Doc Ophthalmol DOI 10.1007/s10633-014-9472-8
CLINICAL CASE REPORT
Optical coherence tomography and electrophysiological findings in torpedo maculopathy Luca Buzzonetti • Sergio Petroni • Gino Catena Giancarlo Iarossi
•
Received: 13 August 2014 / Accepted: 2 December 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose To describe the morphofunctional findings in a 6-year-old child with a unilateral lesion of the temporal macula called ‘‘torpedo maculopathy’’ throughout a 1-year follow-up. Methods Evaluation of retinal morphology and function was assessed by means of spectral-domain OCT scans, best-corrected visual acuity, full-field flash electroretinogram (ERG), multifocal electroretinogram (mfERG) and pattern visual evoked potentials (VEP). Patient was examined every 4 months for a 1-year follow-up time. Results Torpedo maculopathy consisted in a sharply demarcated hypopigmented oval iuxta-macular lesion (1.5 DD wide 9 0.7 DD high). The baseline visual acuity of the affected eye was 20/25. OCT showed a sensorial retinal detachment in correspondence with the torpedo lesion. Pattern VEPs revealed a reduced response in left eye, as compared to contralateral eye. Full-field flash ERGs amplitude was normal in both eyes. Multifocal ERG response was reduced at all sites, more significantly at the site of the lesion in the eye with torpedo maculopathy and normal in fellow eye. Visual acuity, fundoscopic evaluation, OCT scans
L. Buzzonetti S. Petroni (&) G. Catena G. Iarossi Ophthalmology Department, Bambino Gesu` IRCSS Children’s Hospital, Via Torre di Palidoro snc, 00050 Passoscuro, Rome, Italy e-mail: [email protected]
and electrophysiological tests showed no changes from baseline throughout the follow-up time. Conclusions Torpedo maculopathy, although known as benign, may affect visual function if macular involvement is associated with neuroretinal detachment. Keywords Torpedo maculopathy Optical coherence tomography Electroretinogram Visual evoked potentials
Introduction A focal congenital abnormality of the retinal pigment epithelium (RPE) consisting in an asymptomatic oval lesion located close to the temporal portion of the macula was first described by Roseman and Gass in 1992 [1]. On account of its characteristic torpedo-like shape with the tip pointing toward the foveola and the presence of a tail, Daily coined the term ‘‘torpedo maculopathy’’ to describe this congenital nevus of the RPE [2]. There has yet to be any statistical data on the incidence or prevalence of torpedo maculopathy with respect to gender, race or other demographics. Histopathological studies of this particular lesion have never been reported, and so its etiology remains speculative. Some authors [3] have suggested that abnormal choroidal development or ciliary vasculature development might lead to the localized, nonprogressive RPE lesion. The uniform location and size of
123
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this condition point toward a congenital defect at a precise time during fetal development of the RPE. Only in few studies, the morphofunctional changes of the torpedo lesion was carefully assessed by means of optical coherence tomography [4–8] (OCT), electrophysiology [9, 10] and microperimetry [8]. Regarding OCT examination, Sanabria et al. [4] showed a thinning of the retinal tissues above the torpedo-like lesion with RPE and choroidal hyperreflectivity and photoreceptor loss. Su et al. [5] found a sensory retinal detachment overhanging the lesion, whereas Golchet et al. [6] reported a cleft in the area of the lesion with the ‘‘outer retinal layer thinned with abnormal material on the back surface and degenerated photoreceptors and loss of outer segments’’ at high-resolution OCT test (Heidelberg Engineering, Heidelberg, Germany). OCT features of torpedo maculopathy also include an increased reflectivity of the choroid [7]. Electroretinogram [8] and electrooculogram [8, 9] were reported as normal. Macular microperimetry showed reduced retinal sensitivity along the pigmented margins of the lesion with normal values over the lesion [10].
Materials and methods A 6-year-old Caucasian boy was referred for routine examination. Medical history was unremarkable. On examination, the uncorrected visual acuity was 20/20 in the right eye and 20/25 in the left eye. Pupils were equal, round and reactive to light with no afferent pupillary defect. Slit-lamp biomicroscopy revealed no abnormalities of the anterior segment. Dilated fundus examination revealed, in the left eye, a sharply demarcated oval chorioretinal lesion, located temporally to the fovea (Fig. 1), with a characteristic torpedo-like shape. The surrounding retinal and choroidal tissues and periphery were normal. The fundoscopic examination of the right eye was unremarkable.
OCT The OCT–SLO system (Optos, Scotland, UK) used in the study is a noncontact, noninvasive device indicated for 3D imaging and measurement of posterior ocular structures; its axial and transverse resolutions are \6 and 20 lm, respectively. It uses light generated by an infrared broadband superluminescent diode with a
123
center wavelength of 830 nm. The OCT scan patterns used were line scan (B-Scan) and raster B-Scan.
ERG Retimax instrument (CSO, Firenze, Italy) was used for the mfERG and full-field flash ERG assessment in the protocol session. Multifocal electroretinogram was performed according to the guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV). [11] The multifocal stimulus, consisting of 61-scaled hexagons, was displayed on a high-resolution, black-and-white monitor (size 4200 ) with a frame rate of 600 Hz. The array of hexagons subtended 50° of visual field. Each hexagon was independently alternated between black (0.03 cd/m2) and white (120 cd/m2) according to a binary m-sequence. This resulted in a contrast of 99,725 % according to the Michelson contrast formula. The luminance of the central fixation cross, red color (used as target) was 0, 5 cd/m2. The m-sequence had 61 elements and total recording time was approximately 4 min. Total recording time was divided into eight segments. Between segments, the subject was allowed to rest for a few seconds. At every mfERG examination, each patient positively reported that he/she could clearly perceive the cross-fixation target. The eye’s position was monitored by a video system in the screen of the computer. In all patients, pupils were maximally pharmacologically dilated with 1 % tropicamide to a diameter of 7–8 mm. Pupil diameter was measured by an observer (GI) by means of a ruler and a magnifying lens and stored for each tested eye. The cornea was anesthetized with 1 % dicaine. The HK loops ring fiber electrodes were used to record mfERGs. A small Ag/AgCl skin earth electrode was placed at the center of the forehead. The contralateral eye was occluded to help suppress blinking. Interelectrode resistance was \3,000 ohm. The signal was amplified (gain 50.000) and filtered (band pass 1–100 Hz). After automatic rejection of artifacts (by Retimax software), the first order kernel response, K1, was examined. We analyzed the average response amplitude densities (RAD, expressed in nV/deg2) of N1 peak (from baseline) and between the first negative peak, N1, and the first positive peak, P1, and the N1 and P1 implicit times (in ms) obtained from five concentric annular retinal regions (rings) centered on the fovea. Therefore, we
Doc Ophthalmol Fig. 1 Top: optical coherence tomography (OCT) of the macular torpedo-like lesion. OCT scan shows a foveal sensory retinal detachment with overlying thinning of the retina. Bottom right: Welldefined hypopigmented lesion with a pigmented margin and a tip pointed toward the center of the macula. There are adjacent hypopigmented spots temporal to the torpedoshaped lesion. Bottom left: Infrared fundus image of the torpedo lesion
analyzed the N1–P1 RADs derived from 0° to 2.5° (ring 1, R1), from 2.5° to 5° (ring2, R2), from 5° to 10° (ring 3, R3), from 10° to 15° (ring 4, R4) and from 15° to 25° (ring 5, R5). Full-field flash ERGs were recorded using the same procedure according to the guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV) [12].
VEP Visual stimuli consisted of checkerboard patterns (a single check edge subtending 60 min of arc; contrast 99 %; mean luminance 60 cd/m2) generated on a monitor subtending 26° and reversed in contrast at the rate of two reversals per second. The stimulation was monocular, with full occlusion of the fellow eye. To maintain stable fixation, a small red target was (0°, 5°) was placed in the center of the stimulation field. VEPs were recorded by cup-shaped Ag/AgCl electrodes placed over the scalp two cm above the inion (Oz) with the reference in Fpz and the ground on the mastoid. The time-to-peak (in ms) and peak-to-peak amplitude (in lV) of major VEP components (i.e., N75, P100 and N145) were measured.
Results The OCT scans showed a sensory retinal detachment with overlying thinning of the retina, photoreceptor loss and disruption in the underlying retinal pigment epithelium (RPE)/Bruch’s complex. Diffuse high reflectivity in the overlying retina indicated the potential for some interruption in the neurosensory retina. (Fig. 1). Full-field flash ERGs had normal amplitude response in both eyes. Photopic response showed a slight interocular difference but maintaining an amplitude response within normal limits in the affected eye (Fig. 2). Multifocal ERG responses were reduced at all the analyzed rings in the eye with torpedo maculopathy and normal in fellow eye. A selective further reduction in the response was noted in the temporal sector, corresponding to the anatomical retinal lesion. Analysis of the retinal quadrant mean amplitude response revealed a statistically significant difference (P \ 0.02) between the temporal quadrants, while mean amplitude difference was nonstatistically significant for the other quadrants. Pattern VEP showed a reduced response in left eye, as compared to contralateral eye, with a normal P100 time-to-peak (Fig. 3). One year after the initial presentation, the visual acuity, fundoscopic evaluation, OCT scans and ERG/
123
Doc Ophthalmol Fig. 2 Full-field ERGs showing normal amplitude response in both eyes. A slight interocular difference in amplitude can be noted in photopic ERG
VEP assessments showed no modification from baseline.
Discussion Torpedo maculopathy is a congenital lesion of the RPE characterized by a very unique shape and location. So far, the largest case series has been published by Golchet et al. [6] and included the medical records of 13
123
patients sharing similar features after evaluation by fluorescein angiography, autofluorescence and OCT. The differential diagnosis must include several other congenital lesions of the RPE [1, 12], including combined hamartoma of the retina and RPE, congenital simple hamartoma of the RPE and particularly the congenital hypertrophy of the RPE (CHRPE) linked to Gardner’s syndrome, a dominantly inherited familial cancer syndrome that includes familial adenomatous polyposis and various soft tissue tumors. Those lesions
Doc Ophthalmol Fig. 3 Contour maps and underlying response arrays showing the significant amplitude loss with additional reduction in the temporal sector of the affected eye, corresponding to the anatomical retinal lesion, as compared to contralateral eye. Pattern VEP responses showing the interocular difference in amplitude with normal P-100 time-to-peak
associated with Gardner’s syndrome tend to be bilateral, with multiple solitary lesions that are located away from the macula, much smaller and more irregular in shape. In our clinical case, the characteristic shape and the location in the temporal macula suggested the diagnosis of torpedo maculopathy.
Even if patients with torpedo maculopathy are typically asymptomatic and have normal vision [6], our patient presented a reduction in visual acuity at baseline. Such functional deficit was partially due to the evidence of retinal dysfunction as shown by the functional and morphologic tests. OCT scans showed
123
Doc Ophthalmol
the presence of the retinal alterations such as neuroretinal retrofoveal detachment, disruption of the photoreceptor layer and retinal thinning. Pattern VEP showed a reduced response in left eye, as compared to contralateral eye, which was maintained along the follow-up time. Full-field flash ERGs showed normal amplitude response in both eyes. Multifocal ERG showed reduced responses at all the analyzed rings in the eye with torpedo maculopathy and normal responses in the fellow eye. Such reduction was more prominent for the temporal sector of the macula corresponding to the affected retinal area. To our knowledge, no previous studies reported the evidence of visual dysfunction in patients with torpedo maculopathy. The morphological and functional alterations seen on OCT and electrophysiological tests might suggest that this rare congenital retinal pathology could represent a potential cause of visual deficit if the foveal area is involved. As previously proposed [13], given the nature of these lesions, it is recommended that patients with large lesions, having irregular pigmented clumps with ‘‘fish-tails,’’ be examined with greater frequency to evaluate the presence of ultrastructural and functional macular abnormalities. mfERG and OCT may represent a useful tool to evaluate and correlate functional alterations with morphological changes of an observed lesion associated with visual dysfunction.
2.
3.
4. 5.
6. 7.
8.
9.
10. 11.
12.
References 1. Roseman RL, Gass JD (1992). Hypopigmented nevus of the retinal pigment epithelium in the macula. Arch Ophthalmol
123
13.
110(10):1358-9. Erratum in: Arch Ophthalmol. 1992; 110(12):1762 Daily MJ (1993) Torpedo maculopathy or paramacular spot syndrome. In: New Dimensions in Retina Symposium, Chicago, p. 7 Shields CL, Guzman JM, Shapiro MJ, Fogel LE, Shields JA (2010) Torpedo maculopathy at the site of the fetal ‘‘bulge’’. Arch Ophthalmol 128(4):499–501 Sanabria M, Coco R, Sanchidrian M (2008) OCT findings in torpedo maculopathy. Retin Cases Brief Rep 2(2):109–111 Su Y, Gurwood AS (2010) Neurosensory retinal detachment secondary to torpedo maculopathy. Optometry 81(8): 405–407 Golchet PR, Jampol LM, Mathura JR Jr, Daily MJ (2010) Torpedo maculopathy. Br J Ophthalmol 94(3):302–306 Villegas VM, Schwartz SG, Flynn HW Jr, Capo´ H, Berrocal AM, Murray TG, Harbour JW (2014) Distinguishing torpedo maculopathy from similar lesions of the posterior segment. Ophthalmic Surg Lasers Imaging Retina 45(3): 222–226 Pilotto E, Zannin ME, Convento E, Cortese M, Midena E (2013) Torpedo maculopathy: a morphofunctional evaluation. Int Ophthalmol 33:71–74 Rigotti M, Babighian S, Carcereri De Prati E, Marchini G (2002) Three cases of a rare congenital abnormality of the retinal pigment epithelium: torpedo maculopathy. Ophthalmologica 216:226–227 Cullen C, Zaborowski AG (2013) A case report of torpedo maculopathy in an African boy. J AAPOS 17(6):625–626 Hood DC, Bach M, Brigell M, Keating D, Kondo M, Lyons JS, Marmor MF, McCulloch DL, Palmowski-Wolfe AM, International Society For Clinical Electrophysiology of Vision (2012) ISCEV standard for clinical multifocal electroretinography (mfERG) (2011 edition). Doc Ophthalmol 124(1):1–13 Marmor MF, Fulton AB, Holder GE, Miyake Y, Brigell M, Bach M (2009) Standard for clinical electroretinography. Doc Ophthalmol 118:69–77 Teitelbaum BA, Hachey DL, Messner LV (1997) Torpedo maculopathy. J Am Optom Assoc 68(6):373–376
CLINICAL CASE REPORT
Optical coherence tomography and electrophysiological findings in torpedo maculopathy Luca Buzzonetti • Sergio Petroni • Gino Catena Giancarlo Iarossi
•
Received: 13 August 2014 / Accepted: 2 December 2014 Ó Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose To describe the morphofunctional findings in a 6-year-old child with a unilateral lesion of the temporal macula called ‘‘torpedo maculopathy’’ throughout a 1-year follow-up. Methods Evaluation of retinal morphology and function was assessed by means of spectral-domain OCT scans, best-corrected visual acuity, full-field flash electroretinogram (ERG), multifocal electroretinogram (mfERG) and pattern visual evoked potentials (VEP). Patient was examined every 4 months for a 1-year follow-up time. Results Torpedo maculopathy consisted in a sharply demarcated hypopigmented oval iuxta-macular lesion (1.5 DD wide 9 0.7 DD high). The baseline visual acuity of the affected eye was 20/25. OCT showed a sensorial retinal detachment in correspondence with the torpedo lesion. Pattern VEPs revealed a reduced response in left eye, as compared to contralateral eye. Full-field flash ERGs amplitude was normal in both eyes. Multifocal ERG response was reduced at all sites, more significantly at the site of the lesion in the eye with torpedo maculopathy and normal in fellow eye. Visual acuity, fundoscopic evaluation, OCT scans
L. Buzzonetti S. Petroni (&) G. Catena G. Iarossi Ophthalmology Department, Bambino Gesu` IRCSS Children’s Hospital, Via Torre di Palidoro snc, 00050 Passoscuro, Rome, Italy e-mail: [email protected]
and electrophysiological tests showed no changes from baseline throughout the follow-up time. Conclusions Torpedo maculopathy, although known as benign, may affect visual function if macular involvement is associated with neuroretinal detachment. Keywords Torpedo maculopathy Optical coherence tomography Electroretinogram Visual evoked potentials
Introduction A focal congenital abnormality of the retinal pigment epithelium (RPE) consisting in an asymptomatic oval lesion located close to the temporal portion of the macula was first described by Roseman and Gass in 1992 [1]. On account of its characteristic torpedo-like shape with the tip pointing toward the foveola and the presence of a tail, Daily coined the term ‘‘torpedo maculopathy’’ to describe this congenital nevus of the RPE [2]. There has yet to be any statistical data on the incidence or prevalence of torpedo maculopathy with respect to gender, race or other demographics. Histopathological studies of this particular lesion have never been reported, and so its etiology remains speculative. Some authors [3] have suggested that abnormal choroidal development or ciliary vasculature development might lead to the localized, nonprogressive RPE lesion. The uniform location and size of
123
Doc Ophthalmol
this condition point toward a congenital defect at a precise time during fetal development of the RPE. Only in few studies, the morphofunctional changes of the torpedo lesion was carefully assessed by means of optical coherence tomography [4–8] (OCT), electrophysiology [9, 10] and microperimetry [8]. Regarding OCT examination, Sanabria et al. [4] showed a thinning of the retinal tissues above the torpedo-like lesion with RPE and choroidal hyperreflectivity and photoreceptor loss. Su et al. [5] found a sensory retinal detachment overhanging the lesion, whereas Golchet et al. [6] reported a cleft in the area of the lesion with the ‘‘outer retinal layer thinned with abnormal material on the back surface and degenerated photoreceptors and loss of outer segments’’ at high-resolution OCT test (Heidelberg Engineering, Heidelberg, Germany). OCT features of torpedo maculopathy also include an increased reflectivity of the choroid [7]. Electroretinogram [8] and electrooculogram [8, 9] were reported as normal. Macular microperimetry showed reduced retinal sensitivity along the pigmented margins of the lesion with normal values over the lesion [10].
Materials and methods A 6-year-old Caucasian boy was referred for routine examination. Medical history was unremarkable. On examination, the uncorrected visual acuity was 20/20 in the right eye and 20/25 in the left eye. Pupils were equal, round and reactive to light with no afferent pupillary defect. Slit-lamp biomicroscopy revealed no abnormalities of the anterior segment. Dilated fundus examination revealed, in the left eye, a sharply demarcated oval chorioretinal lesion, located temporally to the fovea (Fig. 1), with a characteristic torpedo-like shape. The surrounding retinal and choroidal tissues and periphery were normal. The fundoscopic examination of the right eye was unremarkable.
OCT The OCT–SLO system (Optos, Scotland, UK) used in the study is a noncontact, noninvasive device indicated for 3D imaging and measurement of posterior ocular structures; its axial and transverse resolutions are \6 and 20 lm, respectively. It uses light generated by an infrared broadband superluminescent diode with a
123
center wavelength of 830 nm. The OCT scan patterns used were line scan (B-Scan) and raster B-Scan.
ERG Retimax instrument (CSO, Firenze, Italy) was used for the mfERG and full-field flash ERG assessment in the protocol session. Multifocal electroretinogram was performed according to the guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV). [11] The multifocal stimulus, consisting of 61-scaled hexagons, was displayed on a high-resolution, black-and-white monitor (size 4200 ) with a frame rate of 600 Hz. The array of hexagons subtended 50° of visual field. Each hexagon was independently alternated between black (0.03 cd/m2) and white (120 cd/m2) according to a binary m-sequence. This resulted in a contrast of 99,725 % according to the Michelson contrast formula. The luminance of the central fixation cross, red color (used as target) was 0, 5 cd/m2. The m-sequence had 61 elements and total recording time was approximately 4 min. Total recording time was divided into eight segments. Between segments, the subject was allowed to rest for a few seconds. At every mfERG examination, each patient positively reported that he/she could clearly perceive the cross-fixation target. The eye’s position was monitored by a video system in the screen of the computer. In all patients, pupils were maximally pharmacologically dilated with 1 % tropicamide to a diameter of 7–8 mm. Pupil diameter was measured by an observer (GI) by means of a ruler and a magnifying lens and stored for each tested eye. The cornea was anesthetized with 1 % dicaine. The HK loops ring fiber electrodes were used to record mfERGs. A small Ag/AgCl skin earth electrode was placed at the center of the forehead. The contralateral eye was occluded to help suppress blinking. Interelectrode resistance was \3,000 ohm. The signal was amplified (gain 50.000) and filtered (band pass 1–100 Hz). After automatic rejection of artifacts (by Retimax software), the first order kernel response, K1, was examined. We analyzed the average response amplitude densities (RAD, expressed in nV/deg2) of N1 peak (from baseline) and between the first negative peak, N1, and the first positive peak, P1, and the N1 and P1 implicit times (in ms) obtained from five concentric annular retinal regions (rings) centered on the fovea. Therefore, we
Doc Ophthalmol Fig. 1 Top: optical coherence tomography (OCT) of the macular torpedo-like lesion. OCT scan shows a foveal sensory retinal detachment with overlying thinning of the retina. Bottom right: Welldefined hypopigmented lesion with a pigmented margin and a tip pointed toward the center of the macula. There are adjacent hypopigmented spots temporal to the torpedoshaped lesion. Bottom left: Infrared fundus image of the torpedo lesion
analyzed the N1–P1 RADs derived from 0° to 2.5° (ring 1, R1), from 2.5° to 5° (ring2, R2), from 5° to 10° (ring 3, R3), from 10° to 15° (ring 4, R4) and from 15° to 25° (ring 5, R5). Full-field flash ERGs were recorded using the same procedure according to the guidelines of the International Society for Clinical Electrophysiology of Vision (ISCEV) [12].
VEP Visual stimuli consisted of checkerboard patterns (a single check edge subtending 60 min of arc; contrast 99 %; mean luminance 60 cd/m2) generated on a monitor subtending 26° and reversed in contrast at the rate of two reversals per second. The stimulation was monocular, with full occlusion of the fellow eye. To maintain stable fixation, a small red target was (0°, 5°) was placed in the center of the stimulation field. VEPs were recorded by cup-shaped Ag/AgCl electrodes placed over the scalp two cm above the inion (Oz) with the reference in Fpz and the ground on the mastoid. The time-to-peak (in ms) and peak-to-peak amplitude (in lV) of major VEP components (i.e., N75, P100 and N145) were measured.
Results The OCT scans showed a sensory retinal detachment with overlying thinning of the retina, photoreceptor loss and disruption in the underlying retinal pigment epithelium (RPE)/Bruch’s complex. Diffuse high reflectivity in the overlying retina indicated the potential for some interruption in the neurosensory retina. (Fig. 1). Full-field flash ERGs had normal amplitude response in both eyes. Photopic response showed a slight interocular difference but maintaining an amplitude response within normal limits in the affected eye (Fig. 2). Multifocal ERG responses were reduced at all the analyzed rings in the eye with torpedo maculopathy and normal in fellow eye. A selective further reduction in the response was noted in the temporal sector, corresponding to the anatomical retinal lesion. Analysis of the retinal quadrant mean amplitude response revealed a statistically significant difference (P \ 0.02) between the temporal quadrants, while mean amplitude difference was nonstatistically significant for the other quadrants. Pattern VEP showed a reduced response in left eye, as compared to contralateral eye, with a normal P100 time-to-peak (Fig. 3). One year after the initial presentation, the visual acuity, fundoscopic evaluation, OCT scans and ERG/
123
Doc Ophthalmol Fig. 2 Full-field ERGs showing normal amplitude response in both eyes. A slight interocular difference in amplitude can be noted in photopic ERG
VEP assessments showed no modification from baseline.
Discussion Torpedo maculopathy is a congenital lesion of the RPE characterized by a very unique shape and location. So far, the largest case series has been published by Golchet et al. [6] and included the medical records of 13
123
patients sharing similar features after evaluation by fluorescein angiography, autofluorescence and OCT. The differential diagnosis must include several other congenital lesions of the RPE [1, 12], including combined hamartoma of the retina and RPE, congenital simple hamartoma of the RPE and particularly the congenital hypertrophy of the RPE (CHRPE) linked to Gardner’s syndrome, a dominantly inherited familial cancer syndrome that includes familial adenomatous polyposis and various soft tissue tumors. Those lesions
Doc Ophthalmol Fig. 3 Contour maps and underlying response arrays showing the significant amplitude loss with additional reduction in the temporal sector of the affected eye, corresponding to the anatomical retinal lesion, as compared to contralateral eye. Pattern VEP responses showing the interocular difference in amplitude with normal P-100 time-to-peak
associated with Gardner’s syndrome tend to be bilateral, with multiple solitary lesions that are located away from the macula, much smaller and more irregular in shape. In our clinical case, the characteristic shape and the location in the temporal macula suggested the diagnosis of torpedo maculopathy.
Even if patients with torpedo maculopathy are typically asymptomatic and have normal vision [6], our patient presented a reduction in visual acuity at baseline. Such functional deficit was partially due to the evidence of retinal dysfunction as shown by the functional and morphologic tests. OCT scans showed
123
Doc Ophthalmol
the presence of the retinal alterations such as neuroretinal retrofoveal detachment, disruption of the photoreceptor layer and retinal thinning. Pattern VEP showed a reduced response in left eye, as compared to contralateral eye, which was maintained along the follow-up time. Full-field flash ERGs showed normal amplitude response in both eyes. Multifocal ERG showed reduced responses at all the analyzed rings in the eye with torpedo maculopathy and normal responses in the fellow eye. Such reduction was more prominent for the temporal sector of the macula corresponding to the affected retinal area. To our knowledge, no previous studies reported the evidence of visual dysfunction in patients with torpedo maculopathy. The morphological and functional alterations seen on OCT and electrophysiological tests might suggest that this rare congenital retinal pathology could represent a potential cause of visual deficit if the foveal area is involved. As previously proposed [13], given the nature of these lesions, it is recommended that patients with large lesions, having irregular pigmented clumps with ‘‘fish-tails,’’ be examined with greater frequency to evaluate the presence of ultrastructural and functional macular abnormalities. mfERG and OCT may represent a useful tool to evaluate and correlate functional alterations with morphological changes of an observed lesion associated with visual dysfunction.
2.
3.
4. 5.
6. 7.
8.
9.
10. 11.
12.
References 1. Roseman RL, Gass JD (1992). Hypopigmented nevus of the retinal pigment epithelium in the macula. Arch Ophthalmol
123
13.
110(10):1358-9. Erratum in: Arch Ophthalmol. 1992; 110(12):1762 Daily MJ (1993) Torpedo maculopathy or paramacular spot syndrome. In: New Dimensions in Retina Symposium, Chicago, p. 7 Shields CL, Guzman JM, Shapiro MJ, Fogel LE, Shields JA (2010) Torpedo maculopathy at the site of the fetal ‘‘bulge’’. Arch Ophthalmol 128(4):499–501 Sanabria M, Coco R, Sanchidrian M (2008) OCT findings in torpedo maculopathy. Retin Cases Brief Rep 2(2):109–111 Su Y, Gurwood AS (2010) Neurosensory retinal detachment secondary to torpedo maculopathy. Optometry 81(8): 405–407 Golchet PR, Jampol LM, Mathura JR Jr, Daily MJ (2010) Torpedo maculopathy. Br J Ophthalmol 94(3):302–306 Villegas VM, Schwartz SG, Flynn HW Jr, Capo´ H, Berrocal AM, Murray TG, Harbour JW (2014) Distinguishing torpedo maculopathy from similar lesions of the posterior segment. Ophthalmic Surg Lasers Imaging Retina 45(3): 222–226 Pilotto E, Zannin ME, Convento E, Cortese M, Midena E (2013) Torpedo maculopathy: a morphofunctional evaluation. Int Ophthalmol 33:71–74 Rigotti M, Babighian S, Carcereri De Prati E, Marchini G (2002) Three cases of a rare congenital abnormality of the retinal pigment epithelium: torpedo maculopathy. Ophthalmologica 216:226–227 Cullen C, Zaborowski AG (2013) A case report of torpedo maculopathy in an African boy. J AAPOS 17(6):625–626 Hood DC, Bach M, Brigell M, Keating D, Kondo M, Lyons JS, Marmor MF, McCulloch DL, Palmowski-Wolfe AM, International Society For Clinical Electrophysiology of Vision (2012) ISCEV standard for clinical multifocal electroretinography (mfERG) (2011 edition). Doc Ophthalmol 124(1):1–13 Marmor MF, Fulton AB, Holder GE, Miyake Y, Brigell M, Bach M (2009) Standard for clinical electroretinography. Doc Ophthalmol 118:69–77 Teitelbaum BA, Hachey DL, Messner LV (1997) Torpedo maculopathy. J Am Optom Assoc 68(6):373–376
