Optic Disc Evaluation Research Articles

Evaluation of the Different Methods of Optic Disc Examination in Glaucomatous Patients

Abstract Background Glaucoma is the second leading cause of irreversible blindness worldwide. It affects the nerve fiber layer which forms the optic nerve. Many patients discover glaucoma accidently when they’re doing regular checkups. Glaucoma may have no specific symptoms until the advanced stages and it can be diagnosed by measuring intra ocular pressure, optic disc evaluation and visual field examination. The present work aims at evaluation of different methods in optic disc examination in glaucoma patients to detect their efficacy in diagnosis and follow up. Purpose To evaluate the agreement among slit lamp biomicroscopy, stereoscopic fundus photography and OCT in glaucomatous patients regarding Disc area, Cup area and vertical cup disc ratio (VCDR). Material and Methods 14 known glaucomatous patients were included in this cross-sectional observational descriptive. All patients under went slit lamp biomicroscopy examination by using +90 lens, stereoscopic fundus photography to obtain 3D image for optic disc and using computerized program to measure the optic disc parameters and Optical Coherence Tomography for the optic disc. Results Comparing each examiner values measured on stereoscopic fundus image in comparison with OCT. Examiner one have a moderate reliability regarding disc area, cup area and VCDR with ICC 0.67, 0.67 and 0.50 and P values 0.68, 0.61 and 0.01 respectively and examiner two have a moderate reliability regarding disc area, cup area and VCDR with ICC 0.66, 0.63 and 0.54 and P values 0.16, 0.69 and 0.03 respectively and examiner 3 has a moderate reliability regarding disc area and VCDR with ICC 0.65, 0.71 and P value 0.69, 0.07 respectively while a good reliability for cup area with ICC 0.82 and P value 0.02. Comparing values obtained by slit lamp using +90 lens and stereoscopic fundus photography regarding VCDR there is a moderate reliability with ICC 0.50 and P value 0.06 for examiner one only. Conclusion The results of the present study showed that there is an moderate agreement between stereoscopic fundus photography and OCT and slit lamp values regarding disc area, cup area and CD ratio.

Evaluation of the different methods of optic disc examination in glaucomatous patients

Background Glaucoma is a leading cause of blindness worldwide. Many patients discover glaucoma accidentally during regular checkups. Purpose To evaluate the agreement using slit lamp biomicroscopy, stereoscopic fundus photography, and optical coherence tomography (OCT) in the evaluation of the optic disc area, the cup area, and the vertical cup disc ratio (VCDR) in glaucomatous patients. Patients and methods This cross-sectional observational study includes 28 eyes of glaucomatous patients. All patients underwent slit lamp biomicroscopy using a +90 D lens, stereoscopic fundus photography using a computerized program to measure the optic disc parameters, and OCT for optic disc evaluation. Three examiners did the analysis. Results Comparing results obtained on stereoscopic fundus photography and OCT, examiner one reported moderate reliability regarding disc area, cup area, and the VCDR with an intraclass coefficient (ICC) of 0.67, 0.67, and 0.50 and P values of 0.68, 0.61, and 0.01, respectively. Examiner two reported moderate reliability regarding disc area, cup area, and VCDR with an ICC of 0.66, 0.63, and 0.54 and P values of 0.16, 0.69, and 0.03, respectively. Examiner three reported moderate reliability regarding disc area and VCDR with an ICC of 0.65, 0.71, and P values of 0.69 and 0.07, respectively. A good reliability for the cup area was reported with an ICC of 0.82 and a P value of 0.02. The slit lamp and stereoscopic fundus photos showed moderate reliability compared with fundus photography values. Conclusion There is an agreement between values obtained by slit lamp biomicroscopy, stereoscopic fundus photography, and OCT.

Prevalence and clinical profile of glaucoma in rural-based tertiary care hospital

Abstract Context: Glaucoma is the second leading cause of world blindness. Considering the scarcity of glaucoma studies in the Western part of Maharashtra, we conducted this study to determine the prevalence of glaucoma among adults aged 18 years and above. Aims: To determine the prevalence and clinical profile of glaucoma in rural-based Tertiary Care Hospital. Settings and Design: A cross-sectional study carried out in an Ophthalmology outpatient department in a rural-based Tertiary care hospital. Materials and Methods: Five hundred and eighty-three patients underwent ocular examination including visual acuity, slit-lamp examination, optic disc evaluation with +78D lens and intraocular pressure measurement with Goldmann applanation tonometer, gonioscopy, visual fields examination by Humphrey Field Analyzer and optic nerve head analysis using optical coherence tomography scan of all the glaucoma suspects. Statistical Analysis Used: The data of patients were tabulated and analyzed using SPSS. Results: Out of 583 cases, 42 cases had primary glaucoma; thus, the overall prevalence of glaucoma was found to be 7.2%. The open-angle group had 38 (90.4%) cases, whereas the narrow-angle group had 4 (9.52%) cases. Out of the total of 113 hypertensive patients, 16 were found to have glaucoma (38.09%, P < 0.01), and out of 84 diabetic patients, 14 cases were glaucomatous (33.33%, P < 0.01). The prevalence of glaucoma was found to be significantly associated with a positive family history, as 6 cases (14.3%) out of 42 had a positive family history (P < 0.01). Conclusions: The prevalence of glaucoma was found to be high in the population of the rural Western part of Maharashtra. Screening for glaucoma among middle-aged people with a positive family history, hypertension, and diabetes would help us in the early diagnosis and management of this irreversible disease.

Prospective evaluation of ethambutol toxic optic neuropathy in patients of pulmonary tuberculosis

AimThe aim of the study was to evaluate visual parameters for early detection of ethambutol toxicity to prevent irreversible optic nerve damage. MethodThis cohort study included 50 newly diagnosed cases of pulmonary tuberculosis, i.e. 100 eyes, in people aged 18–72 years, who received ethambutol as part of the antitubercular therapy. Before starting antitubercular treatment, at each monthly visit, ophthalmic examination was done that included best corrected visual acuity, optic disc evaluation, colour vision, contrast sensitivity, pupil cycle time and automated perimetry for a period of six months. Ethambutol was discontinued in patients who showed signs of visual impairment. These patients were observed for another three months for reversibility of toxicity. ResultsVisual functions were normal in all patients at baseline. Out of 50 patients, 47 didn't show any signs of deterioration in visual functions even after six months of oral administration of ethambutol. However, 3 out of 50 patients, i.e. 6 eyes (6 %), showed signs of toxicity after 4–5 months – LogMAR visual acuity deteriorated from 0.00 to 1.08 (±0.40); mean contrast sensitivity deteriorated from 1.725 (±0.075) to 1.12 (±0.18); mean deviation in visual fields got impaired from −1.37 (±0.15) to −10.93 (±2.66); and colour vision got severely affected. All the affected patients were aged above 65. ConclusionIn the present study, six percent of 50 patients showed ethambutol toxic optic neuropathy. It was concluded that patients should be comprehensively evaluated for visual parameters before starting the ethambutol treatment. They should be closely monitored by an ophthalmologist for visual functions every month to detect ethambutol toxicity at the early reversible stage to prevent irreversible damage to the optic nerve. Patients should be asked to report immediately if they detect any blurring of vision or colour vision abnormality.

Optical coherence tomography angiography evaluation of optic disc and retinal vascular densities in obese patients

BackgroundTo evaluate optic disc and retinal vascular densities in obese patients using optical coherence tomography angiography (OCTA). MethodsThis study included 27 eyes from 27 obese patients with a body mass index (BMI) of ≥35 who were scheduled for bariatric surgery at the general surgery clinic and 26 eyes from 26 healthy individuals with a BMI of 18.5–24.9 kg/m2 who were of similar age and gender to the obese group. The macular vascular densities of the superficial and deep capillary plexuses (SCP and DCP, respectively), choriocapillaris flow area, optic disc peripapillary vascular density, and retinal thicknesses were evaluated using the OCTA device in obese patients and controls. ResultsThe mean age of the obese patients was 35.89 ± 10.93 years, and that of the controls was 32.31 ± 7.88 years (p = 0.199). The mean BMI values of the obese and control groups were 45.04 ± 6.89 kg/m2 and 23.19 ± 1.66 kg/m2, respectively (p < 0.0001). The whole, parafoveal, and perifoveal vascular density values of the SCP and those of the DCP were statistically significantly lower in the obese group than in the control group (p = 0.004, p = 0.011, p = 0.006, p = 0.036, p = 0.029, and p = 0.024, respectively). There was no significant difference between the two groups in terms of optic disc vascular density. Full retinal perifoveal thickness, full retinal perifoveal volume, inner retinal perifoveal thickness, and inner retinal perifoveal volume were statistically significantly lower in obese patients compared to the controls (p = 0.043, p = 0.042, p = 0.027, and p = 0.024, respectively). In addition, statistically significant negative correlations were found between BMI and the whole, parafoveal, and perifoveal vascular densities of the SCP and DCP and the whole vascular density values of the optic disc for all vessels and small vessels ​​(p = 0.017, r = -0.327; p = 0.043, r = -0.280; p = 0.033, r = -0.293; p = 0.034, r = -0.291; p = 0.017, r = -0.327; p = 0.023, r = -0.311; p = 0.031, r = -0.296; and p = 0.047, r = -0.274, respectively). ConclusionWe consider that the decrease in retinal vascular density and retinal thickness in obese patients is responsible for obesity-induced oxidative stress, increased inflammatory cytokines, and microvascular damage.

Evaluation of Macula and Optic Disc of Adult Amblyopia Patients with Diverse Etiologies using Optical Coherence Tomography Angiography

PURPOSE: To compare macula and optic-disc optical coherence tomography angiography (OCTA) metrics of adult amblyopic eyes with healthy controls and investigate whether these differ according to amblyopia etiology. METHODS: This cross-sectional study included 35 unilateral amblyopic adults (n = 35 eyes) and 35 age-matched healthy controls (n = 35 eyes). Amblyopia subgroups consisted of anisometropic (n = 12 eyes), strabismic (n = 12 eyes), and combined-mechanism amblyopia (n = 11 eyes). Foveal avascular zone area (FAZA), vessel density (VD), and retinal thickness were obtained using OCTA. Retinal thicknesses were measured at the fovea, parafovea, perifovea, and retinal nerve fiber layer. Foveal, parafoveal, perifoveal, whole-macula, intradisc, peripapillary, and whole-disc VD were recorded. Groups were compared regarding OCTA metrics after adjusting for axial length, spherical equivalent, age, gender, and signal quality index using a one-way analysis of covariance test. RESULTS: Amblyopic eyes had significantly lower foveal, parafoveal, perifoveal, whole-macula VD in superficial capillary plexus (SCP), and deep capillary plexus (DCP) than control eyes after adjusting for confounders (P &lt; 0.05 for all). All amblyopia subgroups had significantly lower parafoveal, perifoveal, and whole-macula VD in SCP and DCP than control eyes after adjusting for confounders (P &lt; 0.05 for all). There was no significant difference in retinal thickness, FAZA, intradisc VD, peripapillary VD, and whole-disc VD between amblyopic and control eyes, as well as amblyopia subgroups and control eyes. CONCLUSION: These results suggest that effect of amblyopia on macular microvasculature should be considered when interpreting OCTA metrics of adults with concomitant diseases. It also supports that adult amblyopic eyes of different etiology have similar microvascular features.

Evaluation of Optic Disc, Retinal Vascular Structures, and Acircularity Index in Patients with Idiopathic Macular Telangiectasia Type 2.

We aimed to compare the retinal, optic disc vascular density (ODVD) values, and acircularity index (AI) of patients with idiopathic macular telangiectasia type 2 (IMT) and healthy individuals using the optical coherence tomography angiography (OCTA) device. The study included 39 patients with IMT and 37 healthy controls. The OCTA findings of the patients and controls were examined. The total, parafoveal and perifoveal vascular density of the superficial capillary plexus, choriocapillaris blood flow, inside-disc ODVD, retinal nerve fiber layer (RNFL), and retinal thicknesses were found to be statistically significantly lower, and the foveal avascular zone value was statistically significantly higher in the IMT group compared to the control group (p = 0.001, p = 0.01, p = 0.02, p = 0.01, p = 0.009, p = 0.002, p = 0.02, respectively). There was a statistically significant negative correlation between best-corrected visual acuity (BCVA) and AI (p = 0.02), and a statistically significant positive correlation between peripapillary vascular density and BCVA (p = 0.04). We consider that the lower retinal, choriocapillaris, ODVD values, and retinal and RNFL thicknesses in the patients with IMT compared to the controls were due to vascular damage, remodeling, fibrosis, proliferation, and Müller cell damage. Ellipsoid zone defect, AI, and peripapillary vascular density are important indicators in the evaluation of visual acuity in these patients.

Comparison between Surgical Techniques Used for Revision of the Filter Bleb: A Randomized Controlled Clinical Trial

Introduction/Purpose: The aim of this study was to compare two surgical revision techniques in failed trabeculectomies after 6 months. Methods: Patients diagnosed with open-angle glaucoma who underwent trabeculectomy in at least one eye with uncontrolled intraocular pressure (IOP) after trabeculectomy performed at least 6 months before were enrolled in this prospective trial. All participants underwent a complete ophthalmological examination at baseline. Randomization was performed to one eye per patient to double-masked trabeculectomy revision or needling. Patients were examined on the first day, 7 days, 14 days, and then monthly until completing 1 year after surgical intervention. All follow-up visits included the following: patients reported ocular and systemic events, best-corrected visual acuity, IOP, slit-lamp examination, and optic disc evaluation for cup-to-disc ratio. Gonioscopy and stereoscopic optic disc photographs were taken at baseline and 12 months. After 1-year, the IOP and number of medications were compared between the groups. Absolute success criteria in the study were IOP <16 mm Hg, for 2 consecutive measurements without using a hypotensive medication. Results: Forty patients were included in this study. Among them, 38 completed 1-year follow-up (18 in revision group and 20 in needling group). The age ranged from 21 to 86 years, with a mean of 66.82 ± 13.44. At baseline, the average IOP was 21.64 ± 5.12 mm Hg (range from 14 to 38 mm Hg) in the entire group. All patients were using at least two classes of hypotensive eye drops, and 3 patients were using oral acetazolamide. The mean use of hypotensive eye drop medications was 3.11 ± 0.67 at the baseline for the entire group. In the present study, 58% of the patients presented complete success, 18% qualified success, and 24% failed in both groups. After 1-year treatment, both techniques were similar for IOP parameters and also for number of medications (p = 0.834 and p = 0.433, respectively). Regarding intra- or postoperative complications, one patient in each group needed a new surgical intervention, one in the needling group due to shallow anterior chamber and one in the revision group due to spontaneous Seidel sign, and one patient in the needling group underwent posterior revision due to fail. Conclusions: Both techniques were safe and effective for IOP control after 1 year of follow-up in patients who underwent to trabeculectomy more than 6 months before.

Stereoscopic vs. monoscopic photographs on optic disc evaluation and glaucoma diagnosis among general ophthalmologists: A cloud-based real-world multicenter study.

PurposeTo investigate whether stereoscopic vs. monoscopic viewing condition influences the evaluation of optic disc photographs for morphologic features and glaucoma likelihood in a general ophthalmologist population from multicenters on a cloud-based platform.MethodsA cross-sectional study of 519 pairs of stereoscopic and monoscopic photographs of optic discs with adequate quality were selected and presented using a cloud-based platform. A total of 21 general ophthalmologists from 14 centers assessed 15 morphologic features based on 5R's rules and estimated glaucoma likelihood for each assigned photograph. There were 93 pairs of stereoscopic and monoscopic photographs evaluated by a panel of glaucoma specialists and set as ground truth. The main outcome measures were the agreement between estimates and ground truth and the inter-grader agreements.ResultsThere were good agreements between ground truth and both monoscopic and stereoscopic estimates (stereo κ 0.532 and mono κ 0.494). There was also a substantial intra-grader agreement between monoscopic and stereoscopic evaluation of glaucoma likelihood (κ 0.636). In eyes with probable glaucoma, the accuracy of the stereo method was greater than that of the mono method (stereo 0.238 vs. mono 0.118) When compared with ground truth, stereoscopic photographs had a better agreement for disc size (stereo κ 0.447 vs. mono κ 0.183), disc color (stereo κ 0.612 vs. mono κ 0.549), neuroretinal rim shape (stereo κ 0.356 vs. mono κ 0.274) on the whole. The stereoscopic method also had a better inter-grade agreement for disc size, disc color, neuroretinal rim shape, and glaucoma likelihood (stereo κ 0.402 vs. mono κ 0.359) on the whole.ConclusionsIn the evaluation of optic disc photographs for morphologic features and glaucoma likelihood, the stereoscopic method showed superiority compared to the monoscopic method for general ophthalmologists. The stereoscopic method is more likely to identify glaucomatous eyes which need medical intervention.

Use of the ISNT rule for optic disc evaluation in 40 to 79 year old patients seen in optometric practice

The purpose this study was to investigate the association between intraocular pressure (IOP) and the outcome of ISNT rule assessment of the optic disc in healthy patients seen in mainstream optometric practice. Consecutive patients over the age of 40 years and with no known general- or ocular pathology were enrolled from 4 optometric practices in Norway and Sweden during a period of 9 months. The sample was stratified by age group (40-49, 50-59, 60-69 and 70-79 years) and ISNT rule outcome (obeyed or broken). Subjects underwent a full optometric examination including stereoscopic assessment of the optic disc with the use of the ISNT rule, followed by measurements of intraocular pressure (IOP), central corneal thickness (CCT) and vertical size of the optic disc. Odds ratio (OR) was used to assess the association between IOP and the outcome measure. Stratified and multivariable analyses were employed to investigate the effect of age, gender, CCT, refractive error and disc size on the association. IOP was dichotomized at a cut-off corresponding to the 75th percentile (18 mmHg), whereas numeric covariables were categorized at cut-offs corresponding to the 33rd (ONH 1.6 mm, CCT 545 μm) and 66th percentile (ONH 1.8 mm, CCT 571 μm), respectively. A total of 177 patients (F: 57%, age range 40-79 years) were included. IOP was significantly higher in patients with broken ISNT rule (16.6 vs. 15.5 mmHg, p = 0.046), corresponding to a crude OR of 2.0 (CI 0.95-4.24). In stratified and multivariable analyses the association between IOP and outcome of the ISNT rule was strengthened in males (OR 4.8) and in subjects with small discs (OR 2.2), however only the effect modification by gender reached significance. Further research is necessary to understand the possible implications of these findings on the assessment of optic discs with the use of the ISNT rule.

Prevalence and Associated Risk Factors of Primary Open Angle Glaucoma Among Patients With Type 2 Diabetes Mellitus: A Cross-Sectional Study From North India.

BackgroundGlaucoma is a category of disorders that cause visual loss due to damage to the optic nerve. It is the primary cause of irreversible blindness around the globe. In diabetic individuals, intraocular pressure (IOP) was found to be higher than in non-diabetics, and this impact was linked to a rise in fasting blood glucose levels. In light of the foregoing findings, the current investigation was carried out with the goal of determining the prevalence and associated factors for primary open-angle glaucoma in people with diabetes in a tertiary care teaching hospital.MethodsThis cross-sectional study was carried out in a tertiary care teaching hospital. For a twelve-month period (2021-2022), adult patients (with type 2 diabetes and an age of 18 years or more) attending the ophthalmology out patient department (OPD) were included. Demographic information, socioeconomic data, and medical, familial, and ocular history were all gathered. All individuals with diabetes had an initial ophthalmological evaluation [including best corrected visual acuity (BCVA), slit-lamp biomicroscopy, assessment of peripheral anterior chamber depth (ACD), fundus examination, stereoscopic optic disc evaluation, and IOP measurement] by a senior ophthalmologist. Pearson's Chi-square test was used to compare variables on a nominal scale, whereas the t-test for independent samples was used to examine variables on a continuous scale.ResultsOur study enrolled a total of 1262 diabetic patients out of which 62.0% of subjects were male. Most of the enrolled subjects belonged to the 61-70 years of age group (35.8%). The eye examination of enrolled subjects showed that out of 1262 diabetic patients, 197 subjects (15.6%) were having primary open-angle glaucoma (POAG). The vision (in the better eye) was analyzed among three groups [no glaucoma or sight-threatening diabetic retinopathy (STDR); only glaucoma; and glaucoma plus STDR] and it was observed that no perception of light (PL) was noticed in 0.2% and 1.2% of subjects in the “no glaucoma or STDR” and “only glaucoma” groups respectively. In our study, the variables significantly associated with the increased prevalence of glaucoma among diabetic subjects included illiteracy, family history of type 2 diabetes mellitus (DM), being hypertensive, non-intake of anti-hypertensive medication, and >10 years duration of DM (p<0.05).ConclusionFrom our study, we came to the conclusion that there is clear-cut evidence of an increased incidence of POAG in diabetic patients, which was 15.6%. The study also showed a significant association between age, education, diet, hypertension, family history of diabetes and duration of diabetes, and; POAG. However, no significant association was found between gender and POAG.

Association of metformin use among diabetics and the incidence of primary open-angle glaucoma - The Chennai Eye Disease Incidence Study.

Purpose:Studies have reported the usage of metformin being associated with the reduced risk of progression of glaucoma. The current study aims to determine the association of metformin usage among subjects with diabetes mellitus and the six-year incidence of primary open-angle glaucoma (POAG).Methods:In this prospective cohort study, subjects who did not have glaucoma at the baseline and had a follow-up after a six-year interval were included. Details such as medical and drug history, applanation tonometry, gonioscopy, pachymetry, optic disc evaluation, and automated perimetry were collected. Incident POAG was defined as subjects who do not have glaucoma at baseline and developed glaucoma as classified International Society of Geographical and Epidemiological Ophthalmology Classification at the follow-up. The association between the subjects who were on metformin for treatment of diabetes mellitus and development of incident POAG was assessed.Results:Among the 4302 eligible participants, 128 (3%) had incident POAG. There were 905 (21.0%) subjects who had diabetes mellitus of which 142 (15.7%) were using metformin. Of the subjects with POAG, 92 (71.9%) were nondiabetics and 36 were diabetics (28.1%). Among the diabetics, the incidence of POAG among those on metformin was 5.6% (8 participants) and those not on metformin was 3.6% (28 participants). There was no difference in the incidence of POAG in subjects with diabetes mellitus, with and without metformin use (P = 0.25). Logistic regression showed no association of metformin use with the incidence of POAG (OR: 1.33, 95 CI: 0.58–3.04, P = 0.49) after adjusting for age, gender, and place of residence.Conclusion:The current study did not find any association between the effects of metformin on the incidence of POAG.

Case Report: The efficacy of early phacoemulsification in the intraocular pressure control in primary angle closure glaucoma associated with cataract in a young female

Glaucoma is a leading cause of irreversible blindness worldwide. Among different types of glaucoma, irreversible bilateral visual impairment is more common in primary angle closure glaucoma (PACG) patients. PACG and cataract often coexist and are both more prevalent among the elderly population, being rare in children and young adults. Here, we discuss the case of a 39-year-old Caucasian woman with unilateral PACG associated with cataract. The patient presented with a several-day history of left sided headache, decreased and blurred vision as well as pain and redness of the left eye (LE). She reported similar episodes in the previous year. Visual acuity (VA) of the LE was limited to counting fingers and intra-ocular pressure (IOP) of the LE was 42 mmHg. Anterior segment examination of the LE revealed: edematous cornea, a peripheral anterior chamber depth corresponding to Van Herick’s grade 0, mid-dilated pupil and lens opacities with visible glaukomflecken. Gonioscopic evaluation revealed iridotrabecular contact for 360º, no visible angle structures and a flat–mild convex iris contour. Spectral domain optical coherence tomography suggested only a thinning of neuro-retinal rim at the lower pole. Following treatment of the initial symptoms, phacoemulsification with intra-ocular lens implant was performed. IOP improved and no IOP-lowering medication was required. The patient was monitored for VA, IOP, field of vision changes, and optic disc evaluation every six months for 2 years and no glaucomatous change occurred. The patient also denied ocular symptoms during this period. This case supports the effectiveness of early phacoemulsification in the IOP control in patients with PACG.

Neural Network-Based Retinal Nerve Fiber Layer Profile Compensation for Glaucoma Diagnosis in Myopia: Model Development and Validation.

BackgroundDue to the axial elongation–associated changes in the optic nerve and retina in high myopia, traditional methods like optic disc evaluation and visual field are not able to correctly differentiate glaucomatous lesions. It has been clinically challenging to detect glaucoma in highly myopic eyes.ObjectiveThis study aimed to develop a neural network to adjust for the dependence of the peripapillary retinal nerve fiber layer (RNFL) thickness (RNFLT) profile on age, gender, and ocular biometric parameters and to evaluate the network’s performance for glaucoma diagnosis, especially in high myopia.MethodsRNFLT with 768 points on the circumferential 3.4-mm scan was measured using spectral-domain optical coherence tomography. A fully connected network and a radial basis function network were trained for vertical (scaling) and horizontal (shift) transformation of the RNFLT profile with adjustment for age, axial length (AL), disc-fovea angle, and distance in a test group of 2223 nonglaucomatous eyes. The performance of RNFLT compensation was evaluated in an independent group of 254 glaucoma patients and 254 nonglaucomatous participants.ResultsBy applying the RNFL compensation algorithm, the area under the receiver operating characteristic curve for detecting glaucoma increased from 0.70 to 0.84, from 0.75 to 0.89, from 0.77 to 0.89, and from 0.78 to 0.87 for eyes in the highest 10% percentile subgroup of the AL distribution (mean 26.0, SD 0.9 mm), highest 20% percentile subgroup of the AL distribution (mean 25.3, SD 1.0 mm), highest 30% percentile subgroup of the AL distribution (mean 24.9, SD 1.0 mm), and any AL (mean 23.5, SD 1.2 mm), respectively, in comparison with unadjusted RNFLT. The difference between uncompensated and compensated RNFLT values increased with longer axial length, with enlargement of 19.8%, 18.9%, 16.2%, and 11.3% in the highest 10% percentile subgroup, highest 20% percentile subgroup, highest 30% percentile subgroup, and all eyes, respectively.ConclusionsIn a population-based study sample, an algorithm-based adjustment for age, gender, and ocular biometric parameters improved the diagnostic precision of the RNFLT profile for glaucoma detection particularly in myopic and highly myopic eyes.

Prevalence of Primary Open-Angle Glaucoma in Patients with Obstructive Sleep Apnea Syndrome in Thailand

Objective: To determine the prevalence of primary open-angle glaucoma (POAG) among patients with obstructive sleep apnea syndrome and to identify factors associated with intraocular pressure (IOP). Materials and Methods: Eighty-eight patients with obstructive sleep apnea (OSA) and 88 control subjects were enrolled. All subjects underwent eye examination including visual acuity, IOP, gonioscopy, optic disc, and visual field evaluation within one week of enrollment. Results: Three of the 88 patients with OSA (3.4%) and only one (1.1%) in the matched group had POAG, indicating no statistically significant difference in both groups (p=0.621). All patients with OSA diagnosed with POAG had severe OSA. OSA did not significantly influence the risk factor of POAG (OR 3.07, 95% CI 0.31 to 30.11, p=0.312). However, the presence of mean oxygen saturation of less than 88% or oxygen desaturation index (ODI) greater than 30 events per hour correlated with an elevation of IOP (p=0.026, 0.010). Based on apnea-hypopnea index (AHI) and ODI, there was medium correlation with IOP (Pearson correlation 0.342, 95% CI 0.143 to 0.5147, p=0.0011 and Pearson correlation 0.317, 95% CI 0.116 to 0.494, p=0.0025). Conclusion: The prevalence of POAG was 3.4% in patients with OSA when compared with 1.1% in control group. There was positive correlation between AHI or ODI with the IOP. Moreover, the presence of mean oxygen saturation of less than 88% or ODI of more than 30 events per hour correlated with an elevated IOP. Keywords: Glaucoma, Obstructive sleep apnea, Prevalence, Primary open-angle glaucoma, Sleep apnea

Automated segmentation of optic disc and optic cup for glaucoma assessment using improved UNET++ architecture

Glaucoma is one of the leading cause of blindness for over 60 million people around the world. Since a cure for glaucoma doesn’t yet exist, early screening and diagnosis become critical for the prevention of the disease. Optic disc and optic cup evaluation are one of the preeminent steps for glaucoma diagnosis. A novel approach is developed in this paper for the identification of glaucoma using a segmentation based approach on the optic disc and optic cup. The Dhristi dataset was used to help improve performance on a small dataset. A custom UNET++ model is built for the segmentation task by tuning the hyper-parameters in addition to a custom loss function. The developed loss function helps tackle the class imbalance occurring due to small size of the optic nerve head. The proposed approach achieves 96% accuracy in classifying glaucomatous and non-glaucomatous images based on clinical feature identification. The improvised model is able to achieve state-of-art results for Intersection over Union (IOU) scores, 0.9477 for optic disc and 0.9321 for optic cup, along with providing an enhancement in reducing the training time. The model was tested on publicly available datasets RIM-ONE, DRIONS-DB and ORIGA and is able to achieve an accuracy of 91%, 92% and 90% respectively. The developed approach is validated by training it over RIM-ONE dataset independently, without changing any model parameters. The model provides significant improvement in segmentation of the optic disc and optic cup along with improvement in training time.

Fight the silent thief of sight: glaucoma incidence in citizens of Sassari

PurposeTo identify the silent thief of sight in asymptomatic citizens of Sassari and assess the importance of the screening in glaucoma.MethodsSeven ophthalmologists performed free specialist examinations and included 322 asymptomatic subjects from 40 to 80 years. All volunteers attended the screening with assessment of intraocular pressure (IOP, air‐puff tonometer TX‐f Canon) and optic disc evaluation by fundus biomicroscopy. Subjects with optic nerve cupping underwent retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness examination (i‐Vue OptoVue OCT).ResultsSubjects with a diagnosis of hypertension or treated for glaucoma were excluded. Of the total 322 volunteers included, 23.6% had glaucoma familiarity, 8.7% declared that the screening was the first ophthalmological visit and 55,28% stated that they had never been examined with tonometry before. IOP was &gt;21 mmHg in the 7% and optic disc showed abnormal cupping in 6.8% of the volunteers. The 2.48% of the subjects had both ocular hypertension (IOP&gt;21 mmHg) and papillary abnormalities, and 7.4% of the 27 OCT performed showed anomalies.ConclusionsGlaucoma is one of the leading causes of irreversible blindness, but early detection and treatment could prevent severe vision loss. For these reasons, glaucoma screenings are fundamental even though they could have limited diagnostic power. In fact, subjects with OCT anomalies were directed to further examinations. The results of this screening are quite impressive, most of all the 8% of patients declaring that they had never underwent an ophthalmological visit and the 55% of patient that undertake a tonometry for the first time. The discrepancy between these data stresses the importance of a regular ophthalmological examination that is still confused with the visual acuity assessment made by opticians. Only a complete ophthalmological visit can diagnose conditions affecting irreversibly the vision, such as the silent thief of sight.

Optical coherence tomography angiography characteristics of optic disc melanocytoma

BackgroundOptic disc melanocytoma (ODMC) was a benign pigmented intraocular tumor with the rare potential malignant transformation. This study was designed to evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in ODMC.MethodsEyes of healthy individuals in a control group and of patients with ODMC were imaged by OCTA systems operating at 840 nm wavelengths and examined. The main outcome measures were OCTA images, qualitative evaluation of optic disc and tumor vasculature, quantitative vascular density (VD) and perfusion density (PD).ResultsOne eye of ten normal volunteers and ten patients with ODMC were imaged. Eyes affected by ODMC as compared to the eyes of the control group (all P < 0.05). The healthy optic disc had radially-oriented vessels within the retina on OCTA. Optic disc melanocytoma was characterized by globular, demonstrated tortuous blood vessels, uneven thickness, and relatively disorganized intratumoral vasculature. The VD and PD within ODMC were significantly higher (12.360% ± 4.175, 0.316% ± 0.119%, P < 0.0001) than in normal optic discs (4.160% ± 2.290, 0.102% ± 0.0, 56%, P < 0.0001). No significant differences were established of the VD and PD in each single measurement zone (P > 0.05) between the ODMC and the control eyes. At 840 nm, OCTA could provide sufficient visualization of the tumor vasculature and better penetration through thicker tumors. The full thickness was visualized even in thicker tumors and highly pigmented lesions (> 2 mm). Interpretable OCTA images were obtained in 96% of the participants in whom imaging was attempted.ConclusionsOCTA may provide a noninvasive, safe, and efficient technique for evaluating a variety of neoplasms including the growth and vascularity in ODMC. OCTA could facilitate the evaluation of the vascular abnormalities of tumors and the effect of melanin on the penetration of the OCTA beam was not significant.

Optic disc edema in fibrous dysplasia/McCune-Albright syndrome: Prevalence, etiologies, and clinical implications.

Fibrous dysplasia (FD) is a rare disorder of expansile fibro-osseous lesions that may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Optic disc edema is a potentially serious ophthalmologic finding that has been rarely reported in patients with FD/MAS. The purpose of this study was to investigate the prevalence and potential clinical associations of optic disc edema in a large cohort. Clinical records were reviewed from subjects in an ongoing FD/MAS natural history study. Computed Tomography scans were evaluated for the presence of structural craniofacial abnormalities associated with optic disc edema, including Chiari I malformation and space-occupying lesions. Craniomorphometric analyses were performed to determine optic canal diameter and intracranial volume. Statistical analyses were performed to compare clinical and radiographic features between subjects with and without optic disc edema. Optic disc edema was diagnosed in 7/187 subjects, for a prevalence of 3.7%. All subjects with optic disc edema were diagnosed before age 18years and had mild, non-progressive disease. Radiographic structural abnormalities, including Chiari I malformation, aneurysmal bone cysts, and arachnoid cysts, were associated with higher odds of optic disc edema (odds ratio [OR] 24.3; 95% confidence interval [CI], 4.2 to 121.4; p<0.01) (OR 18.0; 95% CI, 3.4 to 108.2; p<0.01). Treatment with leuprolide, a gonadotropin releasing hormone analog, was also associated with optic disc edema (OR 26.0; 95% CI 3.3 to 177.5; p<0.05). There was no significant association of optic disc edema with other MAS endocrinopathies, medications, optic canal diameter, or intracranial volume. Optic disc edema is an uncommon but potentially serious complication of craniofacial FD, which may occur more frequently in pediatric patients and those with structural craniofacial abnormalities. The potential association of leuprolide therapy with optic disc edema in this population warrants further study.

Prevalence of glaucoma in the elderly population in Taiwan: The Shihpai Eye Study.

Background:This study aimed to evaluate the prevalence, characteristics, and the awareness status of glaucoma in an elderly Chinese population.Methods:A total of 460 individuals aged ≥72 years were enrolled in this cross-sectional community-based eye disease screening program. Glaucoma was diagnosed according to the diagnostic criteria proposed by the International Society of Geographical and Epidemiological Ophthalmology. Characteristics of subjects with primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) were described and compared between groups using Mann-Whitney U and Fisher’s exact tests.Results:Forty subjects were diagnosed with glaucoma, including 17 subjects with POAG, 22 with PACG, and one with secondary glaucoma. The estimated prevalence of glaucoma, POAG, and PACG was 8.7%, 3.7%, and 4.8%, respectively. In total, 71% of the subjects with PACG and 77% of POAG subjects presented with a normal intraocular pressure (IOP) of <19 mmHg. The demographic and ocular characteristics were similar between the two groups; however, subjects with POAG had a longer axial length and smaller vertical disc diameter than those with PACG. Further, 95% of the glaucoma subjects ever visited the eye clinic, but only 32.5% of them were aware of the disease.Conclusion:Glaucoma is prevalent in the elderly population in Taiwan, but the diagnostic rate and disease awareness are low. Since most subjects with glaucoma presented with normal IOPs, optic disc evaluation is critical for diagnosing glaucoma in the elderly in Taiwan