Four cases of orbital hyperdensity identified by postmortem computed tomography.

Postmortem computed tomography (PMCT) has become a common examination method in the field of forensic medicine. Head computed tomography provides information of the orbit and eyes, and forensic pathologists may come across abnormal intraocular findings of cadavers upon PMCT. Here, we present four cases in which we identified orbital hyperdensity by PMCT. The first case showed calcified senile scleral plaques (CSSP), whereas the second case showed foreign bodies in the palpebral fissure, which resembled CSSP upon PMCT. The third case showed signs of silicone oil injection in the eye, while the fourth case showed bilateral phthisis bulbi. In the first case, the presence of CSSP was found to be helpful for age estimation, whereas the findings of cases 3 and 4 aided in the personal identification of the subjects. As demonstrated by these cases, intraocular PMCT findings may provide highly useful information, and correct interpretation of the intraocular PMCT findings by forensic pathologists is hence crucial.

Frontal suspension for congenital ptosis using an expanded polytetrafluoroethylene (Gore-Tex(®)) sheet: one-year follow-up.

BACKGROUND: The frontalis suspension technique is the surgical method of choice in patients with ptosis and a levator function of 4 mm or less. Several types of materials have been used, including Gore-Tex(®), which has been used successfully as a frontalis sling material since 1986. Recently, a Gore-Tex sheet (wider than a sling or strip) suspension was reported. This paper reports the results of 27 eyes from 20 patients with congenital ptosis treated using the frontalis suspension technique with the newly developed Gore-Tex Most Versatile Patch (MVP) sheet. METHODS: All patients underwent surgery between April 2007 and September 2011 and were followed up for at least one year. The average follow-up duration was 18 months, with a range of 12-36 months. The average patient age was 45 (5-85) years, and the group included 11 males and nine females. Thirteen cases demonstrated ptosis in one eye, and seven cases involved both eyes. The patients were divided by age into a younger group and an older group. All ptosis procedures were performed using the Gore-Tex MVP sheet. The implant was normally 7 mm wide for adults and 5 mm wide for children. The implantation method was the same as that used for the sheet shape fascia. RESULTS: In all patients, satisfactory functional results were observed at the 6-month follow-up examination. Eyelid opening heights were also obtained. The average marginal reflex distance (MRD) was -0.5 mm preoperatively, which improved to +1.9 mm after surgery. After one year, average MRD was +1.6 mm. MRD attenuation was more frequent in the younger group. There were no cases requiring redo surgery and only one case of exposure.

Combination of a modified Hotz procedure with the Jones procedure decreases the recurrence of involutional entropion.

PURPOSE: Involutional entropion is a common condition in Asian countries, including Japan. One cause of involutional entropion is weakening of the capsulopalpebral fascia (CPF). The aged, thin, membranous nature of the CPF limits the results of correction by the original Jones procedure (CPF tightening) alone, so we added the modified Hotz procedure to the entropion repair. We then compared the recurrence rates and operation times in corrections performed with and without this additional procedure. CASES: From April 2010 to December 2011, one surgeon performed lower-lid surgery using the Jones procedure with the addition of the modified Hotz procedure. Fifteen patients (a total of 21 eyes) underwent this combined procedure. Previously, the same surgeon performed the Jones procedure alone for eight patients (a total of nine eyes). RESULTS: The average age of the two groups was 76.4 years, with an age range of 66-85 years. All cases reported acceptable ciliary orientation at the end of the surgery. However, patients who underwent the Jones procedure alone (nine eyes total) reported three cases of recurrence after at least 6 months of follow-up. Patients who underwent the combined procedure reported two complications: one recurrence and one ectropion. The recurrence rate was 5%. The Jones procedure using eyelid pinch required an average of 22.6 minutes to complete; the combined method required 33.4 minutes to complete. CONCLUSION: The combined method resulted in a significantly higher success rate than the Jones procedure alone (P < 0.05). The 5% failure rate of the combined method was found to be superior to the 30% recurrence rate of the Jones procedure. As a result, the Hotz procedure enhanced the results of the entropion correction and required only 10 additional minutes of surgery. We now perform this combined procedure for all cases.

Fish-tail resection for treating congenital entropion in Asians.

PREFACE: The Asian race has a high prevalence of congenital entropion. It was reported that over 20% of Japanese children have congenital entropion at the age of 1 year. One of the structural causes of this condition is the development of epiblepharon, which attaches the lower eyelid to the upper eyelid, and is also common among Asians. However, designing a procedure for modifying an epicanthus flap is relatively difficult, and epicanthoplasty is not a popular procedure in Japan. In the present study, we developed an easy method of designing the surgery, and we describe both the surgical procedure and the outcome. CASES: Between January 2010 and August 2011, one surgeon performed surgery to correct congenital entropion in 28 patients. We analyzed this series of 28 cases retrospectively. The patients consisted of 17 females and eleven males with an average age of 7.6 years. Ten patients with a thick epicanthal fold required epicanthoplasties in addition to lower lid procedures, and 18 patients with a thin epicanthal fold required only lower lid procedures. SURGICAL METHOD: On the epicanthus, a small, triangular "fish-tail" flap that was 2 mm wide was designed and was located adjacent to a "fish-body" marking on the subciliary lower eyelid. After fish-tail resection, the residual medial edge was sutured to the corner of the epicanthus. A C-shaped epicanthus was changed into an L-shape by means of this procedure. RESULT: The fish-tail resection diminished the tension of the orbicularis in the superior direction. After a minimum of 6 months, the shape of the medial canthus remained L-shaped, and the cilia had stable orientations. CONCLUSION: This plasty is easy to design in conjunction with a Hotz procedure, and it is an effective means of correcting Asian congenital entropion. Recognizing the shape of a congenital entropion that is accompanied by epiblepharon is important for its radical treatment.

[Epicanthoplasty simultaneous with epiblepharoplasty in cases of epiblepharon with epicanthus].

INTRODUCTION: Postoperative recurrence is common following surgery in patients with epiblepharon and co-existing epicanthal folds. We report the results of using combined epicanthoplasty and modified Hotz's procedure techniques aimed at correcting the structural anomalies and improving surgical out-come. METHODS: We performed combined epicanthoplasty and modified Hotz's procedure procedures on 5 patients (10 eyelids) between May 2007 and October 2008. The surgical procedures involved redraping the medial canthal skin folds using Uchida's method in 4 patients and Z-plasty in 1 patient. RESULT: Epiblepharon was resolved following surgery, and the symptoms improved immediately. The preoperative pathognomonic appearance with the nasal conjunctiva almost hidden by the epicanthus changed, and the nasal conjunctiva became visible postoperatively. There were no signs of recurrence at postoperative follow up (range, 6-20 months, mean 9.4 months). CONCLUSION: Combined epicanthoplasty and modified Hotz's procedure produced good postoperative results, with no signs of recurrence. However, lack of experience in skin flap design and inappropriate surgical manipulation could lead to unsightly scar formation and adverse cosmetic results. We therefore recommend that epicanthoplasty be decided by experts in oculoplastic surgery.

Evaluation of phosphenes elicited by extraocular stimulation in normals and by suprachoroidal-transretinal stimulation in patients with retinitis pigmentosa.

BACKGROUND: To determine the efficient parameters to evoke electrical phosphenes is essential for the development of a retinal prosthesis. We studied the efficient parameters in normal subjects and investigated if suprachoroidal-transretinal stimulation (STS) is effective in patients with advanced retinitis pigmentosa (RP) using these efficient parameters. METHODS: The amplitude of pupillary reflex (PR) evoked by transcorneal electrical stimulation (TcES) was determined at different frequencies in eight normal subjects. The relationship between localized phosphenes elicited by transscleral electrical stimulation (TsES) and the pulse parameters was also examined in six normal subjects. The phosphenes evoked by STS were examined in two patients with RP with bare light perception. Biphasic pulses (cathodic first, duration: 0.5 or 1.0 ms, frequency: 20 Hz) were applied through selected channel(s). The size and shape of the phosphenes perceived by the patients were recorded. RESULTS: The maximum PR was evoked by TcES with a frequency of 20 Hz. The brightest phosphene was elicited by TsES with a pulse train of more than 10 pulses, duration of 0.5-1.0 ms and a frequency of 20 to 50 Hz. In RP patients, localized phosphenes were elicited with a current of 0.3-0.5 mA (0.5 ms) in patient 1 and 0.4 mA (1.0 ms) in patient 2. Two isolated or dumbbell-shaped phosphenes were perceived when the stimulus was delivered through two adjacent channels. CONCLUSION: Biphasic pulse trains (> or =10 pulses) with a duration of 0.5-1.0 ms and a frequency of 20-50 Hz were efficient for evoking phosphenes by localized extraocular stimulation in normal subjects. With these parameters, STS is a feasible method to use with a retinal prosthesis even in advanced stages of RPs.

Threshold suprachoroidal-transretinal stimulation current resulting in retinal damage in rabbits.

The purpose of this study is to determine the threshold suprachoroidal-transretinal stimulation (STS) current that results in retinal damage in rabbits. Biphasic STS pulses (anodic first, frequency 20 Hz) were used to stimulate the retina of pigmented rabbits (n = 18) continuously for 1 h using a 100 microm diameter platinum wire electrode. The STS current that induced retinal damage after 1 h was determined by ophthalmoscopy or by fluorescein angiography (FA) independently. The effect of the pulse duration on the threshold current was investigated. Histological studies were performed after electrical stimulation experiments. The threshold for a safe current to the retina was 0.6 mA for a duration of 0.5 ms. The threshold for a safe charge increased approximately linearly with an increase of stimulus duration but the threshold for a safe current decreased logarithmically with an increase of duration. The threshold for a safe electrical energy remained almost constant for all durations. Histological examination showed severe retinal damage when the current exceeded the threshold, with more damage in the inner layers compared with the outer layers of the retina. The threshold for the safe current was higher than that reported for direct stimulation of neural tissues, suggesting that the STS method was safe and able to be used with a retinal prosthesis. Because the threshold for the safe charge was lower with shorter pulse durations, care should be taken using pulses of short durations.

Transretinal electrical stimulation by an intrascleral multichannel electrode array in rabbit eyes.

BACKGROUND: A new method of stimulating the retina electrically, called suprachoroidal transretinal stimulation (STS), was shown to be effective in eliciting electrically evoked cortical potentials (EEPs) in Royal College of Surgeons (RCS) rats. Before extending this technique to patients, it is important to determine its safety and feasibility in eliciting EEPs from medium-size animal (rabbits). The purpose of this study was to determine the safety and efficacy of the surgical procedures used to implant an multichannel electrode array into a scleral pocket, and to determine whether the implanted electrodes can stimulate the retina effectively. METHODS: These acute experiments were conducted on six rabbits. An array of eight gold microelectrodes, embedded in polyimide, was implanted into a scleral pocket over the visual streak area. The size of the microarray was 2 x 4 x 0.180 mm. The reference electrode was implanted into the vitreous. The electrode array and reference electrodes were connected to a stimulator to deliver monophasic current pulses. Cortical responses were recorded with a stainless steel electrode implanted into each rabbit's skull over the visual cortex. After the experiment, the eyes and electrodes were examined histologically. RESULTS: The surgical procedures for electrode implantation were accomplished without serious complications. EEPs were recorded after monophasic electrical pulse stimulation from each electrode. The mean threshold for EEPs was 55.0+/-10.0 microA with a 0.5-ms duration inward current pulse. The charge delivered at threshold was about 27.5 nC, and the charge density was about 56.0 microC/cm2. Histopathological examination of the retinal tissue around the area of stimulation did not show damage at the light microscope level with the electrical parameters used. CONCLUSIONS: Our technique for STS with an intrascleral microelectrode array is safe in rabbit eyes, and EEPs were elicited by current densities that did not induce tissue damage. These results suggest that STS via intrascleral multichannel electrodes is a feasible method for stimulating the retina.

Electrical stimulation with a needle-type electrode inserted into the optic nerve in rabbit eyes.

PURPOSE: To investigate whether electrical stimulation of the optic nerve can elicit an electrical evoked potential (EEP) in rabbits and to determine whether such stimulation is a useful approach for the placement of a visual prosthesis. METHODS: Two needle-type electrodes were inserted into the optic nerve using a transvitreal approach. For electrical stimulation, monophasic and biphasic pulses were used. By stimulating the optic nerve, the EEP was elicited. After evaluation of the EEP, a histological study was carried out. RESULTS: When electrical stimulation was applied, the EEP could be recorded. The threshold with monophasic and biphasic stimulation was 10 +/- 0 microA and 20 +/- 8.2 microA, respectively. Histological examination revealed no major complications, such as bleeding or degeneration, which might have resulted from the insertion of electrodes or the electrical stimulation. CONCLUSIONS: Electrical stimulation of the optic nerve can elicit an EEP, suggesting that this approach may be useful for a visual prosthesis system.

Transretinal electrical stimulation with a suprachoroidal multichannel electrode in rabbit eyes.

PURPOSE: Several approaches for placing an electrode device for visual prosthesis have been previously proposed. In this study, we investigated if transretinal stimulation from the suprachoroidal space can elicit an electrical evoked potential (EEP) in albino rabbits. METHODS: A flat electrode array (polyimide plate, platinum electrode) was developed and used for this study. After performing a scleral incision at 2-2.5 mm from the limbus and placing an anchoring suture, the array was inserted into the suprachoroidal space in the posterior portion of the eye by direct observation under a microscope. A platinum wire was implanted into the vitreous space as a reference electrode. For electrical stimulation, a biphasic pulse was used. When the electrode was stimulated, the EEP was recorded. RESULTS: When the electrical stimulation from the suprachoroidal space was applied, the EEP could be recorded with an epidural electrode, and the threshold was 66.0 +/- 32.1 micro A (420 micro C/cm(2)) [corrected]. placement of the array and the electrical stimulation. CONCLUSIONS: Transretinal electrical stimulation from the suprachoroidal space could elicit EEP, suggesting that this approach may be useful for a retinal prosthesis system.