Effects of obstructive sleep apnea on retinal microvasculature.

AIM: To detect retinal microvascular variations in obstructive sleep apnea syndrome patients. METHODS: This prospective, observational case-control study included healthy controls and patients with mild, moderate, and severe obstructive sleep apnea syndrome. Vascular parameters, foveal avascular area, and flow areas in macula-centered, 6.00×6.00 mm2 scan size optical coherence tomography angiography images were compared. RESULTS: The control group had the highest whole image, parafoveal, and perifoveal vessel density among the groups in both superficial and the deep capillary plexus (all P<0.05). Rapid eye movement sleep apnoea-hypopnoea index was reversely correlated with whole (Rho=-0.195, P=0.034), parafoveal (Rho=-0.242, P=0.008), perifoveal (Rho=-0.187, P=0.045) vessel density in the superficial capillary plexus, and whole (Rho=-0.186, P=0.046), parafoveal (Rho=-0.260, P=0.004), perifoveal (Rho=-0.189, P=0.043) vessel density in the deep capillary plexus, though the mean and non-rapid eye movement sleep apnoea-hypopnoea index related with only parafoveal vessel density in the superficial capillary plexus (Rho=-0.213, P=0.020; Rho=-0.191, P=0.038) and the deep capillary plexus (Rho=-0.254, P=0.005; Rho=-0.194, P=0.035). CONCLUSION: This study shows decreased vessel density and its reverse correlation with the apnoea-hypopnoea index in patients with obstructive sleep apnea syndrome.

Optic nerve head vascular variations in pseudoexfoliative and primary open-angle glaucoma.

PURPOSE: The purpose of this study was to assess the optic nerve head microvascular changes in pseudoexfoliative and primary open-angle glaucoma and define the relationship between vessel density and retinal nerve fiber layer thickness. METHODS: This observational cross-sectional study assessed 72 eyes with primary open-angle glaucoma, 41 eyes with pseudoexfoliative glaucoma, and 60 healthy eyes. On the basis of optic nerve head-centered, 4.5 mm × 4.5 mm scan size images, we evaluated the vessel density, as well as the peripapillary sector, inside disk, and all sectoral quadrants. RESULTS: Both glaucoma Groups had lower vessel density in all regions compared with the healthy Group (p<0.05 for all variables). Vessel densities of the nasal inferior, inferior nasal, and inferior temporal sectors in both glaucoma Groups showed similar results (p=0.157, p=0.128, p=0.143, respectively). Eyes with pseudoexfoliative glaucoma had significantly lower vessel densities than eyes with primary open-angle glaucoma in all other regions (p<0.05 for all variables). For both glaucoma Groups, the average retinal nerve fiber layer thickness positively correlated with vessel density in all peripapillary sectors (p<0.05 for all variables). CONCLUSIONS: Reduction in vessel density correlated with the thinning of retinal nerve fiber layer in both glaucoma Groups. Decreased vessel density in the optic nerve head can be used to demonstrate the microvascular pathologies and possible ischemic changes that lead to faster progression and worse prognosis in pseudoexfoliative glaucoma.

Optic nerve head vascular variations in pseudoexfoliative and primary open-angle glaucoma / Variações vasculares da cabeça do nervo óptico no glaucoma pseudoesfoliativo e primário de ângulo aberto

Abstract Purpose: The purpose of this study was to assess the optic nerve head microvascular changes in pseudoexfoliative and primary open-angle glaucoma and define the relationship between vessel density and retinal nerve fiber layer thickness. Methods: This observational cross-sectional study assessed 72 eyes with primary open-angle glaucoma, 41 eyes with pseudoexfoliative glaucoma, and 60 healthy eyes. On the basis of optic nerve head-centered, 4.5 mm × 4.5 mm scan size images, we evaluated the vessel density, as well as the peripapillary sector, inside disk, and all sectoral quadrants. Results: Both glaucoma Groups had lower vessel density in all regions compared with the healthy Group (p<0.05 for all variables). Vessel densities of the nasal inferior, inferior nasal, and inferior temporal sectors in both glaucoma Groups showed similar results (p=0.157, p=0.128, p=0.143, respectively). Eyes with pseudoexfoliative glaucoma had significantly lower vessel densities than eyes with primary open-angle glaucoma in all other regions (p<0.05 for all variables). For both glaucoma Groups, the average retinal nerve fiber layer thickness positively correlated with vessel density in all peripapillary sectors (p<0.05 for all variables). Conclusions: Reduction in vessel density correlated with the thinning of retinal nerve fiber layer in both glaucoma Groups. Decreased vessel density in the optic nerve head can be used to demonstrate the microvascular pathologies and possible ischemic changes that lead to faster progression and worse prognosis in pseudoexfoliative glaucoma.

Resumo Objetivo: Atribuir variações microvasculares à cabeça do nervo óptico no glaucoma pseudoesfoliativo e primário de ângulo aberto, e definir a relação entre a densidade dos vasos e a espessura da camada de fibras nervosas da retina. Métodos: Este estudo foi projetado como observacional e transversal. Foram incluídos 72 olhos com glaucoma primário de ângulo aberto, 41 olhos com glaucoma pseudoesfoliativo e 60 olhos saudáveis. Foram obtidas imagens do nervo óptico centralizadas na cabeça do nervo com 4,5 × 4,5 mm de tamanho de varredura. A densidade vascular foi avaliada em toda a imagem, na área peripapilar, dentro do disco óptico e em todos os quadrantes setoriais. Resultados: Em todas as regiões, a densidade vascular foi menor em ambos os grupos com glaucoma que nos olhos saudáveis (p<0,05 para todas as variáveis). Em ambos os grupos com glaucoma, a densidade vascular mostrou resultados semelhantes nos setores nasal inferior, inferior nasal e temporal inferior (respectivamente, p=0,157, p=0,128 e p=0,143). Os olhos com glaucoma pseudoesfoliativo mostraram densidade vascular acentuadamente menor que nos olhos com glaucoma primário de ângulo aberto em todas as outras regiões (p<0,05). A espessura média da camada de fibras nervosas da retina demonstrou uma correlação positiva com a densidade vascular em todos os setores peripapilares em ambos os grupos com glaucoma (p<0,05 para todas as variáveis). Conclusões: A redução da densidade vascular foi correlacionada a uma redução da espessura da camada de fibras nervosas da retina em ambos os grupos com glaucoma. A densidade vascular reduzida na cabeça do nervo óptico poderia ser usada para provar patologias microvasculares e possíveis alterações isquêmicas responsáveis por uma evolução mais rápida e um prognóstico pior no glaucoma pseudoesfoliativo.

The effect of vitamin D deficiency on the retinal microvasculature: an observational case-control study / O efeito da deficiência de vitamina D nos microvasos da retina: um estudo caso-controle observacional

ABSTRACT Purpose: To determine the effects of vitamin D deficiency on retinal microvascularity using optical coherence tomography angiography. Methods: This study was designed as an observational case-control study. Ninety-eight eyes of patients with vitamin D deficiency and 96 eyes of healthy participants with serum vitamin D level >30 ng/mL were studied. Macula centered, 6.00 × 6.00 mm scan size images were taken. The vessel densities in the superficial and deep retinal capillary plexus, foveal avascular zone area, and choriocapillaris flow area were measured. Results: The groups were comparable in terms of best-corrected visual acuity, sex, axial length, refractive error, age, and adjusted intraocular pressure. The average vitamin D level was significantly lower in the study group (p=0.021). The whole, parafoveal, and perifoveal vessel densities in the deep capillary plexus were considerably higher in the study group than in the control group (p=0.012, p=0.014, and p=0.023, respectively). The foveal avascular zone area and the choriocapillaris flow area were similar in both groups (p=0.37 and p=0.27, respectively) there was a strong negative correlation between the serum vitamin D level and vessel density in the whole image, parafoveal, and perifoveal regions of the deep capillary plexus in the study group (Spearman's rho=-0.71, p=0.043; Spearman's rho= -0.79, p=0.011; and Spearman's rho = -0.74, p=0.032; respectively). Conclusion: An increase in vessel density might originate from vascular structural changes caused by vitamin D deficiency. The increased vessel density, especially in the deep capillary plexus, can enable early diagnosis of vitamin D-associated vasculopathy.

RESUMO Objetivo: Determinar os efeitos da deficiência de vitamina D nos microvasos da retina usando angiotomografia de coerência óptica. Métodos: Este estudo foi planejado para ser do tipo caso-controle observacional. Foram avaliados 98 olhos de pacientes com deficiência de vitamina D e 96 olhos de participantes saudáveis com nível sérico de vitamina D superior a 30 ng/mL. Foram adquiridas imagens de varredura centralizadas na mácula, com um tamanho de 6,00 × 6,00 mm. Mediram-se a densidade dos vasos nos plexos capilares superficial e profundo da retina, a área da zona avascular foveal e a área do fluxo coriocapilar. Resultados: Os grupos mostraram-se semelhantes em relação à melhor acuidade visual corrigida, ao gênero, ao comprimento axial, ao erro refrativo, à idade e à pressão intraocular ajustada. O nível médio de vitamina D foi significativamente menor no grupo de estudo (p=0,021). As densidades total, parafoveal e perifoveal do plexo capilar profundo foram significativamente maiores no grupo de estudo que no grupo controle (respectivamente, p=0,012, p=0,014 e p=0,023). As áreas da zona avascular foveal e do fluxo coriocapilar foram semelhantes nos dois grupos (respectivamente, p=0,37 e p=0,27). Além disso, houve uma forte correlação negativa do nível sérico de vitamina D com as densidades vasculares medidas em toda a imagem e nas regiões parafoveais e perifoveais do plexo capilar profundo no grupo de estudo (respectivamente, ρ de Spearman = −0,71, p=0,043; ρ de Spearman = −0,79, p=0,011; e ρ de Spearman = −0,74, p=0,032). Conclusão: Pode ocorrer um aumento na densidade vascular da retina devido a alterações estruturais dos vasos causadas pela deficiência de vitamina D. O aumento da densidade vascular, especialmente no plexo capilar profundo, pode ser usado para o diagnóstico precoce da vasculopatia associada à deficiência de vitamina D.

The iridocorneal angle and related anterior segment structures in pediatric anisohyperopic amblyopic eyes.

Objectives: We aimed at investigating the iridocorneal angle, anterior segment structural differences, and their relationship in pediatric anisohyperopic amblyopic eyes. Methods: This study was designed as an observational case-control study. We prospectively evaluated the pediatric patients who were newly diagnosed with hyperopic anisometropic amblyopia. Iridocorrneal angle in four sectors, axial length, and anterior segment structures were compared to emmetropic fellow and control eyes using Pentacam and IOLMaster 700 devices. The anisohyperopia and iridocorneal angle related factors were determined in hyperopic anisometropic amblyopic eyes. Results: Forty-three hyperopic anisometropic amblyopic eyes, 43 fellow eyes, and 44 control eyes were included. The mean axial length, anterior chamber volume, and anterior chamber depth were significantly reduced in the study eyes compared to the fellow (p < 0.001, p = 0.021, and p = 0.045, respectively) and control eyes (p < 0.001, p = 0.001, and p = 0.009, respectively). The average iridocorneal angle was significantly lower in the study eyes than in the fellow and control eyes (p < 0.001 and p = 0.018, respectively). The iridocorneal angle correlated with anterior chamber depth (r = 0.49, p = 0.013), anterior chamber volume (r = 0.42, p = 0.038), the anterior radius of curvature (r =-0.54, p = 0.005), the posterior radius of curvature (r =-0.58, p = 0.002), and lens thickness (Rho =-0.41, p = 0.033) in the study eyes. Anisohyperopia was related to the interocular difference in axial length (Rho = 0.53, p = 0.005), anterior chamber depth (Rho = 0.53, p = 0.005), and anterior chamber volume (Rho = 0.42, p = 0.031). Conclusion: Pentacam and IOLMaster 700 are suitable for non-contact imaging of iridocorneal angle and anterior segment structures in the pediatric age. These biometric differences and their relationship should be kept in mind whenever anterior or posterior segment surgery is planned for pediatric anisohyperopic amblyopic eyes.

The effect of vitamin D deficiency on the retinal microvasculature: an observational case-control study.

PURPOSE: To determine the effects of vitamin D deficiency on retinal microvascularity using optical coherence tomography angiography. METHODS: This study was designed as an observational case-control study. Ninety-eight eyes of patients with vitamin D deficiency and 96 eyes of healthy participants with serum vitamin D level >30 ng/mL were studied. Macula centered, 6.00 × 6.00 mm scan size images were taken. The vessel densities in the superficial and deep retinal capillary plexus, foveal avascular zone area, and choriocapillaris flow area were measured. RESULTS: The groups were comparable in terms of best-corrected visual acuity, sex, axial length, refractive error, age, and adjusted intraocular pressure. The average vitamin D level was significantly lower in the study group (p=0.021). The whole, parafoveal, and perifoveal vessel densities in the deep capillary plexus were considerably higher in the study group than in the control group (p=0.012, p=0.014, and p=0.023, respectively). The foveal avascular zone area and the choriocapillaris flow area were similar in both groups (p=0.37 and p=0.27, respectively) there was a strong negative correlation between the serum vitamin D level and vessel density in the whole image, parafoveal, and perifoveal regions of the deep capillary plexus in the study group (Spearman's rho=-0.71, p=0.043; Spearman's rho= -0.79, p=0.011; and Spearman's rho = -0.74, p=0.032; respectively). CONCLUSION: An increase in vessel density might originate from vascular structural changes caused by vitamin D deficiency. The increased vessel density, especially in the deep capillary plexus, can enable early diagnosis of vitamin D-associated vasculopathy.

Microvascular differences in amblyopic subgroups: An observational case-control study.

PURPOSE: To determine retinal microvascular differences among amblyopic subgroups and compare them with control eyes. STUDY DESIGN: This study was designed as an observational case-control study. METHODS: Twenty-three strabismic, 23 anisometropic, 22 meridional, 22 ametropic amblyopic eyes, and 24 healthy control eyes were included. The mean vessel densities in the deep and superficial capillary plexus, the foveal avascular zone area, the choriocapillaris flow area, and the foveal thickness were compared. RESULTS: Vessel density was markedly lower in all sectors of the amblyopic subgroups in the deep capillary plexus than in control eyes. Density was significantly lower in the superficial capillary plexus only in ametropic and meridional amblyopic eyes. Among these groups, the meridional amblyopic eyes had the largest choriocapillaris flow area (p = 0.013) and the lowest vessel density in all sectors (p < 0.001). The foveal avascular zone area was similar in all groups (p = 0.561). The fovea was significantly thicker only in the anisometropic and meridional subgroups than control eyes (p = 0.011, p = 0.001, respectively). The foveal avascular zone area was inversely related to the foveal thickness in all groups. CONCLUSION: Retinal structural and microvascular differences were found among amblyopic subgroups. Optical coherence tomography angiography can noninvasively detect these variations, which may be related to the etiologic factors.

Refractive outcomes of table-mounted and hand-held auto-refractometers in children: an observational cross-sectional study.

BACKGROUND: To compare the refractive results of hand-held and table-mounted autorefractors. METHODS: We designed this study as an observational, cross-sectional study. We compared the mean spheric and cylinder power, spherical equivalent, Jackson cross-cylinder values, determined the limits of agreement (LoA), and evaluated the reliability of two autorefractors. RESULTS: We evaluated 256 eyes of 256 pediatric patients (mean age, 9.12 ± 2.26 years; range, 5-16 years). 49% of the patients were female, and 51% were male. The Nidek HandyRef-K autorefractor measured relatively more astigmatism (P < 0.001) and less hyperopia (P = 0.024). The mean differences and 95% LoA were 0.06 D ± 0.47 D (- 0.82 D to 0.98 D) in spherical power, 0.08 D ± 0.28 D (- 0.47 D to 0.64 D) in cylindrical power, 0.11 D ± 0.47 D (- 0.81 D to 1.01 D) in spherical equivalent, 0.02 D ± 0.36 D (- 0.73 D to 0.69 D) in Jackson cross-cylinder power at 0°, 0.005 D ± 0.54 D (- 1.07 D to 1.06 D) in Jackson cross-cylinder power at 45°. We found the difference within 0.50 D in 244 (95%) eyes for spherical power, in 245 (96%) eyes for cylindrical power, 228 (89%) eyes for spherical equivalent, 224 (87%) eyes for Jackson cross-cylinder power at 0°, 213 (83%) eyes for Jackson cross-cylinder power at 45°. When comparing devices, there were strong correlations for spherical power (Spearman's rho = 0.99, P < 0.001), cylindrical power (Spearman's rho = 0.88, P < 0.001), and spherical equivalent (Spearman's rho = 0.98, P < 0.001). CONCLUSION: Two autorefractors showed clinically applicable agreement limits; excellent reliability for spherical power and spherical equivalent and good reliability for cylindrical power; high positive percent agreement for spherical and cylindrical power, spherical equivalent, Jackson cross-cylinder power at 0°and 45°. These results showed that both devices might be used interchangeably for screening of refractive error in children.

Optic nerve head microvascular changes after phacoemulsification surgery.

BACKGROUND: To determine optic nerve head (ONH) microvascular changes detected by optical coherence tomography angiography (OCTA) and intraocular pressure changes (IOPs) after uncomplicated phacoemulsification surgery. METHODS: The study was designed as a prospective observational study. Twenty-four eyes were included. Eyes with retinal vascular pathology, any type of age-related macular degeneration, IOP more than 21 mmHg, axial length less than 20 mm and more than 24 mm, corneal edema and cataracts that can disrupt images, and history of ocular surgery were excluded. Patients underwent OCTA imaging and IOP measurement preoperatively (baseline) and postoperatively (weeks 1 and 4). Vessel density % (VD) in the total disc, peripapillary, and inside disc were measured. IOP was measured with the applanation tonometer. Comparison of VD and IOP and correlation between VD and IOP change were determined. RESULTS: VD was significantly increased in all quadrants in week 4 compared to those in week 1. In terms of VD and IOP, although there was no significant difference between week 1 and baseline, week 4 results were significantly different from baseline (p < 0.05 and p < 0.001, respectively). The IOP was significantly lower in week 4 (14.8 mmHg) than in week 1 (16.0 mmHg) (p < 0.001). There was a significant negative correlation between the inside disc and total VD and IOP at weeks 1 and 4. CONCLUSION: Phacoemulsification surgery can result in a decrease in IOP and an increase in VD of the ONH.

Microvascular changes in amblyopic eyes detected by optical coherence tomography angiography.

PURPOSE: To investigate retinal microvascular findings detected by optical coherence tomography angiography (OCT-A) in amblyopic eyes compared with normal eyes. METHODS: A total of 23 amblyopic (strabismic, ametropic, anisometropic, and meridional amblyopia) and 22 normal eyes were included in this prospective observational, comparative study. All patients underwent complete ophthalmological examination and OCT-A imaging. Vessel density (VD) percentage in the superficial and deep retinal vessel plexus, foveal avascular zone (FAZ) area, flow area in the outer retina and choriocapillaris, and retinal thickness in µm in a 6.00 × 6.00 mm scan size were measured and compared between groups. RESULTS: There were no statistically significant differences between groups in terms of age (P = 0.584) and sex (P = 0.661). Mean FAZ area was smaller in the amblyopic group; however, the difference was not statistically significant (P = 0.145). The outer retina flow area was significantly wider in the amblyopic group (P = 0.03). The fovea was thicker in the amblyopic group (P = 0.02). In addition, VD in both the superficial and deep retinal plexus was significantly lower in amblyopic eyes in all quadrants except the fovea. In amblyopic subgroups, VD of anisometropic amblyopic eyes was significantly higher than other subgroups in both superficial and deep retinal plexuses at all regions except the fovea. Other measures were similar in between groups. CONCLUSIONS: Microvascular retinal structural anomalies detectable on OCT-A could shed further light on the causes of amblyopia.