Discrimination between Surgical and Nonsurgical Nuclear Cataracts Based on ROC Analysis

Analysis of the Dysfunctional Lens Index as a Novel Criterion for Surgical Decision-Making in Age-Related Cataracts

BACKGROUND

The dysfunctional lens index (DLI) provided by a ray-tracing aberrometry system is an objective index in cataract assessment. The purpose of this study is to evaluate correlations among Lens Opacities Classification System III (LOCS III) grades, Catquest 9SF scores, and the (DLI) and the DLI's role in surgical decision-making in age-related mixed cataract.

METHODS

This trial was registered at NIH (clinicaltrial.gov) on January 5, 2021 (NCT04711395). In this prospective cross-sectional study, age-related mixed cataract patients were recruited. One high-volume and two low-volume surgeons made surgical decisions based on corrected distance visual acuity (CDVA), LOCS III graded photographs, and Catquest 9SF scores. Their decision-making agreement was evaluated with Cohen's kappa coefficient. Correlations among the parameters were analyzed. The optimal cut-off DLI was calculated using a receiver operating characteristic curve.

RESULTS

Overall, 106 patients (106 eyes) were included. Very good agreement levels were noted among the high- and low-volume surgeons (Cohen's kappa coefficient, 0.848) (95% CI, 0.748-0.948). The DLI had the strongest correlation with Catquest 9SF scores (R2 = 0.566), followed by with posterior subcapsular (R2 = 0.418), nuclear opalescence (R2 = 0.388), and cortical (R2 = 0.333, all P < .0001) cataract LOCS III grades. Catquest 9SF scores were correlated with cortical (R2 = 0.249), nuclear opalescence (R2 = 0.278), and posterior subcapsular (R2 = 0.235, all P < .0001) cataract LOCS III grades. A cut-off DLI of 5.36 was identified as a surgical criterion (specificity, 86.9%; sensitivity, 93.3%).

CONCLUSIONS

The DLI is valuable for objectively assessing patient complaints and lens opacity severity. LOCS III remains effective and economical in assessing early cortical cataracts with relatively clear central lenses. A cut-off DLI ≤5.36 could be a criterion for preoperative decision-making.

Objective cataract grading methods and expected contrast sensitivity reestablishment with multifocal intraocular lenses

PURPOSE

To determine the cut-off points for age and metrics provided by cataract grading objective systems for which a reestablishment in contrast sensitivity (CS) is expected after multifocal intraocular lens (MIOL) implantation.

METHODS

One hundred seven subjects were included in this retrospective analysis carried out during the screening for presbyopia and cataract surgery. Monocular distance corrected contrast sensitivity defocus curve (CSDC) and visual acuity were measured, and crystalline lens sclerosis was graded with three objective metrics: Ocular Scatter Index (OSI), Dysfunctional Lens Index (DLI) and Pentacam Nucleus Staging (PNS). A CS value of 0.8 logCS at far distance, following published literature on this matter, was selected to compute the cut-off that maximized the detection of eyes exceeding this value at the preoperative screening, either for age or objective metrics.

RESULTS

The CDCS showed a stronger correlation than CDVA with objective grading methods, whereas all objective metrics were significantly correlated between them (p < 0.05). The cut-offs for age, OSI, DLI and PNS were ≤ 62, ≤ 1.25, ≥ 7.67 and ≤ 1, respectively. The OSI provided the highest area under the receiver operating characteristic curve (0.85) followed by the age (0.84), DLI (0.74) and PNS (0.63).

CONCLUSIONS

Surgeons conducting clear lens exchange should communicate the possible distance CS loss after surgery with MIOL implantation according to the previous described cut-offs points. Age in combination with any cataract grading objective system is recommended to detect possible inconsistencies.

Implementation of the Frequency Scatter Index in Clinical Commercially Available Double-pass Systems

A previous work has reported a methodology to quantify intraocular scattering using a high sensitivity double-pass instrument with a robust index, the frequency scatter index. The purpose of our study was to evaluate an adaptation of the frequency scatter index for use in clinical double-pass systems. A prospective observational study was carried out in a group of patients with nuclear cataracts (n = 52) and in a control group (n = 11) using conventional double-pass systems. The frequency scatter index and the objective scatter index were used to assess the scattering. The Spearman coefficient was calculated to assess the correlation between both indexes, obtained from the double-pass images. Simultaneous measurements were performed with a double-pass and with a Hartmann-Shack wavefront sensor in the control group. The root-mean-square wavefront error and the full width at half maximum of the double-pass image were used to quantify the residual aberrations introduced by the variations in pupil size and retinal eccentricity. Measurement in eyes with different grades of cataracts shows a strong correlation (ρ = 0.929, p < .0001) between the frequency scatter index and the objective scatter index. A certain degree of correlation was observed between the objective scatter index and the root-mean-square and between the objective scatter index and the full width at half maximum, both for measurements with a different pupillary diameter and with a different retinal eccentricity (p < .05). No relationship was observed between the frequency scatter index and the root-mean-square or between the frequency scatter index and the full width at half maximum (p > .05). We have introduced and evaluated an adaptation of a methodology proposed recently for the measurement of intraocular scattering using the double-pass technique with a robust index, which is less affected by ocular aberrations. The frequency scatter index can be applied to conventional double-pass instruments available in clinical environments.

Dysfunctional Lens Index Serves as a Novel Surgery Decision-Maker for Age-Related Nuclear Cataracts

Purpose: To study the correlations between subjective and objective cataract metrics with dysfunctional lens index. To investigate the potential of the DLI as a novel surgery decision-maker. Methods: In this prospective, cross-sectional study, we measured the dysfunctional lens index (DLI), Lens Opacities Classification System III nuclear opalescence (LOCS III NO) grading, preoperative corrected distance visual acuity (CDVA), objective scatter index (OSI) and Scheimpflug-based average lens density (ALD) in eyes with nuclear cataract. Eyes were classified as Surgical and Non-Surgical groups. Correlations among the DLI, OSI, ALD, LOCS III NO grading, and preoperative CDVA were analyzed. The receiver operating characteristic (ROC) curve analysis was performed for DLI, OSI, and CDVA to determine optimal cut-off values to separate between surgical and non-surgical cataracts. Results: The DLI showed the strongest correlation with the OSI (r= -0.712, P< .001), followed by LOCS III NO score (r= -0.661, P< .001), ALD (r= -0.596, P< .001) and preoperative CDVA (r= 0.563, P< .001). The area under ROC curves (AUCs) of the DLI, OSI and preoperative CDVA curve were 0.972, 0.912 and 0.844 (All P< .001), respectively. The DLI cut-off value of 5.7 implied higher levels of sensitivity (91.67%) and specificity (91.84%) than the OSI cut-off value of 2.9 and the CDVA cut-off value of 0.55 (sensitivity of 89.58% and 71.92%; specificity of 81.63% and 85.71%, respectively). Conclusion: The surgery criterion of DLI ≤ 5.7 behaved better than the surgery criterions of OSI ≥ 2.9 and preoperative CDVA ≤ 0.55 in discrimination between surgical and non-surgical nuclear cataracts.

Lens nuclear opacity quantitation with long-range swept-source optical coherence tomography: correlation to LOCS III and a Scheimpflug imaging-based grading system

PURPOSE

To quantitate lens nuclear opacity using long-range swept-source optical coherence tomography (SS-OCT) images and to evaluate the correlation of this method to Lens Opacities Classification System III (LOCS III) and a Scheimpflug imaging-based grading system (Pentacam Nuclear Stage function; PNS).

METHODS

This study enrolled 120 participants (120 eyes) with age-related nuclear cataracts. The best-corrected visual acuity (BCVA), LOCS III nuclear opalescence (NO) and nuclear colour (NC) were obtained. The nuclear density measured using PNS function (ND_PNS) was recorded. Three successive series of long-range SS-OCT images were captured, and the nuclear region was analysed using ImageJ (NIH, Bethesda, Maryland, USA) to generate SS-OCT image-based nuclear density (ND_SS-OCT). The repeatability of ND_SS-OCT measurement was evaluated using within-subject coefficient of variation (CV_w) and intraclass correlation coefficient (ICC). Correlations of ND_SS-OCT with NO and NC, BCVA and ND_PNS were analysed. According to the integrity of nucleus imaged by Pentacam, patients were divided into two groups, and the parameters were compared between groups.

RESULTS

The CV_w and ICC for ND_SS-OCT measurement were 1.5 % and 0.994, respectively. The ND_SS-OCT significantly correlated with NO (r=0.831), NC (r=0.873), BCVA (r=0.655) and ND_PNS (r=0.891). The ND_SS-OCT, NO and NC, and BCVA were significantly different between the two groups.

CONCLUSION

Lens nuclear opacity quantitation using long-range SS-OCT images was repeatable and correlated well with LOCS III and PNS function. The Scheimpflug principle had a limitation in imaging dense nucleus. Long-range SS-OCT seems more promising for objectively and quantitatively assessing lens nuclear opacity.

Utility of the optical quality analysis system for decision-making in cataract surgery

BACKGROUND

A cataract is a common cause of vision impairment that requires surgery in older subjects. The Optical Quality Analysis System (OQAS, Visiometrics SL, Terrassa, Spain) assesses the optical quality of the eye in cataract patients. This study shows the role of the optical quality evaluation system for decision-making in cataract surgery. We investigated the clinical utility of the OQAS for decision-making in cataract surgery.

METHODS

Sixty-seven eyes from 67 patients undergoing cataract surgery and 109 eyes from 109 control subjects were compared. The best corrected visual acuity (BCVA) was measured. The objective scatter index (OSI), modulation transfer function (MTF), Strehl ratio, predicted visual acuity (PVA) 100%, PVA 20%, and PVA 10% were measured using the OQAS. The sensitivity and specificity of the different parameters were analyzed using the receiver operating characteristic (ROC) curve. The main parameters measured were sensitivity and specificity.

RESULTS

The BCVA, OSI, PVA 100%, PVA 20%, and PVA 10% were higher in the cataract group compared to those in the control group, while the MTF and Strehl ratios were lower (p <  0.001 for all). ROC analysis showed that the OSI had the largest area under the curve and that the sensitivity and specificity of the OSI were 83.9 and 84.6%, respectively, at the optimal cut-off point of 2.35.

CONCLUSION

The MTF, OSI, Strehl ratio, PVA 100%, PVA 20% and PVA 10% may be useful parameters for preoperative decision-making in cataract surgery. The OSI appears to be the most effective parameter for this purpose.

From Presbyopia to Cataracts: A Critical Review on Dysfunctional Lens Syndrome

Dysfunctional lens syndrome (DLS) is a term coined to describe the natural aging changes in the crystalline lens. Different alterations in the refractive properties and transparency of the lens are produced during the development of presbyopia and cataract, such as changes in internal high order aberrations or an increase in ocular forward scattering, with a potentially significant impact on clinical measures, including visual acuity and contrast sensitivity. Objective technologies have emerged to solve the limits of current methods for the grading of the lens aging, which have been linked to the DLS term. However, there is still not a gold standard or evidence-based clinical guidelines around these new technologies despite multiple research studies have correlated their results with conventional methods such as visual acuity or the lens opacification system (LOCS), with more scientific background around the ocular scattering index (OSI) and Scheimpflug densitometry. In either case, DLS is not a new evidence-based concept that leads to new knowledge about crystalline lens aging but it is a nomenclature change of two existing terms, presbyopia and cataracts. Therefore, this term should be used with caution in the scientific peer-reviewed literature.

Effects of aging on optical quality and visual function

BACKGROUND

We assessed the effects of aging on visual function and optical quality in a healthy adult population and provide reference values for different age ranges.

METHODS

We conducted a prospective study with 198 healthy volunteers from 31 to 70 years of age. The visual acuity (VA) and contrast sensitivity (CS) at 3, 6, 12 and 18 cycles per degree (cpd) frequencies were assessed, together with values of optical quality and intraocular scattering obtained with a double-pass system (Optical Quality Analysis System - OQAS), specifically the modulation transfer function cutoff frequency (MTF_cutoff ), the Strehl ratio, the OQAS values (OV) at contrasts of 100, 20 and nine per cent and the objective scatter index (OSI). We studied the change of these variables with age and obtained standard values for optical quality and intraocular scattering parameters for four age groups: 31 to 40, 41 to 50, 51 to 60 and 61 to 70 years.

RESULTS

We found significant correlations between age and all variables analysed and significant differences among the age groups considered except for CS (3 cpd) (p = 0.067). Ageing particularly affected low-contrast parameters, such as the OV nine per cent and the OSI, which decreased to 37 and 50 per cent of their original values, respectively. The OSI was found to provide high sensitivity and specificity values, when healthy and caratactous eyes were considered. The results suggest that optical deficits are compensated until 50 years of age with sensory and perceptual factors, as smaller changes were found for visual function than for objective measurements of optical quality and intraocular scattering.

CONCLUSIONS

Measures of optical quality assessed by subjective psychophysical and objective techniques varied differently with age. Values obtained for each age group can be used to determine normal limits of optical quality and intraocular scattering for diagnosis of ocular conditions.