Normal tension glaucoma management: a survey of contemporary practice

Retinal Neurodegeneration in an Intraocular Pressure Fluctuation Rat Model

Increased intraocular pressure (IOP) is the most important risk factor for glaucoma. The role of IOP fluctuation, independently from elevated IOP, has not yet been confirmed in glaucoma. We investigated the effects of IOP fluctuation itself on retinal neurodegeneration. Male rats were treated with IOP-lowering eyedrops (brinzolamide and latanoprost) on Mondays and Thursdays (in the irregular instillation group) or daily (in the regular instillation group), and saline was administered daily in the normal control group for 8 weeks. The IOP standard deviation was higher in the irregular instillation group than the regular instillation group or the control group. The degree of oxidative stress, which was analyzed by labeling superoxide, oxidative DNA damage, and nitrotyrosine, was increased in the irregular instillation group. Macroglial activation, expressed by glial fibrillary acidic protein in the optic nerve head and retina, was observed with the irregular instillation of IOP-lowering eyedrops. Microglial activation, as indicated by Iba-1, and the expression of TNF-α did not show a significant difference between the irregular instillation and control groups. Expression of cleaved caspase-3 was upregulated and the number of retinal ganglion cells (RGCs) was decreased in the irregular instillation group. Our findings indicate that IOP fluctuations could be induced by irregular instillation of IOP-lowering eyedrops and this could lead to the degeneration of RGCs, probably through increased oxidative stress and macrogliosis.

New Preservative-Free Formulation for the Enhanced Ocular Bioavailability of Prostaglandin Analogues in Glaucoma

Glaucoma is a wide-spread eye disease caused by elevated intraocular pressure. Uncontrolled, this pressure may lead to damages to the optic nerve. Prostaglandin analogues, such as latanoprost and travoprost (which are water-insoluble active substances), are the most used class of active pharmaceutical ingredient. To administer them as eye drops, preservatives, such as benzalkonium chloride, are used as solubilizers. The latter is known to cause a local inflammation when used chronically and is not recommended for patients with ocular surface disorders. In this work, we sought to use polysorbate 80 (PS80) as a solubilizing agent simultaneously with sodium hyaluronate (NaHA) as a thickener and cytoprotective agent for the corneal surface. The first part of this study assessed the compatibility of the excipients with the active substance, using physicochemical methods such as spectra fluorescence and differential scanning calorimetry (DSC), as well as the solubilization mechanism of PS80 regarding prostaglandin analogues using nuclear magnetic resonance (NMR). The second part evaluated the stability of a formula candidate, its viscosity upon instillation, and its pharmacokinetic profile in rabbits as compared to the commercially approved medicine Travatan®. The results show that sodium hyaluronate is inert with respect to travoprost, while PS80 successfully solubilizes it, meaning that benzalkonium chloride is no longer required. Moreover, the pharmacokinetic profiles of the rabbits showed that the original formula described in the present study enhanced the ocular bioavailability of the drug, making it a promising product to control intraocular pressure with a potential reduced dosage of travoprost, therefore minimizing its related side effects.

HIGHLIGHTS OF HYPERTENSIVE AND NORMOTENSIVE GLAUCOMA

The paper presents the up-to-date overview of pathogenesis, functional and structural changes in normotensive glaucoma (NTG) and its differences from hypertensive glaucoma (HTG). The autors point out new facts that distinguish both diagnostic groups. In the first place are the results of OCT angiography, which verify the pathology of NTG to the anterior part of optic nerve. Our findings confirmed that vascular component (VD) is more involved in changes of visual field than in perfusion parameters, especially in arteria ophtalmica (AO). Perfusion in arteria centralis retinae (ACR) does not play a significant role in NTG changes in the visual field. VD has very little effect on changes in visual field in HTG. Similarly, the retinal nerve fiber layer (RNFL) for changes in the visual field. Howerver, VD is moderately influenced by changes in RNFL. It should be emphasized that we compared the sum of sensitivity in the central part of the visual field (0-22 degrees) with RNFL and VD. In NTG, the anterior part of the optic nerve is altered. Mainly VD contributes to visual filed changes in NTG. It is also important to note that when the intraocular pressure (IOP) increased above 20 mm Hg, the macular and papillary VD was significantly reduced. Antiglaucomatous treatment with prostaglandins and beta-blockers is essential for the reduction of IOP in HTG. This reduction shoud be bellow 20 mm Hg, in eyes with thinner cornea the decrease in IOP should be more pronounced. It does not matter which antiglaucoma treatment was used. However, it should be noted that prostaglandins have a greater effect on disease progression, but the greater protective effect on the visual field have beta-blockers. Neuroprotectives should be recommended systemically in patients with HTG. When treating NTG, it is important to maintain blood flow of the posterior pole of the eye, but mainly of the anterior part of the optic nerve. Prostaglandins are not suitable in NTG patients, although their effect on IOL reduction is high. Beta-blockers (betaxolol and carteol) and brimonidine are most suitable. Corneal thickness has no effect on disease progression.

Normal-tension Glaucoma Management: A Survey of Glaucoma Sub-specialists in Korea

PURPOSE

To investigate the current management patterns of glaucoma subspecialists with regard to normal-tension glaucoma (NTG) in Korea and to determine the effect of the two largest NTG trials on their clinical practice.

METHODS

A questionnaire survey was sent to glaucoma subspecialist members of the Korean Glaucoma Society. The questionnaire concerned regular practice with respect to NTG and the extent to which it has been influenced by the Collaborative Normal-tension Glaucoma Study and the Low-pressure Glaucoma Treatment Study (LoGTS).

RESULTS

A total of 134 glaucoma subspecialists completed the survey, with a response rate of 56%. The survey reported that 88% and 78% of glaucoma subspecialists were familiar with the Collaborative Normal-tension Glaucoma Study and the LoGTS, respectively. With respect to mild or moderate NTG, most of the respondents (87%-91%) tended to treat their patients immediately without waiting for structural or functional progression. Among the respondents, 47 indicated that the LoGTS results-according to which, 20% of the respondents tended to use brimonidine more often-affected their management. The first-choice topical drugs for NTG were prostaglandin analogues (76%), brimonidine (9%), beta-blockers (8%), and topical carbonic anhydrase inhibitor (6%).

CONCLUSIONS

Regarding mild-to-moderate NTG, Korean glaucoma subspecialists tended to initiate treatment without waiting for further progression. The impact of the LoGTS on NTG management was not dominant in clinical practice in Korea. Prostaglandin analogs are the most frequently selected first-choice drugs for the management of NTG in Korea.

Association of Ultrapure Citicoline, Homotaurine and Vitamin E in the Management of Normotensive Glaucoma: A Case Report

Normal tension glaucoma (NTG) remains a therapeutic challenge for the ophthalmologist since there are no effective therapies as the main therapeutic target, i.e., the intraocular pressure (IOP) increase, is missed. We report on the effectiveness of two neuroprotective molecules (ultrapure citicoline plus homotaurine), in combination with a topical hypotensive approach, in the management of NTG in a long-term follow-up (30 months). A 38-year-old Caucasian woman with no significant medical history and a diagnosis of NTG, after an extensive 30-month treatment with oral dietary supplement containing ultrapure citicoline 500 mg, homotaurine 50 mg and vitamin E once per day and topical glaucoma medication (brimonidine + brinzolamide drops twice per day), presented a significantly improved automated 24-2 visual field with a controlled tonometric measurement associated with a stabilization of retinal fiber layer and ganglion cells at OCT examination with patient satisfaction. This finding suggests that ultrapure citicoline together with homotaurine and vitamin E, through a synergistic neuroprotective effect, could be a promising approach in the management of NTG.

Normal tension glaucoma in Asia: Epidemiology, pathogenesis, diagnosis, and management

Normal tension glaucoma (NTG) has similar optic neuropathy as primary open-angle glaucoma (POAG), but intraocular pressure (IOP) is within the normal range. Compared with high-pressure POAG, the development of NTG is possibly a consequence of a complex interaction of several ocular and systemic factors. Recent data have shown higher translaminar pressure gradient due to impaired cerebrospinal fluid dynamics may account for the pathogenic mechanism. Insufficient blood supply and vascular dysregulation may also be the cause of the disease. In clinical evaluation, NTG is a diagnosis by excluding other nonglaucomatous optic neuropathies. NTG is characterized by larger and deeper optic-disc cupping, more central visual field defects and a higher incidence of disc hemorrhage compared with POAG. In clinical practice, controlling IOP as low as possible (with medication, laser trabeculoplasty, or surgery) is the key to manage NTG patients. In addition to IOP reduction, the control of systemic risk factors or improving ocular perfusion may be beneficial therapies. NTG is more prevalent in Asia than in the Western countries. Due to increasing old population and underdiagnoses in the clinical settings, NTG became a great challenge for ophthalmologist in Asia. Therefore, the aim of this article is to focus on the epidemiology, to update pathogenesis, diagnosis, and management for NTG.

Management of the glaucoma patient progressing at low normal intraocular pressure

PURPOSE OF REVIEW

Patients with glaucoma with disease progression despite low or normal intraocular pressure (IOP) present special challenges to the treating clinician. Treatment goals may depend on whether patients have apparent low IOP with concurrent treatment or have low IOP at baseline without treatment. We review the diagnostic and therapeutic approaches to these patients.

RECENT FINDINGS

Apparent progression at low IOP should start with confirmation of IOP, made easier by devices enabling patient home self-tonometry. Suspected visual field progression should be confirmed by repeat testing prior to advancement of therapy. Trabeculectomy remains the most effective surgical method of achieving long-term success, particularly when there is a low starting IOP. Drainage tube implantation or the use of novel micro-incisional non-bleb-forming procedures are less likely to be successful in achieving low IOP goals.

SUMMARY

Diagnostic testing is important in confirming progressive glaucomatous disease at low IOP levels. The most effective way of slowing the progression of glaucoma in a patient with low IOP is to lower the IOP further, sometimes to single digit levels, which is most often achievable with trabeculectomy.

Betaxolol, Brimonidin and Carteolol in the Therapy of Normal-Tension Glaucoma

PURPOSE

The purpose of the study was to evaluate influence of betaxolol, brimonidine and carteolol in the progression of the visual field defects during time at patients with normotensive glaucoma (NTG).

MATERIALS AND METHODS

This study included (60 eyes of) 30 patients with NTG. First group consisted of 20 eyes of 10 patients of the average age of 58.5 years, who were treated by betaxolol. Second group also consisted of 20 eyes of 10 patients of the average age of 62.6 years and they were treated by brimonidine. Third group had the same count of the eyes and patients, the average age was 61.1 years and these patients were treated by carteolol. Diagnose of NTG was based on the comprehensive ophthalmological examination including electroretinography and visual evoked potentials. Visual fields were examined by fast threshold glaucoma test using Medmont M700 device. We compared pattern defect (PD) in the visual field for 3 years. The including criteria were: similar visual field findings at the beginning of the study, stable eye therapy (treatment was not changed during the study), uncorrected or best corrected (up to +-3 D) visual acuity of 1,0 of ETDRS, intraocular pressure between 10-15 mm Hg, if present, then compensated cardiovascular disease, no other internal or neurological disorders.

RESULTS

We didnt notice any statistically important difference of PD. The study revealed that brimonidin (p=0,99) and betaxolol (p = 0,81) had the best effect.

CONCLUSION

Local therapy of betaxolol, brimonidine and carteolol has an essential clinical value in normotensive glaucoma. All the mentioned treatments had a protective effect on the visual field. However, local side-effects of brimonidinu are a question.