Eyeball Volume Research Articles

The three-dimensional MRI for estimating the shape of eyeball of emmetropia and myopia

Objective To investigate the morphologic characteristics of eyeballs in myopia with three-dimensional magnetic resonance imaging(3-D MRI). Methods The emmetropia (10 cases, 20 eyes), low myopia (10 cases, 20 eyes), medium myopia (10 cases, 20 eyes), high myopia (10 cases, 20 eyes) were enrolled. Patients which had eye diseases, history of ocular injury or surgery were excluded. In all cases the 3-D MRI were taken for the measurement of the sagittal, horizontal and vertical diameter of eyeball, eyeball volume and the ending points of eye muscle and optic nerve. Results The average value of sagittal, horizontal and vertical length of low myopia, medium myopia and high myopia group were much bigger than those of emmetropia group, especially the axial length. The average value of eyeball volume of myopia group was much bigger than that of emmetropia group. The eyeball, eye muscles and optic nerve were showed clearly in the 3-D MRI. The low and medium myopia group did not present obvious posterior staphyloma. Fifteen of 20 eyeballs in the high myopia group showed posterior staphyloma. Conclusion The sagittal, horizontal and vertical diameters and volume of the eyeball of low myopia, medium myopia and high myopia are significantly bigger than those of emmetropia. The 3-D MRI can show the eyeball shape, eye muscles and optic nerve clearly, which has the certain value in clinical work especially for eye surgery. Key words: Myopia; Diameter, eyeball; Volume, eyeball; Three-dimensional MRI

Estimation of the Eyeball Volume on Magnetic Resonance Images in Zaria, Nigeria

Background: Decrease or increase in eyeball volume (EV) may indicate ocular pathology. Unfortunately the reference values utilized for EV in Nigeria has been that of Caucasians. There is paucity of literature on EV measurements in Nigeria and none (to the best of our knowledge) on magnetic resonance imaging (MRI) EV biometry in Nigeria. Aim: To establish the normal EV in healthy population in Zaria using a reliable MR imaging. Patients and Methods: The EV volumes of 100 consecutive 'normal' patients who had MRI scan done (using Siemens MR imaging permanent magnet, 0.2T) were calculated. The dimensions were obtained at mid-ocular axial slices with maximum anterior-posterior dimension and maximum size of the eye lens. Results: The mean EV of the right eye was 6.75 ± 1.01 cm 3 while that of the left was 6.74 ± 0.95 cm 3 . The mean EV in the males' right eye was 6.86 ± 0.98cm 3 while that of the left eye was 6.97 ± 0.99 cm 3 . Whereas, the mean ± right VE in the females was 6.61 ± 1.03 cm 3 while that of the left eye was 6.52 ± 0.86. VE correlated with the patients' age with P < 0.001 for both sides. Conclusion: The EV of males is larger than that of females but not statistically significant. EV was observed to increase with age, but it declined after age 40 years. The study also established EV in a sample of normal population in Zaria with the hope that it will serve as reference values in that local environment.

Is orbital volume associated with eyeball and visual cortex volume in humans?

Background: In humans orbital volume increases linearly with absolute latitude. Scaling across mammals between visual system components suggests that these larger orbits should translate into larger eyes and visual cortices in high latitude humans. Larger eyes at high latitudes may be required to maintain adequate visual acuity and enhance visual sensitivity under lower light levels.Aim: To test the assumption that orbital volume can accurately index eyeball and visual cortex volumes specifically in humans.Subjects and methods: Structural Magnetic Resonance Imaging (MRI) techniques are employed to measure eye and orbit (n = 88) and brain and visual cortex (n = 99) volumes in living humans. Facial dimensions and foramen magnum area (a proxy for body mass) were also measured.Results: A significant positive linear relationship was found between (i) orbital and eyeball volumes, (ii) eyeball and visual cortex grey matter volumes and (iii) different visual cortical areas, independently of overall brain volume.Conclusion: In humans the components of the visual system scale from orbit to eye to visual cortex volume independently of overall brain size. These findings indicate that orbit volume can index eye and visual cortex volume in humans, suggesting that larger high latitude orbits do translate into larger visual cortices.

Correlation Between Orbital Volume, Body Mass Index, and Eyeball Position in Healthy East Asians

The objectives of this study were measure the orbital volume of healthy Koreans and analyze the differences between orbital tissue volume with respect to age and sex and to assess any correlation between body mass index (BMI), eyeball position, and orbital volume. We retrospectively evaluated the scan results of patients who had undergone orbital computed tomography scans between November 2010 and November 2011. We assessed the scan results of 184 orbits in 92 adults who had no pathology of the orbit. The individuals were classified into 3 groups with respect to age. Orbital volume, effective orbital volume (defined as the difference between orbital and eyeball volume), extraocular muscle volume, orbital fat volume, and transverse globe protrusion were recorded and analyzed. The records of the subjects were reviewed retrospectively, and BMI was calculated. A correlation analysis was performed to investigate the correlation between BMI, eyeball position, and orbital volume. Orbital tissue volume, with the exception of orbital fat volume, was larger in men compared with women. In both sexes, orbital fat volume increased with increasing age, whereas the other volumes decreased. Orbital tissue volumes increased with increasing BMI, but transverse globe protrusion was not significantly related to BMI. In addition, orbital volume and effective orbital volume were positively correlated with transverse globe protrusion. These results provide basic information about the effects of age, sex, and BMI on orbital volume and eyeball position in healthy Koreans. Furthermore, these results will be helpful in the diagnosis of orbital diseases and in planning orbital surgeries.

Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies.

Ocular Volumetry Using Fast High-Resolution MRI during Visual Fixation

Volumetry may be useful for evaluating treatment response and prognosis of intraocular lesions. Phantom, volunteer, and patient studies were performed to determine whether ocular MR volumetry is reproducible. Half-Fourier single-shot RARE and FSPGR sequences at 1.5T with a 76-mm-diameter surface coil were optimized to obtain still ocular images. Volumetry accuracies of each sequence were compared with simulated subretinal phantom volumes. Ocular volumetry was performed in 15 volunteers twice in 1 week by using contiguous axial images of the globes while the subjects stared at a target, and images were acquired in 2 seconds before the subjects were instructed to blink, with this process repeated as necessary. Imaging, intraobserver, and interobserver reproducibility for volumes of the whole eyeball and anterior chamber were assessed. Ocular volumetry was also performed in 6 patients with intraocular tumors before and after treatment. The phantom study demonstrated that measurement error rates with RARE were significantly lower than with FSPGR (P<.01). The volunteer study demonstrated excellent imaging and intraobserver reproducibility of RARE volumetry for whole eyeballs and anterior chambers (P<.01). Although no interobserver differences were observed in anterior chamber volume measurement (P=.33), there was a significant difference between the 2 observers in eyeball volume measurement (P<.01). Follow-up volumetric data were useful for treatment decisions in all patients. Ocular volumetry from contiguous ultrafast RARE images obtained during visual fixation is feasible in volunteer and patient studies and is superior to FSPGR images.

Local recurrence after uveal melanoma protontherapy: prognostic consequences

AbstractPurpose To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapyMethods This retrospective study analyzed 61 cases of uveal melanoma local recurrence on a total of 1102 patients treated with protontherapy between June 1991 and December 2010. Survival rates have been determined by using Kaplan‐Meier curves. Prognostic factors have been evaluated by using Log‐rank test or Cox model.Results Our local recurrence rate was 5.5%. These recurrences were divided into: 25 patients with marginal recurrences, 18 global recurrences, 12 far recurrences and 6 extra‐scleral extensions. 4 factors have been identified as statistically significant risk factor of local recurrence in univariate analysis: large tumoral diameter, weak tumoral volume, weak ratio of tumoral volume over eyeball volume and safety margin inferior to 1 mm. In the local recurrence free population, the overall survival rate was 59.8% at 15 years and the specific survival rate was 80.9% at 15 years. In the local recurrence population, the overall survival rate was 34.5% at 15 years and the specific survival rate was 55% at 15 years. Kaplan‐Meier survival curves have shown a better prognosis for marginal recurrences compared to the other recurrences.Conclusion Survival rate of marginal recurrences is highly superior to the other recurrences. The type of recurrence is an important clinical prognostic value to know.

Digital Evaluation of Orbital Development in Chinese Children With Congenital Microphthalmia

To evaluate the asymmetry of bilateral orbital development in Chinese children with congenital microphthalmia and to provide a criterion for tailoring treatment timing and therapy. Retrospective cohort study. By combining multisection helical computerized tomography imaging with a computer-aided design system, we measured 38 children between 0 and 6 years of age with congenital microphthalmia and 70 normal children of the same age group. Variables were measured, including orbital volume, depth, width, and height and eyeball volume. Displacement of the orbital rims was calculated by mirroring the unaffected orbit across the midsagittal plane of body. Significant differences were observed between the orbital volume, eyeball volume, orbital width, and orbital height of the affected and unaffected sides of children with congenital microphthalmia (P < .001). The difference between the orbital depth of the affected and unaffected sides was not significant (P = .055). Growth of the inferior and lateral rims retarded by an average of 3 mm, whereas that of the medial and superior rims retarded by less than 1 mm. The amount of decrease in orbital volume of children with congenital microphthalmia is related to the severity of the disease (decrease in size of the eye), rather than to age. Retarded orbital development is evident primarily in the inferior and lateral rims, correlating mostly with zygomatic and then maxilla and frontal bone. The growth of the affected orbit slows down or even stagnates by 3 years of age. Intervention therapy before 3 years of age was critical.

Measurement of human eye volume in vivo with MRI and its clinical value

Background The quantitative analysis of the relationship between the vitreous volume with diopter and axial length in high myopic eye can offer a valuable basis for relevant clinical research. However, how to measure the ocular volume in vivo is a problem. Objective This study was to measure the eyeball volumes with magnetic resonance imaging ( MRI) and compare the difference of ocular volume between emmetropic and high-myopic eyes in order to explore the influent factors of changes of eyeball volumes. Methods The volumes of ocular anterior segment,lens and vitreous were measured using MRI( 1.5-T) in 60 emmetropic eyes and 60 high-myopic eyes. The ocular axial lengths of the subjects were measured by A-scan ultrasonography. The alterations of vitreous volumes with the changes of axial lengths and diopters were evaluated by linear regression analysis. Written informed consent was obtained from each patient before any medical examination. Results The mean diopters of high myopic eyes was ( - 15. 62 ± 8. 27 ) D and the mean axial lengths were ( 28. 68 ± 2. 68 ) mm, showing a significantly positive correlation between them(R2=0. 830,P = 0. 000). The mean total ocular volumes were(7.46±0. 89)ml3 and those of vitreous were ( 6. 90 ± 0. 8 ) ml3 in the high-myopic eyes with a significant increase in comparison with emmetropic eyes [ ( 6. 00 ± 0. 35 ) ml3 and ( 5. 41 ±0. 32 ) ml3 ] ( t = - 11. 846, P = 0. 000; t = - 12. 1, P = 0. 000 ). However,no significant differences were found in the anterior segment volumes and lens volumes between high myopic eyes and emmetropic eyes (t = 1. 23, P = 0. 220; t = -0. 483 , P = 0. 630 ). The vitreous volumes of high myopic eyes were significantly correlated with the diopters and the axial lengths (R2 =0. 75 ,P = 0. 000 ;R2 =0. 85 ,P = 0. 000) ,and so were the total ocular volumes (R2 = 0. 7543, P = 0. 000; R2 = 0. 8413, P = 0. 000). Conclusion The alteration of vitreous volumes is a mainly cause of difference of total ocular volume in ammetropic eyes. In high myopic eye, vitreous volume has a good linear correlation with refractive error and axial length, which may offer valuable information for vitrectomy. Key words: Eyeball/vitreous volume/measurement; Magnetic resonance imaging; High myopia; Axial length; A-scan ultrasonography

Effective Orbital Volume and Eyeball Position: An MRI Study

Purpose: Previous studies have examined factors affecting the position of the eyeball to the orbit. This study examined the role of effective orbital volume (EOV), defined as the difference between orbital and eyeball volume, as a determinant of eyeball position, using MRI scans.Methods: Forty-six patients were recruited from the Department of Ophthalmology of the University Hospital of Heraklion, Crete Greece. Patients with a history of orbital disease were excluded. Distances between eyeball poles and orbital landmarks were measured in T1 weighted transverse, sagittal and coronal orbital images. The protrusion of the eyeball in the sagittal and transverse planes was recorded. The volume of the eyeball and bony orbit, the EOV, the volume of the extraocular muscles as well as clinical information (age, gender, Hertel exophthalmometry) were also recorded.Results: EOV was significantly associated with orbital volume but not with eyeball volume. EOV was also significantly associated with transverse and sagittal globe ptotrusions. Females displayed significantly lower orbital and eyeball volumes as well as EOV than males but higher transverse globe protrusion than males.Conclusions: Variations in EOV are associated with orbital volume rather than with eyeball volume. EOV is associated with globe protrusion and may be taken into account in the planning of various procedures, including orbital decompression, treatment of enophthalmos or the size of orbital implants following enucleation.

Fetal eyeball volume: relationship to gestational age and biparietal diameter

To measure and determine normal values of the fetal eyeball volume between 14 and 40 weeks of gestation. The volume of the fetal eyeball was measured with three-dimensional ultrasound between 14 and 40 weeks of gestation using the VOCAL software.Only singleton pregnancies without fetal growth restriction, diabetes mellitus, hypertension or major fetal malformation were included. Over all, 203 women were studied. In 125 both eyeballs were measured while in 78 only one eyeball was measured. The volume of the eyeball correlated strongly with gestational age (right: R = 0.946, P < 0.001, n = 171. left: R = 0.945, P < 0.001, n = 156), and with the biparietal diameter (BPD) (right: R = 0.949, P < 0.001, n = 171. left: R = 0.953, P < 0.001, n = 156). Using regression analysis the best correlation between eyeball volume and the BPD were: square of right eyeball = -0.180 + 0.187 BPD, square of left eyeball = -0.182 + 0.187 BPD. The volume of the eyeball has strong positive correlations with gestational age and BPD. Our data may be helpful in fetuses suspected of having eye anomalies.

Unbiased Estimation of the Eyeball Volume Using the Cavalieri Principle on Computed Tomography Images

The size of the eyeball has been the subject of a few studies. None of them used stereological methods to estimate the volume. In the current study, we estimated the volume of eyeball in normal men and women using the stereological methods. Eyeball volume (EV) was estimated using the Cavalieri principle as a combination of point-counting and planimetry techniques. We used computed tomography scans taken from 36 participants (15 men and 21 women) to estimate the EV. The mean (SD) EV values obtained by planimetry method were 7.49 (0.79) and 7.06 (0.85) cm in men and women, respectively. By using point-counting method, the mean (SD) values were 7.48 (0.85) and 7.21 (0.84) cm in men and women, respectively. There was no statistically significant difference between the findings from the 2 methods (P > 0.05). A weak correlation was found between the axial length of eyeball and the EV estimated by point counting and planimetry (P < 0.05, r = 0.494 and r = 0.523, respectively). The findings of the current study using the stereological methods could provide data for the evaluation of normal and pathologic volumes of the eyeball.

Comparison of corneal endothelial cell loss during phacoemulsification using continuous anterior chamber infusion versus those using ophthalmic viscosurgical device: Randomized controlled trial

AimWe conducted this study to evaluate and compare corneal endothelial cell loss between phacoemulsification with continuous anterior chamber infusion using anterior chamber maintainer (ACM) and phacoemulsification using ophthalmic viscosurgical device (OVD).Materials and MethodsThis was a prospective, randomized controlled trial. Fifty eyes of 47 patients of senile cataract undergoing phacoemulsification were included. Patients were randomly allocated into two groups of 25 eyes each. Cataract surgery was performed by phacoemulsification with anterior chamber (AC) continuous infusion with balanced salt solution (BSS) plus and ACM without OVD in Group A, and in Group B, phacoemulsification was performed using OVD with BSS plus. Corneal endothelial cell count and pachymetry were performed preoperatively and postoperatively on day 1, day 7, and day 30.ResultsThe mean increase in pachymetry was 4.86%, 2.94%, and 1.94%, (Group A) and 5.95%, 3.94%, and 0.51%, (Group B) on first, seventh, and 30th postoperative day respectively. The difference between the percentage increase in pachymetry between the two groups was not significant at day 1 (P = 0.441), day 7 (P = 0.298), and day 30 (P = 0.174) postoperatively. The density of endothelial cells decreased postoperatively (day 30) by 7.38% (Group A) and 7.47% (Group B) without any significant statistical difference (P = 0.983) between two groups.ConclusionUse of ACM for continuous AC infusion and omission of OVD during phacoemulsification did not cause significant difference in corneal swelling or endothelial cell loss in the immediate postoperative period up to one month.

Study on the growth of orbital volume in individuals at different ages by computed tomography

To study the growth aspects of orbital volume and to establish the normal value of orbital volume by computed tomography (CT). One hundred and twenty three individuals without eye diseases (64 males, 59 females) were divided into 5 groups according to the age. Orbital volume and length of horizontal transverse axis and anterior-posterior axis of the eye were measured at different levels in original or reconstructive CT images. The relationship between orbital volume and age, gender and eyeball volume was analyzed. There was no difference between the left and right orbital volume in all age groups. Orbital volume grew rapidly before 20 years of old. Mean orbital volume in males aged 17 and females aged 13 was 23.54 and 21.75 ml, respectively, which reached 95% of the adult orbital volume. In normal adult, orbital volume in the male was larger than that of the female. The mean orbital volume of adult male and female was (25.04 +/- 2.37) ml and (22.89 +/- 2.67) ml, respectively. A strong linear correlation was presented between the age and orbital volume (P < 0.05). The difference of orbital volume between the male and female was statistically non-significant before 14 years old (P = 0.315). The growth of eyeball volume was consistent with that of the orbital volume, the ratio of eyeball/orbit volume was decreased with age from 0.40 to 0.26. There is no difference between the right and left orbital volume. Orbital volume is correlated with age and gender. Orbital volume grows rapidly before 20 years of old and still grows slowly after 40 years old.

The volume and dimensions of eyeball analyzed by MRI following encircling scleral buckles

To assess the changes of the volume and dimensions of the eyeball and the vitreous following encircling scleral buckle. 26 eyes from 26 patients received successful broad-band encircling scleral buckles for rhegmatogenous retinal detachment from July 2002 to December 2003. The examinations, A-scan ultrasonography (SONOMED A-5500, USA), Corneal topography and MRI, were performed preoperatively and at the first week postoperatively. The volume of the eyeballs and the dimensions along the three cardinal axes from 13 eyeballs were measured with Gyroscan MR imaging system. The measurement of MRI for the 13 eyes operated with the encircling scleral buckling revealed that the volume of the eyeball was decreased (1.72 +/- 0.49) ml, and volume of vitreous was decreased (1.73 +/- 0.46) ml in the comparison with volume before surgery. Horizontal and vertical dimensions of eyeball were decreased (7.84 +/- 1.86) mm, (7.70 +/- 2.79) mm respectively. The length of circumference was decreased to (24.42 +/- 6.68) mm, the percentage of the decrease was (33.11 +/- 8.69)%. The average high of the buckle indentions was (3.80 +/- 0.58) mm with the average width of (3.82 +/- 0.60) mm in the temperal part and (3.51 +/- 0.76) mm in the nasal part. The length of the circumference at the site of buckling is shorted, and the volume of the vitreous was decreased after the surgery. The technique of MRI has an important role in the measurement and analysis of the volume and the dimension of the eyeball.

ADDITIONAL INTRAVITREAL GAS INJECTION IN THE EARLY POSTOPERATIVE PERIOD FOR AN UNCLOSED MACULAR HOLE TREATED WITH INTERNAL LIMITING MEMBRANE PEELING

To study the efficacy of additional intravitreal gas injection for unclosed macular holes within 2 weeks after surgery with internal limiting membrane peeling. We reviewed the results for five consecutive eyes receiving additional intravitreal gas injection for unclosed macular holes within 2 weeks after initial macular hole surgery with internal limiting membrane peeling. The initial surgery consisted of standard pars plana vitrectomy with phacoemulsification and intraocular lens implantation, indocyanine green-assisted peeling of the retinal internal limiting membrane, and fluid-gas exchange with 20% sulfur hexafluoride. The patients were instructed to assume face down positioning for > or =7 days after surgery. If an unclosed macular hole was found after the residual gas volume decreased to <30% of the eyeball volume, fluid-gas exchange was performed using 15% octafluoropropane. All five eyes receiving additional intravitreal gas 7 to 14 days after vitrectomy had complete macular hole closure with macular flattening, as shown by optical coherence tomography 1 month after the additional gas injection. Visual acuity improved (range, 20/100 to 20/30). A minimum of 9 months of follow-up revealed no reopening or serious complications. Additional gas injection during the early postoperative period is recommended for eyes with unclosed macular holes that have undergone vitrectomy with internal limiting membrane peeling.

Normal orbital volumes and its pathology in orbital socket surgery

The present article reviews current knowledge on orbital volumes in the anophthalmic socket and presents the authors' own results on the volumetry of the bony and soft tissue compartments following enucleation. These results provide strong evidence that enucleation in both children and adults is associated with a reduction of bony orbital volume and that this decrease in orbital volume increases with time. However, the reduction is smaller than generally assumed and does not cause obvious facial asymmetry. It is more related to the time interval since enucleation than the age at enucleation, which makes a mechanism of volume adaptation more likely than just retardation of growth. However, based on animal studies, the extent and consequences of bony orbital changes after early enucleation in childhood have until now been overstimated. Loss of the eyeball takes major responsibility for soft tissue volume reduction and can be variable due to marked inter-individual variations. Primarily, there is no shortage of orbital fat in the anophthalmic socket. The post-enucleation socket syndrome is therefore caused by a lack of adequate eyeball volume replacement and possibly a redistribution, but no shortage of orbital fat. However, chronic inflammation, radiation and secondary orbital implantation can induce orbital fat artophy and contribute to the development of a post-enucleation socket syndrome. Extraocular muscle volumes play a minor role in volume changes.