Optic Nerve Head Parameters Research Articles

Three-dimensional mapping of peripapillary retinal layers using a spectral domain optical coherence tomography.

PurposeTo map and view the effects of age, gender, and axial length on seven individual retinal layers around the optic nerve head (ONH).MethodsWe scanned 242 healthy patients using the Spectralis spectral domain optical coherence tomography in an outpatient setting. The layers were observed on the Early Treatment Diabetic Retinopathy Study sectors using the standard Spectralis Family Acquisition Module 6.0.11.0. The center was the ONH, the inner circle (IC) was 1–3 mm away, and the outer circle (OC) was 3–6 mm away. The seven layers were 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). Additionally, we calculated the mean thickness of two combined layers: inner retinal layer (IRL) and photoreceptor layer (PL). Finally, we measured the mean of the total retinal thickness (TRT).ResultsThe TRT was highest at the inferior end in the IC and at the nasal end in the OC. The RPE (p<0.001) and PL (p<0.001) were thicker in males; however, the IRL (p=0.015) was thicker in females. We found that the RNFL (p<0.001, r=0.139), GCL (p<0.001, r=0.116), IPL (p=0.016, r=0.059), INL (p<0.001, r=0.104), OPL (p=0.009, r=0.064), ONL (p<0.001, r=0.157), RPE (p=0.001, r=0.079), IRL (p<0.001, r=0.190), PL (p=0.030, r=0.053), and TRT (p<0.001, r=0.191) correlated negatively with age. The axial length significantly and negatively correlated at the GCL (p=0.003, r=0.093), IPL (p=0.020, r=0.072), INL (p=0.018, r=0.073), ONL (p<0.001, r=0.110), IRL (p=0.003, r=0.092), and TRT (p=0.003, r=0.094). We found poor reproducibility in the IC; however, this was excellent in the OC.ConclusionWe found significant differences in layers according to age, gender, and axial length. Additionally, reproducibility can be improved by altering the algorithm to account for the ONH parameters.

Structural changes of the macula and optic nerve head in the remaining eyes after enucleation for retinoblastoma: an optical coherence tomography study

BackgroundTo describe objectively the possible structural changes of the macula and optic nerve head in the free eyes of unilateral cured retinoblastoma patients and, also after enucleation using spectral domain optical coherence tomography.MethodsA cross sectional study involving 60 patients subdivided into three groups; 15 unilateral RB patients in whom enucleation was indicated as a sole treatment performed earlier in life [(study group (I)], 15 unilateral RB patients who had completely regressed disease with a preserved eye [(study group (II)] and 30 age and sex matched healthy controls. The remaining and free eyes in study groups and right eyes of control group had full ophthalmological examination, static automated perimetry and optical coherence tomography of the macula and optic nerve head.ResultsIn study group (II); a significant thinning of total macula, central fovea, ganglion cell layer (GCL), ganglion cell complex (GCC), and some sectors of outer nuclear layer (P- values ≤0.05) was found with no significant difference in peripapillary nerve fiber layer (pRNFL) thickness and optic nerve head parameters compared to the control group and the study group (I). A significantly thickened total macula, GCL, GCC, and pRNFL in study group (I) compared to study group (II). Thickened pRNFL was significantly correlated to standard automated perimetry pattern deviations. No significant difference was found between study group (I) and control group.ConclusionRetinoblastoma eyes characterized by thinning of central fovea, GCL, GCC compared to the control group. After unilateral enucleation, increased GCC and pRNFL thicknesses were detected compared to retinoblastoma group.

The Future of Imaging in Detecting Glaucoma Progression

Ocular imaging has been heavily incorporated into glaucoma management and provides important information that aids in the detection of disease progression. Longitudinal studies have shown that the circumpapillary retinal nerve fiber layer is an important parameter for glaucoma progression detection, whereas other studies have demonstrated that macular parameters, such as the ganglion cell inner plexiform layer and optic nerve head parameters, also are useful for progression detection. The introduction of novel technologies with faster scan speeds, wider scanning fields, higher resolution, and improved tissue penetration has enabled the precise quantification of additional key ocular structures, such as the individual retinal layers, optic nerve head, choroid, and lamina cribrosa. Furthermore, extracting functional information from scans such as blood flow rate and oxygen consumption provides new perspectives on the disease and its progression. These novel methods promise improved detection of glaucoma progression and better insight into the mechanisms of progression that will lead to better targeted treatment options to prevent visual damage and blindness.

Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

BackgroundOptic nerve head (ONH) and surrounding structures such as β-zone peripapillary atrophy (PPA) are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.MethodsA total of 1,205 adult twins and their family members (362 monozygotic (MZ) twin subjects (181 pairs), 64 dizygotic (DZ) twin subjects (32 pairs), and 779 singletons from 261 families), were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.ResultsThe intraclass correlation coefficient (ICC) values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ConclusionsONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

Signal Alteration in the Optic Nerve Head on 3D T2-weighted MRI: a Potential Neuroimaging Sign of Glaucomatous Optic Neuropathy

ABSTRACTPurpose: To investigate whether a signal alteration (SA) in the optic nerve head (ONH) on 3D T2-weighted magnetic resonance imaging (MRI) is associated with glaucomatous optic neuropathyMaterials and Methods: A total of 35 patients with bilateral open-angle glaucoma and 31 age-matched controls underwent 3D high-resolution (0.98 × 0.98 × 1 mm3) T2-weighted MRI and detailed ophthalmologic examinations including spectral-domain optical coherence tomography (OCT). Two independent reviewers blinded to subject data determined mild or prominent SA on 3D T2-weighted MRI for the incomplete or complete loss of ocular hypointense continuity in the ONH, respectively. The prevalence of SAs was compared between the two groups with the chi-square test. The OCT measurements were compared among the eyes with a mild or prominent SA and those without an SA using the Kruskal–Wallis test.Results: Of the 35 eyes with glaucoma, 26 eyes (74.3%) exhibited an SA in the ONH, whereas it was observed in 5 (16.1%) of the 31 controls (P < 0.001). The eyes with a prominent SA had a significantly different average retinal nerve fiber layer thickness (P = 0.002) and the ONH parameters except for the disk area (all P < 0.001) than those without an SA. The eyes with a mild SA had a significantly narrower neural rim area, larger cup volume, and larger average and vertical cup-to-disk ratios compared with those without an SA (P = 0.011, 0.003, 0.004, and 0.004, respectively)Conclusions: The SA in the ONH on 3D T2-weighted MRI was significantly more frequent in eyes with open-angle glaucoma than in the controls.

Utility of Bruch membrane opening-based optic nerve head parameters in myopic subjects.

To evaluate whether the new rim analysis software with spectral-domain optical coherence tomography (SD-OCT) shows advantages over the retinal nerve fiber layer (RNFL) thickness in patients with moderate myopia. In this prospective cross-sectional study, we studied 65 healthy subjects, 37 with spherical refractive errors in the range of -3 to -6 D (moderate, G1) and 28 with less than -3 D (low/non-myopic, G0). All patients were examined with Heidelberg Spectralis SD-OCT, including Glaucoma Premium Module Edition (GPME) software. With GPME, we analyzed the neuroretinal rim (Bruch membrane opening-minimum rim width [BMO-MRW]) and RNFL. The average age of subjects was 30.2 ± 9.3 years for G0 and 29.9 ± 7.1 years for G1 (p = 0.903). Mean sphere was -0.5 ± 0.3 D (-1.25 to 0 D) G0 and -3.9 ± 0.3 D (-6.00 to -3 D) G1 (p<0.001). The RNFL thickness comparison between G0 and G1 showed a significantly lower thickness in G1 (p = 0.018). The BMO-MRW measurements were similar in both groups (p = 0.331). With the BMO-MRW examination, the number of sectors classified as pathologic per subject in G1 were significantly lower compared to RNFL analysis (p = 0.023). Ring analysis based on BMO-MRW measurements shows a lower rate of false-positives compared to RNFL thickness when studying healthy moderate myopic eyes and it would be advisable to take this into consideration when analyzing these patients.

ISNT rule applicability based on optical coherence tomography parameters in a normal Portuguese population

PurposeWe aim to determine the applicability of the inferior, superior, nasal and temporal neuroretinal rim (NRR) area characteristic configuration (ISNT rule) in adult normal Portuguese population based on spectral‐domain optical coherence tomographic (SD‐OCT) and assess demographic variations by age, sex, race and relation to optic disc area.MethodsProspective study with 188 eyes of 94 patients that underwent SD‐OCT with the new glaucoma module premium edition software (v.6.0). Patients with confirmed or suspected glaucoma, visual field defects, other optic disk or retinal abnormalities were excluded. Optic Nerve Head parameters such as Minimum Rim Width (MRW), Bruch's membrane opening (BMO) and thickness of peripapilar nerve fibre layer (RFNL) on four quadrants were analysed.ResultsThe mean age group was 55 years, 44% were men, 83% Caucasian and 17% melanodermic. Mean spherical equivalent was 0.10 (min −6.5, max +5), and mean best‐corrected visual acuity was 20/20 (min 20/40, max 20/16). NRR thickness area (MRW) was 376.0 μm ± 75.9, 345.4 μm ± 81.8, 365.1 μm ± 86.8, 240.5 μm ± 57.4, respectively on inferior, superior, nasal and temporal quadrants and ISNT rule was present in 23%. When excluding nasal quadrant (inferior &gt; superior &gt; temporal (IST) or inferior &gt; superior (IS)) such configuration was present in 71% and 73% of patients, respectively. Mean age and mean optic disk/scleral area was higher in those with ISNT rule present (58.8 vs 53.7 years and 2.08 mm² ± 0.4 vs 1.98 mm² ± 0.5, respectively) but was not significant (p &gt; 0.05) as were not sex and race differences.ConclusionsISNT rule in normal population is not confirmed by SD‐OCT assessed with ONH parameters and it is only present in 23% of eyes. The authors propose that a “IS/IST rule” seems more representative in a normal population as exclusion of nasal quadrant consideration increases prevalence.

Optic Nerve Head Parameters Measured with Spectral-Domain Optical Coherence Tomography in Healthy Turkish Children: Normal Values, Repeatability, and Interocular Symmetry

ABSTRACTTo determine normal values, repeatability, and interocular symmetry of optic nerve head measurements, three spectral-domain optical coherence tomography (SD-OCT) scans were obtained from 128 healthy Turkish children aged 5–17 years consecutively and prospectively. The mean disc area, rim area, cup volume, cup to disc area ratio, and vertical and horizontal cup to disc ratios were 2.30 ± 0.42 mm2, 1.84 ± 0.45 mm2, 0.09 ± 0.10 mm3, 0.20 ± 0.13, 0.37 ± 0.17, and 0.45 ± 0.20, respectively. The intraclass correlation coefficients were >0.9 for repeatability and >0.75 for interocular correlation. Interocular differences were not statistically significant (p > 0.05). Normal paediatric SD-OCT measurements of the optic nerve head are presented, which showed excellent repeatability and no interocular difference.

In vivo analysis of glaucoma-related features within the optic nerve head using enhanced depth imaging optical coherence tomography.

Structural differences between optic nerve head (ONH) parameters in glaucomatous and non-glaucomatous eyes has been documented, however the association between such parameters in patients with different disease stages is yet to be elucidated. We investigated the relationship between different laminar and prelaminar ONH structures using enhanced depth imaging spectral-domain optical coherence tomography (EDI OCT) in a population with and without glaucoma. In this observational case-control study, we prospectively enrolled healthy individuals and glaucomatous patients with different disease stages. All participants underwent EDI OCT imaging (Heidelberg Engineering). Following ONH parameters were measured on serial vertical B-scans by two examiners masked to patient’s clinical data: lamina cribrosa (LC) and prelaminar neural tissue (PLNT) thicknesses, Bruch’s membrane opening (BMO) and cup depth. Associations between cup depth, and laminar and prelaminar parameters were evaluated controlling for possible confounding factors such as axial length and disc size. Sixty-four eyes of 64 patients were included (30 with glaucoma and 34 controls). Eyes with glaucoma had significantly lower mean LC and PLNT thickness, and greater mean cup depth than controls (p<0.01). There was a significant negative association between PLNT thickness and cup depth in glaucomatous eyes (R2 = 0.158, p = 0.029). In addition, LC thickness correlated significantly with cup depth (R2 = 0.135, p = 0.045). Eyes with thinner LCs presented deeper cups. Overall, cup depth and BMO had the best and LC thickness had the worst intraobserver and interobserver reproducibility grading. In conclusion, significant associations were seen between cup depth, LC and PLNT thickness. Eyes with deeper cups not only had less neural tissue, but also thinner LCs, independent of disc size and axial length. Best reproducibility was found for prelaminar parameters compared to deeper ONH structures.

Intereye asymmetry of optic nerve head parameters and retinal nerve fibre layer thickness in patients with open angle glaucoma detected by spectral domain optical coherence tomography

INTRODUCTION. The aim of the study is to evaluate intereye asymmetry of optic nerve head (ONH) parameters and the circumpapillary retinal nerve fibre layer (cpRNFL) thickness in patients with primary open angle glaucoma (POAG). MATERIA LS AND METHODS. The study included 44 patients with POAG in both eyes, 48 binocular glaucoma suspects, and 75 individuals with two healthy eyes. A mixed group of 20 patients had only one eye that met the criteria for POAG. We evaluated the differences between right and left eyes and absolute intereye asymmetry for the individual ONH parameters and cpRNFL thickness, measured by spectral domain optical coherence tomography (SdOCT). RESULTS. The comparison of average values of the ONH parameters between the right and left eyes in the group of healthy subjects showed no significant differences apart from the significantly higher rim volume (RV) in the right eye. In addition, the cpRNFL was an average of 4.23 μm thicker in the right eye than in the left eye in healthy subjects. The absolute difference of ONH parameters between the eyes of patients with POAG was higher than in healthy patients for most parameters, but statistical significance was only reached for cup volume (CV). The asymmetry of the cpRNFL thickness increased in patients with glaucoma compared with healthy subjects. The absolute asymmetry of the average cpRNFL thickness in all quadrants was 12.07 μm in patients with glaucoma versus 6.56 μm in healthy subjects (p < 0.05). In the group of glaucoma suspects, cpRNFL intereye asymmetry decreased in almost all parameters in comparison to healthy patients with statistical significance for superior and inferior quadrant. CONCLUSIONS. In patients with POAG, the intereye asymmetry increases for ONH and cpRNFL parameters compared with healthy eyes; however, statistically significant differences were only found for the cup volume and cpRNFL thickness average for all quadrants. The onset of glaucoma is associated with a reduction of the physiologically occurring asymmetry that results from greater cpRNFL thickness in the right eye.

Evaluation of Optic Nerve Head Parameters and Retinal Nerve Fiber Layer Thickness in Axial Myopia Using SD OCT.

IntroductionThe purpose of this research was to study the effect of increased axial myopia, in non-glaucomatous eyes, and its correlation with ONH parameters, and RNFL thickness, using Cirrus HD 4000 SD-OCT.MethodsThe myopia group included 86 eyes of 86 patients, while the control group involved 92 eyes of 92 patients, attending the Ophthalmology Outpatient Clinic in Minia University Hospital, between November 2013 and March 2015. ONH parameters and peripapillary RNFL thickness measurement were evaluated by using SD-OCT, selecting the standard optic disc cube 200 × 200.ResultsThe mean age of the myopia group was (36.55 ± 9.44), the mean spherical equivalent was (−12.70 ± 3.87 D), and the mean axial length was (27.88 ± 1.92 mm). The control group had mean age of (34.82 ± 8.87), mean spherical equivalent of −0.65 ± 0.41 D, and mean AL of (22.16 ± 0.82). A significant difference was reported between the two groups, regarding disc area (p = 0.01), rim area (p = 0.001), vertical C/D (p = 0.01), average C/D ratio (p = 0.001), average and temporal RNFL thickness (p = 0.0001, p = 0.001, respectively).ConclusionA significant difference was found between highly myopic non-glaucomatous eyes and the control group, regarding ONH parameters and RNFL thickness as measured by SD-OCT. As OCT magnification adjusted ONH parameters were larger, global and the temporal RNEL were thicker in the myopia group, those magnification adjusted parameters helped in an accurate evaluation of ONH and RNFL in highly myopic eyes, in order to avoid misdiagnosis of glaucoma in such eyes.

Evaluation of retinal nerve fiber layer thickness and optic nerve head parameter in migraine as a risk factor in open angle glaucoma

Evaluation of retinal nerve fiber layer thickness and optic nerve head parameter in migraine as a risk factor in open angle glaucoma

The Characteristics of Deep Optic Nerve Head Morphology in Myopic Normal Tension Glaucoma.

To investigate the relationship between axial length (AL) and deep optic nerve head (ONH) structure and to evaluate the characteristics of deep ONH structures in myopic normal tension glaucoma (NTG). The following parameters were assessed using spectral-domain optical coherence tomography (SD-OCT): externally oblique border tissue (EOBT) length, ONH tilt angle, optic canal (OC) obliqueness, and β-zone peripapillary atrophy (PPA). In addition, the angular location of the maximal value of each parameter and retinal nerve fiber layer (RNFL) defect were measured using infrared and red-free photos. A total of 74 myopic NTG eyes and 67 myopic control eyes with a spherical equivalent < -0.5 diopters from 141 subjects were included. AL was correlated with the maximal values of EOBT length, ONH tilt angle, OC obliqueness, and β-zone PPA (P < 0.001, P = 0.003, P < 0.001, and P < 0.001, respectively). Multivariate logistic regression analysis revealed that temporally located maximal values of EOBT length, ONH tilt angle, and OC obliqueness were associated with the presence of myopic NTG (P = 0.014, P = 0.016, and P = 0.030, respectively). In myopic NTGs, RNFL defect locations were consistent with the locations of maximal values of EOBT length, ONH tilt angle, OC obliqueness, and β-zone PPA (P < 0.001, P < 0.001, P < 0.001, and P = 0.003, respectively). Temporalized angular locations of deep ONH parameters were associated with the presence of NTG in myopia. In myopic NTGs, the locations of deep ONH parameters were consistent with the locations of RNFL defect.

Optic Nerve Head in Central Retinal Vein Occlusion by Spectral-Domain OCT

To evaluate the morphology of optic nerve head by spectral-domain optical coherence tomography (SD-OCT) in patients with unilateral central retinal vein occlusion (CRVO). In 39 consecutive patients with unilateral CRVO and 39 healthy controls, morphologic parameters of optic nerve head were assessed in both eyes by Spectralis SD-OCT using a custom radial B-scan pattern. The length of Bruch membrane opening (BMO) was measured in OCT scans, and optic disc diameters (DD) were assessed in infrared fundus photographs. Axial length was determined by IOLMaster. The BMO length was measured in all eyes with CRVO, while DD was not assessed in 9 eyes (27.3%) that had undefined disc margins. Compared to healthy controls (mean BMO length 1,511 ± 79 μm, mean disc diameter 1,521 ± 77 μm), in eyes with CRVO with defined disc margins (n = 28 [71.8%]), no significant difference was found in BMO length and DD (1,473 ± 118 μm and 1,516 ± 104 μm, respectively). Eyes with CRVO with undefined disc margins had lower BMO length (1,289 ± 61 μm [-14.7%], p = 0.001); also, in fellow eyes, these patients had lower BMO length and DD. In all groups, no significant difference was seen between BMO and DD. A correlation was found between axial length and BMO length and disc diameter (both p<0.001). Most of the eyes with CRVO had normal optic disc diameter, but about 25% of patients with CRVO have reduced optic disc dimensions.

Interocular symmetry of retinal nerve fiber layer and optic nerve head parameters measured by Cirrus high-definition optical coherence tomography in a normal pediatric population.

Purpose:To determine interocular differences in the retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters in a pediatric population using Cirrus high-definition optical coherence tomography (HD-OCT).Methods:Seventy normal Indian children aged 5–17 years presenting to the Pediatric Clinic were included in this observational cross-sectional study. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the RNFL and ONH by Cirrus HD-OCT. Differences between the right and left eyes were calculated and values were compared by means of a paired t-test. Subjects were also divided into two groups based on age (under or over 10 years of age). Interocular differences in RNFL and ONH parameters together with sex and age variations for these differences were determined.Results:The mean age of studied pediatric population was 11.83 ± 3.3 years (range 5–17). Average RNFL thickness was 94.46 ± 8.7 μm (± SD) (range 77–111). Differences in the average RNFL between right and left eyes were not statistically significant (P = 0.060). Superior quadrant RNFL was thicker in the left eye and temporal quadrant was thicker in the right eye. Among ONH parameters, there were no statistically significant differences in any parameters, except vertical cup-disc (CD) ratio which was significant (P = 0.007). The 2.5%–97.5% limits of asymmetry were 9 μm for average RNFL, 0.14 for average CD ratio, and 0.22 for vertical CD ratio. Mean interocular RNFL thickness differences in superior, superior nasal, and temporal superior quadrants were 10.61 (P < 0.001), 12.57 (P < 0.001), and 4.46 (P = 0.002) μm, respectively. Interocular nerve fiber layer thickness differences were not significantly correlated with sex, while only significant differences with age were observed in 12 clock hour sector analysis, mainly in nasal inferior and inferior quadrant.Conclusions:We report the degree of interocular symmetry of RNFL and ONH parameters measured by Cirrus HD-OCT in a healthy pediatric population. The normal interocular RNFL asymmetry should not exceed 9 μm and vertical CD ratio beyond 0.22 should be considered for further investigations. The physiologic asymmetry provided by this study may assist in identifying changes in RNFL thickness and ONH parameters in pediatric glaucoma and ONH disorders.

Relationship between anterior segment and optic nerve head parameters in healthy subjects.

To determine the relationship between anterior segment and optic nerve head (ONH) parameters. Two hundred healthy subjects were enrolled in this study. The par-ticipants underwent measurement of anterior segment parameters with a Pentacam Scheimpflug system and imaging of the optic disc with confocal scanning laser ophthalmoscopy. Pearson's correlation coefficient was calculated to assess the associations between ONH and anterior segment parameters. Multivariate regression analyses controlling for age and disc area as confounding factors were also conducted. There were significant negative relationships between optic disc area and corneal thickness (p=0.03, r=-0.217) and volume (p=0.017, r=-0.239). Corneal refractive power was significantly correlated with cup area, rim area, rim volume, and cup/disc ratio (p<0.05 for all). An increase of 1 diopter in anterior corneal refractive power corresponded to a decrease of 0.022 in cup/disc ratio. Rim volume was negatively correlated with anterior chamber depth and anterior chamber volume (p<0.05 for both). A 1-mm3 increase in anterior chamber depth corresponded to a 0.154-mm3 decrease in rim volume. Mean and maximum cup depth measurements were not associated with any of the anterior segment parameters. In nonglaucomatous eyes, the dimensions and shape of the ONH may be related to anterior segment morphology. Therefore, it may be helpful to take anterior segment parameters into consideration in evaluating the OHN.

Optical coherence tomography (OCT) changes after achieving target intraocular pressure

Purpose The aim of this study was to evaluate the ability of optical coherence tomography (OCT) to detect the changes in retinal nerve fiber layer (RNFL) after reaching target intraocular pressure (IOP) in glaucomatous patients. Patients and methods Thirty-two (58 eyes) patients with a clinical diagnosis of primary open-angle glaucoma were assessed as regards peripapillary RNFL thickness and optic nerve head parameters by 3D-OCT for a follow-up period of 6 months. The drugs used to reach target IOP were Twinzol (dorzolamide 2%/timolol 0.5%) eye drops 5 ml and Ioprost (Latanoprost) 0.005% (50 mcg/ml) eye drops 3 ml. Eleven patients were treated with Twinzol only and reached target IOP after adding Ioprost. Eight patients were treated with Ioprost only and reached target IOP after adding Twinzol, and 13 patients had no added treatment, where four reached target IOP by Ioprost only, six reached target IOP by Twinzol only, and three reached target IOP by both drugs. OCT was done for all patients after achieving target IOP and was repeated after 6 months of medical control. Results The mean IOP before treatment was 29.89 mmHg and decreased significantly (P Conclusion Achieving target IOP in patients with glaucoma results in a significant change in the RNFL and ganglion cell complexes layer as shown by spectral-domain OCT.

Effect of phacoemulsification on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral-domain-optical coherence tomography.

PURPOSE:The purpose of this study is to determine the effect of phacoemulsification cataract extraction on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral domain optical coherence tomography.MATERIAL AND METHODS:A prospective, hospital-based study of 100 patients of 40 years of age and above, with no other ocular morbidity except cataract and planned for phacoemulsification with IOL implantation (SN60WF) at a tertiary centre at AIIMS, New Delhi, India. All patients underwent imaging with Cirrus SD-OCT model 400 and the optic disc cube 200x200 protocol at baseline and at 1 month follow up. Paired sample t-test was used to compare the RNFL parameters and ONH parameters.RESULTS:The mean age of subjects was 56.6 ± 12.3 years (70 males, 30 females). The average RNFL increased from 92.6 ± 5.4 μm to 101.3 ± 5.6 μm after phacoemulsification, an increase of 9% (P = 0.003) and the signal strength increased from 5.6 ± 0.5 to 7.6 ± 0.7, increasing by 35.7% (P = 0.004). There was a significant increase in the disc area (P = 0.004) and rim area (P = 0.004) but no significant change in vertical cup-disc ratio (P = 0.45) or average cup-disc ratio (P = 0.075). The quadrant-wise RNFL thickness increase in inferior, superior, nasal, and temporal quadrants was 12.6% (P = 0.001), 10% (P = 0.001), 5.6% (P = 0.001), and 3.2% (P = 0.001), respectively. The change in RNFL thickness was maximum in posterior subcapsular cataract (P = 0.001) followed by cortical (P = 0.001) and nuclear (P = 0.001) subtypes.CONCLUSIONS:A significant increase in RNFL thickness and signal strength was observed after cataract surgery using SD-OCT. The maximum change in RNFL thickness was in the inferior quadrant, where RNFL thinning is a significant predictor of glaucoma progression. The posterior subcapsular cataract interfered with RNFL measurement maximally due to its density and proximity to nodal point. After the cataract surgery, a new baseline needs to be established by obtaining fresh OCT images for assessing the longitudinal follow-up of a glaucoma patient.

Diagnostic ability of Humphrey perimetry, Octopus perimetry, and optical coherence tomography for glaucomatous optic neuropathy.

PurposeTo evaluate and compare the diagnostic accuracy of the Humphrey Field Analyzer (HFA), Octopus perimetry, and Cirrus OCT for glaucomatous optic neuropathy.MethodsEighty-eight healthy individuals and 150 open-angle glaucoma patients were consecutive and prospectively selected. Eligibility criteria for the glaucoma group were intraocular pressure ≥21 mm Hg and glaucomatous optic nerve head morphology. All subjects underwent a reliable standard automated perimetry with the HFA and Octopus perimeter, and were imaged with the Cirrus OCT. Receiver-operating characteristic (ROC) curves were plotted for the threshold values and main indices of the HFA and Octopus, the peripapillary retinal nerve fiber layer thicknesses, and the optic nerve head parameters. Sensitivities at 85 and 95% fixed-specificities were also calculated. The best areas under the ROC curves (AUCs) were compared using the DeLong method.ResultsIn the glaucoma group, mean deviation (MD) was -5.42±4.6 dB for HFA and 3.90±3.6 dB for Octopus. The MD of the HFA (0.966; P<0.001), mean sensitivity of the Octopus (0.941; P<0.001), and average cup-to-disc (C/D) ratio measured by the Cirrus OCT (0.958; P<0.001) had the largest AUCs for each test studied. There were no significant differences among them. Sensitivities at 95% fixed-specificity were 82% for pattern standard deviation of the HFA, 81.3% for average C/D ratio of OCT, and 80% for the MD of the Octopus.ConclusionsHFA, Octopus, and Cirrus OCT demonstrated similar diagnostic accuracies for glaucomatous optic neuropathy. Visual field and OCT provide supplementary information and thus these tests are not interchangeable.

Consistency of Bruch Membrane Opening Detection as Determined by Optical Coherence Tomography.

To investigate the consistency of Bruch membrane opening (BMO) detection as determined by Cirrus high-definition optical coherence tomography (OCT). This study enrolled 106 healthy eyes and 194 glaucomatous eyes who underwent OCT examinations. The location of BMO was evaluated by inspecting 72 cross-sectional optic nerve head (ONH) images (5 degrees intervals for 360 degrees) per eye in which BMO location is automatically detected by the OCT algorithm. The consistency of BMO detection was investigated by comparing consecutive cross-sectional ONH images. If the location of the BMO margin did not agree between images, it was considered as inconsistent BMO detection. Among 300 eyes, 21 (7.0%) showed inconsistent BMO detection. Inconsistency in BMO detection was associated with a higher degree of myopia (P<0.001). All inconsistent BMO detection was found in areas with β-zone peripapillary atrophy. Eyes with inconsistent BMO detection showed greater changes in ONH parameters and retinal nerve fiber layer thickness than eyes with consistent BMO detection (P<0.001). Although BMO locations were consistent in most cases, in some cases, there were inconsistencies in BMO locations determined by OCT, especially in myopic eyes with peripapillary atrophy. Inconsistency in BMO detection resulted in changes in ONH parameters and retinal nerve fiber layer thickness. These finding should be considered when assessing glaucoma by using OCT.