AXIAL LENGTH INCREASES AND RELATED CHANGES IN HIGHLY MYOPIC NORMAL EYES WITH MYOPIC COMPLICATIONS IN FELLOW EYES

Association of macular outward scleral height with axial length, macular choroidal thickness and morphologic characteristics of the optic disc in Chinese adults

PURPOSE

To identify the relationship of macular outward scleral height (MOSH) with axial length (AL), macular choroidal thickness (ChT), peripapillary atrophy (PPA), and optic disc tilt in Chinese adults.

METHODS

In this cross-sectional study, 1088 right eyes of 1088 participants were enrolled and assigned into high myopia (HM) and non-HM groups. MOSH was measured in the nasal, temporal, superior, and inferior directions using swept-source optical coherence tomography images. The clinical characteristics of MOSH and the association of MOSH with AL, macular ChT, PPA, and tilt ratio were analysed.

RESULTS

The mean age of participants was 37.31 ± 18.93 years (range, 18-86 years), and the mean AL was 25.78 ± 1.79 mm (range, 21.25-33.09 mm). MOSH was the highest in the temporal direction, followed by the superior, nasal, and inferior directions (all p < 0.001). The MOSH of HM eyes was significantly higher than that of non-HM eyes, and it was positively correlated with AL in the nasal, temporal, and superior directions (all p < 0.001). Macular ChT was independently associated with the average MOSH (B = -0.190, p < 0.001). Nasal MOSH was positively associated with the PPA area and the presence of a tilted optic disc (both p < 0.01). Eyes with a higher MOSH in the superior (odds ratio [OR] = 1.008; p < 0.001) and inferior directions (OR = 1.006; p = 0.009) were more likely to have posterior staphyloma.

CONCLUSION

MOSH is an early indicator of scleral deformation, and it is correlated positively with AL and negatively with ChT. A higher nasal MOSH is associated with a larger PPA area and the presence of a tilted optic disc. Higher MOSH values in the superior and inferior directions were risk factors for posterior staphyloma.

CLINICAL TRIAL REGISTRATION

The study was registered at www.

CLINICALTRIALS

gov (Reg. No. NCT03446300).

Axial Elongation Trajectories in Chinese Children and Adults With High Myopia

Importance

Understanding the long-term axial elongation trajectory in high myopia is important to prevent blindness.

Objective

To evaluate axial elongation trajectories and related visual outcomes in children and adults with high myopia.

Design, Setting, and Participants

In this cohort study, participants in the Zhongshan Ophthalmic Centre-Brien Holden Vision Institute high myopia cohort were followed up every other year for 8 years. Participants with axial length measurements at baseline (2011 or 2012) and at least 1 follow-up visit were included. Participants were grouped according to baseline age as children and adolescents (7 to <18 years), young adults (18 to <40 years), and older adults (≥40 to 70 years). Data were analyzed from November 1, 2022, to June 1, 2023.

Exposure

High myopia (spherical power ≤-6.00 diopters).

Main Outcomes and Measures

Longitudinal axial elongation trajectories were identified by cluster analysis. Axial elongation rates were calculated by linear mixed-effects models. A 2-sided P < .05 was defined as statistically significant.

Results

A total of 793 participants (median [range] age, 17.8 [6.8-69.7] years; 418 females [52.7%]) and 1586 eyes were included in the analyses. Mean axial elongation rates were 0.46 mm/y (95% CI, 0.44-0.48 mm/y) for children and adolescents, 0.07 mm/y (95% CI, 0.06-0.09 mm/y) for young adults, and 0.13 mm/y (95% CI, 0.07-0.19 mm/y) for older adults. Cluster analysis identified 3 axial elongation trajectories, with the stable, moderate, and rapid progression trajectories having mean axial elongation rates of 0.02 mm/y (95% CI, 0.01-0.02 mm/y), 0.12 mm/y (95% CI, 0.11-0.13 mm/y), and 0.38 mm/y (95% CI, 0.35-0.42 mm/y), respectively. At 8 years of follow-up, compared with the stable progression trajectory, the rapid progression trajectory was associated with a 6.92 times higher risk of developing pathological myopic macular degeneration (defined as diffuse or patchy chorioretinal atrophy or macular atrophy; odds ratio, 6.92 [95% CI, 1.07-44.60]; P = .04), and it was associated with a 0.032 logMAR decrease in best-corrected visual acuity (β = 0.032 [95% CI, 0.001-0.063]; P = .04).

Conclusions and Relevance

The findings of this 8-year follow-up study suggest that axial length in high myopia continues to increase from childhood to late adulthood following 3 distinct trajectories. At 8 years of follow-up, the rapid progression trajectory was associated with a higher risk of developing pathological myopic macular degeneration and poorer best-corrected visual acuity compared with the stable progression trajectory. These distinct axial elongation trajectories could prove valuable for early identification and intervention for high-risk individuals.

What Should We Pay More Attention to Marfan Syndrome Expecting Ectopia Lentis: Incidence and Risk Factors of Retinal Manifestations

(1) Background: This paper investigates the incidence and risk factors of retinal manifestations in patients with Marfan syndrome (MFS) in a Chinese cohort. (2) Methods: This is a population-based cross-sectional study. In total, 344 eyes (172 MFS participants) were enrolled, each of whom underwent a detailed ocular examination. B-scan ultrasonography, ultra-wide-angle fundus images and optical coherence tomography images were conducted to assess posterior staphyloma, types of retinal damages and maculopathy. (3) Results: MFS patients have a high proportion (32.5%) of maculopathy, among which atrophy is the most common type (27.6%). Compared with participants without maculopathy, participants with maculopathy had a longer axial length (AL), higher incidence of posterior staphyloma, macular split and retinal detachment (RD) (p < 0.001, p < 0.001, p < 0.001 and p = 0.001). Moreover, the stage of RD has a significant correlation with longer AL and shallower anterior chamber depth (ACD) (p = 0.001 and p = 0.034, respectively). (4) Conclusions: A higher incidence and earlier onset of fundus lesions were found in MFS patients. Yearly systematic examination is recommended for MFS children with fundus manifestation until the cardiovascular and skeletal development is complete.

Multicolor Imaging for Detection of Retinal Nerve Fiber Layer Defect in Myopic Eyes With Glaucoma

PURPOSE

To investigate the diagnostic performance of multicolor imaging for detection of retinal nerve fiber layer (RNFL) defects in myopic eyes with glaucoma.

DESIGN

Comparative diagnostic analysis.

METHODS

A total of 150 myopic eyes of 138 patients (< -1.00 diopter or axial length >24 mm) underwent multicolor imaging by Spectralis (Heidelberg Engineering GmbH) optical coherence tomography (OCT). Two independent observers graded the RNFL visibility score and determined the location of the RNFL defect on each image. Readings were taken from the superior and inferior areas. The diagnostic performances of multicolor, green-reflectance, and blue-reflectance images for detection of the RNFL defect were compared with those of conventional fundus and red-free RNFL photographs.

RESULTS

The interobserver agreement on the RNFL visibility score was substantial for fundus and RNFL photographs and multicolor and green-reflectance images and was perfect for blue-reflectance images. The interobserver agreement on the location of the RNFL defect was better when using multicolor imaging than when using conventional photography. The green-reflectance image (2.89 ± 0.31) showed the highest RNFL visibility score, followed by blue-reflectance (2.88 ± 0.32) and multicolor (2.57 ± 0.63) images. The sensitivity of multicolor imaging (94.9%, 93.2%, and 91.5% for green-reflectance, blue-reflectance, and multicolor images, respectively) was significantly higher than that of fundus photography (83.1%) for detection of superotemporal RNFL defects (all P < .05). It was significantly higher for inferotemporal defects than those of fundus and RNFL photographs (all P < .05).

CONCLUSIONS

Multicolor imaging can visualize the glaucomatous RNFL defects in myopic eyes that are indistinguishable on conventional photography.

Visually guided chick ocular length and structural thickness variations assessed by swept-source optical coherence tomography

Chicks are an excellent model for studying myopia. To study the change of the ocular structures in chicks, ultrasound is mostly used. However, it suffers from limited spatial resolution. In this study, we investigated the axial length (AL) and the thickness of different ocular structures in chicks' eye undergoing visually induced changes using a swept-source optical coherence tomography (SS-OCT) system in vivo. Two groups of chicks wore a translucent plastic goggle (n = 6) over the right eye to induce form-deprivation myopia. Following 12 days of form deprivation, goggles were removed in one group of chicks (n = 3), and they were allowed to experience 5 days of unrestricted vision (recovery). Goggles remained in place for a total of 17 days for the remaining 3 chicks. A separate group of 3 chicks were untreated and served as normal control. Ocular dimensions were measured in control, myopic, and recovered eyes using an SS-OCT system. We found myopic chick eyes had significantly thicker AL, lens thickness (LT), anterior chamber depth (ACD), and vitreous chamber depth (VCD), but significantly thinner retina thickness (RT) and choroid thickness (ChT) compared to the control eyes. Following 5 days of recovery, the cornea thickness (CT), retina pigment epithelium thickness (RPET), and ChT were significantly thicker, while the ACD and LT became significantly thinner compared to that of myopic eyes. SS-OCT can serve as a promising tool to provide measurements of the entire ocular structures, for evaluating the change of thickness and depth of different ocular structures in chicks in vivo. The change of AL in the myopic and recovered chick eyes can be attributed to the thickness alterations of different ocular structures. Altogether, this work demonstrated the feasibility of SS-OCT in chick myopic research and exhibited new insights into the changes of ocular structures in chicks experiencing myopia after unrestricted vision recovery.

Factors associated with axial length elongation in high myopia in adults

AIM

To investigate the association of axial length (AL) and ocular factors on AL elongation.

METHODS

A retrospective chart review of patients who underwent two or more AL examinations for more than two years. Totally 4 groups were divided according to initial AL (<24 mm, 24-26 mm, 26-28 mm, ≥28 mm). Initial fundus photograph was used to find risk factors associated AL elongation.

RESULTS

The mean age of the patients was 47.21±7.79y. AL remained almost unchanged in the groups with AL<24 mm and 24≤AL<26 mm. On the contrary, AL increased by 0.011 mm/y in the group with 26≤AL<28 mm and 0.035 mm/y in the group with AL≥28 mm (P<0.001). In high myopia, AL elongation increased in eye with longer AL (r=0.003, P=0.024), female gender (r=0.014, P=0.019), eye with larger peripapillary chorioretinal atrophic area (r=0.002, P=0.019), and smaller vascular arcade angle (r=-0.004, P=0.006). The risk of elongation 0.03 mm/y in high myopia was increased in female gender (P=0.040), and gradually increased in eye with large peripapillary chorioretinal atrophy area (P<0.01).

CONCLUSION

AL elongate significantly in the eye with longer AL, female gender, and the eye with larger atrophic area and smaller arcade angle on fundus photography.

IMI Pathologic Myopia

Pathologic myopia is a major cause of visual impairment worldwide. Pathologic myopia is distinctly different from high myopia. High myopia is a high degree of myopic refractive error, whereas pathologic myopia is defined by a presence of typical complications in the fundus (posterior staphyloma or myopic maculopathy equal to or more serious than diffuse choroidal atrophy). Pathologic myopia often occurs in eyes with high myopia, however its complications especially posterior staphyloma can also occur in eyes without high myopia.

Owing to a recent advance in ocular imaging, an objective and accurate diagnosis of pathologic myopia has become possible. Especially, optical coherence tomography has revealed novel lesions like dome-shaped macula and myopic traction maculopathy. Wide-field optical coherence tomography has succeeded in visualizing the entire extent of large staphylomas. The effectiveness of new therapies for complications have been shown, such as anti-VEGF therapies for myopic macular neovascularization and vitreoretinal surgery for myopic traction maculopathy.

Myopia, especially childhood myopia, has been increasing rapidly in the world. In parallel with an increase in myopia, the prevalence of high myopia has also been increasing. However, it remains unclear whether or not pathologic myopia will increase in parallel with an increase of myopia itself. In addition, it has remained unclear whether genes responsible for pathologic myopia are the same as those for myopia in general, or whether pathologic myopia is genetically different from other myopia.

Longitudinal Changes of Macular Curvature in Patients with Retinitis Pigmentosa

Purpose

To investigate the longitudinal changes of the macular curvature in eyes with retinitis pigmentosa (RP) and to determine the factors associated with the changes.

Methods

We reviewed the medical charts of 107 RP patients, for whom the axial length of their right eyes ranged from 21.5 to 26.0 mm and who had had been followed by spectral-domain optical coherence tomography (OCT). The OCT images at the initial and the most recent examinations were compared. The mean curvature of Bruch's membrane within 6 mm of the central macula obtained from the OCT images was evaluated as the mean macular curvature index (MMCI). Changes in the MMCI and their relationships with other clinical factors, including the ellipsoid zone (EZ) width, were assessed.

Results

The MMCI decreased significantly in the vertical OCT images, from –15.47 × 10⁻⁵ µm⁻¹ to –16.36 × 10⁻⁵ µm⁻¹ (P = 0.008) during the mean observation period of 3.4 ± 1.4 years (mean ± SD). This indicated that the macular shape became more concave. The change to a steeper shape was more prominent in eyes with less photoreceptor degeneration and for which the EZ width was preserved at >2000 µm. In three eyes, the MMCI increased markedly by >5 × 10⁻⁵ µm⁻¹, and this was accompanied by absorption of the macular edema.

Conclusions

The macular curvature in RP eyes becomes more concave in eyes with preserved EZ width.

Translational Relevance

Longitudinal changes of the macular curvature in RP should be considered in future therapies, such as the implantation of the retinal prosthesis.

High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study

PURPOSE

To determine the myopia prevalence in Hong Kong Chinese children and their parents.

METHODS

It was a population-based cross-sectional study. A total of 4257 children aged 6-8 years, and 5880 parents were recruited in the Hong Kong Children Eye Study. Cycloplegic autorefraction was measured for children; and non-cycloplegic autorefraction for parents. Parental educational level, children's outdoor time, and near work were collected by validated questionnaires.

RESULTS

In children aged 6-8 years, 25.0% were myopic, and among them, 12.7% for the 6-year-olds, 24.4% for the 7-year-olds and 36.1% for the 8-year-old. About 0.7% of children aged 8 years were high myopia. In all age groups, boys (their myopia rate: 13.9% at 6 years, 26.7% at 7 years, and 38.3% at 8 years) were more myopic than girls (11.3% at 6 years, 22.0% at 7 years, 33.4% at 8 years). Among parents, 72.2% were myopic (mother, 73.2%; father, 70.7%) and 13.5% high myopia (mother, 12.8%; father, 14.5%). It was observed that prevalence decreased with ages and increased with education level.

CONCLUSION

There is a strikingly high prevalence of myopia in Hong Kong children aged 6-8, much higher than that of other regions of China. Of note, the prevalence of children was similar to that in 15 years ago. Furthermore, the myopia prevalence of parents is high, and it had already increased in this cohort. Prevention of childhood myopia is important, likewise for visual complications from high myopia in adults.

Long-Term Natural Course of Pathologic Myopia in Chinese Patients

Purpose

To investigate the natural progression in Chinese patients with pathological myopia (PM) and its associated factors.

Methods

The medical records of 28 patients with PM (worse than −6 diopter), including 31 eyes of 21 children and 12 eyes of 7 adults, were studied. All of the patients underwent a complete ophthalmologic examination at least twice over 3-year period, including the measurement of refractive error (shown as spherical equivalent, SE), axial length (AL), intraocular pressure, visual acuity (uncorrected visual acuity, UCVA, and best-corrected visual acuity, BCVA), and dilated fundus examination.

Results

The median AL of adults increased significantly from 29.8 mm to 31.43 mm over 5.4 years follow-up (P=0.0037), accompanied with the median SE progressing significantly from −16.4 D to −18.94 D (P=0.0005). Similarly, the median AL of children increased significantly from 26.13 mm to 27.81 mm over 3.9 years (P=0.0001). However, the improvements of UCVA and BCVA in children were significant (P=0.0304, 0.0001), and they had a negative correlation with age (P=0.0010, 0.0005). Also, UCVA and BCVA in children with bilateral PM were significantly better than those with unilateral PM (P=0.0385, 0.0210).

Conclusions

Fundus degenerations in children with pathological myopia may lead its way since the age of 10 years. Besides, children with bilateral pathological myopia can have parallel development in visual acuity.

Choroidal imaging biomarkers

The choroid is the vascular coat of the eye, and its role has been studied in multiple chorioretinal disorders. Recent advancements in choroidal imaging techniques, including enhanced depth imaging optical coherence tomography, swept source optical coherence tomography, en face optical coherence tomography, and optical coherence tomography angiography have facilitated an in-depth analysis of the choroid. The gradual shift from manual to automated segmentation and binarization methods have led to precise and reproducible measurements of choroidal parameters. These qualitative and quantitative parameters, called choroidal imaging biomarkers, have evolved over the past decade from a simple linear subfoveal choroidal thickness to more complex 3D choroidal reconstruction, thus widening the spectrum encompassing multiple parameters. These biomarkers have provided a better understanding of the pathogenesis, are helpful in diagnostic dilemmas, and, in the future may also help to devise treatment options. The lack of normative data, absence of standardized parameters, and limitations of the imaging techniques, however, have led to ambiguity and difficulty in the interpretation of these variables. We attempt to address these lacunae in the literature and provide a basic understanding of the choroid in both health and disease using these choroidal biomarkers.

Clinical histopathology of intrachoroidal splitting in open-globe injury: A retrospective case series of four patients

PURPOSE:

The purpose of this study is to observe the characteristics of intrachoroidal splitting (ICS) associated with choroidal detachment due to open-globe injury.

METHODS:

A retrospective, observational case series study of four eyes diagnosed with choroidal detachment exhibited ICS. The in vivo pathologic changes of the ICS were recorded during surgery. Four specimens were obtained from the inner part of the ICS region. One specimen was stained with hematoxylin and eosin; one specimen was examined under scanning electron microscopy, and the other two specimens were examined under transmission electron microscopy.

RESULTS:

All four patients presented with vortex vein rupture associated with large-scaled mid-peripheral ICS. The histopathologic observations indicated that ICS occurred between the medium-sized and large-sized choroidal vessel layers. Large vascular indentations and medium-sized choroidal vessels were observed on the inner part of the split interface. Postoperative outcomes of the four patients were poor. Vision in all four patients was no light perception before or after surgery. Three eyes became atrophic with silicon oil tamponade and band keratopathy, one eye was eventually enucleated for cosmetic reason.

CONCLUSION:

Intrachoroidal tissue has the potential to split during trauma. The outcome of ICS with choroidal detachment in open-globe injury was poor.

Choroidal and Retinal Thickness of Highly Myopic Eyes with Early Stage of Myopic Chorioretinopathy: Tessellation

Purpose

To investigate the choroidal thickness (CT) and retinal thickness (RT) in highly myopic tessellated eyes.

Methods

In this study, 115 highly myopic eyes were recruited and divided as tessellated fundus (n = 93) and normal fundus (n = 22). RT and CT were quantified using optical coherence tomography with enhanced depth imaging (EDI-OCT). Correlation between subfoveal CT (SFCT) and tessellation was analyzed using logistic regression models.

Results

Tessellated fundus eyes had thinner CT than did normal fundus eyes, while RT was not statistically different across groups. The tessellated eyes had a thinner choroid than did the control eyes at all measured macular locations (all P < 0.05). After adjustment for AL, age, and gender, the SFCT was significantly associated with tessellation. The odds ratio (OR) and 95% confidence interval (CI) was 0.975 (0.960–0.990, P = 0.001, binary logistics regression) and 0.991 (0.984–0.999, P = 0.022, Cox regression). The area under the curve (AUC) of SFCT was the greatest for detecting tessellation (AUC = 0.824, P < 0.001). For sensitivity and specificity analyses, SFCT had the highest diagnostic value (sensitivity = 81.8%, specificity = 74.2%).

Conclusions

Highly myopic eyes with tessellation have thinner CT than do normal highly myopic eyes. CT may serve as an early pathologic predictor of high myopia.

Retinal and Choroidal Thickness in Patients with High Myopia without Maculopathy

Objective

To evaluate macular choroidal thickness (CT) and retinal thickness in Turkish patients with high myopia without maculopathy and in normal subjects and to examine the association with age, axial length (AL), best corrected visual acuity (BCVA), cycloplegic refraction, and spherical equivalent (SE).

Methods

This prospective study was performed between January 2015 and June 2016 in the Department of Ophthalmology, Duzce University Medical Faculty. It had 65 individuals (30 patients with high myopia, 35 healthy subjects). Retinal and choroidal images were obtained using spectral-domain optical coherence tomography (OCT). Measurements (one subfoveal, three temporal, three nasal) were taken at 500 μm intervals up to 1,500 μm using the caliper system. Only the right eye was used for subsequent analysis.

Results

The mean age was 29.5 ± 14.5 years and 25.6 ± 7.0 in the high myopia and control groups, respectively. The subfoveal CT was significantly lower in the high myopia group (mean, 218.3 ± 102.25 mm) than the control group (mean, 331.83 ± 99.06 mm; p < 0.001). In both groups, the choroid was thinnest at the nasal 1,500 μm location, being 158.40 ± 90.8 μm and 301 ± 103.59 μm, respectively. Retinal thickness in both groups was thickest at the nasal 1,500 μm location and thinnest in the subfoveal region. In patients with high myopia, CT was negatively correlated with AL (r=-0.490, p=0.006) and age (r=-0.455, p=0.012).

Conclusions

Highly myopic eyes have a thinner choroid, which may be secondary to longer AL but is not an independent factor. Further studies in the field of OCT are important to exploring the pathology of high myopia.

Understanding the Determinants of Myopic Choroidal Neovascularization and Response to Treatment

Purpose

The pathophysiologic pathways that govern the development of choroidal neovascularization (CNV) are complex. Patchy atrophy and lacquer cracks are known to be major anatomic risk factors for the development of myopic CNV, but they are not alone and much remains to be understood about other factors that influence development. In addition, a greater understanding of the modifiable and nonmodifiable factors that influence outcome, resolution, and recurrence after intravitreal injection of anti-vascular endothelial growth factor (VEGF) could lead to more personalized treatment algorithms that integrate parameters other than the presence of CNV itself and could help improve clinical outcomes and reduce recurrence.

Methods

We reviewed recently published data on risk factors for CNV and predictors of response to anti-VEGF treatments. In particular, data pertaining to age, sex, genetic predisposition, baseline visual acuity, axial length, staphyloma, lacquer cracks, atrophic lesions, choroidal thickness or choroidal thinning, characteristics of CNV such as duration, localization, and size of CNV, and treatment considerations such as choice of treatment, loading doses, and combination treatments were reviewed.

Results

Our analysis showed that the body of evidence is incomplete.

Conclusions

Additional studies are required to identify high-risk patients and to develop personalized therapeutic approaches.

Choroidal thickness and high myopia: a case-control study of young Chinese men in Singapore

PURPOSE

To determine the distribution of choroidal thickness (CT) and ocular factors associated with CT in high myopic eyes in comparison with emmetropic eyes of young healthy adults.

METHODS

A case-control study of 648 young, male subjects, including 520 high myopes and 128 emmetropes. Choroidal imaging was performed using enhanced depth imaging spectral domain optical coherence tomography. Images were postprocessed using adaptive compensation for quality enhancement. CT was measured at nine locations, including subfovea and 1.5 and 3 mm nasal, temporal, superior and inferior to fovea.

RESULTS

The CT at the subfovea was significantly thinner (mean ± standard error: 225.87 ± 5.51 μm) for high myopes compared to emmetropes (375.15 ± 6.58 μm, p < 0.001). Likewise, CT in high myopic group was significantly thinner than emmetropic control group at all locations (p for trend <0.001 for all locations). Distribution of CT showed a markedly different pattern in high myopic eyes (thickest superiorly at 3 mm, 265.97 ± 5.97 μm) and emmetropic eyes (thickest subfoveally, 375.15 ± 6.58 μm). Choroid was thinnest at nasal 3 mm location in both the myopic (108.85 ± 3.97 μm) and emmetropic (238.25 ± 6.72 μm) groups. Among the ocular factors studied, axial length, posterior staphyloma and chorio-retinal atrophy were the significant predictors of CT.

CONCLUSIONS

Highly myopic eyes have significantly thinner choroid and showed different distribution pattern, compared to emmetropes. Axial length, posterior staphyloma and chorio-retinal atrophy are the strongest determinants of CT.

Objective analyses of tessellated fundi and significant correlation between degree of tessellation and choroidal thickness in healthy eyes

A tessellated fundus is a common characteristic of myopic eyes and is an important clinical marker for the development of retinochoroidal changes. However, the exact cause and significance of tessellated fundi have not been definitively determined. We determined the degree of tessellation in fundi objectively in normal, non-pathological myopic eyes, and correlated the degree of tessellation and the choroidal thickness (CT) and axial length (AL). This was a prospective observational cross sectional study. The eyes were classified subjectively into three groups based on the degree of tessellation observed ophthalmoscopically. Digital color fundus photographs were assessed for the degree of tessellation by ImageJ, an image processing program. Three tessellated fundus indices (TFIs) were calculated and were compared to the three subjectively-determined groups. The subfoveal and nasal CTs were measured in the optical coherence tomographic images. The correlations between the TFIs and the CT were calculated. Additionally, the correlation between the TFIs and the AL was calculated. One hundred right eyes of 100 healthy volunteers (mean age 25.8±3.9 years) were studied. Ophthalmoscopically, 57 eyes were placed in the non-tessellated group, 27 eyes into the weakly tessellated group, and 16 eyes into the strongly tessellated group. There was a significant correlation between the subjective classifications and the TFI values (P<0.05, Kruskal-Wallis test). All of the TFIs were significantly associated with the subfoveal and nasal CT (R = -0.20 to -0.24, P<0.05). The TFIs were not significantly correlated with the ALs. In conclusion, the significant correlation between the subjective and objective classifications of the degree of tessellation indicates that TFIs can be used to classify the degree of tessellation. The results indicate that the differences in the CT account for the degree of tessellation.

[Macular choroidal thickness assessment with SD-OCT in high myopia with or without choroidal neovascularization]

PURPOSE

To measure macular choroidal thickness (CT) using spectral-domain optical coherence tomography (SD-OCT) in eyes with myopic macular choroidal neovascularization (CNV), and to compare choroidal thickness in these eyes with highly myopic eyes without CNV.

PATIENTS AND METHODS

Sixty-four eyes with myopic CNV matched with 64 highly myopic eyes without CNV by age and axial length (AL) were examined between January 2010 and November 2011. OCT scans were performed with spectral-domain OCT (TOPCON OCT 2000). The reference position was changed from the vitreous to the choroid. OCT scan patterns consisted of seven sections; the subfoveal CT was measured manually between Bruch's membrane and the internal portion of the sclera in eyes with CNV and from the pigment epithelium to the scleral interface in eyes without CNV.

RESULTS

In the subgroup with CNV, the mean subfoveal CT was 51.71 μm ± 17.35. A statistically significant negative correlation was found between CT and AL (r=-0.615, P=0.0001). Regression analysis demonstrated a decrease of 8.4 μm per mm of AL. In the subgroup without CNV, matched with the CNV subgroup by age (P=0.597), and AL (P=0.813), the mean subfoveal CT was 93.35 μm ± 34.81 μm. The difference between the two subgroups was statistically significant (P<10(-4)).

DISCUSSION

Macular choroidal thickness is reduced in high myopia, especially when complicated by CNV. It has not yet been shown that choroidal thinning may be a risk factor for choroidal neovascularization, but our results may suggest that macular choroidal thinning may lead to hypoxic retinal changes resulting in secretion of VEGF and thus CNV.

CONCLUSION

Macular choroidal thinning observed in high myopia with CNV. These findings may suggest that choroidal changes may play a role in the pathogenesis of choroidal neovascularization.

The relationship between axial length and choroidal thickness in eyes with high myopia

PURPOSE

To investigate the choroidal thickness in highly myopic eyes with no history of choroidal neovascularization or ocular surgery, and to correlate it with axial length, age, and spherical equivalent.

DESIGN

Retrospective, comparative, noninterventional case series.

METHODS

A total of 120 eyes of 83 patients with high myopia (spherical equivalent ≥-6 diopters or axial length ≥26 mm) and 96 eyes of 62 healthy patients were studied in a clinical setting. Eyes with prior vitreoretinal surgery or laser or anti-vascular endothelial growth factor therapy were excluded. Eyes were imaged using optical coherence tomography employing a 6-mm line, reference position "Choroid," and image averaging 50. Choroidal thickness was manually measured from the posterior edge of the retinal pigment epithelium to the choroid-scleral junction at 500-μm intervals up to 2500 μm nasal and temporal to the fovea. Statistical analysis was performed.

RESULTS

The high myopia group mean age was 54.4 ± 18.2 years (range, 18-99) and mean axial length was 29.17 ± 2.44 mm (range, 26.00-35.63). Mean macular choroidal thickness was 115.5 ± 85.3 μm (range, 6.9-436.0). The choroid was thickest temporally (134 μm), then subfoveally (130 μm), and was thinnest in the nasal area (68 μm). This pattern differed markedly from the control eyes. In the high myopia group, axial length had the best correlation with choroidal thickness (r = -0.740; P < .001). Choroidal thickness decreased 25.9 ± 2.1 μm for each additional millimeter.

CONCLUSIONS

Axial length is especially associated with choroidal thickness in high myopia. Choroidal thickness profile in highly myopic patients differs from that in emmetropic patients.

Scleral thickness in highly myopic eyes measured by enhanced depth imaging optical coherence tomography

PURPOSE

The 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.

METHODS

The 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.

RESULTS

A 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).

CONCLUSION

Posterior staphyloma formation was a key factor associated with a posterior scleral thinning in highly myopic eyes.

Peripapillary crescent and related factors in highly myopic healthy eyes

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.