Is human retina a poorly designed structure? analysis between creationist and evolutionist view

Introduction: Human retina is an inverted structure causing the light to travel multiple layers to reach the photoreceptors. Evolutionist scientist assume this a poorly designed structures. It is consider as a scar of past evolution causing the presence of blind spot. In contrast, creationist scientist refuted the idea by proposing necessary visual functions associated with the structure.Methodology: Selected articles and journals from google seached engine were chosen to analysed both view of creationist and evolutionist. Results: Evolutionist views back-wired designed lead to blindspot, detached retina, macular regeneration, angular closure glaucoma, unnecessary extraocular muscles and susceptibility to disease. On other side of coin, creationist view the design is important to avoid degradation of photoreceptors, production of high resolution of image,tolerated blindspot, good visual acuity and a superior space saving solution. Discussion: The structure of human eye demonstrated optimal condition for proper functioning of visual images.No single ultimate structures are free from diseases or deficiencies. The inverted retina structures are not uniquely to human alone. Conclusion: Future studies are needed to unravel the unique structure of human retina

The relationship between symptomatic assessment and clinical signs of dryness in dry eye subjects

Introduction: There was no previous study to assess relationship between dry eye symptoms and signs in the local population. The purpose of this study is to evaluate the relationship of symptomatic assessment and clinical signs of dryness in dry eye subjects. Materials and method: A Cross-sectional study with convenient sampling involving 321 subjects with 642 eyes was done. Subjects were divided into non-dry eye (NDE) and dry eye (DE) groups. The division of NDE and DE groups were done using two types of classification. In Classification 1(symptoms-based), DE was defined if the score of Ocular Surface Disease Index (OSDI) score was more than 33. The value of tear film break-up time (TFBUT) less than 5 seconds and Schirmer test with anaesthesia (STA) less than 5mm/5 minutes were considered as DE for Classification 2 (signs based). Results: There were poor correlations between OSDI and clinical signs of dryness in all subjects involved (p > 0.05). Similar findings were also noted within NDE subjects in Classification 1 and Classification 2. OSDI score was also not significantly correlated with the signs of dryness within DE subjects except with ocular protection index (OPI) (r = -0.14, p = 0.047) in Classification 1 and with conjunctival lissamine green staining (CLGS)(r = 0.23, p = 0.040) in Classification 2. Conclusion: There were no significant correlation between the symptoms of dry eye and the clinical signs of dry eye. Therefore, the clinical diagnosis of dry eye can be made based on either just on the symptoms or the signs

Short term effect of virtual reality on eye accommodative ability

Virtual reality (VR) is a fast-growing technology in the world today. Many countries use virtual reality for many purposes such as education, military and entertainment. Despite the benefits of VR, harmful effects of VR on the users are still inconclusive. With only a few reliable studies that investigate the effect of virtual reality on the users especially on the eyes, yet still there are a lot more things we do not know about the effects of VR. The purpose of this study was to compare the amplitude of accommodation before and after watching 3-dimesional (3D) movie utilizing VR and notebook (control group). Thirty-two participants volunteered in this study and all participants underwent amplitude of accommodation (AA) test using Royal Army Force (RAF) rule before and after watching three-dimensional (3D) movie for 30 minutes using VR and two-dimensional (2D) movie by laptop. The amplitude of accommodation between pre- and post-watching 3D movie on VR was insignificantly changed (p= >0.05). The similar trend was also found after 30 minutes watching movie using laptop (p= >0.05). The utilization of VR and laptop for 30 minutes did insignificantly alter the eye accommodation

Short term effect of virtual reality on tear film stability and ocular discomfort

Virtual reality (VR) has been integrated and used with smartphones as one of the digital entertainments such as in gaming and movie streaming. With emergent of various VR brands in the market, it concerns the public on the possible side effects of VR on the ocular performance specifically on tear film stability and ocular discomfort. The purpose of this study was to compare the change on non-invasive keratograph tear break-up time (NIKBUT), tear meniscus height (TMH) before and after the use of VR for 30 minutes, and to measure the ocular discomfort after the use of VR quantitatively. Thirty-two subjects were recruited in this study and all the subjects were divided randomly into two groups; VR and laptop (used as a control) groups. Each subject needed to watch a movie for 30 minutes using the respective devices. The changes of tear film stability and ocular discomfort before and after the use of the devices were then compared and the results showed that there was no significant difference (p>0.05) after 30 minutes of the use. Comparison of the ocular parameters between the devices on post-watching activities was also not significant (p>0.05). Use of VR did not give any signs of dryness to the eyes and it can be used without any discomfort even after 30 minutes usage of the devices

The effect of 6-prism base-out at 6-metre fixation on vergence and accommodation systems

Introduction: Prisms is used for binocularity diagnosis and vision therapy in optometry particularly in treating symptomatic vision anomalies such as divergence excess, convergence insufficiency, nystagmus and concomitant as well as incomitant strabismus. This utilization of base-out prism in the alteration of vergence and accommodation system is not well explored especially on normal binocular vision. This study aimed to assess the effect of prism base-out inducement on vergence and accommodation among normal binocular vision system. Aim: To compare the value of positive fusional vergence (PFV) and amplitude of accommodation (AA) before and after introduction of 6 prism base-out (BO) at fixation distance of 6m for 15 minutes. Methodology: Thirty participants were recruited in this quasiexperimental study and all of the participants wore the 6 prism BO for 15 minutes while watching movie at 6m. AA and PFV at 6m and 40cm were measured pre- and post-watching movie at 6m with 6 prism BO inducement. Results: The AA and PFV before and after intervention were then being compared and the results showed that there were insignificant changes (p>0.05) in AA and PFV of both eyes. Conclusion: The results suggested that the utilization of 6 prism BO in 15 minutes did insignificantly alter accommodation and vergence system

The effect of overminus prescription on positive fusional vergence value and accommodation amplitude after watching video at 6 metre

Introduction: The study aimed to investigate the effect -1.00 DS overminus prescription on positive fusional vergence (PFV) and accommodation amplitude (AA) after watching video at 6m. Method: Thirty normal participants without binocular vision anomalies (23.50 ± 1.50 years) were involved in this quasi-experimental study. All subjects wore additional -1.00 DS on the spectacle prescription for 15 minutes while watching video at 6m. The distance (6m) and near (40cm) PFV and AA were measured before and after 15 minutes watching video at 6m with the overminus prescription. Results: The result demonstrated the right eye (RE) AA reduced significantly (p<0.05) while the reduction on the left side was insignificant (p> 0.05). The changes of near and distance PFV was found insignificant (p> 0.05) after 15 minutes watching video at 6m with overminus prescription. Conclusion: Overminus prescription of -1.00DS for 15 minutes at distance fixation that presented in this study reduced the ability of accommodation. There were no changes in vergence system after intervention of -1.00 DS overminus prescription for 15 minutes at 6m

The effect of 6 prism base-out during smartphone use on vergence and accommodation systems

Introduction: Prism is used in binocular vision assessment and visual therapy. The short-term use of prism, particularly base-out prism on vergence and accommodation system, was not well-explained in the previous investigations. Aim: This current study aimed to assess the effect of 6 prism base-out for 15 minutes on vergence and accommodation system during the utilization of smartphone. Methodology: Thirty normal participants were recruited in this quasi-experimental study. All participants wore 6 prism-base out for 15 minutes while using smartphone at 40cm. Near positive fusional vergence (PFV) and amplitude of accommodation (AA) were measured before and after 15 minutes of 6 prism base-out wear during smartphone usage. Results: The results showed no significant difference for both parameters measured when comparison was made between before and after prism base-out inducement in front of eye. Conclusion: The vergence and accommodation systems presented in this study were almost identical among normal subjects after inducement of 6 prism base-out for 15 minutes during watching smartphone

Characterizing protection ability of blue blocking lenses using k-means clustering

Blue light protection ophthalmic lenses have been regularly marketed as the ultimate protection against short-wavelength visible radiation mainly in the range of 400 nm and 450 nm. However, the actual protective effects of such lenses are currently unknown; most claims are provided by the manufacturers with limited scientific validation. This will not only make selling such lenses challenging but may provide the lens wearers little or no protection against the blue light hazard. It is recently discovered that the protection needs to take into accounts the light source that the wearers wish to protect from – heavy electronic gadget users for instance, are exposed to different spectrum of radiation compared to non-users. This problem is aggravated when the hazard needs to further be classified into the visual and non-visual effects. Non-visual impact includes the disruption in the circadian cycle which is governed by the physiological cycles of our body within 24 hours such as the melatonin hormone secretion. Such knowledge will help to educate optometrist to explain to their prospective customers and will also assist the spectacle wearers to make an informed decision based on validated scientific data

Corneal Curvature Measurements Utilizing a New Swept-source Optical Coherence Tomography Tomey OA-2000® and Comparison With IOL Master® 500 in Pterygium Patients

Introduction: Corneal curvature (CC) is an important anterior segment parameter. This study compared CC measurements conducted with two optical devices in pterygium eyes.Methods: Sixty pterygium eyes of 30 patients were enrolled in this study. CC was measured three times with the optical biometer and topography-keratometer Tomey OA-2000 (Tomey Corporation, Nagoya, Japan), then with partial optical coherence interferometry (PCI) IOL Master 500 (Carl Zeiss Meditec, Dublin, CA) and data were statistically analysed.Results: The measurements revealed in a mean CC of 43.86 ± 1.57 D with Tomey OA-2000 and 43.84 ± 1.55 D with IOL Master. Distribution of data is normal, and no significance difference in CC values was detected (P = 0.952) between the two devices. Correlation between CC measurements was highly significant (r = 0. 99; P < 0.0001). The mean difference of CC values between devices was 0.017 D and 95% limit of agreement was -0.088 to 0.12. Duration taken for measurements with the standard biometer IOL Master was longer (55.17 ± 2.24 seconds) than with Tomey OA-2000 (39.88 ± 2.38 seconds) in automatic mode. Duration of manual measurement with Tomey OA-2000 in manual mode was shorter (28.57 ± 2.71 seconds).Conclusion: In pterygium eyes, CC measured with Tomey OA-2000 and IOL Master showed similar values, and high correlation was observed between these two devices. This shows that both devices can be used interchangeably. Tomey OA-2000 is better in terms of faster to operate and has its own topography systems