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ABSTRACT: To assess the validity of the solar ultraviolet index (UVI) as a determiner of eye risk under different conditions of facial profiles and orientation, and reflected light.
Ocular UV radiation (UVR) exposure was measured as a function of the time of the day (solar altitude) using a two-dummy-type mannequin dosimetry system with embedded UVR (260-310 nm) sensors, in September and November in Kanazawa, Japan, on a motorized sun-tracking mount with one dummy face directed toward the sun and the other away from the sun.
A bimodal distribution of UV-B exposure was found in September for the face directed toward the sun, which differed dramatically from the pattern of ambient UVR exposure and measurements taken on the top of the head and those for the eye taken later in the year. Although the overall level was lower, a higher solar altitude is associated with higher UVR exposure in the condition facing away from the sun.
The UVI is based on ambient solar radiation on an unobstructed horizontal plane similar to our measures taken on the top of the head, which differed so much from our measures of ocular exposure that UVI as a determiner of eye risk is deemed invalid. The use of the UVI as an indicator for the need for eye protection can be seriously misleading. Doctors should caution patients with regard to this problem, and eye protection may be warranted throughout the year.
Eye & contact lens 07/2011; 37(4):191-5.
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ABSTRACT: To compare visual acuity and ocular higher-order aberrations (HOAs) in eyes with waterclefts, a type of crystalline lens opacity, and in normal eyes.
Department of Ophthalmology, Kanazawa Medical University, Ishikawa, Japan, and Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
In this nested case-control study of subjects attending the third examination of the Reykjavik Eye Study in 2008, eyes with pure waterclefts and control eyes with no lenticular opacity were evaluated. All candidates had complete ophthalmic examinations and wavefront analysis. Higher-order aberrations in the watercleft group and the control group were compared.
The watercleft group comprised 30 eyes and the control group, 194 eyes. The mean corrected distance visual acuity (CDVA) in the watercleft group was statistically significantly lower than in the control group (P<.01). There was a significant relationship between CDVA and HOA in both groups. Total HOA and trefoil and coma aberrations were statistically significantly higher in the watercleft group than in the control group (P<.05).
Waterclefts significantly affected CDVA. Eyes with waterclefts had higher coma and trefoil aberrations, suggesting that the increased HOAs caused reduced visual acuity in eyes with waterclefts.
Journal of cataract and refractive surgery 05/2010; 36(5):799-805. · 2.75 Impact Factor
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ABSTRACT: Sunglasses have generally been used to protect against glare. Various kinds of sunglasses which correspond to the visual environment are on the market (e.g. for driving, fishing, skiing, etc.). As for the spectral transmission factor of sunglasses, the differences that occur in user's eyes with aging have not been fully considered. We investigated the relationship between different levels of crystalline lens transparence and the effects of glare protection using two kinds of filters.
A Tri-Blocker filter (TB) and general driving filter (ActiveDrive, ADR) were used. The TB absorbs three spectral wavelengths (below 400 nm, blue light, 575 nm) and can be transparent for other visible light. The ADR reduces the light below 650 nm. TB and ADR transmit 52.5 and 29.0% of the visible light, respectively. Twenty-five normal volunteers with transparent lenses (n = 48 eyes, aged from 22 to 68 years) and 10 cortical cataract patients (n = 18 eyes, aged from 48 to 71 years) were selected. The visual acuity of all subjects was 1.0 or better with the best correction. Contrast sensitivity function (CSF) was measured in four simulated light conditions (daylight, daylight with peripheral glare, twilight, twilight with central glare) by MCT8000 (Vistech). The light scattering intensity of the crystalline lens was measured by EAS-1000 (Nidek).
The TB improved the CSF of the elderly volunteers under daylight conditions and of 1 of the cataract patients under all conditions. In the younger group, the CSF did not change under daylight conditions and deteriorated under twilight conditions. Although the ADR was effective for glare protection in the young volunteers, the protective effects of the TB were better than those of ADR for the middle-aged group.
Sunglasses not only protect against glare but also stabilize visual quality under various light conditions (e.g. passing through a tunnel while driving). Aging changes in lens transparency should be specially considered when developing protective eyewear.
Developments in ophthalmology 02/2002; 35:93-103.
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ABSTRACT: To predict the postoperative anterior chamber (AC) depth from the preoperative in situ position of the lens central clear zone (CCZ) using Scheimpflug slit photography.
111 eyes of 78 cases that underwent phacoemulsification and intraocular lens (IOL) implantation were examined. 748 eyes of 383 healthy subjects with transparent lenses were used as the control. Scheimpflug slit photography was done under maximal mydriasis, and biometry was performed on the photographs. Two types of acrylic IOLs (MA30BA and MA60BM, both from Alcon) were used in this study. The preoperative AC depth (L1), the distance between the anterior lens capsule and lens CCZ (L2) and the postoperative AC depth (I1) were determined. I2, the predicted postoperative AC depth, was then determined from a linear regression of L1 + L2 and I1.
L2 thickened by 0.014 mm/year, and L1 decreased by 0.016 mm/year in the transparent lenses. L1 + L2 changed little with aging in both cataractous and transparent lenses. L1 + L2 and I1 showed a linear correlation with r = 0.80 in the MA30BA and r = 0.77 in the MA60BM groups. The mean error values between I1 and I2 were 0.095 +/- 0.096 and 0.123 +/- 0.114 mm in MA30BA and MA60BM, respectively. The error between I1 and I2 was within +/- 0.17 and +/- 0.33 mm or less in 72.9 and 91.5% of MA30BA and in 82.7 and 96.2% of MA60BM. In contrast, the error between I2 and I1 when calculated using the SRK/T formula was much larger - in excess of +/- 0.33 mm in 38.7% of the eyes.
L1 + L2 changes little with aging and is considered a useful marker of the position of the crystalline lens in situ. There was a high correlation between I1 and L1 + L2. These allow a far more accurate prediction of I1 than previous methods. In combination with the conventional regression formula and ray tracing, a highly accurate IOL power calculation can be attained.
Ophthalmic Research 34(5):265-72. · 1.56 Impact Factor
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ABSTRACT: alpha-Lipoic acid (LA) is well known as a powerful antioxidant. The efficacy of dihydrolipoate-LA for oral administration against streptozotocin (STZ)-induced diabetic cataract in rat was investigated.
Rats were divided into three groups, control, diabetes mellitus (DM), and DM treated with LA (DM+LA). Diabetes was induced by intravenous injection of 50 mg/kg STZ. DM+LA rats were fed 30 mg/rat per day LA in their diet. Lens changes were assessed using Scheimpflug images (EAS-1000) and by measuring light-scattering intensity.
Increase in lens light scattering was less (P < 0.05) in DM+LA rats than in DM rats 5 weeks after induction of diabetes. DM rats had the highest and control rats the lowest blood glucose levels at every measurement point up to 111 days (P < 0.05).
LA treatment delayed development and progression of cataract in rats with streptozotocin-induced diabetes.
Japanese Journal of Ophthalmology 51(1):10-3. · 0.92 Impact Factor
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Yoko Yamashiro,
Akimasa Hirata,
Kenichi Sato,
Masami Kojima,
Taiji Sakai,
Soichi Watanabe,
Kanako Wake,
Masao Taki,
Yukihisa Suzuki,
Yoshitsugu Kamimura, Yasuo Sakamoto,
Yutaka Kawakami,
Kazuyuki Sasaki,
Hiroshi Sasaki
