Persistence of Inflammation After Uncomplicated Cataract Surgery: A 6-Month Laser Flare Photometry Analysis

Thermoelectric Measuring Equipment for Perioperative Monitoring of Temperature and Heat Flux Density of the Human Eye in Vitreoretinal Surgery

Perioperative monitoring of the ocular heat transfer is important for increasing the safety of long-term vitreoretinal surgery. The study is aimed at studying new thermoelectric measuring devices for comprehensive perioperative monitoring of ocular temperature and heat fluxes in vitreoretinal surgery. This pilot, open-label, prospective study included 23 patients (23 eyes) with proliferative diabetic retinopathy (PDR) in both eyes. The thermoelectric devices were developed for measuring intraocular temperature in vitreoretinal surgery and for determining the ocular surface temperature (OST) and heat flux (HF) density. In all cases, OST and HF density of both eyes were recorded (before and after surgery). Intraocular temperature and temperature of the irrigation fluid were measured intraoperatively. No complications associated with the perioperative use of thermoelectric temperature and HF sensors were identified during the study. The successful application of thermoelectric temperature and HF sensors, developed specifically for ophthalmological applications, in comprehensive perioperative monitoring of ocular heat transfer in patients with PDR in vitreoretinal surgery was demonstrated for the first time. Further research is needed to confirm the benefits of perioperative temperature monitoring in vitreoretinal surgery, as well as to develop equipment for active management of temperature in surgical practice.

Hydrophobic and Hydrophilic IOLs in Patients with Uveitis - A Randomised Clinical Trial

Purpose

To compare inflammatory response, visual acuity, and complications of two intraocular lenses (IOLs) in patients with and without uveitis.

Setting

Tertiary referral centre at Sahlgrenska University Hospital/Mölndal, Sweden.

Design

Prospective randomised controlled trial.

Patients and Methods

Patients with and without uveitis eligible for cataract surgery were randomised to receive a hydrophobic or a hydrophilic square-edged intraocular lens (IOL). Patients undergoing bilateral surgery received a hydrophobic IOL in one eye and a hydrophilic in the other. Visual acuity, flare, and central foveal thickness were used as outcome measures.

Results

In total, 34 (61%) patients (52 eyes) with uveitis and 22 (39%) non-uveitic patients (38 eyes) were included in the study. Comparable corrected distance visual acuity (CDVA) was seen, regardless of IOL material. Flare, six months postoperatively, for those undergoing bilateral surgery, showed no significant difference between eyes receiving a hydrophilic IOL or a hydrophobic IOL; mean difference was -3.2 (SD ± 20.7) ph/ms between eyes with uveitis (p = 0.53) and -0.6 SD ± 7.5 ph/ms between eyes without uveitis (p = 0.77). No significant difference in cystoid macular edema (CME) was seen for uveitic patients receiving a hydrophobic IOL (n = 2; 8.0%) and those receiving a hydrophilic IOL (n = 6; 22.2%; p = 0.25).

Conclusion

No significant differences in postoperative inflammatory reaction or rate of CME were seen regardless of using a hydrophobic or a hydrophilic IOL. In general, an improvement in CDVA was seen after cataract surgery with both types of IOLs. Thus, the present study did not support either of the IOL materials as advantageous in patients with uveitis.

Subconjunctival injection of microcrystalline prodrug of dexamethasone for long-acting anti-inflammation after phacoemulsification surgery

Long-acting injectable formulations of dexamethasone with minimal invasiveness are highly desired to manage chronic ocular inflammatory conditions. Here, we applied microcrystals (MCs) of a hydrophobic acetone-based ketal-linked prodrug of dexamethasone (SKD) to treat postoperative ocular inflammation. We compared the efficacy and safety of SKD MCs through subconjunctival (SC) injection with that of Maxidex (a topical suspension of dexamethasone MCs) through SC injection and eye drops in the phacoemulsification combined with intraocular lens implantation (Phaco-IOL) rabbit model. In Phaco-IOL rabbit eyes, a single SC injection of SKD MCs (0.4 mg dexamethasone equiv.) showed anti-inflammatory effects comparable to Maxidex eye drops and completely alleviated the inflammation within 28 days, while an SC injection of Maxidex at the same dose only provided anti-inflammatory effects for 7 days. The study on the dose-dependent anti-inflammatory effects of SKD MCs showed no significant difference in anti-inflammatory effects for the high dosage (0.8 mg dexamethasone equiv.) and the low dosage (0.4 mg dexamethasone equiv.) in 28 days. Nevertheless, systematic drug distribution of SKD MCs and Maxidex in normal rabbits after SC injection demonstrates that the drug concentration in conjunctiva was higher for the high dosage and that a considerable amount of prodrug and dexamethasone could still be detected in the cornea and iris-ciliary body at least 84 days for SKD MCs at high dosage. Furthermore, no persistent elevated intraocular pressure and abnormality in retinal structure and thickness were observed, confirming the excellent safety of long-acting SKD MCs post-SC injection. Our findings provide valuable insights into using prodrug-based MCs for treating ocular postoperative inflammation, and the detailed drug distribution analysis would promote the clinical translation of these MCs in ocular diseases.

Application of smartphone-based infrared thermography devices for ocular surface thermal imaging

Infrared thermography (IRT) is a well-known imaging technique that provides a non-invasive displaying of the ocular surface temperature distribution. Currently, compact smartphone-based IRT devices, as well as special software for processing thermal images, have become available. The study aimed to determine the possible use of smartphone-based IRT devices for real-time ocular surface thermal imaging. This study involved 32 healthy individuals (64 eyes); 10 patients (10 eyes) with proliferative diabetic retinopathy (PDR) and absolute glaucoma; 10 patients (10 eyes) with PDR, who underwent vitreoretinal surgery. In all cases, simultaneous ocular surface IRT of both eyes was performed. In healthy individuals, the ocular surface temperature (OST) averaged 34.6 ± 0.8 °C and did not differ substantially between the paired eyes, in different age groups, and after pupil dilation. In our study, high intraocular pressure was accompanied by a decrease in OST in all cases. After vitreoretinal surgery in cases with confirmed subclinical inflammation, the OST was higher than the baseline and differed from that of the paired eye by more than 1.0 °C. These results highlight that smartphone-based IRT imaging could be useful for the non-invasive detection of OST asymmetry between paired eyes due to increased intraocular pressure or subclinical inflammation.

Implications of Ocular Confounding Factors for Aqueous Humor Proteomic and Metabolomic Analyses in Retinal Diseases

Purpose

To assess the impact of ocular confounding factors on aqueous humor (AH) proteomic and metabolomic analyses for retinal disease characterization.

Methods

This study recruited 138 subjects (eyes): 102 with neovascular age-related macular degeneration (nAMD), 18 with diabetic macular edema (DME), and 18 with cataract (control group). AH samples underwent analysis using Olink Target 96 proteomics and Metabolon's metabolomics platform Data analysis included correlation, differential abundance, and gene-set analysis.

Results

In total, 756 proteins and 408 metabolites were quantified in AH. Total AH protein concentration was notably higher in nAMD (3.2-fold) and DME (4.1-fold) compared to controls. Pseudophakic eyes showed higher total AH protein concentrations than phakic eyes (e.g., 1.6-fold in nAMD) and a specific protein signature indicative of matrix remodeling. Unexpectedly, pupil-dilating drugs containing phenylephrine/tropicamide increased several AH proteins, notably interleukin-6 (5.4-fold in nAMD). Correcting for these factors revealed functionally relevant protein correlation clusters and disease-relevant, differentially abundant proteins across the groups. Metabolomics analysis, for which the relevance of confounder adjustment was less apparent, suggested insufficiently controlled diabetes and chronic hyperglycemia in the DME group.

Conclusions

AH protein concentration, pseudophakia, and pupil dilation with phenylephrine/tropicamide are important confounding factors for AH protein analyses. When these factors are considered, AH analyses can more clearly reveal disease-relevant factors.

Translational Relevance

Considering AH protein concentration, lens status, and phenylephrine/tropicamide administration as confounders is crucial for accurate interpretation of AH protein data.

Anterior chamber flare and choroidal vascular index as inflammatory markers after uncomplicated phacoemulsification surgery

PURPOSE

To determine the effect of phacoemulsification surgery, which is one of the types of cataract surgery by using ultrasonic power to break up the crystalline lens and clean it with vacuum, on anterior chamber flare (ACF) and choroidal vascular index (CVI).

METHODS

For this cross-sectional study, patients were included if they had cataract with nucleus hardness grade 2 or 3, no systemic inflammatory disease, and not use of anti-inflammatory drugs/prostaglandins preoperatively. ACF using a laser flare meter and CVI in patients underwent uncomplicated phacoemulsification was recorded preoperatively, on the postoperative 1st day, 1st week, and 1st month.

RESULTS

Fifty-six eyes were included. ACF was 9.00 ± 2.90 ph/ms preoperatively. Although ACF increased significantly on postoperative day-1 (39.38 ± 23.31ph/ms) and decreased gradually until the 1st month (14.03 ± 6.03ph/ms) after the operation, it was still significantly higher at the 1st month (p < 0.001). Macular and peripapillary CVI increased significantly on postoperative day-1 (0.64 ± 0.03/0.63 ± 0.05) and week-1 (0.64 ± 0.04/0.62 ± 0.04) (p = 0.01, p < 0.001); the postoperative 1st month was similar to the preoperative one (0.59 ± 0.06/0.58 ± 0.06). The relationship between the change in ACF and the change in CVI was not significant.

CONCLUSION

Phacoemulsification causes raises in ACF and CVI due to increased intraocular inflammation. The fact that ACF was significantly higher in postoperative month-1 and CVI returned to its preoperative value suggests that the effect of uncomplicated phacoemulsification surgery on the increase in inflammation in the anterior segment lasts longer than in the posterior segment. These results suggest that ACF and CVI follow-up may be clinically important in the follow-up of postoperative inflammation.

Laser Flare Photometry to Monitor Childhood Chronic Uveitis: A Preliminary Report of a Monocentric Italian Experience

Background: Childhood chronic non-infectious uveitis (cNIU) is a challenging disease that needs close monitoring. Slit lamp evaluation (SLE) is the cornerstone of ophthalmological evaluation for uveitis, but it is affected by interobserver variability and may be problematic in children. Laser flare photometry (LFP), a novel and objective technique, might be used in children with uveitis. Aim: The aim of this study was to attempt the use of LFP in cNIU clinical practice. Methods: Children, attending the Rheumatology Unit and who were scheduled to receive ophthalmological evaluation, were prospectively enrolled to concomitantly receive SLE and LFP. SLE was performed blind to LFP measure. Demographic, laboratory, clinical, and ophthalmology data were collected. Results: A total of 29 children (58 eyes) were enrolled, including 3 with juvenile idiopathic arthritis without uveitis (JIA-no-U), 15 with JIA-associated uveitis (JIA-U), and 11 with idiopathic chronic uveitis (ICU). We observed significantly higher LFP values in the eyes of children with uveitis compared to the others (10.1 IQR 7.1-13.6 versus 6.2 IQR 5.8-6.9, p = 0.007). Accordance between the SLE and LFP measures, at baseline (ρ.498, p < 0.001) and during the follow-up (LFP II ρ 0.460, p < 0.001, LFP III ρ 0.631, p < 0.001, LFP IV ρ 0.547, p = 0.006, LFP V ρ 0.767, p = 0.001), was detected. We evaluated significant correlation between LFP values and the presence of complications (ρ 0.538, p < 0.001), especially with cataract formation (ρ 0.542, p < 0.001). Conclusions: In this cohort, LFP measurements showed a good correlation with SLE. LFP values showed a positive correlation with the presence of complications. LFP might be considered as a reliable objective modality to monitor intraocular inflammation in cNIU.

Changes in Macular Thickness after Cataract Surgery in Patients with Open Angle Glaucoma

BACKGROUND

The purpose of this study was to examine the changes in IOP, total macular and RNFL, ganglion cell layer (GCL) thickness, and aqueous humour flare in open angle glaucoma (OAG) patients before and 6 months after cataract surgery.

METHODS

This was a prospective observational case-control age- and gender-matched study. Groups: 40 subjects in a controlled OAG (OAG_c) group, 20 subjects in an uncontrolled OAG (OAG_u) group, and 60 control group subjects.

EXAMINATION

complete ophthalmic evaluation, IOP measurement, anterior and posterior segment Optical Coherence Tomography (OCT), and laser flare photometry before and 6 months postoperatively.

RESULTS

Six months postoperatively IOP decreased in all groups. An increase in macular thickness was found postoperatively in all groups. Preoperative aqueous humour flare was higher in the OAG_c group than in the control group. After cataract surgery, aqueous humour flare was higher in the control group compared to the preoperative result.

CONCLUSIONS

Changes in IOP following cataract surgery were strongly negatively correlated with preoperative IOP. An increase in macular thickness was observed 6 months postoperatively in all groups. Aqueous humour flare did not differ in OAG_c and OAG_u groups pre- and postoperatively but significantly increased in the control group postoperatively.

Factors influencing aqueous flare after cataract surgery and its evaluation with laser flare photometry

Despite the refinement of modern cataract surgery, postoperative inflammation still constitutes a substantial amount of visual morbidity worldwide. A surrogate for intraocular inflammation and blood-aqueous barrier breakdown can be objectively quantified by Laser flare photometry (LFP). This review outlines the utility of LFP in assessing the assessment of post-cataract surgery inflammation. It highlights the impact of preoperative pathological states such as uveitis and diabetes, intraoperative techniques, including efficient phacoemulsification and direct comparisons between postoperative anti-inflammatory regimes. There is a large interobserver variation in the subjective flare measurement after cataract surgery and the continued use of LFP amongst other objective, noninvasive measurements of intraocular inflammation, particularly in the further development of cataract surgery, is recommended.

Management of inflammation after the cataract surgery

PURPOSE OF REVIEW

To review most recent studies and clinical trials regarding pathogenesis, treatment, and prevention of inflammation after the cataract surgery.

RECENT FINDINGS

FLACS gave opportunity to evaluate inflammatory cytokines in the aqueous humour right after the laser procedure, which led to acknowledging the inflammation pathogenesis during the phacoemulsification. Although there is still a lack of evidence, which would prove the long-term benefit of NSAIDs, they are indicated and effective when risk factors for PCME are present. PREMED studies showed that combination of NSAID and steroids after the surgery for healthy subjects is cost-effective. The triamcinolone injection together with topical steroids and NSAIDs for diabetic patients after the cataract surgery was the most cost-effective in preventing PCME according to the PREMED. Dropless cataract surgery is another emerging topic: dexamethasone implants and suspensions look promising as we await more clinical trials with drug-loaded IOLs.

SUMMARY

Inflammation after the cataract surgery can be prevented, and these methods are one of the most essential topics with growing phacoemulsification rate. Topical NSAIDs are cost-effective not only for patients with risk factors for PCME but also for healthy subjects. New dropless techniques are being successfully introduced in the clinical practice.

Macular vascular density and visual function after phacoemulsification in cataract patients with non-pathological high myopia: a prospective observational cohort study

PURPOSES

This study aimed to evaluate changes in macular vascular density and macular function in patients with high myopia cataract (HMC) after phacoemulsification surgery, using optical coherence tomography angiography (OCTA) and multifocal electroretinography (mfERG).

METHODS

Patients with cataracts scheduled for phacoemulsification surgery were divided into a high myopia group (axial length > 26.5 mm) and a control group (22 mm < axial length ≤ 24.5 mm). OCTA examinations were performed before surgery and at 1 day, 1 week, 1 month, and 3-6 months post-surgery, while mfERG was conducted before surgery and at 3-6 months post-surgery.

RESULTS

A total of 38 patients were included, of whom 20 were HMC patients and 18 were control patients. The macular vascular density significantly increased after phacoemulsification surgery in both groups, while foveal avascular zone area decreased significantly (HMC group: all p < 0.01; control group: all p < 0.05). Mean changes in macular vascular density were significantly greater in HMC patients than in the control group at 1 day after surgery (all p < 0.05). The amplitude density and latency of P1 wave in all macular rings (Ring_1-5) did not differ significantly before or after surgery in either group (all p > 0.1).

CONCLUSION

Phacoemulsification may not affect HMC patients' macular mfERG responses within 3-6 months post-surgery, but it may influence macular microcirculation. HMC patients should be closely monitored after surgery, as their retinal vascular density may fluctuate substantially in the early postoperative period.

Increased risk of postsurgical macular edema in high stage idiopathic epiretinal membranes

PURPOSE

To assess the rate of occurrence and the risk factors of postsurgical macular edema (PSME) in eyes with idiopathic epiretinal membrane (iERM) or full-thickness macular hole (FTMH).

METHODS

Retrospective longitudinal analysis of all subjects scheduled for vitrectomy with or without combined cataract surgery over a 6-month period. Electronic medical charts and imaging data were analyzed preoperatively and at 1, 3 and 6 months after surgery.

RESULTS

From 101 patients diagnosed with iERM or FTMH, 71 patients were eligible for the study. Forty-nine eyes with iERM (69.0%) and 22 eyes with FTMH (31.0%) underwent vitrectomy either isolated (31.0%) or combined with cataract extraction (69.0%). The overall rate of PSME was 26.7%, without differences between the two groups (P = 0.9479). Combined cataract extraction did not affect the overall occurrence of PSME rate in both groups (P = 0.9255 in FTMH and P = 0.8658 in iERM). If grouped by stage, eyes with stage 4 iERM though disclosed an increased rate of PSME (57.1%) compared to lower (1 to 3) stages (14.3%, P = 0.0021), particularly when combined with cataract surgery (71.4% vs. 15.4% in stages ≤ 3, P = 0.0021). The PSME odds ratio for a stage 4 iERM is 8 (95% CI: 1.933-33.1; P = 0.0041) compared to stages 3 and below.

CONCLUSIONS

PSME remains a clinically relevant and frequent event after surgery for iERM and FTMH. Patients with stage 4 iERM have an 8-fold higher likelihood of developing PSME in a 6-month postsurgical period compared to iERM in 1-3 stages, especially when combined with cataract extraction.

Laser flare and cell photometry to measure inflammation after cataract surgery: a tool to predict the risk of cystoid macular edema

PURPOSE

To review the current adoption of laser flare and cell photometry (LFCP) in the setting of modern cataract surgery to analyze inflammation aiming to identify evidence of a correlation between LFCP values and the risk of cystoid macular edema (CME) development.

METHODS

An extensive PubMed literature search was performed to review all the published studies investigating inflammation by LFCP after uncomplicated phacoemulsification. The following keywords were used: cataract surgery, cystoid macular edema, anterior chamber inflammation, laser flare, and cell photometry.

RESULTS

Seventy-eight original articles investigating inflammation by LFCP were selected. Macula alterations were searched in 12 (15%) trials, by optical coherence tomography or fluorescein angiography in 11 (14%) and 1 (1%) studies, respectively. Among them, 9 (12%) papers investigated the correlation between LFCP values and cystic changes to the macula: 7 (9%) and 2 (3%) studies identified a positive and negative correlation, respectively. Three (4%) papers did not perform any correlation analysis.

CONCLUSION

CME, as a consequence of uncontrolled postoperative inflammation, is a common cause for unfavorable visual outcomes following uncomplicated phacoemulsification with IOL implantation. After surgery, intraocular inflammation is generally assessed by qualitative methods. Although well-established and practical in uveitis, they are inadequate to detect the modest inflammatory response that usually occurs after uneventful phacoemulsification. LFCP correlate with the chance of macula alteration after surgery and higher the values higher the risk of CME. The quantitative analysis of intraocular inflammation by LFCP after cataract surgery might be a tool to predict the risk of pseudophakic CME.