Frequency doubling technology and scanning laser tomography in eyes with generalized enlargement of optic disc cupping

PURPOSE: To characterize functional and structural changes in eyes with generalized enlargement of optic disc cupping (vertical cup/disc ratio > or = 0.8), normal intraocular pressure, normal standard achromatic automated perimetry (SAP) results, and no other ophthalmoscopic findings suggesting glaucoma (large C/D eyes) using frequency doubling technology (FDT) and the Heidelberg Retina Tomograph (HRT). METHODS: This comparative observational case series included 30 large C/D eyes (30 subjects), 17 eyes (17 patients) with early-stage normal tension glaucoma with generalized enlargement of optic disc cupping (NTG eyes), and 25 eyes from 25 normal subjects (normal eyes). Results with Humphrey 30-2, FDT N-30 threshold programs, and HRT were compared among these groups. Large C/D eyes were subdivided into FDT-normal and -abnormal eyes according to the predetermined criteria and HRT parameters were compared among them. RESULTS: No significant difference was seen in HRT parameters between the large C/D and NTG eyes. In the large C/D eyes, FDT mean deviation was lower than in the normal eyes and higher than in the NTG eyes, whereas FDT pattern standard deviation was smaller than in the NTG eyes (P = 0.02-0.03). Among HRT parameters, only cup shape measure (CSM) showed significant negative correlation with FDT mean deviation in the large C/D eyes. Between FDT-normal and -abnormal subgroups, only CSM showed significant difference (P < 0.01). CONCLUSION: Frequency doubling technology showed abnormalities in large C/D eyes. Only CSM showed significant correlation with FDT result and difference between those with normal and abnormal FDT results. In management of large C/D eyes, FDT and CSM will be useful to detect functional and structural change.     

Characteristics of optic disc in healthy school children

The ophthalmoscopic features of the optic discs were studied in a series of 411 non-selected school children representing four age groups from 7 to 15 years. The distribution of the cup disc diameter ratios (C/D) showed that in the majority of the eyes (58.8%) the ratio was 0.2--0.3, independently of the age group. The highest ratio recorded, 0.7, was found in two eyes of the series. An asymmetry of 0.2 or more in the C/D ratios of the eyes was found in 5.2% of the children studied. The correlation between C/D ratio and the age or refraction was not statistically significant although C/D ratio of 0.4 or more was significantly commoner in myopia of -2.0 D. or more than in the other eyes. A preponderance of large C/D ratio was also found in children with a birth weight of 2500 g or less but the difference from the distribution in the total series was not significant. Cilioretinal arteries were detected in 17.7% of the eyes and in 27.3% of the subjects studied. In 8.1% of the children the condition was bilateral. In children with a birth weight of 2500 g or less cilioretinal arteries were found in more than half of the cases.     

Optic disc evaluation by optical coherence tomography in nonarteritic anterior ischemic optic neuropathy

PURPOSE: To describe the characteristics of the optic nerve head (ONH) in patients with nonarteritic anterior ischemic optic neuropathy (NAION) and compare them with control subjects by using optical coherence tomography (OCT). METHODS: Patients with NAION underwent a complete ophthalmic examination, including OCT scanning of the ONH at diagnosis. The examination was repeated 1.5, 3, and 6 months later. Age- and sex-matched control subjects with no ocular disease underwent a similar evaluation. Data were obtained by using the ONH analysis protocol of the StratusOCT (Carl Zeiss Meditec, Dublin, CA). RESULTS: Twenty-three patients and 23 control subjects were included. In eyes with NAION, the vertical integrated rim area decreased significantly (P < 0.01) from the acute phase to the 6-month visit. The cup-to-disc (C/D) area ratio increased significantly (P = 0.002) from the acute examination to the 3-month visit. There was a significant difference between the NAION fellow eyes and the control eyes in C/D ratio, evaluated by slit lamp funduscopy (P < 0.001), and in the C/D area ratio (P = 0.001). The vertical integrated rim area was significantly (P = 0.001) greater in NAION fellow eyes than in control eyes. There was no significant difference in optic disc area or vertical disc diameter among the control eyes, NAION-affected eyes, and NAION fellow eyes. CONCLUSIONS: Although patients with NAION have lower C/D ratios than does the normal population, with a higher level of nerve fiber crowding, there was no difference in optic disc size between patients with NAION and control subjects. After the development of NAION, 47.8% of eyes had a C/D ratio that differed from that in the fellow eye by more than 0.1.     

Usefulness of optical coherence tomography parameters of the optic disc and the retinal nerve fiber layer to differentiate glaucomatous, ocular hypertensive, and normal eyes

PURPOSE: To assess Stratus optical coherence tomography (OCT) original parameters for identifying glaucomatous damage and to evaluate differences among glaucomatous, ocular hypertensive, and normal eyes. DESIGN: Cross-sectional prospective study. SUBJECTS AND METHODS: The study was conducted at 2 centers. The study population consisted of 55 normal individuals, 95 patients with ocular hypertension (OHT), and 79 patients with glaucoma. Retinal nerve fiber layer (RNFL) and optic nerve head OCT protocols were used to evaluate all study participants. Measurements taken were RNFL thickness, several ratios, RNFL asymmetry between both eyes, rim volume, rim width, disc area, cup area, rim area, cup/disc (C/D) area ratio, and horizontal and vertical C/D ratios. The main outcome measures were the differences in OCT parameters among groups and the areas under the receiver operating characteristic curves (AROC). RESULTS: Mean RNFL thickness around the disc, and superior and inferior RNFL thickness, were significantly thinner in glaucomatous eyes than in OHT or normal eyes (P<0.001). Rim parameters were significantly smaller in glaucomatous eyes than in normal (P<0.001) and OHT eyes (P=0.01). C/D ratios were significantly greater in glaucomatous eyes than in OHT (P<0.001) and normal (P<0.001) eyes. Significant differences were found between normal and OHT eyes in 7 disc parameters. No difference was found among groups in parameters describing RNFL asymmetry between both eyes. The AROC curves of the other RNFL and disk parameters ranged from 0.741 to 0.85. CONCLUSIONS: Almost all RNFL and disc parameters showed significant differences and discriminated between glaucomatous and normal eyes. There were significant differences in some optic nerve parameters, but no RNFL parameters, between normal and OHT eyes.     

Optic nerve compression by normal carotid artery in patients with normal tension glaucoma

AIM: To determine whether compression of the optic nerve by the intracranial carotid artery (ICA) can be a causative factor of normal tension glaucoma (NTG). METHODS: The medical records of 103 eyes of 54 Japanese patients with NTG and 104 eyes of 52 age matched control patients were reviewed. The neuroradiological findings of magnetic resonance images (MRI) were evaluated to determine the relation between the optic nerve and ICA. The clinical characteristics and general medical conditions, such as diabetes and systemic hypertension, were also compared between the two groups. RESULTS: The prevalence of optic nerve compression by the ICA in patients with NTG was 49.5%, which was significantly higher than that in control group with 34.6% (p = 0.035). Bilateral compression of the optic nerve was detected in 22 patients with NTG (40.7%), and this was also significantly higher (p = 0.029) than that in the control group (11 patients, 21.2%). In the NTG group, eyes with cup/disc ratio (C/D ratio) > or =0.7 showed a higher percentage of compression (52.6%) compared with eyes with C/D ratio of <0.7 (12.5%; p = 0. 042). The presence of diabetes and hypertension did not affect the incidence of optic nerve compression by ICA significantly. CONCLUSIONS: The significantly higher percentage of NTG patients who had optic nerve compression by the ICA suggests that compression of the optic nerve by ICA may be a possible causative factor or a risk factor for optic nerve damage in some patients with NTG.     

Posterior segment manifestations of Rickettsia conorii infection

PURPOSE: To characterize and analyze the posterior segment manifestations of Mediterranean spotted fever (MSF), an infectious disease caused by Rickettsia conorii. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: Thirty patients (60 eyes) with serologically proven MSF at the acute stage. METHODS: Patients underwent complete ophthalmic examination, including dilated biomicroscopic fundus examination, fundus photography, and fluorescein angiography. Sequential follow-up examinations were performed in patients with evidence of posterior segment involvement. RESULTS: Of 30 patients, 25 (83.3%) had unilateral (n = 5) or bilateral (n = 20) posterior segment involvement related to MSF. Of those 25 patients, 16 (64%) had no ocular symptoms, and 9 (36%) had ocular complaints. Findings included mild vitreous inflammation (45 eyes [75%]), white retinal lesions (18 eyes [30%]), focal vascular sheathing (5 eyes [8.3%]), multiple arterial plaques (1 eye [1.7%]), intraretinal hemorrhages (14 eyes [23.3%]), white-centered retinal hemorrhages (2 eyes [3.3%]), subretinal hemorrhages (2 eyes [3.3%]), serous retinal detachment (3 eyes [5%]), macular star (2 eyes [3.3%]), cystoid macular edema (1 eye [1.7%]), optic disc edema (1 eye [1.7%]), branch retinal artery occlusion (1 eye [1.7%]), optic disc staining (30 eyes [50%]), retinal vascular leakage (27 eyes [45%]), delayed filling in a branch retinal vein (1 eye [1.7%]), and multiple hypofluorescent choroidal dots (10 eyes [16.7%]). One eye (1.7%) had retinal neovascularization at the 6-month follow-up examination. All posterior segment findings at the acute stage resolved in 3 to 10 weeks, and the final visual acuity was 20/20 in 42 of 45 affected eyes (93.3%). Retinal pigment epithelium changes developed in 9 eyes (15%), with resolved full-thickness white retinal lesions. No other abnormalities were noted in the eye with retinal neovascularization over a further follow-up of 6 months. CONCLUSION: Posterior segment involvement, frequently asymptomatic, is common in patients with acute MSF. Because the diagnosis can be easily overlooked, a careful dilated funduscopic examination, complemented by fluorescein angiography in selected cases, is recommended. Mild vitritis, retinal vasculitis, optic disc staining, white retinal lesions, retinal hemorrhages, and multiple hypofluorescent choroidal dots are the most common manifestations of MSF. Posterior segment changes in a patient with fever and/or skin rash living in or returning from a specific endemic area, especially during the spring or summer, strongly suggest R. conorii infection.     

A case of optic nerve atrophy with severe disc cupping after methanol poisoning

We report a rare case of optic nerve atrophy with severe disc cupping resulting from methanol poisoning. A 30-year-old man presented to the hospital complaining of decreased visual acuity in both eyes a day after drinking alcohol containing methanol. His initial visual acuity allowed for only visualizing hand motion and not corrected in either eye. Initial intraocular pressure was within normal limits in both eyes. Initial fundus examination showed optic disc swelling in both eyes. Four years later, he visited our hospital for an eye evaluation. Visual acuity in both eyes still only allowed for visualizing hand motion. No nystagmus was observed in either eye during the optokinetic nystagmus test, and no waves were found in a visual evoked potential test. No specific change was noted on brain magnetic resonance imaging. On fundus examination, there was disc pallor in both eyes and disc cupping with a high cup/disc (C/D) ratio above 0.9 in the left eye. C/D ratio of the right eye was 0.5. Methanol poisoning may induce glaucomatous disc cupping in the late stage as well as optic atrophy. One possible mechanism of disc cupping is ganglion cell loss due to acute demyelination of the retrobulbar optic nerve. This report is the first photographic evidence of methanol induced optic disc cupping in Korea.     

The influence of age, gender, refractive error, and optic disc size on the optic disc configuration in Japanese normal eyes

PURPOSE: To investigate the influence of age, gender, refractive error, and optic disc size on optic disc configuration in Japanese normal eyes. METHODS: Ninety-two eyes from 92 visually normal Japanese subjects (mean refractive error+/-SD: -1.26+/-2.25 D, range -8 D to +3 D) were examined using a confocal scanning laser tomograph, TopSS. The following disc parameters were investigated: disc size, total or quadrant C/D area ratio and neuroretinal rim area, half-depth area, volume below, and average cup depth. RESULTS: The disc diameter ( mean+/-SD: 1.84+/-0.16 mm) and disc size showed highly significant correlations with the C/D ratio (p<0.001) and the neuroretinal rim area (p<0.001). No other correlation was observed. CONCLUSION: These results indicate that the optic disc diameter and disc size have higher correlations with the optic disc configuration than age, gender, and refractive error in Japanese. These results are similar to those data reported for eyes of Caucasians or Afro Americans, and should be considered when optic discs are evaluated.     

The effect of the intraocular pressure reduction on glaucomatous disc changes and visual field defects]

The authors prospectively studied changes in the optic disc and visual field associated with intraocular pressure (IOP) reduction for one year after surgery in 12 primary open-angle glaucoma eyes of 7 patients who underwent trabeculectomy because of elevated IOP despite maximum tolerable medical therapy and whose cup volume was demonstrated to be decreased at 3 or 6 months after surgery. Topographic parameters including C/D ratio, rim area and cup volume were determined by the Optic Nerve Head Analyzer plus (Rodenstock). The 30-2 central threshold field was obtained with a Humphrey Field Analyzer at the same time. Mean deviation (MD), corrected pattern standard deviation (CPSD) and total deviation (TD) were used to evaluate visual field changes. Significant improvement of C/D ratio, rim area and cup volume and significant IOP reduction were noted at 1 year after surgery as compared with preoperative baseline value (p less than 0.01). Also the MD was significantly decreased at 1 year after surgery, compared with the preoperative baseline value (p less than 0.05). There was a significant negative correlation between the preoperative MD and the percent change of the MD at 1 year after surgery (r = -0.80, p less than 0.01). Our results suggest that the decrease of optic disc cupping can persist over one year after surgery and that the early visual field defects in glaucoma eyes can gradually improve in association with the decrease of cupping.