Comparison of Different Measurement Tools and Dimensional Parameters of Pterygium to Investigate its Impact on Refractive Indices and Ocular Aberrations

Gümüş, Koray; Güven, Ayşegül; Altınkaynak, Miray; Keskin, Merve

doi:10.1097/icl.0000000000000309

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Several studies have established a relationship between the size of the pterygium and corneal astigmatism 14 , 15 . Mohammad-Salih and Sharif 14 reported that the total area, extension, and width of the pterygium showed a strong correlation with the magnitude of corneal astigmatism measured by keratometry.…”

Section: Discussionmentioning

confidence: 99%

Effect of pterygium on corneal astigmatism, irregularity and higher-order aberrations: a comparative study with normal fellow eyes

Yoon

Seol

Choi

2023

Sci Rep

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Pterygium is an abnormal growth of fibrous conjunctival tissue that invades the cornea, resulting in corneal distortion, astigmatism, and increased higher-order aberrations (HOAs). However, few studies have compared eyes with pterygium to normal fellow eyes when interpreting HOAs and there is no study that revealed the effect of the thickness or grading of the pterygium on the change of HOAs. Therefore, we evaluated the effects of nasal pterygium by comparing the normal fellow eye of 59 patients. The pterygium significantly increased with-the-rule corneal astigmatism and corneal irregularity. Trefoils, horizontal coma, and quatrefoils were significantly induced by the pterygium. The grading of the pterygium was not correlated with its characteristics except for the thickness. In multiple linear regression analysis, pterygium-induced corneal astigmatic/irregularity values and horizontal trefoil/quatrefoil were associated with the area of the pterygium. The length of the pterygium was an independent inducer of oblique trefoil/quatrefoil, while horizontal coma was independently associated with both its length and width. The thickness was not correlated with any optical parameters. Together, the results demonstrate that nasal pterygium significantly induces corneal astigmatism, irregularity and some HOAs. These pterygium-associated changes in optical parameters could be predicted by the length, width and area of the pterygium.

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Section: Discussionmentioning

confidence: 99%

Effect of pterygium on corneal astigmatism, irregularity and higher-order aberrations: a comparative study with normal fellow eyes

Yoon

Seol

Choi

2023

Sci Rep

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“…34 Fourth, it should be noted that the ground truth of referable pterygium was defined based on the presence of pterygium with >2.50 mm extension towards the cornea or with a base width of >5.00 mm, but did not take total area and fleshiness (ie, thickness) 20 of the pterygium into account. However, previous studies have indicated that horizontal extension along with the base width of the pterygium [23][24][25][26] have the greatest influence on corneal astigmatism and ocular aberrations. Thus, the omission of total area and fleshiness from our definition criteria, unlikely had major bearing on our findings.…”

Section: Discussionmentioning

confidence: 99%

“…[22][23][24] In addition, previous study also showed that medium-sized pterygium (defined as extension onto the cornea with length between 2.03.5 mm and vertical length between 5.1 and 7.0 mm) also had higher ocular aberrations compared with small-sized pterygium (with encroachment of <2.00 mm in length or base width <5.00 mm). 25 26 Building on from these previous findings, we further defined referable pterygium in our study, by using more stringent criteria of >2.50 mm encroachment onto the cornea (measured from the limbus) or base width (at limbus) of >5.00 mm. The size of pterygium was measured using the slit lamp's measurement graticule.…”

Section: Definitions Of Pterygium and Referable Pterygiummentioning

confidence: 99%

Deep learning algorithms for automatic detection of pterygium using anterior segment photographs from slit-lamp and hand-held cameras

et al. 2021

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Background/aimsTo evaluate the performances of deep learning (DL) algorithms for detection of presence and extent pterygium, based on colour anterior segment photographs (ASPs) taken from slit-lamp and hand-held cameras.MethodsReferable pterygium was defined as having extension towards the cornea from the limbus of >2.50 mm or base width at the limbus of >5.00 mm. 2503 images from the Singapore Epidemiology of Eye Diseases (SEED) study were used as the development set. Algorithms were validated on an internal set from the SEED cohort (629 images (55.3% pterygium, 8.4% referable pterygium)), and tested on two external clinic-based sets (set 1 with 2610 images (2.8% pterygium, 0.7% referable pterygium, from slit-lamp ASP); and set 2 with 3701 images, 2.5% pterygium, 0.9% referable pterygium, from hand-held ASP).ResultsThe algorithm’s area under the receiver operating characteristic curve (AUROC) for detection of any pterygium was 99.5%(sensitivity=98.6%; specificity=99.0%) in internal test set, 99.1% (sensitivity=95.9%, specificity=98.5%) in external test set 1 and 99.7% (sensitivity=100.0%; specificity=88.3%) in external test set 2. For referable pterygium, the algorithm’s AUROC was 98.5% (sensitivity=94.0%; specificity=95.3%) in internal test set, 99.7% (sensitivity=87.2%; specificity=99.4%) in external set 1 and 99.0% (sensitivity=94.3%; specificity=98.0%) in external set 2.ConclusionDL algorithms based on ASPs can detect presence of and referable-level pterygium with optimal sensitivity and specificity. These algorithms, particularly if used with a handheld camera, may potentially be used as a simple screening tool for detection of referable pterygium. Further validation in community setting is warranted.Synopsis/precisDL algorithms based on ASPs can detect presence of and referable-level pterygium optimally, and may be used as a simple screening tool for the detection of referable pterygium in community screenings.

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“…So far, there were only few researches studying the effect of pterygium on back corneal indices and corneal aberrations. [9][10][11] To evaluate the changes in visual function caused by pterygium, ambient illumination levels has to be studied. Low ambient illumination means larger pupil diameter than that in natural-light condition.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Pterygium on Front and Back Corneal Astigmatism and Aberrations in Natural-Light and Low-Light Conditions

xu,

2023

Preprint

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Background To investigate the effect of different sizes of pteryium on the front and back corneal topography, corneal refractive changes and aberrations in natural-light and low-light conditions. Methods Sixty subjects with unilateral primary nasal pterygium were enrolled in this study. All the patients’ uncorrected, best spectacle-corrected visual acuities, corneal topographic aberration data in 3mm and 7mm areas were collected. The pterygia sizes were evaluated by the slit-lamp photography and Sirius Scheimpflug Analyzer. Results The front topographic astigmatism values, corneal total abbertions, and higher-order aberrations in 3mm and 7mm areas were higher in the pterygia group than those in the control group. The ptergia horizontal length and thickness were moderately to strongly correlated with astigmatism and RMS of aberrations, while pterygia vertical length showed no or just mild correlation with the cornCompared to the readings in 3mm area, the front and back corneal astigmatism and aberrations were larger in 7mm area. Conclusions Pterygia led to visual impairment by inducing astigmatism and aberrations. In low-light condition, the visual function were worse because of increased corneal astigmatism values and aberrations.

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Comparison of Different Measurement Tools and Dimensional Parameters of Pterygium to Investigate its Impact on Refractive Indices and Ocular Aberrations

Cited by 5 publications

References 15 publications

Effect of pterygium on corneal astigmatism, irregularity and higher-order aberrations: a comparative study with normal fellow eyes

Effect of pterygium on corneal astigmatism, irregularity and higher-order aberrations: a comparative study with normal fellow eyes

Deep learning algorithms for automatic detection of pterygium using anterior segment photographs from slit-lamp and hand-held cameras

The Effect of Pterygium on Front and Back Corneal Astigmatism and Aberrations in Natural-Light and Low-Light Conditions

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