Comparative analysis of changes in retinal layer thickness following femtosecond laser-assisted cataract surgery and conventional cataract surgery.

BACKGROUND: To investigate the influence of femtosecond laser-assisted cataract surgery (FLACS) on macula by examining changes in retinal layers after FLACS and to compare these changes with those after conventional cataract surgery (CCS). METHODS: This study included 113 unrelated Korean patients with age-related cataract who underwent CCS or FLACS in Severance Hospital between September 2019 and July 2021. Optical coherence tomography was performed before and 1 month after surgery. The total retinal layer (TRL) was separated into the inner retinal layer (IRL) and outer retinal layer (ORL); moreover, the IRL was subdivided into the retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer (INL), outer plexiform layer, and outer nuclear layer. We performed between-group comparisons of the postoperative thickness in each retinal layer and the postoperative differences in retinal thickness. The average retinal thickness of the four inner macular ring quadrants was used for comparative analysis. RESULTS: Compared with the CCS group, the FLACS group exhibited a thicker ORL (P = 0.004) and a thinner INL (P = 0.007) after surgery. All retinal layer thickness values showed significant postoperative changes regardless of the type of surgery (P < 0.05). The postoperative increase in TRL and IRL thickness was significantly smaller in the FLACS group than in the CCS group (P = 0.027, P = 0.012). CONCLUSIONS: The 1-month postoperative retinal changes were less pronounced in the FLACS group than in the CCS group.

Longitudinal changes in each retinal layer thickness in patients with non-ischemic central retinal vein occlusion.

BACKGROUND: To identify longitudinal changes in each retinal layer thickness in central retinal vein occlusion (CRVO) patients with resolved macular edema (ME). METHODS: In this retrospective observational study, CRVO patients without a recurrence of ME for more than 3 years and normal controls were enrolled. Each retinal layer thickness of the parafoveal area, including ganglion cell complex (GCC), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor layer (PRL), and retinal pigment epithelium (RPE) was measured. After the resolution of ME, three more examinations with a 1-year interval were analyzed. RESULTS: A total of 98 eyes were enrolled, 50 eyes for the control group and 48 eyes for the CRVO group. The baseline GCC thickness was 114.2 ± 15.6 µm and 104.2 ± 25.4 µm in the control and CRVO groups, respectively, which was significantly different (P = 0.022). The thicknesses of other layers including INL, OPL, ONL, PRL, and RPE were not significantly different at baseline. The reduction rate of GCC, INL, OPL, and ONL was - 3.92, - 1.33, - 0.91, and - 2.31 µm/year in the CRVO group, whereas no significant reductions were observed in the control group. Best-corrected visual acuity was significantly associated with changes in the GCC, OPL, and ONL in the CRVO group. CONCLUSIONS: In patients with CRVO, even in the absence of recurrent ME, retinal damage progresses over time, evidenced by thinning of the inner retina and outer retina including OPL and ONL. These changes may be associated with alterations in visual function.

Glucose tolerance and insulin resistance/sensitivity associate with retinal layer characteristics: the LIFE-Adult-Study.

AIMS/HYPOTHESIS: As the prevalence of insulin resistance and glucose intolerance is increasing throughout the world, diabetes-induced eye diseases are a global health burden. We aim to identify distinct optical bands which are closely related to insulin and glucose metabolism, using non-invasive, high-resolution spectral domain optical coherence tomography (SD-OCT) in a large, population-based dataset. METHODS: The LIFE-Adult-Study randomly selected 10,000 participants from the population registry of Leipzig, Germany. Cross-sectional, standardised phenotyping included the assessment of various metabolic risk markers and ocular imaging, such as SD-OCT-derived thicknesses of ten optical bands of the retina. Global and Early Treatment Diabetic Retinopathy Study (ETDRS) subfield-specific optical retinal layer thicknesses were investigated in 7384 healthy eyes of 7384 participants from the LIFE-Adult-Study stratified by normal glucose tolerance, prediabetes (impaired fasting glucose and/or impaired glucose tolerance and/or HbA1c 5.7-6.4% [39-47 mmol/mol]) and diabetes. The association of optical retinal band characteristics with different indices of glucose tolerance (e.g. fasting glucose, area under the glucose curve), insulin resistance (e.g. HOMA2-IR, triglyceride glucose index), or insulin sensitivity (e.g. estimated glucose disposal rate [eGDR], Stumvoll metabolic clearance rate) was determined using multivariable linear regression analyses for the individual markers adjusted for age, sex and refraction. Various sensitivity analyses were performed to validate the observed findings. RESULTS: In the study cohort, nine out of ten optical bands of the retina showed significant sex- and glucose tolerance-dependent differences in band thicknesses. Multivariable linear regression analyses revealed a significant, independent, and inverse association between markers of glucose intolerance and insulin resistance (e.g. HOMA2-IR) with the thickness of the optical bands representing the anatomical retinal outer nuclear layer (ONL, standardised ß=-0.096; p<0.001 for HOMA2-IR) and myoid zone (MZ; ß=-0.096; p<0.001 for HOMA2-IR) of the photoreceptors. Conversely, markers of insulin sensitivity (e.g. eGDR) positively and independently associated with ONL (ß=0.090; p<0.001 for eGDR) and MZ (ß=0.133; p<0.001 for eGDR) band thicknesses. These global associations were confirmed in ETDRS subfield-specific analyses. Sensitivity analyses further validated our findings when physical activity, neuroanatomical cell/tissue types and ETDRS subfield categories were investigated after stratifying the cohort by glucose homeostasis. CONCLUSIONS/INTERPRETATION: An impaired glucose homeostasis associates with a thinning of the optical bands of retinal ONL and photoreceptor MZ. Changes in ONL and MZ thicknesses might predict early metabolic retinal alterations in diabetes.

Correlation between different retinal layers with visual acuity in diabetic retinopathy patients with clinically significant macular edema.

Purpose: To study the corelation between outer retinal layer thickness (ORL), outer photoreceptor segment thickness (PROS), and central macular thickness (CMT) with best-corrected visual acuity (BCVA) in patients having clinically significant macular edema (CSME) and compare these parameters with normal patients. Methods: This was a prospective, nonrandomized, observational, comparative study done during the period of January to May 2019. The study included 60 eyes of 36 patients. The patient population was segregated into two Groups: Group I (30 normal eyes of 15 normal patients) and Group II (30 eyes of 21 diabetic patients) with CSME. The comparison between ORL, PROS, and CMT was made between both the groups, and the correlation between ORL thickness, PROS thickness, and CMT with BCVA in Group II was studied. Results: The mean age in Group I was 52.6+10.66 years, and 53.42+8.15 years in Group II. The male/female ratio was 1.1:1 in Group I and 4:3 in Group II. The mean CMT was greater in Group II (330.13 ± 37.01) than in Group I (222.20 ± 12.30). The mean ORL thickness was greater in Group I (97.73 ± 6.92) than in Group II (80.63 ± 9.03). The PROS thickness was statistically significant in Group I (35.05 ± 3.4) than in Group II (28.57 ± 3.53). There was a strong correlation between BCVA and ORL thickness (r = -0.580, P < 0.001) and more strong correlation between BCVA and PROS thickness in Group II (r = -0.611, P < 0.000). There was a moderate correlation between BCVA and CMT (r = 0.410, P < 0.025), and all results were statistically significant. Conclusion: Both ORL and PROS thickness were greater in healthy normal eyes than in eyes with CSME. BCVA was strongly correlated with PROS and ORL thickness and moderately associated with CMT.

The quantitative evaluation of retinal layers after resolution of subretinal fluid in acute central serous chorioretinopathy.

PURPOSE: To evaluate the average retinal layer thicknesses in eyes with unilateral acute central serous chorioretinopathy (CSC) (with subretinal fluid (SRF)) and after complete resolution of SRF in these eyes and to compare the results with those obtained in healthy eyes. METHODS: Fifty-four eyes of 27 patients with unilateral acute CSC (CSC in active phase) who had complete resolution of SRF and 25 eyes of 25 healthy control subjects enrolled in this retrospective study. The average thicknesses of the retinal layers were measured by segmentation analysis of optical coherence tomography at baseline and 6 months after complete resolution of SRF. RESULTS: The mean outer nuclear layer (ONL) thickness was significantly lower in eyes with CSC than in fellow eyes (p < 0.001). The mean ONL thickness was increased after resolution of SRF, but still low compared to unaffected fellow eye and the increment was not statistically significant (p > 0.05). There were significant strong inverse correlations between visual acuity and ONL thicknesses at baseline and 6 months after complete resolution of SRF (p < 0.001, r = - 0.810; p < 0.001, r = - 0.705, respectively). CONCLUSION: ONL thickness was thinned in cases with acute CSC, and although there was some increment in ONL thickness 6 months after complete resolution of SRF, it was still thinner compared to unaffected fellow eyes.

Hydroxychloroquine treatment alters retinal layers and choroid without apparent toxicity in optical coherence tomography.

Background To investigate whether single retinal layer, choroidal and peripapillary retinal fiber layer thicknesses were affected in patients under hydroxychloroquine treatment without retinal toxicity Methods Forty-nine patients under hydroxychloroquine treatment (HCQ group) and 39 healthy volunteers, a total of 88 individuals, were included in the study. Patients with HCQ treatment were further divided into two groups as less than 5 years of HCQ use (group 1, 29 patients) and 5 years or more of HCQ use (group 2, 20 patients). All participants underwent full ophthalmologic examination and optical coherence tomography (OCT) imaging as OCT is a recommended tool for screening toxicity by the American Association of Ophthalmology. The automatic segmentation of retinal layers included retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retina pigment epithelium (RPE), inner retinal layers (IRL), outer retinal layers (ORL) and total retina thickness (TRT). Choroidal thickness (ChT), choroidal vascularity index and peripapillary RNFL were also measured. Results Both inferior and nasal parafoveal RNFL, temporal parafoveal GCL, and IPL layer thicknesses were decreased, while temporal parafoveal RPE layer thicknesses were increased in hydroxychloroquine users. Subfoveal ChTs were significantly reduced in both groups 1 and 2 compared to the control group(p = 0.042 and p = 0.009, respectively) and temporal ChT thicknesses were statistically decreased in group 2 compared to the control group(p = 0.018), but not for nasal ChT. Conclusions Hydroxychloroquine use may cause parafoveal retinal layer thickness alterations and also subfoveal and parafoveal ChT alterations even without evident retinal toxicity in OCT.

Does outer retinal layer thickness correlate with the central visual field indices in early dry age-related macular degeneration?

PURPOSE: Age-related macular degeneration (ARMD) is the leading cause of irreversible blindness worldwide and Nepal is one among them. We aimed to determine the relationship between outer retinal layer thickness parameters with central visual field indices in early dry ARMD cases among Nepalese population. MATERIALS AND METHODS: The subjects for this descriptive, cross-sectional study comprised 40 patients with early dry ARMD from the ophthalmology department of a tertiary level hospital of Nepal. The retinal layer thickness was measured with spectral-domain optical coherence tomography (SD-OCT), and the visual field indices were assessed using the 10-2 protocol of Humphrey visual field analyzer (HFA). Thus, the retinal layer structures correlated with visual field indices among our population. RESULTS: Among our early dry ARMD population, the foveal threshold (FT) was found to be significantly correlated with retinal pigment epithelium (RPE) elevation (P < 0.01, r = -0.541), outer segment (OS) length (P = 0.02, r = 0.465), and inner segment ellipsoid (ISe) band disruption (P = 0.01, r = -0.499), but not with presence of hyperreflective foci (P = 0.464), RPE thickness (P = 0.612), and central macular thickness (P = 0.214). However, no significant correlation between mean deviation and pattern standard deviation of visual field with retinal layer thickness parameters was identified. CONCLUSION: In early dry ARMD, a reduced FT is significantly correlated with the integrity of the ISe band, thinning of OS length, and drusen-associated RPE elevation. The results highlight the utility of both SD-OCT retinal layer measurement and central visual field testing by HFA in ARMD to monitor the progression of the disease.

Evaluation of the change in retinal thickness after femtosecond laser-assisted laser in situ keratomileusis and photorefractive keratectomy.

PURPOSE OF THE STUDY: To investigate the change in individual retinal layer thickness by spectral-domain optical coherence tomography (SD-OCT) in eyes underwent femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and photorefractive keratectomy (PRK). METHODS: In patients who underwent PRK and FS-LASIK, changes in the thickness of all retinal layers in the foveal, parafoveal, and perifoveal regions were evaluated by SD-OCT automated segmentation analysis at pre-operatively and different time points post-operatively. RESULTS: Seventy-one eyes of 71 patients (38 patients in PRK, 33 patients in LASIK) were included. In the pre-operative period, mean spherical equivalent (SE), mean keratometry, axial length, and segmentation values of the retinal layers were similar (P> .05). In the PRK group, the pre-operative measurements of individual retinal layers did not show a statistically significant difference compared to the post-operative measurements on the 1st day, 1st week, and 1st month. In the FS-LASIK group, the mean inner nuclear layer (INL) thickness one day after the surgery was significantly higher than that before surgery in the foveal (21.22 ± 4.66 µm vs 19.03 ± 4.50 µm, P= .013) and parafoveal regions (41.98 ± 3.70 µm vs 40.56 ± 3.49 µm, P= .044). CONCLUSIONS: The findings of our study suggest that the increase of INL thickness may be due to temporary structural and circulatory changes of the retina that may occur in the suction phase in the FS-LASIK procedure.

The effect of silicone oil tamponade on retinal layers and choroidal thickness in patients with rhegmatogenous retinal detachment: a systematic review and meta-analysis.

BACKGROUND: To evaluate the effects of intravitreal silicone oil (SO) on the retinal and choroidal thickness in eyes with rhegmatogenous retinal detachment (RRD). METHODS: A literature search was performed in Web of Science, Scopus, ProQuest, Embase, Clinical Key, Science Direct, Cochrane Library, and Springer, as well as Persian databases, including IranDoc, MagIran, SID, MOH thesis, and MOH articles until June 2020. Two reviewers independently searched and extracted the data. RESULTS: Sixteen studies (n = 391) met the inclusion criteria. The meta-analysis showed that the SO tamponade could significantly reduce the central macular thickness (CMT) in patients with RRD as compared to gas tamponade WMD = - 14.91; 95% CI: - 22.23, - 7.60; P < 0.001, I2 = 71%). No significant change was found in CMT between the eye with SO tamponade (after SO removal) and the fellow healthy eye in patients with RRD (WMD = - 3.52; 95% CI: - 17.63, 10.59; I2 = 68.6%). Compared to the preoperative stage, the SO tamponade could significantly reduce the subfoveal choroidal thickness in patients with RRD (WMD = - 18.67, 95% CI: - 30.07, - 1.28; I2 = 80.1%). However, there was no significant difference in the subfoveal choroidal thickness before and after SO removal (WMD = - 1.13, 95% CI: - 5.97, 3.71; I2 = 87.6%). CONCLUSION: The SO tamponade had a significant effect on the reduction of retinal layers and the subfoveal choroidal thickness.

Reduced macular thickness and macular vessel density in early-treated adult patients with PKU.

PURPOSE: Macular structure is poorly evaluated in early-treated phenylketonuria (ETPKU). To evaluate potential changes, we aimed to examine retinas of PKU patients using optical coherence tomography (OCT) with additional OCT angiography (OCTA) and compare the results to healthy controls. METHODS: A total of 100 adults were recruited in this monocentric, case-control study: 50 patients with ETPKU (mean age: 30.66 ± 8.00 years) and 50 healthy controls (mean age: 30.45 ± 7.18 years). Macular thickness, vessel density and flow area of the right eye was assessed with spectral domain OCT angiography SD-OCT(A). Macular microstructural data between the ETPKU and control group was compared. In the ETPKU group, the relationship between visual functional parameters (best corrected visual acuity [VA], spherical equivalent [SE], contrast sensitivity [CS] and near stereoacuity) and microstructural alterations was examined. The dependency of OCT(A) values on serum phenylalanine (Phe) level was analysed. RESULTS: There was significant average parafoveal and perifoveal total retinal layer thinning in ETPKU patients compared to healthy controls (p < 0.016 and p < 0.001, respectively), while the foveal region remained unchanged in the ETPKU group. Whole macular and parafoveal superficial capillary plexus density was significantly decreased in ETPKU compared to controls (p < 0.001). There were no significant differences in the foveal avascular zone, nonflow area, macular superficial and deep capillary plexus between the groups. The temporal parafoveal inner retinal layer thickness was found to negatively correlate with individual Phe levels (r = -0.35, p = 0.042). There was no difference in vascular density and retinal thickness in the subgroup analysis of patients with good therapy adherence compared to patients on a relaxed diet. CONCLUSIONS: Durable elevation in Phe levels are only partially associated with macular retinal structural changes. However, therapy adherence might not influence these ophthalmological complications.

The Relationship Between Keratoconus Stage and the Thickness of the Retinal Layers

Objectives: To examine the relationship between keratoconus (KC) stage and the thickness of the retinal layers. Materials and Methods: Retinal layer thicknesses were compared between 85 eyes of 85 KC patients and 40 eyes of 40 controls similar in age, sex, and axial length. KC patients were staged as stage 1, 2, or 3 according to the Amsler-Krumeich staging system, and segmentation of the retinal layers was performed with spectral domain optical coherence tomography automatic segmentation program. The thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), and retinal pigment epithelium (RPE) in the central 1 mm Early Treatment Diabetic Retinopathy Study subfield was analyzed. Results: There was no significant difference between the control and KC groups in the segmentation of the RNFL, GCL, IPL, or OPL (p=0.306; p=0.661; p=0.893, p=0.664, respectively). The INL differed significantly between control and stage 2 KC, control and stage 3 KC, stage 1 and 2 KC, and stage 2 and 3 KC, increasing in thickness with higher stage (p=0.004; p=0.005: p=0.001; p=0.002, respectively). The RPE also differed significantly between control and stage 2 KC, control and stage 3 KC, stage 1 and 2 KC, and stage 2 and 3 KC, showing decreased thickness with higher stage (p=0.03; p=0.001; p=0.001; p<0.001, respectively). The ONL also thinned as stage increased, but the results were not statistically significant (p=0.051). Conclusion: More advanced KC stage was associated with increased thickness of the INL layer, where the neuroglial cell bodies are located, and decreased thickness in the outer retinal layers, especially the RPE.

Effects of different tamponade materials on macular segmentation after retinal detachment repair.

PURPOSE: This study used spectral domain-optical coherence tomography (SD-OCT) to evaluate individual retinal layer thickness in eyes with macula-off rhegmatogenous retinal detachment (RRD) treated with silicone oil (SiO) or gas endotamponades. STUDY DESIGN: This was a retrospective, interventional, comparative study. METHODS: The study included 86 eyes of 43 patients who were divided into 3 groups according to endotamponades: SiO, perfluoropropane (C3F8), and sulfur hexafluoride (SF6). The affected eyes were compared with the fellow eyes of the same patient via SD-OCT automated segmentation analysis. Patients with a follow-up of at least 6 months were included in the final analysis. Macular segmentation including the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE), inner retinal layers (IRLs), and outer retinal layers (ORLs) was analyzed. RESULTS: In the SiO group, the mean thickness of each retinal layer including the RNFL, GCL, IPL, ONL, and IRLs within a 1-mm ETDRS subfield of the affected eyes was significantly lower than that of the fellow eyes (P = 0.036, P = 0.028, P = 0.003, P < 0.001, P = 0.013, respectively). There was no significant difference in the C3F8 and SF6 groups (all P > 0.05). The difference between the ONL and IRLs in the SiO-treated eyes differed significantly from that of the gas groups (P = 0.001 and P = 0.045, respectively) The difference in the GCL thickness of the affected eyes and healthy eyes showed a significant correlation with postoperative BCVA changes in the SiO, C3F8, and SF6 groups (P = 0.041, P = 0.048, and P = 0.045, respectively). CONCLUSION: The findings of our study show that endotamponades used in RRD surgery may have different effects on retinal layers. In addition, SiO may cause undesirable effects on the retinal layers.

Microperimetry and Optical Coherence Tomography Changes in Type-1 Diabetes Mellitus without Retinopathy.

BACKGROUND: We aimed to measure and correlate inner retinal layer (IRL) thickness and macular sensitivity by optical coherence tomography (OCT) and by microperimetry, respectively, in type 1 diabetes mellitus patients (DM1) without diabetic retinopathy (DR). METHODS: Fifty-one DM1 patients and 81 age-matched healthy subjects underwent measurement of the axial length (AL), retinal thickness in the macular ETDRS areas by swept source (SS)-OCT and macular sensitivity by microperimeter. RESULTS: The total retinal and IRL thicknesses were thicker in the DM1 group (p < 0.05) in practically all ETDRS areas, and they had a generalized decrease in sensitivity (p < 0.05) in 9 areas between both groups. There was a significant negative correlation between retinal sensitivity and age in all areas and in visual acuity (VA) in 5 out of the 9 areas for DM1 patients. Only a mild negative correlation was observed between retinal sensitivity in the 5° nasal inner (5NI) area and in IRL thickness in the temporal inner (TI) area (-0.309 with p = 0.029) in the DM1 group. CONCLUSION: Aging and disease evolution in DM1 patients without DR signs generate a decrease in retinal sensitivity. There was a direct relationship between retinal sensitivity and macular thickness in the DM1 group.

Retinal structural changes in preterm children without retinopathy of prematurity.

PURPOSE: The aim of this study was to compare all retinal layers' thickness in full-term and preterm children without retinopathy of prematurity (ROP). METHODS: Cross-sectional study including two groups of patients: group 1 children with history of preterm gestation without ROP (gestational age < 37 weeks) and group 2 healthy children with history of full-term gestation. All subjects underwent an ophthalmic examination including spectral domain-optical coherence tomography. After automatic retinal segmentation, each retinal layer thickness (eight separate layers and overall thickness) was calculated in all nine Early Treatment Diabetic Retinopathy Study areas. Demographic, systemic, gestational, and birth data were collected. Generalized additive regression models were used to analyze the data. RESULTS: Fifty-one children (51 eyes) were recruited, 19 full-term and 32 preterm children, mean age at ophthalmic examination of 10.58 (4.21) and 14.13 (3.16), respectively. In multivariable analysis, the preterm group's retinal thickness was significantly decreased in total retina nasal outer sector, ganglion cell layer (GCL), and inner plexiform layer (IPL), specifically GCL temporal outer (p = 0.010), GCL superior outer (p = 0.009), IPL temporal outer (p = 0.022), and IPL superior outer (p = 0.004), when compared with full-term group. From the variables compared only with birth head circumference that influenced the models, a non-linear association was identified and consequently modeled with splines through a generalized additive model. CONCLUSION: This study suggests that preterm children without ROP have structural retinal alterations, mostly in GCL and IPL in outer areas of the macula. Therefore, it is crucial to question gestational history since these retinal changes may be found later in life leading to useless investigation.

Comparison of Retinal Layer Thicknesses of Highly Myopic Eyes and Normal Eyes.

PURPOSE: To evaluate the differences in individual segmental retinal layer thickness in adult patients with high myopia. METHODS: This study compared the retinal layers of patients with high myopia (axial length of ≥26.0 mm) with those of normal controls using spectral-domain optical coherence tomography. The thicknesses of the retinal layers were compared using nine Early Treatment Diabetic Retinopathy Study subfields. Choroidal thickness was also measured in the subfoveal area. RESULTS: We included 37 eyes with high myopia and 37 eyes of healthy subjects. The mean age was 42.95 and 47.73 years (p = 0.114), and the mean axial length was 27.28 and 24.47 mm (p < 0.001), respectively. The parafoveal areas (outer ring segment) of the ganglion cell layer and inner plexiform layer, all segmental areas except the subfoveal region of the inner nuclear layer, most segmental areas (inner superior, inner inferior, outer superior, outer temporal, and outer nasal) of outer plexiform layer, and most segmental areas (subfovea, inner temporal, inner inferior, inner nasal, outer temporal, and outer inferior) of outer nuclear layer were thinner in eyes with high myopia than in normal eyes (all p < 0.05). There were no statistically significant differences between the levels of photoreceptor layer, retinal pigment epithelium, and nerve fiber layer. The mean choroidal thickness was 153.81 ± 64.80 and 239.54 ± 44.28 µm in the high myopia and control groups, respectively, which were significantly different (p < 0.001). CONCLUSIONS: In high myopia without pathologic changes, there was a meaningful thinning of the retina and choroid, especially in most Early Treatment Diabetic Retinopathy Study subfield areas of the deep vascular complex, perifoveal area of the superficial vascular complex, and most areas of the outer nuclear layer in the outer retinal layer, which are associated with myopic axial elongation.

Association between individual retinal layer thickness and visual acuity in patients with epiretinal membrane: a pilot study.

PURPOSE: We investigated the correlation between visual acuity (VA) and individual retinal layer thickness in the foveal, parafoveal, and perifoveal regions of patients with an idiopathic epiretinal membrane (ERM). METHODS: One hundred and five subjects presenting with unilateral idiopathic ERM were included in this study. We segmented each patient's optical coherence tomography (OCT) image into seven layers and calculated the mean layer thickness in the foveal, parafoveal, and perifoveal regions using the Iowa Reference Algorithm. In 105 patients with ERM, we detected correlations between their macular regions' individual retinal layer thickness and their best corrected VA. Thirty-one of the 105 patients with ERM underwent vitrectomy and completed six months of follow-up. We then compared the 31 surgical patients' preoperative and postoperative individual retinal layer thickness in each macular region. Additionally, the association between preoperative individual retinal layer thickness in each macular region and VA six months post-surgery in patients with ≥ two Snellen lines of visual improvement was determined. RESULTS: Multiple linear regression analysis showed that the inner nuclear layer (INL) thickness in the foveal, parafoveal, and perifoveal region were all associated with VA in the 105 patients (R 2 = 0.344, P < 0.001; R 2 = 0.427, P < 0.001; and R 2 = 0.340, P < 0.001, respectively). Thirty-one surgical patients 6 months post-surgery showed significantly decreased thicknesses (P ≤ 0.012) of the foveal INL, inner plexiform layer (IPL), and outer nuclear layer (ONL); the parafoveal retina nerve fiber layer (RNFL), IPL, INL, and ONL; and the perifoveal RNFL, IPL, INL, ganglion cell layer (GCL), outer plexiform layer (OPL), and photoreceptor layer (PRL). We found a weak correlation between postoperative VA and preoperative foveal and perifoveal RNFL thickness (r = 0.404 and r = 0.359, respectively), and a moderate correlation between postoperative VA and preoperative foveal and parafoveal INL thickness (r = 0.529 and r = 0.583, respectively) in the 31 surgical patients (P ≤ 0.047). The preoperative INL thickness in the foveal, parafoveal, and perifoveal regions showed a moderate to strong correlation (r = 0.507, 0.644, and 0.548, respectively), with postoperative VA in patients with ≥ 2 lines of visual improvement (P ≤ 0.038). CONCLUSION: We detected a correlation between retinal damage and VA in the parafoveal, perifoveal, and foveal regions. Our results suggest that INL thickness in all macular regions may be a prognostic factor for postoperative VA in ERM patients.

Comparison of the Iowa Reference Algorithm to the Heidelberg Spectralis optical coherence tomography segmentation algorithm.

For spectral-domain optical coherence tomography (SD-OCT) studies of neurodegeneration, it is important to understand how segmentation algorithms differ in retinal layer thickness measurements, segmentation error locations and the impact of manual correction. Using macular SD-OCT images of frontotemporal degeneration patients and controls, we compare the individual and aggregate retinal layer thickness measurements provided by two commonly used algorithms, the Iowa Reference Algorithm and Heidelberg Spectralis, with manual correction of significant segmentation errors. We demonstrate small differences of most retinal layer thickness measurements between these algorithms. Outer sectors of the Early Treatment Diabetic Retinopathy Study grid require a greater percent of eyes to be corrected than inner sectors of the retinal nerve fiber layer (RNFL). Manual corrections affect thickness measurements mildly, resulting in at most a 5% change in RNFL thickness. Our findings can inform researchers how to best use different segmentation algorithms when comparing retinal layer thicknesses.

Comparison of Retinal Layer Thickness and Vascular Density between Acute and Chronic Branch Retinal Vein Occlusion.

PURPOSE: To compare retinal layer thickness and chorioretinal vascular density (VD) between acute and chronic branch retinal vein occlusion (BRVO). METHODS: This study included patients with BRVO. The VD of the superficial capillary plexus (VDs), the VD of the deep capillary plexus (VDd), and VD of the choriocapillaris were obtained using optical coherence tomography angiography. Acute and chronic BRVO data were compared to assess differences between the involved and uninvolved areas. RESULTS: We included 17 eyes with acute BRVO and 23 eyes with chronic BRVO. The VDs in the involved area were not significantly different between the involved area and in the uninvolved area in acute BRVO (p = 0.551). However, the difference was significant in chronic BRVO (p = 0.013). The VDd in the involved area was lower than in the uninvolved area in both acute and chronic BRVO (p = 0.020, p = 0.003, respectively). In addition, the VD of the choriocapillaris values did not differ significantly between acute and chronic BRVO, or between involved and uninvolved areas. The VDs in the involved area in chronic BRVO were lower than in acute BRVO (p = 0.047), and the VDd did not differ between acute and chronic BRVO in all areas. CONCLUSIONS: Vascular impaired patterns in the retinal layer differed between acute and chronic BRVO. These results may suggest that vascular change and remodeling develops differently in acute and chronic phases in BRVO.

Correlation of retinal layer changes with vision gain in diabetic macular edema during conbercept treatment.

BACKGROUNDS: To assess the changes in individual retinal layer thickness and visual function associated with gains in visual acuity after an intravitreal conbercept injection in the diabetic macular edema (DME) on spectral domain optical coherence tomography (SD-OCT) and microperimetry during 1-year follow-up. METHODS: Retrospective observational study. Twenty patients with clinically significant DME in the study eye were imaged by SD-OCT every 3 months and MP1 microperimeter in the third month while receiving anti-vascular endothelial growth factor (VEGF) (conbercept) treatment. In each patient, seven retinal layers were segmented in 98 scans covering a 6 mm × 6 mm area of the macula at baseline and during 1 year of treatment. An automatic, full-threshold microperimetry of the central field (10° × 10°, 40 stimulated points) with the MP1 microperimeter. Thickness and microperimetry changes were quantitatively measured and evaluated for their correlation with increases in visual acuity. RESULTS: Although thicknesses of the inner nuclear layer (INL) and the outer nuclear layer (ONL) were reduced the most after treatment (p < 0.05), decreases of the ganglion cell layer (GCL) (r = 0.591, p = 0.006) and inner plexiform layer (IPL) (r = 0.663, p = 0.001) in central subfield area was associated with best-corrected visual acuity (BCVA) gain, and had the best estimation of BCVA gain (adjust R2 = 0.544). Mean macular sensitivity in the central subfield was also well correlated with BCVA gain (r = 0.531, p = 0.016). CONCLUSIONS: Neural recovery occurred after the resolution of edema during conbercept treatment, due to the decreases in GCL and IPL associating with gains in vision and improved microperimetry.