Corneal thickness and morphology after orthokeratology of six-month lens wear among young Malay adults

@#Background: Menicon Z night orthokeratology (OK) lenses was introduced in Malaysia in 2015 and to date there is no report on its effects on the cornea. The objective of this study was to examine short term changes in corneal thickness and morphology of endothelial cells in young Malay adults after wearing Menicon Z night OK lenses. Methods: Corneal thickness was measured at the central and mid-peripheral locations of 20 participants aged 22.45±1.19 years using Tomey SP-3000 A-scan ultrasonography. Endothelial images of the central and peripheral locations captured using Tomey EM-3000 specular microscope were noted. Corneal thickness, endothelial cell density (ECD), coefficient of variation in cell size (CV), and hexagonality (HEX) at baseline, 24 hours, three months and six months after treatment were noted and analysed using repeated measure analysis of variance. Results: Central corneal thickness decreased significantly over a three-month period (p=0.001) and stabilised thereafter. There were no significant changes in thickness in all peripheral areas measured (p>0.05), and in ECD, CV and HEX after the six-month period (p>0.05). Conclusions: The current study showed that significant thinning of central cornea and none at the mid-periphery. OK lens wear with Menicon Z night lenses had no effects on corneal morphology over the six month period.

Tear Stability, Corneal Staining and Dry Eye Symptoms in Contact Lens Wearers / Jurnal Sains Kesihatan Malaysia

@#The aim of this study was to examine tear stability of contact lens wearers (CLW) in young Malay adults aged 18 and above and to compare the results with non-contact lens wearers (NCLW). Corneal staining and McMonnies Dry Eye Questionnaires (MDEQ) scores between habitual soft CLW and NCLW were also compared. It also aimed to find correlation between tear stability and MDEQ scores. Quasi-experimental and case control study was conducted among 53 participants (53 right eyes) at UiTM Vision Care, UiTM Puncak Alam Campus. Twenty six participants were habitual soft CLW and twenty seven were NCLW. Tear stability was measured using non-invasive tear break-up time (NIBUT) and invasive tear break-up time (TBUT). Corneal staining was measured using Efron Grading Scale and dry eye symptoms evaluated using MDEQ. Mean scores of NIBUT and TBUT for CLW were 5.23 ± 7.3 sec and 2.19 ± 2.41 sec respectively; for NCLW were 8.71 ± 4.33 sec and 3.00 ± 1.69 sec respectively. There were significant differences in NIBUT (Mann-Whitney U, p=0.0001) and TBUT (Mann-Whitney U, p=0.001) between the CLW and NCLW. There was also significant difference in percentage of corneal staining found between the CLW (22.6%) and NCLW (7.5%), (Chi-square, p=0.013). However no significant difference was found in MDEQ scores between the CLW (7.54 ± 3.62) and the NCLW (8.15 ± 3.38) group, (Mann-Whitney U, p=0.42). There were also no correlations found between tear stability and MDEQ scores in the two groups. The results of this study showed NIBUT and TBUT values were significantly higher in NCLW than in CLW and corneal staining was more extensive in CLW. Contact lens practitioners need to be aware of changes in tear stability as results of contact lens wear and take the necessary action to improve on the management of their patients during aftercare consultation.

Pattern Visual Evoked Potential (VEP) is Unaffected in the Early Stage of Mild Cognitive Impairment / Jurnal Sains Kesihatan Malaysia

The aim of this study was to determine whether pattern-reversal Visual Evoked Potential (PRVEP) is affected in mild cognitive impairment (MCI). Participants aged ≥ 60 years diagnosed as MCI were invited to participate in a study together with a group of controls. PRVEP was measured using A RETI-port/Scan 21 and stimuli of large and small checks sizes, 1° (60 min of arc) and 0.25° (15 min) respectively were used to obtain responses. The amplitude and implicit times of the MCI and control groups were then compared. A total of 18 MCI participants (age 65.7 ± 3.1 years) and 18 controls (65.1 ± 3.8 years) consented to participate in the study. The amplitude and implicit times for the MCI group using the target sizes of 60 min of arc were 9.80 ± 4.06 μV and 108.83 ± 7.63 ms and for 30 min of arc were 11.00 ± 7.44 μV and 123.96 ± 6.18 ms respectively. Consecutively for the control groups the amplitudes and implicit times were 8.96 ± 3.52μV, 105.85 ± 3.60 ms and 11.97± 6.11 μV, 122.57 ± 8.28 ms. PRVEP results did not reveal significant differences in P100-wave amplitude nor implicit time between the two groups under investigation. This study concluded that the visual pathway of MCI participants may be unaffected in the early part of the disease process.

Custom Made Ocular Prosthesis at Optometry Clinic Universiti Kebangsaan Malaysia (UKM) / Jurnal Sains Kesihatan Malaysia

Patients who lost their eyes as results of accidents or diseases (e.g. retinoblastoma) usually underwent enucleation or evisceration. They were then fi tted with ocular prosthesis to prevent collapse of the globe and also for cosmetic effects. Custom made ocular prosthesis is almost unheard of in this country for most hospitals supply ready-made (stock) prosthesis. The cosmetic results of stock prosthesis are often unsatisfactory. Besides being uncomfortable, stock prosthesis may also induce allergic reaction that may lead to papillary conjunctivitis. The Optometry Clinic at UKM started its custom made prosthetic service in 2010. We described here two cases of patients who complained of discomfort with their old stock prosthesis and re-fi tted with custom made prosthesis. We also highlight the importance of proper hygiene and maintenance so that ocular prosthesis can be used for as long as possible. This article aims to create awareness among eye care practitioners and showcase the cosmetic benefi ts of custom made ocular prosthesis

Survey of Contact Lens Care Among Contact Lens Wearers in Kuala Lumpur / Jurnal Sains Kesihatan Malaysia

Contact lenses are optical device that are supposedly safe to be used to correct refractive errors as well as for cosmetic purposes. However problems related to eye health do occur as result of contact lens wearers’ attitude of not following the guidelines prescribed by their eye care practitioners. A clinical survey on lens care was carried out amongst contact lens wearers in Kuala Lumpur. It was based on a set of 22 questions focused on lens care including methods of cleaning and disinfection, enzyme treatments, use of rewetting agents and the frequency of follow-up examinations. In addition there were six questions included to explore wearers’ knowledge related to contact lens care and safety. A total of 104 wearers participated in the survey. About 86% of them were females and their mean age was 24 ± 6 years. More than half of them wore disposable lenses. Almost all of them (98%) use chemical disinfection system. Sixty-eight percent (68%) of wearers surveyed cleaned their lenses prior to and after wearing their lenses. Thirty percent (30%) of wearers used re-wetting agents and 40% used protein tablets. Sixty-one percent (61%) of them said that they never went back for aftercare examinations. The mean correct responses for six questions assessing participants’ knowledge on contact lens care and safety was 61.4%. Our results implied that contact lens wearers were not well informed of the risks and consequences to their eye health as results of not following the strict regimes recommended by their practioners. Contact lens providers should reconsider strategies to ensure wearers’s compliance so that complications can be minimized

Variation in Measurement of Pattern Electroretinogram (pERG) / Jurnal Sains Kesihatan Malaysia

Pattern electroretinogram (pERG) is a recording of retinal response to a phase reversing pattern stimulus. It gives information on the integrity of the inner retina specifically the ganglion cells. The recording of pERG in a laboratory is easily influenced by many factors hence standardization in a laboratory is required to ensure that pERG recorded is repeatable and reproducible. The objective of this study was to determine the factors that could affect pERG recordings at the Electrophysiology Laboratory, Optometry Program, Faculty of Health Sciences (FSK), Universiti Kebangsaan Malaysia (UKM). This study involved forty-five subjects, aged between 20 and 25 years. They were divided into three groups. The factors being investigated were effects of 1) Alcaine 0.5%, 2) diurnal variation and 3) different size and shape of fixation target for pERG measurement (amplitude and implicit time). Paired t-test showed no significant differences between the recording before and after instillation of Alcaine 0.5% for amplitude (p = 0.116) and implicit time (p = 0.557). Measurements carried out in the morning and afternoon did not show significant differences for amplitude (p = 0.864) and implicit time (p = 0.174). For different fixation targets, results also showed no significant difference for amplitude (p = 0.125) and implicit time (p = 0.404). In conclusion, use of Alcaine 0.5%, different time of measurements and different type of fixation targets do not influence pERG results at the Electrophysiology Laboratory, FSK, UKM. Results of this study can be used for comparisons in research or in diagnosing diseases of the retina in the future

Optometric Practice in Private Sector Around Kuala Lumpur and Klang Valley: A Preliminary Study / Jurnal Sains Kesihatan Malaysia

This survey was carried out to examine the habits of practising optometrists in private practice around Kuala Lumpur and the Klang Valley. A questionnaire survey was prepared that encompassed questions on ophthalmic intruments and appliances, services offered, eye examinations carried out and patient management, failure to carry out comprehensive eye examination, community engagements and their opinion on optometrists as primary eyecare practitioners. The questionnaire was sent to 100 registered optometrists practising in Kuala Lumpur and the Klang Valley. About 64 optometrists responded and returned the questionnaire, but 3 of them were excluded because they were incomplete. The results showed almost all optometric practice has all the equipment related to optometry practice except for tonometer and visual field measurement. Forty-four percent (44%) of optometrists undertook comprehensive eye examinations and if necessary referred patients for further examinations. Optometrists who did not perform comprehensive eye examinations give reasons of inadequate equipment and clients who want a quick examination. In conclusion optometric practice provide almost all the equipments required for optometrists to practice as primary health care practioners but only 44% of optometrists carried out comprehensive eye examinations. Optometrists in private practice need to practice all the skills they learned and play important roles in educating the public in an effort to improve the primary eyecare of society

A Survey of Optometric Contact Lens Prescribing in Malaysia / Jurnal Sains Kesihatan Malaysia

This survey represents an initial examination of contact lens practice in Malaysia. It is based on a questionnaire that was sent to selected members of the Association of the Malaysian Optometrists to survey the prescribing habits of g contact lenses and care products. Questions included types of lenses prescribed, care systems frequently recommended and types of complications seen. Optometrists in Malaysia prescribed an average of 90 new pairs of contact lenses per year. Soft lenses made up 84% of the prescription followed by 14% of rigid gas permeable lenses and 1.5% of polymethymethacrylate lenses. Disposable/frequent replacement lenses accounted for 60% of the soft lenses prescribed. The most commonly prescribed disinfecting system was chemical disinfection. The most common complication seen during aftercare consultation was dry eye-related problems.

The resin-embedded cornea prepared via rapid processing protocol: A good histomorphometric target for clinical investigation in opthalmology and optometry

This study illustrates and quantifies the changes on corneal tissue between the paraffin-embedded and resin-embedded blocks and thus, selects a better target in investigational ophthalmology and optometry via light microscopy. Corneas of two cynomolgus monkeys (Macaca fascicularis) were used in this study. The formalin-fixed cornea was prepared in paraffin block via the conventional tissue processing protocol (4-day protocol) and stained with haematoxylin and eosin. The glutaraldehyde-fixed cornea was prepared in resin block via the rapid and modified tissue processing procedure (1.2-day protocol) and stained with toluidine blue. The paraffin-embedded sample exhibits various undesired tissue damage and artifact such as thinner epithelium (due to the substantial volumic extraction from the tissue), thicker stroma layer (due to the separation of lamellae and the presence of voids) and the distorted endothelium. In contrast, the resin-embedded corneal tissue has demonstrated satisfactory corneal ultrastructural preservation. The rapid and modified tissue processing method for preparing the resin-embedded is particularly beneficial to accelerate the microscopic evaluation in ophthalmology and optometry.