Effect of cataract extraction and intraocular lens implantation on nerve fibre layer thickness measurements by scanning laser polarimeter (GDx) in glaucoma patients

Meta-Analysis of the Comprehensive Efficacy of Intraocular Lens Implantation in Glaucoma Patients

This study is aimed at investigating the efficacy of intraocular lens (IOL) implantation in patients suffering from glaucoma through meta-analysis of the previously published research. For this purpose, different literature databases were searched for identification of clinical studies published between January 2000 and January 2022 on evaluating IOL's efficacy in treating glaucoma. RevMan 5.3 was used to conduct a meta-analysis of the pertinent data. The central anterior chamber depth (ACD), corneal endothelial cell counts, best-corrected visual acuity (BCVA), intraocular pressure (IOP), anti-glaucoma medications (AGM), and axial length (AL) changes were compared, and the incidence of postoperative complications was thoroughly evaluated. The Cochran chi-square test was used to examine the heterogeneity of the evaluation results. According to the inclusion and exclusion criteria, 20 studies included 948 glaucomatous eyes. IOP was significantly lower than before treatment (MD = 8.64, 95 CI: 5.75-11.53; Z = 5.86, P < 0.0001), while ACD increased significantly (MD = -1.38, 95 percent CI: -1.74-1.02; Z = 7.49, P < 0.0001). The corneal endothelial cell counts were homogeneous (MD = 225.08, 95% CI: -64.17 to -514.33; Z = 1.53, P = 0.20). AGM utilisation decreased (MD = 1.43, 95% CI: 0.752.12, Z = 4.09, P < 0.0001). AL decreased significantly (MD = 0.31; 95% CI: 0.09-0.54; Z = 2.71; P = 0.007). The incidence of complications remained insignificant after IOL treatment (OR = 1.05, 95% CI: 0.42 to 2.60; Z = 0.10, P = 0.92; P = 0.92). These findings indicate that IOL treatment can significantly reduce intraocular pressure, glaucoma drug use, and aqueous level (AL) in glaucoma patients while increasing the depth of the central anterior chamber. This study offers a theoretical foundation for selecting glaucoma treatment methods.

Correlation in retinal nerve fibre layer thickness in uveitis and healthy eyes using scanning laser polarimetry and optical coherence tomography

PURPOSE

To evaluate the correlation of retinal nerve fibre layer (RNFL) thickness measured using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP) in uveitic eyes compared with healthy eyes.

METHODS

A descriptive, observational, prospective, consecutive, cross-sectional, controlled, monocentre case series was conducted from May to October 2015. Clinical characteristics, best-corrected visual acuity, intraocular pressure, RNFL thickness measurement with SD-OCT and SLP using GDx variable corneal compensation (GDx VCC) were performed for each patient. An evaluation of anterior chamber inflammation with laser flare-cell meter was also carried out. Correlations between SD-OCT and GDx VCC RNFL measurement were evaluated by linear regression analysis.

RESULTS

Fifty-four patients were included and divided into two groups: 50 healthy eyes in 29 patients and 42 uveitic eyes in 25 patients. The mean RNFL thickness was 98.08(±8.42) and 113.21(±20.53) μm in the healthy group and the uveitic group, respectively, when measured with SD-OCT (p<0.001); and 56.43(±5.24) and 58.77(±6.67) μm, respectively, when measured with GDx VCC (p=0.078). There was a strong correlation between total average RNFL thickness measured using SD-OCT and GDX (r=0.48, p<0.001) in healthy eyes but there was no correlation in the uveitic eyes (r=0.2, p=0.19).

CONCLUSIONS

RNFL thickness was significantly greater when measured using SD-OCT in active uveitis as compared with GDx. There was no correlation between the RNFL thickness measurements obtained using the two techniques in uveitic eyes. The discrepancies between the results suggest that for these patients both techniques should be used in conjunction to obtain an accurate measurement of RNFL.

TRIAL REGISTRATION NUMBER

IRB 00008855 Société Française d'Ophtalmologie IRB#1.

Scanning laser polarimetry in glaucoma

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.

Associations with retinal nerve fiber layer measures in the EPIC-Norfolk Eye Study

PURPOSE

To describe GDxVCC retinal nerve fiber layer (RNFL) measures and associations in a predominantly white British population.

METHODS

The EPIC-Norfolk Eye Study is nested within a large multicenter cohort study, the European Prospective Investigation of Cancer. RNFL measurements were taken using the GDxVCC. Generalized estimating equation models were used to assess associations of RNFL measures with age, sex, body mass index (BMI), height, blood pressure, social class, education level, alcohol intake, smoking status, axial length, intraocular pressure, and lens status. Models were linearly adjusted for typical scan score to handle scans with atypical retardation.

RESULTS

There were complete data from 11,030 eyes of 6309 participants with mean age 68 years (48-90 years). Older age (-1.53 μm/decade [95% confidence interval {CI} -1.73, -1.33], P < 0.001), male sex (-0.44 μm [95% CI -0.04, -0.84], P = 0.031), shorter axial length (-0.15 μm/mm [95% CI -0.02, -0.28], P = 0.024), and pseudophakia (-0.49 μm [95% CI -0.94, -0.04], P = 0.033) were associated with thinner RNFL after adjustment for possible confounders. Higher BMI was associated with a thinner RNFL in men only (-0.30 μm/5 kg/m(2) [95% CI -0.58, -0.02], P = 0.039).

CONCLUSIONS

This analysis of associations with RNFL thickness in a largely healthy population may provide insight into the determinants of glaucoma, suggesting higher risk in those who are older, in men, and in men with a higher BMI.

Rates of retinal nerve fibre layer thickness change in glaucoma patients and control subjects

PURPOSE

To examine the rates of retinal nerve fibre layer thickness (RNFLT) change in glaucoma patients and healthy, age-similar control subjects with three techniques: scanning laser polarimetry with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and time-domain optical coherence tomography (OCT).

METHODS

Sixty-one patients and thirty-three controls were examined with each technique and with standard automated perimetry (SAP) every 6 months. Rates of global RNFLT change and SAP mean deviation (MD) change were estimated with linear mixed-effects models.

RESULTS

The median (interquartile range) baseline age was 64.4 (58.2, 71.0) years for patients and 62.4 (56.3, 70.1) years for controls (P=0.56). There was a median of seven examinations over 3.1 years for patients and six examinations in 3.0 years for controls. Baseline visual field MD and RNFLT for all imaging modalities were significantly lower (P<0.01) in patients compared with controls. Rates of RNFLT change were not significantly different between patients and controls (P≥0.19). Mean rates of VCC-measured RNFLT change were -0.18 and -0.37 μm per year in patients and controls, whereas the respective figures for ECC and OCT were -0.13 and -0.31 μm per year, and 0.04 and 0.61 μm per year. Mean rates of MD change were -0.20 and 0.03 dB per year in patients and controls, respectively (P=0.01).

CONCLUSION

Rates of RNFLT change in glaucoma patients were not statistically different from control subjects for any modality. A significantly negative rate of MD change in patients suggests a genuine, continued deterioration in these patients not reflected by RNFLT changes.

Effect of cataract surgery on retinal nerve fiber layer thickness parameters using scanning laser polarimetry (GDxVCC)

Purpose:

To study the effect of cataract extraction on the retinal nerve fiber layer (RNFL) thickness, and assessment by scanning laser polarimetry (SLP), with variable corneal compensation (GDx VCC), at the glaucoma service of a tertiary care center in North India.

Materials and Methods:

Thirty-two eyes of 32 subjects were enrolled in the study. The subjects underwent RNFL analysis by SLP (GDx VCC) before undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation (Acrysof SA 60 AT) four weeks following cataract surgery. The RNFL thickness parameters evaluated both before and after surgery included temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and nerve fiber index (NFI).

Results:

The mean age of subjects was 57.6 ± 11.7 years (18 males, 14 females). Mean TSNIT average thickness (μm) pre- and post-cataract surgery was 49.2 ± 14.1 and 56.5 ± 7.6 (P = 0.001). There was a statistically significant increase in RNFL thickness parameters (TSNIT average, superior average, and inferior average) and decrease in NFI post-cataract surgery as compared to the baseline values. Mean NFI pre- and post-cataract surgery was 41.3 ± 15.3 and 21.6 ± 11.8 (P = 0.001).

Conclusions:

Measurement of RNFL thickness parameters by scanning laser polarimetry is significantly altered following cataract surgery. Post the cataract surgery, a new baseline needs to be established for assessing the longitudinal follow-up of a glaucoma patient. The presence of cataract may lead to an underestimation of the RNFL thickness, and this should be taken into account when analyzing progression in a glaucoma patient.

Effect of posterior capsular opacification removal on scanning laser polarimetry measurements

PURPOSE

To evaluate the effect of posterior capsular opacification (PCO) on retinal nerve fiber layer (RNFL) retardation measurements obtained during scanning laser polarimetry (SLP). We are unaware of previous studies undertaken in this sense.

METHODS

SLP was performed using GDx variable corneal compensation (VCC) on 28 eyes of 28 non-glaucomatous patients with clinically significant PCO, previous uneventful cataract surgery and no other ocular pathology, both before and after Nd:YAG capsulotomy. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) and SLP examination parameters prior and following PCO removal were compared using the Student t-test and Wilcoxon's test. Spearman correlations between BCVA and SLP measurements before and after capsulotomy were also performed.

RESULTS

PCO removal was associated with an increase of BCVA (P<0.0001), nerve fiber indicator (NFI) (P<0.0001) and typical scan score (TSS) (P<0.0001). In parallel, significant decreases of all absolute parameters were observed after capsulotomy. IOP, symmetry, superior ratio, inferior ratio and temporal-superior-nasal-inferior-temporal (TSNIT) standard deviation (SD) revealed no changes. Before capsulotomy, marked correlation existed between the BCVA and some SLP measurements such as nasal average (r= -0.703; P<0.0001) or NFI (r= 0.564; P=0.0017). After PCO removal these correlations were no longer found.

CONCLUSIONS

PCO removal changes SLP measurements. Therefore, new measurements to serve as a baseline for future comparisons should be obtained after Nd:YAG capsulotomy. Furthermore, some SLP measurements were significantly associated with BCVA before capsulotomy, suggesting that this technology may be useful to quantify PCO degree in non-glaucomatous patients.

Scanning laser polarimetry of nerve fiber layer thickness in normal eyes after cataract phacoemulsification and foldable intraocular lens implantation

PURPOSE

To assess the effect of cataract phacoemulsification and intraocular lens (IOL) implantation on retinal nerve fiber layer (RNFL) thickness using scanning laser polarimetry (SLP).

SETTING

Eye Clinic, Trieste University, Italy.

METHODS

Forty-eight eyes were evaluated prospectively the day before and 30 days after cataract phacoemulsification and foldable IOL implantation. In each eye, lens opacity grading according to the Lens Opacities Classification System III (LOCS III), and axial length (AL) measurements were performed. Retinal nerve fiber layer thickness was quantified at baseline by means of SLP and anterior segment birefringence compensation was evaluated acquiring macular retardation map (MRM). Acrylic and silicone IOLs were implanted randomly. After surgery, RNFL thickness was reevaluated, and MRM was reacquired. Macular retardation map pattern variations regarding baseline profile were classified into 3 groups: no variation, bow-tie profile enhancement, or attenuation. Distribution of IOL power, AL, and cataract type in the 3 groups was assessed, as were presurgery and postsurgery SLP parameters with mean values (+/-SD) compared by paired t test.

RESULTS

Twenty-two eyes (Group 1, 45.8%) showed no MRM variation, 14 (Group 2, 29.2%) an enhancement, and 12 (Group 3, 25%) an attenuation. In Group 1, no significant RNFL thickness variation occurred. In Group 2, variation 10% to 15% was measured, whereas thickening a 8% to 15% thinning appeared in Group 3. Variations occurred irrespective of IOL material, AL, or cataract type.

CONCLUSIONS

Cataract surgery with IOL implantation was associated with an MRM profile change and RNFL thickness variations in 54.2% of eyes. Variations are probably related to opacified lens removal. A new baseline SLP reading is mandatory after cataract surgery.