Dataset Information

The effect of pterygium on front and back corneal astigmatism and aberrations in natural-light and low-light conditions.

ABSTRACT:

Background

To investigate the effect of different sizes of pterygium on the front and back corneal topography, 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 acuity, corneal topographic aberration data in 3 mm and 7 mm areas were collected. The pterygium size was evaluated by the slit-lamp photography and Sirius Scheimpflug Analyzer.

Results

The front topographic astigmatism values, corneal total aberrations, and higher-order aberrations in 3 mm and 7 mm areas were higher in the pterygium group than those in the control group. The pterygium horizontal length and thickness were moderately to strongly correlated with astigmatism and RMS of aberrations, while pterygium vertical length showed no or just mild correlation with the corneal astigmatism and aberrations. Compared to the readings in 3 mm area, the front and back corneal astigmatism and aberrations were larger in 7 mm area.

Conclusions

Pterygium led to visual impairment by inducing astigmatism and aberrations. In low-light condition, the visual function worsened due to increased corneal astigmatism values and aberrations.

SUBMITTER: Xu W

PROVIDER: S-EPMC10768295 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The effect of pterygium on front and back corneal astigmatism and aberrations in natural-light and low-light conditions.

Xu Weiwei W Li Xia X

BMC ophthalmology 20240104 1

<h4>Background</h4>To investigate the effect of different sizes of pterygium on the front and back corneal topography, refractive changes and aberrations in natural-light and low-light conditions.<h4>Methods</h4>Sixty subjects with unilateral primary nasal pterygium were enrolled in this study. All the patients' uncorrected, best spectacle-corrected visual acuity, corneal topographic aberration data in 3 mm and 7 mm areas were collected. The pterygium size was evaluated by the slit-lamp photogra ...[more]

PMID: 38178053

Similar Datasets

Project description:IntroductionPterygium is a benign conjunctival fibrovascular neoformation progressively encroaching on the cornea, it can cause corneal distortion and induce astigmatism, or aggravate pre-existing physiological astigmatism, which is defined as ≤ 0.50 D and not requiring optical correction. The radical treatment of pterygium is purely surgical, with conjunctivo-limbal grafting and conjunctival autografting emerging as the surgical techniques of choice. The main objective of the study was to investigate whether pterygium surgery does not worsen the preoperative physiological astigmatism.Material and methodsThis is a prospective cohort study conducted in the ophthalmology department of the Mohammed V Military Hospital in Rabat over a period of 12 months, including 43 stage II/III/IV pterygia that were operated on by conjunctival autograft by the same surgeon. First, we looked for an association between pterygium surgery and variations in astigmatism. For quantitative variables we used the Wilcoxon test. In a second step we split the file into two distinct groups according to the value of preoperative astigmatism≤ 0.5 D or >0.5 D in order to detect the impact of pterygium surgery on physiological astigmatism. Statistical analysis of the data was performed by comparing the distribution of these characteristics.ResultsThe median astigmatism was 1 D (0.25; 2.50). 35% of our population had preoperative astigmatism ≤0.5 D. The Wilcoxon test showed that there was a statistically significant difference between preoperative and postoperative astigmatism (p = 0.001). The paired sample T-test showed no statistically significant difference between the preoperative and postoperative outcome in the physiological astigmatism population (p = 0.53).ConclusionMany studies have shown the benefits of pterygium excision on astigmatism, but few studies have specified the impact of this surgery on physiological astigmatism. Our study showed that pterygium surgery does not alter physiological astigmatism.

Project description:ObjectivesTo review the pattern of primary pterygium-induced corneal astigmatism in patients with cataract in a southern Chinese population.DesignClinic-based cross-sectional retrospective study.SettingA secondary hospital at southern China.ParticipantsA group of 1689 eyes with primary pterygium (PT group) and the other group of 4062 eyes without pterygium (NPT group) were included.Main outcome measuresCorneal power was measured by an autokeratorefractometer. Corneal astigmatism was calculated as the difference in corneal power between the steepest and flattest meridians. Distribution of corneal astigmatism was compared between eyes with pterygium and eyes without pterygium.ResultsDistribution of corneal astigmatism was different between PT group (skewness=2.548, kurtosis=8.237) and NPT group (skewness=2.778, kurtosis=15.52). Mean corneal astigmatism was significantly higher in the PT group (1.62±1.49D) compared with the NPT group (1.17±0.89D, p<0.0001). The prevalence of corneal astigmatism >1D (PT 52.3%, NPT 40.9%, p<0.0001), >2D (PT 22.4%, NPT 10.6%, p<0.0001) or >3D (PT 10.5%, NPT 3.2%, p<0.0001) was significantly higher in the PT group compared with the NPT group. Eyes in the PT group had significantly higher corneal astigmatism than the NPT group in almost every age group (all p<0.05), with the exception of patients ≥90 years. Moreover, eyes in the PT group had significantly higher with-the-rule (PT 1.72±1.59D, NPT 1.19±0.88D, p<0.0001) and against-the-rule (PT 1.63±1.46D, NPT 1.18±0.88D, p<0.0001) but similar oblique astigmatism (PT 1.11±1.00D, NPT 0.99±0.89D, p=0.065) corneal astigmatism compared with the NPT group. Power vector analysis indicated that the axis of corneal astigmatism was not significantly different between the two groups (J0, PT -0.01±0.74D, NPT 0.01±0.52D, p=0.48; J45, PT -0.03±0.82D, NPT 0.00±0.52D, p=0.54).ConclusionsPattern of corneal astigmatism in eyes with cataract and coexisting primary pterygium was different from eyes without pterygium. Pterygium is associated with higher magnitude but not different axis of corneal astigmatism.

Project description:AimsThis study aimed to report corneal steep island (CSI) formation following primary pterygium surgery and to identify preoperative pterygium morphological features that predict the likelihood of CSI.MethodsA total of 93 eyes from 84 subjects with primary nasal pterygium, who underwent pterygium excision combined with conjunctival-limbal autograft, were included in this retrospective longitudinal cohort study. CSI was defined using anterior segment swept-source optical coherence tomography (AS SS-OCT). Eyes were divided into two groups: those with postoperative CSI formation (Group 1) and those without postoperative CSI (Group 2). We compared postoperative anterior corneal astigmatism (ACA, in diopters [D]) and root mean square (RMS) values of anterior corneal lower-order (LoA) and higher-order aberrations (HoA) between the groups. Baseline clinical severity grades of pterygium based on the pre-established pterygium body morphology and vascularity, ACA, and AS SS-OCT-guided pterygium morphological profiles (horizontal invasion length [HIL, mm], height [μm], thickness (μm), and residual corneal thickness [RCT]/central corneal thickness [CCT] ratio [RCT/CCT]) were also compared.ResultsPostoperative CSI occurred in 26 eyes (28.0%) with a maximum follow-up duration of 22.9±27.4 months. Group 1 exhibited significantly higher postoperative anterior corneal RMS LoA and HoA, as well as the RMS values of the 4th to 6th orders. Although clinical severity grades of pterygium did not differ between groups, baseline ACA was higher in Group 1 (4.56±5.49 D vs. 2.70±3.80 D, P = 0.009). HIL (4.49±0.84 mm vs. 3.77±1.29 mm, P = 0.010) was higher in Group 1, while pterygium height (930.8±84.4 μm vs. 999.3±128.0 μm, P = 0.015) and RCT/CCT ratio (1.07±0.13 vs. 1.14±0.16, P = 0.049) were lower in Group 1.ConclusionsCSI may develop after primary pterygium surgery, particularly in patients with relatively higher preoperative ACA, longer HIL, and shorter height. Given that CSI can significantly increase both lower and higher-order aberrations, it is crucial to anticipate CSI probability and inform patients before surgery.

Dataset Information

The effect of pterygium on front and back corneal astigmatism and aberrations in natural-light and low-light conditions.

Background

Methods

Results

Conclusions

Publications

The effect of pterygium on front and back corneal astigmatism and aberrations in natural-light and low-light conditions.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets