Roberto Gonzalez-Salinas

Patient considerations in cataract surgery – the role of combined therapy using phenylephrine and ketorolac

Cataract, a degradation of the optical quality of the crystalline lens, progressive and age-related, is the leading cause of treatable blindness worldwide. Cataract surgery is the most common surgical procedure performed by ophthalmologists and is the only effective treatment for cataracts. Advances in the surgical techniques and better postoperative visual outcomes have progressively changed the primary concern of cataract surgery to become a procedure refined to yield the best possible refractive results. Sufficient mydriasis during cataract removal is critical to a successful surgical outcome. Poor pupil dilation can lead to serious sight-threatening complications that significantly increase the cost of surgery and decrease patients comfort. Mydriasis is obtained using anticholinergic and sympathomimetic drugs. Phenylephrine, an α1-adrenergic receptor agonist, can efficiently dilate the pupil when administered by intracameral injection. Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) like ketorolac, which inhibit the synthesis of prostaglandins, are used to decrease intraoperative miosis, control pain and inflammation associated with cataract surgery, and to prevent the development of cystoid macular edema following surgery. Recently, a new combination of phenylephrine and ketorolac (Omidria®) has been approved by United States Food and Drug Administration for use during cataract surgery to maintain intraoperative mydriasis, prevent miosis, and reduce postoperative pain and inflammation. Clinical trials have shown that this new combination is effective, combining the positive effects of both drugs with a good safety profile and patient tolerability. Moreover, recent reports suggest that this combination is also effective in patients with high risk of poor pupil dilation. In conclusion, cataract is a global problem that significantly affects patients’ quality of life. However, they can be managed with a safe and minimally invasive surgery. Advances in surgical techniques and newer pharmacological agents such as the combination of phenylephrine and ketorolac, together with better intraocular lenses, have greatly improved visual outcomes and thus patients’ expectations regarding visual recovery are also increasing.

Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD

Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.

Videographic Assessment of Glaucoma Drop Instillation

ABSTRACT Purpose: To assess the effect of patient education on videotaped topical instillation of artificial tear drops on subsequent topical instillation. Materials and methods: Forty-five patients, who had been using glaucoma drops for at least 6 months and with a best-corrected visual acuity of 20/100 or better, were studied. The patients were asked to instill an artificial tear drop using their accustomed technique while being video recorded. The patients viewed the recordings, and the errors in their drop instillation method were pointed out. This was followed by an educational session on proper drop instillation technique. After 30 minutes, patients were videotaped instilling drops to ascertain the effect of the educational session. The variables compared were: number of drops instilled, number of drops reaching the ocular surface, and the number of times the tip of the medication bottle touched the eye or ocular adnexa. Results: Before the instruction session, patients squeezed an average of 1.5 ± 0.9 drops from the bottle, and the average number of drops reaching the conjunctival fornix was 0.9 ± 0.7. The tip of the bottle touched the ocular adnexa in 29/45 (64.4%) patients. After the education session, the patients squeezed an average of 1.2 ± 0.5 drops and an average of 1.2 ± 0.4 drops reached the conjunctival fornix. The tip of the bottle touched the ocular adnexa in 13/45 (28.9%) patients. With proper instructions, the percentage of patients that instilled just one drop on the eye increased from 66 to 82%. Conclusion: A single educational session on the proper use of topical drops improves the successful instillation of eye drops. However, it was not determined whether the patients will retain the improved instillation technique for long-term or if the intervention results in only a short-term improvement. How to cite this article: Lazcano-Gomez G, Castillejos A, Kahook M, Jimenez-Roman J, Gonzalez-Salinas R. Video-graphic Assessment of Glaucoma Drop Instillation. J Curr Glaucoma Pract 2015;9(2):47-50.

Current Anti-Integrin Therapy for Ocular Disease

ABSTRACT The integrin family of cell adhesion molecules mediates homeostasis, signal transduction, and various other interactions between the cell and the extracellular matrix. Integrins are type-1 transmembrane glycoproteins located on the cell surface, widely expressed in leukocytes, which play an important role in the inflammatory pathway. The purpose of this review is to summarize the current state of anti-integrin therapy and to assess ongoing clinical trials in ocular disease. We performed a search on PubMed, CINAHL, and Embase for the published literature available using the MeSH terms: “integrin therapy” and “αLβ2,” “α4β1” and “α4β7,” “αvβ3,” “αvβ5,” and “αvβ1” and/or “ophthalmology,” and “clinical trials.” We used no language restrictions. We generated searches to account for synonyms of these keywords and MESH headings as follows: (1) “integrin,” “therapy,” or “treatment”; (2) “clinical trials,” “ophthalmology,” or “ocular.” In addition, the analysis included phase 2 and phase 3 clinical trials with a minimal follow-up of six months. Integrin antagonists have shown their capacity to improve signs and symptoms of patients with dry eye disease, age-related macular degeneration, diabetic macular edema, and vitreomacular traction.

Transpalpebral Electrical Stimulation as a Novel Therapeutic Approach to Decrease Intraocular Pressure for Open-Angle Glaucoma: A Pilot Study

Purpose To determine the effect on intraocular pressure of transpalpebral specific exogenous voltages in a cohort of open-angle glaucoma patients. Methods This is a prospective, comparative, and experimental pilot study. The electrical stimuli applied consisted of 10 Hz, biphasic, nonrectangular current pulses (100 μA) delivered from an isolated constant current stimulator. At intake, baseline IOP measurements were obtained from each eye. The measurement was repeated before and after microstimulation until the end of the treatment. Results Seventy-eight eyes of 46 patients diagnosed with POAG were studied: 58 eyes with maximum tolerated medical treatment and 20 eyes without treatment (naïve). The mean baseline IOP on the treated POAG group was 19.25 mmHg ± 4.71. Baseline IOP on the naïve group was 20.38 mmHg ± 3.28. At the four-month follow-up visit, the mean IOP value on the treatment group was 14.41 mmHg ± 2.06 (P < 0.0001). The obtained mean IOP measurement on the treatment-naïve group was 15.29 mmHg ± 2.28 (P < 0.0001). Conclusions The hypotensive response obtained using transpalpebral electrical stimulation on POAG patients, both on treatment-naïve patients and on patients receiving maximum tolerable treatment, was statistically significant when comparing basal IOP measurements to those obtained at the four-month follow-up visit.

OVERPRODUCTION OF DIFFERENT β-AMYLOID PEPTIDES IN RETINA, OPTIC NERVE AND VISUAL CORTEX IN HEALTHY AGING AND ALZHEIMER'S DISEASE

(CsA). Patch-clamp results suggest that Ab-suppression of Kv1.1 involves both PP2B-dephosphorylation and direct protein-protein interaction of Ab with Kv1.1 channel subunits. Exposure of inside-out single Kv1.1 in ripped-off oocyte patches to application of purified, catalytically-active PP2B produced gradual reductions in p(open), followed by abrupt disappearance of Kv1.1 activity. Application of Ab to the intracellular face of Kv1.1 channels also produced dramatic reductions in p(open). Additional results indicate that 2 mM of Ab(25-35) suppressed Kv1.1 currents by w40%. Using “tip-dip” artificial membrane methods, 1 mM Ab(25-35) exposure eliminated Kv1.1 channel activity when applied to the intracellular face. Conclusions: The toxic Ab fragments (1-42) and (25-35) suppress the voltage-gated potassium channel, Kv1.1. Suppression of Kv1.1 and related K channels presynaptically could lead to larger and longer action potentials, allowing more influx of Ca, increased release of glutamate, and possibly the beginning of a disruption of Ca homeostasis. Postsynaptically, the increased glutamate release, through activation of AMPA and NMDA receptors, may contribute to excitotoxicity.

Molecular Age-Related Changes in the Anterior Segment of the Eye

Purpose To examine the current knowledge about the age-related processes in the anterior segment of the eye at a biological, clinical, and molecular level. Methods We reviewed the available published literature that addresses the aging process of the anterior segment of the eye and its associated molecular and physiological events. We performed a search on PubMed, CINAHL, and Embase using the MeSH terms “eye,” “anterior segment,” and “age.” We generated searches to account for synonyms of these keywords and MESH headings as follows: (1) “Eye” AND “ageing process” OR “anterior segment ageing” and (2) “Anterior segment” AND “ageing process” OR “anterior segment” AND “molecular changes” AND “age.” Results. Among the principal causes of age-dependent alterations in the anterior segment of the eye, we found the mutation of the TGF-β gene and loss of autophagy in addition to oxidative stress, which contributes to the pathogenesis of degenerative diseases. Conclusions In this review, we summarize the current knowledge regarding some of the molecular mechanisms related to aging in the anterior segment of the eye. We also introduce and propose potential roles of autophagy, an important mechanism responsible for maintaining homeostasis and proteostasis under stress conditions in the anterior segment during aging.

Glaucoma Medication Preferences among Glaucoma Specialists in Mexico

Aim To determine the glaucoma specialists’ preferences for the different brands of topical glaucoma medications available in Mexico. Materials and methods A web-based survey was sent to 150 board-certified glaucoma specialists in Mexico, with 14 questions related to brand preferences for all glaucoma medications available in Mexico. Participants were asked to select each glaucoma medication class by brand and to state the factors leading to their choice. Results Data from 111 (74%) glaucoma specialists were collected. Imot (timolol 0.5%; Sophia, Mexico) was the preferred brand for the beta-blockers (BB) class by 71% (n = 79) of the participants. Azopt (brinzolamide 1%; Alcon Lab, US) was the preferred carbonic anhydrase inhibitor (CAI) by 54% (n = 60) of the glaucoma specialists. Lumigan (bimatoprost 0.01% and 0.03%; Allergan Inc., U.S.) was the first choice for the prostaglandin analogues (PGAs) in 62% (n = 70) of the answers. The most frequently prescribed alpha-agonist (AA) was Agglad (brimonidine 0.2%; Sophia Lab, Mexico) in 44% (n = 49) of the answers. Medication accessibility (31%), cost (29%), and recommended dose (23%) were the three main factors influencing the glaucoma specialists’ preferences. Conclusion Medication cost and accessibility, as well as posology, remain the main factors influencing brand preferences among glaucoma doctors. In our professional opinion, the therapeutic effect must be the leading factor when prescribing topical medications in the daily practice, so that patients receive the best treatment option. Clinical significance This survey provides an understanding of the decision-making process when prescribing glaucoma medications by glaucoma specialists in a Latin American developing country. Ideally, patient treatment should be individualized and aimed to achieve the best results possible for their specific condition. How to cite this article: Lazcano-Gomez G, Alvarez-Ascencio D, Haro-Zuno C, Turati-Acosta M, Garcia-Huerta M, Jimenez-Arroyo J, Castañeda-Diez R, Castillejos-Chevez A, Gonzalez-Salinas R, Dominguez-Dueñas F, Jimenez-Roman J. Glaucoma Medication Preferences among Glaucoma Specialists in Mexico. J Curr Glaucoma Pract 2017;11(3):97-100.

Neovascular Glaucoma: A Retrospective Review from a Tertiary Eye Care Center in Mexico

ABSTRACT Aim To describe the demographic characteristics, ocular comorbidities, and clinical outcomes of patients with neovascular glaucoma (NVG) and to determine the number of patients who returned for a follow-up eye examination. Materials and methods We examined the clinical data of patients with NVG, who attended a glaucoma clinic between July 2010 and November 2014. We collected information on the demographic characteristics of the patients to include the level of education, ocular comorbidities, NVG stage, visual acuity, glaucoma medications, intraocular pressure (IOP), and the number of patients who had a follow-up ocular examination at month 1, 3, 6, and 12. Results Data from 350 patients (473 eyes) with NVG were collected. We found 91% of the cohort had proliferative diabetic retinopathy (PDR). We found blindness in both or one eye in 14% and 31% of the cohort respectively. Low vision was found in both or one eye in 14% and 32% of the eyes respectively. By 6 months follow-up, only 32% of the patients were seen at our clinic and by 12 months follow-up, this number decreased to 15%. Around 60% of the patients were on no IOP lowering drugs at the first visit. We found 53% of the cohort had an incomplete elementary school education. Conclusion The results suggest that advanced NVG is a significant ocular problem for patients referred to our clinic with just over half of the patients presenting as blind. We also found that several socioeconomic factors that had an important role in the development of PDR and NVG, specifically, educational status. Clinical significance We described the characteristics of a large cohort of patients with very advanced NVG, reflecting the fact that the strict control of the underlying disease must be the main goal of the Mexican national health system. How to cite this article Lazcano-Gomez G, Soohoo JR, Lynch A, Bonell LN, Martinez K, Turati M, González-Salinas R, Jimenez-Roman J, Kahook MY. Neovascular Glaucoma: A Retrospective Review from a Tertiary Eye Care Center in Mexico. J Curr Glaucoma Pract 2017;11(2):48-51.

Markers of Alzheimer’s Disease in Primary Visual Cortex in Normal Aging in Mice

Aging is the principal risk factor for the development of Alzheimers disease (AD). The hallmarks of AD are accumulation of the amyloid-β peptide 1–42 (Aβ42) and abnormal hyperphosphorylation of Tau (p-Tau) protein in different areas of the brain and, more recently reported, in the visual cortex. Recently, Aβ42 peptide overproduction has been involved in visual loss. Similar to AD, in normal aging, there is a significant amyloid deposition related to the overactivation of the aforementioned mechanisms. However, the mechanisms associated with visual loss secondary to age-induced visual cortex affectation are not completely understood. Young and aged mice were used as model to analyze the presence of Aβ42, p-Tau, glial-acidic fibrillary protein (GFAP), and presenilin-2, one of the main enzymes involved in Aβ42 production. Our results show a significant increase of Aβ42 deposition in aged mice in the following cells and/or tissues: endothelial cells and blood vessels and neurons of the visual cortex; they also show an increase of the expression of GFAP and presenilin-2 in this region. These results provide a comprehensive framework for the role of Aβ42 in visual loss due to inflammation present with aging and offer some clues for fruitful avenues for the study of healthy aging.