Anastasios Anastasakis

Clinical value, normative retinal sensitivity values, and intrasession repeatability using a combined spectral domain optical coherence tomography/scanning laser ophthalmoscope microperimeter

PurposeTo establish normative values for macular light sensitivity and to determine the intrasession fluctuation of perimetric responses using the OPKO/OTI microperimeter.MethodsA total of 32 visually normal subjects participated in the study. A standardized grid pattern was used for testing, which consisted of 28 points arranged concentrically in three circles that occupied an area of 11° (in diameter) within the central macula. Each subject participated in at least two tests. Parameters evaluated included: overall mean macular sensitivity for test 1 and 2, overall difference in mean macular sensitivity between tests, and the mean sensitivity for each circle. The relationship between sensitivity and age was also examined.ResultsThe overall median sensitivity for test 1 was 16.8 decibels (dB) and for test 2 was 16.9 dB. The median sensitivities for test 1 and test 2 were not significantly different (P=0.72). The mean intrasession sensitivity difference was 0.13 dB. The variability of the sensitivity difference between tests decreased as mean sensitivity increased. The sensitivity values averaged across the two tests for inner, middle, and outer circles ranged from 14.3 to 18.8 dB (median value of 16.9 dB), 13.8–18.3 dB (median value of 17.2 dB), and 11.3–18.3 dB (median value of 16.6 dB), respectively. Linear regression analysis showed a 0.5 dB sensitivity loss for each decade of life.ConclusionWe documented a narrow range of intrasession fluctuation using the OPKO/OTI microperimeter. The establishment of normative sensitivity values will facilitate monitoring the loss of macular visual function in patients with retinal disease.

Evaluation of retinal nerve fiber layer thickness in patients with retinitis pigmentosa using spectral-domain optical coherence tomography

Purpose To measure the peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography in patients with retinitis pigmentosa. Methods Fifty eyes of 30 patients with retinitis pigmentosa underwent a complete ocular examination, including best-corrected visual acuity using a Snellen chart, slit-lamp biomicroscopic examination, and Goldmann applanation intraocular pressure measurement. Dilated fundus examination was performed using both direct and indirect ophthalmoscopy. In addition, all patients underwent peripapillary RNFL thickness measurements using an OPKO spectral-domain optical coherence tomography (OPKO Instrumentations, Miami, FL). Results The mean (±SD) age of the study cohort was 45.8 (±16.3) years. Of the 50 eyes, 18 (36%) showed a thinning of the peripapillary RNFL in 1 or more quadrants and 21 (42%) showed a thickening of the peripapillary RNFL in 1 or more quadrants. Four eyes (8%) showed both thinning and thickening of the peripapillary RNFL thickness. The overall circumferential RNFL thickness of the 14 eyes that showed only thinning in at least 1 quadrant was 78.78 &mgr;m. For the 17 eyes that showed only thickening in at least 1 quadrant, the RNFL thickness was 119.69 &mgr;m. The values of the eyes with thinning and the eyes with thickening were significantly different from normal (t = 6.31 and P < 0.01 for thickening; t = 3.62 and P < 0.01 for thinning). Conclusion Using spectral-domain optical coherence tomography testing, we demonstrated in the current study that the peripapillary RNFL thickness in patients with RP can be decreased, increased, or maintained within normal limits. Assessment of the RNFL thickness seems prudent in these patients, particularly for identifying notable degrees of RNFL thinning in those being considered for future therapeutic trials.

Microperimetry and OCT findings in female carriers of choroideremia

Purpose: To evaluate structural retinal changes and macular function by a combined spectral domain optical coherence tomography/ scanning laser ophthalmoscope (OCT/ SLO) microperimetry device in choroideremia carriers. Methods and Materials: Ten choroideremia carriers were included in the study. All subjects had a complete ophthalmic examination in addition to Goldmann kinetic visual fields, OCT and microperimetry testing on a commercially available Spectral Domain (SD) OCT/SLO combination system. Results: Microperimetry results demonstrated focal areas of threshold abnormalities in 50% of the subjects. OCT findings show subtle retinal pigment epithelium (RPE) irregularities with attenuation more pronounced outside the macular region. Conclusions: Long term follow up with microperimetric testing could be useful in monitoring any progressive loss of retinal function in choroideremia carriers.

Macular vitelliform lesion in desferrioxamine-related retinopathy

To report a case of a macular vitelliform lesion associated with desferrioxamine treatment. Ocular, electrophysiological, psychophysical, perimetric, fluorescein angiographic, fundus autofluorescence, and spectral-domain OCT examinations were obtained on a 45-year-old Caucasian woman with thalassemia major treated with blood transfusions and desferrioxamine. The patient was observed to have a vitelliform macular lesion in the right eye with a hypopigmented macular lesion and retinal pigment mottling in the left. At the most recent follow-up visit, best-corrected visual acuity was 20/70 in the right eye and 20/25 in left. Full-field electroretinogram (ERG) testing showed normal cone and rod responses. Mild localized elevations of rod psychophysical thresholds were found. A vitelliform macular lesion can develop in patients treated with desferrioxamine. Some such patients may not show diffuse photoreceptor cell functional loss as determined by electrophysiological testing.

Spectral-domain OCT peripapillary retinal nerve fibre layer thickness measurements in patients with stargardt disease

Aims To evaluate the presence of peripapillary retinal nerve fibre layer (RNFL) defects in patients with Stargardt disease by using spectral-domain optical coherence tomography (SD-OCT). Methods Fifty-two eyes of 27 patients with Stargardt disease underwent peripapillary RNFL thickness measurements using SD-OCT. Results Twenty-seven patients with Stargardt disease were enrolled. Their mean (±SD) age was 38.3 (14.7) years. Fourteen patients (51.9%) showed a thinning of the peripapillary RNFL in one or more quadrants in at least one eye, and four patients (14.8%) in both eyes. Five patients (18.5%) showed a thickening of the peripapillary RNFL in at least one eye, and four patients (14.8%) in both eyes. Conclusion This study demonstrated the presence of defects in the peripapillary RNFL thickness in patients with Stargardt disease by using SD-OCT. It would be clinically prudent that Stargardt patients considered for various treatment options be considered for RNFL thickness measurements.

Structural and Functional Measures of Inner Retinal Integrity Following Visual Acuity Improvement in a Patient with Hereditary Motor and Sensory Neuropathy Type VI

Purpose: To report measures of inner retinal integrity following improvement in visual acuity and visual fields in a patient with hereditary motor and sensory neuropathy type VI (HMSN VI). Case Report: The patient is a Caucasian male with HMSN VI (type 2A Charcot-Marie-Tooth disease and associated optic atrophy) and a c.1090C→T (p.R364W) mutation in the mitofusin 2 (MFN2) gene. The patient’s best-corrected visual acuity improved from 20/200 (OD) and 20/400 (OS) at the initial visit to 20/25 in each eye when tested 7 years later. The visual field defects in both eyes that were present at the initial visit were absent at the follow-up visit. The structural integrity of the inner retina was assessed by an evaluation of retinal nerve fiber layer thickness (RNFLT) using optical coherence tomography (OCT), and the functional integrity was assessed by the amplitude of the photopic negative response (PhNR) of the electroretinogram (ERG). At the follow-up visit, the patient’s RNFLT was less than the 5th percentile for control subjects in the superior and inferior quadrants OD and in one sector of the temporal quadrant OS, but was within normal limits elsewhere. The PhNR amplitude of each eye was below the lower limit of the normal range. Conclusion: The abnormally low PhNR amplitudes and abnormally thin RNFL in certain quadrants of the retina following improvement of visual acuity and visual fields to near-normal values illustrates the potential usefulness of assessing the structure and function of the inner retina in HMSN VI patients.

Electroretinographic Findings in a Patient with Congenital Stationary Night Blindness Due to a Novel NYX Mutation

ABSTRACT Purpose: To document a novel NYX gene mutation in a patient with X-linked complete congenital stationary night blindness and to describe this patient’s electroretinogram (ERG) characteristics. Methods: ERGs were recorded from a 17-year-old male with a previously unreported NYX mutation (819G > A) that results in a missense codon change (Trp237Ter). ERGs were recorded in response to brief-flash stimuli, 6.33-Hz sawtooth flicker, and sinusoidal flicker ranging from 6.33–100 Hz. The omitted stimulus response (OSR) of the flicker ERG, which is thought to be generated within the ON-pathway, was also assessed. Results: The patient’s single-flash responses were consistent with previously documented NYX ERG characteristics, including a high-luminance flash response that was electronegative under dark-adapted conditions and a square-like a-wave followed by an abnormally shaped positive potential under light-adapted conditions, both of which are consistent with an ON-pathway deficit. Further evidence for an ON-pathway deficit included: (1) ERGs to rapid-on sawtooth flicker in which b-wave amplitude was reduced more than a-wave amplitude, and (2) responses to sinusoidal flicker that lacked the normal amplitude minimum and phase inflection near 12 Hz, ERG characteristics that are like those of patients with other NYX mutations. Novel findings included a pronounced amplitude attenuation for sinusoidal flicker at frequencies above approximately 50 Hz and an absent OSR, suggesting ON-pathway dysfunction at high frequencies. Conclusion: The substantial loss of ERG amplitude and apparent ON-pathway dysfunction at high temporal frequencies distinguish this patient with a Trp237Ter NYX mutation from those with other previously reported NYX mutations.

Educational Levels in Patients with Stargardt Disease

PURPOSE To assess the highest educational level attained by patients with Stargardt disease and clinically significant visual impairment. DESIGN Cross-sectional assessment. METHODS Patients with Stargardt disease and clinically significant visual impairment (documented best-corrected visual acuity of 20/70 or worse in each eye either before or up to the age of 22 years) were included in the study. Information concerning the highest level of education attained was obtained for all participants by an interview. RESULTS Of the 33 participants, 32 completed high school. Either an associates or bachelors degree was attained by 21 patients (63.6%), whereas 3 patients (9.1%) were enrolled in college at the time of the interview. Further, a postgraduate degree (masters or doctorate) was attained by 7 patients (21.2%). CONCLUSIONS Our findings document that the potential for attaining a higher degree of academic education beyond high school does not seem to be precluded by clinically significant visual impairment in Stargardt patients. This information can be useful for visual practitioners when counseling these patients and their families.

Spontaneous Regression of Choroidal Neovascularization in a Patient with Pattern Dystrophy

Purpose. To present a case of a patient with pattern dystrophy (PD) associated choroidal neovascularization (CNV) that resolved spontaneously without treatment. Methods. A 69-year-old male patient was referred to our unit, for evaluation of a recent visual loss (metamorphopsias) in his left eye. Fundus examination, fundus autofluorescence imaging, and fluorescein angiography showed a choroidal neovascular membrane in his left eye. Since visual acuity was satisfactory the patient elected observation. Clinical examination and OCT testing were repeated at 6 and 12 months after presentation. Results. Visual acuity remained stable at the level of 0.9 (baseline BCVA) during the follow-up period (12 months). Repeat OCT testing showed complete spontaneous regression of the choroidal neovascular membrane without evidence of intra- or subretinal fluid in both follow-up visits. Conclusions. Spontaneous regression of choroidal neovascularization can occur in patients with retinal dystrophies and associated choroidal neovascular membranes. The decision to treat or observe these patients relies strongly on the presenting visual acuity, since, in isolated instances, spontaneous resolution of choroidal neovascularization may occur.

VISUAL ACUITY LOSS IN RECESSIVE RETINITIS PIGMENTOSA AND ITS CORRELATION WITH MACULAR LESIONS

Purpose: To determine the visual acuity loss in patients with autosomal recessive retinitis pigmentosa and its relation to the presence of macular lesions. Methods: A total of 145 patients were included in the visual acuity analysis, and 139 patients were included in the analysis of their macular status. Patients with a history of parental consanguinity or an affected sister and parents unaffected with retinitis pigmentosa were considered as having an autosomal recessive mode of inheritance. Results: Regardless of age, 68 patients (47%) had visual acuity of 20/40 or better, 109 (75%) had better than 20/200 in at least 1 eye, and 36 (25%) had an acuity of 20/200 or worse in both eyes. An evaluation of the macular status demonstrated that 55 patients (39.6%) had no macular lesion and 77 (55.4%) had an atrophic lesion (either bulls-eye or geographic). Seventy-five percent of patients with no macular lesion had a visual acuity of 20/40 or better and 34 patients (44%) with an atrophic lesion had a visual acuity better than 20/70. Conclusion: These data can be useful to counsel patients on the potential visual acuity impairment likely to be observed at different ages and identify the association of visual acuity loss with macular changes.