Risk factors for corneal endothelial cell loss by cataract surgery in eyes with pseudoexfoliation syndrome

Comparison of corneal endothelial cell density reduction between primary open-angle glaucoma and pseudo-exfoliation glaucoma patients at 3 years after Ex-Press® surgery

PURPOSE

We compared corneal endothelial cell (CED) loss after Ex-Press (EXP) surgery between patients with primary open-angle glaucoma (POAG) and pseudo-exfoliation glaucoma (PEX).

PATIENTS AND METHODS

This was a single-facility retrospective study. We included glaucoma patients who had undergone EXP surgery and were followed up > 3 years. We measured the CED before and after (at 12, 24, and 36 months) EXP surgery by noncontact specular microscopy and compared the means of the CED values and CED survival ratios after EXP surgery by paired t-test.

RESULTS

We included 119 eyes that underwent EXP surgery, including 60 POAG eyes and 59 PEX eyes. In the POAG group, the mean CED decreased from 2389 ± 321 at baseline to 2230 ± 424 cells/mm2 after 3 years. In the PEX group, the mean CED decreased from 2111 ± 510 at baseline to 1845 ± 628 cells/mm2 after 3 years. At the 3-year follow-up, the CED survival ratio was 93.3 ± 12.5% in the POAG group and significantly lower, at 85.0 ± 19.5%, in the PEX group (p = 0.0064). Two cases in the PEX group developed bullous keratopathy.

CONCLUSIONS

EXP surgery decreased the corneal endothelial cell populations in PEX patients faster than POAG patients.

Narrative review after post-hoc trial analysis of factors that predict corneal endothelial cell loss after phacoemulsification: Tips for improving cataract surgery research

PURPOSE

Identifying pre/perioperative factors that predict corneal endothelial-cell loss (ECL) after phacoemulsification may reveal ways to reduce ECL. Our literature analysis showed that 37 studies have investigated one or several such factors but all have significant limitations. Therefore, the data of a large randomized controlled trial (PERCEPOLIS) were subjected to post-hoc multivariate analysis determining the ability of nine pre/perioperative variables to predict ECL.

METHODS

PERCEPOLIS was conducted in 2015-2016 to compare two phacoemulsification techniques (subluxation and divide-and-conquer) in terms of 3-month ECL. Non-inferiority between the techniques was found. In the present study, post-hoc univariate and multivariate analyses were conducted to determine associations between ECL and age, sex, cataract density, preoperative endothelial-cell density, phacoemulsification technique, effective phaco time (EPT), and 2-hour central-corneal thickness. The data are presented in the context of a narrative review of the literature.

RESULTS

Three-month data were available for 275 patients (94% of the randomized cohort; mean age, 74 years; 58% women). Mean LOCSIII cataract grade was 3.2. Mean EPT was 6 seconds. Mean ECL was 13%. Only an older age (beta = 0.2%, p = 0.049) and higher EPT (beta = 1.2%, p = 0.0002) predicted 3-month ECL. Cataract density was significant on univariate (p = 0.04) but not multivariate analysis. The other variables did not associate with ECL.

CONCLUSIONS

Older age may amplify ECL due to increased endothelial cell fragility. EPT may promote ECL via cataract density-dependent and -independent mechanisms that should be considered in future phacoemulsification research aiming to reduce ECL. Our literature analysis showed that the average ECL for relatively unselected consecutively-sampled cohorts is 12%.

Corneal endothelial cell loss after EX-PRESS surgery depends on site of insertion, cornea or trabecular meshwork

PURPOSE

Previously, we reported that the Ex-press® shunt (EXP) was associated with more rapid reduction in corneal endothelial cells when inserted into the cornea rather than the trabecular meshwork (TM). We compared the reduction rate of corneal endothelial cells between the corneal insertion group and TM insertion group.

METHODS

This was a retrospective study. We included patients who had undergone EXP surgery and were followed for > 5 years. We analyzed the corneal endothelial cell density (ECD) before and after EXP implantation.

RESULTS

We included 25 patients in the corneal insertion group and 53 patients in the TM insertion group. One patient in the corneal insertion group developed bullous keratopathy. The ECD decreased significantly more rapidly in the corneal insertion group (p < 0.0001), in whom the mean ECD decreased from 2227 ± 443 to 1415 ± 573 cells/mm2 at 5 years with a mean 5-year survival rate of 64.9 ± 21.9%. By contrast, in the TM insertion group, the mean ECD decreased from 2356 ± 364 to 2124 ± 579 cells/mm2 at 5 years, and the mean 5-year survival rate was 89.3 ± 18.0%. The decrease rate of ECD was calculated as 8.3%/year in the corneal insertion group and 2.2%/year in the TM insertion group.

CONCLUSIONS

Insertion into cornea is a risk factor for rapid ECD loss. The EXP should be inserted into the TM to preserve the corneal endothelial cells.

Corneal endothelial wound healing: understanding the regenerative capacity of the innermost layer of the cornea

Currently, there are very few well-established treatments to stimulate corneal endothelial cell regeneration in vivo as a cure for corneal endothelial dysfunctions. The most frequently performed intervention for a damaged or dysfunctional corneal endothelium nowadays is corneal endothelial keratoplasty, also known as lamellar corneal transplantation surgery. Newer medical therapies are emerging and are targeting the regeneration of the corneal endothelium, helping the patients regain their vision without the need for donor tissue. Alternatives to donor tissues are needed as the aging population requiring transplants, has further exacerbated the pressure on the corneal eye banking system. Significant ongoing research efforts in the field of corneal regenerative medicine have been made to elucidate the underlying pathways and effector proteins involved in corneal endothelial regeneration. However, the literature offers little guidance and selective attention to the question of how to fully exploit these pathways. The purpose of this paper is to provide an overview of wound healing characteristics from a biochemical level in the lab to the regenerative features seen in the clinic. Studying the pathways involved in corneal wound healing together with their key effector proteins, can help explain the effect on the proliferation and migration capacity of the corneal endothelial cells.

Endothelial corneal cell damage after pars plana vitrectomy: analogy of different intraocular tamponade agents

A reduction in the corneal endothelial cells multitude after anterior pole intervention is well established in numerous researches, but there are few articles that follow the impact of vitreoretinal interventions on the cornea, especially when endotamponade agents are used. The assessment of the endothelial corneal cells is needed since it facilitates the personal evaluation of the functional endothelial stock. Specular microscopy investigation offers a scale of the functional strength of the endothelium of cornea, which is vital before all intraocular interventions.

Endotamponade agents are very suitable and important tools in the surgical treatment of retinal detachment, but their use must be differentiated depending on the uniqueness of each patient. This research shows corneal endothelial damages caused by intraocular tamponade agents of different types in the case of pars plana vitrectomy for cases of multitude retinal detachments. The purpose of the research was to determine the changes that appear in the endothelium of the cornea and to deal with the results when different tamponade agents are used in the surgical cure for retinal detachment. Specular endothelial corneal microscopy records were achieved and the modifications of the following parameters revealed corneal implication: mean endothelial cell densities, average cell area, coefficient of variation, hexagonality and corneal center thickness. On the first day and at three months postoperatively, a statistically significant reduction was observed for the CV, MCD, and HEX parameters (p 0.001), but no statistically significant difference of the two endotamponade agents (for MCD, p=0.15; for CV, p=0.63; for HEX, p=0.93) was noticed. AVG parameter had a statistically significant decrease (p 0.001) and there was also a statistically significant difference of the two endotamponade agents (p=0.03), patients with gas tamponade presenting a superior result. On the first day and at three months postoperatively, the corneal center thickness presented a statistically significant increase (p 0.001) and there was a statistically significant difference between the two endotamponade agents (p=0.03), patients with gas endotamponade presenting a superior result. In conclusion, using the intraocular tamponade agents helps reestablish the functional-anatomical recovery of the retina after surgery, but their special indication must be well-established for each case of retinal detachment.

Factors influencing the reduction in corneal endothelial cells after Ex-Press® surgery

PURPOSE

We investigated the factors that influence the reduction in corneal endothelial cells after Ex-Press^® surgery.

METHODS

This was a retrospective study. We included patients who had undergone Ex-Press surgery and were followed up for > 2. We analyzed the corneal endothelial cell density (ECD) before and after Ex-Press surgery. We investigated the insertion position (Ex-Press device was inserted into cornea or trabecular meshwork (TM)), Ex-Press-iris touch, cornea-iris touch, peripheral anterior synechiae, history of trabeculotomy, history of selective laser trabeculoplasty, type of glaucoma, and simultaneous cataract surgery as influencing factors. We used multivariate analysis to determine the factors influencing the reduction rate of ECD.

RESULTS

We included 129 eyes. The mean of ECD had decreased 7.0% at 2 years. Ex-Press surgeries significantly decreased the ECD after 2 years (p = 0.0118). As a result of the multivariate analysis, the factor that led to a significantly faster reduction in ECD was the insertion position of the Ex-Press (p < 0.0001). The reduction rate of ECD after 2 years in cases of insertion into the cornea (27 eyes) was 15.1 ± 3.6%, and in cases of insertion into a TM (102 eyes), it was 5.2 ± 1.4%.

CONCLUSIONS

Insertion into the cornea was a risk factor for rapid ECD loss. The Ex-Press should be inserted into a TM for long-term protection of the corneal endothelial cells.

Combined treatment of phacoemulsification and single-port limited pars plana vitrectomy in acute angle-closure glaucoma

AIM

To evaluate the efficacy of combined treatment of phacoemulsification (PE) and micro-incisional single-port transconjunctival limited pars plana vitrectomy (PPV) in acute angle-closure glaucoma (AACG).

METHODS

A retrospective study included 26 patients who underwent PE diagnosed with AACG. Among them, 16 patients (16 eyes) underwent PE alone, 10 patients (10 eyes) underwent combined limited vitrectomy and PE. Then we compared intraocular pressure (IOP), anterior chamber angle, anterior chamber depth, central corneal thickness and corneal endothelial cell count before and after surgery, and effective PE time during cataract surgery.

RESULTS

Effective PE time was shorter in the combined surgery group than in the single surgery group (P=0.040). There was no statistically significant difference in IOP and best-corrected visual acuity between the two groups postoperatively. At 6mo postoperatively, there was no difference in the anterior chamber angle, anterior chamber depth, and central corneal thickness between two groups, but corneal endothelial cell count was higher in the combined surgery group than in the single surgery group (P=0.046). No complication such as vitreoretinal disease, endophthalmitis, bullous keratopathy was noted.

CONCLUSION

Combined micro-incisional single-port transconjunctival limited PPV and PE are more effective and safer than PE alone because of less operation time and fewer complications for management of AACG.

Visual acuity, endothelial cell density and polymegathism after iris-fixated lens implantation

PURPOSE

The purpose of this study was to evaluate the visual acuity as well as endothelial cell density (ECD) and polymegathism after iris-fixated lens (Artiflex® AC 401) implantation for correction of moderate to high myopia.

PATIENTS AND METHODS

In this retrospective cross-sectional study, 55 eyes from 29 patients undergoing iris-fixated lens implantation for correction of myopia (-5.00 to -15.00 D) from 2007 to 2014 were evaluated. Uncorrected visual acuity, best spectacle-corrected visual acuity, refraction, ECD and polymegathism (coefficient of variation [CV] in the sizes of endothelial cells) were measured preoperatively and 6 months postoperatively.

RESULTS

In the sixth month of follow-up, the uncorrected vision acuity was 20/25 or better in 81.5% of the eyes. The best-corrected visual acuity was 20/30 or better in 96.3% of the eyes, and more than 92% of the eyes had a refraction score of ±1 D from the target refraction. The mean corneal ECD of patients before surgery was 2,803±339 cells/mm2, which changed to 2,744±369 cells/mm2 six months after surgery (p=0.142). CV in the sizes of endothelial cells before the surgery was 25.7%±7.1% and six months after surgery it was 25.9%±5.4% (p=0.857).

CONCLUSION

Artiflex iris-fixated lens implantation is a suitable and predictable method for correction of moderate to high myopia. There was no statistically significant change in ECD and polymegathism (CV in the sizes of endothelial cells) after 6 months of follow-up.

Effect of phacoemulsification on intraocular pressure in patients with primary open angle glaucoma and pseudoexfoliation glaucoma

AIM

To compare the effect of phacoemulsification on intraocular pressure (IOP) in patients with primary open angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG).

METHODS

A retrospective comparative case series conducted at the Glaucoma Department at the Association to Prevent Blindness in Mexico. The study enrolled consecutive patients having phacoemulsification with intraocular lens (IOL) implantation and a diagnosis of POAG or PXG. Data about IOP values and number of glaucoma medications used was collected at baseline, 1, 3, 6 and 12mo postoperatively.

RESULTS

The study enrolled 88 patients (88 eyes). After phacoemulsification, there was a statistically significant reduction in IOP values and glaucoma medications use compared to baseline in both POAG and PXG patients (P<0.001). In the POAG group, a 20% decrease in IOP values was evidenced, and a 56.5% reduction in the number of medications used at the one-year follow-up. The PXG group showed a 20.39%, and a 34.46% decrease in IOP and number of medications used, respectively. A significant difference in the mean ΔIOP (postoperative changes in IOP) was evidenced between groups (P=0.005). The reduction of the postsurgical IOP mean values in both groups, the POAG group showed a greater reduction in IOP values compared to the PXG group.

CONCLUSION

In both types of glaucoma, phacoemulsification cataract surgery can result in a significant IOP reduction (20%) over a 12mo follow-up period. The number of medications used is also significantly reduced up to 12mo after surgery, especially in the PXG group.