The objective of this study was to determine the efficiency of UV blocking monomers in contact lenses in providing eye protection from UV radiation. The spectral transmission of 8 contact lenses (7 soft contact lenses: Precision UV, Acuvue 2, Surevue, Omega, Encore UV, Durasoft 3 and Lunelle UV and 1 rigid gas permeable contact lens: Boston 7) was evaluated by using a dual beam spectrophotometer. Durasoft 3, a non UV absorbent contact lens was used as the control. The results showed that Precision UV contact lens absorbed UV light up to wavelength of 380 nm, whereas Acuvue 2 and Surevue absorbed up to 360 nm only. Omega, Encore UV and Lunelle UV lenses absorbed UV light up to 335 nm with spectral transmission of Lunelle UV being the highest among all soft contact lenses tested, which was 17%. Boston 7 could absorb UV light up to 385 nm, but the amount of UV light transmitted was higher than soft lenses, which was 30%. Durasoft 3 only blocked UV light at 200-245 nm. Precision UV lens had better UV blocker characteristics than the other contact lenses tested. UV blocking soft contact lenses could be an alternative for spectacles in protecting internal ocular structures from UV radiation.
It is possible that different techniques used to measure axial length (AL) and anterior chamber depth (ACD) is the cause of discrepancy in refractive outcomes of cataract surgery. This study evaluated the agreement and repeatability of AL and ACD measurements using immersion and contact A-scan biometry techniques and compared the refractive outcomes from both techniques. Twenty four patients were evaluated for agreement and repeatability of AL and ACD measurements using the two different methods. The results were analyzed using Bland and Altman plots. Another 60 patients with age-related cataract were selected to compare the refractive outcomes between both methods. The IOL power was calculated using Sanders- Retzlaff- Kraff- Theoretical (SRK-T) equation. Refraction was determined between four to six weeks postoperatively and the results were analyzed using paired t-test. The results of this study showed good agreement between both techniques was noted with no significant difference detected between measurements (p > 0.05). Significant correlation was found in all parameters (AL: r = 0.99; p < 0.01, r = 0.99; p < 0.01) ACD: r = 0.91; p < 0.01, r = 0.97; p < 0.01). No significant difference in refractive outcomes of post cataract surgery was detected between the two techniques (p = 0.07). This study concludes that contact A-scan biometry and immersion techniques provide reliable results and should not be the cause of discrepancy in the refractive planned and outcome of cataract surgery.
The aim of this study was to determine the effect of time of measurement on central corneal thickness in young myopes.
Seventy healthy myopic subjects (non contact lens wearers) were involved in this study with mean age of 22.43 ± 1.76
years. Subjective refraction was determined using cross-cylinder technique, corneal curvature was measured using
keratometer (Shin-Nippon) and central corneal thickness (CCT) was determined using specular microscope (Topcon
SP-3000P). The CCT was measured in the morning (between 8 to 11 am) and in the afternoon (between 2 to 5 pm). The
results showed that the mean of refraction for all subjects was -2.59 ± 1.85 DS and mean of cornea curvature was 7.74
± 0.25 mm. Mean CCT in the morning was 517 ± 37 μm and 516 ± 36 μm in the afternon. Statistical analysis showed no
significant difference between both measurements (T = 1.713 and P = 0.091). Correlation analysis showed insignificant
correlation between CCT and refractive error (r = -0.078, p > 0.05) and CCT with corneal curvature in the horizontal
meridian (r = 0.014, p > 0.05) and at vertical meridian (r = 0.029, p > 0.05). This study concluded that there is no
significant effect of time of measurement on CCT in young myopes
The purpose of this study is to determine the standard value of corneal thickness (CCT) and its relationship with the degree of myopia amongst one sample of myopic students in Malaysia. Eighty-four myopic subjects (168 eyes) were examined in this study. Ocular examination included subjective refraction, keratometry (Shin-Nippon, Japan) and optical pachometry (Sonogage INC). Corneal thickness was measured at five different locations i.e. central, superior, inferior, nasal and temporal of the cornea. However, only association of CCT with myopia is reported in this article. Mean age of subjects was 21.42 ± 1.47 years old (20.34 ± 1.15; 22.46 ± 0.88). Mean refractive error in spherical equivalent for the whole sample was –3.50 ± 2.10 DS. Mean corneal curvature for the all subjects was 7.74 ± 0.52 mm and mean value of CCT was 594.62 ± 66.51 mm. Significant differences (p < 0.05) were found between mean CCT of low myopes (-4.00DS and below) and higher ones (-4.25DS and above), but not with mean of keratometer readings. Poor correlations were obtained between refractive error and CCT (r = 0.125, p > 0.05) and between refractive error and corneal curvature (r = 0.24, p > 0.05). It was concluded from this study that high myopic subjects has significantly thinner CCT than lower ones. Measurement of CCT should be considered when undertaking procedures such as LASIK and orthokeratology.
It is well established the efficacy of orthokeratology (OK) treatment in improving refraction and visual acuity (VA) of low myopic subjects. However, limited data is available on high myopes. The purpose of this study was to investigate the changes of refraction, VA and contrast sensitivity (CS) over time in high myopic school children after 1 week of overnight OK treatment. A total of 19 high myopic school children were fitted with OK lenses. Mean refraction at baseline was -6.29±1.25 DS. Refraction was conducted using cross cylinder method and LogMAR chart. CS was evaluated using Pelli-Robson and FACT charts. All measurements were taken at baseline, 1, 2, 3 and 7 days after overnight OK. Data was analyzed using repeated measures of ANOVA. The results showed that refraction and CS were significantly improved throughout the study period (p<0.05). Significant changes in all parameters were noted after the first overnight treatment. Mean refraction and unaided VA after 7 nights of treatment was -0.64±1.17DS and 0.08±0.29, respectively. The results from Pelli-Robson and FACT charts showed improvement comparable to aided baseline values (p>0.05). This study concludes that overnight OK reduces refraction but does not compromise VA and CS in high myopic children within the study period. Further studies are needed to determine the long term impact of OK treatment on visual functions in a larger sample of high myopic children.
Growing application of radiatioUniversiti Kebangsaan Malaysian sources and lack of awareness among workers in practicing protective measures imply
an increased risk of radiation exposure to eye. This study determined the status of colour vision and its association with
working duration amongst staff working with radiation in a university hospital. A total of 55 employees (28 exposed (RS)
and 27 not directly exposed to radiation (NRS)) were recruited and 30 employees were used as controls. Visual acuity (VA)
was measured using Snellen chart. Colour vision assessments were conducted using Ishihara plates, D15 panel and FM
100 hues and the results were analysed using one way ANOVA. The subjects’ age ranged between 29 and 44 years old.
Mean VA for all subjects was 6/6. More than 50% of the subjects has colour defects, 3.45% of RS failed D15, 37.93%
failed FM 100 hue, 7.4% of NRS failed D15 and 55.56% failed FM 100 hue. Significant difference was found in the total
error scores between RS (77.10 ± 6.05) and NRS (84.89 ± 7.76) with the controls (41.47 ± 3.10) [ANOVA F(2,83)=16.084,
p=0.00]. There was no association between working duration and severity of colour defect [r(104)= -0.123, p>0.05].
This study concludes that majority of the studied subjects has color deficiency but not significantly correlated with their
working duration. Protective measures need to be taken to improve the situation.
The purpose of this study was to examine the effects of mild cognitive impairment on pattern electroretinogram (pERG)
among urban elderly Malays. A total of 36 subjects aged 60 years and above comprising of 18 MCI subjects and 18
normal controls were recruited for this study. The inclusion criteria for both the MCI and normal subjects included best
corrected distance visual acuity ≥ 6/9 (Snellen) with refractive error less than ±4.00 DS and/or ±2.00 DC (astigmatism),
near visual acuity ≥ N8, absence or no previous history of any significant media opacities, retinal disorders and ocular
pathologies. pERG was recorded with the RetiPort/Scan21 system in accordance with the International Society for the
Clinical Electrophysiology of Vision standards. The target presented to subjects through a 19” CRT monitor was a black
and white reversing checkerboard with luminance equal to 80 cd/m2
, contrast 97% and stimulus frequency 2.00 Hz (4
rev/s). Amplitudes and implicit times of P50 and N95 waves generated by the system were noted and compared between
the two groups. The results showed no significant difference in the amplitude and implicit times between the right and left
eyes so only the right eye was used for comparison between the MCI and control groups. The mean amplitude and implicit
times of the right eye of the MCI and control groups were 1.86±0.65 μV, 56.27±6.20 ms and 1.54±0.74 μV, 56.15±4.98 ms,
respectively. T-test showed no significant differences in pERG amplitudes and implicit times between MCI and the control
groups. In conclusion, our results may imply that the inner retina is intact in early MCI elderly subjects.
The first aim of this study was to determine the refractive error and visual acuity of Chinese elderly age 60 and above in Selangor and Johor, Malaysia. The second aim was to determine the percentage of elderly with vision impairment. Participants of this study were from the on-going population-based longitudinal study on neuroprotective model for healthy longevity (TUA) among Malaysian older adults using multistage random sampling. A total of 259 Chinese elderly aged 60 and above from state of Selangor and Johor agreed to participate. Refractive error was determined using autorefractometer Retinomax K-plus followed by subjective refraction. Best corrected visual acuity (VA) was measured using logMAR chart. Analysis was performed on data of 202 participants and the remaining 57 were excluded. Overall percentage of refractive error was higher for hyperopia (54%) compared to myopia (23.2%). High percentage of astigmatism was noted for all age groups (> 50%). Both gender showed similar distribution of refractive status. Mean overall VA was 0.24 ± 0.17 logMAR (≅ 6/9-) and mean VA declined with age. Overall, the percentage of elderly having at least mild vision impairment (> 0.3 logMAR or 6/12) was higher (62.9%) compared to normal vision (≤ 0.3 logMAR). However, percentage of vision impairment (VI) was highest in the mild category compared to others and only one participant had severe VI. This study found a high percentage of Chinese elderly with refractive error. The most common type of refractive error was hyperopia. A high proportion of them had mild vision impairment followed by moderate VI even with best correction. Vision impairment could affect daily life functioning and this effect can be further explored in the future.
A vision screening study was carried out among Indian schoolchildren around Kuala Lumpur to determine whether the prevalence of myopia was higher in boys or girls. Altogether 749 students (49.7% boys and 50.3% girls) aged 7-18 years were screened and their refractive error examined using retinoscopy without cycloplegia. For the right eye 15.1% of the girls' eyes were found to be myopic as compared to 16.9% of the boys, of which chi-square showed no significant difference (p = 0.44). For the left eye 18.8% of the girls' eyes were myopic as compared to 16.4% of the boys. Chi square also showed no significant difference (p = 0.26). When high myopia (> -6.00D) was considered, there was no difference found between boys and girls. The number of students with high myopia greater than -6.00D was also very small (0.3%-0.5%). In conclusion, it was found that there was no significant difference in myopia between girls and boys among Indian schoolchildren.
Kajian terdahulu banyak menunjukkan perbezaan dalam dimensi okular mengikut kaum. Walau bagaimanapun hanya terdapat sedikit data mengenai dimensi okular bangsa Melayu di Malaysia yang dilaporkan. Kajian ini bertujuan untuk menetapkan nilai normal dimensi okular bangsa Melayu muda di Malaysia. Seramai 584 orang telah diundang untuk menjadi subjek untuk kajian secara sukarela. Pengukuran yang dilakukan meliputi kelengkungan dan ketebalan tengah kornea, nilai esentrisiti kornea (e), diameter iris horizontal dan vertikal yang kelihatan, saiz pupil dan bukaan palpebral. Subjek dibahagikan kepada 3 kumpulan berikut mengikut umur dan dipadankan mengikut jantina dan umur: Kumpulan 1 (7-12 tahun, n = 188), Kumpulan 2 (13 to 18 tahun, n = 196) and Kumpulan 3 (19 to 24 tahun, n = 200). Pengukuran dilakukan menggunakan topografer kornea (CTK 922 dari Haag Streit, Jerman), pakometer ultrasonik (Corneo-Gage Plus 2 dari Sonogage Incorporated) dan auto refraktometer (Auto-Ref R1 dari Canon, Jepun). Dimensi okular bangsa Melayu yang diukur didapati lebih kecil dari bangsa lain di seluruh dunia. Perbezaan yang signifikan juga didapati untuk semua pengukuran dengan peningkatan umur (p < 0.05). Keputusan kajian ini boleh dijadikan rujukan untuk nilai dimensi okular populasi Melayu muda Malaysia di masa hadapan.
This study was conducted to determine the score of self-reported visual function index (VF-14) and its correlation with
best corrected visual acuity (BCVA) in the elderly population. Participants were elderly aged 60 years and above recruited
from the on-going population-based longitudinal study on neuroprotective model for healthy longevity (TUA). Visual
acuity was measured using logMAR chart. A self-reported visual function assessment was measured using modified
Bahasa Malaysia Visual Functioning Index (VF-14). A total of 482 (93.05%) from 518 subjects participated in this study.
Mean age was 69.18 ± 5.67 years old and mean best corrected VA was 0.21 ± 0.17 logMAR. Mean VF-14 score was 89.65
± 13.19. Female had lower mean score of self-reported visual function scores compared to male (meanfemale89.21 ± 12.76,
meanmale90.11 ± 13.65) but it was not statistically significant (z = -1.09,p = 0.277). There was a moderate but significant
correlation between VF-14 score and best corrected VA (r = -0.412, p < 0.01). In conclusion, the best corrected visual
acuity alone was not able to become as an indicator to describe changes in VF14 score. This study showed that it only
contributes 17.2% to changes in VF14 score. The combination of many other factors such as socio-demographic factors
(race, educational status, and health problems), contrast sensitivity and stereopsis should be taken into account when
assessing visual function as measured by VF14.