Normative Database for Corneal Backscatter Analysis by In Vivo Confocal Microscopy

Hillenaar, Toine; Cals, Roger H H; Eilers, Paul H.C.; Wubbels, René J.; Cleynenbreugel, Hugo Van; Remeijer, Lies

doi:10.1167/iovs.11-7747

Cited by 55 publications

(46 citation statements)

References 26 publications

(33 reference statements)

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“…Previously, some literatures [2,15] reported significantly increase of corneal density with age and some reported contradictory findings [4,16,17]. However, this study observed a significant increase in corneal density of about 2-3 GSU with each increment of a decade of age.…”

Section: Discussioncontrasting

confidence: 62%

Normal Values of Corneal Optical Densitometry Using Pentacam Scheimpflug Camera

Asrar¹,

Ikram²,

Khan³

et al. 2016

AOVS

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Purpose: The purpose of the study was to illustrate the range of normal values of corneal densitometry using Pentacam Scheimpflug camera. Methodology:Prospective study was conducted at tertiary care Amanat eye hospital. 490 eyes of 490 participants of different age groups were added. All scans were performed in diagnostics room with uniform ambient light, performed by trained ophthalmic technologist. All participants were Pakistani of different ethnic groups. Only one eye of each participant was included to control biasness. T test, One-way ANOVA, pearson correlation coefficient and linear regression model tests were applied for analysis.Results: 490 eyes; 247 right eyes and 243 left eyes were analyzed. Mean age was 41.7±15.27 years (range 20-81 years) with 48.4% male and 51.6% females. based on corneal depth; highest backward scattering of light was observed in anterior (120 µm) layer (20.6±8.52 GSU) than central and posterior layers 13.6±5.17 GSU and 11.7±3.99 GSU respectively. The difference was statistically significant among layers with p< 0.001. Based on corneal surface, minimum backscattering was noted in central 0-6mm zone which increases from central to limbal zone; 0-2mm zone was 13.2±3.81 GSU, 2-6mm zone was 12.6±3.68 GSU, 6-10mm zone was 16.0±8.90 GSU and 10-12mm zone was 22.1±8.26 GSU. The difference was statistically significant with p<0.001. Significant correlation of corneal densitometry and age was observed r= 0.677, p<0.001. Conclusion:Objective assessment of corneal densitometry can be made with Pentacam Scheimpflug. Normative values of corneal density may be used in routine clinical practice and provided a reference for future research.

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Section: Discussioncontrasting

confidence: 62%

Normal Values of Corneal Optical Densitometry Using Pentacam Scheimpflug Camera

Asrar¹,

Ikram²,

Khan³

et al. 2016

AOVS

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“…7 While we attempted to age-match our subjects with Fuchs dystrophy and normal corneas, the mean age of the normal group was younger. Despite this limitation, increasing age is minimally associated with increased corneal backscatter, 32 and the 4% per decade decrease in stromal cells 33 would not explain the magnitude of the cell loss in this study. The stromal cell densities reported in this study appear lower than those in our previous study 12 because unlike the previous study, we were unable to correct the densities for the effect of corneal edema (surgical intervention was performed in the previous study which enabled measurement of postoperative host stromal thickness).…”

Section: Discussionmentioning

confidence: 62%

Corneal Abnormalities Early in the Course of Fuchs' Endothelial Dystrophy

et al. 2014

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Purpose Corneas with advanced Fuchs endothelial dystrophy that require endothelial keratoplasty manifest anterior corneal structural and cellular abnormalities that have been associated with visual deficits both before and after endothelial keratoplasty. In this study, we determined the onset of these abnormalities in the course of the disease. Design Cross-sectional study. Participants Sixty-three eyes (39 subjects) with a range of severity of Fuchs dystrophy, and 25 eyes (13 subjects) with normal corneas. Methods All corneas were examined by using slit-lamp biomicroscopy, ultrasonic pachymetry, and confocal microscopy. The clinical grade of Fuchs dystrophy was assessed according to the presence and extent of guttae and clinically evident edema, and was categorized as mild (grades 1–2), moderate (grades 3–4), or advanced (grades 5–6). Normal corneas were devoid of any central guttae (grade 0). Corneal backscatter (haze) was measured from the confocal image light intensity profile. Stromal cell density and number, and the presence of abnormal subepithelial cells, were determined from confocal images. Comparisons between groups were made by using generalized estimating equation models to account for any correlation between fellow eyes of the same subject. Main Outcome Measures Anterior corneal backscatter, stromal cell density and number, presence of subepithelial cells, central corneal thickness. Results Anterior corneal backscatter was 18–67% higher in moderate and advanced Fuchs dystrophy compared to normal (p≤0.003); a similar trend was noted in mild Fuchs dystrophy compared to normal (p=0.08). Stromal cell density and the absolute number of stromal cells in the anterior 10% of the stroma were approximately 20% and 27% lower, respectively, in Fuchs dystrophy (regardless of severity) compared to normal (p<0.001). Abnormal subepithelial cells were visible in 9%, 19%, and 30% of corneas with mild, moderate, and advanced Fuchs dystrophy, respectively. Only corneas with advanced Fuchs dystrophy were thicker than normal (p<0.001). Conclusions Anterior corneal cellular and structural abnormalities begin early in the course of Fuchs dystrophy, prior to the onset of clinically evident edema. The chronicity of these changes can explain their incomplete resolution after endothelial keratoplasty, and understanding the onset of these might help to determine the optimal time to intervene to achieve best outcomes.

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“…Other methods of evaluating corneal transparency are optical coherence tomography (OCT) [22] and in vivo confocal microscopy (IVCM) [23]. …”

Section: Discussionmentioning

confidence: 99%

Corneal Clarity and Visual Outcomes after Small-Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted In Situ Keratomileusis

Lazaridis

Droutsas

Sekundo

et al. 2017

Journal of Ophthalmology

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Purpose. To evaluate corneal clarity and visual outcomes after small-incision lenticule extraction (SMILE) and compare them to femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Materials and Methods. Fifty-eight myopic eyes of 33 patients who underwent SMILE were compared to 58 eyes of 33 patients treated with FS-LASIK. All procedures were performed using VisuMax® femtosecond laser and MEL 80® excimer laser (Carl Zeiss Meditec AG, Germany). Pentacam™ (Oculus, Germany) was used for pre- and 3-month postoperative corneal densitometry (CD) analysis. CD was evaluated at 3 optically relevant, concentric radial zones (0–2 mm, 2–6 mm, and 0–6 mm annulus) around the corneal apex and at 3 different anatomical corneal layers (anterior, central, and posterior). Associations of postoperative CD values with the lenticule thickness and ablation depth were examined. Preoperative and postoperative corrected distance visual acuity (CDVA) values were also compared. Results. After SMILE, the total CD (all corneal layers) at 0–6 mm annulus showed no significant change compared to preoperative values (P = 0.259). After FS-LASIK, the total CD was significantly reduced (P = 0.033). Three-month postoperative CD showed no significant differences between the 2 groups for all examined annuli (0–2 mm: P = 0.569; 2–6 mm: P = 0.055; and 0–6 mm: P = 0.686). Total CD after SMILE at 0–6 mm annulus displayed a weak negative association with the lenticule thickness (P = 0.079, R2 = 0.0532) and after FS-LASIK displayed a weak negative association with the ablation depth (P = 0.731, R2 = 0.0015). Postoperative CDVA was similar for both groups (P = 0.517). Conclusion. Quantification of corneal clarity using the Scheimpflug CD showed similar results before and 3 months after SMILE. Compared to FS-LASIK, no significant differences of corneal clarity and CDVA were found 3 months postoperatively.

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Normative Database for Corneal Backscatter Analysis by In Vivo Confocal Microscopy

Cited by 55 publications

References 26 publications

Normal Values of Corneal Optical Densitometry Using Pentacam Scheimpflug Camera

Normal Values of Corneal Optical Densitometry Using Pentacam Scheimpflug Camera

Corneal Abnormalities Early in the Course of Fuchs' Endothelial Dystrophy

Corneal Clarity and Visual Outcomes after Small-Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted In Situ Keratomileusis

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