Performance of Bandage Contact Lens in Patients Post-ocular Surgeries: A Systematic Literature Review.

ABSTRACT: This study systematically reviewed the performance of bandage contact lenses (BCL) such as lotrafilcon A, lotrafilcon B, senofilcon A, balafilcon A, and comfilcon A as postoperative treatment in different ocular surgeries. A systematic search of English and Chinese databases (from inception to December 2021) was conducted for studies reporting the efficacy of BCLs after ocular surgeries. Postoperative symptoms, corneal healing, and visual outcomes were studied. Overall, 38 studies were identified. Bandage contact lens was applied as a postoperative aid in corneal refractive, cataract, and vitrectomy surgeries. Most studies were on photorefractive keratectomy. Reduced postoperative symptoms were observed within 4 hr to 3 days, whereas re-epithelization of the cornea and healing was complete within 3 to 7 days after ocular surgeries except for vitrectomy. In a vitrectomy, greater comfort and improved corneal epithelium were observed on the seventh day after surgery. An improvement in dry eye symptoms was observed at 7 days with considerable benefits observed after 1 month of cataract surgery. These findings indicate that BCLs are effective for improving postoperative symptoms and facilitation of early visual rehabilitation with a wear time of 8 hr to 7 days depending on the type of ocular surgery.

Comparison of total corneal power measurements obtained with different devices after myopic keratorefractive surgery.

AIM: To analyze the differences, agreements, and correlation among total corneal power parameters generated by different instruments after myopic keratorefractive surgery. METHODS: The prospective cross-sectional study included patients who underwent myopic keratorefractive surgery and received measurements of corneal power 3mo after surgery. Automated keratometer was used for the measurement of simulated keratometry (SimK), swept-source optical coherence tomography (SS-OCT) based biometer for total keratometry (TK), anterior segment-OCT for real keratometry (RK), and Scheimpflug keratometer for the true net power (TNP), the total corneal refractive power (TCRP) and equivalent K-readings (EKR). The differences among these parameters were analyzed, and the agreements and correlation between SimK and other total corneal power parameters were investigated. RESULTS: A total of 70 eyes of 70 patients after myopic keratorefractive surgery were included. The evaluated corneal power parameters were as follows: SimK 38.32±1.93 D, TK 37.54±2.12 D, RK 36.64±2.09 D, TNP 36.56±1.97 D, TCRP 36.70±2.01 D, and EKR 37.55±2.00 D. Pairwise comparison showed that there were significant differences (P<0.001) among all parameters except for between TK and EKR, RK and TNP, RK and TCRP (P=1.000, 1.000, 1.000, respectively). The limits of agreement between SimK and TK, RK, TNP, TCPR, and EKR were 1.08, 1.08, 1.43, 1.48, and 1.73 D, respectively. All parameters showed good correlation with SimK, and the correlation coefficients were 0.995, 0.994, 0.983, 0.982, and 0.975. CONCLUSION: Among the corneal power parameters after myopic keratorefractive surgery, the value of SimK is the largest, followed by TK and EKR, with TCRP, RK, and TNP being the smallest. The differences among the parameters may be attributable to the different calculation principles. Correct understanding and evaluation of corneal power parameters can provide a theoretical basis for taking advantage of the total corneal power to improve the accuracy of intraocular lens calculation after keratorefractive surgery.

Comparison of clinical outcome of small-incision lenticule intrastromal keratoplasty and FS-LASIK for correction of moderate and high hyperopia.

AIM: To compare the clinical outcome of small-incision lenticule intrastromal keratoplasty (sLIKE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for correction of moderate and high hyperopia. METHODS: A case-controlled clinical study was performed. Twenty right eyes of 20 moderate and high hyperopia patients underwent sLIKE (sLIKE group) and 22 right eyes of 22 moderate and high hyperopia patients underwent FS-LASIK (FS-LASIK group) were enrolled in this study from October 2015 to October 2017. Visual acuity, refractive error, corneal thickness, and keratometry were compared between the groups before and 1y postoperatively. RESULTS: The postoperative uncorrected near visual acuity (UNVA) and uncorrected distance visual acuity (UDVA) were improved in the two groups. The UNVA reached J1 in 15 eyes (75.0%) in the sLIKE group and 5 eyes (22.7%) in the FS-LASIK group 1y after surgery (χ 2=11.476, P=0.001). The UDVA was equal or better than the preoperative CDVA in 16 eyes (80.0%) in the sLIKE group and 8 eyes (36.4%) in the FS-LASIK group, respectively (χ 2=8.145, P=0.004). No eyes lost any line of best-corrected visual acuity (BCVA) in either group. The amount of postoperative residual hyperopia in the sLIKE group was significantly less than in the FS-LASIK group (Z=-2.841, P=0.004). The postoperative keratometry and corneal thickness were significantly higher in the sLIKE group than in the FS-LASIK group (t=4.411, 10.279, P<0.001). The SRI and SAI of the sLIKE group were significantly higher than that in the FS-LASIK group. There was no statistically significant difference in mean decentration between the two groups. CONCLUSION: sLIKE has better visual and refractive outcome than FS-LASIK for correction of moderate and high hyperopia.

Adenovirus-mediated RNA interference against herpes simplex virus infection in vitro.

INTRODUCTION: Herpetic keratitis caused by the herpes simplex virus (HSV) is the most common form of ocular herpes that causes corneal blindness. Although treatments for herpes keratitis have improved in recent years. there is still considerable room for new treatments against viral infection that shows great promise. The aim of the study was to evaluate the effect of RNA interference on HSV Type 1 (HSV1) infection in vitro, first prophylactically then therapeutically. MATERIAL AND METHODS: The highly conserved glycoproteins D (gD) and E (gE) were chosen as targets for this study. Different small interfering RNA (siRNA) duplexes that target gD and gE were designed and chemically synthesized. The recombinant adenovirus type 5 was developed and used as the vehicle with which we delivered the siRNA into the Vero cells infected with the HSV1 KOS strain. Evaluation of the efficacy of siRNA-mediated inhibition was performed either before virus inoculation (prophylactically) or after virus inoculation at the first appearance of lesions (therapeutically). The expression of messenger RNA encoding gD and gE was detected using a real-time polymerase chain reaction (qPCR). We analyzed HSV replication in Vero cells, cytotoxicity of HSV, and cell viability. RESULTS: When used prophylactically, the siRNA-targeting gD and gE created a more marked decrease in viral titer than when used therapeutically. The transfection of cells with recombinant adenovirus containing the siRNA expression cassette was associated with very low cytotoxicity. CONCLUSIONS: Adenovirus-mediated siRNA-targeting gD and gE genes effectively inhibit the replication of the HSV in Vero cells. In addition, these findings indicate that the prophylactic use of siRNA is far more effective at inhibiting HSV replication than the therapeutic use.

Evaluation of preoperative dry eye in people undergoing corneal refractive surgery to correct myopia.

AIM: To investigate the incidence of preoperative dry eye and related factors in patients undergoing corneal refractive surgery to correct myopia. METHODS: A total of 141 patients with myopia who underwent corneal refractive surgery were surveyed by questionnaires, tear film break-up time (BUT) test, Schimer I test (SIt), corneal fluorescein staining (FL) test and diagnosed according to the currently recognized domestic diagnostic criteria for dry eye. Correlation analysis of factors such as age, gender, regular wearing of contact lens (CL), diopter (spherical equivalent), corneal thickness, and corneal curvature that may affect the onset of dry eye was carried out to clarify the main influencing factors. RESULTS: There were 64 patients (45.39%) diagnosed with dry eye. The male patients (20.31%) was significantly less than that of non-dry eye subjects (41.56%; χ 2=7.260, P=0.007); the proportion of patients with dry eye wearing CL (81.25%) was significantly higher than that of non-dry eye subjects (51.95%; χ 2=13.234, P<0.001); the median diopter level of dry eye patients was -6.59 (IQR: -8.87, -4.58) D, and the median diopter level of non-dry eye subjects was -5.69 (IQR: -7.15, -4.03) D. The diopter level of dry eye patients was significantly higher (Z=-2.086, P=0.019). However, the age, best corrected visual acuity, and intraocular pressure of dry eye patients were not statistically different from those of non-dry eye subjects (t=-0.257, -0.383 and 0.778, P=0.798, 0.702, and 0.438); the corneal thickness and corneal curvature (K1 and K2) were also not statistically different either (Z=-1.487, -1.036 and -1.707, P=0.137, 0.300, and 0.088). The research further analyzes the three significant factors in the single factor analysis (gender, CL wear, and diopter) in a multi-factor way: CL wear and diopter were the influencing factors of dry eye disease. Among them, CL wear increased the risk of dry eye by 2.934 times compared with no CL wear; for every 1 D increase in diopter, the risk of dry eye increased by 0.761 times. CONCLUSION: Preoperative dry eye is relatively common in patients who undergo corneal refractive surgery to correct myopia, especially in patients who have a history of CL wear and a high diopter level before surgery. Therefore, it is necessary to carry out preoperative screening and timely treatment of dry eye to obtain the best treatment outcome and postoperative satisfaction.

Comparison of correcting myopia and astigmatism with SMILE or FS-LASIK and postoperative higher-order aberrations.

AIM: To compare the effect of myopia and astigmatism correction and postoperative change in higher-order aberration as results of receiving small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). METHODS: A prospective and non-randomized controlled study was conducted. The subjects are divided into two groups according to different operations received: 229 eyes of 116 patients in the SMILE group and 168 eyes of 86 patients in the FS-LASIK group. All subjects were followed up for 3mo by monitoring their uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent, higher-order aberrations, and the preoperative and postoperative complications. RESULTS: At 1wk, 1, and 3mo post-surgery, 224 eyes (97.8%), 227 eyes (99.1%) and 229 eyes (100%) had UCVA≥20/20 in the SMILE group, while 165 eyes (98.2%), 167 eyes (99.4%) and 167 eyes (99.4%) had UCVA≥20/20 in the FS-LASIK group, respectively (χ 2=0.146, 2.135, and 1.124; all P>0.05). BCVA reduction was not observed in both groups at 1 and 3mo of post-surgery (χ 2=0.734 and 1.898, P>0.05). There was no statistically significant difference in the spherical equivalent between the two groups at 1 and 3mo post-surgery, though the percentage of the spherical equivalent within ±0.50 D at 3mo post-surgery was 98% in the SMILE group, which was higher than that of the FS-LASIK group (92%, χ 2=1.872, P>0.05). The root mean square (RMS) values of total high-order aberration, coma, and spherical aberration of the two groups increased significantly in the early postoperative period and decreased after 3mo, but the values were still higher than the preoperative levels (P<0.05); there was no significant difference between the two groups in the RMS values of total higher-order aberrations and specific higher-order aberrations (P>0.05). The incidence of complications in the SMILE group was lower than that in the FS-LASIK group (χ 2=14.52, P<0.05). CONCLUSION: SMILE and FS-LASIK can effectively treat myopia, significantly improve visual acuity, and increase the total high-order aberration, spherical aberration, and coma. The incidence of complications after SMILE is relatively low.

Comparison of corneal curvature parameters obtained from two different instruments-Pentacam and VX120.

AIM: To explore whether the same corneal curvature parameters and anterior chamber depth measured by Pentacam and VX120 have a good consistency and can replace each other. METHODS: This study enrolled 140 eyes of 70 patients ranging in age from 19 to 53y. All eyes underwent a comprehensive ophthalmologic examination including an anterior segment analysis with the VX120 system (Visionix-Luneau Technologies, Chartres, France) and Pentacam (Oculus Optikgerate GmbH) respectively. The comparison on corneal curvature parameters was done between Pentacam and VX120 using clustered signed rank test; the interclass correlation coefficients (ICC) with 95% confidence intervals (CI) was calculated for each parameter between Pentacam and VX120; the Bland-Altman plot of each parameter was supplemented. RESULTS: The anterior corneal curvature measured by VX120 was Ks: 44.00±1.78 D, KsAt: 89.45±22.18, Kf: 42.84±1.58 D, KfAt: 93.91±79.34; which measured by Pentacam was Ks: 43.80±1.82 D, KsAt: 91.17±21.40, Kf: 42.61±1.64 D, KfAt: 91.16±78.69. There was statistical difference between Pentacam and VX120 for anterior corneal curvature parameter (P<0.001). The posterior corneal curvature measured by VX120 was Ks: -6.42±1.23 D, KsAt: 91.00±23.45, Kf: -5.85±1.24 D, KfAt: 95.93±79.11; which measured by Pentacam was Ks: -6.44±0.32 D, KsAt: 92.24±11.75, Kf: -6.01±1.05 D, KfAt: 74.43±80.64. There was statistical difference between Pentacam and VX120 for posterior corneal curvature parameters (P<0.001). Anterior chamber depth (ACD) measured by Pentacam and VX120 was statistically different. Pentacam and VX120 achieved high consistency only on corneal anterior surface, including Ks and Kf. The ICCs were 0.96 (95%CI: 0.95, 0.97) and 0.95 (95%CI: 0.94, 0.97) respectively. For other corneal surface curvature parameters, all ICCs of between Pentacam and VX120 were below 0.87. Bland-Altman plots indicated of low consistency of corneal surface curvature parameters measured by Pentacam and VX120. CONCLUSION: The corneal curvature parameters and anterior chamber depth measured by Pentacam and VX120 were statistically different. Data measured by Pentacam and VX120 is not suggested to replace each other, mixing data measured by Pentacam and VX120 together is not suggested either.

Comparison of corneal flaps created by Wavelight FS200 and Intralase FS60 femtosecond lasers.

AIM: To assess and compare the morphology of corneal flaps created by the Wavelight FS200 and Intralase FS60 femtosecond lasers in laser in situ keratomileusis (LASIK). METHODS: Four hundred eyes of 200 patients were enrolled in this study and divided into Wavelight FS200 groups (200 eyes) and Intralase FS60 groups (200 eyes). Fourier-domain optical coherence tomography (RTVue OCT) was used to measure the corneal flap thickness of 36 specified measurements on each flap one week after surgery. Results were used to analyze the regularity, uniformity and accuracy of the two types of LASIK flaps. RESULTS: The mean thickness of corneal flap and central flap was 105.71±4.72 µm and 105.39±4.50 µm in Wavelight FS200 group and 109.78±11.42 µm and 109.15 ±11.59 µm in Intralase FS60 group, respectively. The flaps made with the Wavelight FS200 femtosecond laser were thinner than those created by the Intralase FS60 femtosecond laser (P=0.000). Corneal flaps in the 2 groups were uniform and regular, showing an almost planar configuration. But the Wavelight FS200 group has more predictability and uniformity of flap creation. The mean deviation between achieved and attempted flap thickness was smaller in the Wavelight FS200 group than that in the Intralase FS60 group, which were 5.18±3.71 µm and 8.68±7.42 µm respectively. The deviation of more than 20 µm was 0.2% measurements in Wavelight FS200 group and 8.29% measurements in Intralase FS60 group. CONCLUSION: The morphologies of flaps created by Wavelight FS200 are more uniform and thinner than those created by Intralase FS60.

Comparison of Ziemer FEMTO LDV "Classic" and "Crystal Line" femtosecond laser flap quality by Fourier-domain optical coherence tomography.

AIM: To compare the regularity and accuracy of laser in situ keratomileusis (LASIK) flaps created by the Ziemer FEMTO LDV "Classic" (Ziemer "Classic") and Ziemer FEMTO LDV Crystal Line femtosecond laser (Ziemer Crystal Line). METHODS: Fourier-domain optical coherence tomography (RTVue OCT) was used to measure the morphology of 200 LASIK flaps of 100 consecutive patients created with the Ziemer Classic (100 flaps) or the Ziemer Crystal Line (100 flaps) at one week postoperatively. Flap thickness was evaluated at 36 specified measurement points on each flap. For all procedures with both lasers, the nominal flap thickness was 110µm. RESULTS: The mean flap thickness of the Ziemer Crystal Line group (102.49±2.68µm) was thinner than that of the Ziemer Classic group (107.65±5.09µm) (P<0.01). Average thickness of all flaps was uniform within 4µm at all measurement points. The flaps in the Ziemer Crystal Line group were more regular than those in the Ziemer Classic group when measured from the center to the periphery. The maximum deviation from the nominal 110µm of 36 measurements was 8µm in the Ziemer Classic group, while in the Ziemer Crystal Line group it was 9µm. Within the 3 600 measurements on the 100 eyes, differences greater than 20µm were observed 0.14% in the Ziemer Classic group, and 0.04% in the Ziemer Crystal Line group. CONCLUSION: The flaps created with the Ziemer FEMTO LDV Crystal Line femtosecond laser are more uniform and thinner than those created by the Ziemer FEMTO LDV Classic femtosecond laser.

Comparison of the flaps made by femtosecond laser and automated keratomes for sub-bowman keratomileusis.

BACKGROUND: Thin-flap laser in situ keratomileusis (LASIK) is the new trend of refractive error correction surgery, the formation of corneal flap is crucial for a success of LASIK surgery. This study aimed to assess and compare the variations of LASIK flap created by the IntraLase femtosecond laser, Moria One Use-Plus SBK and Moria M2 Single-Use 90 µm-head microkeratome using Anterior segment optical coherence tomography (Visante OCT). METHODS: One hundred and sixty-one eyes of 81 consecutive patients were enrolled in this prospective study and randomly divided into three groups depending on the flap creation method: flap creation with the the IntraLase femtosecond laser (IntraLase group, 59 eyes), flap creation with the Moria One Use-Plus SBK (SBK group, 44 eyes), and flap creation with the Moria M2 Single-Use 90 µm-head microkeratome (M2SU90 group, 58 eyes). The nominal flap thickness was 110 µm for all patients and for the three devices. One month after surgery, Visante OCT was used to measure the flap thickness at 20 locations on each cornea and the results were assessed for uniformity, regularity, and accuracy. RESULTS: At 1 month after surgery, the mean central flap thickness was (111 ± 3) µm in the IntraLase group, (114 ± 8) µm in the SBK group, and (118 ± 13) µm in the M2SU90 group respectively. The flaps in the IntraLase group and the SBK group were more regular, showing an almost planar configuration, than the meniscus-shaped flaps in the M2SU90 group. The maximum deviation from the intended flap thickness (110 µm) was 6 µm in the IntraLase group, 10 µm in the SBK group, and 20 µm in the M2SU90 group respectively. A difference greater than 20 µm was observed in 0.42% of measurements in the IntraLase group; 2.95% of the measurements in the SBK group and 21.12% of measurements in the M2SU90 group. CONCLUSIONS: The flaps created by the IntraLase femtosecond laser and Moria One Use-Plus SBK are more uniform; more regular, and more accurate than those created by the Moria M2 Single-Use 90 µm-head microkeratome. The first two methods can make precise flaps for Sub-Bowman Keratomileusis.

HCO(3)(-)-dependent soluble adenylyl cyclase activates cystic fibrosis transmembrane conductance regulator in corneal endothelium.

cAMP-dependent activation of the cystic fibrosis transmembrane conductance regulator (CFTR) regulates fluid transport in many tissues. Secretion by the corneal endothelium is stimulated by cAMP and dependent on HCO(3)(-). We asked whether HCO(3)(-) can secondarily increase CFTR permeability in bovine corneal endothelial cells (BCEC) by activating soluble adenylyl cyclase (sAC). Immunofluorescence suggests that sAC is distributed throughout the cytoplasm. HCO(3)(-) (40 mM) increased cAMP concentration 42% in the presence of 50 microM rolipram (a phosphodiesterase 4 inhibitor), and a standard HCO(3)(-) Ringer solution (28.5 mM) increased apical Cl(-) permeability by 78% relative to HCO(3)(-)-free solution. The HCO(3)(-)-dependent increase in Cl(-) permeability was reduced 60% by 20 mM NaHSO(3) (a weak agonist of sAC). NaHSO(3) alone increased apical Cl(-) permeability by only 13%. The HCO(3)(-)-dependent increase in Cl(-) permeability was reduced 57% in the presence of 50 microM Rp-adenosine 3',5'-cyclic monophosphorothioate, and 86% by 50 microM 5-nitro-2-(3-phenylpropyl-amino)benzoic acid but unaffected by 200 microM apical H(2)DIDS. CFTR phosphorylation was increased 23, 150, and 32% by 20 mM HSO(3)(-), 28.5 mM HCO(3)(-), and 28.5 mM HCO(3)(-) + 20 mM HSO(3)(-), respectively. Activation of apical Cl(-) permeability by 5 microM genistein was increased synergistically by HCO(3)(-) over that due to genistein and HCO(3)(-) alone. We conclude that HCO(3)(-)-stimulated sAC is a form of autocrine signaling that contributes to baseline cAMP production, thereby affecting baseline CFTR activity in BCEC. This form of autocrine signaling may be important in tissues that express sAC and exhibit robust HCO(3)(-) influx (e.g., ocular ciliary epithelium, choroid plexus, and airway epithelium).

[Effects of IL-1 receptor antagonist on the level of cytokine in the rat corneal grafts and aqueous humor after corneal transplantation].

OBJECTIVE: By detecting the expression of IL-1RI and TGF-beta(1) on the normal rat cornea and graft, and the amount of IL-1 beta in the aqueous humor of normal rat eye and the eye after keratoplasty, to investigate the relationship between these cytokines and graft rejection and to observe the effects of IL-1 receptor antagonist (IL-1ra) on graft rejection. METHODS: All rats after keratoplasty were divided into five groups. Immunohistochemistry method and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of IL-1RI and TGF-beta(1) on the normal rat cornea and graft and the amount of IL- 1 beta in the aqueous humor of normal rat eye and the eye after keratoplasty at different time points: pre-rejection, acute-rejection and two weeks after surgery. RESULTS: IL-1RI could be detected in normal rat cornea. TGF-beta(1) expressed mainly in the epithelium of normal cornea, especially the basal cell layer and the basement membrane. After keratoplasty, IL-1RI and TGF-beta(1) could be detected in the corneal epithelium, stroma and endothelium, and the level of expression decreased in sequence as negative control group, 50 micro g IL-1ra group, 100 micro g IL-1ra group, 200 micro g IL-1ra group and dexamethasone group. In the acute rejection period, the expression of IL-1RI and TGF-beta(1) in the 200 micro g IL-1ra group was less than that of the 50 micro g IL-1ra group, the difference was significant (P < 0.01). The expression of IL-1RI and TGF-beta(1) in the negative control group was higher than that of all experimental groups, the difference was significant (P < 0.01). IL-1 beta was detected in normal aqueous humor; the mean level was (96.0 +/- 11.3) ng/L. In the eye after keratoplasty, the IL-1 beta level increased significantly compared to normal aqueous humor (P < 0.01). In the acute rejection period, the quantity of IL-1 beta reached its peak at (552.2 +/- 68.3) ng/L in the negative control group, which was the highest quantity of IL-1 beta in all experimental groups (P < 0.01). The IL-1 beta level in all experimental groups in the pre-rejection period had no difference compared with that in the acute rejection period (P > 0.05), but the level of IL-1 beta in the pre-rejection and rejection periods was significantly different compared with that in the post-rejection period (P < 0.01). CONCLUSIONS: IL-1RI and TGF-beta(1) play a active role in the corneal graft immunogenic rejection. IL-1 beta is a key factor in starting corneal graft rejection. The keratoplasty graft rejecting reaction can be reduced and mean survival time can be prolonged by IL-1ra, which inhibits the expression of IL-1RI and TGF-beta(1) and decreases the level of IL-1 beta in the aqueous humor.

Inhibition of carbonic anhydrase activity in cultured bovine corneal endothelial cells by dorzolamide.

PURPOSE: Fluid transport by the corneal endothelium is dependent on the presence of HCO(3)(-) and the activity of carbonic anhydrase (CA)-II and -IV, the cytoplasmic and membrane-bound CAs, respectively. This study was conducted to examine the inhibition of CA activity in cultured bovine corneal endothelial cells (BCECs) by dorzolamide, a topical CA inhibitor used in glaucoma therapy. METHODS: BCECs were grown on glass coverslips and then perfused with HCO(3)(-)-free Ringer's. The inward flux of CO(2) was induced by exposure to CO(2)-HCO(3)(-) Ringer's and the opposing outward flux by returning to HCO(3)(-)-free Ringer's. Consequent transients in intracellular pH (pH(i)) were measured using the pH-sensitive fluorescent dye 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). During the inward flux of CO(2,) the maximum rate of change of pH(i) was taken as a quantitative measure of the overall CA activity in BCECs. RESULTS: Exposure to CO(2)-HCO(3)(-) Ringer's led to a transient decrease in pH(i) (component A), followed by a rapid increase to a new steady state (component B). However, when the CO(2)-HCO(3)(-) Ringer's was removed, the pH(i) increased transiently (component C) and then rapidly returned to the original pH(i) (component D). Component A, caused by an inward flux of CO(2) and its subsequent hydration by CA-II, was blocked by dorzolamide in a dose-dependent manner with an 50% inhibitory concentration (IC)(50) of 2.4 micro M (95% confidence interval: 0.5 -10.85 microM). However, the inhibition of the outward flux of CO(2), inward flux of HCO(3)(-), and outward flux of HCO(3)(-) (associated with components C, B, and D, respectively) was not dose dependent. Cells that were exposed to 500 nM of the drug for longer than 30 minutes did not show a significantly greater inhibition of any of the components. Dorzolamide and acetazolamide (500 microM) did not show additive inhibition of any of the components (P = 0.13; n = 6). CONCLUSIONS: Dorzolamide significantly inhibits CA activity in BCECs at micromolar levels. Because these levels are encountered in the cornea and aqueous humor after topical administration, dorzolamide may compromise corneal hydration control, especially when the functional reserve of corneal endothelium is low. Dorzolamide does not appear to accumulate in the cells, because the inhibition of CA-II did not increase after prolonged exposure to the drug.