Corneal endothelial changes following a single session of selective laser trabeculoplasty for pseudoexfoliative glaucoma

Selective laser trabeculoplasty is safe and effective in patients previously treated with prostaglandin analogs: An evidence-based review

PURPOSE

Prostaglandin analogs (PGAs) are first-line treatments for ocular hypertension (OHT) and open-angle glaucoma (OAG). However, frequent side effects and high costs hinder patient's compliance resulting in disease progression. Evidence suggests selective laser trabeculoplasty (SLT) may be considered a first-line treatment for OHT and OAG due to its safety profile, minor side effects, and reduced costs. Considering that PGAs and SLT share action mechanisms, it is hypothesized that previous PGA therapy may affect subsequent SLT efficacy. Therefore, we analyzed if PGAs reduce SLT efficacy.

METHODS

An evidence-based review was performed to assess the safety and efficacy of SLT in patients previously treated with PGAs. For this purpose, we performed an extensive literature search using the National Library of Medicine's PubMed and Google Scholar database for all English language articles published until May 2021.

RESULTS

There is evidence of non-superiority of PGAs therapy versus SLT for OHT and OAG. A multicenter, randomized, observer-masked clinical trial (RCT) of untreated OHT and OAG patients concluded that SLT should be offered as the first-line treatment for these patients. This study was supported by a meta-analysis of RCTs, comparing SLT efficacy versus antiglaucoma drugs only, with the advantage of an SLT lower rate of adverse effects.

CONCLUSIONS

Cost-effectiveness, patient compliance, and antiglaucoma drugs' side effects, including higher surgical failure, favor consideration of SLT as first-line therapy for OAG and OHT. Furthermore, SLT efficacy does not seem to be affected by prior PGA administration; however, larger cohort, comparative, multicenter RCTs are necessary to answer this question.

Selective laser trabeculoplasty as adjunctive treatment in pseudoexfoliative glaucoma patients

Introduction/Objective. Pseudoexfoliation syndrome is characterized by abnormal production and accumulation of fibrillar, white-gray, ?dandruff-like? material in almost all ocular structures. The aim of this study was to examine effect of selective laser trabeculoplast in pseudoexfoliation glaucoma patients. Methods. Thirty-two patients (47 eyes) were enrolled with medically uncontrolled pseudoexfoliation glaucoma. All patients could not reach target intraocular pressure with maximal tolerated medical therapy before treatment. Selective laser trabeculoplasty was performed with about 100 non-overlapping spots. Intraocular pressure was measured 1 hour, 7 days, 4 weeks, 3, 6, 12, 18 and 24 months after procedure. Results. The mean base intraocular pressure was 23.45 mmHg (SD = 3.07). Statistically significant reduction of mean intraocular pressure was observed at all follow-ups except 1 hour after treatment. Mean intraocular pressure after 24 months was 18.39mmHg (SD = 1.82). Success, defined as intraocular pressure reduction from base IOP of more than 20% after 24 months, was achieved in 27 eyes (57.45%). We did not find any influence of sex and age on selective laser trabeculoplasty effects in pseudoexfoliative glaucoma patients. Baseline intraocular pressure is proved to be reliable predictor of intraocular pressure lowering effect, as there were strong correlation between baseline intraocular pressure and percentage of reduction of intraocular pressure after 24 months (r = 0.71, p < 0.01). Conclusion. Selective laser trabeculoplasty is safe and effective method for reduction of intraocular pressure in pseudoexfoliation glaucoma patients and should be used more often in this challenging form of glaucoma. Baseline intraocular pressure seems to be reliable predictor of success.

The Effects of Glaucoma and Glaucoma Therapies on Corneal Endothelial Cell Density

A healthy corneal endothelium is required for corneal clarity. Both the glaucoma disease state and its various forms of treatment can have adverse effects on the corneal endothelium. Both the presence of glaucoma and the magnitude of intraocular pressure elevation are related to endothelial cell loss (ECL). Topical medical therapy, laser procedures, and both traditional surgeries-trabeculectomy and tube-shunts-and newer minimally invasive glaucoma surgeries have variable effects on ECL. This review will summarize the reported effects of glaucoma and its treatment on ECL. Concerns for corneal endothelial cell health should be part of the decision-making process when planning glaucoma therapy for lowering intraocular pressure, with added caution in case of planned device implantation in eyes with preexisting ECL and low endothelial cell density at high risk for corneal endothelial decompensation.

Corneal endothelial status in different grades of late spontaneous in-the-bag IOL dislocation

PURPOSE

 To evaluate corneal endothelial cell density (ECD) in the eyes with different grades of late spontaneous in-the-bag intraocular lens (IOL) dislocation.

METHODS

 A prospective study included seventy-eight patients who applied for IOL dislocation. Overall 80 eyes were divided into four grades based on the in-the-bag IOL dislocation classification. All eyes underwent a complete ophthalmological examination. ECD was evaluated using in vivo corneal confocal microscopy.

RESULTS

 Median corneal ECD was 1929 (1022-2958) cells/mm2 of all the patients. The lowest number of ECD was in grade 2 (grade 1 median ECD 1990.33 (1182-2425.33) cells/mm2, grade 2-1577.0 (1022-2958) cells/mm2, grade 3-2205.84 (1259-2807.67) cells/mm2 and grade 4-2072.17 (1045-2581.0) cells/mm2). A statistically significant difference was observed between the median of ECD of grade 2nd and 3rd (p = 0.023). By grouping cases into those with and without glaucoma, we found that corneal ECD was significantly lower in eyes with glaucoma compared with eyes without glaucoma in grades 3 and 4 (p < 0.05), while in other grades, the difference did not reach the significance level. We divided the corneal ECD of all eyes into two categories ≤ 1500 cells/mm2 and  > 1500 cells/mm2. Logistic regression demonstrated that the odds of having corneal ECD less than 1500 cells/mm2 increased by 3.5-fold if patients with IOL dislocation had been diagnosed with glaucoma previously.

CONCLUSION

 Late spontaneous in-the-bag IOL dislocation reduced corneal ECD. Previously diagnosed glaucoma was the most common comorbidity. This condition has a significant impact on corneal ECD for patients with IOL dislocation.

Comparison of the effects of 180° and 360° applications of selective laser trabeculoplasty on intraocular pressure and cornea

PURPOSE

To compare the effects of 180° and 360° selective laser trabeculoplasty (SLT) on intraocular pressure (IOP) and cornea in patients with bilateral primary open-angle glaucoma.

METHODS

Fifty-two eyes of 26 patients were included. On the same day, 180° SLT (Group 1) was applied to one eye of patients and 360° SLT (Group 2) to the other eye. IOP values were compared at pre-SLT and post-SLT 1 day, 1 week, 1, 3, and 6 months. Changes in central corneal thickness (CCT) and endothelial cell count (ECC) were examined.

RESULTS

In groups, significant decreases were observed in IOP at 1 week (p < 0.05), 1, 3, and 6 months (p < 0.001). No significant difference was determined between group 1 and 2 in IOP-lowering effectiveness or success rates (p > 0.05). There was no significant difference in CCT at inter- or intragroup comparisons (p > 0.05). In group 1, no significant difference was determined in pre- and post-SLT ECC (p > 0.05). In group 2, significant decrease in ECC was observed at 1 week (p < 0.05). However, ECC returned to its initial levels at 1 month.

CONCLUSIONS

To the best of our knowledge, this is the first study in literature to compare different quadrant SLT applications performed on both eyes, on the same day, in the same patient group and to compare the effects of those applications on IOP and cornea. In reducing IOP, 180° and 360° SLT are similarly effective. These effects begin on the 1st week and persist for 6 months. Temporary corneal changes may be observed following 360° SLT.

Quantitative and Morphological Corneal Endothelial Changes After Selective Laser Trabeculoplasty and Retinal Photocoagulation

PURPOSE

Selective laser trabeculoplasty (SLT) and retinal photocoagulation (RP) are two common laser procedures often performed at a wavelength of 532 nm, and may affect the corneal endothelium. This study used corneal specular microscopy to determine the impact of these procedures on the corneal endothelium.

DESIGN

Retrospective cohort study in a private practice.

METHODS

There were 249 eyes from 136 consecutive patients who underwent SLT for open-angle glaucoma and 132 eyes from 74 patients who underwent RP included. Corneal specular microscopy was performed immediately before and after each procedure and at 1-month postprocedure. Microscopy data included quantitative measures, such as cell density and central corneal thickness, and morphological measures, including percentage of hexagonal cells and coefficient of variation in cell area.

RESULTS

There was a small (just over 1%) reduction in corneal endothelial cell count from pre-SLT to post-SLT (P = 0.008), and a statistically significant recovery at 1 month (P = 0.04). Central corneal thickness also transiently increased from pre-SLT to post-SLT (P = 0.03). Although polymegathism was unchanged, changes in pleomorphism were observed (P = 0.03). The only change in the RP group was an increase in polymegathism between pre-RP and post-RP (P = 0.001).

CONCLUSIONS

SLT has measurable effects on both quantitative and morphological characteristics of the corneal endothelium, which seem to be transient. RP has fewer measurable effects, likely because, although the total laser energy is similar, it is delivered over a much longer time (3 ns versus 0.1 s). The changes observed in both procedures are minor and unlikely to be of clinical significance.