Optic disc

The congenital optic disc pit is a rare anomaly that can lead to major visual impairment associated with subretinal fluid accumulation. The authors describe the optical coherence tomography study of three cases of untreated congenital optic disc pits with different levels of visual impairment and its different presentations of intraretinal fluid collections.

correction. Pearson’s correlation coefficients were used to evaluate the associa- tions among various parameters of optic disc morphology as measured using the SD-OCT, HRT2, and fundus photographs. Univariate and multivariate logistic regression analyses were performed to determine the association between each optic disc parameter and the presence of LC defects. Optic disc parameters, including disc area, ovality index, optic disc cyclotorsion, PPA length with/ without BM, horizontal/vertical tilt angle, and transverse/longitudinal diameters, were the independent variables. The presence/absence of LC defects was used as the dependent variable. All statistical analyses were performed using SPSS software version 19.0 (SPSS, Chicago, IL). P values less than 0.05 were accepted as statistically significant, except for those calculated to compare PICCs.

Incidence of ODE as assessed by slit-lamp biomicroscopy was 0% at BL1 and reached 64% on day1 (evening) at the CM; incidence increased to 79% on day2 and decreased to 64% on day3 (no slit lamp biomicroscopy was performed on day4 due to organization of descent). At BL2 all discs had returned to normal and no ODE was observed. Data are given in Table 2. Optic discs judged as equivocal were not considered. Interestingly, optic disc margins were blurred most noticeably on the nasal side of the disc. Statistical analysis of quantitative stereometric parameters (HRT3H) confirmed the clinical impression of symmetric ODE changes with no statistically significant differences between the right and left eye for BL1, BL2 and any of the high altitude recordings of day1–4 (data not shown). Therefore, only measure- ments of right eyes are presented in the following. Quantitative measurements (HRT3H) before and after high altitude exposure (BL1 vs. BL2) did not reveal statistically significant differences (95% confidence interval (CI) ; p.0.50) for all 12 outcome measures (see methods section and Table S1), indicating complete reversibility of all changes that had developed during exposure to high altitude. Specifically, CI and p-values (BL1 vs. BL2) of all key stereometric parameters were: rim volume (CI for BL1 = 0.33 to 0.47 and BL2 = 0.33 to 0.46; p = 0.92), mean RNFL thickness (CI for BL1 = 0.24 to 0.30 and BL2 = 0.24 to 0.30; p = 0.90), RNFL cross sectional area (CI for BL1 = 1.13 to 1.45 and BL2 = 1.13 to 1.45; p = 0.99) and maximum contour elevation (CI for BL1 = 20.16 to 20.09 and BL2 = 20.17 to 20.11; p = 0.60). The complete data set is provided as Table S1. As illustrated in Figure 2, HRT3 H analysis using the automated track change analysis (TCA) showed an increase in neuroretinal rim height between BL1 and recording at high altitude (day2). However, six hrs after arrival at the CM on day1 the increase in RNFL thickness was not statistically significant, but reached significance in the morning at day2, 3 and 4 (Figure 3A). An identical pattern was seen for the ratios of rim volume, RNFL cross sectional area and maximum contour elevation, that were also significantly higher on day2, 3 and 4 than at BL1, but not on day1 (Figure 3B–D). Average variability, maximum and mean cup depth remained stable overall, but were significantly increased on day1 or on day2 respectively. Cup volume, cup and disk rim areas, and vertical cup/disk ratio remained unchanged at altitude. Data of all 12 stereometric parameters at high altitude from day1–4 compared to BL1 recordings are summarized in Table 3.

This study has limitations. First, empirically derived formulas were used to estimate the number of RGCs and the original formulas were derived from studies in a primate model of glaucoma and likely need refinement.[10] However, the formulas have been validated in multiple external human cohorts [11,12,17] and the RGC estimates obtained using these formulas are closely related to the findings of human histological studies. [10,40–42] Another potential limitation is that some patients in the no hemorrhage group may have experienced a disc hemorrhage that went undetected during follow up. This is a potential problem as disc hemorrhages may resolve fairly quickly. Kitazawa and colleagues reported that disc hemorrhages are typically present for 4 weeks to 2 months before they resorb and disappear. [43] It is important to note that even if some patients without observable disc hemorrhage may have had undetected bleeding during follow- up, this would actually tend to decrease the difference between the two groups. Therefore, our results may be seen as conservative estimates of the differences in rates of change between the two groups. Moreover, evaluation of stereophotographs is a good method for detection of disc hemorrhages. In the OHTS 84% of patients with disc hemorrhages were identified only in photo- graphs whereas only 16% were identified by both clinical examinations and photographs. [5] It should also be acknowl- edged that we did not examine the temporal relationship between the appearance of a disc hemorrhages and disease progression. Instead, rates of RGC loss were calculated for the entire follow up period and disc hemorrhages could have occurred at any time during follow up. This approach was used due to the relatively limited follow up time available with HDOCT measurements. Future studies should attempt to investigate the temporal relationship between optic disc hemorrhages, structural measure- ments and estimated rates of RGC loss in glaucoma.

The blood vessels enter the eye from a single point (optic disc) and tend to spread in an hyperbolic manner, in such a way that the fovea will be located in a area without any blood vessels. This behaviour displayed by the blood vessels can be used to determine the optic disc, as shown by Forracchia et al.[4], Tobin[8] and Sinthanayothin et al.[2]. All these works use the behaviour of the blood vessels as a way to detect the optic disc, but they use several steps with some computational load to achieve it. In RetScan a lightweight method to pinpoint the approximate location of the optic disc might be more appropriate, and to that affect, the vessel trace can be used.

The optic disc (OD) is one of the major landmarks that stand out from the observation of a human retina. OD localization is fre- quently required for the implementation of image analysis-based solutions for the assessment and follow-up of several eye condi- tions. Detection of the OD is relevant in glaucomatous eyes as this disorder affects the shape and appearance of the disc, but it can also be useful for differentiating from white lesions related to diabetic retinopathy, or from drusen associated with age-related macular degeneration [1]. Knowledge about OD position is also required for automating the determination of diagnostic indexes for hyperten- sive retinopathy, such as the Arteriolar-to-Venular diameter ratio (AVR) [2].

Abstract—An efficient detection of optic disc (OD) in colour retinal images is a significant task in an automated retinal image analysis system. Most of the algorithms developed for OD detection are especially applicable to normal and healthy retinal images. It is a challenging task to detect OD in all types of retinal images, that is, normal, healthy images as well as abnormal, that is, images affected due to disease. This paper presents an automated system to locate an OD and its centre in all types of retinal images. The ensemble of steps based on different criteria produces more accurate results. The proposed algorithm gives excellent results and avoids false OD detection. The technique is developed and tested on standard databases provided for researchers on internet, Diaretdb0 (130 images), Diaretdb1 (89 images), Drive (40 images) and local database (194 images). The local database images are collected from ophthalmic clinics. It is able to locate OD and its centre in 98.45% of all tested cases. The results achieved by different algorithms can be compared when algorithms are applied on same standard databases. This comparison is also discussed in this paper which shows that the proposed algorithm is more efficient.

A 69-years-old male patient was treated with amiodarone 200mg/day over the passed two months for atrial fibrillation. He presented a sudden, painless and unilateral visual loss. Ophthalmologic evaluation revealed a bilateral optic disc edema. Neurological examination was otherwise unremarkable. After properly excluding increased intracranial pressure and giant cell arteritis, the main differential diagnosis was between nonarteritic anterior ischemic optic neuropathy and optic neuropathy secondary to amiodarone. The latter diagnosis was favored due to a presence of bilateral and simultaneous optic disc edema, gradual improvement of symptoms after discontinuation of the drug, and, mostly, by persistence of optic disc edema beyond 6 weeks. Of note, an acute presentation of this disorder is common. Amiodarone optic neuropathy is a rare but potentially serious cause of optic nerve dysfunction, and its discontinuation is usually warrant.

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When a patient with glaucoma presents with visual field defects that do not match the optic disc changes and has other associated symptoms, such as the ones mentioned above, further neurological investigation is always warranted. Finally, early diagnosis and surgical intervention are critical for a good visual prognosis. Therefore, involvement of the ophthalmologist is essential for appropriate diagnostic investigation and clinical management of such neuro-ophthalmic conditions.

Objective evaluation of eye torsion was performed by retinogra- phy one week before and one month after the surgery. Mydriasis was achieved with instillation of one drop of tropicamide 1% in each eye. The head of the patient was stabilized in the chin and forehead rests and eye height was regulated according to the markings in the reti- nographer. The examiner took care to observe that the patient’s head was straight while being photographed; however, no special head brace or leveling device was used. The patient was asked to look at the internal target of the instrument. With the help of a circle-shaped device on the screen of the instrument, the examiner established the position of the optic disc and of the macula in relation to the posterior pole, placing the fovea at the center of the device. The image obtai- ned was used to measure the torsion angle with a software applied in architecture, Autocad 2009® (Autodesk, Inc. San Rafael, California). Four lines were drawn tangent to the upper, medial, lower and lateral extremities of the optic disc, forming a rectangle, and two diagonal lines crossing the internal angles of the figure. This was the manner to determine the center of the disc, through which a horizontal line was drawn parallel to the upper and lower horizontal lines of the rectan- gle (Figure 1 A). Then, another line was drawn connecting the center of the optic disc to the center of the fovea, and the angle formed by the two lines was measured, which was called the “torsion angle” (Figure 1 B). The normal location of the fovea was considered to be between the center of the optic disc and a 7.25° angle below the ho- rizontal line that crosses the center, according to the study performed by Bixenman and Von Noorden (2) . For the sake of convention, positive

in a patient with an inferior tilted disc and superior RNFL loss is most probably related to tilted disc morphology instead of glaucomatous optic neuropathy; however, this argument needs to be proven by large-scale studies comparing visual ields in both glaucoma and til- ted disc groups. In addition to clinical examination, realization of OCT in conjunction with perimetry can help in the diagnosis and monito- ring of glaucoma in cases of concomitant optic disc tilt. OCT appears to have the ability to distinguish normal from glaucomatous optic nerve heads, but it is not clear that these indings can be generalized to tilted disc and glaucoma (25) . Witmer et al. (2) partly supported this

In this study, we performed for the first time an optic nerve head morphometric analysis and a peripapillary RNFL examination in FAS patients, using SD-OCT. We also established a pattern of axonal loss. This finding may be useful to further determine the presence of FAS status. It is known that OCT, particularly spectral domain new generation, is a powerful and widespread tool in neurophthalmology practice. However, although OCT is actually being used in the assessment of the optic disc morphometry and RNFL and ganglion cell layer thicknesses in many diseases, to the best of our knowledge, there are no studies of its utility in FAS. Our study aimed to evaluate optic disc morphometry and RNFL thickness in a cohort of FAS patients and compare these structural data with a control age-matched group.

In the LE, detachment of the sensory retina was observed, affecting the macular region and reaching the temporal edge of the optic disc. The patient then underwent an OCT scan (Figures 1 and 2), which confirmed the temporal optic disc pit and the presence of a macular microhole in the RE. In the LE, the OCT clearly showed the optic disc pit with a communication between the subretinal space and the inferior temporal region of the optic disc, indicating a possible orifice communicating these structures. Furthermore, a loss of foveal contour was observed with serous detachment of the neurosensory retina, more pronounced in the region nasal to the fovea, and a content of average reflectivity was seen in the central macular region (Figure 1).

All of the patients underwent a complete ophthalmic examination including visual acuity (VA) assessment, refraction test, slit-lamp biomicroscopy, gonioscopy, Goldmann applanation tonometry, and dilated stereoscopic examination of the optic disc. They also underwent stereo disc photography, circumpapillary RNFL thickness measurement and EDI optic disc scanning using SD-OCT (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany), standard automated perimetry (Humphrey Field Analyzer II 750; 24–2 Swedish interactive threshold algorithm; Carl-Zeiss Meditec, Dublin, CA, USA), and measurements of corneal curvature (KR-1800, Topcon, Tokyo, Japan), central corneal thickness (Orbscan II, Bausch & Lomb Sur- gical, Rochester, NY, USA), and axial length (IOL Master version 5, Carl-Zeiss Meditec).

14. Insull E, Nicholas S, Ang GS, Poostchi A, Chan K, Wells A. Optic disc area and correla- tion with central corneal thickness, corneal hysteresis and ocular pulse amplitude in glaucoma patients and controls. Clin Experiment Ophthalmol. 2010;38(9):839-44. 15. Wu RY, Zheng YF, Wong TY, Cheung CY, Loon SC, Chauhan BC, et al. Relationship of

Using HRT technology in the present study, we found statistical improvement af- ter IOP reduction in optic disc parameters related only to cup volume in group A, which had relatively greater IOP reduction, and none in group B, which had less IOP reduc- tion. Other topographic parameters improved in group A, but did not reach statistical significance, probably because of lack of power to detect these differences. The sample size is to small to find significant differences for most of the HRT parameters and larger studies or meta-analyses are needed to clarify the real influence of the IOP on HRT param- eters. Nevertheless, the findings of some outliers with big differences in HRT param- eters after surgery should be a concern in clinical practice.

reported for the first time optic disc pigmentation associated with pigmentary mottling of the fundus in one patient with nevus of Ota. Thus, to the best of our knowledge, this is the second Brazilian report of this unusual optic disc pigmentation of nevus of Ota. A marked pigmentary mottling of the ocular fundus may have some significance. Malignant choroid melanoma is a potential ocular risk in oculodermal melanocytosis in Asian patients. (17,18) Increased numbers of

Herein, we report a case of nonarteritic anterior ischemic optic neuropathy (NAION) following uneventful pars plana vitrectomy for macular hole treatment. A 56-year-old previously healthy woman presented with a full-thickness macular hole in right eye (OD) and small cup-to-disc ratios in both eyes. Five days after surgery, she noticed sudden painless loss of vision in OD and was found to have an afferent pupillary defect and intraocular pressure of 29 mmHg. Fundus exami- nation showed right optic disc edema and the resolution of a macular hole with an inferior altitudinal visual field defect. Erythrocyte sedimentation rate, C-reactive protein levels, and general physical examination findings were normal. She was treated with hypotensive eyedrops and oral prednisone, resulting in mild visual improvement and a pale optic disc. A combination of face-down position and increased intraocular pressure due to a small optic disc cup were considered as potential mechanisms underlying NAION in the present case. Vitreoretinal surgeons should be aware of NAION as a potentially serious complication and be able to recognize associated risk factors and clinical findings.

A slit lamp examination of the anterior segment was within the normal range, with all media being transparent and intraocular pressure of 16 mmHg BE. Fundoscopy showed a blackened, rounded and elevated lesion on the papilla of the optic disc, affecting the lower nasal quadrant of the left eye. He had no previous diagnosis of lesions in the eye fundus.