Effect of Prostaglandin Analogues on Central Corneal Thickness: 3-Year Follow-up Results

Comparing corneal biomechanic changes among solo cataract surgery, microhook ab interno trabeculotomy and iStent implantation

Minimally invasive glaucoma surgery has expanded the surgical treatment options in glaucoma, particularly when combined with cataract surgery. It is clinically relevant to understand the associated postoperative changes in biomechanical properties because they are influential on the measurement of intraocular pressure (IOP) and play an important role in the pathogenesis of open-angle glaucoma (OAG). This retrospective case-control study included OAG patients who underwent cataract surgery combined with microhook ab interno trabeculotomy (µLOT group: 53 eyes of 36 patients) or iStent implantation (iStent group: 59 eyes of 37 patients) and 62 eyes of 42 solo cataract patients without glaucoma as a control group. Changes in ten biomechanical parameters measured with the Ocular Response Analyzer and Corneal Visualization Scheimpflug Technology (Corvis ST) at 3 and 6 months postoperatively relative to baseline were compared among the 3 groups. In all the groups, IOP significantly decreased postoperatively. In the µLOT and control groups, significant changes in Corvis ST-related parameters, including stiffness parameter A1 and stress‒strain index, indicated that the cornea became softer postoperatively. In contrast, these parameters were unchanged in the iStent group. Apart from IOP reduction, the results show variations in corneal biomechanical changes from minimally invasive glaucoma surgery combined with cataract surgery.

Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions

Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.

Effects of topical prostaglandin therapy on corneal layers thickness in primary open-angle glaucoma patients using anterior segment optical coherence tomography

PURPOSE

To evaluate the effects of latanoprost, bimatoprost, and travoprost eye drops and their preservatives on each corneal layer thickness in patients with primary open-angle glaucoma (POAG).

METHODS

We retrospectively analyzed 79 eyes of 79 patients with POAG who were receiving prostaglandin therapy. Patients were divided into three subgroups according to monotherapy with latanoprost, bimatoprost, and travoprost during a mean of 43.14 ± 19.12 months follow-up period. In addition, the central corneal epithelial thickness (CET), central corneal stromal thickness (CST), and total central corneal thickness (CCT) were measured by anterior segment optical coherence tomography (AS-OCT) at baseline and every six months after treatment initiation at each visit between 9 and 12 o'clock in the morning. Furthermore, intraocular pressure (IOP) was measured with Goldmann applanation tonometry (GAT) after AS-OCT measurements at each visit.

RESULTS

All three groups were not significantly different in age, gender, follow-up period, and mean intraocular pressure values (p > 0.05 for all). The reduction of CCT in the latanoprost, bimatoprost, and travoprost groups was 6.53 ± 3.17, 18.59 ± 8.42, and 10.1 ± 1.13 µm, respectively. The decrease in CST values was 4.65 ± 1.54, 15.84 ± 7.47, 9.69 ± 1.45 µm, and CET values were 1.88 ± 1.66, 2.75 ± 0.73, 0.41 ± 0.54 µm in all groups, respectively. A statistically significant thinning was observed in all corneal layers (p < 0.05) except the CST values in the latanoprost group and CET values in the travoprost group. However, no significant difference was found in the average reduction of CET, CST, and CCT values among the three groups (p > 0.05).

CONCLUSION

Topical treatment with latanoprost, bimatoprost, and travoprost affects each layer of the cornea separately according to the active and protective substances contained in these eye drops. On the other hand, the thinning effect on the corneal layers was similar in these three drugs because there was no significant difference between the three groups in the total amount of thinning of the corneal layers during the follow-up period.

The Multifarious Effects of Various Glaucoma Pharmacotherapy on Corneal Endothelium: A Narrative Review

Corneal endothelium is a single cell layer that is mainly responsible for maintaining corneal clarity. Endothelial damage secondary to toxicity, stress, or genetic predisposition are common and in conjunction with the low regenerative ability of the cells, making their preservation critical for maintaining visual acuity. Patients with glaucoma, who are estimated to be close to 80 million worldwide, have a plethora of reasons for developing endothelial damage, being exposed to a spectrum that extends from various medical and surgical interventions to the disease itself. The wide spectrum of glaucoma pharmacotherapy that has been recently extended by addition of newer classes of medications has been the focus of extensive research on its effects on corneal endothelium. Both basic and clinical research have attempted to shine a light on the complex mechanisms associated with the effects of glaucoma medication on corneal endothelium and to answer the important question as to whether these findings are clinically significant. The aim of this review is to summarize and present current literature of the various findings, both from in vivo and in vitro studies that have focused on the complex relationship between different classes of glaucoma medication and their effect on corneal endothelium.

Comparison of two analyzer measurements focusing on material stiffness among normal, treatment-naïve, and treated glaucoma eyes

To investigate differences in biomechanical properties focusing on stiffness parameters between normal, treatment-naïve primary open-angle glaucoma (POAG), and treated POAG eyes. Retrospective case-control study, This study included 46 treatment-naïve POAG eyes, 46 POAG eyes treated with prostaglandin analogues, and 49 normal eyes used as controls; matched in terms of age and axial length. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using an ocular response analyzer (ORA). Fifteen biomechanical parameters were measured with the Corneal Visualization Scheimpflug Technology (Corvis ST), including biomechanical glaucoma factor (BGF) and two stiffness parameters of 'SP A1' and 'stress-strain index (SSI)', which were compared among the three groups. Additionally, the area under the curve (AUC) values of the receiver-operating curve to discriminate control and treatment-naïve POAG eyes were calculated for BGF and CH. Treatment-naïve POAG eyes had higher 'SSI' than normal eyes even after controlling for IOP (p < 0.05, Tukey-Cramer test). Treated POAG eyes had significantly lower CRF, and higher BGF than treatment-naïve POAG eyes. There were also significant differences in CH or SP A1 among the three groups. BGF and CH had similar AUC values (0.61 and 0.59). Treatment-naïve POAG eyes had stiffer corneas compared to normal eyes, which seemed to result from the material/structure of the cornea rather than higher intraocular pressure. Antiglaucoma topical medication alters biomechanical properties measured with Corvis ST. These results are important for understanding the pathogenesis and improving the management of POAG.

The Effect of Prostaglandin Analogs on Central Corneal Thickness of Patients with Glaucoma or Ocular Hypertension: A Systematic Review

BACKGROUND

Prostaglandin analogs (PGAs) are first-line antiglaucoma agents that appear to either decrease or increase central cornea thickness (CCT), creating controversy regarding the benefits of PGAs in treating CCT.

PURPOSE

We performed the first meta-analysis of observational studies to evaluate the effects of PGAs on CCT in patients with glaucoma or ocular hypertension (OHT).

METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A literature search was performed of the PubMed, Embase, Cochrane Library, System for Information on Grey Literature in Europe (Open Grey), and ClinicalTrials.gov databases and the references of retrieved studies. Only observational studies were included in the meta-analysis. The final CCT of patients and 95% confidence interval (CI) of each study were extracted. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ). A fixed-effects model was used to calculate the weighted mean difference (WMD) and 95% CI. Subgroup analyses based on several stratified factors such as public bias (Begg's test) and sensitivity analyses were performed.

RESULTS

Five cohort, 5 case-control, and three cross-sectional studies including 2,722 subjects were included. The pooled effect of all thirteen studies showed that PGAs reduced the CCT of patients with glaucoma or OHT slightly but significantly (WMD = -9.37; 95% CI [-12.18, -6.57]; p = 0.00; I2 = 45.5%). Significant effects were also observed in all three study designs: cohort (WMD = -5.17; 95% CI [-9.52, -0.82]), case-control (WMD = -15.31; 95% CI [-22.66, -7.97]), and cross-sectional (WMD = -8.65; 95% CI [-17.30, -0.01]). In addition, subgroup analysis of exposure time showed the effect of PGAs to be more obvious in the first (WMD = -5.81; 95% CI [-9.49, -2.14]) and second (WMD = -13.73; 95% CI [-20.19, -7.28]) years.

CONCLUSIONS

The pooled effects of previously reported studies suggest that PGA use can reduce the CCT of patients with glaucoma or OHT slightly but significantly, with this effect more pronounced in the first 2 years. These findings suggest that clinicians must closely monitor changes in CCT in the first 2 years of PGA use to identify cases of intraocular pressure misestimation and the efficacy of PGAs.

A Narrative Review of Ocular Surface Disease Related to Anti-Glaucomatous Medications

Topical anti-glaucomatous medications are still the most important measure to lower intraocular pressure. Large number of studies have confirmed that long-term use of anti-glaucomatous eye drops, especially containing benzalkonium chloride, a preservative, can cause or aggravate ocular surface injury. Ocular surface diseases damage the ocular microenvironmental health status, reduce the patients’ compliance with the treatment, and finally affect the treatment result. Therefore, the ocular surface management of patients with glaucoma is very important. This includes the selection of drugs that are better tolerated according to individual conditions, preservative-free formulations, drugs that protect against ocular surface disease, or selecting surgery and laser treatment, to prevent the damage to the ocular surface by topical anti-glaucomatous drugs.

Changes in Corneal Epithelial Thickness Induced by Topical Antiglaucoma Medications

Corneal thickness measurement is important for assessing intraocular pressure in patients with glaucoma. This study investigated the changes in corneal epithelial thickness (CET) induced by antiglaucoma medications and explored the factors affecting CET measurement. CET was measured over a 9.0 mm diameter area by using Fourier domain optical coherence tomography in 125 patients with primary open-angle glaucoma and 125 age-matched controls without glaucoma. The influence of sex, age, benzalkonium chloride (BAK)-containing instillations, disease severity, and types and numbers of medications was analyzed using simple and multiple regression analyses. CET over 25 sectors was smaller in the glaucoma group than in the control group (mean difference of 4.2 µm in the central 2.0 mm zone; 52.8 ± 3.6 vs. 48.5 ± 3.9, p < 0.001). Simple regression analysis revealed age, use of β-blockers, prostaglandin, carbonic anhydrase inhibitors, total number of medications, and number of daily BAK-containing instillations were associated with a thinner epithelium. Multiple regression analysis revealed β-blockers, prostaglandin, and number of BAK-containing instillations were significant factors. Use of β-blockers and number of BAK-containing instillations were also associated with a thinner epithelium in the monotherapy subgroup analysis. CET was significantly smaller in patients with glaucoma receiving topical medications and was affected by the use of β-blockers, prostaglandin, and BAK.