face injury. Considering the onset of corneal infiltration, the cause of corneal infiltrate in this case appears to be delayed type hypersensitivity (DTH) reaction. DTH reaction takes 2 to 3 days to develop, and foreign materials act as haptens that conjugate with proteins, the complex of which combines with T lymphocytes, leading to an inflammatory response [1,2]. A previous study showed that oxidized cooking oil enhanced DTH in mice [3]. Further experimental study is needed to reveal the maturation of dendritic cells and to determine whether the DTH is triggered after cooking oil exposure. Transient myopic changes were mostly induced from sclera-choroidal inf lammation or changes in the lens-iris diaphragm [4]. An increase in K value occurred during corneal inflammation in this case. When back-calculation was applied using the clinical history method, the change in K value was well matched with the change in refraction of the corneal plane (Fig. 1C) [5]. Corneal thermal injury may cause collagen shrinkage and induce a transient steepening in the central cornea, as in conductive keratoplasty. In conclusion, we described a rare case of delayed onset transient corneal infiltration and transient myopic shift following a cooking oil burn. Clinicians should keep in mind delayed corneal changes though no ocular abnormalities are observed immediately after thermal ocular surface injury related with cooking oil.
Korean J Ophthalmol 2016;30(2):151-153 http://dx.doi.org/10.3341/kjo.2016.30.2.151
Early Retinal Changes in Hunter Syndrome According to Spectral Domain Optical Coherence Tomography Dear Editor, Mucopolysaccharidosis is an inheritable storage disease with deficiency of lysosomal enzymes that degrade glycosaminoglycans [1]. Mucopolysaccharidosis type II, also known as Hunter syndrome, is an X-linked inherited deficiency of enzyme iduronate 2-sulfatase, resulting in progressive accumulation of dermatan sulfate and heparin
Jong Ho Ahn, Dong Hyun Kim
Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, Korea E-mail (Dong Hyun Kim): [email protected]
Conflict of Interest No potential conflict of interest relevant to this article was reported.
References 1. Krachmer JH, Mannis MJ, Holland EJ, editors. Cornea. St. Louis: Elsevier Mosby; 2011. p. 1178-80. 2. Black CA. Delayed type hypersensitivity: current theories with an historic perspective. Dermatol Online J 1999;5:7. 3. Ogino H, Sakazaki F, Okuno T, et al. Oxidized dietary oils enhance immediate- and/or delayed-type allergic reactions in BALB/c mice. Allergol Int 2015;64:66-72. 4. Herbort CP, Papadia M, Neri P. Myopia and inflammation. J Ophthalmic Vis Res 2011;6:270-83. 5. Hoffer KJ. Intraocular lens power calculation for eyes after refractive keratotomy. J Refract Surg 1995;11:490-3.
sulfate [1]. In many mucopolysaccharidoses, glycosaminoglycans accumulate in the retinal pigment epithelial (RPE) cells, resulting in pronounced lysosomal distension [2]. Previous studies have revealed outer nuclear layer thinning and the absence of outer segments, as well as reduced inner segments from the anterior midperipheral retina [2,3]. However, structural changes of the retina determined by high-resolution spectral domain optical coherence tomography (SD-OCT; Spectralis, Heidelberg Engineering, Heidelberg, Germany) in the early stage of Hunter syndrome with visual impairment have not been reported. With the introduction of SD-OCT, high-resolution images of the retina and optic disc could reveal occult and early structural changes related to disease progression [4]. Herein, we report a patient with Hunter syndrome whose visual acuity decrease was associated with early outer retinal layer
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changes found on SD-OCT. A 5-year-old boy with Hunter syndrome was referred to our clinic for evaluation of ocular involvement. At initial presentation, his best corrected visual acuities were 20 / 25 in both eyes (OU). Cycloplegic refractive errors were +4.50 Dsph = -3.00 Dcyl × axis 180 in the right eye (OD) and +4.50 Dsph = -3.75 Dcyl × axis 180 in the left eye (OS). Slit lamp biomicroscopy showed clear corneas OU. Funduscopic examination was unremarkable. At the age of 9, he complained of visual acuity decrease OU. On ophthalmic examination, best corrected visual acuities were 20 / 30 OD and 20 / 50 OS. Cycloplegic refractive errors were +4.00 Dsph = -3.50 Dcyl × axis 180 OD and +4.00 Dsph = -4.25 Dcyl × axis 180 OS. Slit lamp biomicroscopy showed clear corneas OU (Fig. 1A and 1B). There was no relative afferent papillary defect. Optic disc
A
B
C
D
Fig. 1. Slit lamp biomicroscopy showed clear corneas in the right (A) and left (B) eyes. (C,D) Comparison of spectral domain optical coherence tomography (SD-OCT; Spectralis, Heidelberg Engineering, Heidelberg, Germany) scans of the macula in early stage Hunter syndrome and normal control. (C) Vertical scan images with SD-OCT of the patient’s right eye. There was marked thickening of the external limiting membrane (ELM). The ellipsoid zone (EZ) formerly known as the inner and outer segment photoreceptor junction appeared normal in thickness and contour, well distinguished from the retinal pigment epithelial layer underneath. The photoreceptor layer and retinal pigment epithelium-Bruch’s membrane complex (RPE/Bruch’s complex) showed no thinning or other abnormal change. (D) SD-OCT of the normal eye from a control subject showed four distinct high-signal bands in the outer retinal layer without foveal thickening of the ELM.
152
margins showed mild blurring. However, lumbar spinal tapping revealed normal intracranial pressure. Visual field testing with Goldmann kinetic perimetry were normal OU. On funduscopic examination, the retina looked grossly intact, but standard electroretinography revealed a reduction of scotopic responses, consistent with rod cell degeneration. Reduced b-wave amplitudes in the maximal responses and reduced oscillatory potentials were also observed OU. SD-OCT showed thickening of the external limiting membrane at the central macula, especially near the fovea (Fig. 1C and 1D). The ellipsoid line formerly known as the inner and outer segment photoreceptor junction appeared normal in thickness and contour, well distinguished from the RPE layer underneath. The peripapillary circular scan images showed a mild increase in bilateral peripapillary retinal nerve fiber layer thickness. Our study demonstrates the structural changes of the retina determined by high-resolution SD-OCT in the early stage of Hunter syndrome. Previously, Yoon et al. [3] reported high-speed, ultrahigh-resolution OCT findings of the retina in Hunter syndrome. Stratus OCT revealed a loss of photoreceptors outside the fovea and cystoid spaces within the inner nuclear layer, ganglion cell layer, and outer nuclear layer [3]. Our patient only showed thickening of the external limiting membrane with no other abnormal findings in the RPE, suggesting that changes of the outer nuclear and photoreceptor layers precede RPE abnormalities. In contrast to our study, the previous case experienced more variable ocular symptoms typical of Hunter syndrome, such as exophthalmos, hypertelorism, and bilateral visual field loss with a ring scotoma pattern, which were not found in our patient. The external limiting membrane, between photoreceptor inner segments and Müller cell apical processes, is filled with the interphotoreceptor matrix, which contains a heterogeneous collection of glycoproteins, enzymes, and glycosaminoglycans [5]. Our SD-OCT findings correlate well with previous histopathological findings in the early stage of Hunter syndrome. The typical histopathological findings reported previously, such as a total loss of RPE, an overall loss of rods and cones, and reduced outer nuclear layer with atrophic bipolar cells, are usually shown as the disease progresses [2]. In conclusion, SD-OCT can be used as a diagnostic modality to monitor patients with Hunter syndrome and to detect subclinical progression of the disease in the early stages.
Seonghwan Kim, Yung Ju Yoo, Se Joon Woo, Hee Kyung Yang Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea E-mail (Hee Kyung Yang): [email protected]
2. McDonnell JM, Green WR, Maumenee IH. Ocular histopathology of systemic mucopolysaccharidosis, type II-A (Hunter syndrome, severe). Ophthalmology 1985;92:1772-9. 3. Yoon MK, Chen RW, Hedges TR 3rd, et al. High-speed, ultrahigh resolution optical coherence tomography of the retina in Hunter syndrome. Ophthalmic Surg Lasers Imaging 2007;38:423-8.
Conflict of Interest
4. Chen TC, Cense B, Pierce MC, et al. Spectral domain optical coherence tomography: ultra-high speed, ultra-high
No potential conflict of interest relevant to this article was reported.
resolution ophthalmic imaging. Arch Ophthalmol 2005; 123:1715-20. 5. Bunt-Milam AH, Saari JC, Klock IB, Garwin GG. Zonulae adherentes pore size in the external limiting membrane of
References
the rabbit retina. Invest Ophthalmol Vis Sci 1985;26:137780.
1. Ashworth JL, Biswas S, Wraith E, Lloyd IC. Mucopolysaccharidoses and the eye. Surv Ophthalmol 2006;51:1-17.
Korean J Ophthalmol 2016;30(2):153-155 http://dx.doi.org/10.3341/kjo.2016.30.2.153
Macular Edema after Gabapentin Dear Editor, Gabapentin is an anticonvulsant and has been used to manage neuropathic pain. It was originally developed as an antiepileptic agent; however, it is now recommended as a drug of choice for the treatment of neuropathic pain. There is strong evidence that gabapentin is also effective in diabetic neuropathy and postherpetic neuralgia [1]. To the best of our knowledge, macular edema after use of gabapentin has not been reported to date. Therefore, we report a case of macular edema after gabapentin. A 71-year-old man presented with a 1 day history of visual disturbance and metamorphosis in both eyes. The patient had taken oral gabapentin (Neurontin; Pfizer, New York, NY, USA) and oral methylprednisolone (Methylon; Alvogen, Seoul, Korea) for 8 days for treatment of postherpetic neuralgia. He had no other significant medical history, except hypertension controlled by oral medication. Best-corrected visual acuity (Snellen) was 0.4 (right eye) and 0.2 (left eye), and the intraocular pressure was 9
mmHg (right eye), 11 mmHg (left eye), as determined by non-contact tonometry. Both eyes had moderate cataract. Ophthalmic examination of the anterior segments revealed no other abnormal findings. Dilated fundus examination and spectral domain optical coherence tomography revealed macular edema and serous retinal detachment of macula in both eyes (Fig. 1A-1D). Fluorescence angiography revealed fluorescein dye pooling on the macula and multiple leakages in both eyes (Fig. 1E and 1F). The patient was advised to discontinue gabapentin, and the use of the drug was stopped. Four weeks after the initial visit, best corrected visual acuity improved to 0.9 (both eye). Fundus exam and spectral domain optical coherence tomography revealed markedly improved macular edema and serous detachment in both eyes (Fig. 1G-1J). Gabapentin is an amino acid initially designed as a cyclic gamma-aminobutyric acid analogue with action as a gamma-aminobutyric acid agonist [2]. It also acts on different brain receptors by an as-yet unknown mechanism. Common adverse effects of gabapentin include dizziness, fatigue, drowsiness, sexual dysfunction, weight gain, and peripheral edema [3]. Uncommonly, gabapentin causes blurred vision and diplopia [4]. Steinhoff et al. [5] reported
153
Korean J Ophthalmol 2016;30(2):151-153 http://dx.doi.org/10.3341/kjo.2016.30.2.151
Early Retinal Changes in Hunter Syndrome According to Spectral Domain Optical Coherence Tomography Dear Editor, Mucopolysaccharidosis is an inheritable storage disease with deficiency of lysosomal enzymes that degrade glycosaminoglycans [1]. Mucopolysaccharidosis type II, also known as Hunter syndrome, is an X-linked inherited deficiency of enzyme iduronate 2-sulfatase, resulting in progressive accumulation of dermatan sulfate and heparin
Jong Ho Ahn, Dong Hyun Kim
Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, Korea E-mail (Dong Hyun Kim): [email protected]
Conflict of Interest No potential conflict of interest relevant to this article was reported.
References 1. Krachmer JH, Mannis MJ, Holland EJ, editors. Cornea. St. Louis: Elsevier Mosby; 2011. p. 1178-80. 2. Black CA. Delayed type hypersensitivity: current theories with an historic perspective. Dermatol Online J 1999;5:7. 3. Ogino H, Sakazaki F, Okuno T, et al. Oxidized dietary oils enhance immediate- and/or delayed-type allergic reactions in BALB/c mice. Allergol Int 2015;64:66-72. 4. Herbort CP, Papadia M, Neri P. Myopia and inflammation. J Ophthalmic Vis Res 2011;6:270-83. 5. Hoffer KJ. Intraocular lens power calculation for eyes after refractive keratotomy. J Refract Surg 1995;11:490-3.
sulfate [1]. In many mucopolysaccharidoses, glycosaminoglycans accumulate in the retinal pigment epithelial (RPE) cells, resulting in pronounced lysosomal distension [2]. Previous studies have revealed outer nuclear layer thinning and the absence of outer segments, as well as reduced inner segments from the anterior midperipheral retina [2,3]. However, structural changes of the retina determined by high-resolution spectral domain optical coherence tomography (SD-OCT; Spectralis, Heidelberg Engineering, Heidelberg, Germany) in the early stage of Hunter syndrome with visual impairment have not been reported. With the introduction of SD-OCT, high-resolution images of the retina and optic disc could reveal occult and early structural changes related to disease progression [4]. Herein, we report a patient with Hunter syndrome whose visual acuity decrease was associated with early outer retinal layer
151
Korean J Ophthalmol Vol.30, No.2, 2016
changes found on SD-OCT. A 5-year-old boy with Hunter syndrome was referred to our clinic for evaluation of ocular involvement. At initial presentation, his best corrected visual acuities were 20 / 25 in both eyes (OU). Cycloplegic refractive errors were +4.50 Dsph = -3.00 Dcyl × axis 180 in the right eye (OD) and +4.50 Dsph = -3.75 Dcyl × axis 180 in the left eye (OS). Slit lamp biomicroscopy showed clear corneas OU. Funduscopic examination was unremarkable. At the age of 9, he complained of visual acuity decrease OU. On ophthalmic examination, best corrected visual acuities were 20 / 30 OD and 20 / 50 OS. Cycloplegic refractive errors were +4.00 Dsph = -3.50 Dcyl × axis 180 OD and +4.00 Dsph = -4.25 Dcyl × axis 180 OS. Slit lamp biomicroscopy showed clear corneas OU (Fig. 1A and 1B). There was no relative afferent papillary defect. Optic disc
A
B
C
D
Fig. 1. Slit lamp biomicroscopy showed clear corneas in the right (A) and left (B) eyes. (C,D) Comparison of spectral domain optical coherence tomography (SD-OCT; Spectralis, Heidelberg Engineering, Heidelberg, Germany) scans of the macula in early stage Hunter syndrome and normal control. (C) Vertical scan images with SD-OCT of the patient’s right eye. There was marked thickening of the external limiting membrane (ELM). The ellipsoid zone (EZ) formerly known as the inner and outer segment photoreceptor junction appeared normal in thickness and contour, well distinguished from the retinal pigment epithelial layer underneath. The photoreceptor layer and retinal pigment epithelium-Bruch’s membrane complex (RPE/Bruch’s complex) showed no thinning or other abnormal change. (D) SD-OCT of the normal eye from a control subject showed four distinct high-signal bands in the outer retinal layer without foveal thickening of the ELM.
152
margins showed mild blurring. However, lumbar spinal tapping revealed normal intracranial pressure. Visual field testing with Goldmann kinetic perimetry were normal OU. On funduscopic examination, the retina looked grossly intact, but standard electroretinography revealed a reduction of scotopic responses, consistent with rod cell degeneration. Reduced b-wave amplitudes in the maximal responses and reduced oscillatory potentials were also observed OU. SD-OCT showed thickening of the external limiting membrane at the central macula, especially near the fovea (Fig. 1C and 1D). The ellipsoid line formerly known as the inner and outer segment photoreceptor junction appeared normal in thickness and contour, well distinguished from the RPE layer underneath. The peripapillary circular scan images showed a mild increase in bilateral peripapillary retinal nerve fiber layer thickness. Our study demonstrates the structural changes of the retina determined by high-resolution SD-OCT in the early stage of Hunter syndrome. Previously, Yoon et al. [3] reported high-speed, ultrahigh-resolution OCT findings of the retina in Hunter syndrome. Stratus OCT revealed a loss of photoreceptors outside the fovea and cystoid spaces within the inner nuclear layer, ganglion cell layer, and outer nuclear layer [3]. Our patient only showed thickening of the external limiting membrane with no other abnormal findings in the RPE, suggesting that changes of the outer nuclear and photoreceptor layers precede RPE abnormalities. In contrast to our study, the previous case experienced more variable ocular symptoms typical of Hunter syndrome, such as exophthalmos, hypertelorism, and bilateral visual field loss with a ring scotoma pattern, which were not found in our patient. The external limiting membrane, between photoreceptor inner segments and Müller cell apical processes, is filled with the interphotoreceptor matrix, which contains a heterogeneous collection of glycoproteins, enzymes, and glycosaminoglycans [5]. Our SD-OCT findings correlate well with previous histopathological findings in the early stage of Hunter syndrome. The typical histopathological findings reported previously, such as a total loss of RPE, an overall loss of rods and cones, and reduced outer nuclear layer with atrophic bipolar cells, are usually shown as the disease progresses [2]. In conclusion, SD-OCT can be used as a diagnostic modality to monitor patients with Hunter syndrome and to detect subclinical progression of the disease in the early stages.
Seonghwan Kim, Yung Ju Yoo, Se Joon Woo, Hee Kyung Yang Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea E-mail (Hee Kyung Yang): [email protected]
2. McDonnell JM, Green WR, Maumenee IH. Ocular histopathology of systemic mucopolysaccharidosis, type II-A (Hunter syndrome, severe). Ophthalmology 1985;92:1772-9. 3. Yoon MK, Chen RW, Hedges TR 3rd, et al. High-speed, ultrahigh resolution optical coherence tomography of the retina in Hunter syndrome. Ophthalmic Surg Lasers Imaging 2007;38:423-8.
Conflict of Interest
4. Chen TC, Cense B, Pierce MC, et al. Spectral domain optical coherence tomography: ultra-high speed, ultra-high
No potential conflict of interest relevant to this article was reported.
resolution ophthalmic imaging. Arch Ophthalmol 2005; 123:1715-20. 5. Bunt-Milam AH, Saari JC, Klock IB, Garwin GG. Zonulae adherentes pore size in the external limiting membrane of
References
the rabbit retina. Invest Ophthalmol Vis Sci 1985;26:137780.
1. Ashworth JL, Biswas S, Wraith E, Lloyd IC. Mucopolysaccharidoses and the eye. Surv Ophthalmol 2006;51:1-17.
Korean J Ophthalmol 2016;30(2):153-155 http://dx.doi.org/10.3341/kjo.2016.30.2.153
Macular Edema after Gabapentin Dear Editor, Gabapentin is an anticonvulsant and has been used to manage neuropathic pain. It was originally developed as an antiepileptic agent; however, it is now recommended as a drug of choice for the treatment of neuropathic pain. There is strong evidence that gabapentin is also effective in diabetic neuropathy and postherpetic neuralgia [1]. To the best of our knowledge, macular edema after use of gabapentin has not been reported to date. Therefore, we report a case of macular edema after gabapentin. A 71-year-old man presented with a 1 day history of visual disturbance and metamorphosis in both eyes. The patient had taken oral gabapentin (Neurontin; Pfizer, New York, NY, USA) and oral methylprednisolone (Methylon; Alvogen, Seoul, Korea) for 8 days for treatment of postherpetic neuralgia. He had no other significant medical history, except hypertension controlled by oral medication. Best-corrected visual acuity (Snellen) was 0.4 (right eye) and 0.2 (left eye), and the intraocular pressure was 9
mmHg (right eye), 11 mmHg (left eye), as determined by non-contact tonometry. Both eyes had moderate cataract. Ophthalmic examination of the anterior segments revealed no other abnormal findings. Dilated fundus examination and spectral domain optical coherence tomography revealed macular edema and serous retinal detachment of macula in both eyes (Fig. 1A-1D). Fluorescence angiography revealed fluorescein dye pooling on the macula and multiple leakages in both eyes (Fig. 1E and 1F). The patient was advised to discontinue gabapentin, and the use of the drug was stopped. Four weeks after the initial visit, best corrected visual acuity improved to 0.9 (both eye). Fundus exam and spectral domain optical coherence tomography revealed markedly improved macular edema and serous detachment in both eyes (Fig. 1G-1J). Gabapentin is an amino acid initially designed as a cyclic gamma-aminobutyric acid analogue with action as a gamma-aminobutyric acid agonist [2]. It also acts on different brain receptors by an as-yet unknown mechanism. Common adverse effects of gabapentin include dizziness, fatigue, drowsiness, sexual dysfunction, weight gain, and peripheral edema [3]. Uncommonly, gabapentin causes blurred vision and diplopia [4]. Steinhoff et al. [5] reported
153
