Foveal thickness after phacoemulsification as measured by optical coherence tomography

Impact of Lens Opacity on Optical Coherence Tomography Angiography Metrics

PURPOSE

To evaluate the impact of lens opacity on the reliability of optical coherence tomography angiography metrics and to find a vessel caliber threshold that is reproducible in cataract patients.

METHODS

A prospective cohort study of 31 patients, examining one eye per patient, by applying 3 × 3 mm macular optical coherence tomography angiography before (18.94 ± 12.22 days) and 3 months (111 ± 23.45 days) after uncomplicated cataract surgery. We extracted superficial (SVC) and deep vascular plexuses (DVC) for further analysis and evaluated changes in image contrast, vessel metrics (perfusion density, flow deficit and vessel-diameter index) and foveal avascular area (FAZ).

RESULTS

After surgery, the blood flow signal in smaller capillaries was enhanced as image contrast improved. Signal strength correlated to average lens density defined by objective measurement in Scheimpflug images (Pearson's r: -.40, p: .027) and to flow deficit (r= -.70, p < .001). Perfusion density correlated to the signal strength index (r = .70, p < .001). Vessel metrics and FAZ area, except for FAZ area in DVC, were significantly different after cataract surgery, but the mean change was approximately 3-6%. A stepwise approach in extracting vessels according to their pixel caliber showed a threshold of > 6 pixels caliber (∼20-30 µm) was comparable before and after lens removal.

CONCLUSION

In patients with cataract, OCTA vessel metrics should be interpreted with caution. In addition to signal strength, contrast and pixel properties can serve as supplementary quality metrics to improve the interpretation of OCTA metrics. Vessels with ∼20-30 µm in caliber seem to be reproducible.

Evaluation of structural and vascular changes in the choroid after uneventful phacoemulsification surgery

Objective: The aim of this study was to evaluate structural and vascular changes in the choroid after phacoemulsification surgery. Methods: This research comprised 50 eyes of 50 individuals who received uneventful surgical treatment for cataracts. Intraocular pressure, axial length, subfoveal choroidal thickness, and choroidal thickness in the nasal and temporal areas at 1,500-micron distance from the fovea were measured before surgery and at one and three months after surgery. At the same evaluation times, the choroidal luminal area and choroidal stromal area were calculated with the binarization method using image J software, and the choroidal vascular index (CVI) was calculated by dividing the luminal area by the total area. In addition, total surgery time and effective phacoemulsification time were recorded. Results: The patients had a mean age of 64.7 ± 8.5 years. The mean total operative time was 13.9 ± 3.8 minutes, and the mean effective phacoemulsification time was 3.8 ± 2.1 minutes. The mean intraocular pressure value was 14.4 ± 3.4 mmHg before surgery, and 13.2 ± 2.9 mmHg at the first month and 13.0 ± 2.1 mmHg at the third month postoperatively. Although there was a decrease in the intraocular pressure after surgery, no significant difference was found (p>0.05 for all). The axial length measured during the first and third months postoperatively did not significantly differ from the evaluation undertaken preoperatively (p>0.05 for all). A significant increase was detected in the subfoveal, nasal, and temporal choroidal thicknesses at the first postoperative month compared to the preoperative values (p<0.05), but no significant difference was found at the third month postoperatively (p>0.05). The mean CVI was 61.6 ± 3.5% preoperatively, 65.2 ± 4.2% at the first postoperative month, and 65.9 ± 3.9% at the third postoperative month. The increase at the first and third postoperative months was significant when compared to the evaluation made preoperatively (p=0.004 and p<0.001, respectively). Conclusion: Structural and vascular choroidal changes in the after-cataract surgery are important. In this study, it was observed that after uneventful phacoemulsification, the choroidal thickness increased at the first postoperative month and reached the preoperative values at the third month. It was also determined that CVI increased at the first and third postoperative months. CVI can offer an idea about whether cataract surgery is a predisposing factor in diseases involving the choroid. Abbreviations: CVI = choroidal vascular index.

Macular Alteration of Topical Diclofenac Sodium after Phacoemulsification Surgery in Diabetic Patients

BACKGROUND: Cystoid macular edema (CME) is a serious complication of cataract surgery in a diabetic patient. CME was found 1–19% after phacoemulsification surgery. Nonsteroidal anti-inflammatory drugs inhibit cyclooxygenase-1, cyclooxygenase-2, and endoperoxides. Inhibition of these enzymes also reduces macular thickening. AIM: The aim of the study was to assess macular thickness alteration after application of 1.00 mg diclofenac sodium eye drops in diabetic patients who receive phacoemulsification surgery. METHODS: This study was a quasi-experimental study. A total of 40 eyes diabetic retinopathy patients having phacoemulsification surgery were randomized to 100 mg diclofenac sodium (n = 20) or placebo eye drops (n = 20), three drops daily on 1 day before surgery until 30 days post-operative. The main outcome measures macular thickness using Ocular Coherence Tomography before and after (14 and 30 days) phacoemulsification. RESULTS: Utilizing an independent t-test, this study had significantly inner macular (p = 0.0001) and central macular (p = 0.008) thickness differences in the diclofenac sodium group during surgery until 14 days postoperatively. However, significant changes in the outer macular thickness were absent. There were no notable alterations in the center, inner, and outer macular thickness in the diclofenac sodium group until 30 days postoperatively. In the placebo group, no significant changes were found in the macular thickness at every point of time. CONCLUSION: Two statistically significant central and inner macular thicknesses in the diclofenac sodium group until 14 days postoperatively were present. There were no significant changes in the center, inner, and outer macular thickness in the diclofenac sodium group until 30 days postoperatively.

Therapeutic Efficacy of Difluprednate 0.05% Versus Prednisolone Acetate 1% in Controlling Inflammation and Macular Oedema Following Phacoemulsification: An Optical Coherence Tomography-Based Study

BACKGROUND

Topical corticosteroids have been the cornerstone in the management of postoperative inflammation following cataract surgery. Due to potential side effects of the older topical steroids like prednisolone acetate and dexamethasone or betamethasone, newer potent steroids preparation like difluprednate, loteprednol or fluorometholone are now being used at lesser dose and frequency to control inflammation. There is scanty literature on the efficacy of these drugs in preventing inflammation and macular oedema in the Indian population.

PURPOSE

The purpose of this study was to compare the efficacy of difluprednate 0.05% against prednisolone 1% eye drops for control of inflammation following phacoemulsification. The adverse effects of both drugs were also evaluated in this retrospective study.

METHODS

This retrospective cohort study included 181 patients operated for age-related cataracts by a single surgeon at a tertiary referral eye hospital between December 2018 and March 2019. Patients received either difluprednate 0.05% emulsion (n=90 eyes) or prednisolone acetate 1% (n=91 eyes) after phacoemulsification with the same brand intraocular lens (IOL) and same phaco machine. The topical medication was initiated one day postoperatively and continued for six weeks in tapering dosage. Pain score (Visual Analogue Scale, VAS), conjunctival hyperemia, anterior chamber (AC) cell grading, corneal oedema, central retinal thickness, subclinical cystoid macular oedema (SCME), intraocular pressures (IOP) and best-corrected visual acuity (BCVA) were examined after one week and six weeks of cataract extraction.  Results: There was no statistically significant difference observed with regards to pain score (no pain in any patients after six weeks), conjunctival hyperemia (no hyperemia in any patients after six weeks), AC inflammation (no reaction in any patients), central retinal thickness (234.44 ± 35.75µ vs. 234.8 ± 34.99µ, p-value 0.946), SCME (16.67% vs. 13.19%, p-value 0.511), IOP (16.8 vs. 15.47 mmHg, p-value 0.101) and BCVA (BCVA 6/6 in 57.7% vs. 70.32%, p-value >0.05) between both groups. The mean change in IOP in both the groups at one week (0 ± 4.4 vs. 1.87 ± 3.54, p-value 0.0007) and six weeks (-0.01 ± 5.53 vs. 1.88 ± 4.01, p-value 0.004) was significant.  Conclusion: Both the groups were equivalent with regards to their therapeutic efficacy in controlling postoperative inflammation and restoration of vision following phacoemulsification.

Comparison of macular thickness change by optical coherence tomography after uncomplicated cataract surgery in eyes with and without exfoliation syndrome

PURPOSE

To evaluate the effect of exfoliation syndrome (ES) on macular thickness after uncomplicated cataract surgery.

METHODS

87 patients (87 eyes) who underwent uncomplicated cataract surgery were included in the study. Optical coherence tomography (OCT) films were taken in addition to the routine ophthalmologic examination before the surgery and at postoperative 1st week, 1st, 3rd and 6th months. Mean macular thickness, central macular thickness and macular volume values obtained from the 6 × 6 mm macular map in the OCT measurements were recorded. The cases were divided into two groups as Group 1: cases without ES and Group 2: cases with ES. The macular values obtained from the OCT measurements of the two groups were compared with statistical methods.

RESULTS

Eighty-seven eyes were included in the study; while 51 had no ES (Group 1), 36 had ES (Group 2). The mean age of all cases was 66.70 ± 9.13 years. While the mean macular thickness, central macular thickness and macular volume were similar at the preoperative visit and the postoperative 1st week of all cases (each p value > 0.05); these values were higher at the postoperative 1st, 3rd and 6th month compared to the preoperative and the postoperative 1st week values (each p value < 0.05). The highest values were obtained at the postoperative 1st month; while the values of 1st, 3rd and 6th months were statistically similar (each p value > 0.05). No statistically significant difference was observed between Group 1 and Group 2 in terms of macular volume, central macular thickness and average macular thickness in these periods.

CONCLUSION

Exfoliation syndrome has not been evaluated as a risk factor for an increase in macular thickness after uncomplicated cataract surgery.

Evaluation of choroidal thickness changes after phacoemulsification surgery

Purpose

The aim of the study was to analyze the effects of uneventful phacoemulsification surgery on choroidal thickness (CT) using spectral domain optical coherence tomography (SD-OCT).

Methods

In this prospective study, 38 eyes of 38 patients having phacoemulsification surgery were included. All patients underwent detailed ophthalmologic examination, including preoperative axial length (AXL) measurement with optical biometry and intraocular pressure (IOP) measurement preoperatively and 1 month postoperatively. The CT was measured perpendicularly at the fovea and 1.5 mm temporal, 3.0 mm temporal, 1.5 mm nasal, and 3.0 mm nasal using SD-OCT preoperatively and 1 month postoperatively. Changes in the CT after surgery and correlation of this change with age, AXL, preoperative IOP, and IOP change were evaluated.

Results

There was a statistically significant increase in the CT at all regions evaluated. This increment was more prominent in the nasal and subfoveal regions. The IOP decreased significantly 1 month after surgery (16.14±4.94 mmHg vs 13.91±4.86 mmHg; P<0.001). The change in IOP was correlated with the CT changes at all regions, whereas age, AXL, and preoperative IOP had no significant correlations with the changes in CT.

Conclusion

Phacoemulsification surgery may cause significant increase in CT, which is correlated with surgery-induced IOP change in the short term. Long-term follow-up of eyes having phacoemulsification surgery may provide further insight into the effects of cataract surgery on the choroid.

Comparison of the current and a new RTVue OCT software version for detection of ganglion cell complex changes due to cataract surgery

The purpose was to compare the current (6.3) and a novel software version (6.12) of the RTVue-100 optical coherence tomograph (RTVue OCT) for ganglion cell complex (GCC) and retinal nerve fibre layer thickness (RNFLT) changes after phacoemulsification in healthy cataract eyes, and to investigate whether version 6.12, in which image segmentation is improved, provides benefits over version 6.3 for RNFLT and GCC imaging via mild cataract. One eye of 22 consecutive healthy cataract patients were imaged before and 1 month after uncomplicated cataract surgery using RTVue-100 OCT software version 6.3. The images were analysed with both software versions. Signal strength index increased significantly after surgery for both RNFLT and the GCC measurements (p ≤ 0.0015). No difference was seen for any RNFLT parameter between the software versions and time points (p ≥ 0.0140). The GCC values did not differ between the versions either before or after surgery (p ≥ 0.4471), but all increased significantly after surgery with software version 6.12 (p < 0.0001). Neither focal loss volume (FLV) nor global loss volume (GLV) differed between the software versions before and after surgery, respectively, but GLV decreased (improved) significantly after surgery (p = 0.010 and <0.001 for versions 6.3 and 6.12, respectively). Cataract surgery induced similar changes with both software versions, but version 6.12 identified the increase of GCC thickness and the decrease of GLV better than the current version. Although no significant difference between software versions was seen before surgery, our results suggest that version 6.12 may be more precise in measuring GCC parameters than the currently available version.

Viscoat versus Visthesia during phacoemulsification cataract surgery: corneal and foveal changes

Background

Ophthalmic viscosurgical devices (OVDs) are widely used in phacoemulsification cataract surgery to maintain adequate intraocular space, stabilize ocular tissue during the operation and decrease the possible damage of the corneal endothelium. Our study has the purpose to compare the corneal and foveal changes of Viscoat and Visthesia in patients undergoing uneventful phacoemulsification cataract surgery.

Methods

Participants in our study were 77 consecutive patients, who were randomized into two groups based on type of OVD used during phacoemulsification: Viscoat or Visthesia. All patients underwent a complete ophthalmological examination i.e., measurement of best corrected visual acuity (BCVA) by means of Snellen charts, intraocular pressure examination by Goldmann tonometry, slit lamp examination, fundus examination, optical coherence tomography, specular microscopy and ultrasound pachymetry preoperatively and at three time points postoperatively (day 3, 15, 28 postoperatively). The differences in baseline characteristics, as well as in outcomes between the two groups were compared by Mann-Whitney-Wilcoxon test and Student's t-test, as appropriate.

Results

Intraoperatively, there was no statistically significant difference in the duration of the ultrasound application between the two groups, while Viscoat group needed more time for the operation performance. It is also worthy to mention that Visthesia group exhibited less intense pain than patients in Viscoat group. Postoperatively, there was a statistically significant difference in central corneal thickness, endothelial cell count and macular thickness between the two groups, but BCVA (logMAR) did not differ between the two groups.

Conclusions

Our study suggests that Viscoat is more safe and protective for the corneal endothelium during uneventful phacoemulsification cataract surgery, while Visthesia is in superior position regarding intraoperative pain. Patients of both groups acquired excellent visual acuity postoperative. Finally, this is the first study comparing OVDs in terms of macular thickness, finding that Visthesia cause a greater increase in macular thickness postoperatively than Viscoat, although it reaches normal ranges in both groups.