Nationwide Cross-sectional Study of Association between Pterygium and Alkaline Phosphatase in a Population from Korea

PURPOSE: We determined whether elevated serum alkaline phosphatase (ALP) was related to prevalence, location, type, length, and recurrence of pterygium in a population from the Republic of Korea.METHODS: A nationwide cross-sectional dataset, the Korean National Health and Nutrition Examination Survey (2008–2011), was used in this study. All participants were > 30 years of age and underwent the ALP test and ophthalmic evaluation (n = 22,359). One-way analysis of variance, the chi-square test, and Fisher's exact test were used to compare characteristics and outcomes among participants. Multivariable logistic regression was used to examine the possible associations between serum ALP levels and various types of pterygium. Data were adjusted for known risk factors for development of pterygium and ALP elevation (age, sex, residence, sunlight exposure, drinking, smoking, hypertension, diabetes, BMI, AST, ALT, vitamin D, and HDL).RESULTS: The overall prevalence of pterygium was 8.1%, and participants with pterygium had higher levels of serum ALP (p < 0.001). Participants with higher serum ALP had a significantly higher prevalence of all types of pterygium than those in the lower serum ALP quartiles. After adjusting for potential confounding factors, multivariate logistic regression analysis revealed that ALP was associated with the prevalence of pterygium (odds ratio [OR], 1.001; p = 0.038). Trend analysis between the OR and ALP quartiles revealed a linear trend in overall prevalence and in the intermediate type of pterygium. Subgroup analysis revealed a stronger correlation in participants > 50 years of age. One-way analysis of variance revealed an association between the size of pterygium and serum ALP quartile levels. Serum ALP was not associated with recurrence of pterygium.CONCLUSIONS: Increased serum ALP was associated with the prevalence and size of pterygium.

Endophthalmitis after Cataract Surgery in Korea: A Nationwide Study Evaluating Incidence and Risk Factors in a Korean Population

PURPOSE: To assess the nationwide rate of acute postoperative endophthalmitis (APE) after cataract extraction in Korea and to evaluate potential risk factors thereof. MATERIALS AND METHODS: Nationwide insurance claims data from July 2014 to June 2017 were reviewed. All patients with phacoemulsification or extracapsular/intracapsular cataract extraction were included. Exclusion criteria were combined glaucoma surgery or total vitrectomy or when the patient had a history of intraocular foreign body. RESULTS: In total, 1505103 cases (982203 patients) were included. APE developed in 953 cases (938 patients) with an overall incidence of 0.063%. After adjusting for possible confounding factors, male sex [odds ratio (OR) 1.42; 95% confidence interval (CI) 1.25–1.61; p<0.001], primary clinical setting, operations performed in non-major cities, usage of sutures (OR 2.82; 95% CI 2.13–3.74; p<0.001), anterior vitrectomy (OR 8.71; 95% CI 6.71–11.32; p<0.001), aphakic cataract surgery (OR 1.52; 95% CI 1.03–2.22; p=0.033), hypertension (OR 1.40; 95% CI 1.18–1.66; p<0.001), diabetes (OR 1.59; 95% CI 1.31–1.93; p<0.001), and chronic renal failure (OR 1.28; 95% CI 1.01–1.62; p=0.039) were found to be related to APE development. CONCLUSION: The incidence of APE after cataract extraction was consistent with reports from other studies. Additional research is needed to determine the relationship of newly found risk factors, such as hypertension, primary clinical setting, chronic renal failure, and usage of suturing, with APE development.

A Longitudinal Change of Spherical Equivalent in Anisometropic Children

PURPOSE: To demonstrate longitudinal refractive changes of anisometropia children. METHODS: This retrospective study included patients (or children) with anisometropia ≥ 1 diopters (D) for 5 years who visited our hospital between January 2013 and December 2014 with patients having annual refraction test data from 5-years-old to 10-years-old. RESULTS: A total of 37 children satisfied the inclusion criteria. Twenty-one children had hyperopic anisometropia and 16 children had myopic anisometropia. All hyperopic anisometropia and 12 myopic anisometropia children who had unilateral amblyopia were treated with occlusion therapy. The mean anisometropia at 5 years of age was 3.02 D and in the 37 children, the final degree of anisometropia was not significantly different between the 5-year-old and 10-year-old patients. In the high anisometropia and low anisometropia groups and in the myopia and hyperopia groups, the final degree of anisometropia was not significantly different at 5 years of age versus 10 years of age. CONCLUSIONS: In patients with anisometropia, spherical equivalent values did not show a significant difference when comparing 5-year-old versus 10-year-old patients and changes in the spherical equivalent values of eyes from both groups progressed to the same degree even if there was anisometropia in myopic and hyperopic patients.

Clinical Characteristics of Exodeviated Patients with Accomodative Esotropia and Hyperopia without Strabismus

PURPOSE: To evaluate the clinical characteristics of exodeviated patients with accomodative esotropia and orthophoric hyperopia. METHODS: We conducted a retrospective chart review of patients with accommodative esotropia and hyperopia who later developed exotropia and visited the Department of Ophthalmology of Wonju Severance Christian Hospital from January 1, 1997 to December 31, 2013. RESULTS: The study included 13 patients with a mean age of 4.1 years at initial referral. At the initial visit, nine patients (69.2%) had accommodative esotropia with a median of 25.5 PD esotropia at near gaze. Among the esotropic patients, four patients (44.4%) had unilateral amblyopia and five patients (55.6%) had bilateral amblyopia. The spherical equivalent was +6.09 D in the amblyopic eye and +5.63 D in the dominant eye. In the cases of bilateral amblyopia, the spherical equivalent was +5.875 D. Spontaneous consecutive exotropia developed at a mean age of 8.63 years (average follow-up of 56.38 months). Mean exodeviation was 10.33 PD. Among the four patients (30.8%) who were orthophoric at their initial visit, two patients (50%) had unilateral amblyopia and two (50%) had bilateral amblyopia. The spherical equivalents of the amblyopic eye and the dominant eye were +5.63 D and +3.13 D, respectively. In cases of bilateral amblyopia, a mean spherical equivalent of +5.50 D was observed. The mean age when exodeviation occurred was 10.75 years, which was 64 months after the initial visit. The average exodeviation was 6.5 PD. CONCLUSIONS: When treating accommodative esotropia and hyperopia, long-term observation is necessary since exodeviation could develop. Exotropia was successfully managed with spectacle correction. Further studies are needed for possible surgical intervention.

Eye Fixation in Patients with Dissociated Vertical Diviation

PURPOSE: To clinically determine the proportion of people with a fixed dissociating eye in patients with dissociated vertical deviation (DVD). METHODS: Medical records of 86 patients diagnosed with DVD in our department of ophthalmology from 2001 to November 2011 were retrospectively analyzed. RESULTS: Of the 71 patients, 25 (35.21%) showed a higher degree of dissociation in the fixating eye, 26 (36.62%) had higher dissociation in the non-fixating eye; 20 of 25 patients with a higher level of dissociation in the fixating eye and 22 of 26 patients with a higher level of dissociation in the non-fixating eye received surgical correction for DVD, such as superior rectus muscle recession or inferior oblique muscle anterior transposition. CONCLUSIONS: In DVD, the proportion of patients showing a higher level of dissociation in the fixating eye was significant. Patients with DVD require thorough evaluation; measurement of the level of dissociation and determination of the fixating eye is beneficial for management and surgical intervention.

Acute-Onset Vertical Strabismus in Adults

PURPOSE: To define the clinical characteristics of acute vertical strabismus in adults strabismus without known ocular and cranial external factors. METHODS: We performed a retrospective study of 72 adult patients who developed acute vertical strabismus without known ocular and cranial external factors such as trauma or operation and were followed up for at least 6 months. RESULTS: Undetermined cause (n = 41, 57%) was the most common etiology of acute vertical strabismus, followed by fourth cranial nerve palsy (n = 15, 20.8%), myasthenia gravis (n = 7, 9.7%), third cranial nerve palsy (n = 6, 8.3%), brain tumor (n = 2, 2.7%), and carotid-cavernous fistula (n = 1, 1.3%). The average vertical deviation at primary position was 7.2 prism diopter at initial visit. Thirty-eight (62.3%) patients recovered to orthophoria and 13 (21.3%) patients showed decreased level of diplopia. The average recovery period was 2.9 months. Ten cases remained as strabismus and 5 underwent surgery upon patient's request. CONCLUSIONS: Unknown cause was the most common diagonosis of adult acute vertical strabismus without known ocular and cranial external factors. In the present study, 62.3% of patients recovered to orthophoria and 83.6% recovered without surgical procedures.

Surgical Outcome of Vertical Rectus Muscle Recession in Hypertropia

PURPOSE: To determine the extent of vertical rectus muscle correction in hypertropia showing good prognosis. METHODS: A retrospective study was performed with a total of 16 patients who underwent superior or inferior rectus muscle recession surgery with a follow-up of more than 6 months. Vertical muscle recession of 1 mm per 2.5 to 3.0 prism diopters was performed according to the surgeon's discretion. RESULTS: At 1 week after surgical correction, undercorrection, orthophoria, and overcorrection was observed in 4, 7 and 5 cases, respectively. At the final examination, ocular deviation was decreased in the undercorrected cases and maintained orthophoric except in 1 case where only a small amount of deviation recurred. However, in the cases of postoperative overcorrectionn, ocular deviation increased; 2 cases required surgical correction for consecutive hypertropia. CONCLUSIONS: When performing vertical rectus muscle recession in primary hypertropia, the amount of correction for orthophoria or undercorrection should be determined.

The Effects of Stress on Intraocular Pressure and Lacrimal Secretion

PURPOSE: To evaluate the effects of psychosocial stress on intraocular pressure and lacrimal secretion. METHODS: Twenty normal adult volunteers (40 eyes) who had no history of systemic or ocular disease such as dry eye syndrome or glaucoma were recruited from clinical research participants. Heart rate, intraocular pressure and lacrimal secretion were measured after the Trier Social Stress Test (TSST) which induces psychosocial stress. The same measurements were taken 1 week later and the recorded measurements were considered as the control group. RESULTS: Heart rate was elevated significantly after the TSST, indicating psychosocial stress was induced by the TSST. Compared to stress resolution status, intraocular pressure and lacrimal secretion were increased after the TSST (p = 0.027, p = 0.011). Elevation of intraocular pressure and lacrimal secretion was statistically significant in males (p = 0.031, p = 0.007), but not significant in females (p = 0.336, p = 0.554). CONCLUSIONS: Psychosocial stress can increase intraocular pressure and lacrimal secretion.

Postoperative Exotropic Drift: Comparison of Surgical Methods Combined with Lateral Rectus Muscle Recession in Exotropia

PURPOSE: To assess the difference in the change of postoperative ocular alignment in intermittent exotropia corrected by horizontal muscle transposition or inferior oblique muscle recession together with lateral rectus muscle recession. METHODS: A total of 110 patients with intermittent exotropia with a follow-up period of more than 6 months after lateral rectus muscle recession were enrolled in the present study. The patients who received lateral rectus muscle recession only were classified as group 1, patients who received both lateral rectus muscle recession and horizontal muscle vertical transposition in both eyes were classified as group 2, and patients who underwent lateral rectus muscle and inferior oblique muscle recession were classified as group 3. The differences in postoperative ocular alignment among the patient groups were compared. RESULTS: Among the 3 groups, group 2 demonstrated the smallest amount of esotropic deviation in mean postoperative ocular alignment measured 1 day and 1 month after surgery. There was no significant difference among the groups in the mean postoperative ocular alignment and mean amount of exotropic drift at 6 months. The difference in the amount of postoperative exotropic drift 1 year after surgery among the 3 groups was statistically significant. The largest amount of postoperative exotropic drift was observed in group 1. CONCLUSIONS: In correcting intermittent exotropia, the largest amount of postoperative exotropic drift was observed in patients who received only lateral rectus muscle recession. By contrast, the smallest amount of postoperative exotropic drift was observed in patients who received lateral rectus muscle recession with vertical transposition of the horizontal muscle.

The effects of rocuronium and vecuronium on the increase in intraocular pressure associated with tracheal intubation

BACKGROUND: During ophthalmologic surgery, various intravenous anesthetic induction agents are used to prevent an intraocular pressure (IOP) increase. This study was designed to compare the effects of vecuronium and rocuronium on IOP in patients who were intubated. METHODS: Thirty-two patients undergoing elective strabismus surgery, aged 4 to 12 years, were randomized to receive rocuronium 0.6 mg/kg (Group 1, n = 16), or vecuronium 1.0 mg/kg (Group 2, n = 16).IOP, mean arterial pressure (MAP), and heart rate (HR) were measured at the following time points: prior to induction (B); after the administration of the induction agents; before intubation (T0); and at 1, 3 and 5 mins after intubation (T1, T3 and T5). RESULTS: The IOP after T0 in Group 1 was significantly lower than B (P < 0.05) in Group 2.The IOP at T1 in the Group 1 and 2 was not different from B, respectively.The IOP, MAP, and HR at T1 in the Groups 1 and 2 were significantly higher than at T0 (P < 0.05).No significant differences were observed between the groups in term of IOP. CONCLUSIONS: We concluded that vecuronium and rocuronium are both useful as muscle relaxants for use in general anesthesia in ophthalmologic surgery, because both agents caused similar decreases in intraocular pressure.

Refractive Change Caused Silicone Oil Adhesion to the Intraocular Lens Following Nd:YAG Posterior Capsulotomy

A 32-year-old female who had undergone the silicone oil removal procedure presented with visual disturbance in her left eye. Several months previous, she had cataract surgery in a private clinic, and a month later she had a Nd:YAG laser procedure for posterior capsulotomy. The slit-lamp examination revealed silicone oil droplets that had adhered to the intraocular lens where the posterior capsulotomy was performed. She had experienced high myopia as a manifestation of the resulting refractive changes. We replaced the previous intraocular lens with a new acrylic intraocular lens with resulting improvement to her vision. Here we report the case of a female patient with a history of silicone oil removal surgery where the resulting silicone bubbles had not been removed thoroughly and remained in the vitreous cavity. These bubbles subsequently adhered to the intraocular lens following YAG laser posterior capsulotomy, resulting in refractive changes. We recommend that implanting a silicone intraocular lens in anyone with a history of the silicone oil removal procedure or who has a possible history of silicone oil use should be avoided.

Vertical Rectus Muscles Transposition in Large Exotropia with Medial Rectus Muscle Transection Following Endoscopic Sinus Surgery

PURPOSE: To evaluate the effect of transposition procedures on the vertical rectus muscle (VRM) in the patients who underwent a medial rectus muscle (MR) transection after endoscopic sinus surgery (ESS). METHODS: In 4 patients with exotropia (XT) and a lack of adduction after ESS, orbital CT or MRI revealed a complete transection of the midportion of the MR. Full-tendon VRM transposition was performed within 3 months after injury (early surgery) in 2 patients with 40delta XT. Two patients with 70delta and 85delta XT underwent an X-type augmented Hummelsheim procedure, which involved pulling each half-tendon and crossing it through the undersurface of the severed MR to the other end of the MR insertion, concurrently with an ipsilateral lateral rectus (LR) recession 11 months and 36 months after ESS, respectively. The adduction deficits were divided into -1 through to -8. The patients were followed up for more than than 1.5 years. RESULTS: Postoperatively, 3 patients showed orthophoria and no diplopia in the primary position. The adduction deficits improved to -3.5 or -4. One patient who underwent an X-type augmented Hummelsheim procedure showed a residual XT of 25delta. CONCLUSIONS: VRM transposition is effective in correcting a large XT secondary to a MR transection after ESS. When a longstanding large-angle XT with severe contracture of the ipsilateral LR and massive scarring of the adjacent tissues is present, the X-type augmented Hummelsheim procedure coupled with an ipsilateral LR recession had an augmenting effect.

The Comparision of Outcomes Between Lateral Rectus Muscles Re-recession and Medial Rectus Muscles Resection in Recurrent Exotropia

PURPOSE: To compare the surgical outcomes between bilateral lateral rectus muscles (BLR) re-recession and bilateral medial rectus muscles (BMR) resection in recurrent exotropia. METHODS: The medical records of patients with recurrent exotropia who underwent surgery for intermittent exotropia during the 6 years from January 2001 to December 2006 and followed up for more than 6 months were reviewed retrospectively. RESULTS: In group A, BLR recessions was performed at the first surgery and BLR re-recession was performed at the second surgery. In group B, BLR recession was performed at the first surgery and BMR resection at the second surgery. Success rates at the last follow-up after the second operation were 81.9% in Group A and 83.3% in Group B, showing no statical difference between the two groups. In group A, no significant underaction of the BLR was noted. Success rates were not statistically different between the 2 mm re-recessed subgroup and 3 mm re-recessed subgroup. CONCLUSIONS: The results support the notion that BLR re-recession successfully corrects recurrent exotropia without producing significant limitation of abduction.

The Clinical Course of Consecutive Esotropia after Surgical Correction

PURPOSE: To investigate the clinical course in patients who underwent surgical correction of consecutive esotropia. METHODS: The medical records of 13 patients who underwent surgical correction of consecutive esotropia were reviewed retrospectively. The authors investigated the deviation and surgical method at the time of exotropia surgery. During the follow up period, the authors also studied incidence of amblyopia development, the effect of occlusion therapy, surgical methods for consecutive esotropia, and postoperative change of deviation. RESULTS: The average exodeviation was 27.1 prism diopter (PD). Bilateral lateral rectus muscle recession was performed in all patients. In all patients, alternate occlusion was tried from 2 weeks after development of consecutive esotropia. However, there was no effect on 7 patients. None of the patients developed amblyopia. Surgery for consecutive esotropia was performed on the average 15.3 months after exotropia surgery. The average esodeviation was 21.1PD. Medial rectus muscle recession was performed in 10 patients and lateral rectus muscle advancement in 3 patients. The average deviation of the subject group immediately after surgery was 1.2PD esodeviation, 0.9PD esodeviation one month after surgery, 2.4PD exodeviation 6 months after surgery, and 4.7PD exodeviation at the last follow up, and it showed a tendency to progress to exodeviation as the follow up period increased. Ten patients (76.9%) showed deviation within 8PD at the last follow up. CONCLUSIONS: The success rate of surgical correction for consecutive esotropia was a favorable outcome. But, careful decisions of the surgical method and amount is needed because the conversion of exodeviation during long-term follow-up is possible.

Characteristics and Outcome in Horizontal Strabismus Combined with Unilateral Superior Oblique Palsy

PURPOSE: To review the clinical characteristics and treatment outcomes in horizontal strabismus combined with unilateral superior oblique palsy (SOP). METHODS: A retrospective review of medical records was conducted in 21 patients with unilateral SOP treated between January 2001 and December 2005. Patients had more than 6 months of follow-up at the Department of Ophthalmology, Wonju College of Medicine. RESULTS: Among 21 patients (11 male, 10 female) with unilateral SOP, 57.1% of patients had horizontal strabismus. The mean vertical deviation was 12.56+/-3.81 (8~24) PD. All patients with horizontal strabismus had exotropia and the mean deviation was 10.57+/-4.58 (6~20) PD. A standard 10mm inferior oblique (IO) recession was performed uniformly at the paretic eye in all patients. In 7 of the patients (58.3%, exotropia greater than or equal to 10PD), horizontal rectus muscle recession was performed simultaneously. In these 7 cases, vertical and horizontal deviation less than or equal to 4PD was achieved (one patient with 10PD remaining hypertropia excluded). In 5 cases with exodeviation less than 10PD, isolated IO recession without horizontal rectus recession on the ipsilateral side achieved orthophoria in the primary position. In 9 cases of isolated SOP, all patients showed orthophoria in the primary position. CONCLUSIONS: This study demonstrates horizontal strabismus is combined with unilateral SOP in a high percentage of patients. Additionally, in all cases, all the incidents of horizontal deviation was involved exotropia. A standard 10 mm recession of the IO in combination with horizontal rectus recession is an effective surgical technique. It has an especially high success rate in patients with unilateral SOP (< or =14PD vertical deviation) with exodeviation greater than 10PD. In patients with exodeviation less than 10PD, an isolated IO recession is sufficiently effective.

Conjunctival Expansion Using a Subtenon's Silicone Implant in New Zealand White Rabbits

PURPOSE: In the field of ophthalmology, the conjunctival autograft is a useful therapeutic material in many cases, but the small size of the autograft is a disadvantage. Therefore, we evaluated the feasibility of taking an expanded sample of conjunctival tissue using a subtenon's silicone implant. MATERIALS AND METHODS: We included a total of nine rabbits; eight rabbits were operative cases, and one was a control. A portion of conjunctival tissue from the control rabbit, which did not undergo surgery, was dissected and examined to determine whether it was histologically different from the experimental group. The surgical procedure was performed on eight rabbits via a subtenon's insertion of a silicone sponge in the left superior-temporal portion; after surgery, we dropped antibiotics into the eyes. We sacrificed a pair of rabbits every three days (on days 3, 6, 9, and 12) after surgery, removed the expanded conjunctival tissues with the silicone sponge implants, and measured their sizes. RESULTS: The mean size of the expanded conjunctival tissues was 194.4mm(2). On the third day, we were able to harvest a 223.56mm(2) section of conjunctival tissue, which was the most expanded sample of tissue in the study. On the twelfth day, we removed a 160.38mm(2) section of conjunctival tissue, which was the least expanded sample of tissue. Statistically, there were no significant differences in the mean dimensions of the expanded conjunctival tissues for each time period. Microscopic examinations showed no histological differences between the expanded conjunctival tissues and the normal conjunctival tissues. CONCLUSION: The results reveal that this procedure is a useful method to expand the conjunctiva for grafting and transplantation.

A Case of Photic Retinal Injury Associated with Exposure to Plasma Arc Welding

PURPOSE: To report of photic retinopathy induced by plasma arc welding, and the OCT (optical coherence tomography) results of damaged retinal lesions. METHODS: We describe a case report of a 37-year-old male, working in the steel industry, who presented with central scotoma in both eyes. RESULTS: On his first visit, one day after performing plasma arc welding with protective gear at work, his best corrected vision was 0.7 for both eyes. Ophthalmic examination of the fundus showed a round yellow lesion with an approximate size of 300 micrometers superonasal to the fovea of both eyes. On his next visit, one month later, his vision had recovered to 1.0, his symptoms had improved, and the ophthalmoscopic examination of the fundus revealed that the round yellow spots had disappeared from both eyes. CONCLUSIONS: To our knowledge, this is the first report of photic retinopathy induced by plasma arc welding, and the OCT (optical coherence tomography) results of damaged retinal lesions have not previously been reported. For these reasons, we report this case.

Classification of Ptosis in Korea

PURPOSE: To classify blepharoptosis in Korean patients, investigate the type of surgery used, and to compare the results with the data from Western countries. METHODS: A total of 913 patients (1147 eyes) who underwent surgery for blepharoptosis from 1991 to 2003 were classified as either being congenital or acquired blepharoptosis, and then further subclassified into myogenic, aponeurotic, mechanical, or neurogenic ptosis according to Freuh's mechanistic classification. The type of surgery for each type of blepharoptosis was investigated. RESULTS: Of the 913 patients, 695 (76.1%) were congenital type, and 218 (23.9%) were acquired type. Freuh's mechanistic classification by type was 84.7% myogenic type, 10.5% aponeurotic, 3.4% neurogenic, and 1.6% mechanical. By order of frequency, the type of surgery used was 60% frontalis suspension, 26.4% levator resection, 12.2% aponeurosis repair, and 1.4% conjunctivomullerectomy. CONCLUSIONS: Congenital type was more common than acquired type. The proportion of congenital type was higher than the results reported from Western countries, but lower than those of previous Korean studies. This is probably due to the increased number of adults undergoing surgery for blepharoptosis compared to the past, and is a reflection of influence of socio-economic levels.

The Characteristics of Acute Concomitant Esotropia of Adulthood

PURPOSE: To identify the characteristics of adult patients who develop acute concomitant esotropia during adulthood. METHODS: Using a retrospective noncomparative method, this study evaluated the medical charts of 10 adults who were diagnosed with acute onset esotropia between January 2003 and May 2005. All patients presented the symptoms of estotropia when they were older than age 18. All patients in the study group had no previous ocular history, no cause of interruption of fusion, no history of systemic disease or head trauma, and no abnormal findings on neurologic examination. RESULTS: The average follow-up period was 10.8 months (range, 5 ~ 17 months). The mean age was 44.7 years (range, 18 ~ 62 years). The average refractive error was -1.43 diopter (range, -5.50 ~ +0.50 diopter). An operation was performed in one case. The prism diopter decreased according to follow-up in other patients. CONCLUSIONS: There are characteristics of acute onset esotropia of adulthood that differentiate it from existing esotropia. Almost all patients were myopic, showed nearly the same prism diopter between near and far vision, and deviation improved with follow-up.

Characteristics of Nicotinic Receptor Expressed in Human Retinoblastoma

PURPOSE: To identify the characteristics and physiological function of the nicotinic receptor expressed in human retinoblastoma cells. METHODS: We measured possible nicotinic signaling in WERI-Rb-1 cells using the Ca2+ imaging technique and the patch clamp method. RESULTS: 1) Nicotine-induced [Ca2+]i rise arose entirely through Ca2+ influx, which was completely abolished by hexamethonium (100 micro M). 2) Nicotine also induced remarkable depolarization from -56.6 +/- 3.7 mV to -29.6 +/- 3.6 mV (n=4) under current clamp mode, but it failed to directly activate the T-type Ca2+ channel expressed in retinoblastoma cells. CONCLUSIONS: Nicotinic activation can increase the intracellular calcium level through calcium influx in the undifferentiated retinoblastoma cells, which may play important roles in cell proliferation, differentiation, and cell death.