Risk Factors for Corneal Endothelial Cell Loss in Patients with Pseudoexfoliation Syndrome

Corneal Clarity and Tomographic Patterns in Pseudoexfoliation Syndrome: A Severity-Based Investigation

PURPOSE

The aim of the study was to investigate the corneal and anterior segment characteristics in pseudoexfoliation syndrome (PXS), depending on the severity of the disease.

MATERIALS AND METHODS

This cross-sectional study was conducted at a tertiary care hospital, in the ophthalmology department, in Turkey. Pseudoexfoliation syndrome group was classified into three groups. Pseudoexfoliative material on the part of the pupillary border was classified as group 1, on the entire pupillary border was classified as group 2, and pseudoexfoliative material on the entire pupillary border and iris surface was classified as group 3. The control group was composed of age and gender-matched individuals who had undergone a completely normal ophthalmologic examination. Scheimpflug tomography was performed to record tomographical data.

RESULTS

The PXS groups 1, 2, and 3, along with the control group, consist of 29, 32, 33, and 42 participants, respectively. There was no significant difference in age-gender distribution between patients and the control group (P>0.05). Group 3 showed significant differences in central corneal thickness compared with the control group (P=0.001). In addition, anterior chamber angle was found to be significantly lower in group 3 than the control group (P<0.001). In corneal densitometry (CD) values, significant increases compared with the control group were observed in groups 2 and 3 across all anterior annuli (P<0.001). In group 1, significant increases observed in the anterior 6-10 mm and 10-12 mm annuli (P<0.001). In the middle 6-10 mm annuluses, only group 3 showed a significant increase compared with the control group (P<0.001). In the posterior 0-2, 2-6, and 6-10 mm annuli, significant increases compared with the control were observed only in groups 2 and 3 (P=0.001, P=0.001, P<0.001, respectively).

CONCLUSIONS

Corneal densitometry values, even without an increase in intraocular pressure, have a tendency to increase in PXS depending on the severity of the disease. While minimal changes were observed in the middle layer, it was particularly noted that the effects of the disease were more prominent in the peripheral cornea.

Systemic Vascular Parameters in Ocular Pseudoexfoliation

Background Pseudoexfoliation syndrome (PEX) is characterized by a dandruff-like substance in the anterior chamber, composed of various glycoproteins that have an unclear origin. Its deposition is observed on the pupillary margin, lens zonules, and trabecular meshwork. Proteomic studies have identified numerous proteins in the affected individuals, suggesting associations with systemic conditions like heart disease, stroke, and Alzheimer's disease. However, the systemic associations of PEX remain inconclusive, particularly in regions like southern India. Materials and methods A cross-sectional study was conducted on 114 participants. Pseudoexfoliation was graded as mild, moderate, and severe as per standard photographic grading. Systemic examinations included blood pressure measurements, electrocardiography (ECG), and blood investigations for serum lipid profile, fasting and postprandial blood sugar levels, and serum C-reactive protein levels. Small incision cataract surgery was performed for all the patients. Intraoperative complications and postoperative status were recorded. Results Thirty-eight patients (33.3%) had mild PEX, 44 (38.6%) had moderate PEX, and 32 (28.1%) had severe PEX. Hypertension was present in 54 participants (47.4%), diabetes in 21 (18.4%), coronary artery disease in nine (7.9%), and cerebrovascular accidents in three (2.6%). The mean systolic blood pressure was 140.39 mmHg and the mean diastolic blood pressure was 90.37 mmHg. Systolic blood pressure exceeded 140 mmHg in 29 participants (90.6%) with severe PEX, while diastolic blood pressure surpassed 90 mmHg in 26 participants with severe PEX, both with a p-value of 0.001. Mean fasting and postprandial blood sugar levels were 103.80 ± 31.81 mg/dl and 131.72 ± 48.24 mg/dl, respectively. Serum lipid profiles showed mean low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), cholesterol, and triglyceride levels of 103.00 ± 34.49 mg/dl, 29.04 ± 15.51 mg/dl, 172.73 ± 43.34 mg/dl, and 129.33 ± 64.65 mg/dl respectively. Electrocardiographic results indicated that 54 participants (47.37%) had abnormal ECG including rate abnormality in 13.2%, conduction defects in 12.3%, ischemic changes in 10.5%, and structural defects in 11.4%. Eighty-seven percent of patients had non-dilating pupils and iris atrophy, 13.2% had zonular dialysis and intraoperatively, 78% had capsulorhexis extension, 49.12% had difficult nucleus prolapse, and 28.95% had posterior capsular rent. Conclusion This study highlights the significantly elevated parameters of systemic vascular diseases in PEX patients, like elevated blood pressure and more frequent cardiac anomalies, emphasizing the need for comprehensive systemic evaluation and careful preoperative assessment for ocular comorbidities.

Comparison between primary Ahmed valve implantation and primary trabeculectomy with mitomycin C in pseudophakic patients with exfoliative glaucoma

PURPOSE

To compare the efficacy and safety of primary Ahmed valve implantation (AVI) and primary trabeculectomy with mitomycin C (MMC) in patients with pseudophakic exfoliative glaucoma (XFG).

METHODS

All enrolled patients were divided into two groups: the TRAB group, comprising patients who underwent trabeculectomy with MMC, and the AVI group, comprising patients who underwent AVI. Intraocular pressure (IOP), mean deviation (MD), endothelial cell density of cornea (ECD), and the number of topical anti-glaucoma agents used during study period were retrospectively analyzed. Surgical success rates were compared between two groups using Kaplan-Meier survival analysis. Three levels of surgical success were defined as follows: (1) IOP ≤ 18 mmHg and an IOP reduction of 20% without medication; (2) IOP ≤ 15 mmHg and an IOP reduction of 25% without medication; and (3) IOP ≤ 18 mmHg and an IOP reduction of 20%, irrespective of medication.

RESULTS

The TRAB and AVI groups comprised 40 and 36 patients, respectively. At 36 months postoperatively, IOP was 15.7 ± 2.8 mmHg in the TRAB group and 16.9 ± 3.3 mmHg in the AVI group (p = 0.140). Surgical success rates in the TRAB group were 47.5, 37.5, and 77.5% and those in the AVI group were 41.6, 33.3, and 75.0% at 36 months for surgical criteria 1, 2, and 3, respectively. There were no statistically significant differences in the success rates between the two groups. However, regarding surgical criteria 2, the success rate of the AVI group at 1 year was significantly better than that of the TRAB group (p = 0.030).

CONCLUSIONS

Primary AVI was not inferior to primary trabeculectomy with MMC in medically uncontrolled patients with XFG.

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.

Risk factors for fluctuations in corneal endothelial cell density (Review)

The cornea is a transparent, avascular and abundantly innervated tissue through which light rays are transmitted to the retina. The innermost layer of the cornea, also known as the endothelium, consists of a single layer of polygonal endothelial cells that serve an important role in preserving corneal transparency and hydration. The average corneal endothelial cell density (ECD) is the highest at birth (~3,000 cells/mm²), which then decrease to ~2,500 cells/mm² at adulthood. These endothelial cells have limited regenerative potential and the minimum (critical) ECD required to maintain the pumping function of the endothelium is 400-500 cells/mm². ECD < the critical value can result in decreased corneal transparency, development of corneal edema and reduced visual acuity. The condition of the corneal endothelium can be influenced by a number of factors, including systemic diseases, such as diabetes or atherosclerosis, eye diseases, such as uveitis or dry eye disease (DED) and therapeutic ophthalmological interventions. The aim of the present article is to review the impact of the most common systemic disorders (pseudoexfoliation syndrome, diabetes mellitus, cardiovascular disease), eye diseases (DED, uveitis, glaucoma, intraocular lens dislocation) and widely performed ophthalmic interventions (cataract surgery, intraocular pressure-lowering surgeries) on corneal ECD.

Dynamic volume-rendered optical coherence tomography pupillometry

PURPOSE

To assess intrapupillary space (IPS) changes in healthy subjects with regard to decreased iris motility in patients with pseudoexfoliation glaucoma (PEXG) or non-arteritic anterior ischaemic optic neuropathy (NAION) in a feasibility study in a clinical environment.

METHODS

Scotopic and photopic IPS measurements using three-dimensionally rendered swept-source optical coherence tomography (SS-OCT) data were obtained and compared for all subjects. Intrapupillary space (IPS) parameters were evaluated such as absolute volumetric differences, relative light response for volumetric ratios and pupillary ejection fraction (PEF) for functional contraction measurements.

RESULTS

From a total of 122 IPS from 66 subjects, 106 IPS were eligible for comparison providing values for 72 normal, 30 PEXG and 4 NAION eyes. In healthy, PEXG and NAION subjects, scotopic overall mean IPS was 8.90, 3.45 and 4.16 mm³ , and photopic overall mean IPS was 0.87, 0.74 and 1.13 mm³ , respectively. Three-dimensional contractility showed a mean absolute difference of 8.03 mm³ for normals (defined as 100% contractility), 2.72 mm³ for PEXG (33.88% of normal) and 3.03 mm³ for NAION (38.50% of normal) with a relative light response ratio between scotopic and photopic volumes of 10.26 (100%), 4.69 (45.70%) and 3.67 (35.78%), respectively. Pupillary ejection fraction (PEF) showed a contractile pupillary emptying of 88.11% for normals, 76.92% for PEXG and 70.91% for NAION patients.

CONCLUSION

This 3D pupillometry OCT assessment allows for quantitative measurements of pupil function, contractility and response to light. More specifically, PEF is presented as a potential (neuro)-pupillary outcome measure that could be useful in the monitoring of ophthalmic disorders that affect pupillary function.

Consequences of mechanical pupil dilation, a study based on the Swedish national cataract register

PURPOSE

To describe the outcomes and demographics of patients undergoing mechanical pupil dilation (MPD) during cataract surgery.

SETTING

All cataract procedures performed in Umeå University Hospital and Sunderbyn, Gällivare and Piteå hospitals reported to the Swedish National Cataract Register (NCR) during 2013-2019.

DESIGN

Retrospective cohort study based on the Swedish NCR and electronic patient records.

METHODS

The number of control visits, pre- and postoperative visual acuities, surgical complications/intraoperative difficulties, ocular comorbidities and postoperative treatment regimens were retrieved for all cataract procedures with MPD. For each procedure, the consecutive procedure in the NCR from the same clinic without MPD was chosen to form a control group. A multinominal regression analysis with MPD as the dependent variable was performed to identify factors and outcomes independently associated with MPD.

RESULTS

A total of 25 349 patients aged 18-97 years underwent cataract surgery in these hospitals during the study period. Of these, 653 (2.6%) had MPD. Factors such as pseudoexfoliations and capsule staining were over-represented among MPD eyes. As a group, eyes with MPD had more postoperative visits and more postoperative anti-inflammatory drops, and more frequently needed augmentation of the anti-inflammatory treatment at the first postoperative visit.

CONCLUSIONS

MPD is independently associated with a more complicated intra- and postoperative course with more follow-up visits and requires more anti-inflammatory treatment postoperatively. This information could be added to the postoperative counselling, and more postoperative anti-inflammatory treatment could be considered in cases with MPD.

The effects of trypan blue use on the corneal endothelium during cataract surgery in patients with pseudoexfoliation syndrome (PEX)

PURPOSE

In the present clinical study, it was aimed to investigate the possible effects of Trypan blue (TB) use on the corneal endothelium during cataract surgery in eyes with pseudoexfoliation syndrome (PEX) during a three-month follow-up period using the contralateral eye control design.

METHODS

This prospective, randomised controlled, individual cohort study included 92 eyes of 46 patients with bilateral PEX and cataracts. While 1% TB was applied to one eye of the patients before capsulorhexis (study group), it was not applied to the other eye (control group). Both groups were compared preoperatively and postoperatively in terms of endothelial cell density (ECD), endothelial cell loss (%), pleomorphism, polymegathism and central corneal thickness (CCT) using specular microscopy.

RESULTS

Preoperative corneal ECD was measured as 2362.56 ± 253.27 in the study group, 2380.84 ± 220.54 in the control group, and 2145.58 ± 221.71 in the study group and 2184.97 ± 200.94 cells/mm² in the control group in the postoperative 3rd-month follow-up (p = 0.71 and = 0.37, respectively). In addition, there were no significant differences between the two groups in terms of the percentage of hexagonal cells, coefficient of variation (CV), and CCT both preoperatively and postoperatively 3 months later (p = 0.78, =0.39, =0.95 preoperatively and p = 0.31, =0.26, =0.83 postoperatively, respectively).

CONCLUSION

This study demonstrated that the injection of 1% TB into the anterior chamber for staining the anterior capsule during cataract surgery did not cause significant corneal endothelial changes at postoperative 3^rd months, despite the increased fragility of corneal endothelial cells in patients with PEX.

Association Between Anterior Chamber Angle and Corneal Endothelial Cell Density in Chronic Angle Closure

Purpose

To study the association between corneal endothelial cell density (ECD) and degree of anterior chamber angle (ACA) opening in eyes with chronic angle closure glaucoma.

Methods

The study was conducted at JEC Eye Hospitals in Indonesia. Treatment-naïve patients aged ≥40 years with IOP >21 mmHg and peripheral anterior chamber depth (ACD) grade 2 or less by Van Herick's technique were recruited. Trabecular iris angle (TIA; degree) was measured using anterior segment optical coherence tomography (AS-OCT) and classified as: grade 1 ≤10°, grade 2 11-20°, and grade 3 >20°. Noncontact specular microscopy was performed, and the following corneal parameters were obtained:ECD (cells/mm²), coefficient of variation (CV; μm²/cell), percentage of hexagonal cells, and central corneal thickness (CCT; μm).

Results

A total of 52 eyes from 52 subjects were recruited (16 grade 1 TIA, 24 grade 2 TIA, and 12 grade 3 TIA). Presenting IOP was not significantly different between groups. The median central corneal ECD was 2684.5 (1433-2934), 2587.0 (1902-3103), and 2441.0 (1659-3005) cells/mm² in grade 1, 2, and 3 TIA, respectively, with no significant differences across the groups (P = 0.67). The CV was lowest in grade 3 TIA (36.4 ± 7.2 μm2/cell), and highest in grade 1 TIA (38.3 ± 9.6 μm2/cell), but the differences were not significant (P = 0.74). Likewise, the percentage of hexagonality and CCT was not significantly different. TIA was not correlated with IOP but was modestly correlated with age.

Conclusion

The corneal ECD and morphological characteristics such as CV and hexagonality were not significantly different across various TIA grading in chronic angle closure. This may reflect the lack of chronic and gradual IOP insult on corneal endothelial parameters as TIA did not show direct effect towards IOP.

Five-Year Follow-up of First 11 Patients Undergoing Injection of Cultured Corneal Endothelial Cells for Corneal Endothelial Failure

PURPOSE

To report the safety and efficacy of a novel cell injection therapy using cultured human corneal endothelial cells (hCECs) for endothelial failure conditions via the report of the long-term 5-year postoperative clinical data from a first-in-humans clinical trial group.

DESIGN

Prospective observational study.

PARTICIPANTS

This study involved 11 eyes of 11 patients with pseudophakic endothelial failure conditions who underwent hCEC injection therapy between December 2013 and December 2014.

METHODS

All patients underwent follow-up examinations at 1 week, 4 weeks, 12 weeks, and 24 weeks and 1 year, 2 years, 3 years, 4 years, and 5 years after surgery. Specific corneal endothelial cell parameters (i.e., corneal endothelial cell density [ECD], coefficient of variation of area, and percentage of hexagonal cells) and central corneal thickness, best-corrected visual acuity (BCVA) on a Landolt C eye chart, and intraocular pressure (IOP) were recorded.

MAIN OUTCOME MEASURES

The primary outcome was the change in central ECD after cell injection therapy, and the secondary outcome was corneal thickness, BCVA, and IOP during the 5-year-postoperative follow-up period.

RESULTS

At 5 years after surgery, normal corneal endothelial function was restored in 10 of the 11 eyes, the mean ± standard deviation central corneal ECD was 1257 ± 467 cells/mm² (range, 601-2067 cells/mm²), BCVA improved significantly in 10 treated eyes, the mean visual acuity changed from 0.876 logarithm of the minimum angle of resolution before surgery to 0.046 logarithm of the minimum angle of resolution after surgery, and no major adverse reactions directly related to the hCEC injection therapy were observed.

CONCLUSIONS

The findings in this study confirmed the safety and efficacy of cultured hCEC injection therapy for up to 5 years after surgery.