An Index for Human Lens Transparency Related to Age and Lens Layer: Comparison between Normal Volunteers and Diabetic Patients with Still Clear Lenses

Sekiya, Hiroshi; Hockwin, O.; Kasuga, Takabumi; Nagai, Kouta; Sakamoto, Y.; Sasaki, Kohsuke

doi:10.1159/000055519

Cited by 27 publications

(23 citation statements)

References 11 publications

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“…Diabetics are known to have thicker lenses. [6][7][8]16 Therefore, to remove the confounding effect of diabetes on lens thickness, diabetics were excluded. Peripheral cortical spokes can be missed in the non-dilated pupil.…”

Section: Discussionmentioning

confidence: 99%

“…3 The thickness of the human lens has been found to be related to age, sex, cataract type, and diabetic status. [4][5][6][7][8][9] The primary objective of our observational study was to compare lens thickness measurements in eyes with a clear lens to eyes with different types of isolated cataract (nuclear, cortical, and posterior subcapsular (PSC)); the influence of age groups and axial length (AL) categories on lens thickness; and the impact of lens thickness on anterior chamber depth (ACD) in individuals with cataract and clear lens.…”

Section: Introductionmentioning

confidence: 99%

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Lens thickness of Indian eyes: impact of isolated lens opacity, age, axial length, and influence on anterior chamber depth

Praveen

Vasavada

Shah

et al. 2008

Eye

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Purpose To report relationship of age group and axial length (AL) category to lens thickness values in eyes with a clear lens or different types of isolated cataract (nuclear, cortical, and posterior subcapsular (PSC)). Further, we evaluated lens thickness values on anterior chamber depth (ACD) in these eyes. Design Observational clinic-based study. Methods An observational study of 1442 eyes of 1442 individuals (816 eyes with isolated cataract and 626 eyes with clear lens) of those above 25 years of age was evaluated. AL and lens thickness were performed with an A-scan ultrasound after dilatation of the pupil, and manual optical pachymetry was used to measure ACD after dilatation of the pupil. Main outcome measures: Lens thickness. Results Multiple regression analysis revealed that with each decade of advancement in age, the lens thickness increased by 0.155 mm (Po0.001). The difference in lens thickness after adjusting for age group and AL category was less in cortical cataract by À0.25 mm (Po0.001) and PSC by À0.29 mm (Po0.001); With advancement in AL category, lens thickness decreased by 0.004 mm (Po0.001). After adjusting for all the parameters/variables, regression analysis revealed that as lens thickness increased, there was a significant decrease in ACD (mean À0.44 mm; Po0.001). Conclusions Lens thickness was significantly greater in clear lenses when compared with isolated cataractsFgreatest with nuclear cataract and least with PSC. Age group and AL category had a significant impact on the lens thickness of both cataract and clear lens. A significant decrease in ACD was found with the increase in lens thickness.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lens thickness of Indian eyes: impact of isolated lens opacity, age, axial length, and influence on anterior chamber depth

Praveen

Vasavada

Shah

et al. 2008

Eye

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“…However, an older lens has a greater tendency to scatter light, even if it is clear. 21 This could affect the test results when using reduced stimulus luminance.…”

Section: Discussionmentioning

confidence: 99%

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Nilsson¹,

Wanger²,

Martin³

2006

Clinical and Experimental Optometry

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Recently, the Rarebit Fovea Test (RFT) was developed with the explicit aim of improving detection of low-degree neural damage. 4,5 It relies on very small bright dots of light, briefly shown against a dark background and subtending a visual angle of approximately 0.5 minutes of arc. Thus, the retinal image of the dot is small compared to receptive field size. 4 The results from the RFT are presented as mean hit rates, that is, the proportion of perceived dots expressed as a percentage of all presented dots. In a previous study, the median of the mean hit rates, obtained from normal subjects, was 100 per cent (range 97 to 100) in the age group below 65 years and 87.5 per cent (range 34 to 98) in subjects older than 65 years.5 These results indicate a 'ceiling effect', that is, the Background: Conventional visual tests are not sensitive enough to detect low degree neural damage, as 6/6 (1.0) visual acuity can be upheld with less than two-thirds of the normal number of optic nerve axons. The aim of the current study was to evaluate the physiologic properties of a new computerised test, the Rarebit Fovea Test (RFT), using very small stimuli, by quantifying the effect of age and binocular summation in relation to stimulus luminance. Methods: The RFT relies on the perception of very small (less than 0.5 minutes of arc) bright stimuli. Two different experiments were performed. 1. Thirty-five subjects (age 19 to 63 years) were tested with five different stimulus luminances, 158, 64, 53, 41 and 33 cd/m 2 . 2. Nineteen subjects (age 19 to 63 years) were tested using binocular stimulation to define the binocular summation. Results: Significantly reduced median hit rates were observed at luminances of 53 cd/m 2 or below. Age and mean hit rate correlated negatively at all luminance levels below 158 cd/m 2 . The mean hit rate from binocular stimulation, compared to the highest value from monocular stimulation in the same subject, was increased by a factor of 1.54 ± 0.45 (SD). No age effect was found regarding binocular summation. Conclusions:The results in the current study indicate that RFT can identify some of the well-known features of the visual system, that is, the effects of age and binocular summation, provided that the stimulus luminance is adequately selected.

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“…Our previous study has already shown a very high correlation (r = 0.91) between L2 and the full lens thickness [12]. eyes.…”

Section: Resultsmentioning

confidence: 72%

“…The correlation is quite good with r = 0.91 [12]. It is possible to substitute L2 for full lens thickness at least in the transparent crystalline lens.…”

Section: Discussionmentioning

confidence: 86%

Predicting Postoperative Anterior Chamber Depth in Cataract Patients Using Scheimpflug Slit Photography

Sekiya

Sakamoto²,

Harada³

et al. 2002

Ophthalmic Res

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Purpose: 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. Methods: 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. Results: 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. Conclusions: 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.

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An Index for Human Lens Transparency Related to Age and Lens Layer: Comparison between Normal Volunteers and Diabetic Patients with Still Clear Lenses

Cited by 27 publications

References 11 publications

Lens thickness of Indian eyes: impact of isolated lens opacity, age, axial length, and influence on anterior chamber depth

Lens thickness of Indian eyes: impact of isolated lens opacity, age, axial length, and influence on anterior chamber depth

Perception of very small visual stimuli in the fovea: normative data for the Rarebit Foveal Test

Predicting Postoperative Anterior Chamber Depth in Cataract Patients Using Scheimpflug Slit Photography

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