Corneal Outcomes Following Cataract Surgery Using Ophthalmic Viscosurgical Devices Composed of Chondroitin Sulfate-Hyaluronic Acid: A Systematic Review and Meta-Analysis

Background

Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT).

Methods

MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT^®, DuoVisc^® or DisCoVisc^®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs.

Results

A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: -4.10%; 95% CI: -5.81 to -2.40; p < 0.0001; 9 studies) and HPMC (MD: -6.47%; 95% CI: -10.41 to -2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: -3.22%; 95% CI: -6.24% to -0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: -0.43% to 0.95%; p = 0.4; 2 studies).

Conclusion

CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.

Impact of Ophthalmic Viscosurgical Devices in Cataract Surgery

Background

Ophthalmic viscoelastic devices (OVDs) used during small-incision cataract surgery have numerous advantages. However, OVDs have longer retention time in an eye after surgery resulting in intraocular pressure (IOP) spikes. The purpose of this study is to analyze and quantify the effect of various OVDs on both IOP and best corrected visual acuity (BCVA) by systematically reviewing the literature and performing meta-analysis.

Methods

Numerous databases from January 1, 1985, to present were systematically searched. Thirty-six (3893 subjects) of 3313 studies identified were included for analysis. Standardized mean difference (SMD) was computed, and meta-analysis was performed.

Results

A total of 3313 records were retrieved including 1114 from database search and 2199 from grey literature search. Significant increase in postoperative IOP in 1-day follow-up with Healon (SMD = 0.37, CI: [0.07, 0.67]), Viscoat (SMD = 0.29, CI: [0.13, 0.45]), Provisc (SMD = 0.46, CI: [0.17, 0.76]), and Soft Shell (SMD = 0.58, CI: [0.30, 0.86]) was computed. On the other hand, results implied a nonsignificant increase in postoperative IOP with Healon GV (SMD = 0.07, CI: [−0.28, 0.41]), Healon5 (SMD = 0.15, CI: [−0.33, 0.64]), 2% HPMC (SMD = 0.32, CI: [−0.0, 0.64]), and OcuCoat (SMD = 0.26, CI: [−0.37, 0.9]). Additionally, a nonsignificant reduction in postoperative IOP was inferred with Viscoat + Provisc (SMD = −0.28, CI: [−2.23, 1.68]).

Conclusion

Improvement in IOP was shown with Viscoat + Provisc. Additionally, IOP nonsignificant upsurge was observed with Healon GV, Healon5, 2% HPMC, and OcuCoat compared to significant upsurge with Healon, Viscoat, and Soft Shell.

Changes in corneal endothelial density following scleral buckling surgery for rhegmatogenous retinal detachment: a retrospective cross-sectional study

BACKGROUND

To investigate the effect of scleral buckling (SB) on the morphology and density of human corneal endothelial cells (HCEC).

METHODS

In this retrospective cross-sectional study, 26 patients who had undergone SB due to rhegmatogenous retinal detachment were enrolled, in which 15 patients received encircling while the other 11 segment types of SB. The postoperative status of affected eye, preoperative status of affected eye, and the contralateral healthy eye was served as the study, control and contralateral groups. The images of the corneal endothelium was obtained by specular microscopy at least three months postoperatively and analyzed.

RESULTS

Postoperative best-corrected visual acuity of the study group was worse than that of another two groups (P < 0.001) while intraocular pressure and biometry data were similar. The mean cell area and standard deviation were larger in the study group while the coefficient of variation revealed no difference. The study group manifested a lower endothelial cell density than that of the control and the contralateral (P < 0.001) groups. Concerning the percentage of hexagonal cells, the study group showed a lower hexagonality than the control group (P = 0.04). No difference of the endothelial morphology was found between the segmental subgroup and the encircling subgroup, nor was a significant difference about endothelial cell loss found in the study group with different measurement interval.

CONCLUSIONS

Scleral buckling leads to short-term decreased endothelial cell density and hexagonality, while the rest of morphological features remain unchanged. Moreover, both the segmental and encircling SB procedures yield similar postoperative HCEC status.

Tissue-Inspired Interfacial Coatings for Regenerative Medicine

Biomedical devices have come a long way since they were first introduced as a medically interventional methodology in treating various types of diseases. Different techniques were employed to make the devices more biocompatible and promote tissue repair; such as chemical surface modifications, using novel materials as the bulk of a device, physical topological manipulations and so forth. One of the strategies that recently gained a lot of attention is the use of tissue-inspired biomaterials that are coated on the surface of biomedical devices via different coating techniques, such as the use of extracellular matrix (ECM) coatings, extracted cell membrane coatings, and so on. In this chapter, we will give a general overview of the different types of tissue-inspired coatings along with a summary of recent studies reported in this scientific arena.

Comparison of ExPress Mini-Device Implantation Alone or Combined with Phacoemulsification for the Treatment of Open-Angle Glaucoma

We propose comparative assessment of the effectiveness of two surgical methods for the treatment of open-angle glaucoma: (1) ExPress mini-device implantation combined with phacoemulsification and (2) ExPress mini-device implantation alone. In this prospective study, 81 patients (88 phakic eyes) with uncontrolled open-angle glaucoma enrolled for surgery. They were assigned two groups, those with coexisting cataracts (46 eyes; P-ExPress group) and those with glaucoma alone (42 eyes; ExPress group). The follow-up period was 12.9 ± 0.4 months in P-ExPress and 12.2 ± 0.6 months in ExPress group. In both groups the following parameters were measured: best corrected visual acuity (BCVA), intraocular pressure (IOP), number of complications and necessary postoperative interventions, and number of glaucoma medications. The IOP at the end of follow-up was similar in both groups (18.8 ± 5.9 versus 18.1 ± 4.8 mmHg; P = 0.814). There were no statistical differences in the average number of glaucoma medications between ExPress and P-ExPress groups (0.9 ± 1.65 versus 1.3 ± 1.7; P = 0.419) as well as in the number of postoperative complications (26 versus 21%; P = 0.179 in the P-ExPress and ExPress groups, resp.). Both methods are safe and effective for the surgical treatment of open-angle glaucoma. Coexistence of cataracts does not constitute a compelling contraindication for combined surgery.

Micro- and nanotopography with extracellular matrix coating modulate human corneal endothelial cell behavior

The human corneal endothelium plays an important role in maintaining corneal transparency. Human corneal endothelial cells have limited regenerative capability in vivo. Consequently, endothelial dysfunction can occur following corneal endothelial trauma or inherited diseases. To restore endothelial function, corneal transplantation is needed. However, there is a worldwide shortage of donor corneas, motivating the development of a tissue-engineered graft alternative using cultivated endothelial cells. To induce in vitro cell proliferation, much effort has been made to improve culture conditions and to mimic the native extracellular microenvironment. We incorporated topographical and biochemical cues in our in vitro culture of human corneal endothelial cell line B4G12 (HCEC-B4G12) and hypothesized that manipulation of the extracellular environment can modulate cell proliferation, morphometry and phenotype. The topographies tested were nanopillars, microwells and micropillars on polydimethylsiloxane, while the biochemical factors were extracellular matrix protein coatings of fibronectin-collagen I (FC), FNC® coating mix (FNC) and laminin-chondroitin sulfate (LC). Cellular morphometry, Na(+)/K(+)-ATPase and zona occludens 1 (ZO-1) gene and protein expression were analyzed 3days after cells had formed a confluent monolayer. The cell circularity on all patterns and coatings was above 0.78. On all coatings, cell area was the lowest on micropillars. The coefficient of variation (CV) of the cell area was the lowest on nanopillars with an LC coating. With an FC coating, micropillars induced a better cellular outcome as the cells had the greatest circularity, smallest cell area and highest Na(+)/K(+)-ATPase and ZO-1 gene and protein expression. With the LC coating, HCECs grown on nanopillars resulted in the lowest CV of the cell area and the highest ZO-1 gene expression. Thus, HCEC-B4G12 morphometry and phenotype can be improved using different topographical and biochemical cues.

Intraocular pressure and foveal thickness after phacoemulsification

PURPOSE

To evaluate the natural course of intraocular pressure (IOP) and foveal thickness during the postoperative period, and the correlation between them.

DESIGN

Prospective observational case series.

METHODS

This institutional study comprised 30 eyes of 30 cataract patients scheduled for phacoemulsification. IOP and foveal thickness by optical coherence tomography (OCT) were measured preoperatively and three, six, nine, 12, 15, 18, 21, 24 hours, five days, one month, and two months postoperatively.

RESULTS

The IOP was 4.7 +/- 2.4 mm Hg at three hours postoperatively. The IOP increased to 23.4 +/- 8.1 mm Hg at six hours and 23.5 +/- 7.3 mm Hg at nine hours postoperatively. The IOP was 1.9 mm Hg lower at one month or two months postoperatively than preoperatively. The foveal thickness was 202.1 +/- 19.2 microm and significantly higher at three hours postoperatively, and was 182.3 +/- 20.5 microm, 183.2 +/- 22.3 microm, and significantly lower at nine and 12 hours postoperatively than preoperatively. The correlation between mean IOP and mean foveal thickness is statistically significant. Fovea thickness (microns) = 207.0476 - 1.019759 x IOP (mm Hg), P value < .0001, adjusted R(2) = .8699.

CONCLUSIONS

We found initial hypotony, an IOP spike during six to nine hours, and a decrease of IOP at one month and two months postoperatively. An initial increase of the foveal thickness, a significant reduction at nine hours and 12 hours, and an equivocal increase at one month or two months postoperatively were also noted. A significant negative correlation between IOP and foveal thickness was shown.

Cellular cytotoxicity of antiglaucoma drugs in cultured corneal endothelial cells

In this study, the various antiglaucoma drugs including betaxolol, timolol, levobunolol, carteolol, brimonidine, dipivefrin, dorzolamide, brinzolamide, latanoprost, unoprostone, and pilocarpine were used to investigate the effects of cellular cytotoxicity in cultured bovine corneal endothelial cells. After exposure to the drugs in three dilutions, 1/100, 1/1,000, and 1/10,000, for 100 minutes, cells were estimated based on the release assay of lactate dehydrogenase (LDH) enzyme. It was found that cellular LDH was significantly released in the medium only at 1/100th dilution of betaxolol, brimonidine, dorzolamide, dipivefrin, latanoprost and unoprostone to 130%, 123%, 145%, 157%, 128% and 237%, respectively, compared with controls upon exposure to drugs for 100 minutes. Moreover, benzalkonium chloride preservative at the concentrations ranging from 0.001 to 0.00001 mg/mL did not affect cellular LDH release in bovine corneal endothelial cells. These results indicate that high concentrations of antiglaucoma drugs may induce cytotoxicity in corneal endothelial cells.

Cataract Surgery With Toric Intraocular Lenses Can Optimize Uncorrected Postoperative Visual Acuity in Patients With Marked Corneal Astigmatism

PURPOSE

To study the change in visual acuity and refraction after cataract surgery using a toric posterior chamber intraocular lens in patients with astigmatism after penetrating keratoplasty.

METHODS

A retrospective case note analysis of cataract surgery involving toric lens implants performed at the Norfolk and Norwich University Hospital was conducted. The pre- and postoperative visual acuities and refractions were recorded.

RESULTS

Seven consecutive patients are described (5 men and 2 women) with a mean age of 62 years. They all underwent penetrating keratoplasty, and in every case, all sutures were removed (mean, 11.2 months before cataract surgery). A marked improvement in both unaided visual acuity and astigmatism was shown after the procedure. The average preoperative unaided acuity was 6/120 (range, 6/24 to counting fingers) compared with a postoperative unaided visual acuity average of 6/15 (6/9-6/24). The average preoperative cylinder was 10.12 D (range, 3.40-17.89 D); postoperatively, this fell to 2.75 D (range, 0.75-4.25).

CONCLUSIONS

Cataract surgery with toric intraocular lenses allows the correction of high degrees of regular corneal astigmatism. We discussed the potential advantages and complications of performing toric lens cataract surgery as a secondary procedure.