Open Access Original Research Article

Presbyopia and Vision-related Quality of Life in Calabar South, Nigeria

Egbula N. Eni, Afiong Oku, Roseline E. Duke

Ophthalmology Research: An International Journal, Page 1-11
DOI: 10.9734/or/2019/v10i330105

Aim: To determine the magnitude of presbyopia and the effect of uncorrected presbyopia on vision-related quality of life in Calabar South, Nigeria.

Study Design: A community-based, descriptive cross-sectional study.

Place and Duration of Study: Calabar South Local Government Area, Nigeria, between November 2016 and February 2017.

Methods: We included 422 adults (198 men, 224 women) aged 35 years and above, selected by cluster random sampling. Subjective distance refraction was done on all participants with distant visual acuity less than 6/6. Near visual acuity was assessed at 40 centimetres with a Times Roman near vision (British N system) chart, with distant correction in place if required. Presbyopia was defined as inability to read N8 at 40 centimetres unaided or with habitually worn distance refractive correction, with improvement of near vision by at least one line on a Times Roman near vision chart with use of a plus lens. An adapted and validated quality of life questionnaires were administered to the participants.

Results: A total of 422 participants were examined and interviewed. The prevalence of presbyopia was 55.5%. There was no significant association between gender and prevalence of presbyopia. The presbyopia correction coverage in the study population was 38.0% with a strong positive correlation between age and the required near vision spectacle lens power (r = 0.88, p < .001). Another key finding was a significant association between uncorrected presbyopia and reduced quality of life.

Conclusion: This study has demonstrated that the burden of presbyopia in the study population is enormous in spite of the fact that it has a cost effective intervention. The key findings in this study underscore the need to scale up presbyopic correction services in the study area.

Open Access Original Research Article

Comparison of Phaco-chop and Divide and Conquer Methods in Grade 3-4 Cataract Patients

Kenan Yiğit

Ophthalmology Research: An International Journal, Page 1-5
DOI: 10.9734/or/2019/v10i330108

Purpose: To compare the outcomes of Grade3-4 cataract surgery performed with 2 phacoemulsification techniques (phaco-chop and divide-and-conquer).

Setting: Ministry of Health Tuzla State Hospital, Istanbul, Turkey.

Design: Prospective randomized clinical trial.

Methods: This is prospective and randomized(double blind) study cataract surgery using two different techniques of nuclear fragmentation performed at the Tuzla State Hospital.100 patients eye with nuclear density from grade 3 to 4 were randomly subdivided into 2 groups (phaco-chop and divide-and-conquer). Intraoperative measurements included Phaco time (PT), effective phaco time(EPT), mean phaco power(MPP). Clinical measurements included preoperative and  postoperative 1.day , 7. day, 30. day, and 60.day corrected distance visual acuity(BCVA), time to achieve BCVA, corneal edema rate and time to disappear corneal edema.

Results: Intraoperative measurements showed significantly less PT, EPT, and corneal edema with the phaco-chop technique than divide-and-conquer techniques in the grade 3-4 cataract density group (P<0.05).

Conclusions: 2 techniques may be effective for cataract surgery in mild and moderate cataracts. However, in eyes with hard cataract the phaco-chop technique can be more effective for lens removal, with less Phaco time and corneal edema, then the divide-and-conquer technique.

Financial Disclosure: No author has a financial or proprietary interest in any material, method or device mentioned.

Open Access Original Research Article

Kinetics of Enhancement for Corneal Cross-linking: Proposed Model for a Two-initiator System

Jui-Teng Lin

Ophthalmology Research: An International Journal, Page 1-6
DOI: 10.9734/or/2019/v10i330109

Aims: To derive kinetic equations and analytic formulas for efficacy enhancement of corneal collagen crosslinking (CXL) in a 2-initiator system.

Study Design:  Modeling the kinetics of CXL.

Place and Duration of Study: Taipei, Taiwan, between between January 2019 to June, 2019.

Methodology: Coupled rate equations are derived for two initiators system for a type-II process, consisting of a primary initiator (PA), and a co-initiator (PB) as an enhancer, having 3 cross linking pathways: Two radical-mediated (or electron transfer) pathways, and one oxygen-mediated (or energy transfer) pathway. For a type-II process, the triplet state T* interacts with the co-initiator, PB, to form the primary radicals R’, and an active intermediates radical, R, which could interact with the substrate [M] for crosslink, or be inhibited by oxygen [O2], or bimolecular termination. Rate equations, based on lifetime of triplet-state and oxygen singlet-state, are used to analyze the measured results in a rose-Bengal system with an enhanced initiator.

Results: Additive enhancer-monomer of arginine added to a rose Bengal photosensitizer may enhance the production of free radicals under a green-light CXL. D2O may extends the lifetime of oxygen singlet state and thus improve the efficacy. Our formulas predicted features are consistent with the measured results.

Conclusion: Efficacy may be improved by enhancer-monomer or extended lifetime of photosensitizer triplet-state or oxygen singlet state.

Open Access Review Article

Primary Open Angle Glaucoma: The Pathophysiolgy, Mechanisms, Future Diagnostic and Therapeutic Directions

Benedict C. Umezurike, Moses Obeimen Akhimien, Okechukwu Udeala, Uzoamaka G. Green, Ugonma Okpechi-Agbo, Maureen U. Ohaeri

Ophthalmology Research: An International Journal, Page 1-17
DOI: 10.9734/or/2019/v10i330106

Primary open angle glaucoma (POAG) is a multifactorial chronic optic neuropathy, characterized by progressive loss of retinal ganglion cells (RGC), leading to structural damage to the optic nerve head (ONH), retinal nerve fiber layer (RNFL), with  visual field defects. It is occasioned by major risk factors of high intraocular pressure (IOP) and age. The pathogenesis of POAG is the imbalance between the production and drainage of the aqueous humour (AH). The resultant fluid back-up increases the IOP with consequent optic nerve damage, causing POAG. Modern diagnosis, using scanning laser polarimetry (SLP), confocal scanning laser ophthalmoscopy (CSLO), optical coherence tomography (OCT) etc, plays a vital role in the assessment of the ONH, RNFL and the macular, in POAG. OCT operates on the principles of interferometery, utilizing light beams and their pattern of back-scattering, to build high resolution cross-sectional images of ocular tissues. It gives an objective evaluation of structural alterations in the ONH or macular area of the retina in vivo. POAG is managed medically using classes of drugs like α-adrenergic agonists, beta-adrenergic receptor antagonist, prostaglandin agonists, carbonic anhydrase inhibitors, ccholinergic agonists etc. Surgical intervention is indicated with laser or incisional surgeries, when medical option fails. Future pharmacotherapeutic directions in POAG management consider transgenic model, genetic model, neuroregeneration (stem cell technique), neurodegeneration (Seeing glaucoma as a neurologic disorder much like in Parkinson's and Alzheimer's diseases and the mechanisms that cause the degeneration of RGCs), autoimmune response and T-cell autoimmune response attack.

Open Access Review Article

Ocular Adverse Effects of Antidepressants – Need for an Ophthalmic Screening and Follow up Protocol

Varsha Narayanan

Ophthalmology Research: An International Journal, Page 1-6
DOI: 10.9734/or/2019/v10i330107

Depression is emerging to be one of the commonest mental health disorders worldwide affecting a wide age group. The prescription of antidepressants has risen considerably in last decade with a preference for using newer antidepressants like Selective Serotonin Reuptake Inhibitors (SSRIs). There have been many published reports of Ocular side effects with Antidepressants related to Dry eye, Visual disturbance, Angle closure glaucoma and Retinal effects. There has also been a significant rise in antidepressant usage by the elderly, which is a population at risk for ocular adverse effects. Therefore, it is pertinent to understand the antidepressants from the perspective of their mechanisms of action and all possible Ocular adverse effects, and develop an Ophthalmic screening protocol and follow up for patients being put on Antidepressants. Patients should also be counselled for reporting alert signs of ocular side effects immediately. These steps may help to avert and decrease visual complications with Antidepressants.