Shiro Kawasaki

Screening for Dry Eye With Newly Developed Ocular Surface Thermographer

PURPOSE To evaluate the newly developed Ocular Surface Thermographer (TOMEY Corporation) for dry eye screening. DESIGN Prospective, controlled study. METHODS We studied 30 eyes of 30 patients diagnosed with dry eye (mean age ± standard deviation, 52.9 ± 17.1 years) and 30 eyes of 30 normal subjects (42.7 ± 17.0 years). The ocular surface temperature was measured immediately after eye opening and every second during 10 seconds of eye opening. The reliability of the measurements was determined by calculating intraclass correlation coefficients. Then, the correlations between the change in the ocular surface temperature and tear film break-up time, Schirmer I test values, and fluorescein staining scores were determined. RESULTS The measurements of the ocular surface temperature had a high degree of reliability. Immediately after eye opening, the temperature in the dry eye did not differ significantly from that in normal eyes in any of the 3 regions tested. The decrease in the ocular surface temperature in dry eyes was significantly greater than that in normal eyes (P < .001) at 10 seconds after eye opening. The decrease in the temperature of the cornea was correlated significantly with the tear film break-up time (r = -0.572; P < .001). When the changes in ocular surface temperature of the cornea were used as an index for dry eye, the sensitivity was 0.83 and the specificity was 0.80 after 10 seconds. CONCLUSIONS Measurements of the ocular surface temperature obtained with our newly developed Ocular Surface Thermographer after 10 seconds of eye opening may provide a simple, noninvasive screening test for dry eyes.

In Vivo Confocal Microscopic Evidence of Keratopathy in Patients with Pseudoexfoliation Syndrome

PURPOSE To measure the density of cells in different layers of the cornea and to determine whether morphologic changes of the subbasal corneal nerve plexus are present in eyes with the pseudoexfoliation (PEX) syndrome. METHODS Twenty-seven patients with unilateral PEX syndrome and 27 normal controls were investigated. All eyes underwent corneal sensitivity measurements with an esthesiometer and in vivo confocal microscopic study. Densities of the epithelial, stromal, and endothelial cells were measured. The density and tortuosity of the subbasal corneal nerve plexus were also evaluated. RESULTS Eyes with PEX syndrome had significantly lower cell densities in the basal epithelium (P = 0.003), anterior stroma (P = 0.007), intermediate stroma (P = 0.009), posterior stroma (P = 0.012), and endothelium (P < 0.0001) than in the corresponding layers of normal eyes. PEX eyes also had lower subbasal nerve densities and greater tortuosity of the nerves than normal eyes. Fellow eyes of patients with PEX also had significantly lower densities of the basal epithelial and endothelial cells than the normal eyes. Corneal sensitivity was significantly decreased in PEX eyes, and this was significantly correlated with the decrease of basal epithelial cell and subbasal nerve densities. CONCLUSIONS These results have shed light on understanding of the pathogenesis of decreased corneal sensitivity in eyes with PEX syndrome. PEX syndrome is probably a binocular condition for which keratopathy of the fellow eye also requires observation.

Evaluation of filtering bleb function by thermography

Aim: To determine whether thermography can be used to evaluate bleb function. Methods: The surface temperatures of filtering blebs from 39 eyes of 33 post-trabeculectomy patients were measured using thermography. We introduced a new parameter: the temperature decrease in the filtering bleb (TDB) where TDB = (mean temperature of the temporal and nasal bulbar conjunctiva)–(temperature of the filtering bleb). The eyes were classified into good and poor intraocular pressure (IOP) control groups according to the patients’ postoperative IOP. The morphological appearance of the filtering blebs were classified by slit-lamp images according to the Indiana Bleb Appearance Grading Scale. The differences in TDB were analysed statistically. Results: Mean overall scores were as follows. The TDB were 0.54 (SD 0.20)°C and 0.21 (SD 0.18)°C for the good and poor IOP control groups, respectively. The difference between the TDB of the two IOP control groups was significant (p<0.0001), but there was no significant relationship between morphological classification and TDB. Conclusions: Thermographic measurements suggest that functional blebs have lower temperatures than non-functional blebs, and their morphological appearances are not affected by their temperature. Thermography may be useful for the evaluation of bleb function.

Disruption of the Posterior Chamber–Anterior Hyaloid Membrane Barrier During Phacoemulsification and Aspiration as Revealed by Contrast-Enhanced Magnetic Resonance Imaging

OBJECTIVE To determine the effect of phacoemulsification and aspiration (PEA) in different surgical settings on the posterior chamber-anterior hyaloid membrane (AHM) barrier. METHODS Eighty enucleated porcine eyes divided into 8 groups underwent lens extraction at a bottle height of 35 or 95 cm by 1 of the following 4 procedures: standard PEA, standard PEA without hydrodissection (sPEA-), sPEA- including 5 minutes of irrigation of the anterior chamber, and sPEA- including 20 cycles of deflation (5 seconds each cycle) and inflation (10 seconds each cycle) of the anterior chamber. Distribution of gadopentetate dimeglumine (gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) in the irrigating fluid was assessed by magnetic resonance imaging (MRI). RESULTS The most common MRI pattern was the posterior chamber type, where Gd-DTPA was localized in the anterior and posterior chambers, followed by AHM detachment, in which Gd-DTPA was evident beneath the posterior lens capsule. The least common was AHM tear, in which Gd-DTPA entered the vitreous cavity through a tear in the AHM. Logistic regression analysis revealed prolonged irrigation (P< .001) and deflation/inflation of the anterior chamber (P< .001) as risk factors for AHM detachment and hydrodissection (P= .04) as a risk factor for AHM tear. CONCLUSION Changes in intraocular pressure can disrupt the posterior chamber-AHM barrier during PEA. CLINICAL RELEVANCE Cataract surgeons should reexamine their surgical settings to avoid unnecessary stress on the eye.

Evaluation of Allergic Conjunctivitis by Thermography

Purpose: To evaluate ocular surface temperature in assessing the efficacy of anti-allergic eye drops. Methods: Thirteen asymptomatic patients (24.7 ± 2.8 years) with proven seasonal allergic conjunctivitis due to cedar pollen were studied. A 0.025% levocabastine ophthalmic suspension was instilled in one eye (levocabastine eye) and artificial tears in the other eye (artificial tear eye) in a masked fashion 10 min prior to a conjunctival allergen challenge (CAC). Then, a drop of cedar pollen solution was dropped into the conjunctival sac to induce the allergic reaction. The surface temperature of the inferior bulbar conjunctiva was measured before and 30 min after the CAC with a newly developed non-contact ocular surface thermographer (OST). The degree of conjunctival injection and chemosis was also determined by slit-lamp biomicroscopy. The changes in the symptoms were evaluated by a questionnaire. Results: After the CAC, the temperature increased by 0.67 ± 0.10°C in the artificial tear eyes but by only 0.21 ± 0.06°C in the levocabastine eyes (p < 0.05). The score for conjunctival injection was 1.38 ± 0.24 and the chemosis score was 0.85 ± 0.25 for the artificial tear eyes and 0.62 ± 0.27 and 0.08 ± 0.08 in the levocabastine eyes (p < 0.01). The temperature increase was significantly correlated with the conjunctival injection scores (r = 0.63; p < 0.001). Conclusion: The significant correlation of the conjunctival surface temperature with the severity of the conjunctival allergic reaction indicates that the temperature measured by the OST can be used to objectively evaluate the efficacy of topical anti-allergic agents.

Influence of Elevated Intraocular Pressure on the Posterior Chamber-Anterior Hyaloid Membrane Barrier During Cataract Operations

OBJECTIVE To investigate the influence of elevated intraocular pressure on the posterior chamber-anterior hyaloid membrane (PC-AHM) barrier during cataract operations in ex vivo porcine eyes. METHODS A pressure transducer was connected to porcine eye anterior chambers (ACs). In experiment 1, ACs were perfused for 20 seconds with balanced salt solution containing 1.0-μm fluorescein beads (10 eyes per bottle height: 45, 85, 145, and 285 cm). In experiment 2, 5 ophthalmic viscosurgical devices with different molecular weights and sodium hyaluronate concentrations were infused into the ACs (20 eyes per ophthalmic viscosurgical device). After continuous curvilinear capsulorrhexis, hydrodissection was performed. After both experiments, PC-AHM barrier staining was evaluated through the Miyake-Apple view. RESULTS Types of fluorescein staining patterns were classified as AC, zonule of Zinn, AHM, AHM tear, and ruptured capsule. In experiment 1, plateau intraocular pressure and staining type were positively correlated (Spearman rank correlation; r = 0.703, P < .001). In experiment 2, mean peak intraocular pressure was significantly greater in the ruptured capsule-type eyes than in the AC-, zonule of Zinn-, AHM (P < .001), or AHM-tear-(P = .02) type eyes, as well as in the AHM- and AHM-tear-type eyes compared with the AC and zonule of Zinn type eyes (P < .001). Intraocular pressure was significantly higher in eyes infused with ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration (P < .05). CONCLUSIONS Stress on the PC-AHM barrier increases as intraocular pressure increases. Ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration might induce increased IOP during cataract operations. CLINICAL RELEVANCE To maintain normal PC-AHM barrier function, excessive intraocular pressure should be avoided during cataract operations.

Moxifloxacin as Postoperative Prophylaxis for Enterococcus faecalis-Induced Endophthalmitis After Cataract Surgery in Aphakic Rabbits

PURPOSE The development of endophthalmitis after cataract surgery often results in significant vision loss. Inhibition of bacterial proliferation in the anterior chamber using antibiotic eye drops is important to prevent endophthalmitis after cataract surgery. We aimed to determine the sensitivity of fluoroquinolones against Enterococcus faecalis ocular isolates and the efficacy of fluoroquinolones to prevent E. faecalis-induced endophthalmitis in aphakic rabbits. METHODS The minimum inhibitory concentrations (MICs) of moxifloxacin (MFLX) and levofloxacin (LVFX) used in ophthalmic solutions for 13 E. faecalis isolates obtained from the conjunctival sac or endophthalmitis cases were determined. Eye drops containing MFLX (0.5%), LVFX (0.5%), or saline were administered to aphakic rabbits with endophthalmitis induced by E. faecalis. The eye drops were administered immediately after lensectomy and at 3 and 6 h after cataract surgery (early instillation group) or immediately after lensectomy and at 12 and 15 h after cataract surgery (delayed instillation group). Bacterial growth, electroretinography (ERG), and slit-lamp examination (SLE) were determined throughout the course of infection. RESULTS In vitro susceptibility testing revealed that the MICs of MFLX for E. faecalis isolates were lower than those of LVFX. In the early ocular instillation groups, MFLX significantly improved SLE scores, ERG, and viable bacterial counts compared with LVFX and saline (all, P<0.05). There were no significant differences in any parameter between MFLX and saline in the delayed ocular instillation groups. CONCLUSIONS Early ocular instillation of MFLX delays retinal damage compared with LVFX when used to treat E. faecalis-induced endophthalmitis after cataract surgery.

Evaluation of a new method of irrigation and aspiration for removal of ophthalmic viscoelastic device during cataract surgery in a porcine model.

BackgroundTo determine if a method for irrigation and aspiration (I/A) during cataract surgery provides effective removal of ophthalmic viscoelastic device (OVD).MethodsJapanese porcine eyes were used to evaluate I/A performance with Technique 1 (the I/A tip placed on the center of the anterior surface of the IOL), Technique 2 (the I/A tip alternately pressed near the edge of the IOL optic anterior surface on one side and then the other to tilt the IOL back and forth), and Technique 3 (the I/A tip inserted behind the IOL optic, between it and the posterior capsule). Techniques 1 and 2 were compared using the Miyake-Apple posterior view video technique to visualize the flow of irrigation fluid containing triamcinolone acetonide particles behind the IOL. To check the efficacy of OVD removal from behind the IOL for of all three I/A techniques, OVD with fluorescein beads were inserted inside the lens capsule before implantation of the IOL. After each I/A technique, eyes were prepared for Miyake–Apple viewing and pictures of the lens capsule were taken using fluorescent microscopy. Residual fluorescein beads in the capsular bag were analyzed.ResultsTechnique 1 resulted in a straight flow of fluid behind the IOL, while Technique 2 resulted in a vortex flow. The average amount of OVD retained inside the capsule after using Technique 2 or 3 was significantly lower than after using Technique 1 (p <0.0001).ConclusionsTechnique 2 proved to remove more effectively fluorescein bead-labelled OVD under the IOL than Technique 1.

Ocular Penetration and Efficacy of Levofloxacin Using Different Drug-Delivery Techniques for the Prevention of Endophthalmitis in Rabbit Eyes with Posterior Capsule Rupture

PURPOSE To evaluate the effects of different drug-delivery techniques for levofloxacin (LVFX) in ocular penetration and the prevention of endophthalmitis using an aphakic rabbit model with posterior capsule rupture (PCR). METHODS LVFX was administered to aphakic rabbit eyes with or without PCR using eye drops (EDs), subconjunctival injection (SCI), or intracameral (IC) injection. The concentration of the drug in the vitreous and aqueous humors was estimated at 2 h after injection. In another study, aphakic rabbit eyes with PCR were inoculated with Enterococcus faecalis, immediately followed by 0.5% LVFX ED, 0.5% moxifloxacin (MFLX) ED, LVFX IC (500 μg/0.1 mL), or IC saline. EDs were administered 0, 3, and 6 h after surgery. Changes on electroretinography (ERG) and intraocular bacterial growth were determined sequentially until 48 h after inoculation. RESULTS The concentrations of LVFX at 2 h after IC were higher in the aqueous humor and the vitreous cavity of eyes with or without PCR, compared with EDs or SCI. Eyes treated with LVFX ED, MFLX ED, or IC saline showed a significantly greater reduction in b-wave amplitude on ERG at 48 h compared with eyes treated with LVFX IC. The number of bacteria recovered from the vitreous humor in eyes treated with IC LVFX at 48 h was significantly less than from eyes that received other treatments. CONCLUSION The LVFX IC was effective at suppressing endophthalmitis caused by E. faecalis in eyes with a PCR.

New side-view imaging technique for observing posterior chamber structures during cataract surgery in porcine eyes

BackgroundTo develop a side-view imaging technique for observing the dynamic behavior of posterior chamber structures (PCSs) in porcine eyes which mimics closed-eye cataract surgery in humans.MethodsEnucleated porcine eyes were placed into liquid nitrogen for 5 seconds and immediately bisected at about a 45-degree angle to the equatorial plane. The anterior portion was attached firmly to a glass slide with superglue and sprinkled with wheat flour. Phacoemulsification and aspiration (PEA) was performed as in humans on 10 consecutive porcine eyes. The movements of the PCSs were monitored through the glass slide with a high-resolution video camera set below the cut surface of the eye. The intraocular pressure (IOP) was monitored during the surgery. The highest IOP, operation time, and volume of irrigation fluid of 10 whole eyes were compared to that obtained from the bisected eyes glued to a glass slide. In a second set of experiments, the strength of the seal between the bisected eye and the glass slide was tested in three sets of eyes: 1) frozen eye fixed with superglue with wheat flour for 3 min; 2) frozen eye fixed with superglue for 3 min; and 3) non-frozen eye fixed with superglue for 30 min. The highest IOP that led to a disruption of the seal was compared among the three groups.ResultsPEA was successfully performed on 9 of 10 (90%) eyes with the movements of the PCSs clearly observed. The average maximum intraocular pressure of the 9 bisected eyes was 55.8 ± 4.7 mmHg and that for the 10 unbisected eyes was 55.3 ± 5.0 mmHg (P = 0.650). The frozen eye fixed with superglue in combination with wheat flour (Group 1) had the strongest sealing strength with an average IOP at the breaking point of 117.3 ± 36.2 mmHg.ConclusionsOur side-view imaging technique can be used to evaluate the changes of the PCSs during intraocular surgery and for surgical training of new residents.