Purpose
To determine what percentage of normal eyes follow the ISNT rule, and whether ISNT rule variants may be more generalizable to the normal population.
Design
Cross-sectional study.
Methods
Setting: Institutional setting. Study Population: 110 normal subjects. Observation Procedures: Neuroretinal rim assessments from disc photos and RNFL thickness measurements from spectral domain OCT. Main Outcome Measures: The percentages of subjects that obeyed the ISNT rule and its variants.
Results
The ISNT rule is only valid for 37.0% of disc photo rim assessments and 43.8% of RNFL measurements. Deviation of the nasal sector from the expected ISNT pattern was a major cause for the ISNT rule not being obeyed for both rim and RNFL assessments. Specifically, 10.9% of subjects had wider nasal rims than the inferior rims, 29.4% had wider nasal rims than the superior rims, 14.7% had narrower nasal rims than the temporal rims, and 42.9% had thinner nasal RNFLs compared to the temporal quadrant. Exclusion of the nasal quadrant from the ISNT rule significantly increased the validity of ISNT variant rules, with 70.9% and 76.4% of disc photos following the IST rule and the IS rule, respectively. Similarly, for RNFL thickness, 70.9% and 71.8% of patients followed the IST and IS rule, respectively.
Conclusions
The ISNT rule is only valid for about a third of disc photos and less than half of RNFL measurements in normal patients. ISNT rule variants, such as the IST and IS rule, may be considered, as they are valid in over 70% of patients.
Intereye RNFL asymmetry may be a useful clinical OCT measurement to provide quantitative assessment of early glaucomatous damage. Newly developed algorithms for intereye RNFL asymmetry may improve the ability to detect glaucoma.
Purpose: Interest in micro-invasive glaucoma surgery (MIGS) has exploded over the last 8 years with an increase in MIGS procedures of at least 400% in the United States, according to Medicare data. MIGS is an umbrella term that can cover many different types of surgeries. This review focuses on peer-reviewed evidence for Trabectome ® , iStent inject ® , Kahook Dual Blade ® , XEN ® Gel Stent, and Hydrus ® . Methods: We present key recent studies evaluating the efficacy and safety of MIGS in various types of glaucoma patients with different stages of disease. Conclusion: We conclude that MIGS is generally safe and efficacious, although only some MIGS have been studied through randomized clinical trials. When comparing and contrasting the different MIGS procedures, large prospective studies are not yet the norm. High-quality large prospective studies involving MIGS will be an important next step as ophthalmologists decide how to incorporate MIGS into their surgical armamentarium.
Background/Objective
To report the initial outcomes of phacoemulsification, endoscopic cyclophotocoagulation, and dual blade ab interno trabeculectomy (PEcK), and compare them to those of phacoemulsification, endoscopic cyclophotocoagulation, and trabecular micro-bypass stent insertion (ICE-1).
Subjects/Methods
Patients from January 2018 to December 2019 that underwent PEcK or ICE-1 at a tertiary referral centre were included in this retrospective comparative case series. Patients were excluded if they had additional concomitant procedures, less than 6 weeks (42 days) of follow-up or were not at least 18 years old. Intraocular pressure (IOP), number of glaucoma medications, and best-corrected visual acuity were collected preoperatively and postoperatively at 6 weeks, 3, 6, and 12 months. Kaplan–Meier survival analysis and Cox proportional-hazards regression were conducted to elucidate any factors associated with survival time.
Results
The mean preoperative IOP was 18.3 ± 5.9 mmHg in the PEcK group (53 eyes) and 14.7 ± 4.3 mmHg in the ICE-1 group (23 eyes) (p = 0.004) on 3.3 ± 1.3 and 1.7 ± 0.93 glaucoma medications (p < 0.001), respectively. Twelve months postoperatively the mean IOP reduction was 5.1 ± 4.4 mmHg and 2.3 ± 4.0 mmHg (p = 0.08), and the mean medication reduction was 1.6 ± 1.5 and 0.97 ± 0.66 (p = 0.10), in the PEcK and ICE-1 groups, respectively. Kaplan–Meier survival analysis did not reveal any differences in treatment survival.
Conclusions
Both PEcK and ICE-1 provide clinically relevant reductions in IOP and glaucoma medication burden, however the PEcK procedure may confer greater reductions in IOP. The procedures did not differ with regard to Kaplan–Meier survival probability.
This study assesses the safety and efficacy of microinvasive glaucoma surgery (MIGS) with cataract extraction in patients with normal-tension glaucoma (NTG). In our sample of 45 NTG patients, mean intraocular pressure (IOP) decreased from 13.7 to 12.3 mmHg at 2.5 years, and mean medication burden decreased from 2.0 to 1.1 at 1.5 years. For success defined as IOP reduction ≥ 30% from baseline IOP with medication burden reduction from preoperative levels, success probability was 5.4% at 1.5 years. For success defined as medication burden reduction with an IOP reaching goal IOP as determined by the glaucoma specialist, success probabilities were 67.2% at 1.5 years and 29.4% at 2.5 years. At the last follow-up visit, eyes with two MIGS procedures with different mechanisms of action achieved successful medication reduction 68.8% of the time versus 35.7% achieved by a single MIGS procedure (p = 0.052). At their last visit, visual acuity was unchanged or improved in all eyes (100%). MIGS with cataract surgery results in modest reductions in IOP and medication burden in NTG patients, which may lead to lower costs and better therapeutic compliance. A combination of two MIGS procedures with different mechanisms of action may potentially be more effective in reducing medication burden than a single MIGS procedure in NTG patients. Further research is necessary to ascertain whether MIGS for NTG patients may help decrease medication burden while helping achieve goal IOP.
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