Evaluation of Angle Closure as a Risk Factor for Reduced Corneal Endothelial Cell Density

Effect of elevated irrigation bottle height during cataract surgery on corneal endothelial cells in porcine eyes

BACKGROUND

Cataract surgery induces corneal endothelial cell loss (ECL). This study investigates the relationship between bottle height (BH) and ECL induced due to irrigation and aspiration (I/A) in cataract surgery and quantifies protective effects of intraoperatively used ophthalmic viscoelastic substances.

METHODS

Intermittent I/A without phacoemulsification was performed in porcine eyes for 10 min with varying BHs of 100 cm (BH100), 125 cm (BH125), 150 cm (BH150) or no treatment (control, no I/A). Additionally, in one group a dispersive ophthalmic viscoelastic substance was injected into the anterior eye chamber before treatment with I/A at a BH of 150 cm (BH150 + V). After exposure of the corneal endothelium to I/A, the corneas were prepared to split corneal buttons on day 0 and cultivated for 15 days. Endothelial cell density (ECD) was analyzed blinded on days 1, 8 and 15.

RESULTS

Relative ECL significantly correlated with irrigation BH (control (n = 13): -9.69 ± 6.03% (average ± standard deviation); BH100 (n = 12): -9.69 ± 4.81%-p = 1.000; BH125 (n = 14): -19.44 ± 7.30% - p < 0.001; BH150 (n = 13): -21.99 ± 6.70%-p < 0.001). I/A-induced ECL was significantly decreased by the injection of ophthalmic viscoelastic, as BH150 + V (n = 14; -10.92 ± 4.09%-p = 1.000) showed a cell loss comparable to the control group.

CONCLUSIONS

ECL is altered by I/A BH and reduced when viscoelastic substances are used.

Safety and Efficacy of Rapid Primary Phacoemulsification on Acute Primary Angle Closure with and without Preoperative IOP-Lowering Medication

This study aimed to investigate the safety and efficacy of rapid primary phacoemulsification in patients with acute primary angle closure (APAC) (n = 41), with or without preoperative IOP-lowering medication. The best-corrected visual acuity (BCVA), intraocular pressure (IOP), number of corneal endothelial cells (CECs), and number of IOP-lowering medications at the preoperative examination (Pre), postoperative day 1 (1d), week 1 (1w), and month 1 (1m) were used as indicators and compared. BCVA significantly improved at 1d, 1w, and 1m compared with Pre (p < 0.05) and significantly improved at 1m compared to 1d (p < 0.05) for all eyes. IOP significantly decreased at 1d, 1w, and 1m compared with Pre (p < 0.05). CECs were not significantly different between Pre and 1m; the number of IOP-lowering medications decreased significantly from Pre to 1m (p < 0.05). BCVA and IOP were not significantly different between the two groups for all periods. CECs were not significantly different between the two groups at Pre and 1m. Rapid primary phacoemulsification improved visual acuity due to improvement of corneal edema without central visual field defects and good IOP control without reoperation or IOP-lowering medication and maintained the number of corneal endothelial cells with or without preoperative IOP-lowering medication in patients with APAC.

Corneal Endothelial Cell Loss in Glaucoma and Glaucoma Surgery and the Utility of Management with Descemet Membrane Endothelial Keratoplasty (DMEK)

The corneal endothelium has a crucial role in maintaining a clear and healthy cornea. Corneal endothelial cell loss occurs naturally with age; however, a diagnosis of glaucoma and surgical intervention for glaucoma can exacerbate a decline in cell number and impairment in morphology. In glaucoma, the mechanisms for this are not well understood and this accelerated cell loss can result in corneal decompensation. Given the high prevalence of glaucoma worldwide, this review aims to explore the abnormalities observed in the corneal endothelium in differing glaucoma phenotypes and glaucoma therapies (medical or surgical including with new generation microinvasive glaucoma surgeries). Descemet membrane endothelial keratoplasty (DMEK) is increasingly being used to manage corneal endothelial failure for glaucoma patients and we aim to review the recent literature evaluating the use of this technique in this clinical scenario.

A comparative study on endothelial cell loss in nanophthalmic eyes undergoing cataract surgery by phacoemulsification

Purpose:

The purpose of this study is to compare the endothelial cell loss (ECL) in nanophthalmic eyes and age-matched controls undergoing cataract surgery by phacoemulsification and also to identify the risk factors influencing the endothelial cell density (ECD). This was a prospective comparative interventional case series.

Methods:

We enrolled 19 nanophthalmic eyes (study group) and 42 age-matched cataract controls (control group) undergoing phacoemulsification after meeting the inclusion criteria. Ocular parameters like best-corrected visual acuity, intraocular pressure, pachymetry, specular microscopy, and slit lamp findings were noted preoperatively and at month 1 and 3 postsurgery. All nanophthalmic eyes underwent cataract surgery with concomitant prophylactic posterior sclerostomy.

Results:

The median percentage endothelial loss in nanophthalmic eyes was 4.0 (IQR 0–23.5), 7.4 (IQR 1.0–-22.4) at 1 and 3 months postoperatively compared to 6.3 (IQR 1.7–14.1) and 6.4 (IQR 2.6–-12.1) in age controlled normal eyes (P = 0.94, P = 0.46, respectively). Linear regression analysis showed increasing age as the only variable influencing the percentage decrease in corneal ECD in the study group (P = 0.001). Nanophthalmic eyes with ACD <2.5 mm had a significantly greater reduction in ECD at 3 months postcataract surgery compared to baseline (P = 0.039). Visual outcomes and IOP reduction in the study group with ACD >2.5 mm were significantly better postcataract surgery (P = 0.02 and P = 0.002, respectively).

Conclusion:

The percentage of ECL in nanophthalmic eyes undergoing phacoemulsification is equivalent to normal eyes. However, in the nanophthamic eyes with AC depth <2.5 mm, the percentage cell loss was significantly higher warranting the need for extensive intraoperative care. Increasing age was found to be the only significant risk factor influencing the ECD in short eyes.

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.

Factors associated with endothelial cell density loss post Descemet membrane endothelial keratoplasty for bullous keratopathy in Asia

PURPOSE

To investigate the factors associated with endothelial survival after Descemet's membrane endothelial keratoplasty (DMEK) in eyes of Asian patients with bullous keratopathy (BK).

METHODS

In this retrospective, consecutive interventional case series, 72 eyes of 72 patients who underwent DMEK were evaluated. Best corrected visual acuity (BCVA) and corneal endothelial cell density (ECD) were assessed at 12 months postoperatively. Multiple regression analysis was performed to assess parameters such as age, sex, axial length, preoperative visual acuity, re-bubbling, the ratio of graft to cornea area, iris damage scores, types of filling gases, air or SF6 volume in the anterior chamber (AC) on postoperative day 1, and ECD loss rates at 12 months postoperatively.

RESULTS

BCVA improved significantly at 12 months after DMEK (P < .001). The rate of ECD loss at 12 months after DMEK was 54.4 ± 16.1%. Multiple linear regression analysis showed that a larger ratio of graft to corneal area (P = 0.0061) and higher donor ECD (P = 0.042) were the primary factors for a lower ECD loss rate at 12 months after DMEK.

CONCLUSION

A relatively larger graft size compared to the host cornea and more donor ECD might help endothelial survival in patients with BK. Moreover, for such patients, the surgeon should attempt to use a relatively larger graft size when performing DMEK, particularly in Asian eyes.

Long-term effect of YAG laser iridotomy on corneal endothelium in primary angle closure suspects: a 72-month randomised controlled study

PURPOSES

To evaluate the effect of YAG laser peripheral iridotomy (LPI) on corneal endothelial cell density (ECD) and morphology in primary angle closure suspects (PACS) over 72 months.

METHODS

The Zhongshan Angle Closure Prevention Trial is a single-centre randomised controlled trial. Subjects with bilateral PACS received YAG LPI prophylactic treatment in one eye randomly, while the fellow eye served as control. Central corneal ECD and morphology were assessed using non-contact specular microscopy (SP-2000P, Topcon) at baseline, 6, 18, 36, 54 and 72 months postoperatively. Mixed model analysis was conducted to compare the difference between treated and fellow eyes.

RESULTS

A total of 875 participants were included, with a mean age of 59.3±5.0 years and 83.5% female. The ECD declined significantly (p<0.001) over time in both treated and fellow eyes, but the treated eyes showed more progressive cell loss with increasing time (p<0.001). The difference in ECD loss between LPI-treated and fellow eyes was not significant at each follow-up until 72 months (4.9% in LPI eyes vs 4.2% in non-LPI eyes, p=0.003). Mean cell areas increased significantly over time in both treated and fellow eyes (p<0.001), but no longitudinal change was observed for hexagonality. In LPI-treated eyes, no significant correlation was found between age, gender, ocular biometrics, intraocular pressure and laser settings with endothelium change, except for time effect (p<0.01).

CONCLUSION

ECD decreases over time primarily due to ageing effect. YAG LPI does not appear to cause clinically significant corneal endothelial damage over 72 months after treatment.

TRIAL REGISTRATION NUMBER

ISRCTN45213099.

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.

Evaluation of Early Postoperative Intraocular Pressure for Success after Ex-Press Surgery

Aim

The aim of this study is to identify target levels of early postoperative intraocular pressure (IOP) associated with successful trabeculectomy using an Ex-Press glaucoma shunt.

Materials and methods

This was a retrospective single-facility study. We enrolled 158 glaucoma patients who underwent trabeculectomy with Ex-Press and were followed for >1 year, and investigated risk factors for the failure of Ex-Press surgery. We examined age, sex, central corneal thickness (CCT), number of preoperative glaucoma medications, simultaneous performance of cataract surgery, history of trabeculotomy, hypertension (HT), diabetes mellitus (DM), subtype of glaucoma, and early postoperative IOP (minimum, 2 weeks, 1 month, and 3 months).

Results

Ex-Press surgery could significantly decrease IOP. Success rates at 1, 2, 3, and 4 years were 91.1, 86.1, 82.5, and 78.1%, respectively. Factors significantly affecting the success rate included age, the number of preoperative glaucoma medications, and early postoperative IOP. The IOP cutoff values of minimum IOP for the success of Ex-Press surgery was 5 mm Hg.

Conclusions

Younger age, a high number of preoperative glaucoma medications, and high IOPs in the early postoperative period were found to be the risk factors for failure of Ex-Press surgery. Considering hypotonic complications, it is desirable to control the minimum IOP from 3–5 mm Hg within 2 weeks after surgery. According to our calculations, target IOPs at 2 weeks, 1 month, and 3 months after Ex-Press surgery should be 8 mm Hg, 10 mm Hg, and 14 mm Hg, respectively.

Clinical significance

We thought that Ex-Press surgery might require lower IOP in the early postoperative period than conventional trabeculectomy.

How to cite this article

Tojo N, Hayashi A, et al. Evaluation of Early Postoperative Intraocular Pressure for Success after Ex-Press Surgery. J Curr Glaucoma Pract 2019;13(2):55–61.

Central and Peripheral Corneal Endothelial Cell Analysis With Slit-Scanning Wide-Field Contact Specular Microscopy: Agreement With Noncontact Specular Microscopy

PURPOSE

The prospective case series aimed to examine the agreement between the use of a slit-scanning contact specular microscope and a noncontact specular microscope in corneal endothelial cell (CEC) analysis and to evaluate the differences between the central and peripheral regions in normal corneas.

METHODS

After confirming normal corneal endothelium with slit-lamp microscopy, CEC images of 56 eyes of 56 cataractous patients were analyzed in the central and 4 peripheral regions using a slit-scanning contact specular microscope. A noncontact specular microscope was used for the analysis in the central region. The endothelial cell density (ECD), the percentage of hexagonal shape cells (HEX), and the coefficient of variation (CV) in the central region were compared. Differences between central and peripheral CECs were also evaluated.

RESULTS

The mean ECD was 2778 cell/mm and was not different from the results using the noncontact specular microscope (2736 cell/mm, P = 0.051). There was a significant correlation (P < 0.001, R = 0.72). The analysis of HEX resulted in larger values with the slit-scanning contact microscope (53.13% vs. 48.89%, P < 0.001), whereas there was no difference in the CV (38.48 vs. 38.04, P = 0.56). On comparing the central and peripheral regions, there was no significant difference in the ECD, whereas significant differences were found in the superior region in the HEX and CV (P < 0.001) and in the nasal region in CV (P = 0.023).

CONCLUSIONS

The analysis of ECD with the use of the slit-scanning contact specular microscope did not differ from the noncontact specular microscope, and the results demonstrated no difference between the central and peripheral ECD.

Characteristics of the Corneal Endothelium Across the Primary Angle Closure Disease Spectrum

Purpose

To evaluate the corneal endothelial characteristics across the primary angle closure (PAC) disease spectrum amongst patients diagnosed as PAC suspects (PACS), PAC, PAC glaucoma (PACG), and previous acute PAC (APAC).

Methods

We analyzed a total of 529 subjects (51 PACS, 170 PAC, 234 PACG, and 74 with previous APAC). All subjects had undergone laser peripheral iridotomy prior to study recruitment. Corneal endothelial parameters were measured using a noncontact specular microscope and the following parameters were obtained: mean central endothelial cell density (ECD; cells/mm2), coefficient of variation (CV) in cell area, and percentage of hexagonal cells.

Results

The mean age of the subjects was 65.1 ± 8.2 years, and 55.2% were females. The mean central ECD was 2582.0 ± 472.8 cells/mm2 in PACS, 2566.0 ± 408.3 cells/mm2 in PAC, 2523.8 ± 406.8 cells/mm2 in PACG, and 2504.0 ± 558.1 cells/mm2 in APAC, with no significant differences in ECD across the subgroups (P = 0.61). The CV was lowest in PACS (34.38 ± 6.05 μm2/cell), and highest in APAC (37.61 ± 7.98 μm2/cell), but the differences were not significant (P = 0.07). Likewise, the percentage of hexagonality was not significantly different between the groups. A subgroup analysis on the eyes with previous APAC with their fellow eye also showed no significant differences in the corneal endothelial characteristics.

Conclusions

The corneal ECD and morphological characteristics such as CV and hexagonality are not significantly different across the PAC disease spectrum. This may reflect the lack of a sustained and/or dramatic IOP insult and/or an insignificant deleterious effect from medications, age, and chronicity on corneal endothelial parameters.