SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Staphyloma

28

PURPOSE: To investigate the relationship between the size of the peripapillary crescent and different ocular parameters in highly myopic healthy eyes; in addition, to determine whether the area of the peripapillary crescent enlarged significantly during one year of observation. METHODS: The medical records of 49 highly myopic healthy eyes whose fellow eyes had myopic complications were reviewed. The area of the peripapillary crescent and other ocular parameters were measured initially and after one year. The changes in the area of the peripapillary crescent and their association with other ocular parameters during the natural course of the pathological myopia were determined. RESULTS: The area of the peripapillary crescent was significantly associated with the choroidal thickness (P < 0.001), axial length (P < 0.001), and foveal thickness (P < 0.01). Stepwise regression analyses found that the factors most associated with the area of the peripapillary crescent were the choroidal thickness (P < 0.01) and the absolute nasal staphyloma height (P < 0.05). The factor most associated with the increase in the area of the peripapillary crescent was the increase in the axial length (P < 0.01). CONCLUSIONS: The size of the peripapillary crescent may be affected by changes in the axial length, the height of the posterior staphyloma, and the choroidal thickness.

Concepts: Regression analysis, Eye, Myopia, Stepwise regression, Staphyloma

28

PURPOSE: To assess the repeatability and accuracy of optical biometry (Lenstar LS900 optical low-coherence reflectometry [OLCR] and IOLMaster partial coherence interferometry [PCI]) and applanation ultrasound biometry in highly myopic eyes. SETTING: Division of Preventive Ophthalmology, Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN: Comparative evaluation of diagnostic technology. METHODS: Biometric measurements were taken in highly myopic subjects with a spherical equivalent (SE) of -6.00 diopters (D) or higher and an axial length (AL) longer than 25.0 mm. Measurements of AL and anterior chamber depth (ACD) obtained by OLCR were compared with those obtained by PCI and applanation A-scan ultrasound. Right eyes were analyzed. Repeatability was evaluated using the coefficient of variation (CoV) and agreement, using Bland-Altman analyses. RESULTS: The mean SE was -11.20 D ± 4.65 (SD). The CoVs for repeated AL measurements using OLCR, PCI, and applanation ultrasound were 0.06%, 0.07%, and 0.20%, respectively. The limits of agreement (LoA) for AL were 0.11 mm between OLCR and PCI, 1.01 mm between OLCR and applanation ultrasound, and 1.03 mm between PCI and ultrasound. The ACD values were 0.29 mm, 0.53 mm, and 0.51 mm, respectively. These repeatability and agreement results were comparable in eyes with extreme myopia (AL ≥27.0 mm) or posterior staphyloma. The mean radius of corneal curvature was similar between OLCR and PCI (7.66 ± 0.24 mm versus 7.64 ± 0.25 mm), with an LoA of 0.12 mm. CONCLUSION: Optical biometry provided more repeatable and precise measurements of biometric parameters, including AL and ACD, than applanation ultrasound biometry in highly myopic eyes. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Concepts: Cornea, Ophthalmology, Accuracy and precision, Myopia, Refractive surgery, Presbyopia, Eyeglass prescription, Staphyloma

28

To study the choroidal thickness in eyes with inferior posterior staphyloma (IPS) and to elucidate its role in the development of macular complications.

Concepts: Optics, Medical imaging, Eye, Ophthalmology, Tomography, Staphyloma

27

BACKGROUND: To assess the role of Spectral Domain Optical Coherence Tomography (SD-OCT) measurements as prognostic factors in myopic macular hole (MMH) surgery. METHODS: In a retrospective cohort study, we evaluated 42 eyes of 42 patients (Spherical equivalent > -6.00 D) who underwent pars plana vitrectomy with internal limiting membrane peeling for MMH without foveoschisis. Statistical analysis was performed to correlate postoperative best corrected visual acuity (BCVA) with preoperative BCVA, age, degree of myopia and seven preoperative OCT measurements: macular hole (MH) base, MH minimum diameter, MH height, Hole Form Factor (HFF), Macular Hole Index (MHI), Diameter Hole Index (DHI) and Tractional Hole Index (THI). RESULTS: Primary and final anatomical success rate were 83.3 % (35/42) and 90.5 % (38/42), respectively. Four patients deferred reoperation and three underwent a second surgical approach to achieve MH closure. A posterior staphyloma was observed in 27 of 42 patients, and in three of them the MH was located in the apex of the staphyloma. Two of these three cases showed an open MH after the first surgery. Postoperative visual acuity improved in 22/42 (52.4 %) patients, worsened in 7/42 (16.7 %) and remained unchanged in 13/42 (30.9 %). Only MH minimum diameter (P = 0.03) and HFF (P = 0.02) correlated significantly with postoperative BCVA. CONCLUSIONS: Minimum diameter and HFF are strongly correlated with postoperative visual outcomes in cases of MMH. Since analyzing MH configuration seems to improve the anatomical success rate after vitreous surgery in highly myopic patients, these parameters should be preoperatively evaluated by SD-OCT.

Concepts: Cohort study, Retina, Ophthalmology, Vitrectomy, Optical coherence tomography, Myopia, Eyeglass prescription, Staphyloma

27

BACKGROUND AND OBJECTIVE:Macular anatomic abnormalities in high myopia are more frequent in the presence of posterior staphyloma. The objective was to determine the prevalence of foveoschisis, foveal detachment, vascular traction, epiretinal membrane (ERM), and macular hole (MH) in eyes with high myopia by spectral-domain optical coherence tomography. PATIENTS AND METHODS:Prospective, observational study. Eyes with myopia greater than 8 diopters (D) were included. Results were analyzed using chi-square and Student’s t tests. RESULTS:The study included 116 eyes of 72 patients. Mean spherical equivalent: -15.04 ± 5.33 D. Mean axial length: 28.88 ± 2.31 mm. Foveoschisis was observed in 17 eyes (14.65%), vascular traction in 17 (14.65%), ERM in 13 (11.2%), lamellar MH in two (1.72%), and posterior staphyloma in 41 (35.34%). Presence of foveoschisis, vascular traction, and ERM was more frequent in eyes with posterior staphyloma (P = .0001). CONCLUSION:Macular anatomic abnormalities were observed in 22.41% of eyes with high myopia and in 53.65% of eyes with posterior staphyloma.

Concepts: Scientific method, Optics, Eye, Ophthalmology, Normal distribution, Myopia, Eyeglass prescription, Staphyloma

27

Posterior staphyloma is a concave depression of the posterior shell of the eye globe that is frequently observed in highly myopic eyes. As hallmark lesion, it is seen in 90% of patients with high myopia and increases in prevalence with age.1 Highly myopic eyes with posterior staphylomata have a higher probability of visual disturbances; the stretching of the posterior fundus results in various lesions such as chorioretinal atrophy, choroidal neovascularization, lacquer cracks, foveoschisis, macular holes and serous macular detachments. 2 It has been observed that with age, posterior staphylomata tend to deepen and their morphological characteristics can change accompanied by an increased risk of complications. Optical coherence tomography (OCT) is a valuable non-invasive tool in the monitoring and evaluation of these patients by providing detailed cross-sectional structural information of vitreo-retinal structures. Spectral domain OCT (SD-OCT) encodes depth information as different frequencies of the interference spectrum. With increasing depth, the interferometric signals have higher frequencies and occur further from the point of detection or the “zero-delay line”, resulting in a decrease in resolution and signal strength. With zero delay normally located at the top portion of the OCT viewing screen, vitreoretinal structures can be visualised with optimal definition. Recently, Spaide described a technique where by advancing the camera closer to the eye so that the image became inverted, the choroidoscleral portion of the image was placed closer to the zero delay. This technique, also called enhanced-depth imaging (EDI) has now been incorporated into the OCT acquisition software so that the zero delay can be set to the bottom of the viewing screen to enhance definition of the deeper structures.(3).

Concepts: Optics, Retina, Eye, Visual perception, Ophthalmology, Optical coherence tomography, Myopia, Staphyloma

27

PurposeThe purpose of this study was to determine the subfoveal scleral thickness in highly myopic eyes by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and to identify the ocular parameters significantly associated with the scleral thickness.MethodsThe subfoveal scleral thickness of myopic eyes (≥-8 diopters (D) or axial length ≥26.5 mm) was examined by EDI-OCT. The correlations between the thickness and the best-corrected visual acuity (BCVA), refractive error, axial length (AL), the subfoveal retinal thickness, choroidal thickness, and posterior staphyloma height 2 mm from the fovea were investigated.ResultsA total of 75 eyes of 54 patients (21 men, 33 women; mean age, 62.3±11.3 years; mean AL, 30.2±1.68 mm) were studied. Eighteen eyes had no pathological retinochoroidal lesions, and 57 eyes had retinochoroidal lesion, that is, myopic schisis, choroidal neovascularization, and other retinochoroidal pathologies. The mean subfoveal scleral thickness was 284.0±70.4 μm, and the thickness was significantly correlated negatively with the absolute value of the nasal and overall average posterior staphyloma height (P<0.05 and P<0.01, respectively). The subfoveal scleral thickness was also significantly correlated negatively with the relative value of the superior, nasal, and overall average posterior staphyloma height (P<0.05, P<0.01, and P<0.001, respectively). Stepwise analyses showed that the factor most significantly associated with the scleral thickness was the average relative posterior staphyloma height (F=16.0, P<0.001). The scleral thickness was not significantly different between eyes with and without myopic retinochoroidal pathologies (P>0.05).ConclusionPosterior staphyloma formation was a key factor associated with a posterior scleral thinning in highly myopic eyes.Eye advance online publication, 11 January 2013; doi:10.1038/eye.2012.289.

Concepts: Optics, Retina, Eye, Visual acuity, Arithmetic mean, Ophthalmology, Myopia, Staphyloma

4

Worldwide, and especially in Asia, myopia is a major vision-threatening disorder. From AD 1600 on, to prevent myopia, authors warned against near work without sufficient pauses. There was an abundance of theories about the causes of myopia, the most common one being the necessity of extra convergence on nearby work with thickened extraocular muscles and elevated intraocular pressure. Ocular tenotomies against myopia were in vogue for a while. Axial lengthening of the eye in myopia was mentioned around 1700, but it took 150 years to become accepted as the most prevalent sign of high myopia. In 1864, a lucid concept of myopia and other ametropias arose through a clear separation between accommodation and refraction. Posterior staphyloma was known around 1800 and its association with myopia became evident some 30 years later. There still seems to be no generally accepted classification of myopia and particularly not of degenerative or pathologic myopia. This review focuses on myopia from 350 BC until the 21st century and on the earliest writings on the histology of eyes with posterior staphyloma. A proposal for myopia classification is given.

Concepts: Energy, Eye, Intraocular pressure, Myopia, 21st century, January 1, Staphyloma, In Vogue

0

Myopia is increasing rapidly worldwide. We performed a cross-sectional study to investigate the prevalence of posterior staphyloma, a complication of myopia, and its shape characteristics in relation to age, sex, and axial length (AL) in a Japanese community-based cohort. The right eyes of 3748 participants who underwent fundus photography and optical coherence tomography (OCT) examination were evaluated. Posterior staphyloma prevalence was evaluated using fundus photographs and OCT images. Furthermore, fundus shapes were analyzed by measuring local fundus curvatures on 6 mm cross-line OCT images at intervals of 1 µm. The mean and variance of the curvatures were calculated to represent the fundus shape of each eye for investigation of the relationship between fundus curvature and age, sex, and AL. Seventy-seven eyes (2.05%) had posterior staphyloma. The mean and variance of the fundus curvatures were significantly greater in women than in men and became greater with age, suggesting that the shape of the staphyloma was steeper and less smooth in women and elderly subjects. AL and mean curvature showed a significant correlation (P = 2 × 10-16, R = 0.480), which was significantly affected by age (P < 2 × 10-16). Quantitative analysis of fundus shapes was useful for statistical analysis of posterior staphyloma in relation to age, sex, and AL.

Concepts: Epidemiology, Statistics, Optics, Eye, Probability theory, Optical coherence tomography, Curvature, Staphyloma

0

To evaluate changes in the anterior segment of myopic eyes and assess anterior biometry as a function of axial length (AL).

Concepts: Myopia, Programming language, Staphyloma