Clinical observation of phacoemulsification under the low perfusion pattern and low negative pressure in patients with low corneal endothelial cell density

BACKGROUND

To observe the safety and effect of phacoemulsification combined with intraocular lens (IOL) implantation in patients with low corneal endothelial cell density (CD) under the low perfusion pattern with low negative pressure.

METHODS

In this retrospective case series study, a total of 16 patients (17 eyes) were studied. They had all been diagnosed with low corneal endothelial (CD) and cataracts in the First Affiliated Hospital of Fujian Medical University from December 2019 to October 2021. They underwent phacoemulsification combined with IOL implantation under the low perfusion pattern with low negative pressure. The variations of corneal endothelial( CD), coefficient of variation (CV) of the cell area, central corneal thickness (CCT), visual acuity, and intraocular pressure before and after the operation were observed and assessed. Then a paired t-test, repeated measures analysis of variance, and Pearson correlation analysis were adopted for data analysis.

RESULTS

The mean intraocular pressure of the 17 eyes was 16.88 ± 6.47 mmHg before the operation and 14.41 ± 3.10 mmHg after the operation, showing a statistically significant difference of t = 2.222, and p = 0.041. Before the operation, the mean visual acuity was 0.16 ± 0.09, and after the operation, it was 0.45 ± 0.16, displaying a statistically significant difference of t = -9.917, p < 0.001. Before and after the operation, four of the 17 eyes had no detectable CD. The mean CD of the other 13 eyes at one month after the operation (644.308 ± 106.24 cells/mm²) was lower than that before the operation (709.62 ± 119.19 cells/mm²), and the differences were statistically significant (F = 20.044, p < 0.001). However, no statistically significant differences were found in the mean CV before the operation (31.23 ± 4.21), and at one month after the operation (32.62 ± 3.80; F = 2.130, p = 0.157). Moreover, the mean CCT of 14 eyes at one month after the operation (562.72 ± 27.82 μm) was larger than that before the operation (534.79 ± 24.69 μm).

CONCLUSIONS

The low perfusion pattern with low negative pressure is safe and effective for corneal endothelial dysfunction patients complicated with cataracts.

Endothelial Cell Density After XEN Implant Surgery: Short-term Data From the Italian XEN Glaucoma Treatment Registry (XEN-GTR)

PRECIS

XEN implant was associated with low endothelial cell density (ECD) reduction. In fact, when combined with phacoemulsification, the reduction in ECD was similar to that expected after phacoemulsification alone.

PURPOSE

The purpose of this study was to assess the impact of XEN implant, either alone or in combination with phacoemulsification, on ECD.

METHODS

Multicenter, prospective, observational study conducted on consecutive open-angle glaucoma patients, who were enrolled in the Italian XEN Glaucoma Treatment Registry and have complete endothelial cell count data at baseline and at 6 months after implantation. The primary endpoint was the mean percentage change in ECD between baseline and month 6.

RESULTS

The study included 108 open-angle glaucoma eyes (68 in the XEN-solo and 40 eyes in the XEN+phaco groups) and 60 control eyes (phaco-solo group). As compared with baseline, mean (95% confidence interval, CI) ECD reduction was -5.6% (-7.0% to -4.9%), -11.3% (-13.8% to -10.9%), and -13.0% (14.8% to -11.8%) in the XEN-solo, XEN+phaco, and phaco-solo groups, respectively (P=0.0004, <0.0001, and <0.0001, respectively). As compared with the XEN-solo group, the ECD reduction was significantly greater in the XEN+phaco group (mean difference=5.7%; 95% CI: 4.1%-7.3%, P<0.0001) and in the phaco-solo group (mean difference=7.4%; 95% CI: 5.7%-9.1%, P<0.0001). ECD reduction was similar in XEN+phaco and phaco-solo groups (P=0.9). In absolute terms, ECD reduction was significantly greater in the XEN+phaco (mean difference=169±306, P=0.021) and in the phaco-solo (mean difference=192±302, P=0.0022) groups than in the XEN-solo group.

CONCLUSIONS

The mean ECD reduction 6 months after XEN implantation was low. The ECD reduction in the XEN+phaco group was larger than in the XEN-solo group but was similar to that observed in the phaco-solo group.

Impact of surgical experience on early post-operative regional corneal thickness after phacoemulsification

Background: Currently, phacoemulsification is a very common cataract surgical procedure in which the lens is emulsified and aspirated from the eye through a small corneal incision.Aim: To compare early regional corneal thickness changes following phacoemulsification done by experienced surgeons versus trainee surgeons.Setting: A prospective cohort study was done at Ibn Al Haitham tertiary eye hospital in Baghdad, Iraq.Methods: The data were collected for 5 months, from 01 March 2018 until 31 July 2018. Adult patients undergoing phacoemulsification and intraocular lens surgery were prospectively evaluated and divided into two groups. Group 1 comprised those operated by experienced surgeons, whilst Group 2 patients were operated by trainee surgeons. Slit lamp examination and endothelial specular microscopy were assessed with the measurement of central corneal thickness (CCT) and peripheral corneal thickness (PCT), using Scheimpflug imaging (Pentacam).Results: There was a significant statistical difference in post-operative CCT between Groups 1 and 2, being 596.72 ± 50.69 µm compared to 631.54 ± 67.84 µm in Groups 1 and 2, respectively, with a mean difference of 34.82 µm (p = 0.000). More difference was observed in post-operative PCT (148.38 µm) as it was 734.8 ± 88.55 µm in the experienced group, compared to 883.18 ± 128.43 µm in the trainee group (p = 0.005).Conclusion: Phacoemulsification done by trainee surgeons was associated with higher CCT and PCT.

Histopathological changes in the anterior segment with anterior and posterior chamber intraocular lens

OBJECTIVE

Patients have shown a lowering of intraocular pressure (IOP) after cataract surgery. Histopathology studies have reported trabecular meshwork (TM) changes in pseudophakic eyes with posterior chamber intraocular lens (PCIOL) and have eluded to the mechanisms for IOP decrease. Unlike PCIOLs, TM histopathology changes after implantation of an anterior chamber intraocular lens (ACIOL) have not been studied, to our knowledge. Therefore, this study aims to examine the histopathological changes in both the TM and corneal endothelium among donor eyes with ACIOL, PCIOL, and phakic eyes.

METHODS

Forty fixed postmortem donor eyes were obtained, sectioned, and embedded. Slides were stained with Masson's trichrome and CD31 vascular endothelial antibody, and further digitalized. Customized Medical Parachute TMAN software quantified the cellular components, the trabecular extracellular matrix (ECM), ECM fibrosis, and trabecular area. Schlemm's canal and corneal endothelium were quantified across the ACIOL, PCIOL, and phakic groups.

RESULTS

Cellular area component of the TM was lower in the ACIOLs and PCIOLs than in phakic eyes, but statistically significant only between PCIOL and phakic eyes (p = 0.0023). ECM area component, TM fibrosis score and TM lamellae area, ciliary process fibrosis, and CD31 expression in Schlemm's canal showed no differences (p = 0.40, 0.99, 0.10, 0.83, 0.45). Significantly lower corneal endothelial cells were seen in ACIOLs compared with both PCIOLs and phakic eyes (p = 0.0002).

CONCLUSIONS

ACIOLs and PCIOLs in our sample group showed that there is loss of cellular components in the TM compared with the phakic eyes, with PCIOLs displaying the least amount of TM cells statistically, in this cohort. The ACIOLs led to a greater loss of corneal endothelial cells than both PCIOLs and phakic eyes after cataract surgery. The endothelial cells in Schlemm's canal did not seem to be affected by the IOL placements. Therefore, this study illustrates that there are histopathological differences seen with the placements of ACIOLs in both TM and cornea.

A 27-Year Report from the Central Eye Bank of Iran

Purpose

To report the 27-year statistical data from the Central Eye Bank of Iran (CEBI) and its activity.

Methods

All CEBI records regarding procured eyes, tissue utilizations, corneal transplants per capita, and indications for keratoplasty from 1991 to 2017 were analyzed.

Results

In total, 115,743 whole eyes were donated during the 27-year period. Out of the 114,169 eyes donated between 1994 and 2017, 95,314 eyes were distributed for transplantation, and 95,057 corneas were actually transplanted. The mean annual rate of corneal transplants per capita was 55.10 - 6 ± 27.10 - 6 . Although penetrating keratoplasty (PKP, 70%) was the most common technique of corneal transplantation during the study period, it exhibited a decreasing trend between 2006 and 2017 (P = 0.048). It was in contrast to Descemet stripping automated endothelial keratoplasty (DSAEK) that demonstrated an increasing trend during the same period (P < 0.001). Keratoconus (KCN, 39.70%) was the most leading indication for keratoplasty over the last three decades followed by bullous keratopathy (BK, 18.5%), corneal scar and opacities (15.7%), and graft failure (GF, 7.5%), with an increasing trend for BK, GF, and KCN. A majority of scleral tissues (83.7%) were utilized for orbital implant protection.

Conclusion

An increasing trend in the number of procured eyes was observed over the past 27 years in Iran. The most leading indications for corneal transplantation were KCN and BK. While PKP was the most common keratoplasty technique, DSAEK showed an increasing trend over the last 12 years.

Changes in corneal thickness and corneal endothelial cell density after phacoemulsification cataract surgery: a double-blind randomized trial

Background

Age-related cataract is a leading cause of visual impairment, considered a global health burden, it is responsible for over 47% of blindness worldwide. Surgical intervention is usually the treatment of choice and phacoemulsification cataract surgery with implantation of an intraocular lens is the most common procedure, which may have several complications.

Objectives

To determine the effects of phacoemulsification surgery on corneal endothelial cell density and corneal thickness in patients undergoing cataract surgery.

Methods

The present study was conducted on patients diagnosed with immature senile cataract requiring surgical intervention from November 2013 to 2014 in Khatam al Anbia Hospital (a tertiary ophthalmology center). Physical examination included best-corrected visual acuity using the Snellen chart, refraction, slit-lamp bio-microscopy for anterior chamber evaluation, keratometry, Goldman tonometry, gonioscopy, and dilated indirect ophthalmoscopy, pachymetry, specular microscopy and biometry. Surgery was performed by similar method and technique in all patients. The change in the corneal endothelial cell count or density and central corneal thickness (CCT) number were compared preoperatively and one day, one week, one month, and three months post–operatively.

Results

A total of 92 eyes of 85 patients (43 females and 42 males with mean age of 62.1±12.2 years) were studied. Patients’ visual acuity improved (log MAR: 1±0.5 preoperatively to 0.45±0.34 post-operatively) (p=0.001). There was 11.4% endothelial cell loss (ECL) and significant decrease in ECC (from 2,791.15±99.86 to 2,472.87±472.14) (p=0.04). The central corneal thickness increased significantly (from 530.47±2.60 to 540.91±36.07). Diabetic patients (12.9%) had a statistically significant higher ECL rate after phacoemulsification (14.6% versus 8.7% respectively, p=0.002).

Conclusion

Phacoemulsification resulted in significant corneal endothelial damage, which is particularly important in patients with a borderline reservoir of endothelial cell, such as diabetic patients, which highlights the necessity of refining the current surgical methods and instruments to minimize the endothelial damage.

Trial registration

The trial was registered in the Thai clinical trial registry (http://www.clinicaltrials.in.th) with the ID: TCTR20171122001.

Funding

The study was supported by a research grant of Mashhad University of Medical Sciences.

Advances in cataract surgery: preserving the corneal endothelium

PURPOSE OF REVIEW

Cataract surgery is known to lead to some degree of corneal endothelial cell loss (ECL). The purpose of this review is to describe how recent technological advancements such as femtosecond laser-assisted cataract surgery (FLACS) affect corneal endothelium during cataract surgery.

RECENT FINDINGS

It has been suggested that FLACS may reduce the amount of required ultrasound energy used in cataract surgery, a factor known to be directly related to ECL. Several recent studies demonstrate either no difference or less ECL with FLACS than with standard phacoemulsification 1-3 months after surgery. However, results at 6 months show comparable ECL between the two techniques. Other recent advancements in surgical technique, such as biaxial microincision surgery, result in similar ECL rates to that of standard phacoemulsification. The use of ultraviolet light in the newly developing light-adjustable intraocular lenses does not increase ECL. Studies show either similar results or less ECL with the use of the newer viscous-dispersives when compared with other viscoelastic devices. Other aspects such as the use of intracameral injections have no adverse effects on corneal endothelium.

SUMMARY

Newly emerging cataract surgical techniques cause comparable ECL to that of conventional phacoemulsification. Femtosecond laser-assistance may reduce ECL, but likely only in the early postoperative period. Further studies are needed to better elucidate short and long-term effects of FLACS on the corneal endothelium. Viscous dispersives may offer equal or increased protection of the corneal endothelium during surgery compared with viscoelastic devices currently in wide use, but further studies are required to support these results.

The changing fate of the corneal endothelium in cataract surgery

PURPOSE OF REVIEW

Corneal endothelial cell loss remains a well known, undesirable side-effect of cataract surgery that may, in severe cases, negatively impact patients' postoperative visual outcomes. This article reviews the current literature and describes in detail how the degree of corneal endothelial cell loss is influenced by specific patient risk factors, as well as the arrival of newer surgical techniques and technologies.

RECENT FINDINGS

Recent studies have demonstrated a reduction in corneal endothelial cell loss after phacoemulsification with the use of viscoelastic materials and modifications in phacoemulsification technology. Some patient characteristics may predispose patients to increased endothelial cell loss during cataract surgery.

SUMMARY

Advances in surgical technique, the implementation of newer surgical technologies such as torsional ultrasound and viscoelastic devices, and aspects of patients' preexisting medical history may lead to varying degrees of endothelial cell loss after cataract surgery. Appropriately addressing these issues during the perioperative period may improve the rate of endothelial cell loss, and thus further enhance the visual outcome of patients undergoing cataract surgery.