Correlation of Nuclear Cataract Lens Density Using Scheimpflug Images with Lens Opacities Classification System III and Visual Function

doi:10.1016/j.ophtha.2009.03.002

Ophthalmology

Volume 116, Issue 8, August 2009, Pages 1436-1443

Presented in part at: the American Academy of Ophthalmology Annual Meeting, New Orleans, LA, November 2007.

https://doi.org/10.1016/j.ophtha.2009.03.002 Get rights and content

Purpose

To calculate the average lens density (ALD) and nuclear lens density (NLD) using Scheimpflug images and to determine their correlation with logarithmic minimal angle resolution (logMAR) best-corrected visual acuity (BCVA), contrast sensitivity (CS), and lens grading based on the Lens Opacities Classification System (LOCS) III.

Design

Cross-sectional observational study.

Participants

One hundred ten patients with age-related nuclear cataract.

Methods

The logMAR BCVA was recorded using Early Treatment Diabetic Retinopathy Study charts and photopic contrast-sensitivity using CSV-1000LV (Vector Vision, Greeneville, OH). Fifty Scheimpflug images (Pentacam, Oculus, Germany) covering 360° of the lens were obtained for 1 eye of each patient after dilation. All Scheimpflug images were exported to ImageJ software (NIH, Bethesda, MD) for analysis wherein the ALD and NLD (using a mask applied to the lens nuclear area) were calculated in pixel-intensity units. Repeatability was determined using coefficient of variation (CoV) and intraclass correlation coefficient (ICC). Lens opacity on slit-lamp images was graded using LOCS III for nuclear opalescence (NO) and nuclear color (NC).

Main Outcome Measures

We evaluated ALD and NLD on Scheimpflug images and their correlation with NO and NC LOCS III grading, BCVA, and photopic CS.

Results

The ICC for ALD and NLD were 0.983 and 0.99, respectively; the CoV were 3.92±1.76% and 2.57±0.74%, respectively. The ALD correlated with NO (r = .774; P<0.001), NC (r = .732; P<0.001), BCVA (r = 0.696; P<0.001), and CS at 3 cycles per degree CPD (P = 0.011), 6, 12, and 18 CPD (P<0.001). The NLD correlated with NO (r = .859; P<0.001), NC (r = .81; P<0.001), BCVA (r = .760; P<0.001), CS at 3 CPD (P = 0.002), 6, 12, and 18 CPD (P<0.001). The NLD had a significantly stronger correlation with BCVA (P<0.05), NO (P<0.01), NC (P<0.01), and CS at 6 CPD (P<0.01) and 12 CPD (P<0.005) compared with ALD.

Conclusions

Repeatable 360° lens density measurements were obtained using Scheimpflug imaging. A stronger correlation was observed between NLD and LOCS III grading, BCVA, and photopic CS than with ALD. The NLD is an objective and repeatable method for assessment of lens density, which could be helpful in longitudinal studies monitoring nuclear cataracts.

Financial Disclosure(s)

The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Section snippets

Patients and Methods

One hundred ten patients with nuclear cataract, diagnosed on slit-lamp examination, were enrolled. Subjects were recruited between May 2007 and March 2008 at the Grewal Eye Institute, Chandigarh, India. None of the patients had had any previous ocular surgery, laser treatments, or a history of any ocular disease other than age-related cataract. All patients underwent slit-lamp examination and dilated fundus examination. Institutional Review Board approval was obtained and the study was

Results

A total of 110 participants were enrolled. Their mean age was 67.1±9.8 years (range, 40–84). The study population was composed of 60 females and 50 males. The mean BCVA was 0.13±0.11 (range, 0–0.4). The mean NO score calculated using LOCS III was 3.73±1.49 (range, 1–6.4) and the mean NC grading was 3.82±1.37 (range, 1.3–6.4). The mean average lens density obtained using ImageJ software (measured in pixel intensity units) was 63.58±20.83 (range, 36.6–110.5) and the mean nuclear lens density

Discussion

The lack of objective measurements of lens opacity is an impediment to clinical trials and studies on cataract formation and growth.³⁵ A standardized grading system for cataracts is needed to accurately reflect the severity of cataract at past appointments, because patients are often seen by a different doctor at each visit. This would be especially useful in longitudinal studies on nuclear cataract. Pei et al²² in a similar study recently reported that the lens density assessed on Pentacam

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Citation Excerpt :
It is also limited in cases of severe nuclear cataract.9 Despite those limitations, it is well correlated to clinical nuclear opalescence, visual acuity, and contrast sensitivity.2,3,14 It should be noted that results are probably more affected thant SS-OCT in cases of corneal diseases given the shorter wavelength used.
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In the validsation set, mean CF was 0.024 ± 0.077 and 0.479 ± 0.230 (p < 0.001). ROC AUC was 0.98 with an optimal CF threshold of 0.14. Using that threshold, sensitivity and specificity to detect cataract were 94.4% and 94.7%, respectively.
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: Manuscript no. 2008-1481.

: Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

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Original articleCorrelation of Nuclear Cataract Lens Density Using Scheimpflug Images with Lens Opacities Classification System III and Visual Function

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Financial Disclosure(s)

Section snippets

Patients and Methods

Results

Discussion

J Cataract Refract Surg

J Cataract Refract Surg

Surv Ophthalmol

Vision Res

J Cataract Refrac Surg

J Cataract Refract Surg

The World Health Organization's programme for the prevention of blindness

Int Ophthalmol

A rapid method of grading cataract in epidemiological studies and eye surveys

Br J Ophthalmol

Smoking cessation and risk of age-related cataract in men

JAMA

Quantitative evaluation of nuclear cataract using image analysis

Ophthalmic Res

The effect of cataract severity and morphology on the reliability of the Lens Opacities Classification System II (LOCS II)

Invest Ophthalmol Vis Sci

The Lens Opacities Classification System III

Arch Ophthalmol

The Age-Related Eye Disease Study (AREDS) system for classifying cataracts from photographs: AREDS report no. 4

Am J Ophthalmol

Grading nuclear cataract: reproducibility and validity of a new method

Br J Ophthalmol

LOCS III examination at the slit lamp, do settings matter?

Ophthalmic Epidemiol

An advanced slit-image camera

Br J Ophthalmol

Quantitative slit-image photography of the lens

Trans Ophthalmol Soc U K

Photographic documentation of disturbances of the lens transparency during ageing with a Scheimpflug camera system

Ophthalmic Res

Methods for evaluation of lens changes

Int Ophthalmol

Measurements of lens transparency or its disturbances by densitometric image analysis of Scheimpflug photographs

Graefes Arch Clin Exp Ophthalmol

Aging studies on normal lens using the Scheimpflug slit-lamp camera

Invest Ophthalmol Vis Sci

Reproducibility study on the Scheimpflug Cataract Video Camera

Curr Eye Res

Original article
Correlation of Nuclear Cataract Lens Density Using Scheimpflug Images with Lens Opacities Classification System III and Visual Function