygium

Purpose

To explore alterations in macular retinal thickness (RT) and analyze correlation between macular RT and pterygium area, length in pterygium patients.

Methods

Totally 13 patients with pterygium (left eye) and 13 healthy controls (left eye) were recruited. OCTA was applied to scan each eye to generate three-dimensional images. Based on the Early Treatment Diabetic Retinopathy Study (ETDRS) method, each image was divided into nine subregions for the ETDRS: central (C); inner superior (IS); outer superior (OS); inner nasal (IN); outer nasal (ON); inner inferior (II); outer inferior (OI); inner temporal (IT); and outer temporal (OT). The macular RT in each subregion was measured. Furthermore, the correlation between RT and the area, length of pterygium was analyzed.

Results

The visual acuity of pterygium patient was different from that of the control (P < 0.05). Besides, decreased intraretinal thickness of the IN and ON, increased intraretinal thickness of OT, decreased extraretinal thickness of OT, IN, ON, OS, and decreased retinal full layer thickness of medial superior, OS, IN, ON, and II subregions in pterygium group were observed. There was a negative correlation between RT of the IN and ON subregions and the length of pterygium (r = -0.5803 and r = -0.6013, P = 0.0376 and P = 0.0297). The RT of IN subregion was negatively correlated with pterygium area (r = -0.5844, P = 0.0359). According to the receiver operating characteristic analysis, in the ON subregion, the areas under the curve of the inner retinal thickness, outer retinal thickness and the whole retinal thickness were 1.0 (95% CI: 1.0), 0.882 (95% CI: 0.715 and 0.963), and 1.0 (95% CI: 1.0). The smallest area under the curve of retinal thickness in OT subregion was 0.018 (95% CI: 0-0.059).

Conclusion

RT of pterygium patients was significantly decreased, and the main alterations occurred in the temporal side suggesting there might exist retinal structural alterations in pterygium.

Long-Term Variations in Retinal Parameters after Uncomplicated Cataract Surgery

Background: Cataract phacoemulsification surgery provides excellent refractive results; however, it also elicits changes in the posterior segment of the eye. This study aimed to determine changes in retinal parameters measured by spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA) after an uncomplicated cataract surgery, including the impact of effective phacoemulsification time (EPT). Methods: The study included 44 patients without retinal abnormalities, followed up after unilateral uncomplicated cataract phacoemulsification in a single ophthalmological unit. Patients were evaluated for the following parameters at baseline and at 2 weeks, 3 months, and 12 months after the surgery: best corrected visual acuity, central retinal thickness (CRT), average central retinal thickness (CRTA), central retinal volume (cube volume (CV)), vessel density central (VDC), vessel density full (VDF), vessel perfusion central (VPC), and vessel perfusion full (VPF). The EPT recorded at each procedure was used as a covariant for the evaluation of changes in retinal parameters after the surgery. Analysis included 44 eyes for SD-OCT and 17 for OCTA evaluation, according to adopted scan quality thresholds. Results: A significant increase in CRT, CRTA, and CV was noted at each follow-up point compared with baseline. The rising tendency was observed in the first 3 months after the surgery, with a decline over the subsequent months. The VPF parameter showed a stable improvement after the surgery. The analysis of covariance did not confirm any significant effect of the EPT on variations in CRT, CV, CRTA, VDC, and VPF and there was a weak effect on the VDF parameter. Conclusions: Uncomplicated cataract surgery results in an increase in retinal thickness and volume in the first few months after the surgery, followed by a spontaneous decline in these parameters in the subsequent months. A long-standing improvement is noted in the VPF parameter.

An Assessment of Cataract Severity Based on Antioxidant Status and Ascorbic Acid Levels in Aqueous Humor

Cataract is the leading cause of blindness throughout the world. Currently, the cataract severity evaluation is based on the subjective LOCS III guideline. To ameliorate the evaluation system and develop an objective and quantitative analysis, we investigated the relationships among aqueous humor total antioxidant capacity (AqTAC), ascorbic acid (AqAA) concentration, and cataract severity. In this study, we enrolled 130 cataract patients who underwent phacoemulsification between April 2019 and March 2020. The AqTAC and AqAA were measured by our own developed TAC assay and commercially available kit. Cataract severity was recorded by nuclear opalescence (NO) and cortical cataract (CC) degree according to LOCS III. Cumulative dissipated energy (CDE) during phacoemulsification was recorded to verify the severity of the cataract. As a result, we found a moderate correlation between AqTAC and CDE (p < 0.001). In addition, we found AqTAC independently associated with the CDE when analyzed by multivariate linear regression (p < 0.001). AqTAC also negatively correlated to cataract severity when measured by NO and CC (p = 0.012 in NO grade 3 vs. grade 1; p = 0.012 in CC grade 2 vs. grade 1; p < 0.001 in CC grade 3 vs. grade 1). We further found AqAA provided 71.9 ± 13.5% of AqTAC, and showed a high correlation (rho = 0.79, p < 0.001). In conclusion, we found a significant correlation between AqTAC/AqAA and cataract severity measured by CDE. The correlation was superior to the correlation between LOCS III and CDE. Aqueous humor TAC owns the potential to assess cataracts in an objective and quantitative way.

Decreased retinal microvasculature densities in pterygium

AIM

To investigate the retinal vascular network alterations in eyes of patients with pterygium.

METHODS

Totally 18 left eyes from 18 female pterygium patients and 18 left eyes from 18 female healthy control subjects were enrolled. Optical coherence tomography angiography (OCTA) images were generated of the superficial retinal layer and deeper retinal layer of the macular retina for each eye. The microvascular (MIR) and macrovascular (MAR) densities were calculated and MIR, MAR, and total microvascular (TMI) density was compared in the healthy control and pterygium groups.

RESULTS

In pterygium group, in the superficial retinal layer, the vascular density in superficial MIR, superior right (SR), inferior right (IR), right (R), superficial central annuli (SC)1, SC2, and SC3 decreased significantly in the macular area (P<0.05). Furthermore, the vascular density in all those decreased regions except R, was significantly and negatively correlated with the disease course (r=-0.6038 to -0.7762, P=0.0008), and the area size of pterygium (r=-0.6043 to -0.9508, P<0.05). For the deeper retinal layer, the density of deep total microvessel (DTMI), deeper MIR, SR, IR, R, DC2, and DC3 decreased significantly in macular area of pterygium patients (P<0.05). Furthermore, the vascular density in all those decreased regions was significantly and negatively correlated with the disease course (r=-0.6901 to -0.7795, P=0.0015), and the area size of pterygium (r=-0.6043 to -0.9563, P<0.05). No statistically significant differences and correlation was found in other region density (|r|<0.47, P>0.05).

CONCLUSION

OCTA findings suggest that pterygium patients present with decreased retinal MIR density, and the major vascular alterations occurr mainly on the bitamporal side. The vascular density of the superficial SC1, SC2, SC3 adjacent to the foveal and deep layer of DC2, DC2 regions, significantly decreased.

Influence of one or two horizontal muscle surgeries on OCT findings

We investigate the effects of differences between one or two horizontal rectus muscle surgeries (recession ± resection) on the central macular thickness (CMT), subfoveal choroidal thickness (SFCT), and retinal nerve fiber layer (RNFL). Measurements of the CMT, SFCT, and RNFL in patients who underwent horizontal rectus muscle surgery were obtained using optical coherence tomography (OCT). Patients were grouped as those who had undergone rectus muscle recession surgery (Group 1) and those who had undergone rectus muscle recession + resection surgery (Group 2). The CMT, SFCT, and RNFL in patients were measured preoperatively and 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. A total of 65 eyes of 50 patients were analyzed retrospectively. The average age of the 25 patients in Group 1 was 8.96 ± 7.966 years (min 3, max 38). The average age of the 25 patients in Group 2 was 15.17 ± 6.806 years (min 2, max 34). The comparison of the preoperative and the 1-day and 1-week postoperative values revealed an increase in CMT and SFCT in Group 1 and Group 2. There were no significant differences between the two groups. It was observed that this increase reached the preoperative values after 1-3 months and 6 months in both groups. There was no statistically significant change in the RNFL. Rectus muscle surgery (recession±resection) caused an increase in CMT and SFCT in the early stage, which was possibly caused by the altered choroidal microcirculation resulting from mechanical traction during surgery and by postoperative inflammation. There was no difference between one or two muscle surgeries.

Changes in Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer after Femtosecond Laser-Assisted Cataract Surgery Compared to Manual Phacoemulsification in Patients Receiving a Trifocal Intraocular Lens

Introduction

During femtosecond laser-assisted cataract surgery (FLACS), there is a significant increase in intraocular pressure, which might lead to ganglion cell damage. We aimed to determine whether there were differences in the changes produced in the ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) thickness, as evaluated with optical coherence tomography (OCT), between phacoemulsification and FLACS, after implantation of a trifocal intraocular lens (IOL).

Methods

Patients with no coexistent pathologies undergoing cataract surgery with implantation of a PanOptix IOL were explored with the Cirrus-OCT before and three months after surgery. GCC values were obtained from the built-in software. The differences between pre- and postoperative GCC and pRNFL thicknesses after phacoemulsification were compared to differences after FLACS.

Results

A total of 171 eyes were included, 74 undergoing FLACS and 97 phacoemulsification. For both groups, there was a statistically significant increase in GCC values after cataract surgery, except for the inferior and inferonasal sectors. There were no statistically significant differences between FLACS and phacoemulsification. Mean change in average GCC and minimum GCC were 1.08 ± 1.40 µm (range −1 to +6 µm) and 1.69 ± 2.54 µm (range −3 to +11 µm) after FLACS and 0.99 ± 1.67 µm (range −5 to +6 µm) and 2.02 ± 3.54 µm (−6 to +18 µm) after phacoemulsification. These values are similar to those previously reported after phacoemulsification with monofocal IOL implantation. No significant changes after surgery were detected for the pRNFL, with no differences between groups. Discussion. There were no differences in the changes produced by FLACS and phacoemulsification in either GCC or pRNFL values. Although mean change was small, the range of variation was wide. Therefore, it is necessary to establish a new baseline for GCC and pRNFL thicknesses after cataract surgery in order to monitor any subsequent changes.

Transient reduction in macular deep capillary density on optical coherence tomography angiography after phacoemulsification surgery in diabetic patients

Background

To evaluate macular microvascular changes and associated factors in diabetic patients following uncomplicated phacoemulsification surgery.

Methods

In this prospective observational study, we enrolled diabetic patients and non-diabetic controls who underwent phacoemulsification surgery. Participants were examined at postoperative day 1 (POD1), 10 (POD10), 30 (POD30), and 90 (POD90), using macular 3x3mm OCT angiography scan (RTVue-XR Avanti; Optovue, Inc., Fremont, CA). Integrated automated algorithms were used to quantify parafoveal vessel density (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP). To minimize measurement bias, subjects with corneal edema or capsular opacity at any postoperative visit were excluded.

Results

The study included 21 eyes of 21 diabetic patients and 21 eyes of 21 non-diabetic controls. In diabetic patients, no significant change in SCP-VD could be detected (P = 0.57); DCP-VD reduced from 50.24 ± 2.33% at POD1 to 48.33 ± 3.07% at POD30 (P = 0.019), and restored to 50.74 ± 3.44% at POD90 (P = 1.00). The DCP-VD change at POD30 in diabetic patients (− 1.90 ± 2.61%) was significantly different from that in controls (1.31 ± 2.61%) (P < 0.001). The amount of DCP-VD reduction was correlated with foveal and parafoveal thickening (r = 0.431, P = 0.051 and r = 0.514, P = 0.017, respectively), high cumulative dissipated energy (P = 0.032) and increased hemoglobin A1c concentration (P = 0.037).

Conclusions

Phacoemulsification in diabetic patients caused transient reduction in DCP-VD, which was associated with poor glycemic control, surgical trauma, and postoperative macular thickening. Our results added a new dimension to our understanding of the complex biologic effects of cataract surgery in diabetic subjects.

Comparison of fundus changes following silicone oil and sterilized air tamponade for macular-on retinal detachment patients

BACKGROUND

To investigate different tamponade effects of intravitreal silicone oil (SO) and sterilized air on macular vasculature and structure after successful retinal repair for macular-on rhegmatogenous retinal detachment (RRD) patients.

METHOD

21 eyes (21 patients) with macular-on RRD underwent single pars plana vitrectomy following intravitreal SO or sterilized air (Gas) tamponade. Optical Coherence Tomography (OCT) and angiography were used to evaluate retinal layer thickness and flow density (FD) changes throughout the observation period of 12 weeks. Retinal layers were segmented into 7 sets: NFL, GCL + IPL, INL, OPL, ONL + IS, OS+RPE and BRM. Macular perfusion system was segmented into superficial and deep capillary plexus flow density (SCPFD, DCPFD), and choriocapillaries plexus flow density (CCPFD).

RESULT

Compared to Gas tamponade, SO tamponade led to more decrease in both superficial and deep retinal blood flow during observation. NFL thickness was found to decrease in both Gas tamponade and SO tamponade eyes. SO tamponade resulted in more pronounced decrease which led to significant intergroup difference. Opposite changing trends were found in GCL + IPL and ONL + IS thicknesses due to different means of tamponade. SO tamponade caused thicknesses of these two segmented layers to decrease, which led to significant intergroup differences. SO tamponade also led to more decrease in INL, OPL thicknesses. No significant intergroup difference of choroidal thickness was observed.

CONCLUSION

Compared to gas, silicone oil could have more negative tamponade effects on both fundus vasculature and structure.