Associated factors for visibility and width of retrobulbar subarachnoid space on swept-source optical coherence tomography in high myopia.

Subarachnoid space (SAS) around optic nerve can be visible with swept-source optical coherence tomography (SS-OCT). However, the relevant factors for its visibility and width have not been reported. In this prospective study, 193 eyes with high myopia were evaluated by SS-OCT. The relationship between age, gender, axial length, optic disc area, parapapillary atrophy (PPA) area, peripapillary choroidal thickness with the visibility and width of SAS were assessed. The results showed that SAS was observed in 125 (64.8%) and not observed in 68 (35.2%) eyes. Visibility of SAS is associated with long axial length, high myopia, thin choroid, large PPA and large optic disc areas. Among these associations, PPA area was the only independent factor (b = 0.177, p < 0.001). The width of SAS was associated with thin choroid, long axial length, large optic disc area and large PPA area. Multivariant analysis showed that optic disc area and PPA area were independent factors for the width of SAS (b = 30.8, p = 0.016 and 16.2, p < 0.001 respectively). These results suggested that SAS was extended into the peripapillary region possibly due to extension of posterior sclera in high myopia.

Development of clinical visual physiology in China during the past fifty years.

In the past 50 years, China has experienced a valuable development stage of clinical visual physiology and made substantial progresses in the aspects. It not only contributes to ophthalmology development, but also cultivates the precious visual physiology scientist and researcher groups in China and will advance Chinese ophthalmology toward a glorious future.

[Retinal symmetry of multifocal visual evoked potential in both eyes of normal subjects].

PURPOSE: To analyze the retinal symmetry of multifocal visual evoked potential (mfVEP) in both eyes of normal subjects. METHODS: The monocular mfVEP in both eyes of 36 normal subjects (72 eyes) were tested with VERIS Science 4.0. The stimulus was the pattern reversal dart array consisted of 60 sectors, each included 16 black-white reverse patterns. The visual stimulation was controlled by a binary pseudo-random m-sequence and subtended 25 degrees of retinal region. RESULTS: The mfVEP patterns between left and right eyes of each subject were similar, and P1 latency and amplitude in correspondent visual field quadrants between left and right eyes had no significant difference(P>0.05). The latency of superotemporal visual field quadrant in right eyes was shorter than that of superonasal visual field quadrant in left eyes, and the amplitude of superonasal visual field quadrant in right eyes was longer than that of superotemporal visual field quadrant in left eyes(P<0.05). The P1 latency and amplitude among four visual field quadrants of each eye had significant difference(P<0.05). The P1 latency between the superonasal visual field quadrant and inferotemporal visual field quadrant or between the superonasal visual field quadrant and inferonasal quadrant visual field had significant differences in right or left eyes(P<0.05). CONCLUSION: The mfVEP of normal subjects exists retinal symmetry.

Angiographic leakage of polypoidal choroidal vasculopathy on indocyanine angiography.

BACKGROUND: There is no detailed report about the angiographic leakage of polypoidal choroidal vasculopathy (PCV) lesions on indocyanine green (ICG) angiography. This study aimed to investigate the angiographic leakage of polypoidal lesions in PCV on ICG angiography. METHODS: One hundred and forty-four eyes of 137 patients diagnosed as PCV were prospectively observed. Fundus examination, fluorescein angiography, and ICG angiography were performed. Leakage of polypoidal lesions and clinical features were recorded according to the angiograms. RESULTS: In all 144 eyes, 110 eyes showed angiographic leakage (leakage group) on ICG angiography and three subtypes of leakage group were noted, which were polypoidal dilations leakage (47 eyes, 42.7%), branching vascular networks leakage (14 eyes, 12.7%) and leakage of both (49 eyes, 44.5%). The other 34 eyes showed regression of polypoidal lesions (regression group). In leakage group, the rates of pigment epithelial detachment (PED), best corrected visual acuity (BCVA) < 0.1 and old subretinal hemorrhages were 56.4% (62 eyes), 19.1% (21 eyes), and 4.6% (5 eyes) respectively, compared with 8.8% (3 eyes), 50% (17 eyes) and 38.2% (13 eyes) of regression group (P < 0.001). The history of regression group was significantly longer (P < 0.001). CONCLUSIONS: Angiographic leakage and regression can be observed in PCV lesions. Leakage of both polypoidal dilations and branching vascular networks is the most common subtype in leakage group. PCV in leakage group is more likely to be related to PED, better BCVA and shorter history, while PCV regression group tends to relevant to old subretinal hemorrhage, worse BCVA and longer history. This may reflect that the former is active or in the early course while the later is resting or in the late phase of PCV.

OCT and muti-focal ERG findings in spontaneous closure of bilateral traumatic macular holes.

PURPOSE: To report the spontaneous closure of bilateral traumatic macular holes in a young patient, followed up with optical coherence tomography (OCT), muti-focal electroretinogram (mfERG), and Humphrey visual field examination. METHODS: A 25-year-old male who suffered from bilateral blunt trauma to the eyes and developed traumatic macular holes was followed with ophthalmic examination, OCT, mfERG, and Humphrey visual field examination. RESULTS: The OCT results revealed spontaneous closure in both eyes 2 weeks after trauma, and the macular holes remained closed in the 7 months of follow-up. Visual acuity improved to 0.7 in right and 0.9 in left eye finally. Visual field examination and mfERG results improved slightly compared with the initial tests. However, there still were central scotomas in both eyes, especially in right eye at the end of follow-up, and the peaks of the retinal response density had not recovered in the macular area of the mfERG topography. CONCLUSIONS: Spontaneous closure of unilateral traumatic macular hole is not uncommon, but there is no report of spontaneous closure of bilateral traumatic macular holes as yet. Since the traumatic macular holes may close spontaneously, traumatic macular holes may be observed for a period of follow-up.

The photopic negative response of flash ERG in nonproliferative diabetic retinopathy.

PURPOSE: To test how the PhNR of the flash ERG is affected in human nonproliferative diabetic retinopathy (NPDR). METHODS: The PhNR was elicited with red stimuli (5 cd s/m(2) with 4-min duration) and blue background (10 cd/m(2)). Standard Ganzfeld flash ERGs were recorded according to the ISCEV standard for the clinical electroretinogram (2004). A total of 81 diabetic patients with different severity levels of NPDR were examined. Forty-three age-matched normal controls were also studied. RESULTS: The amplitude of PhNR decreased significantly as DR progressed, while the implicit time was prolonged. Amplitudes of the PhNR in the control group, no DR, mild NPDR, moderate NPDR, and severe NPDR were 78.1 +/- 15.1 microV, 69.0 +/- 17.8 microV, 64.5 +/- 13.2 microV, 45.9 +/- 9.0 microV, and 33.7 +/- 10.8 muV respectively, and the implicit times of PhNR were 71.5 +/- 5.0, 72.0 +/- 6.2, 73.6 +/- 5.0, 75.7 +/- 6.1, and 82.9 +/- 7.8 min respectively. Compared to the control group, the reduction of PhNR amplitude in all diabetic groups was statistically significant. However, except for the OPs, the percent reduction of the amplitude of standard ERG waves was far less than that of the PhNR. The percent decrease in amplitude of the PhNR and summation OPs was not significantly different in any diabetic group. However, the reduction of the amplitude of summation OPs (and other standard ERG waves) was statistically significant only in moderate and severe NPDR groups. CONCLUSIONS: PhNR is a sensitive indicator of the function of inner retina in diabetic patients. There is a potential role for the PhNR in assessing inner retinal damage and evaluating the effect of treatment in NPDR.

Functional and clinical findings in 3 female siblings with crystalline retinopathy.

PURPOSE: To present functional and clinical findings in three female siblings with crystalline retinopathy. METHODS: Functional and clinical examinations, including full-field and multi-focal electroretinograms (ERG), visual field, dark adaptation and fundus fluorescein angiography (FFA) were performed in three female siblings of a nonconsanguineous Chinese family, who exhibited characteristic retinal crystalline flecks of Bietti crystalline retinopathy. RESULTS: Ophthalmological examination revealed similar findings in the first and second daughter of the family. Best-corrected visual acuity was hand movement and finger counting respectively and funduscopic examination showed RPE clumping and relatively fewer yellow-white deposits in the posterior pole and mid-peripheral retina. FFA revealed massive RPE and choriocapillaris destruction. Ganzfeld ERG was undetectable or reduced markedly and multifocal ERG showed all responses were markedly depressed. Ophthalmological examination showed relative preservation of retinal function in the third daughter of the family (the proband). Best-corrected visual acuity was 0.5 in the right eye and 0.4 in the left eye. Funduscopic examination showed numerous crystal deposits scattered throughout the posterior pole. Dark adaptation revealed rod thresholds elevated dramatically and visual field examination demonstrated paracentral scotomas in both eyes. Full-field ERG was decreased slightly and multifocal ERG showed the central responses were markedly depressed. CONCLUSION: The present study describes typical crystalline retinopathy affecting three female siblings in a family.

Polypoidal choroidal vasculopathy coexisting with exudative age-related macular degeneration.

PURPOSE: To report two cases that had polypoidal choroidal vasculopathy (PCV) coexisting with choroidal neovascularization (CNV) of exudative age-related macular degeneration (AMD). METHODS: Both of the patients underwent color photographs, fluorescein and indocyanine green (ICG) angiography. RESULTS: On fundus examination, a grayish lesion in the foveal area, reddish-orange lesions and hemorrhagic retinal pigment epithelial detachments (PED) in the inferotemporal vascular arch were disclosed in the left eye of a patient, and macular scarring was observed in the fellow eye. ICG angiography revealed a typical branching vascular network and polyp-like aneurysmal dilations at terminals of branches in the inferotemporal vascular arcade and a well-demarcated hyperfluorescent area of CNV in the fovea in the left eye, and staining of macular scarring was present in the fellow eye. On fundus examination of the right eye of the other patient a gray-yellow lesion at the fovea, reddish-orange lesions in the extramacula were noted, and diffuse drusens were present in the fellow eye. ICG angiography revealed scattered polyp-like aneurysmal dilations without identifiable continuous branching vascular network in the extramacula, and a well-demarcated hyperfluorescence area of CNV in the fovea. CONCLUSIONS: PCV can coexist with exudative AMD in some patients and the polypoidal lesions may less involve in the fovea than CNV. Evidence of AMD are present meanwhile in the fellow eyes these patients.

[The electroretinogram of infants with nystagmus].

PURPOSE: To find the characteristics and clinical application of electroretinogram (ERG) in infants with nystagmus. METHOD: Forty-six cases (92 eyes) of infants with nystagmus (aged 2-72 months old) were tested with Neuropack MEB-2200K system according to the ERG standard of ISCEV. RESULTS: Five kinds of ERG responses of all subjects but one could be recorded. The abnormal rates of the rod ERG, standard mixture ERG, oscillatory potentials, single-flash cone ERG and 30 Hz flicker response were 65%, 86%, 61%, 77% and 62% respectively. The ERG abnormalities were evaluated from the 5 responses. The rod ERG decreased in 5 eyes. The rod-cone ERG decreased in 11 eyes. The cone ERG decreased in 14 eyes. The cone-rod ERG decreased in 23 eyes. The standard mixture ERG decreased in 8 eyes. The ERG was unrecordable in 8 eyes. The mild, middle, and severe decreases of rod and cone ERG appeared in 5 eyes respectively. The normal ERG was only recorded in 8 eyes. CONCLUSION: Abnormal rate of ERG is 91% in infants with nystagmus. The retina abnormality may pay an important role in the pathogenesis of nystagmus.

Choroidal folds in Vogt-Koyanagi-Harada disease.

PURPOSE: To analyze choroidal folds in Vogt-Koyanagi-Harada (VKH) disease by fluorescein angiography (FA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT). DESIGN: Retrospective, consecutive case series. METHODS: Records of 95 patients diagnosed with VKH disease from October 2001 to July 2006 were reviewed. All patients underwent FA, 17 patients underwent ICGA, and 20 underwent OCT. RESULTS: Of the 95 patients, 11 (12.0%) had choroidal folds and showed 10 to 15 hypofluorescent bands radiating from the optic disk that were similar to the large retinal vessels in shape and number on FA. On ICGA, the choroidal folds showed hyperfluorescence at the late stage. OCT showed clear folds but the number of folds was larger than on FA and ICGA. CONCLUSIONS: Choroidal folds are not uncommon in VKH disease. FA, ICGA, and OCT can help to identify their pathogenesis.

Subtype lesions of neovascular age-related macular degeneration in Chinese patients.

PURPOSE: To identify the subtype frequency and clinical features of neovascular age-related macular degeneration (AMD) in Chinese patients. METHODS: From January 2003 to August 2006, we investigated prospectively 155 newly diagnosed patients with presumed neovascular AMD. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed in both eyes of all patients. Subtype frequency and clinical features were recorded according to their angiograms. RESULTS: Three subtypes of lesion were noted, which were polypoidal choroidal vasculopathy (PCV), retinal angiomatous proliferation (RAP) and mixed lesions. Of the 155 patients, 105 (67.7%) had choroidal neovascularization (CNV) of the typical type seen in AMD, 38 (24.5%) had PCV and seven (4.5%) had RAP. In five (3.2%) additional cases, mixed lesions were noted. In 38 cases (47 eyes) with PCV, the rates of subfoveal, juxtafoveal and extrafoveal lesion were respectively 29.8% (14 eyes), 8.5% (four eyes), and 61.7% (29 eyes), compared with 75.6%, 14.6% and 9.8% for CNV lesion (P < 0.01). The percentage of subfoveal lesion in PCV group was significantly lower than that in the CNV group (P < 0.01). The location of the RAP lesion was subfoveal in two (28.6%) eyes, juxtafoveal in three (42.9%) eyes and extrafoveal in two (28.6%) eyes. The five eyes with mixed lesions were all PCV coexisting with CNV at the same eye, and in all of the five cases, CNV was subfoveal while PCV was extrafoveal. CONCLUSIONS: In this hospital-based study, PCV accounts for 24.5% of neovascular AMD and is the most common subtype, RAP is less frequent (4.5%), and mixed lesions are much less common in Chinese patients. PCV is least likely to involve the fovea in neovascular AMD.

Indocyanine green angiographic findings of Dalen-Fuchs nodules in Vogt-Koyanagi-Harada disease.

PURPOSE: The purpose of this study was to analyze indocyanine green (ICG) angiographic findings of Dalen-Fuchs nodules in Vogt-Koyanagi-Harada (VKH) disease. METHODS: ICG angiograms of 15 patients (30 eyes) with Dalen-Fuchs nodules in VKH disease of between 2 months and 5 years after the initial diagnosis were retrospectively studied. Findings of ICG angiography were compared with features of fundus fluorescein angiography (FFA). RESULTS: Dalen-Fuchs nodules were easily found in the inferior (30 eyes, 100%) and temporal periphery (22 eyes, 73%) and showed two kinds of fluorescence in ICG angiography. In ten patients (20 eyes), the nodules showed small round hypofluorescent dark dots in the whole process of angiography, and the dark dots were larger in size than the nodules in FFA. Disease course in these patients was relatively long-between 1 year and 5 years. On clinical examination, the nodules were atrophic, and hyperpigmentation was found around them. In another five patients (ten eyes), parts of the nodules showed small hyperfluorescent dots in the early phase, but they were faint in the intermediate phase and became large, hypofluorescent dark dots in the late phase. Disease course in these patients was between 2 and 8 months. The nodules were bright yellow, fresh, and much larger than those in the first kind of ICG fluorescence. CONCLUSIONS: Dalen-Fuchs nodules in VKH are mostly present in the inferior and temporal periphery. The two kinds of fluorescence of Dalen-Fuchs in ICG angiography may reflect obliteration of choriocapillaris under the nodules and different quantities of lipofuscin in the nodules at different time points of the disease.

[Multifocal visual evoked potential in retinitis pigmentosa and its comparison with visual field].

PURPOSE: To investigate the characteristics of the multifocal visual evoked potential (mfVEP) and to evaluate the potential of mfVEP as a way of objective perimetry in retinitis pigmentosa (RP). METHODS: The mfVEPs were obtained by using VERIS 4.9 visual evoked response imaging system for 12 RP patients (19 eyes) and 15 normal control subjects (30 eyes). The stimulative field consisted of 60 sectors in a dartboard configuration, the visual angle of one side was 26 degrees. The amplitude sums of P1 wave of the first slice of the second order kernel from patients with RP were compared with values from control subjects. The central 30 degrees visual fields were obtained in the RP patients. Correlation between sensitivity sums of visual field and amplitude sums of P1 wave was performed in the same area. RESULTS: The amplitude sums of P1 wave decreased significantly at all rings in RP group compared with those of normal control group (P < 0.05). Except for inferior ring 1 and inferior ring 2, there was correlation between sensitivity sums of visual field and amplitude sums of P1 wave at the other rings (P < 0.05). CONCLUSION: There was a certain correlation between visual field and mfVEP. The mfVEP can be a method to evaluate visual function objectively in RP.

[Microperimetry evaluation in central serous chorioretinopathy].

PURPOSE: To evaluate the macular fixation and retinal sensitivity of Central Serous Chorioretinopathy (CSC) with MP-1 microperimeter (Nidek Technologies, Vigonza, Italy). METHODS: Nineteen consecutive patients (total 21 eyes; 5 eyes of chronic stage, 6 eyes of acute stage, 5 eyes of recovering stage, and 5 eyes of recurring stage; 10 eyes of visual acuity no less than 1.0, 6 eyes of 0.6-0.9 and 5 eyes of no better than 0.5)and 20 normal control subjects (20 eyes) were evaluated. MP-1 microperimeter was used to quantify macular sensitivity and fixation. RESULTS: The difference of fixation between the CSC and the control eyes is not significant (P > 0.05). The retinal sensitivity in CSC declined significantly (P < 0.05) and varied significantly in different groups(P < 0.05). CONCLUSION: MP-1 microperimeter can quantifiably evaluate the fixation and macular sensitivity of CSC. Moreover, it improves the functional evaluation in CSC.

[The study of the classification on polypoidal choroidal vasculopathy].

PURPOSE: To establish and explore the criteria of the classification on polypoidal choroidal vasculopathy (PCV). METHODS: The 42 patients (48 eyes) with PCV were classified according to the location, staining or not in late indocyanine green angiography (ICGA), with or without branching vascular network, and the extent of hemorrhagic or exudative. RESULTS: According to the location, staining or not in late ICGA, with or without branching vascular network, and the extent of hemorrhagic or exudative, the PCV were classified as macular (30 eyes, 62.5%), arcade (6 eyes, 12.5%), peripapillary (3 eyes, 6.3%), midperiphery and Combination PCV (9 eyes, 18.8%); active (34 eyes, 70.8%) and inactive PCV (14 eyes, 19.2%); typical (36 eyes, 75.0%) and atypical PCV (12 eyes, 25.0%); hemorrhagic (35 eyes, 72.9%) and exudative PCV (13 eyes, 27.1%), respectively. The classification on location of the polypoidal lesions and with or without branching vascular network of the lesions were the first suggested. CONCLUSIONS: The classification of PCV is beneficial for describing the clinical manifestations and for predicting the prognosis and for guiding the treatment of the disease.

The photopic negative response of the flash electroretinogram in retinal vein occlusion.

The photopic negative response (PhNR) has recently been shown to be severely affected in central retinal artery occlusion (CRAO), despite relative preservation of the cone b-wave compared to that in the healthy unaffected fellow eye. The aim of this study was to test how the PhNR of the flash electroretinogram (ERG) is affected in human retinal vein occlusion. PhNR was elicited with red stimuli (1 cd s/m2, 5 cd s/m2, and 7 cd s/m2 with 4 ms duration) and blue background (10 cd/m2). Standard Ganzfeld flash ERG was produced according to the ISCEV standard for the clinical electroretinogram (2004). Sixteen patients with central retinal vein occlusion (CRVO), 14 patients with branch retinal vein occlusion (BRVO), and 16 controls were analyzed. The amplitude of the PhNRs was significantly smaller in the CRVO and BRVO eyes than those in the unaffected fellow or control eyes (p = 0.000). There was a significantly greater reduction of PhNR amplitudes than that of other waves including the OPs, rod b-wave, combined a-wave and b-wave, cone a-wave and b-wave, and 30 Hz flicker ERG. Thus, PhNR amplitude in retinal vein occlusion is severely affected. There is a potential role for PhNR in assessing inner retinal damage and evaluating the effect of treatment.

Unilateral retinitis pigmentosa with amblyopia in the fellow eye.

PURPOSE: The purpose was to report a case of unilateral retinitis pigmentosa with amblyopia in the other eye. METHODS: Eight years ago, a 36-year-old woman complained of peripheral visual field loss in her left eye when she covered her right eye. Complete ophthalmological examinations including fundus photography and fluorescein angiography, full-field electroretinography, dark adaptation, and microperimetry were performed. RESULTS: Best-corrected visual acuity of the patient was 0.2 with +2.5 diopters in her right eye and 0.3 with +1.5 diopters in her left eye. Fundus examination did not reveal any abnormalities in the right eye, but narrow retinal vessels, optic disc pallor, and peripheral retinal pigment clumping was found in the left eye. The full-field electroretinography was normal in the right eye, but rod response, cone response, and combined response were non-recordable, and 30-Hz response was very small in the left eye. Dark adaptation thresholds were normal in the right eye, but were dramatically elevated in the left eye. Microperimetry was normal in the right eye, but the visual field was reduced to a 2x5 degrees central field in the left eye. CONCLUSION: Unilateral retinitis pigmentosa with amblyopia in the other eye is a rare condition. The patient presented here had a case of unilateral retinitis pigmentosa with the other eye with ametropic amblyopia. It is necessary to perform functional and morphological ophthalmological examinations to confirm the diagnosis.

Early subfoveal choroidal neovascularization secondary to an accidental stage laser injury.

PURPOSE: To report a case of early subfoveal choroidal neovascularization secondary to an accidental stage laser injury. METHODS: A 22-year-old female technician complained of visual loss and an immovable shadow in her right central vision after being irradiated accidentally by a laser light beam with a wavelength of 532 nm while aligning a stage laser light. She underwent a full ophthalmologic examination 5 days later; including visual acuity, color fundus photography and fluorescein angiography. Eight months later these examinations were repeated, accompanied by optical coherence tomography. RESULTS: Best-corrected visual acuity in her right eye was 0.08 at 5 days after the injury and hand motion 8 months later; acuity remained at 1.2 in the left throughout follow-up. A small grayish-yellow lesion with exudation was present at the foveal area in the right eye 5 days after the injury. Eight months later the lesion had enlarged and hemorrhage had appeared. A classic choroidal neovascularization was detected in the subfovea on both fluorescein angiography and optical coherence tomography. Another 4 months later the visual acuity had increased to 0.01. Funduscopic examination revealed the lesion unchanged and the hemorrhage diminished. CONCLUSIONS: Stage laser light with a wavelength of 532 nm may cause early subfoveal choroidal neovascularization when used inappropriately.

Experimental study on relationship between retinal vein occlusion and loss of vitreous gel mass.

PURPOSE: To explore the relationship between retinal vein occlusion (RVO) and loss of vitreous gel mass. METHODS: An experimental RVO was induced by a photodynamic method in one eye (experimental eye) of 17 chinchilla rabbits. The contralateral eye was used as an untreated control. The changes in vitreous gel mass and liquefaction were investigated one month later. Changes in molecular properties of type II collagen in vitreous were analyzed by western immunoblot analysis. RESULTS: An RVO was successfully induced in 13 of 17 chinchilla rabbits (76.5%), which caused loss of vitreous gel mass and loss of elasticity, accompanied by release of a water-like liquid from the gel. The alpha chains of type II collagen were crosslinked together to form high molecular weight components of beta and gamma, which weakened the stability of collagen net structure. CONCLUSIONS: Loss of vitreous gel mass occurred in RVO eyes. The crosslinks of vitreous collagen may damage the stability of collagen structure, and promote loss of vitreous gel mass.

[Reversal effect of haloperidol on doxorubicin resistance and chloride channel inhibition in erythroleukemic cell K562/Dox].

OBJECTIVE: To investigate the reversal effect of haloperidol (Hal) on doxorubicin (Dox) resistance and its inhibition effect on P-glycoprotein and swelling-activated chloride channel in Dox-resistant erythro-leukemic cell line K562/Dox. METHODS: Tumor cell proliferation was measured by LDH assay. mRNA expressions of P-glycoprotein (MDR1), glutathione S-transferase Pi (GSTpi) and MDR-associated protein (MRP) of K562/Dox treated with Hal were assayed by RT-PCR. Chloride-sensitive dye MQAE was loaded into K562/Dox cells and the intracellular fluorescence intensity was measured to evaluate the effect of Hal on chloride channel in swelling-activated K562/Dox cells. Coulter counter ZM and Channelyzer 256 were used to measure cell volume regulation. RESULTS: Hal significantly reversed Dox resistance in K562/Dox cells after 12.50, 6.25 and 3.12 micromol/L Hal treatment, the chemosensitivity to Dox increased by 8.61, 4.35 and 2.25 times respectively. After treatment with Hal 12.50 micromol/L, MDR1 and MRP mRNA expression were gradually down-regulated in a time-dependent manner on d1-d3, reducing to 76.3% and 64.6% of the control level on d3 (P < 0.05), while GSTpi mRNA expression decreased by 66.1% (P < 0.05) on d1-d2, and began to recover on d3. The swelling-activated chloride channel and cell regulatory volume decreased (RVD) in K562/Dox cells were also inhibited by Hal. Under hypotonic challenge the cellular fluorescence intensity which represented chloride concentration declined by (34.46 +/- 5.91)%. After adding 6.25 micromol/L and 18.75 micromol/L Hal, the hypotonic challenge only caused decrease in fluorescence intensity by (24.43 +/- 3.25)% and (16.63 +/- 4.98)% (P < 0.01). RVD in hypotonic condition was (84.95 +/- 5.69)%. RVD under hypotonic condition with 6.25 micromol/L and 18.75 micromol/L Hal were (51.12 +/- 6.01)% and (39.51 +/- 4.79)% respectively (P < 0.01). CONCLUSION: A nontoxic concentration of haloperidol can significantly reverse drug resistance through a multi-pathway effect, including down-regulating mRNA expressions of MDR, GSTpi and MRP, inhibition of swelling-activated chloride channel and RVD in K562/Dox cells.