Short-term effect of mitomycin-C augmented trabeculectomy on axial length and corneal astigmatism

Effects of intraocular pressure change on intraocular lens power calculation in primary open-angle glaucoma and ocular hypertension

This study aimed to assess the effect of intraocular pressure (IOP) changes on biometry and intraocular lens (IOL) power calculation in patients diagnosed with primary open-angle glaucoma (POAG) and ocular hypertension (OHT). This prospective non-randomized cohort study enrolled patients with diagnosed POAG and OHT, presenting with IOP levels exceeding 25 mmHg. Thai Clinical Trials Registry number was TCTR20180912007. Optical biometry, encompassing measurements such as corneal thickness (CCT), keratometry, anterior chamber depth (ACD), and axial length, was conducted before and after IOP reduction. The IOL power was also determined using the SRK/T formula. The main outcomes measured were alterations in biometry and IOL power. Correlations between IOP, biometric parameters, and IOL power were analyzed. In total, 28 eyes were included in the study, with a mean patient age of 65.71±10.2 years. After IOP reduction, all biometric parameters, except CCT and ACD, exhibited a decrease without reaching statistical significance (all p>0.05). Meanwhile, IOL power showed a slight increase of 0.214±0.42 diopters (P = 0.035). The correlation between IOP and biometric parameters was found to be weak. However, there was a moderate correlation between IOP and IOL power (r2 = 0.267). Notably, IOL power tended to increase by more than 0.5 diopters when IOP decreased by more than 10 mmHg (p < 0.001). In conclusion, changes in IOP among patients with POAG and OHT do not significantly impact biometry and IOL power calculations. Nonetheless, it may be prudent to consider a slight adjustment in IOL power when IOP is lowered by more than 10 mmHg.

No Changes in Keratometry Readings and Anterior Chamber Depth after XEN Gel Implantation in Patients with Glaucoma

Background: This study aimed to compare keratometry and anterior chamber depth (ACD) changes after XEN implantation in primary open-angle glaucoma (POAG) cases over a 3-month follow-up period. Methods: Twenty patients with POAG who underwent XEN63 implantation, either standalone or combined with cataract surgery, were included. Preoperative data, including best-corrected visual acuity (BCVA), refraction, gonioscopy, ophthalmoscopy, intraocular pressure (IOP) evaluation, and axial length, were collected. Corneal topography and ACD measurements were assessed preoperatively and at postoperative days 1, 7, 15, 30, 60, and 90. Each patient's eye that underwent XEN surgery was included in the study group, with the fellow eye serving as a control. Results: In the study group, there was a significant decrease in IOP after XEN stent implantation at all investigated time intervals (p < 0.05). However, changes in mean ACD did not show statistically significant differences at any follow-up examination in both the study and control groups. Additionally, keratometry readings revealed no significant changes in total astigmatism or steep keratometry values in either group. Conclusions: XEN implantation in POAG cases resulted in a significant decrease in IOP over the 3-month follow-up period. However, there were no significant changes observed in mean ACD or keratometry readings, indicating stability in these parameters post-XEN implantation. These findings suggest that XEN implantation may be an effective option for IOP reduction without affecting corneal curvature or ACD in POAG patients.

Reversal of severe myopia by 24 years of hypotony with subsequent stable refraction after 2 years of normal intraocular pressure

Purpose

To report sustained axial length shortening and hyperopic shift (refraction changed from -8 to -2 diopters) induced by 24 years of profound IOP (intraocular pressure) reduction with subsequent refractive stability 2 years after IOP rose to 11-17 mm Hg.

Observations

A 25-year-old woman with elevated episcleral venous pressure glaucoma underwent non-penetrating trabeculectomy and subsequent laser goniopuncture in her left eye. She had chronically low IOP (1-12 mm Hg) for the next 24 years. Hypotony maculopathy was present in postoperative years 13-14 and 18-24 but resolved at age 49 when emesis-induced iris prolapse obstructed the filtering passage and transiently raised IOP to 40. Medical management and iridectomy with flap suturing stabilized IOP between 11 and 17 mm Hg.Refraction before OS trabeculectomy was OD -7.50/OS -9.00. In postoperative year 24 spherical equivalent phakic refraction was OD -9.00/OS -1.50. Biometry 1 year after resolution of hypotony showed axial lengths OD 24.8, OS 22.6 mm. Cataract surgery was performed in postoperative years 24/26 (OD/OS) with Tecnis DCBOO intraocular lenses of powers 14.0/21.5 diopters; postoperative refractions, 2 years after OS IOP rose to 11-17 mm Hg, were OD +0.25-0.50 x 015/OS -0.75-1.25 x 160 with 20/25 corrected acuity in each eye.Cardiovascular symptoms 24 years after the onset of her glaucoma led to a diagnosis of severe pulmonary hypertension.

Conclusions and importance

This case demonstrates that 2 decades of chronic IOP reduction can reverse myopia (by > 2 mm reduction in axial length) with subsequent refractive stability 2 years after IOP normalization. In addition, the case shows that ocular signs of pulmonary hypertension may precede cardiovascular signs by 2 decades.

Two-year outcomes of anterior versus posterior scleral application of mitomycin C-soaked sponge in trabeculectomy

PURPOSE

To compare the safety and efficacy of two different application methods of mitomycin C (MMC)-soaked sponge in trabeculectomy.

STUDY DESIGN

Retrospective study.

METHODS

We included 71 eyes of 71 patients that had undergone trabeculectomy. In the anterior scleral application group, 36 eyes were treated using the long side of the MMC-soaked sponge placed parallel to the limbus. The efficacy and safety in these eyes were compared with eyes treated with the posterior scleral application group, consisting of 35 eyes treated with the long side of the MMC-soaked sponge placed perpendicular to the limbus. The follow-up period was 2 years. The safety of the procedure, including bleb morphology and complications, was the primary outcome, while the success rate was the secondary outcome.

RESULTS

The cumulative success rate at 2 years postoperatively was 94.4% in the anterior and and 94.3% in the posterior scleral application group (P = 1.000). However, with the posterior scleral application of the MMC-soaked sponge, blebs were more low-lying (P = 0.048), less in extent (P < 0.001), more normally vascularized (P = 0.027) and more posteriorly directed (P < 0.001). Furthermore, the incidence of thin-walled cystic bleb (P = 0.028) and bleb leakage (P = 0.025) was significantly lower in the posterior scleral application group than in the anterior group.

CONCLUSION

Although there were similar success rates, the posterior scleral application of MMC-soaked sponge with trabeculectomy was safer with a better bleb morphology than the anterior scleral application.

Factors Associated with Refractive Prediction Error after Phacotrabeculectomy

PURPOSE

To compare refractive prediction errors between phacotrabeculectomy and phacoemulsification.

METHODS

Refractive prediction error was defined as the difference in spherical equivalent between the predicted value using the Barrett Universal II formula and the actual value obtained at postoperative one month. Forty-eight eyes that had undergone phacotrabeculectomy (19 eyes, open-angle glaucoma; 29 eyes, angle-closure glaucoma) were matched with 48 eyes that had undergone phacoemulsification by age, average keratometry value and axial length (AL), and their prediction errors were compared. The factors associated with prediction errors were analyzed by multivariable regression analyses.

RESULTS

The phacotrabeculectomy group showed a larger absolute prediction error than the phacoemulsification group (0.51 ± 0.37 Diopters vs. 0.38 ± 0.22 Diopters, p = 0.033). Larger absolute prediction error was associated with longer AL (p = 0.010) and higher intraocular pressure (IOP) difference (p = 0.012). Hyperopic shift (prediction error > 0) was associated with shallower preoperative anterior chamber depth (ACD) (p = 0.024) and larger IOP difference (p = 0.031). In the phacotrabeculectomy group, the prediction error was inversely correlated with AL: long eyes showed myopic shift and short eyes hyperopic shift (p = 0.002).

CONCLUSIONS

Surgeons should be aware of the possibility of worse refractive outcomes when planning phacotrabeculectomy, especially in eyes with high preoperative IOP, shallow ACD, and/or extreme AL.

Premium Intraocular Lenses in Glaucoma-A Systematic Review

The incidence of both cataract and glaucoma is increasing globally. With increasing patient expectation and improved technology, premium intraocular lenses (IOLs), including presbyopia-correcting and toric IOLs, are being increasingly implanted today. However, concerns remain regarding the use of premium IOLs, particularly presbyopia-correcting IOLs, in eyes with glaucoma. This systematic review evaluates the use of premium IOLs in glaucoma. A comprehensive search of the MEDLINE database was performed from inception until 1 June 2023. Initial search yielded 1404 records, of which 12 were included in the final review of post-operative outcomes. Studies demonstrated high spectacle independence for distance and good patient satisfaction in glaucomatous eyes, with positive outcomes also in post-operative visual acuity, residual astigmatism, and contrast sensitivity. Considerations in patient selection include anatomical and functional factors, such as the type and severity of glaucomatous visual field defects, glaucoma subtype, presence of ocular surface disease, ocular changes after glaucoma surgery, and the reliability of disease monitoring, all of which may be affected by, or influence, the outcomes of premium IOL implantation in glaucoma patients. Regular reviews on this topic are needed in order to keep up with the rapid advancements in IOL technology and glaucoma surgical treatments.

Early post-operative anterior segment parameters modifications induced by PreserFlo MicroShunt in primary open-angle glaucoma

PURPOSE

The aim this study is to determine anterior chamber parameters variations induced by PreserFlo MicroShunt implantation, in the early post-operative days.

METHODS

This is a prospective observational study on 48 eyes undergoing PreserFlo MicroShunt implantation alone (n = 30) or combined with phacoemulsification (n = 18). Anterior chamber depth (ACD) and volume (ACV), central corneal thickness (CCT) and total corneal astigmatism (TCA) were evaluated pre-operatively, post-operatively at day-1 and at 1 week with the Pentacam tomography.

RESULTS

Intraocular pressure decreased significantly from 20.9 ± 4.0 to 8.0 ± 2.8 mmHg (p < 0.0001) and to 10.8 ± 3.7 mmHg (p = 0.0001) at day-1 and week-1, respectively. TCA varied significantly from baseline (1.5 ± 1.2 D) to both day 1 follow up (2.7 ± 1.9 D, p = 0.0003) and week 1 follow up (2.2 ± 1.6 D, p = 0.02). Nevertheless, only K1 showed a transient flattening at day 1, while K2 value didn't show any statistical variation in the early post-operative period. CCT value rose significantly at day 1 (547 ± 49 vs. 529 ± 32 µm at baseline, p = 0.04), but then returned toward pre-operative values at week 1 (537 ± 39 µm, p = 0.57). In contrast, ACD values changed insignificantly from 3.3 ± 0.9 to 3.7 ± 1.0 mm at day 1 (p = 0.21), and then stabilized at 3.4 ± 0.9 mm (p = 0.82) at week 1 follow up. ACV changed from 150.0 ± 36.2 to 159.5 ± 42.1 mm³ at day 1 (p = 0.58), and successively to 153.9 ± 37.9 mm³ at week 1 follow up (p = 0.96). The subgroup analysis in eyes undergoing standalone PreserFlo implantation didn't show significant changes in both ACD and ACV.

CONCLUSION

PreserFlo implantation minimizes the anterior chamber modifications generated by traditional filtering surgery, inducing low and transient corneal and biometric changes only in the very early postoperative period and insignificant changes to ACD and ACV, label of its safety and minimal invasiveness.

Roles of Toric intraocular Lens implantation on visual acuity and astigmatism in glaucomatous eyes treated with iStent and cataract surgery

Background

To assess the efficacy of toric intraocular lenses (IOLs) in combined cataract and minimally invasive glaucoma surgery (MIGS), visual and refractive outcomes were compared between eyes implanted with non-toric and toric IOLs during iStent triple procedures.

Methods

In this retrospective study, open angle glaucoma eyes with preexisting corneal astigmatism of -1.5 diopter (D) or more and implanted with non-toric (n = 9) or toric (n = 9) IOLs were included. The main outcome measures were the intergroup difference in the uncorrected visual acuity (UCVA) and refractive astigmatism at 3 months postoperatively.

Results

Preoperatively, the logarithm of the minimum angle of resolution (logMAR) UCVAs and refractive astigmatism were equivalent between the groups. Postoperatively, the logMAR UCVA (non-toric, 0.45 ± 0.31; toric, 0.14 ± 0.15; P = 0.021) was significantly better and the refractive astigmatism (non-toric, -2.03 ± 0.63 D; toric, -0.67 ± 0.53 D; P = 0.0014) significantly less in the toric group. The toric group had postoperative improvements in the logMAR UCVA (-0.21, P = 0.020) and refractive astigmatism (+ 1.72 D, P = 0.0039). Vector analyses showed the postoperative centroid magnitude and confidence eclipses of refractive astigmatism was less in the toric group (0.47 D at 173°±0.73D) than the non-toric group (1.10 D at 2°±1.91D). Postoperatively, 78% of eyes in the toric group had 1.0 D or less refractive astigmatism compared with 11% in the non-toric group. Surgically induced astigmatism (non-toric, 0.18 D at 65°; toric, 0.29 D at 137°) did not differ between groups.

Conclusion

Use of toric IOLs is a reasonable option for better visual outcomes when the combined cataract and iStent surgery is performed in glaucomatous eyes with corneal astigmatism.

Refractive Changes after Glaucoma Surgery-A Comparison between Trabeculectomy and XEN Microstent Implantation

Best-corrected visual acuity often decreases temporarily or permanently after trabeculectomy (TE). The purpose of this study was to compare visual acuity and refractive changes after TE or XEN microstent implantation (XEN) in primary open-angle glaucoma (POAG) or pseudoexfoliation glaucoma (PEX) cases naïve to prior glaucoma surgery over a 24-month follow-up period. We analyzed 149 consecutive glaucoma patients who received either TE or XEN because of medically uncontrollable POAG or PEX. Intraocular pressure (IOP), IOP-lowering medication use, subjective and objective refraction and best-corrected visual acuity were evaluated. In addition, surgically induced astigmatism (SIA) was calculated and compared using the vector analysis method described by Jaffe and Clayman. A total of 93 eyes (85 POAG; 8 PEX) were treated with TE and 56 eyes (50 POAG; 6 PEX) with XEN. After 24 months, the mean IOP and number of IOP-lowering medications used decreased significantly after TE (p < 0.01) and XEN (p < 0.01). In the TE group, mean best-corrected visual acuity (BCVA) changed from 0.16 ± 0.26 to 0.23 ± 0.28 logMAR (p < 0.01) after 24 months, while mean BCVA did not change significantly in the XEN group (preoperative: 0.40 ± 0.50 logMAR, postoperative: 0.36 ± 0.49 logMAR; p = 0.28). SIA was almost the same in both groups at the end of the 24-month follow-up period (0.75 ± 0.60 diopters after TE and 0.81 ± 0.56 diopters after XEN; p = 0.57). In addition, there was no significant correlation between SIA and the observed BCVA changes or SIA and IOP reduction 12 or 24 months after TE or XEN. Our results demonstrate that TE and XEN are effective methods for reducing IOP and IOP-lowering medication use. The SIA was nearly similar in both groups. The SIA does not seem responsible for the decreased visual acuity after TE.

Surgically induced astigmatism following single site and twin site phacotrabeculectomy augmented with mitomycin C

PURPOSE

To determine difference in surgically induced astigmatism (SIA), post-operative intraocular pressure (IOP) and axial length (AL) between single site and twin-site phacotrabeculectomy augmented with Mitomycin C (MMC).

DESIGN

Prospective interventional randomised controlled study.

METHODS

In a prospective interventional comparative study, eligible patients were scheduled for phacotrabeculectomy. They were randomised to either group A: single site or group B: twin-site phacotrabeculectomy with MMC 0.2 mg/mL. Axial length was measured by using Zeiss IOL master I, pre-operatively and at 1, 3, 6 and 12 months post-operatively. Corneal topography was performed using Bausch and Lomb Orbscan I pre-operatively and at 3, 6 and 12 months post-operatively to analyse surgically induced astigmatism. Vector analysis was used to analyse the surgically induced astigmatism.

RESULTS

One hundred and eight eyes of which 55 patients in group A, and 53 patients in group B were enroled for vector analysis. The mean preoperative astigmatic vector power was +0.89 ± 0.4 D and +0.97 ± 0.5 D in group A and B respectively. The mean post-operative astigmatic vector power was +0.78 ± 0.4 D in group A and +0.96 ± 0.5 D in group B at the end of 12 months. Corneal topography showed post-operative superior flattening (51.8% at 3 months and 55.4% at 12 months) in group A (P = 0.072) compared to superior steepening (59.6% at 3 months and 61.5% at 12 months) in group B (P = 0.977).

CONCLUSIONS

The two commonly used techniques of combined cataract and glaucoma surgery proved to be efficacious without significant difference in surgical induced astigmatism.

Risk Factors for Corneal Striae in Eyes After Glaucoma Surgery

PRCIS

Eyes with corneal striae had steeper cornea, induced astigmatism, and higher corneal hysteresis (CH), which implies a relationship between striae, corneal shape, and the cornea's resistance to deformation at low intraocular pressures (IOPs).

BACKGROUND

Anterior corneal striae (ACS) are associated with low IOP. However, the clinical significance of ACS is unclear. Here, we aim to evaluate differences in eyes with striae compared with eyes without striae.

METHODS

Adults with ACS (cases) and without ACS (controls) ≥8 weeks after glaucoma surgery with an IOP ≤10 mm Hg were enrolled. Optical coherence tomography and optical biometry were performed. CH, defined as the difference in pressure between corneal indentation and reformation in response to an air jet, was obtained by the ocular response analyzer. Hypotony maculopathy (HM) was defined as optic disc swelling, vascular tortuosity attributed to hypotony, or clinical presence of chorioretinal folds confirmed on OCT.

RESULTS

One hundred sixteen eyes (76 cases, 40 controls) were included. Cases had a lower IOP compared with controls (6.5±2.3 vs. 8.5±1, P<0.0001). A 1 mm Hg increase in CH increased ACS odds [odds ratio (OR)=1.51, P=0.01]. A 1 D increase in the flattest presurgical and postsurgical corneal power increased ACS odds by 1.83 (P=0.01) and 1.41 (P=0.02), respectively. Astigmatism increased in eyes with ACS by 1.11 D (P<0.001). ACS odds were increased with every 1 minute increase in mitomycin-C duration (OR=1.58, P=0.047) and decreased with the use of topical glaucoma medication (OR=0.62, P=0.03). Visual acuity decreased from logarithm of the minimal angle of resolution 0.22 (20/33 Snellen) presurgery to 0.28 (20/38) postsurgery (P=0.008), independent of ACS. HM occurred in 19% of cases (P=0.05). A higher postsurgical CH increased HM odds (OR=1.8, P=0.003). HM predicted a 0.41 mm decrease in axial length (P<0.0001), independent of IOP.

CONCLUSION

ACS were associated with a steeper cornea, induced astigmatism, and higher CH, suggesting a relationship between striae, corneal shape, and the cornea's ability to resist deformations at lower IOP. CH, HM, and axial length shortening were associated independently of IOP.

Refractive Outcomes for Combined Phacoemulsification and Glaucoma Drainage Procedure

INTRODUCTION

To evaluate the refractive outcome of combined cataract extraction and glaucoma drainage device (GDD) surgery.

METHODS

Patients who had undergone combined phacoemulsification with GDD surgery [Baerveldt, Abbott Medical, Abbott Park (IL) or Ahmed valve, New World Medical, Rancho Cucamonga (CA)] between June 2009 and August 2017 were included in the study. The main outcome measure evaluated was whether or not spherical equivalent (SE) between ± 1D from target refraction was achieved at 3-6 months postoperatively.

RESULTS

The final analysis included 42 eyes of 38 patients who underwent combined phacoemulsification and GDD surgery. A refractive outcome of spherical equivalent (SE) between ± 1D of the target refraction was achieved in 30 of 42 eyes (71.43%) at 3-6 months after surgery. Mean preoperative axial length (AL) of eyes with postoperative SE outside ± 1D from target (SD = 0.98, p = 0.003) was noted to be 25.37 ± 0.98 mm (longer mean AL) and that of eyes with SE between ± 1D (SD = 0.89, p = 0.000) was found to be 23.34 ± 0.89 mm (average mean AL). Twelve (29%) eyes were noted to have a mean 0.52D (SD = 0.49; range 0.02-1.49) of corneal astigmatism induced by combined surgery. Age, central corneal thickness, preoperative anterior chamber depth, and pre- and postoperative intraocular pressure did not significantly affect refractive outcomes.

CONCLUSION

Refractive outcomes within 1.00D of the target refraction were achieved in most patients undergoing a combined surgical approach. Longer AL was a risk factor among patients with refractive change > 1.00D from target.

Effect of Trabeculectomy on Mean and Centroid Surgically Induced Astigmatism

This study aimed to investigate the arithmetic mean of surgically induced astigmatism (M-SIA) and the centroid of surgically induced astigmatism (C-SIA) after standard trabeculectomy. We comprised 185 eyes of 143 consecutive patients (mean age ± standard deviation, 67.7 ± 11.6 years) who underwent trabeculectomy and completed at least a 3-month routine follow-up. In all cases, the scleral flap was made at the nasal-superior location. Corneal astigmatism was measured with an automated keratometer. We calculated the M-SIA and the C-SIA using vector analysis and applied the astigmatism double angle plot. The magnitude of corneal astigmatism increased significantly, from 1.17 ± 0.92 D preoperatively to 1.77 ± 1.05 D postoperatively (paired t-test, p < 0.001). The M-SIA was 1.12 ± 0.55 D, and the C-SIA was 0.73 D @64° ± 1.02 D in the right eye group, and the M-SIA was 1.08 ± 0.48 D and the C-SIA was 0.60 D @117° ± 1.03 D in the left eye group. The C-SIA showed an astigmatic shift toward the nasal-superior location of the scleral flap creation. Our results revealed that trabeculectomy induced the SIA in the direction of the scleral flap location and that the C-SIA was much lower than the M-SIA in eyes undergoing trabeculectomy.

[Calculation of intraocular lens power after trabeculectomy]

PURPOSE

To assess biometric changes in eyes after trabeculectomy (TE) and its impact on refractive outcomes of phacoemulsification (PE) in order to determine the corrections for calculation of intraocular lens (IOL) power.

MATERIAL AND METHODS

The study included two groups of patients: the 1^st group consisted of 116 patients who were assessed by optical biometry (IOL-Master 500) for mean biometric values before and after TE; the 2^nd group included 31 patients with history of TE (study subgroup) and 47 individuals without glaucoma (control subgroup) who underwent PE with subsequent comparison of IOL calculation accuracy.

RESULTS

There was significant axial length (AL) shortening in the 1^st group from 23.28±0.97 to 23.19±0.97 mm (p<0.001) 6 months after TE, which positively correlated (r=0.296, p=0.001) with intraocular pressure (IOP) decrease (from 25.4±5.34 to 17.2±4.42 mm Hg, p<0.001). Mean keratometry and anterior chamber depth values did not significantly change after TE. Mean IOL power calculation error after PE in the 2^nd group was -0.05±0.47 D and 0.003±0.62 D for the control and study subgroups, respectively (p=0.697). However, significant impact of preoperative IOP on IOL power calculation error was discovered in the study subgroup (R²=0.526, p<0.001), but not in the control subgroup (R²=0.061, p=0.052). Based on linear regression, the expected IOL power calculation errors depending on the preoperative IOP were determined for patients with history of TE.

CONCLUSION

AL shortening due to decrease in IOP in patients with history of TE leads to IOL power calculation errors. Expected IOL calculation error related to preoperative IOP level was determined, which could help improve refractive outcomes of PE in patients with history of TE.

Comparison of refractive outcomes after combined cataract and glaucoma surgery: trabeculectomy and glaucoma drainage device implantation

PURPOSE

To investigate the refractive outcome of combined cataract surgery and glaucoma drainage device (GDD) implantation compared with trabeculectomy and cataract surgery.

SETTING

Department of Ophthalmology, National University Health System, Singapore.

DESIGN

Retrospective cohort study.

METHODS

206 eyes were enrolled for analysis: 50 had combined cataract surgery and trabeculectomy (trabeculectomy group), 50 had combined cataract surgery and GDD implantation (GDD group), and 106 had cataract surgery alone (control group). Refractive prediction error and absolute prediction error of each glaucoma surgery group were compared with the control group. Subgroup analysis was performed in the following axial length (AL) subgroups: short (<22.5 mm), medium (≥22.5 to <25.5 mm), and long (≥25.5 mm).

RESULTS

In total, 206 eyes were examined. There was no statistically significant difference in the overall refractive prediction error between the GDD (0.00 ± 0.54 diopters [D]) and the control group (0.10 ± 0.53 D, P = .58). There was significant myopic refractive prediction error in the trabeculectomy group (-0.18 ± 0.88 D, P = .020). In eyes with short AL, a greater absolute prediction error was observed in the GDD group (-0.75 ± 0.43 D, P = .039).

CONCLUSIONS

Apart from a significant deviation in short AL eyes, combined cataract surgery and GDD implantation demonstrated no significant postoperative refractive prediction error.

Effect of Toric Intraocular Lens Implantation on Visual Acuity and Astigmatism Status in Eyes Treated With Microhook Ab Interno Trabeculotomy

PRCIS

Use of toric intraocular lenses is a reasonable option for better visual outcomes when a combined minimally invasive glaucoma surgery (MIGS) and cataract surgery is performed in eyes with corneal astigmatism.

PURPOSE

To assess the efficacy of toric intraocular lenses (IOLs) in combined cataract and MIGS, visual and refractive outcomes were compared between eyes implanted with nontoric and toric IOLs during microhook ab interno trabeculotomy triple procedures.

METHODS

Glaucomatous eyes with preexisting corneal astigmatism exceeding -1.5 D implanted with nontoric (n=10) or toric (n=10) IOLs were evaluated retrospectively. The uncorrected visual acuity (UCVA) and refractive astigmatism preoperatively and 3 months postoperatively were compared.

RESULTS

Preoperatively, the groups had similar logarithm of the minimum angle of resolution (logMAR) UCVAs and refractive astigmatism. Postoperatively, the logMAR UCVA (toric, 0.07±0.07; nontoric, 0.33±0.30; P=0.0020) was significantly better and the refractive astigmatism (toric, -0.63±0.56 D; nontoric, -1.53±0.74 D; P=0.0110) significantly less in the toric group. The toric group had postoperative improvements in the logMAR UCVA (-0.58, P=0.0039) and refractive astigmatism (+1.45 D, P=0.0195). Vector analyses showed the postoperative centroid magnitude of refractive astigmatism was less in the toric group (0.23 D at 83 degrees) than the nontoric group (1.03 D at 178 degrees). Postoperatively, 70% of eyes in the toric group had 1.0 D or less refractive astigmatism compared with 10% in the nontoric group. Surgically induced astigmatism (nontoric group, 0.62 D at 10 degrees; toric group, 0.50 D at 113 degrees) and intraocular pressure reduction (22% in both groups) did not differ between groups.

CONCLUSIONS

Better visual outcomes may be achieved with toric IOLs when a combined MIGS/cataract surgery is performed in eyes with corneal astigmatism.

Changes to Corneal Topography and Biometrics after PRESERFLO Microshunt Surgery for Glaucoma

PRECISE

Glaucoma surgery with the PRESERFLO Microshunt shows mild and transient changes in the corneal astigmatism, the corneal elevation and biometrics in the early postoperative period. The posterior corneal elevation tends to be higher in POAG.

PURPOSE

To determine the changes in the corneal keratometry, astigmatism and elevation, refraction, axial length and anterior chamber depth and volume after the implantation of the PRESERFLO Microshunt in patients with primary open angle glaucoma (POAG) in the early postoperative period.

METHODS

Patients diagnosed with primary open angle glaucoma (POAG) who underwent an ab-externo SIBS (poly(styrene-block-isobutylene-block-styrene) microshunt implantation were recruited. The central corneal thickness (CCT), the intraocular pressure (IOP), best corrected visual acuity (BCVA), refraction, biometrics and corneal topography with a Scheimpflug topographer were analyzed preoperatively and 24 hours, 1 week, 1 month and 3 months after surgery.

RESULTS

A total of 30 eyes of 29 patients were included. In 24 eyes the device was implanted as a standalone procedure and in 6 eyes it was combined with cataract surgery. The results were analyzed separately. The IOP decreased from 21.8±5.2 and 16.5±1.5▒mmHg at baseline to 10.9±1.8 and 10.1±1.1mmHg at 3 months in the non-combined and combined groups (P<0.01). The anterior, posterior and total corneal astigmatism (ASA, PSA, TCA) increased in each group 0.4±0.3/ 0.2±1.0 D, 0.08±0.1/ 0.03±0.1 D and 0.4±0.3/ 0.2±0.9 D respectively at 3 months. The anterior and posterior corneal elevation (ACE max, ACE min, PCE max) increased on the first week (P=0.01) with no significant changes at 3 months in the non-combined group. The changes observed in the combined group were not significant. The axial length (AL) decreased 0.13±0.23 and 0.2±0.07▒mm in each group (P=0.01). There was a significant correlation between the IOP and the maximum elevation of the posterior surface of the cornea at the preoperative examination (r=0.93, P= 0.02).

CONCLUSIONS

The PRESERFLO Microshunt implant for glaucoma surgery induces mild and transient changes in corneal astigmatism, axial length and anterior chamber depth in the early post-operative period.

How a dynamic optical system maintains image quality: Self-adjustment of the human eye

The eyeball is continually subjected to forces that cause alterations to its shape and dimensions, as well as to its optical components. Forces that induce accommodation result in an intentional change in focus; others, such as the effect of intraocular pressure fluctuations, are more subtle. Although the mechanical properties of the eyeball and its components permit mediation of such subtle forces, the concomitant optical changes are not detected by the visual system. Optical self-adjustment is postulated as the mechanism that maintains image quality. The purpose of this study was to investigate how self-adjustment occurs by using an optical model of the eyeball and to test the requisite optical and biometric conditions.

Refractive Status in Eyes Implanted with Toric and Nontoric Intraocular Lenses during Combined Cataract Surgery and Microhook Ab Interno Trabeculotomy

Purpose

To compare the refractive status between eyes implanted with toric and nontoric intraocular lenses (IOLs) during combined cataract surgery and microhook ab interno trabeculotomy (μLOT), a minimally invasive glaucoma surgery (MIGS).

Methods

Twenty eyes of 20 patients who had open-angle glaucoma, cataract, and preexisting regular corneal astigmatism exceeding 1.5 diopters (D) and underwent combined μLOT and phacoemulsification were recruited retrospectively. Ten eyes were implanted with a toric IOL and 10 eyes with a nontoric IOL. The primary outcomes were the uncorrected visual acuity (UCVA) and refractive cylinder at 3 months postoperatively.

Results

The mean UCVA of the toric IOL group (logarithm of the minimum angle of resolution (logMAR), 0.23 ± 0.25) was significantly better than that of the nontoric IOL group (logMAR, 0.45 ± 0.26) at 3 months postoperatively (p < 0.05). The mean absolute residual refractive cylinder of the nontoric IOL group (2.25 ± 0.62 D) was significantly greater than that of the toric IOL group (1.30 ± 0.68 D) (p < 0.05). Postoperatively, 60% of eyes in the toric IOL group and 10% in the nontoric IOL group had an absolute refractive astigmatism level of 1.5 D or less. Surgically induced astigmatism (0.77 ± 0.43 D for toric group and 0.60 ± 0.32 D for nontoric group) and IOP reduction (33.9 ± 15.6% for toric group and 29.4 ± 11.7% for nontoric group) were not different between groups.

Conclusions

Use of toric IOL during combined cataract surgery and μLOT is possible and better than not, but physician should prevent their patient of persisting residual astigmatism. The study was registered at https://www.umin.ac.jp/, and the clinical trial accession number is https://clinicaltrials.gov/ct2/show/UMIN000043141.

Surgically induced astigmatism and refractive outcomes following phacotrabeculectomy

Purpose

To objectively evaluate surgically induced astigmatism (SIA) after phacotrabeculectomy using keratometry and topography and to compare the magnitude of SIA and the refractive outcomes of single-site and twin-site phacotrabeculectomies.

Methods

Forty prospective subjects were enrolled in the study and were randomized into single-site and twin-site cohorts. SIA was objectively assessed using keratometry and Orbscan before and at three months after surgery. For both cohorts, the changes in SIA were assessed using power vector analysis compared at the third month after surgery.

Results

Each cohort consisted of 20 eyes. The preoperative parameters and postoperative IOP were comparable and similar, respectively, in both the cohorts (P = 0.1). Majority of the patients in both the cohorts had preoperative against-the-rule (ATR) astigmatism. The median change in SIA at the three-month postoperative visit was similar in both the cohorts, with a small increase in ATR astigmatism. Although the SIA change measured by keratometry in the J0 component was similar in both the groups (P = 0.54), that of J45 was significantly different (P = 0.01). However, the median change in SIA was similar in both the groups for both the J0 (P = 0.52) and J45 components (P = 0.94) when measured by Orbscan. The SIA in both the groups measured with keratometry (P = 0.62) and topography (P = 0.52) were clinically and statistically similar. In both the groups, the refraction was similar at 1 month and 3 months.

Conclusion

The SIA as measured with keratometry and topography was similar in the single-site and twin-site phacotrabeculectomy cohorts at the end of 3-months. The postoperative refraction was stabilized in 1-month in both the groups.

Merits of conjunctival frill incision in reducing trabeculectomy-induced astigmatism and patient discomfort

Purpose

To compare results of a novel "conjunctival frill/smile incision" on surgically induced astigmatism (SIA) and patient discomfort vs conventional trabeculectomy in the initial postoperative period.

Methods

Sixty trabeculectomy cases were subjected to either conjunctival frill incision, performed 1.5-2.0 mm from the limbus (study group) or conventional fornix-based conjunctival flap (control group). Corneal astigmatism and suture-induced discomfort were assessed by keratometry and a self-devised patient questionnaire, respectively.

Results

Both groups generated a "with the rule" SIA, which was 1.77 vs 2.42 at 1 week and reduced to 1.27 vs 1.8 in the study vs control group, after removal of sutures - both scleral flap releasable and conjunctival at 1 month. Patient discomfort score revealed enhanced comfort in 37% of patients (study group) vs 17% (control group) during the early postoperative period. After 1 month of surgery, good comfort was regained in all cases.

Conclusion

This novel suturing technique results in reduced SIA, patient discomfort during the 1st month after trabeculectomy.

Long-term outcomes of prediction error after combined phacoemulsification and trabeculectomy in glaucoma patients

Background

To investigate long-term outcomes of prediction error after phacotrabeculectomy and to determine risk factors that may cause unstable prediction error after phacotrabeculectomy in glaucoma patients.

Methods

A total 120 eyes of 120 patients who had underwent uncomplicated phacotrabeculectomy (combined group) or phacoemulsification (phaco-only group) were included. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) were measured before and after surgery, and anterior segment parameters including anterior chamber depth (ACD), lens vault (LV), and anterior vault (AV) measured using anterior-segment optical coherence tomography were compared between the two groups. The mean absolute error (MAE) at 3, 6, 12, and 24 months postoperatively were compared. Risk factors associated with unstable prediction error (MAE ≥ 0.5) were investigated in the combined group.

Results

In both groups, BCVA was improved and IOP was decreased significantly. MAE at 3, 6, 12, 24 months postoperatively were not significantly different between two groups. The risk factors for unstable prediction error after 12 months of phacotrabeculectomy were old age and LV. Whereas, the only factor predicting unstable prediction error after 24 months of phacotrabeculectomy was LV. The cut-off value of LV for predicting unstable refractive error analyzed by the ROC curve was 0.855 mm.

Conclusions

Phacotrabeculectomy may be an effective treatment with stable long-term outcomes of prediction error similar to phacoemulsification in patients with glaucoma. However, elderly patients or patients with large LV may be predisposed to unstable prediction error after phacotrabeculectomy.

Comparison of intraocular lens power calculation results before and after glaucoma surgery

Aim to compare intraocular lens (IOL) power calculation before and after different types glaucoma procedures. Material and methods.Into the study, 115 patients were included, divided into 3 groups: group 1 patients, in whom sinustrabeculectomy was performed (n= 86); group 2 patients with implanted Ex-PRESS shunt (n= 19), group 3 patients after Ahmed glaucoma valve implantation (n= 10). For each patient before surgery optical biometry (IOL-Master 500) was performed and IOL power calculation using Barrett Universal II Formula (target refraction emmetropia). Baseline data were compared with corresponding examinations results obtained in 6 months after glaucoma procedure, to evaluate its effect on main biometric parameters of the eye and the IOL calculation accuracy. Results.Despite significant changes of optical and anatomic indices, mean values of target refraction before and after glaucoma surgery did not differ significantly: 0.00 0.03 versus 0.03 0.52 D (p= 0.628), 0.00 0.1 versus 0.19 0.61 D (p= 0.173), 0.04 0.08 versus 0.11 0.42 D (p= 0.269) for groups, respectively. However, there was a pronounced trend to the increase of target refraction data scattering. Conclusion.Glaucoma procedures cause changes of biometrical parameters of the eye, which leads to decrease in accuracy of IOL calculation. Consequently, when choosing intraocular lens, it is recommended to use measurement results obtained after glaucoma surgery. Keywords:intraocular lens; IOL power calculation; glaucoma; sinustrabeculectomy; Ex-PRESS shunt; Ahmed glaucoma valve; biometry; phacoemulsification; axial length; anterior chamber depth; keratometry.

Inflammatory-induced astigmatism: acute changes in corneal curvature secondary to marginal keratitis and previous mitomycin-C treatment

A 52-year-old man presented with left eye redness, blurred vision, and photophobia. A history included marginal keratitis and conjunctival squamous cell carcinoma treated with excision and topical mitomycin-C. Examination revealed current marginal keratitis, managed with topical antibiotic and corticosteroid. Regular assessments included high-resolution optical coherence corneal tomography, refraction, and blood tests to exclude other causes of peripheral infiltrate and thinning. Two weeks later, visual acuity (VA) decreased and astigmatism increased. Significant refractive instability with astigmatism increased to 5.25 diopters with a corresponding decrease in VA. After 4 months of topical treatment, the marginal keratitis, astigmatism, and change in VA resolved. To the authors' knowledge, this is the first case report to describe an induced and fluctuating high-magnitude corneal astigmatic change in response to marginal keratitis.

Evaluation of Changes in Refractive Errors Before and After Trabeculectomy and Shunt Surgery

PURPOSE

The aim of the present study was to investigate the change rate of astigmatism and axial, myopia, and hypermetropia in trabeculectomy and shunt surgery.

PATIENTS AND METHODS

In this comparative study, two groups of 16 patients with an average age of 52.4±8.9 and 94.6±6.7 respectively underwent trabeculectomy and shunt surgery. The changes of reactive error were compared before the surgery and 1 week, 1 month, and 3 months after the surgery. Data from the two groups were analyzed via Friedman and Mann-Whitney tests.

RESULTS

Average of intraocular pressure (IOP) before, and 1 week, 1 month, and 3 months after trabeculectomy is 31.31±7.6, 9.8±2.8, 10.5±1.29, 10.9±1.26 (P<0.05) and shunt is 36.06±10.32, 13.5±3.3, 11.68±2.21, 11.18±1.27 (P<0.05). Average astigmatism in trabeculectomy is -1.00±0.59, -6.00±1.9, -2.21±1.18, -1.37±0.62 (P<0.05) and in shunt it is -0.89±0.46, -1.56±1.62, -1.51±1.46, -1.07±0.85 (P>0.05). Percent WRT astigmatism in trabeculectomy is 37.5, 100, 37.5, 31.25 and in shunt it is 43.75, 50, 50, 56.25 and average of spherical equivalence (SE) in trabeculectomy is -0.31±1.49, 1.43±1.94, 0.27±1.74, 0.04±1.46 (P<0.05) and in shunt it is 0.65±1.5, 1.03±2.03, -0.70±1.64, 0.62±1.54 (P<0.05). Astigmatism and axial comparisons between trabeculectomy and shunt with Mann-Whitney test were significant (P<0.05), but SE was not significant (P>0.05).

CONCLUSION

The surgeries induced hypermetropia and reduction with the passing of time but astigmatism amount and percent of with-the-rule astigmatism in trabeculectomy were more than in shunt surgery.

Refractive outcomes of cataract surgery in patients receiving trabeculectomy-a comparative study of combined and sequential approaches

BACKGROUND

Cataract surgery in combination with or after trabeculectomy is often required for improving vision in glaucoma patients. Intraocular pressure (IOP) changes may influence refractive outcomes after cataract surgery. We compared refractive outcomes of the combined and sequential approaches in managing glaucoma and cataract.

METHODS

This retrospective case-control study included 52 patients (57 eyes) who underwent phacotrabeculectomy (combined group) and 39 patients (42 eyes) who underwent phacoemulsification at least three months post-trabeculectomy (sequential group). The IOP and refraction prediction error were compared at three months after cataract surgery. Univariate regression analyses were used to assess risk factors for the postoperative refraction prediction error.

RESULTS

Anti-glaucomatous medications were not administered to either group. The mean postoperative IOP (12.96 vs. 13.80 mmHg; P = .392), refraction prediction error (-0.32 ± 1.53 vs. -0.47 ± 1.14 D, P = .594), mean absolute error (1.02 ± 1.18 vs. 0.8 ± 0.93 D, P = .320), and surgically induced astigmatism (1.85 ± 1.40 vs. 2.16 ± 1.16 D, P = .161) did not differ significantly between the combined and sequential groups. In the sequential group, the refraction prediction error correlated to the IOP change, with a 1-mm Hg rise resulting in a -0.07-diopter shift between the expected and observed refraction (r = -0.380, R² = 0.144, P = .013); no such correlation was observed in the combined group.

CONCLUSION

Both approaches resulted in similar effective IOP control and accurate intraocular lens predictability. The IOP change affected the postoperative refraction prediction error only in the sequential approach.

Learning from the past: Mitomycin C use in trabeculectomy and its application in bleb-forming minimally invasive glaucoma surgery

Trabeculectomy has been performed since the mid-1960s and remains the gold standard for glaucoma surgery. Newer surgical options have evolved, collectively referred to as minimally invasive glaucoma surgeries. Despite producing large intraocular pressure decreases, full-thickness procedures into the subconjunctival space may be limited by fibrosis. Mitomycin C (MMC) and 5-fluorouracil have been in use with trabeculectomy with good evidence of significantly increased success at the cost, however, of an increased risk of complications. Off-label MMC application can be found in almost all clinical trials, including in combination with minimally invasive glaucoma surgeries. We explore current evidence for MMC use in trabeculectomy and how this may differ for minimally invasive glaucoma surgery devices and analyze the range of agents and doses that are used. Although we found that most studies could not show any correlation between MMC dosage and the surgical outcome, the success rates with the Xen® microshunt seemed to be higher when using 20 mcg of MMC than when using 10 mcg. Certain important methodological considerations make this hard to confirm definitively, and other factors such as placement of the device may play a more substantial role. For the PreserFlo® microshunt, preliminary data suggest higher success rates with higher MMC dosage at the cost of higher device-related adverse events and reoperations. Although the ideal dose still needs to be established, it seems very likely that MMC provides significant improvement in outcomes in bleb-forming minimally invasive glaucoma procedures.

Prospective cohort study of risk factors for choroidal detachment after trabeculectomy

PURPOSE

To investigate risk factors for choroidal detachment after trabeculectomy.

METHODS

We prospectively evaluated 97 patients with open-angle glaucoma who underwent primary trabeculectomy to investigate risk factors for choroidal detachment after trabeculectomy. The primary outcome measure was risk factors for the occurrence and severity of choroidal detachment after trabeculectomy. Choroidal detachment severity was quantified as the number of fundus quadrants with choroidal detachment.

RESULTS

Sixteen patients (16.5%) had choroidal detachment. Mean period between surgery and occurrence of choroidal detachment was 7.9 ± 5.7 days. Mean intraocular pressure (IOP) on the first day of choroidal detachment was 6.1 ± 3.0 mm Hg. Multivariable analyses revealed that the exfoliation glaucoma, greater ΔIOP between preoperative and lowest postoperative IOPs, and thicker cornea were associated with choroidal detachment (P = 0.022, P = 0.002, and P = 0.013, respectively). These factors were also associated with the severity of choroidal detachment (exfoliation glaucoma; P = 0.013, greater ΔIOP; P < 0.001, and thicker cornea; P = 0.006).

CONCLUSIONS

Exfoliation glaucoma, more IOP reduction, and thicker cornea are associated with the occurrence and severity of choroidal detachment after trabeculectomy.

Long-term comparison of postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification

PURPOSE

To compare long-term postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification, both with posterior chamber intraocular lens implantation.

SETTING

Department of Ophthalmology, Konyang University, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Seoul, South Korea.

DESIGN

Retrospective comparative study.

METHODS

Postoperative refractive outcomes were compared between patients with cataract and coexisting primary or secondary open-angle glaucoma (OAG) who had phacotrabeculectomy (combined group) and patients with cataract with or without coexisting OAG who had phacoemulsification alone (phaco-only group). The refractive prediction error, mean absolute error, and median absolute error were compared between groups. Subgroup analysis based on preoperative axial length (AL) was performed (medium >22.0 to <24.5 mm; medium-long ≥24.5 to <26.0 mm; long ≥26.0 mm).

RESULTS

The combined group comprised 51 eyes and the phaco-only group, 74 eyes. The mean interval between surgery and refraction measurement was 14.70 months ± 10.80 (SD) (median 13.0 months) and 4.81 ± 4.97 months (median 2.0 months), respectively. Postoperatively, there was no statistically significant between-group difference in the following mean values: refractive prediction error, -0.05 ± 0.64 versus -0.04 ± 0.52 (P = .905); mean absolute error, 0.46 ± 0.44 versus 0.38 ± 0.36 (P = .258); median absolute error, 0.32 (interquartile range [IQR], 0.17, 0.67) versus 0.28 (IQR, 0.13, 0.54) (P = .297). Subgroup analysis also did not show significant differences between the 2 groups (all P > .05).

CONCLUSION

The long-term postoperative refractive outcomes of phacotrabeculectomy and phacoemulsification alone were not significantly different in eyes with OAG, regardless of preoperative AL.

[Refractive shift after glaucoma surgery]

Filtering glaucoma surgery can affect certain biometric features of the eye: it can change the axial length and anterior chamber depth, while redistribution of mechanical tensions in the fibrous tunic can alter the shape of the cornea. Among these changes that affect refraction, reshaping of corneal curvature is the principle one. Contrary to the expectations, and in contrast to changes associated with cataract surgery, glaucoma surgery led to decrease in vertical corneal radius (steepening) and development of the with-the-rule astigmatism. A number of studies helped reveal the features of corneal astigmatism that appears after glaucoma surgery: its power, duration, possibility of horizontal meridian flattening, influence of topical cytostatic drugs and drainage devices, etc. Potential reasons of astigmatism development were suggested: conjunctival incisions and sutures in the limbal area, quantity and strength of flap sutures, intraocular pressure level, shift of fistula edges, tissue contraction after cauterization, etc. The key role in pathogenesis of the refractive shift due to change of corneal curvature may belong to particularities of wound healing in the cornea and sclera: healing in sclera is similar to one of connective tissue - its ultrastructure undergoes aging process followed by change of rigidity. At the same time, the main reason for the development of corneal astigmatism after glaucoma surgery remains unclear.

Prospective Cohort Study on Refractive Changes after Trabeculectomy

We prospectively evaluated refractive changes in the eyes of 97 patients who underwent trabeculectomy at Fukui University Hospital, Fukui, Japan. The primary outcome measure was the refractive change after trabeculectomy. Secondary outcome measures included postoperative complications and prognostic factors for refractive change. We observed a progressive and significant mean refractive myopic shift of −0.80 D at 12 months after surgery. In phakic eyes, the mean myopic refractive shifts progressed significantly by −0.46 D at 3 months after surgery (P=0.003), by −0.52 D at 6 months (P=0.012), and by −1.31 D at 12 months (P < 0.001). In the pseudophakic eyes, we found no significant refraction progression at any of the postsurgery follow-up visits. Our multivariable analyses showed that lens nuclear color grade change was a significant prognostic factor for refractive myopic progression (P < 0.001). Trabeculectomy causes refractive myopic progression in phakic eyes. Nuclear sclerotic cataract progression is associated with refractive myopic shift after trabeculectomy. This trail is registered with UMIN000007813.

Suture Removal After Trabeculectomy With Fornix-based Conjunctival Flap Leads to Faster Visual Recovery but Not Reduced Astigmatism

PRéCIS:: The closing limbal suture after trabeculectomy with a fornix-based conjunctival flap plays no critical role in the development of corneal astigmatism and intraocular pressure (IOP). A standard removal is not recommended.

PURPOSE

To investigate the effect of removal of the conjunctival suture after trabeculectomy with fornix-based conjunctival flap on corneal astigmatism, visual acuity, and IOP.

METHODS

Eighty-seven cases of trabeculectomy with mitomycin C with a fornix-based conjunctival flap performed in the eyes of 82 patients (5 patients underwent bilateral trabeculectomy) were enrolled in a prospective randomized study. All surgeries were conducted by the same surgeon (J.W.) in the Ophthalmology Department of the University Medical Center of Mainz, Germany. All eyes received a corneal-conjunctival, continuous, mattress, interlocked suture for closing the conjunctiva at the limbus. After randomization, in 46 cases the suture was removed 6 weeks postoperatively; in 41 patients, the suture was left in place. All patients were examined preoperatively, and at 6 weeks, 3 months, 6 months, and 12 months after surgery. Astigmatism was measured using objective refraction and corneal topography, IOP and visual acuity were also assessed. Results were compared using a Wilcoxon test or Mann-Whitney U test for single time-points.

RESULTS

During follow-up, no significant differences between the 2 study groups regarding refractive or topographic values were found. Patients in the suture removal group had a significantly higher visual acuity than controls at 3 months, 6 months, and 1 year after surgery. IOP was similar in both groups throughout the study.

CONCLUSIONS

Removal of the conjunctival suture in trabeculectomy with a fornix-based conjunctival flap leads to a faster rehabilitation of visual acuity but does not significantly affect corneal astigmatism or IOP.

Refractive outcomes of cataract surgery in primary congenital glaucoma

AIM

To evaluate refractive outcomes of cataract surgery with intraocular lens (IOL) implantation in operated eyes of primary congenital glaucoma (PCG).

DESIGN

A retrospective case-control study.

METHODS

Patients of PCG who developed cataract following trabeculectomy with trabeculotomy were recruited. Preoperative biometry was recorded and refractive outcomes of the patients in terms of spherical equivalent (SE) and prediction error were noted at 3 and at 12 months following surgery. The refractive outcomes were compared with non-glaucomatous eyes of children in similar age group who underwent lens aspiration with IOL implantation (controls).

RESULTS

The median age of the children with PCG (n = 31) at the time of cataract surgery was 60 months, similar to controls (n = 29); 48 months (p = 0.3). The SE in PCG eyes at 12 months was comparable to controls (p = 0.18). The prediction error (postoperative SE - predicted SE) at 3 months (p = 0.018) and at 12 months (p = 0.03) among PCG eyes was higher and more myopic compared with controls. The range of prediction error at 12 months in PCG eyes was - 8.6 to + 5.8 D (median - 2.0 D), whereas in controls it was - 4.2 to + 6.3 D (median + 0.5 D). For each mmHg intraocular pressure (IOP) increase there was 0.42 mm increase in axial length among PCG eyes and a 0.24 mm increase among controls (p < 0.001).

CONCLUSIONS

After IOL implantation there was a greater prediction error and a greater myopic shift among PCG eyes. Eyes of children with PCG are more prone to refractive surprises as their axial length changes are more sensitive to IOP fluctuation.

Significant hyperopic shift in a patient with extreme myopia following severe hypotonia caused by glaucoma filtering surgery

INTRODUCTION:

To report the case of a high hyperopic refractive shift associated with significant shortening of the ocular axial length following glaucoma filtering surgery.

METHODS:

Case report. Patient's records were consulted retrospectively.

RESULTS:

A 57-year-old woman, highly myopic, with a history of bilateral intraocular refractive surgery in 1998 (phakic lens ZB5M) and bilensectomy in 2011 (phakic intraocular lens extraction plus cataract surgery with pseudophakic intraocular lens implantation), presented with consistently high intraocular pressure. Despite the treatment with different topical antiglaucomatous medications and good compliance, her intraocular pressure values remained consistently above 20 mmHg. In 2016, the patient was submitted for glaucoma filtering surgery and the mini shunt Ex-Press was implanted in both the eyes (3 months between surgeries). On the first postoperative day, the eyes were hypotonic (intraocular pressure of 5 mmHg) and bilateral macular edema was observed. Three days later, the intraocular pressure in both the eyes reached values higher than 6 mmHg (between 6 and 14 mmHg). Five months after the surgery the macular edema resolved and a significant shortening of the axial length and an important hyperopic refractive shift was observed. When comparing the preoperative and postoperative (18 months) measurements, the variation of the axial length was 2.49 mm in the right eye and 2.19 mm in the left eye; the patient refraction (spherical equivalent) shifted 2.50 diopters in the right eye and 1.75 diopters in the left eye.

CONCLUSION:

To the best of our knowledge, we report herein the first documented case of an axial length change of this magnitude after glaucoma filtering surgery.

Stabilization Time of Anterior Segment Parameters After Trabeculectomy Surgery

OBJECTIVES

To investigate the postoperative changes in the anterior segment parameters by Scheimpflug imaging method in patients undergoing trabeculectomy surgery.

METHODS

This prospective study included 38 phakic eyes of 38 patients with primary open-angle glaucoma who underwent trabeculectomy. Anterior chamber angle (ACA), anterior chamber depth (ACD), anterior chamber volume (ACV), and central corneal thickness (CCT) of the eyes were measured by performing Scheimpflug imaging in preoperative (baseline) and postoperative periods (1st week and 1st, 3rd, and 6th months after the surgery).

RESULTS

Significant differences were observed in all the anterior segment parameters during the postoperative period (P<0.001 for ACA, ACD, and CCT; P=0.001 for ACV). Compared with preoperative values, ACA, ACD, and ACV values decreased and CCT value increased in the 1st postoperative week (P<0.001 for all the parameters). Compared with the 1st postoperative-week values, ACA, ACD, and ACV values significantly increased and CCT value significantly decreased in the 1st postoperative month (P=0.002 for ACV; P<0.001 for ACA, ACD, and CCT). However, no significant differences were observed between the baseline and 1st postoperative-month values (P>0.05 for all the parameters). Moreover, the changes in the anterior segment parameters were not statistically significant after the 1st postoperative month.

CONCLUSIONS

Our results showed that the changes in the anterior segment parameters observed in the early postoperative period after trabeculectomy returned to their baseline values after approximately 1 month after the surgery and remained stable thereafter.

Peripapillary Vessel Density Reversal after Trabeculectomy in Glaucoma

Purpose

To evaluate the microvascular changes at the peripapillary area and optic disc in glaucomatous eyes after IOP lowering by trabeculectomy using OCT angiography.

Methods

25 patients with primary open-angle glaucoma (POAG) who underwent trabeculectomy by a single surgeon were evaluated. Using optical coherence tomography angiography, vessel density was evaluated within the whole image, peripapillary, nasal region, and temporal region. Peripapillary vessel density was measured preoperative, 1 week, 1 month, and 3 months postoperatively in POAG patients. Reversal of vessel density was calculated for all analyzed areas.

Results

The intraocular pressure (IOP) decreased from 30.92 ± 6.32 mmHg (range, 18-44) to 12.64 ± 3.35 mmHg (range, 8-22) at 3-month postoperatively. Compared with the preoperative baseline value, whole vessel density, peripapillary vessel density (PvD), and PvD in nasal region and temporal region were significantly increased at 3-month postoperatively. The magnitude of the vessel density reversal was significantly associated with higher preoperative IOP and greater IOP reduction.

Conclusions

A significant increase in the peripapillary vessel density was demonstrated after trabeculectomy using OCT angiography. The reversal of peripapillary vessel density was associated with higher preoperative IOP and greater IOP reduction. Our postoperative results suggest that the ocular perfusion impairment by high intraocular pressure can be improved by IOP reduction, and the reversal of microvasculature may contribute to the rate of glaucoma progression.

Effect of trabeculectomy on ocular higher-order aberrations in patients with open angle glaucoma

OBJECTIVE:

The aim of this study was to evaluate the effect of trabeculectomy on ocular higher-order aberrations following surgery in a group of patients with open angle glaucoma.

METHODS:

In this prospective study, patients with primary open angle glaucoma underwent wavefront aberrometry before trabeculectomy with mitomycin-C. Coma-like, spherical-like, and total ocular higher-order aberrations were measured as root mean square values. The measurements were repeated 1 month and 3 months after the procedure.

RESULTS:

A total of 20 eyes from 20 patients were examined. There was a significant decrease in intraocular pressure following surgery at 1 month and 3 months postoperatively. However, there was no statistically significant change in the spherical equivalent of the eyes. One month after surgery, a significant change in coma-like, spherical-like, and total higher-order aberrations of the eyes was observed. However, the repeated measurements performed 3 months after procedure revealed no significant difference compared to the baseline values.

CONCLUSION:

Ocular higher-order aberrations increased 1 month following trabeculectomy surgery. However, this effect seems to be transient, as the values returned to the preoperative measurement 3 months after the procedure.

Surgically induced astigmatism following trabeculectomy

PURPOSE

Surgically induced astigmatism (SIA) has attracted much interest in recent times because changes in corneal astigmatism can lead to decreased uncorrected visual acuity and patient discomfort. This study aimed to evaluate SIA and to identify factors correlated therewith after trabeculectomy.

METHODS

We retrospectively reviewed medical charts of patients who were treated with trabeculectomy at 120° meridian (superotemporal area on right eye and superonasal area on left eye) by the same surgeon. Preoperative keratometric data were compared with data collected from 2 months to 12 months postoperatively. SIA was evaluated using Naeser's polar value analysis.

RESULTS

Using Naeser's method, ΔKP(120) was calculated as 0.7 ± 0.7 (0.82@104°), which indicates a with-the-rule change. After surgery, the combined mean polar values changed significantly (Hotelling T² = 22.47; p < 0.001). Multivariate analysis of variance indicated that postoperative intraocular pressure and location of surgery were independent factors that were significantly associated with SIA (p = 0.002 and 0.03, respectively).

CONCLUSIONS

Trabeculectomy at the 120° meridian was not astigmatically neutral. In addition, the SIA after trabeculectomy appears to be greater in eyes with low postoperative intraocular pressure and a superonasal surgical wound rather than a superotemporal wound.

Excessive scleral shrinkage, rather than choroidal thickening, is a major contributor to the development of hypotony maculopathy after trabeculectomy

Purpose

We previously reported that eyes with hypotony maculopathy (HM) after trabeculectomy (TLE) exhibited more reduction of axial length (AL) than those without HM, suggesting that inward collapse of the scleral wall may contribute to the development of HM after TLE. However, we did not evaluate change in choroidal thickness (CT), which could influence AL measures. We compared the magnitude and rate of AL and CT changes in eyes with and without HM by simultaneously measuring these parameters before and after TLE.

Methods

We enrolled 77 eyes of 77consecutive patients with glaucoma, who underwent TLE between March 2014 and March 2016. Intraocular pressure (IOP), central corneal thickness, keratometry, AL, and CT were measured pre- and postoperatively, up to 6 months. These biometrics were compared in eyes with and without HM.

Results

The 14 patients who developed HM were significantly younger than those who did not. The eyes with HM exhibited significantly reduced AL (2.8%) compared to those without HM (0.7%). There was no significant difference in CT change between the two groups. The rate of AL reduction was significantly correlated with age, postoperative IOP, and preoperative AL. Post-adjustment logistic regression analysis revealed that eyes with AL reduction rate ≥ 2% had 11.67 higher risk for developing HM (95% confidence interval, 1.28–106.6; P = 0.03).

Conclusions

AL reduction rates ≥ 2% were significantly associated with HM. Excessive reduction in AL, which was seen in eyes with HM, was not an artificial measure resulting from choroidal thickening but rather reflected reductions in the anterior-posterior diameter of the eyeball. Inward collapse of the scleral wall leads to redundancy of the chorioretinal tissue, contributing to the development of HM after TLE.

Short-term change in higher-order aberrations after mitomycin-C-augmented trabeculectomy

PURPOSE

To investigate the changes in ocular higher-order aberrations (HOA) after trabeculectomy using mitomycin-C (MMC).

METHODS

We retrospectively reviewed data for 63 eyes from 63 glaucoma patients who had undergone MMC augmented trabeculectomy. We measured intraocular pressure (IOP), refractive errors, anterior chamber depth (ACD), and HOA before surgery and 1, 2, and 4 weeks postoperatively. The patients were divided into two groups on the basis of preoperative lens status: phakic and pseudophakic group. We used a paired t test to compare preoperative and postoperative HOA values. Regression analysis was used to compare higher-order total (HOT) change and factors including ACD and age.

RESULTS

For entire eye aberrations, coma-like and total HOT were significantly increased postoperatively at 1 week (P = 0.029, P = 0.005, respectively), but not after 2 or 4 weeks in the phakic group and were not significant at any time in the pseudophakic group. Corneal HOA were significantly increased postoperatively after 1, 2 weeks, but not after 4 weeks in the phakic group and were not significant in the pseudophakic group. For internal optics aberrations, HOA were significantly increased postoperatively at 1, 2, and 4 weeks in the phakic group, but were not significant at any time in the pseudophakic group. However, HOT aberration change showed no correlation with age, ACD, IOP change in either group.

CONCLUSION

Following trabeculectomy, HOA changes were significantly increased postoperatively at 1, 2 weeks in the phakic group. Therefore, visual complaint-related HOA changes after trabeculectomy may be more profound in phakic patients.

Comparison of surgically induced astigmatism following different glaucoma operations

Aim

To compare surgically induced astigmatism (SIA) among glaucomatous eyes treated with trabeculectomy (LEC), EX-PRESS^® shunt (EXP), ab externo trabeculotomy (exLOT), or microhook ab interno trabeculotomy (μLOT).

Subjects and methods

Eighty right eyes of 80 subjects who underwent LEC (n=20), EXP (n=20), exLOT (n=20), or μLOT (n=20) were included. The dataset including the best-corrected visual acuity (BCVA), intraocular pressure (IOP), and keratometry recordings preoperatively and 3 months postoperatively was collected by chart review. The means of the vector magnitude, vector meridian, and arithmetic magnitude of the preoperative and postoperative astigmatism and SIA were calculated. The correlations among the SIA magnitude, postoperative BCVA, and IOP were assessed.

Results

The mean astigmatic arithmetic magnitudes did not differ significantly (P=0.0732) preoperatively among the four groups, but the magnitude was significantly (P=0.0002) greater in the LEC group than the other groups postoperatively. The mean SIA vectors were calculated to be 1.01 D at 56°, 0.62 D at 74°, 0.23 D at 112°, and 0.12 D at 97° for the LEC, EXP, exLOT, and μLOT groups, respectively. The mean SIA arithmetic magnitudes were significantly (P<0.0001) greater in the LEC group than the other groups. Three months postoperatively, the SIA magnitude was correlated positively with the logarithm of the minimum angle of resolution (logMAR) BCVA (r=0.3538) and negatively with the IOP (r=−0.3265); the logMAR BCVA was correlated negatively with the IOP (r=−0.3105).

Conclusion

EXP, exLOT, and μLOT induce less corneal astigmatism than LEC in the early postoperative period.

Glaucoma surgery and induced astigmatism: a systematic review

Background

The refractive outcomes of glaucoma surgeries, particularly their effect on astigmatism, are incompletely understood.

Main body

Trabeculectomy is associated with a considerable amount of with-the-rule astigmatic change in the immediate postoperative period. This is followed by a gradual against-the-rule shift. These changes are altered with the use of mitomycin C (MMC). Non-penetrating surgery such as deep sclerectomy is also associated with a similar or smaller degree of induced astigmatism. Minimally invasive glaucoma surgery appears to be astigmatically neutral. There is no clear evidence regarding refractive outcomes of glaucoma drainage device surgery.

Conclusions

Induced astigmatism may account for a reduction in unaided visual acuity in the early postoperative period following a successful trabeculectomy. These changes appear to stabilise at 3 months, and it would be prudent to defer the prescription of new glasses until this time. If sequential cataract surgery is to be performed, toric intraocular lenses can be a useful option for astigmatic correction.

Combined Approach to Phacoemulsification and Trabeculectomy Results in Less Ideal Refractive Outcomes Compared With the Sequential Approach

PURPOSE

To compare the refractive outcomes of combined versus sequential trabeculectomy and then phacoemulsification.

METHODS

We compared eyes that underwent uncomplicated combined phacotrabeculectomy (combined group, 87 eyes), phacoemulsification at least 3 months after trabeculectomy (sequential group, 56 eyes), and phacoemulsification only (control group, 78 eyes) between January 1, 2006 and January 1, 2014. The main outcome measure was refractive prediction error (RPE)-defined as postoperative subjective spherical equivalent refraction minus predicted spherical equivalent refraction.

RESULTS

The study population was predominantly Chinese and the mean age at their cataract surgery was 67.2±9.59 years. Compared with controls, RPE (-0.40±0.70 vs. -0.01±0.50, P<0.001) and mean absolute error (0.62±0.50 vs. 0.39±0.31, P=0.003) were greater for the combined group but not for the sequential group. Proportionately fewer patients in the combined group achieved final subjective refraction within ±0.5D (27.6% vs. 46.2%, P=0.01) compared with controls. Within the sequential group, there were no differences in RPE when the fellow eye axial length was used to predict refractive outcome (P=0.17) or between the group with precataract surgery IOPs of ≤11 mm Hg (-0.28±0.82) and the group with >11 mm Hg (-0.28±0.53, P=0.99). For the sequential group, the use of contact A scan yielded less RPE compared with IOLMaster (P=0.01).

CONCLUSIONS

Combined approach to trabeculectomy and phacoemulsification resulted in greater myopic RPEs that were expectedly greater than those found in the phacoemulsification group.

Combined cataract extraction and trabeculotomy by the internal approach for coexisting cataract and open-angle glaucoma

PURPOSE

To provide efficacy and safety of surgery with Trabectome combined with phacoemulsification in primary open-angle glaucoma.

METHODS

In this interventional case series, 30 consecutive eyes that have had combined phacoemulsification with Trabectome were included. The main outcome measures were change in intraocular pressure (IOP), glaucoma medication use, and the rate of complications.

RESULTS

Mean IOP was 18.25 ± 3.28 mmHg preoperatively which decreased to 13.50 ± 2.53 mmHg at 1 year. (P < 0.05). There was a corresponding drop in glaucoma medications from 2.52 ± 0.60 at baseline to 1.40 ± 0.53 at 12 months (P < 0.01). The preoperative BCVA (Log Mar) was improved from 0.68 ± 0.26 pre-operatively to 0.26 ± 0.19, 0.18 ± 0.13, 0.17 ± 0.13, 0.11 ± 0.12, at 5 days and 2, 6, and 12 months, respectively (P < 0.01). The only frequent complication was transient blood reflux resolving spontaneously within a few days. No vision-threatening complication occurred.

CONCLUSION

Combined phacoemulsification and Trabectome significantly lowered IOP and medication use, with early visual rehabilitation in the majority of patients.

[Comparison of trabeculectomy and canaloplasty : Pressure reducing effect and postoperative interventions/complications]

BACKGROUND

Trabeculectomy (TET) is still the most commonly performed surgical treatment in dealing with primary open angle glaucoma (POAG) worldwide. Canaloplasty (CP) as a nonpenetrating surgical procedure has recently become a new option to efficiently reduce intraocular pressure (IOP).

OBJECTIVES

This study compared both surgical procedures concerning the efficacy in IOP reduction. Furthermore we compared IOP fluctuation, postoperative medication, visual acuity, astigmatism and postoperative interventions and complications.

MATERIALS AND METHODS

Retrospectively studied were 32 eyes after canaloplasty and 31 eyes after trabeculectomy. IOP, IOP fluctuation range, visual acuity, astigmatism and glaucoma medication were recorded preoperatively and after a follow-up of 6 and 12 months. In addition we compared postoperative complications and interventions of both surgical procedures.

RESULTS

The mean IOP after canaloplasty was significantly reduced from 16.0 ± 3.5 mm Hg to 12.5 ± 3.3 mm Hg. Trabeculectomy also achieved a significant IOP reduction from 15.3 ± 3.5 mm Hg to 11.0 ± 2.6 mm Hg. Comparing the two surgical procedures there was no evidence for a significant difference in IOP reduction. Trabeculectomy was able to reduce the number of postoperative glaucoma medication substances better than canaloplasty. There was no difference in postoperative visual acuity or astigmatism. Concerning postoperative complications and interventions canaloplasty treatment was associated with a less severe spectrum of complications.

CONCLUSION

Both procedures provide a safe and efficient IOP reduction. Trabeculectomy is able to achieve an even better IOP reduction without application of additional postoperative medication. Canaloplasty requires shorter inpatient stay, less frequent postoperative checkups and interventions as well as a less severe spectrum of complications.