Longitudinal changes in anterior chamber depth and axial length in Asian subjects after trabeculectomy surgery

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.

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.

Changes in axial length after vitrectomy for rhegmatogenous retinal detachment combined with choroidal detachment

AIM

To report the postoperative axial length (AL) changes in rhegmatogenous retinal detachment combined with choroidal detachment (RRD-CD) patients.

METHODS

The medical records of 97 consecutive patients from January 2015 to December 2018 were reviewed. Patients included were divided into RRD-CD and RRD only groups. All patients had received AL measurements before pars plana vitrectomy (PPV) and before silicone oil removal (SOR). The changes in AL of the two groups were compared. In addition, the potential factors related to AL changes were analyzed.

RESULTS

AL elongation after PPV was 1.01 mm [interquartile range (IQR): 0.37, 1.79; P=0.02] in the RRD-CD group, which was greater than in RRD only group (0.15 mm, IQR: 0.04, 0.41; P<0.001). AL increased 0.06 mm per 1 mm Hg intraocular pressure changes in the RRD-CD group (R ²=0.11, P=0.03). RRD-CD patient was 11.42 times (3.54-46.80) more likely to experience post-PPV AL elongation of more than 1 mm [P<0.001, Akaike information criterion (AIC)=92.33, area under the curve (AUC)=0.839].

CONCLUSION

RRD-CD patients are very likely to have a postoperative elongation of AL. The primary intraoclular lens implantation using presurgery AL data may cause a significant refractive error in RRD-CD patients who underwent PPV.

Lowering Intraocular Pressure: A Potential Approach for Controlling High Myopia Progression

High myopia is among the most common causes of vision impairment, and it is mainly characterized by abnormal elongation of the axial length, leading to pathologic changes in the ocular structures. Owing to the close relationship between high myopia and glaucoma, the association between intraocular pressure (IOP) and high myopia progression has garnered attention. However, whether lowering IOP can retard the progression of high myopia is unclear. On reviewing previous studies, we suggest that lowering IOP plays a role in progressive axial length elongation in high myopia, particularly in pathologic myopia, wherein the sclera is more remodeled. Based on the responses of the ocular layers, we further proposed the potential mechanisms. For the sclera, lowering the IOP could inhibit the activation of scleral fibroblasts and then reduce scleral remodeling, and a decrease in the scleral distending force would retard the ocular expansion like a balloon. For the choroid, lowering IOP results in an increase in choroidal blood perfusion, thereby reducing scleral hypoxia and slowing down scleral remodeling. The final effect of these pathways is slowing axial elongation and the development of scleral staphyloma. Further animal and clinical studies regarding high myopia with varied degree of IOP and the changes of choroid and sclera during IOP fluctuation in high myopia are needed to verify the role of IOP in the pathogenesis and progression of high myopia. It is hoped that this may lead to the development of a prospective treatment option to prevent and control high myopia progression.

Accuracy of intraocular lens power calculation in primary angle-closure disease: comparison of 7 formulas

PURPOSE

To assess the accuracy of intraocular lens power calculation formulas Barrett Universal II (BUII), Hill-Radial Basis Function (RBF) 3.0, Kane, Ladas Super Formula (LSF), Haigis, Hoffer Q, and SRK/T in primary angle-closure disease (PACD).

METHODS

A total of 129 PACD eyes were enrolled. Prediction refraction was calculated for each formula and compared with actual refraction. Accuracy was determined by formula performance index (FPI), median absolute error (MedAE) and percentage of eyes with a prediction error (PE) within ± 0.50D. Subgroup analysis was performed according to axial length (AL).

RESULTS

Overall, FPI was ranked as follows: Kane (0.067), RBF 3.0 (0.064), Haigis (0.062), SRK/T (0.060), BUII (0.058), Hoffer Q (0.055), and LSF (0.049). Kane got the highest (71.3%) percentage of eyes with PE within ± 0.50 D. In medium AL eyes (22 mm < AL ≤ 25 mm), FPI ranked the same as in total group. MedAEs were equal across all formulas (P = 0.121). In short eyes (AL ≤ 22 mm), FPI was Kane (0.055), RBF 3.0 (0.050), SRK/T (0.050), Haigis (0.049), BUII (0.047), Hoffer Q (0.045), and LSF (0.033). MedAEs were significantly different across all formulas (P = 0.033). Haigis showed the lowest MedAE (0.35 D), Haigis and Kane got the highest percentage (63.6%) of eyes with PE within ± 0.50 D.

CONCLUSION

Kane outperformed in total PACD eyes; RBF 3.0, Haigis, and SRK/T achieved satisfying performance. When dealing with PACD eyes shorter than 22 mm, Kane achieved the best accuracy. RBF 3.0, SRK/T, Haigis, and BUII achieved comparable outcomes. No formula showed superiority over others for medium AL PACD eyes.

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.

Intraocular Pressure Decrease Does Not Affect Blood Flow Rate of Ophthalmic Artery in Ocular Hypertension

Purpose

To investigate if decrease of IOP affects the volumetric blood flow rate in the ophthalmic artery (OA) in patients with previously untreated ocular hypertension.

Methods

Subjects with untreated ocular hypertension (n = 30; mean age 67 ± 8 years; 14 females) underwent ophthalmologic examination and a 3-Tesla magnetic resonance imaging investigation. The magnetic resonance imaging included three-dimensional high-resolution phase-contrast magnetic resonance imaging to measure the OA blood flow rate. The subjects received latanoprost once daily in the eye with higher pressure, the untreated eye served as control. The same measurements were repeated approximately 1 week later.

Results

The mean OA blood flow rate before and after treatment was 12.4 ± 4.4 and 12.4 ± 4.6 mL/min in the treated eye (mean ± SD; P = 0.92) and 13.5 ± 5.2 and 13.4 ± 4.1 mL/min in the control eye (P = 0.92). There was no significant difference between the treated and control eye regarding blood flow rate before (P = 0.13) or after treatment (P = 0.18), or change in blood flow rate after treatment (0.1 ± 3.1 vs. -0.1 ± 4.0 mL/min, P = 0.84). Latanoprost decreased the IOP by 7.2 ± 3.1 mm Hg in the treated eye (P < 0.01).

Conclusions

The results indicate that a significant lowering of IOP does not affect the blood flow rate of the OA in ocular hypertension subjects. The ability to maintain blood supply to the eye independent of the IOP could be a protective mechanism in preserving vision in subjects with ocular hypertension.

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.

Ocular biometric changes after Ahmed glaucoma valve implantation

PURPOSE

To investigate the ocular biometric changes after uneventful Ahmed glaucoma valve implantation.

METHODS

Patients with refractory glaucoma who were candidate for Ahmed valve surgery were prospectively included in this study. Patients with a history of any kinds of corneal surgery were excluded. Refractive status, intraocular pressure, axial length, anterior chamber parameters including anterior and posterior mean keratometry, central corneal thicknesses, and anterior chamber depth, anterior chamber volume, and anterior chamber angle were evaluated at baseline and 1 and 3 months after surgery.

RESULTS

A total of 20 eyes from 20 patients were included. Mean intraocular pressure at baseline was 33.4 ± 12.3 mm Hg that significantly decreased to 14.6 ± 6.2 mm Hg at 1 month and 13.5 ± 4.3 mm Hg at 3 months after Ahmed glaucoma valve implantation (p < 0.001). Mean number of medications was 3.6 ± 1.3 at baseline which significantly decreased to 1.0 ± 1.3 at 3 months after Ahmed glaucoma valve implantation (p < 0.001). Axial length decreased significantly from 23.69 ± 1.95 to 23.47 ± 1.91 mm (p < 0.001) at month 3. There were no significant changes in other parameters such as mean spherical equivalent, anterior chamber volume, anterior chamber angle, anterior chamber depth, and keratometry at the end of month 3 after surgery (p > 0.05 in all).

CONCLUSION

Ahmed glaucoma valve implantation had a significant effect on axial length at 3 months after surgery but its effect on keratometry and other anterior chamber parameters was not significant.

Pulse Waveform Analysis of the Ocular Blood Flow Using Laser Speckle Flowgraphy before and after Glaucoma Treatment

Although reduction in intraocular pressure (IOP) is the principle of glaucoma treatment, impaired ocular blood flow is believed to play a role in the progression of glaucoma. This study evaluated the effect of glaucoma treatment on pulse waveforms for optic nerve head (ONH) microcirculation in patients with glaucoma. Fifty-one subjects were included on the basis of the glaucoma treatment administered, which involved instillation of prostaglandin (PG) analogs (PG group; n = 28) or trabeculectomy (trabeculectomy group; n = 23). ONH blood flow, represented by the mean blur rate (MBR_T) and pulse waveforms, was measured using laser speckle flowgraphy before and 1 and 3 months after treatment. Three months after treatment, IOP exhibited a significant decrease (p < 0.05). Although there was no significant change in MBR_T after treatment, the acceleration time index (ATI) significantly decreased (p=0.034) in the PG group. In the trabeculectomy group, there was no significant change in the MBR_T after treatment, while fluctuation (p=0.019) and blowout score (BOS) (p=0.036) exhibited significant decrease and increase, respectively. Multiple regression analysis showed that mean deviation was significantly associated with the rate of change in the BOS (p=0.013), age was a significant contributing factor for the rate of change in fluctuation in the trabeculectomy group, reflection was significantly associated with the ATI (p=0.037) in the in the PG group. Both glaucoma treatments can change the pulse waveforms, with MBR_T remaining unchanged, and IOP reduction owing to the treatment may contribute to stable blood flow in the tissue area of the ONH. As impaired ocular blood flow plays a role in the progression of glaucomatous damage, it would be beneficial if glaucoma treatment could improve the stability of ONH microcirculation.

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.

Objective documentation of anterior chamber depth following trabeculectomy and its correlation with intraocular pressure and bleb functionality

The purpose of this study was to objectively evaluate the anterior chamber depth (ACD) after trabeculectomy and to correlate its variations with the intraocular pressure (IOP) and bleb functionality.Fifty eyes (46 patients) were included in this prospective study. ACD was documented with the use of a non-contact optical device (IOL Master-Carl Zeiss Meditec) and IOP was measured with the Goldmann applanation tonometer.Ophthalmological examination, IOP, and ACD measurements were performed before surgery, the day after and weekly thereafter.Linear regression Analysis between the 2 variables was performed and correlation coefficients were estimated. A 2-tailed t test was used and a P value < .05 was considered as statistically significant.Correlation coefficients between ACD and IOP, during the follow-up period, resulted in a moderate to strong positive relationship (r = 0.2-0.7), which since the 1st week resulted statistically significant at 5%.Twenty seven eyes (54%) needed at least 1 needling procedure. Considering each group separately, until the 3rd post-op week, the correlation coefficients in the needling group resulted higher than those in the non-needling group. Furthermore, in the needling group, the relationship between ACD and IOP, for the 1st, 2nd, 3, and 4th week was statistically significant at 5%.The objective documentation of the ACD in the early post-trabeculectomy period presents a moderate to strong positive correlation with the IOP.Furthermore, the brisk deepening of the ACD during the first 2 to 4 post-operative weeks is strongly correlated with the increase of the IOP and early signs of bleb encapsulation.

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.

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.

Changes in macular thickness after trabeculectomy with or without adjunctive 5-fluorouracil

Conflict of interest.

None of the authors have any conflict of interest to declare, financial or otherwise. No financial or other support was received for the study.

Background.

The aim of the study was to assess changes in macular thickness after trabeculectomy in respect to the use of 5-fluorouracil (5-FU) as well as to analyse possible associations between the postoperative changes in macular thickness and intraocular pressure (IOP).

Materials and methods.

The prospective observational study included 106 eyes (100 patients) with glaucoma who underwent trabeculectomy with or without 5-FU. Subsequently 5-FU needling was performed if failure of the filtrating bleb occurred. Macular thickness and the IOP were evaluated before, one week, and six months after the surgery. The mean and sectoral macular thickness was assessed using spectral domain optical coherence tomography.

Results.

The mean (±SD) IOP reduced from 27.71 (±6.88) mmHg at baseline to 18.3 (±8.1) mmHg one week (p < 0.001) and 15.1 (±7.6) mmHg six months (p < 0.001) after trabeculectomy. One week postoperatively, the mean macular thickness increased from 285.19 (±15.98) μm to 288.9 (±16.31) μm (p < 0.001); macular thickening was significant in all subfields (p < 0.001) and correlated positively with IOP reduction (rho = 0.312, p = 0.001 for central subfield). After six months, macula remained thicker only at the central and inner nasal subfields (p < 0.05). The changes in macular thickness were not affected by the use of 5-fluorouracil.

Conclusions.

Trabeculectomy may induce a slight macular thickening which is more pronounced in the early postoperative period. The IOP reduction plays an important role in this process and is associated with thicker postoperative macula. However, the use of adjunctive 5-FU has no influence on macular thickness after glaucoma surgery despite its potential hypotonic, inflammatory and cytotoxic effects.

Intraocular Pressure, Axial Length, and Refractive Changes after Phacoemulsification and Trabeculectomy for Open-Angle Glaucoma

PURPOSE

To compare changes in intraocular pressure (IOP), axial eye length (AEL), and refractive outcome in primary open-angle glaucoma patients undergoing cataract surgery and trabeculectomy in dependence of the sequence of surgeries.

MATERIALS AND METHODS

We retrospectively analysed 48 eyes. The changes in refraction, intraocular pressure, and axial eye length were analysed after surgery. In group A (21 subjects), phacoemulsification was performed before trabeculectomy, and in group B (27 subjects), trabeculectomy was performed before phacoemulsification with a minimum time span between interventions of 6 months.

RESULTS

The reduction in IOP and the decrease in AEL after trabeculectomy were significant after 6 and 12 months postsurgery (p < 0.001 each). The decrease in AEL was 0.42 ± 0.11% at 6 months after surgery and 0.40 ± 0.13% after 12 months from surgery; this decrease in AEL was comparable between the groups. The refractive outcome was significantly different between the groups (group A: 0.35 ± 0.75 dpt, group B: -0.05 ± 0.36 dpt, p = 0.018); in group A, trabeculectomy caused a hyperopic shift of 0.34 ± 0.44 dpt (p = 0.002) at 12 months postsurgery.

CONCLUSION

IOP reduction after trabeculectomy causes AEL shortening. The effect on refractive outcome depends on the sequence of surgeries. Better refractive outcome is achieved if phacoemulsification is performed after trabeculectomy.

Changes in the Choroidal Thickness and Axial Length Upon Mannitol Infusion in Patients With Asymmetric Intraocular Pressure

BACKGROUND/AIMS

To evaluate the changes in the choroidal thickness (CT) and axial length (AL) upon systemic mannitol infusion in glaucoma patients with asymmetric intraocular pressure (IOP).

MATERIALS AND METHODS

Forty glaucoma patients with asymmetric IOP, with the IOP of 1 eye ≥40 mm Hg and the fellow eye <25 mm Hg, were administered 150 mL of a 20% mannitol infusion to reduce the IOP. The CT and AL were measured before and an hour after the infusion. The relationship between the IOP reduction and the changes in the CT and AL were investigated.

RESULTS

The mean decrease in the IOP was -14.23 mm Hg (32.15%) and -4.13 mm Hg (21.40%) in the eyes with higher IOP and their fellow eyes, respectively. The mean changes in the subfoveal CT were 19.28 µm (9.20%; P<0.001) and 2.60 µm (1.93%; P=0.452) in the eyes with higher IOP and their fellow eyes, respectively. The mean changes in the AL were -0.10 µm (0.42%; P<0.001) and -0.33 mm (0.14%; P=0.008) in the eyes with higher IOP and their fellow eyes, respectively. Stepwise analysis revealed that the percent IOP change is the most influential factor on the percent change of the subfoveal CT (P<0.0001; R=0.3).

CONCLUSIONS

These results suggest that large IOP changes upon mannitol infusion cause the shortening of the AL in both the eyes and the thickening of the choroid only in the eyes with a higher IOP.

Ocular Biometric Changes after Trabeculectomy

This review article aimed to evaluate ocular biometric changes after trabeculectomy. The PubMed database was searched using the keywords "axial length" (AL), "anterior chamber depth" (ACD), "corneal astigmatism," "corneal topography" and "trabeculectomy." The extracted studies were categorized based on the evaluated parameters and the biometry method (contact and non-contact). Comparable studies with respect to their sample size were combined for statistical analysis. Twenty-five studies including 690 individuals which met the inclusion criteria were selected. After trabeculectomy, a significant and persistent AL reduction, with a range of 0.1-0.19 and 0.1-0.9 mm measured with contact and non-contact methods, respectively, was observed. With respect to topographic changes, 0.38-1.4 diopters (D) with-the-rule (WTR) astigmatism was induced postoperatively. All studies revealed ACD reduction immediately after surgery, which gradually deepened and approximated its preoperative levels on day 14. ACD reduction was not significant after that period in the majority of cases. In conclusion, changes in ACD is of small amount and of short period, thus it can be ignored; however, reported changes in AL and keratometry are of sufficient magnitude and can affect the refractive prediction of combined cataract surgery and trabeculectomy.

Changes in choroidal thickness after intraocular pressure reduction following trabeculectomy

PURPOSE

To evaluate the changes of peripapillary and subfoveal choroidal thickness (CT) after trabeculectomy.

METHODS

Prospective longitudinal study included 37 eyes with open-angle glaucoma. The subfoveal and peripapillary CT was measured using enhanced depth imaging spectral domain optical coherence tomography before trabeculectomy and 1 week, 3 and 6 months postoperatively. The associations between changes in the CT, intraocular pressure (IOP) and axial length were analysed.

RESULTS

The medium subfoveal CT (IQR) increased from 182 (97) μm at baseline to 267 (107) μm 1 week, 213 (97) μm 3 months and 207 (91) μm 6 months postoperatively (p < 0.001). The peripapillary CT increased in all four quadrants at all follow-ups (p < 0.05). The subfoveal and peripapillary choroidal thickening correlated with the magnitude of IOP reduction (p < 0.05) and axial length shortening (p < 0.01) during whole follow-up period. There was a peripapillary CT increase of 2.9 μm per mmHg of IOP reduction (p < 0.001, CI 1.5-4.4) and 4.8 μm per mm of baseline axial length (p = 0.049, CI 0.03-9.6) 1 week postoperatively after adjustment for baseline IOP. Six months postoperatively, the decrease in axial length was the only factor associated with peripapillary choroidal thickening (p = 0.031; regression coefficient: 73.29 μm/mm, CI 7.1-139.5).

CONCLUSION

Intraocular pressure (IOP) reduction after trabeculectomy caused the increase in subfoveal and peripapillary CT for at least 6 months postoperatively correlating with greater IOP reduction and axial length shortening. In the long term, the decrease in axial eye length, but not IOP, was the only factor to be associated with peripapillary choroidal thickening.

Effect of trabeculectomy on the accuracy of intraocular lens calculations in patients with open-angle glaucoma

BACKGROUND

The objective of the study is to examine the effect of trabeculectomy on intraocular lens power calculations in patients with open-angle glaucoma (OAG) undergoing cataract surgery.

DESIGN

The design is retrospective data analysis.

PARTICIPANTS

There are a total of 55 eyes of 55 patients with OAG who had a cataract surgery alone or in combination with trabeculectomy.

METHODS

We classified OAG subjects into the following groups based on surgical history: only cataract surgery (OC group), cataract surgery after prior trabeculectomy (CAT group), and cataract surgery performed in combination with trabeculectomy (CCT group).

MAIN OUTCOME MEASURES

Differences between actual and predicted postoperative refractive error.

RESULTS

Mean error (ME, difference between postoperative and predicted SE) in the CCT group was significantly lower (towards myopia) than that of the OC group (P = 0.008). Additionally, mean absolute error (MAE, absolute value of ME) in the CAT group was significantly greater than in the OC group (P = 0.006). Using linear mixed models, the ME calculated with the SRK II formula was more accurate than the ME predicted by the SRK T formula in the CAT (P = 0.032) and CCT (P = 0.035) groups.

CONCLUSIONS

The intraocular lens power prediction accuracy was lower in the CAT and CCT groups than in the OC group. The prediction error was greater in the CAT group than in the OC group, and the direction of the prediction error tended to be towards myopia in the CCT group. The SRK II formula may be more accurate in predicting residual refractive error in the CAT and CCT groups.

Biometric Changes After Trabeculectomy with Contact and Non-contact Biometry

PURPOSE

To compare biometric changes measured with contact and noncontact methods after mitomycin-C-augmented trabeculectomy.

METHODS

In this prospective study, 31 eyes from 31 glaucoma patients scheduled for primary trabeculectomy were enrolled. Biometric parameters including axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) were measured using contact ultrasound biometry (UD-6000 Ultrasonic A/B scanner biometer; Tomey Corporation, Nagoya, Japan) and a noncontact optical biometry device (Lenstar; Haag-Streit AG, Koeniz, Switzerland). Measurements were taken the day before trabeculectomy and then compared with measurements obtained 3 and 6 months after surgery.

RESULTS

The AL and ACD were significantly decreased at 3 and 6 months compared with baseline values taken with each biometry method. There was a significant increase in LT measured by the Lenstar device at the 3- and 6-month follow-up. At both the 3- and 6-month follow-up, the mean AL measurement reduction with the Lenstar device was significantly lower than that of the A-scan ultrasound measurements. The mean ACD changes between the two devices were not significantly different.

CONCLUSIONS

There is a small but significant decrease in the AL and ACD after trabeculectomy as measured with both the contact and noncontact methods. The amount of AL reduction measured is significantly smaller using the noncontact method, making it the preferable method for intraocular lens power calculation for patients who need cataract surgery combined with or after trabeculectomy. The LT measured by the Lenstar device increased significantly after the operation, which can be an early sign of the progression of cataractous changes after trabeculectomy.

One Year of Glaucoma Research in Review: 2012 to 2013

PURPOSE

The objective of this study was to provide the practicing clinical ophthalmologist with an update of pertinent glaucoma literature published from 2012 to 2013.

DESIGN

Literature review.

METHODS

The authors conducted a 1-year (July 1, 2012, to September 30, 2013) English-language glaucoma literature search on PubMed using the following terms: glaucoma, automated perimetry, optic nerve imaging, optical coherence tomography, glaucoma structure and function, intraocular pressure, central corneal thickness, glaucoma medical therapy, neuroprotection, glaucoma laser treatment, secondary glaucoma, glaucoma surgery, and miscellaneous topics in glaucoma.

RESULTS

Of 2659 articles on glaucoma published during our time frame, this review selected original and review articles that reflect novel aspects and updates in the field of glaucoma, while excluding letters to the editor, unpublished works, and abstracts. Preference was given to human research.

CONCLUSIONS

This review focuses on literature that is applicable to ophthalmologists in practice and also highlights studies that may enhance the diagnosis and management of glaucoma.