Impact of Valsalva maneuver on corneal morphology and anterior chamber parameters

Effects of eyelid pressure on corneal tomography and biomechanics: Quantitative analysis using a novel blepharo-tensiometer

PURPOSE

This study aimed to validate a blepharo-tensiometer, and investigate the relationship between eyelid pressure (ELP) and corneal tomography/biomechanics.

METHODS

Repeatability of the blepharo-tensiometer was evaluated at different inclination angles: 10°, 15°, and 20° for the upper eyelid (U10, U15, and U20) and 45°, 50°, and 55° for the lower eyelid (L45, L50, and L55). Reproducibility was evaluated in terms of different operators and inclination angles. Both the maximum and average ELP were evaluated. Best-corrected visual acuity, manifest refraction spherical equivalent, eyelid types, palpebral fissure height, exophthalmometry, axial length, and corneal tomographic/biomechanical parameters were measured. Spearman analysis and generalized estimating equations were used to explore potential correlations.

RESULTS

This study included 36 eyes from 36 subjects. The ICCs for repeatability were comparable between different inclination angles, so U15 and L50 were selected for further analysis. The ICCs for reproducibility in terms of different operator or inclination angle also achieved good to excellent outcomes. Certain associations have been revealed between the ELP and corneal tomographic/biomechanical parameters. Tomographically, ELP influences corneal front J0, front asphericity, and the index of surface variance; whereas biomechanically, ELP affects the time at first applanation, deformation amplitude at highest concavity, and biomechanically corrected intraocular pressure.

CONCLUSIONS

The tensiometer showed good precision. The study also showed that ELP causes a flattening effect on the peripheral cornea, with greater ELP linked to better corneal biomechanical properties in healthy subjects. These findings may potentially illuminate new avenues in the field of corneal disorders and beyond.

The spike of acute angle closure after the epidemic downgrade of COVID-19 management: a hospital-based comparative study from China

PURPOSE

To analyse and compare the clinical characteristics and treatment outcomes of patients with acute angle closure (AAC) who presented before the COVID-19 pandemic, during the COVID-19 management and after their downgrading.

METHODS

Consecutive AAC patients were recruited from our hospital and divided into three groups: those treated before the COVID-19 pandemic (Group1), during the COVID-19 management (Group2) and after the management downgrade (Group3). The demographic variables, clinical characteristics, treatment methods and therapeutic outcomes of the groups were compared.

RESULTS

When compared to Groups1 and 2, Group3 showed a significantly higher incidence of AAC (0.27%, P < 0.001), a longer time from symptoms to treatment (TST; 160.88 ± 137.05 h, P = 0.031) and worse uncorrected visual acuity (P = 0.009) at presentation. In Group3, 68.9% had a history of COVID-19 and 28.5% developed ocular symptoms of AAC after taking medication for COVID-19 symptoms. The average time from the onset of COVID-19 to the appearance of eye symptoms was 3.21 ± 4.00 days.

CONCLUSIONS

The COVID-19 has had a multifaceted impact on the incidence of AAC. Therefore, it is crucial to strengthen health education on glaucoma, especially AAC. The prevention and timely treatment of AAC should be emphasised to combat global blindness.

Impact of Valsalva Manuever on Choroidal Vascularity Index, Central Choroid and Central Macula

BACKGROUND

Evaluation of the effects of the Valsalva maneuver on choroidal vascularity index, central choroid and the central macula.

METHODS

Eighty-four eyes of 42 healthy volunteers were evaluated in this prospective study. The central macular layer was assesed using the retinal map mode of the spectral domain OCT (Optovue RTVue XR, Optovue Inc., Fremont, CA), OCT images taken in the Enhanced Deep Imaging mode were transferred to the Image J program and the choroidal vascularity index and subfoveal choroidal thickness measurements were calculated.

RESULTS

The mean age of volunteers was 35.4±7.2 years. Choroidal vascularity index, subfoveal choroidal thickness, central macular thickness and intraocular pressure measurements in the resting position were 67.99±2.1%, 337.73±12.8 µm, 232.04± 8.4 µm, 14.04±2.5 mmHg respectively, during Valsalva maneuver were 69.44±2.1%, 351.15±12.2 µm, 238.84±8.1 µm, 19.4±5.4 mmHg respectively. There was a statistically significant increase during valsalva maneuver.

CONCLUSION

The valsalva maneuver may cause temporary changes in choroidal vascularity index, subfoveal choroidal thickness, central macular thickness and intraocular pressure. These measurements may be misinterpreted in situations where patients breath-hold inadvertantly causing the Valsalva maneuver.

Oküler biyometrik ölçümler ile pediatrik migren arasında ilişki

Amaç: Bu çalışmada pediatrik migren hastalarında biyometri ölçümlerinin ve ön segment parametrelerinin değerlendirilmesi ve sağlıklı çocuklarla karşılaştırılması amaçlanmıştır. Gereç ve Yöntem: Bu prospektif vaka-kontrol çalışmasına yaş ve cinsiyeti uyumlu 40 pediatrik migren hastası ve 45 sağlıklı çocuk dahil edildi. Ölçümlerden önce tüm katılımcılar tam bir oftalmolojik muayeneden geçirildi. Ön kamara derinliği (ÖKD), vitreus uzunluğu (VU), lens kalınlığı (LK), aksiyel uzunluk (AU), merkezi kornea kalınlığı (MKK), kornea hacmi (KH), ön kamara hacmi (ÖKH), iridokorneal açı (İKA), pupil çapı (PÇ) ve ortalama kornea kırıcılığı (Km) değerlendirildi. Tüm değerlendirmeler ataksız dönemde yapıldı. Fotofobisi olan ve olmayan migrenli hastalarda pupil çapı karşılaştırıldı. Diürnal varyasyondan en az oranda etkilenmek açısından göz içi basınç ölçümleri ve biyometri değerlendirmeleri günün aynı saatlerinde (10:00–12:00) yapıldı. Tüm katılımcıların sağ gözü çalışmaya dahil edildi. Bulgular: Pediatrik migren grubuyla (27 kız, 13 erkek) kontrol grubu (30 kız, 15 erkek) arasında ÖKD, VU, LK, AU, MKK, KH, ÖKH, İKA, PÇ, göz içi basıncı, sferik eşdeğer ve Km ölçümleri bakımından istatistiksel olarak anlamlı farklılık görülmedi. Migren grubu içerisinde fotofobisi olan hastalar ile olmayanların pupil çapları arasında anlamlı farklılık görülmedi. Sonuç: Pediatrik migren hastalarında biyometri, korneal topografi ve keratometri ölçümlerinde sağlıklı çocuklara göre farklılık görülmemektedir. Pediatrik migren ile oküler biyometrik ölçümler arasındaki ilişkiyi incelemek için daha geniş hasta popülasyonlu çalışmalara ihtiyaç vardır.

Immediate and cumulative effects of upper-body isometric exercise on the cornea and anterior segment of the human eye

Objectives

The execution of isometric resistance training has demonstrated to cause changes in the ocular physiology. The morphology of the cornea and anterior chamber is of paramount importance in the prevention and management of several ocular diseases, and thus, understating the impact of performing isometric exercise on the eye physiology may allow a better management of these ocular conditions. We aimed to determine the short-term effects of 2-minutes upper-body isometric effort at two different intensities on corneal and anterior eye morphology.

Methods

Eighteen healthy young adults performed a 2-minutes isometric biceps-curl exercise against two loads relative to their maximum strength capacity (high-intensity and low-intensity) in a randomized manner. An Oculus Pentacam was used to measure the corneal morphology and anterior chamber parameters in both experimental conditions at baseline, during the isometric effort (after 30, 60, 90 and 120 seconds), and after 30 and 120 seconds of passive recovery.

Results

We found that isometric effort causes an increase in pupil size (P < 0.001), and a decrease in the iridocorneal angle (P = 0.005), anterior chamber volume (P < 0.001) and K-flat (P < 0.001) during isometric effort, with these effects being more accentuated in high-intensity condition (P < 0.005 in all cases).Performing 2-minutes upper-body isometric effort did not alter anterior chamber depth, central corneal thickness, corneal volume, and K-steep (P > 0.05 in all cases).

Conclusions

Our data exhibit that performing 2-minutes of upper-body isometric exercise modifies several parameters of the corneal morphology and anterior eye biometrics, with these changes being greater for the high-intensity exercise condition. The findings of this study may be of relevance for the prevention and management of corneal ectasias and glaucoma.

Wearing Swimming Goggles Reduces Central Corneal Thickness and Anterior Chamber Angle, and Increases Intraocular Pressure

Purpose/Aim: To assess the changes in anterior eye segment biometrics and intraocular pressure during and after wearing swimming goggles.Materials and methods: Anterior segment biometry and intraocular pressure were assessed in 20 healthy young adults (22.2 ± 4.7 years) during the wearing of a drilled swimming goggle. The central corneal thickness, anterior chamber depth, anterior chamber volume, and anterior chamber angle, using the Pentacam rotating Scheimpflug camera (Oculus Optikgerate GmbH, Wetzlar, Germany), and intraocular pressure, using a rebound tonometer, were obtained before, at 2, 3.5, and 5 min of wearing swimming goggle, just after removal, as well as after 5 min of recovery.Results: During swimming goggles wear, there was a significant corneal thinning (54.8 ± 41.1 µm, p < .001, ƞ_p² = 0.532), iridocorneal angle reduction (2.6 ± 2.6 degrees, p < .001, ƞ_p² = 0.241) and intraocular pressure elevation (4.0 ± 1.9 mmHg, p < .001, ƞ_p² = 0.530). These changes returned to baseline values immediately after swimming goggle removal (corrected p-value <0.05 in all cases). No significant effects of swimming goggles use were observed for anterior chamber depth and anterior chamber volume.Conclusions: Wearing swimming goggles leads to acute corneal thinning, iridocorneal angle reduction, and intraocular pressure elevation. These findings may be of special relevance for individuals with corneal ectasias, as well as for individuals at high risk of glaucoma onset or progression.

Influence of holding weights of different magnitudes on intraocular pressure and anterior eye biometrics

PURPOSE

This study is aimed at determining the impact of holding weight corresponding to the 10% and 20% of participants' body weight during 5-min on intraocular pressure (IOP) and anterior eye biometrics.

METHODS

Eighteen healthy young adults grabbed two jugs with comfort-grip handles, which were filled with water in order to achieve the desirable load (10% and 20% of participants' body weight). A rebound tonometer and Oculus Pentacam were used to assess IOP and anterior segment biometrics, respectively, at baseline, after 0.5, 2, 3.5, and 5 min of holding weights, as well as after 0.5 and 2 min of recovery in each experimental condition (control, 10%, and 20%).

RESULTS

There was a significant effect of the load used on IOP (p = 0.016, ƞ_p² = 0.215) and anterior chamber angle (p = 0.018, ƞ_p² = 0.211), with the load corresponding to 20% of participants' body weight promoting a significant IOP rise (corrected p value = 0.035, d = 0.67), and anterior chamber angle reduction (corrected p value = 0.029, d = 0.69) in comparison with the control condition. No effects of holding weight were observed for anterior chamber depth and central corneal thickness (p > 0.348).

CONCLUSIONS

Our data evidence that holding weight during 5 min increases IOP and narrows the anterior chamber angle, being these effects significant when using a load corresponding to 20% of body weight. Based on the current outcomes, lifting or carrying heavy loads may be discouraged for glaucoma patients or individuals at high risk for glaucoma onset, although future studies should explore the clinical relevance of our findings.

Influence of the breathing pattern during resistance training on intraocular pressure

This study aimed to assess the effect of the breathing pattern during resistance training on intraocular pressure (IOP). Twenty physically active collegiate students (7 women and 13 men) performed sets of 10 repetitions against the 10-RM (repetition maximum) load during the back-squat and biceps-curl exercises following 3 different breathing patterns: (I) Valsalva: holding the breath during the entire repetition; (II) normal breathing: holding the breath and exhaling during the first and second phases of the repetition, respectively; and (III) modified breathing: inhaling and holding the breath during the first and second phases of the repetition, respectively. Rebound tonometry was used to measure IOP before exercise, after each of the 10 repetitions, and after 1 min of recovery. The breathing pattern significantly affected the changes in IOP values (p < 0.001, [Formula: see text] = 0.509) with the normal breathing pattern providing lower increases in IOP values compared to the Valsalva (p < 0.001, d = 1.47) and modified breathing (p < 0.001, d = 0.96). Higher IOP values were observed for the back-squat compared to the biceps-curl exercise (p = 0.003, [Formula: see text] = 0.384). A normal breathing pattern should be recommended to avoid abrupt increments in IOP during resistance training. These findings may be especially important for individuals at high risk for glaucoma onset or progression due to the necessity of maintaining stable IOP levels to avoid the progression of this disease. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings.

Effect of refractive status on Valsalva-induced anterior segment changes

PURPOSE

To evaluate the effect of the Valsalva maneuver (VM) on anterior segment parameters and its association with refractive status.

METHOD

In this prospective study, 120 eyes of 120 subjects were evaluated. Subjects were divided into three groups: myopic (n = 40 patients), hyperopic (n = 40 patients), and emmetropic (control group, n = 40 subjects). The anterior segment parameters, including keratometric, pachymetric, and anterior chamber parameters, were measured using the Sirius System (Costruzione Strumenti Oftalmici, Florence, Italy) before and during VM.

RESULTS

There was no statistically significant difference in corneal parameters including keratometric and pachymetric values at rest or during VM in myopic, hyperopic, and control groups (p > 0.05 for all). In the myopic and control groups, anterior chamber depth, anterior chamber volume (ACV), and anterior chamber angle (ACA) were significantly decreased during VM. In the hyperopic group, only anterior chamber depth was significantly decreased during VM, while ACV and ACA did not significantly change.

CONCLUSION

The Valsalva maneuver may cause significant narrowing in anterior chamber depth, anterior chamber volume, and anterior chamber angle in the myopic and emmetropic groups, whereas it may affect only anterior chamber depth in the hyperopic group.

Anterior but not posterior choroid changed before and during Valsalva manoeuvre in healthy Chinese: a UBM and SS-OCT study

PURPOSE

To determine if the anterior choroid is involved in ocular change during the Valsalva manoeuvre (VM).

MATERIALS AND METHODS

Fifty-three healthy volunteers aged 18-65 years with normal visual field test results and no history of intraocular pressure (IOP) exceeding 21 mm Hg were recruited. Anterior and posterior choroidal changes before and during VM were recorded by ultrasound microscope and swept-source optical coherence tomography, respectively. Parameters of the anterior segment included ciliary body thickness (CBT0), thickness of the choroid at a distance of 4 mm from the root of the iris (CT4), anterior placement of the ciliary body (APCB) and trabecular-ciliary angle (TCA). Thickness of different layers of retina and posterior choroid were also measured and compared before and during VM. IOP, blood pressure (BP), heart rate (HR), axial length, spherical equivalent refractive error and pupil diameter (PD) were also recorded and analysed.

RESULTS

VM caused elevated IOP, systolic BP, diastolic BP and increased HR. There was a significant increase in anterior parameters including CBT0, CT4 and APCB (p<0.001), but not in TCA or PD (p>0.05). The mean change of CBT0, CT4 and APCB were: from 1.00±0.09 mm to 1.11±0.10 mm (p<0.001), from 0.29±0.04 mm to 0.36±0.05 mm (p<0.001), from 0.76±0.11 mm to 0.88±0.13 mm (p<0.001), respectively. However, there is no significant change in posterior choroid (from 215.74±60.23 µm to 214.82±61.32 µm, p=0.17).

CONCLUSION

We found that VM did not affect the posterior choroid, but it did cause thickening of the anterior choroid and the ciliary body, both of which led to a larger anterior placement of the ciliary body and a narrowed anterior chamber. The anterior (but not the posterior) choroid could be related to IOP elevation and a narrowed anterior chamber in primary angle closure diseases.

Intraocular pressure and ocular biometric parameters changes in migraine

Background

The aim of this study was to assess the intraocular pressure and ocular biometric parameters in migraine patients during acute migraine attacks and compare them with painless period and healthy controls using a new optical biometer AL-Scan.

Methods

In this prospective, case–control study, the axial length, corneal curvature radius, anterior chamber depth, central corneal thickness, and pupil size of 40 migraine patients during acute migraine attacks and painless period and 40 age- and sex-matched healthy subjects were measured using a AL-Scan optical biometer (Nidek Co., Gamagori, Japan). All patients underwent a complete ophthalmic examination before the measurements. IOP and biometer measurements were taken at the same time of day (10:00–12:00) in order to minimize the effects of diurnal variation.

Results

There was not a statistically significant difference in intraocular pressure between the migraine patients during acute migraine attacks (15.07 mmHg), painless period (14.10 mmHg), and the controls (15,73 ± 0,81). Also, the ocular biometric parameters did not significantly vary during the acute migraine attacks.

Conclusions

Further studies are needed to evaluate the etiopathologic relationship between intraocular pressure and ocular biometric parameters and acute migraine attack.

Does Valsalva Maneuver Affect Corneal Morphology in Eyes With Keratoconus?

OBJECTIVES

The aim of this study was to investigate the effect of the Valsalva maneuver on corneal morphology and anterior chamber parameters in patients with keratoconus.

METHODS

A total of 39 eyes from 39 patients with keratoconus and 41 eyes from 41 age-matched and gender-matched healthy individuals were included in this cross-sectional study. Measurements of corneal front keratometry values (K-flat, K-steep, and K-max), central corneal thickness, corneal apex thickness, thinnest corneal thickness, corneal volume, anterior chamber volume (ACV), anterior chamber depth (ACD), and iridocorneal angle (ICA) were performed with a Pentacam Scheimpflug camera (Oculus, Germany) before and during the Valsalva maneuver. Changes in the anterior segment parameters from baseline and during the Valsalva maneuver and the differences in parameters between the keratoconus group and the control group were analyzed. A P value less than 0.05 was accepted as statistically significant.

RESULTS

In the patients with keratoconus, the Valsalva maneuver did not have any significant influence on the corneal parameters (P>0.05). However, ACV, ACD, and ICA decreased markedly during the Valsalva maneuver (P=0.006, P=0.048, and P=0.025, respectively). Changes caused by the Valsalva maneuver were similar for all parameters when compared with those in healthy individuals (P>0.05).

CONCLUSIONS

During corneal topography imaging, the Valsalva maneuver observed in patients with keratoconus does not typically cause any significant change in corneal morphology.

Effects of Valsalva Maneuver on Ocular Biometric Parameters: Optical Low-Coherence Reflectometry Biometer Study

PURPOSE

To evaluate the effects of the Valsalva Maneuver (VM) on ocular biometry and intraocular pressure (IOP).

METHODS

This prospective observational study included 55 eyes of 55 healthy volunteers. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), corneal curvature (K-steep, K-flat and K-mean), corneal diameter (WtW), and pupil diameter (PD) were measured with a LenStar LS 900® biometer at rest and during VM. The IOP was also measured at rest and during VM measurements were compared.

RESULTS

The VM did not have any significant influence on AL, WtW, K-flat, and K-mean (p > 0.05), but it decreased K-steep significantly (p < 0.001). Moreover, CCT and ACD decreased significantly during VM (p < 0.001), but VM increased IOP, PD (p < 0.001), and LT significantly (p = 0.002).

CONCLUSIONS

The VM might reversibly change in IOP and ocular biometry, so it should be considered during anterior segment examinations.