Open Access Systematic Review Article

A Systematic Review: What is the Normative Size of the Blind Spot Scotoma in Adults?

Martin J Rhodes

Ophthalmology Research: An International Journal, Page 51-66
DOI: 10.9734/OR/2013/4789

Background: Blind spot enlargement can be caused by a range of medical conditions and monitoring the size of the blind spot scotoma can indicate progression of disease.

Objectives: The aim of this review is to establish the size of the blind spot scotoma in adults free of ocular pathology in order to aid identification of any scotoma enlargement. 

Search Methods: The following electronic databases were searched; Ovid Medline, Ovid SP, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Google Scholar and the Cochrane Central Library.

Searches were then conducted of the following individual journals; British Medical Journal, British Journal of Ophthalmology, Journal of Neurology, European Journal of Neurology, Archives of Ophthalmology, American Academy of Ophthalmology, Ophthalmology, Brain, and Eye.

Selection Criteria: No study designs were to be excluded. Few relevant articles were found and so no publication timeframes were imposed.

Results: The identified literature is reviewed and discussed in relation to the equipment used to measure the size of the blind spot scotoma. The equipment used to measure the blind spot scotoma included; Tangent Screen, Goldmann, Tubingen Computer Campimeter, Stereo-campimeter and Ferree-Rand. This review found the size of the blind spot scotoma to be dependent on the method used to measure it.

Conclusion: Clinicians need to have accurate information on the instruments they use to successfully monitor changes in the size of the blind spot scotoma. Further research needs to be conducted using clinically relevant equipment, such as the Octopus 900 which allows clinicians to move the kinetic stimulus at a constant speed and account for the patient’s reaction time.

 

Open Access Minireview Article

Genetic Predisposition to Advanced Retinopathy of Prematurity (ROP) Gains Support

Barkur S. Shastry

Ophthalmology Research: An International Journal, Page 31-37
DOI: 10.9734/OR/2013/4731

Aims: The purpose of this short review is to summarize the recent developments in the genetics of retinopathy of prematurity.

Background: Retinopathy of prematurity is a well known blinding disorder in children in both developed and developing countries. It is characterized by the hypovascularization of the peripheral retina in children with a short gestational age and low birth-weight. Morphologically it is similar to familial exudative vitreoretinopathy (FEVR) but FEVR patients do not have the history of oxygen therapy and prematurity. ROP is a life time disease and patients can still have long-term effect even after timely treatment. Although many causative factors have been suggested, the pathogenesis of ROP is not understood. Some of the unpredictability of ROP could be due to genetic factors.

Methodology: Using the key words or phrases such as ROP, genetics, animal models and pediatric retinal disorders, the literature search was carried out.

Results: Molecular genetic analysis has identified mutations in three of the four FEVR causing genes in patients with advanced ROP in different ethnic backgrounds. These three genes are involved in a highly regulated Wnt signaling pathway that controls the development of the retinal vasculature. The genetic association of ROP was further supported by the higher concordance rate of the disorder in monozygotic twins, racial variation, strain dependent difference in oxygen-induced ROP in inbred rats and the existence of quantitative loci on chromosome 7 and 9 that modify susceptibility to oxygen-induced ROP.

Conclusion: Although much remains to be done in the field of ROP, the above finding supports a role for the Wnt signaling pathway in the development of severe ROP. The availability of animal models may provide opportunities for the development of novel therapeutic approaches to prevent or treat this pediatric blinding disorder.  

 

Open Access Original Research Article

Formulation and Physical Characterization of a Novel Sustained-Release Ophthalmic Delivery System for Sparfloxacin: the Effect of the Biological Environment

Abd EL- Gawad H. Abd EL- Gawad, Osama A. Soliman, Susan A. Barker, Germeen N.S. Girgis

Ophthalmology Research: An International Journal, Page 1-22
DOI: 10.9734/OR/2013/2442

Aims: The purpose of this study was to prepare and evaluate ocular thermosetting gels containing sparfloxacin-HP-β-CyD. The formulations based mainly on Pluronic F127 alone or combined with other polymers.

Study Design: Experimental study.

Place and Duration of Study: School of Pharmacy, University of East Anglia, Norwich, Norfolk, UK, between July 2010 and January 2011.

Methodology: Sparfloxacin, the more effective fluoroquinolone antibiotic used in ocular infection was prepared in form of 1:2 drug: HP-β-CyD spray dried complex. The complex was characterized by several techniques like DSC, FTIR and SEM. In this study, the possibility of incorporation of this complex into thermosetting gels was investigated using pluronic F127 alone or combined with other polymers. All placebo and medicated formulations were characterized physically (colour, clarity, pH, and drug contents). Rheological tests and texture analysis were performed in both non physiological conditions, and after dilution with the simulated tear fluid, to estimate the effect of the biological environment effect on thermosetting gels properties.

Results: Sparfloxacin-HP-β-CyD complex was successfully prepared and characterized by several techniques, all confirmed complete inclusion between sparfloxacin and HP-β-CyD. The prepared complex showed a significant improvement in the aqueous solubility of Sparfloxacin compared to untreated drug or the physical mixture. Ocular thermosetting gels containing sparfloxacin-HP-β-CyD complex were prepared simply by cold method using 20% Pluronic F127 alone or 15% Pluronic F127 combined with other polymers. All preparations were found colourless or yellow, clear, of acceptable pH, and drug content.

The rheologicaly and texture analysis studies revealed that, the formulations exhibited suitable gelling temperatures, gelling times, and appropriate strength to be used in ocular dosage forms. The biological environment highly affected gel properties according to the polymer type.

Conclusions: Ophthalmic in-situ gelling formulations containing sparfloxacin-HP-β-CyD complex are considered promising delivery systems. They showed good rheological and texturale properties. The results confirmed the possibility of lowering Pluronic F127 concentration by using other polymers in small concentrations. The effect of the biological environment must be considered in developing such formulations.

 

Open Access Original Research Article

Periodic Blood Glucose Test and Its Relationship with Diabetic Retinopathy among Patients with Diabetes in a Tertiary Ophthalmic Centre

You Chuen Chin, Srinivasan Sanjay, Ee Lin Ong, Sun Yan, Kah Guan Au Eong

Ophthalmology Research: An International Journal, Page 23-30
DOI: 10.9734/OR/2013/4298

Aim: To assess the awareness of periodic blood glucose test and its relationship with diabetic retinopathy among adult diabetic patients attending a tertiary ophthalmic centre.

Study Design: Cross-sectional study.

Place and Duration of Study: Ophthalmology and Visual Sciences, Alexandra Hospital, between January and February 2007.

Methodology: An interviewer-administered survey was administered to 506 participants with diabetes mellitus, aged 23 to 88 years old (mean: 62.1 years).

Results: Only 296 (58.5%) participants were aware of the relationship between periodic blood glucose test and diabetic retinopathy. Participants who were Indians (p=.01) or had a highest education level of primary school (p=.04) were less aware. However, participants with higher education had higher awareness (p=.01). The age- and gender-adjusted odds ratio (OR) of having diabetic retinopathy was 0.54 (95% confidence interval (CI): 0.38-0.78, p=.001). On multivariate adjustment, results remained statistically significant (OR: 0.49, CI: 0.31-0.77, p=.002).

Conclusion: Periodic blood glucose test awareness is lower in Indians and those who were less educated. Participants were who aware of periodic blood glucose test were less likely to have diabetic retinopathy.

 

Open Access Original Research Article

Prospective Pilot Study Looking at the Size and Variation of the Blind Spot Scotoma in Adults Measured on the Octopus 900 Field Analyser

Martin J Rhodes

Ophthalmology Research: An International Journal, Page 38-50
DOI: 10.9734/OR/2013/4790

Aims: Literature regarding the size of the blind spot is old and recorded on instruments no longer in production. This pilot study looks to provide normative data for the size of the visual blind spot scotoma in adults measured by the Octopus 900 kinetic perimeter.

Study Design:  A prospective repeated measures study involving nineteen participants.

Place and Duration of Study: Ophthalmology department, Royal Hallamshire Hospital, Sheffield, between April 2012 and July 2012.

Methodology: The blind spot scotoma area was measured in degrees2 using three kinetic targets. Two trials were conducted to assess variability across the targets.

Results: The mean blind spot scotoma area decreased as target luminosity increased. The mean blind spot scotoma area was; 197.6±152.8 deg2 with the I1e, 63.6±21.7 deg2 with the I2e and 33.9±6.8 deg2 with the I4e.

Agreement between the first trial and second trial for the three different forms of target luminance was examined using Bland-Altman analysis. The target I4e has the closest mean difference to zero and the I4e also has the highest precision as shown by the SD; I1e bias -1.764±3.852SD, I2e bias -0.368±0.938SD and I4e bias -0.151±0.477SD.

Conclusion: This study found the mean size of the blind spot scotoma to be influenced by the luminosity of the target stimulus, with mean area (deg2) decreasing as target luminosity increases. This can be attributed to the blind spot’s amblyopic zone or light scattering across the refractive media of the eye. The target I4e shows the least variation between subsequent measures and would be the most reliable of the targets used for monitoring change in blind spot scotoma area over time.

 

Open Access Original Research Article

Comparison of Ocular Alignment Using Corneal Reflex Measurements with Plusoptix S08 between Non–strabismic Amblyopes and Normal Controls

Goktug Demirci, Mustafa Ozsutcu, Banu Arslan, Mustafa Eliacik, Gokhan Gulkilik, Selim Kocabora

Ophthalmology Research: An International Journal, Page 67-73
DOI: 10.9734/OR/2013/3614

Aims: Purpose of this study is to compare corneal reflex value measurements performed by the Plusoptix S08 photo-screener between anisometropic non–strabismic amblyopic children and non-amblyopic children.

Study Design: This is a randomized and controlled prospective study.

Place and Duration of Study: Department of Ophthalmology, Medical Faculty of Istanbul Medipol University between September 2012 and December 2012.

Methodology: Corneal reflex values of 39 amblyopic non-strabismic children and 28 normal children were compared after complete ophthalmoscopic examination by the same examiner. Only patients with anisometropic amblyopia without strabismus were included in the study group and only non-amblyopic children were included in the control group.

Results: There was no statistical significance between the study and the control group in means of age (p=0.100) and sex distribution (p=0.818). Corneal reflex values of the

amblyopic eyes was 3.8±3.2 degrees and corneal reflex values of normal eyes was 2.4±4.1 degrees. There was no statistical significance between study and control group in means of corneal reflex values (p=0.127).

Conclusion: Although Plusoptix has proved to be a reliable screener in terms of measurement of refraction, we did not know whether the corneal reflex value was also a reliable screening value, because there is no research about this value in the literature. According to the current literature this is the first research examining the corneal light reflex reliability of a Plusoptix S08 photo-screener and, in light of our results, the corneal reflex value of Plusoptix S08 is not a reliable tool for the screening of amblyogenic risk factors in non-strabismic children.