The influence of soft contact lenses on the intraocular pressure measurement

Purpose

To evaluate the influence of silicone hydrogel contact lenses on the intraocular pressure (IOP) measurement using Goldmann applanation tonometry (GAT), non-contact tonometry (NCT), and Pascal dynamic contour tonometry (DCT).

Methods

We included in the study 40 eyes of 40 patients who did not have any ocular or systemic diseases or contraindications to contact lens use. We measured and recorded the IOP values of each patient using NCT without and with contact lenses (groups 1 and 2, respectively), using DCT without and with contact lenses (groups 3 and 4, respectively), and using GAT without contact lenses (group 5).

Results

The mean IOP value of group 1 was 14.55±2.95 mm Hg and 13.92±2.58 mm Hg in group 2. We detected no statistically significant difference between group 1 and group 2 (P=0.053). The mean IOP values for group 3 and group 4 were 16.26±2.33 mm Hg and 15.19±2.40 mm Hg, respectively. We detected a statistically significant difference between groups 3 and 4 (P=0.005). Group 5''s mean IOP value was 12.97±2.65 mm Hg. IOP values measured with DCT were statistically significantly higher compared with IOP values measured with NCT and GAT (P<0.0001 and P<0.0001, respectively). Additionally, IOP values measured with NCT were statistically significantly higher compared with IOP values measured with GAT (P<0.0001).

Conclusion

According to the results of our study, silicone hydrogel soft contact lens use does not significantly affect IOP values measured with NCT, but it affects IOP values measured with DCT.     

Comparison of iCare tonometer and Goldmann applanation tonometry in normal corneas and in eyes with automated lamellar and penetrating keratoplasty

Purpose

To compare intraocular pressure (IOP) measurements with Goldmann applanation tonometry (GAT) and iCare tonometry in normal and post-keratoplasty corneas and to assess the influence of central corneal thickness (CCT), corneal curvature (CC), and corneal astigmatism (CA) on IOP.

Methods

This prospective cross-sectional study included one eye of 101 subjects with normal corneas (58 healthy subjects, 43 glaucoma); and 90 post-keratoplasty patients: 34 penetrating keratoplasties (PK); 20 automated-lamellar-therapeutic keratoplasties (ALTK); 19 Descemet-stripping-automated-endothelial keratoplasties (DSAEK); 17 edematous grafts. All subjects underwent GAT and iCare IOP measurements in random order, and CCT, CC, and CA evaluation. The Bland–Altman method and multivariate regression analysis were used to assess inter-tonometer agreement and the influence of CCT, CC, and CA on IOP.

Results

iCare significantly underestimated IOP in all groups compared with GAT (GAT minus iCare of 3.5±3.5 mm Hg, P<0.001), but overestimated IOP in the edematous grafts (GAT minus iCare of −6.5±1.9 mm Hg, P<0.001). In normal corneas, both tonometer measurements were directly related to CCT values; iCare readings appeared inversely related to CC. There was no significant relationship between IOP and CCT, CC and CA in post-keratoplasty eyes, except between CC and iCare measurements for PK eyes.

Conclusions

The agreement between GAT and iCare was clinically acceptable in control, ALTK and DSAEK groups, and poor in PK and edematous grafts eyes. In normal corneas, GAT was significantly affected by CCT; iCare was influenced by CCT and CC. The iCare appeared less influenced by corneal edema when compared with GAT. High IOP readings taken with both tonometers in grafts should raise suspicion of true elevated IOP.     

Comparation of the new rebound tonometer IOPen and the Goldmann tonometer, and their relationship to corneal properties

Purpose

To compare the intraocular pressures (IOPs) obtained with the IOPen rebound tonometer, Goldmann applanation tonometer (GAT) and the ocular response analyzer (ORA) and investigate the effects of corneal biomechanical properties on IOPen measurements.

Methods

A total of 198 normal eyes were included in this cross-sectional and randomized study. Three measurements were taken using IOPen. Agreement between tonometers was calculated using the Bland and Altman limits of agreement (LoA) analysis.

Results

The median IOPen IOP was 3 mm Hg below the GAT (P<0.001), 3 mm Hg below the ORA IOP similar to Goldmann (IOPg), and 3 mm Hg below the ORA IOP corrected using corneal parameters (IOPcc)(P<0.01). The LoA width between the IOPen and GAT IOPs varied between 13.92 (mean IOPen IOP) and 15.99 mm Hg (third IOPen measurement). The central corneal thickness (CCT) was unrelated to IOPen measurements (P>0.05). Corneal hysteresis (CH) and corneal rigidity factor (CRF) were correlated with IOPen and GAT.

Conclusions

IOPen underestimated the IOP compared with GAT and ORA. The effect of measurement quality or measurement order on IOPen was low. CCT did not affect the IOPen, but the CH and CRF did. The LoA width between the IOPen and GAT IOPs was higher than between the ORA IOPg or ORA IOPcc and GAT IOPs.     

Corneal hysteresis in patients with dry eye

Purpose

To measure corneal hysteresis and intraocular pressure (IOP) in patients with dry eye and to compare with normal subjects.

Methods

This cross-sectional study consists of 70 eyes of 40 patients with dry eye (group 1) and 75 eyes of 40 normal subjects (group 2). Eyes were diagnosed as dry eye or normal according to the clinical symptoms, biomicroscopical evaluation, and Schirmer test. Corneal hysteresis (CH), corneal resistance factor (CRF), and cornea-compensated intraocular pressure (IOPcc) were measured by the Ocular Response Analyser (ORA).

Results

Mean CH values were 10.56±0.25 mm Hg and 10.34±0.26 mm Hg, mean CRF values were 10.75±0.28 mm Hg and 10.70±0.28 mm Hg, mean CCT values were 542±3.20 μm and 543±3.89 μm in group 1 and group 2, respectively. There was no statistically significant difference between the groups for these three parameters. IOPcc values measured with ORA were 15.73±0.36 mm Hg in group 1 and 16.60±0.33 mm Hg in group 2, and there was no statistically significant difference between the two groups.

Conclusions

Corneal biomechanical parameters such as CH and CRF are not influenced in dry eye. Also statistical difference was not found between the two groups according to CCT and IOPcc values.     

The effect of orbital decompression surgery on refraction and intraocular pressure in patients with thyroid orbitopathy

Purpose

To investigate the effect of orbital decompression surgery in thyroid orbitopathy (TO) on both refractive status and intraocular pressure (IOP).

Patients and methods

A prospective, multicentre, consecutive audit of patients undergoing thyroid decompression surgery. Indications for surgery included cosmetically unacceptable proptosis or corneal exposure. Exclusion criteria included the following: previous orbital surgery, glaucoma, corneal disease, steroid use in the preceding 12 months, or an acute optic neuropathy. Automated refraction, keratometry, pachymetry, Hertel exophthalmometry, and IOP were recorded at 1 month pre- and 3 months postoperatively. IOP using the Tono-Pen (mean of three readings) was measured in the primary, upgaze, and downgaze positions.

Results

Data were collected from 52 orbits of 33 patients (East Grinstead, New York, and Adelaide). There was no significant difference between pre- and postoperative data for sphere, cylinder, or central corneal thickness (CCT). The mean spherical equivalent was −0.43±1.49 D pre-operatively and −0.28±1.52 D postoperatively. The steepest meridian of corneal curvature was 93.1 degrees pre- and 94.2 degrees postoperatively, with no significant difference. Mean IOP significantly decreased when measuring by Goldmann applanation tonometry (GAT) (2.28 mm Hg, ^* P=0.001) and Tono-Pen (3.06 mm Hg, ^* P=<0.0001). IOP measured in upgaze was significantly greater than that in the primary position. Regression analysis between change in IOP and either Hertel exophthalmometry or the number of orbital walls decompressed was non-significant (^*Student''s t-test).

Conclusion

Patients with TO undergoing orbital decompression had, on average, with-the-rule astigmatism not affected by orbital decompression surgery. IOP was significantly reduced by decompression surgery although no relationship between IOP and the degree of decompression was observed.     

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients

Purpose

To investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG).

Methods

Untreated POAG patients (IOP >21 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. The mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patient''s systemic and ocular characteristics.

Results

A total of 42 patients were included (mean age, 66.7±11.8 years). After a mean IOP reduction of 47.3±11.9%, significant changes were observed in cup area and volume, and in rim area and volume (P<0.01), but not in mean cup depth (P=0.80). Multiple regression analysis (controlling for baseline IOP and magnitude of IOP reduction) showed that CH (r²=0.17, P<0.01) and diabetes diagnosis (r²⩾0.21, P<0.01) were negatively correlated with the magnitude of changes in ONH parameters, whereas the cup-to-disc ratio was positively correlated (r²=0.30, P<0.01). Age, race, disc area, and CCT were not significant (P⩾0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (P<0.01).

Conclusions

Different systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP.     

The biomechanical properties of the cornea in patients with systemic lupus erythematosus

Pupose:

The purpose of this study was to compare the biomechanical properties of the cornea and intraocular pressure (IOP) between patients with systemic lupus erythematosis (SLE) and age-matched controls.

Patients and Methods:

In this prospective study, 30 healthy individuals (control group) and 30 patients with SLE (study group) underwent Reichert ocular response analyzer (ORA) measurements. In the right eye of each participant, the corneal hysteresis (CH), corneal resistance factor (CRF), and Goldman-related IOP (IOPg) were recorded using the ORA.

Results:

Mean CH, CRF, IOPg were significantly different between groups. Mean CH was 10.2±0.6 mm Hg in the study group and 11.3±1.3 in the control group (P=0.02); mean CRF was 9.7±1.1 mm Hg and 11.9±1.5 mm Hg, respectively (P=0.001). Mean IOP_g was 13.9±2.9 mm Hg in the study group and 16.9±2.6 mm Hg in the control group (P=0.001).

Conclusion:

The biomechanical properties of the cornea are altered in patients with SLE compared with normal controls. These findings should be taken into account when measuring IOP values in patients with SLE as IOP readings may be underestimated in SLE eyes.     

Travoprost 0.004%/timolol 0.5%-fixed combination with and without benzalkonium chloride: a prospective, randomized, doubled-masked comparison of safety and efficacy

Purpose

The purpose of this study is to compare the safety and intraocular pressure (IOP)-lowering efficacy of travoprost/timolol in a benzalkonium chloride (BAK)-free fixed combination preserved with polyquaternium-1 (TRA/TIM BAK-free), with travoprost/timolol-fixed combination preserved with BAK (TRA/TIM), in patients with open-angle glaucoma or ocular hypertension.

Methods

In this prospective randomized controlled trial, subjects with IOP of at least 22 mm Hg in one or both eyes at 0900 h, and IOP of at least 21 mm Hg in one or both eyes at 1100 h and 1600 h at two eligibility visits were randomly assigned to receive either TRA/TIM BAK-free (n=195) or TRA/TIM (n=193), dosed once daily in the morning (0900 h) for 6 weeks. IOP was assessed at 0900 h, 1100 h, and 1600 h at each scheduled visit (baseline, 2 and 6 weeks after randomization).

Results

Mean IOP reduction across all visits and time points was 8.0 mm Hg in the TRA/TIM BAK-free group and 8.4 mm Hg in the TRA/TIM group (P=0.0943). The difference in mean IOP between groups ranged from 0.2 to 0.7 mm Hg across visits and time points, with a mean pooled difference of 0.4 mm Hg (95% CI: −0.1 to 0.8), demonstrating equivalence of the two formulations. The most common drug-related adverse event was hyperemia of the eye (ocular hyperemia and conjunctival hyperemia combined), occurring in 11.8% of the TRA/TIM BAK-free group and 13.0% of the TRA/TIM group.

Conclusion

Travoprost/timolol BAK-free demonstrated equivalence to travoprost/timolol preserved with BAK in efficacy. No clinically relevant differences in the safety profiles of travoprost/timolol BAK-free and travoprost/timolol preserved with BAK were identified.     

Comparison of trabeculectomy and Ex-PRESS implantation in fellow eyes of the same patient: a prospective, randomised study

Purpose

To compare intraocular pressure (IOP) over time after standard trabeculectomy vsEx-PRESS implantation in patients with bilateral primary open-angle glaucoma (POAG).

Design

Prospective, randomised study.

Patients and methods

This study included adult patients with bilateral POAG necessitating surgery. Each patient underwent trabeculectomy in one eye and Ex-PRESS implantation under a scleral flap in the other eye according to randomised contralateral allocations. Efficacy was assessed by IOP values and success rates (IOP threshold and/or need for topical glaucoma medication) during 30 months. Statistical analysis included Generalised Estimate Equation and Cox Survival models, and paired t-tests.

Results

Thirty eyes of 15 patients were studied for a mean of 23.6 months (SD, ±6.9). At the last follow-up visit, mean pre-operative IOP decreased from 31.1 (±14.2) to 16.2 (±1.5) mm Hg after trabeculectomy, and from 28.1 (±9.0) to 15.7 (±1.8) mm Hg after Ex-PRESS implantation (P=0.001). The mean number of anti-glaucoma medicines prescribed at the last follow-up decreased from 3.7 pre-operatively (both groups) to 0.9 after trabeculectomy vs0.3 after Ex-PRESS implantation (P=0.001). Complete success rates (5P=0.0024). Postoperative complications were more frequent after trabeculectomy (33%) compared with Ex-PRESS (20%), with four trabeculectomy eyes (27%) needing postoperative interventions, compared with none with Ex-PRESS.

Conclusions

Trabeculectomy and Ex-PRESS implantation provided similar IOP control, but the Ex-PRESS group had a lower rate of complications, fewer postoperative interventions, and needed less glaucoma medications.     

Twenty-four hour efficacy with the dorzolamide/timolol-fixed combination compared with the brimonidine/timolol-fixed combination in primary open-angle glaucoma

Aim

The aim of this study is to compare the 24-hour efficacy of dorzolamide/timolol-fixed combination (DTFC) and brimonidine/timolol-fixed combination (BTFC) in primary open-angle glaucoma (POAG).

Methods

One eye each of 77 POAG patients was included in this prospective, observer-masked, crossover comparison. Following a 2-month timolol run-in period, patients had three intraocular pressure (IOP) measurements at 1000, 1200 and 1400 h while on timolol treatment. Patients showing at least a 20% IOP reduction on timolol were randomised to 3 months of therapy with DTFC or BTFC, and then were crossed over to the opposite therapy.

Results

Sixty POAG patients completed the study. The mean 24-hour IOP was significantly reduced with both the fixed combinations compared with the timolol-treated diurnal IOP (P<0.001). When the two fixed combinations were compared directly, DTFC demonstrated a lower mean 24-hour IOP level as compared with BTFC (mean difference: −0.7 mm Hg, 95% confidence interval (CI): (−1.0, −0.3), P<0.001). At two individual time points, DTFC significantly reduced IOP more than BTFC: at 1800 h (−1.0 mm Hg, 95% CI (−1.6,−0.5), P=0.001) and at 0200 (−0.9 mm Hg, 95% CI: (−1.4,−0.5), P=0.001). No significant difference existed for the other time points.

Conclusion

Both the fixed combinations significantly reduce 24-hour IOP in POAG. DTFC provided significantly better 24-hour efficacy.     

Comparison of intraocular pressure measurements with different contact tonometers in young healthy persons

AIM: To analyze the correlation of Goldmann applanation tonometer (GAT), I-Care tonometer and Tono-Pen tonometer results in young healthy persons, and to investigate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements recorded with these tonometers. METHODS: We conducted a pilot clinical study in 78 eyes of 78 subjects aged 22-28 years old (44 women and 34 men; mean age 23.8±1.19y). IOP was measured using GAT, I-Care and Tono-Pen tonometers, followed by measurements of CCT. Statistical analysis was performed using SPSS 20.0. RESULTS: The mean IOPs and standard deviation (±SD) for GAT, I-Care and Tono-Pen were 15.62±2.281 mm Hg, 16.29±2.726 mm Hg and 16.32±2.393 mm Hg, respectively. The mean CCT was 555.15±29.648 μm. Clear positive correlations between GAT and I-Care, GAT and Tono-Pen, and I-Care and Tono-Pen tonometers were found (r=0.867, P<0.001; r=0.861, P<0.001; r=0.915, P<0.001, respectively). In comparison between devices, Bland–Altman analysis showed a significant mean difference (MD) in the measurements by GAT and I-Care of ?0.679 mm Hg and by GAT and Tono-Pen of ?0.705 mm Hg ( P<0.001), but there was no significant difference between I-Care and Tono-Pen ( P>0.05). Both non-gold standard tonometers were affected by CCT; that is, both I-Care and Tono-Pen tonometer values were significantly higher with higher CCT means (>555 μm; MD=?1.282, P<0.001; MD=?0.949, P<0.001, respectively) compared with GAT. CONCLUSION: Both I-Care and Tono-Pen tonometers overestimated IOP compared with the GAT values. Either the I-Care or Tono-Pen tonometer could be used instead of GAT because there was no significant difference between their results. Higher CCT values (>555 μm) were associated with overestimated IOP values.     

Inflammatory ocular hypertension syndrome (IOHS) in patients with syphilitic uveitis

Aim

To determine the prevalence and clinical characteristics of the inflammatory ocular hypertension syndrome (IOHS) in patients with uveitis and serological evidence of syphilis.

Methods

A retrospective, observational case review of 39 consecutive patients with uveitis and serological evidence of syphilis was carried out between January 1977 and December 2001. Other causes of uveitis were excluded. The prevalence and clinical characteristics of IOHS among patients with uveitis and serological evidence of syphilis were documented. IOHS was defined as an increase in intraocular pressure (IOP) of more than 21 mm Hg that began at the onset of acute, recurrent, or chronic anterior chamber inflammation and reversed promptly with appropriate anti‐inflammatory or antimicrobial treatment.

Results

Of the 39 patients with uveitis and serological evidence of syphilis, eight eyes from seven patients (18%) presented with IOHS, a significantly higher prevalence than in the uveitis population at large (2.3%; p<0.001). Best‐corrected visual acuity varied from 20/20 to 20/200, with a median of 20/40, and three of the eight eyes (37.5%) had granulomatous features, including large keratic precipitates and, in two eyes, Koeppe nodules. Intraocular pressure varied from 23 to 51 mm Hg, with a mean of 36 and a median of 34. One patient had bilateral IOHS.

Conclusions

Syphilitic uveitis should be included in the differential diagnosis of IOHS along with more commonly recognised causes.     

Biodegradable collagen matrix implant vs mitomycin-C as an adjuvant in trabeculectomy: a 24-month, randomized clinical trial

Aim

To verify the safety and efficacy of Ologen (OLO) implant as adjuvant compared with low-dosage mitomycin-C (MMC) in trabeculectomy.

Methods

This was a prospective randomized clinical trial with a 24-month follow-up. Forty glaucoma patients (40 eyes) were assigned to trabeculectomy with MMC or OLO. Primary outcome includes target IOP at ≤21, ≤17, and ≤15 mm Hg; complete (target IOP without medications), and qualified success (target IOP regardless of medications). Secondary outcomes include bleb evaluation, according to Moorfields Bleb Grading System (MBGS); spectral domain optical coherence tomography (SD-OCT) examination; number of glaucoma medications; and frequency of postoperative adjunctive procedures and complications.

Results

The mean preoperative IOP was 26.5 (±5.2) in MMC and 27.3 (±6.0) in OLO eyes, without statistical significance. One-day postoperatively, the IOP dropped to 5.2 (±3.5) and 9.2 (±5.5) mm Hg, respectively (P=0.009). The IOP reduction was significant at end point in all groups (P=0.01), with a mean IOP of 16.0 (±2.9) and 16.5 (±2.1) mm Hg in MMC and OLO, respectively. The rates and Kaplan–Meier curves did not differ for both complete and qualified success at any target IOP. The bleb height in OLO group was higher than MMC one (P<0.05). SD-OCT analysis of successful/unsuccessful bleb in patients with or without complete success at IOP ≤17 mm Hg indicated a sensitivity of 83% and 73% and a specificity of 75% and 67%, respectively, for MMC and OLO groups. No adverse reaction to OLO was noted.

Conclusions

Our results suggest that OLO implant could be a new, safe, and effective alternative to MMC, with similar long-term success rate.     

Deep sclerectomy with mitomycin C in eyes with failed glaucoma surgery and pseudophakia

Purpose

To report outcomes of deep sclerectomy (DS) with intraoperative mitomycin C (MMC) application in eyes with previous failed glaucoma surgery (GS) and/or cataract extraction (CE).

Patients and methods

Single-surgeon case series of 82 eyes of 82 patients undergoing DS with MMC. The patients had previous CE with IOL and/or conjunctival GS and treated intraocular pressure (IOP) >18 mm Hg. MMC (0.2 mg/ml) was applied for 2–3 min before scleral flap dissection. Complete success was defined as IOP between 6 and 21 mm Hg or a reduction of 20% from baseline without medications. Reoperation for glaucoma or related complications, or loss of light perception vision was considered as failure.

Results

Mean follow-up was 57.7±22.4 months with 78% of patients completing the 3-year follow-up. Mean IOP decreased from 24.0 mm Hg (22.3–25.6, 95% confidence intervals) to 13.4 mm Hg (12.0–14.2) at 3 years after surgery (P<0.001). There was a significant decrease in the number of glaucoma medications from 2.0±1 preoperatively, to 0.3±0.7, 3 years after surgery. Kaplan–Meier cumulative success rates were 85.6% at 1 year, 80.0% at 2 years, and 76% at 3 years. At 3 years, IOP was maintained <19 and 15 mm Hg in 83 and 70% of eyes, respectively. Fourteen eyes (17.1%) had complications. Delayed hypotony (IOP <6 mm Hg) was the commonest complication in five eyes (6.1%).

Conclusion

DS with MMC appears to be a safe and effective surgical procedure for eyes with previous intraocular surgery.     

Increased intraocular pressure on the first postoperative day following resident-performed cataract surgery

Purpose

The aim of this study was to investigate the incidence of intraocular pressure (IOP) elevation after resident-performed cataract surgery and to determine variables, which influence postoperative day 1 (POD1) IOP.

Methods

In all, 1111 consecutive cataract surgeries performed only by training residents between 1 July 2001 and 30 June 2006 were included. Elevated IOP was defined as ≥23 mm Hg. Surgeries were classified according to the presence of POD1-IOP elevation. Fisher''s exact test and Student t-test were used to compare both groups. Multivariate analyses using generalized estimating equations were performed to investigate predictor variables associated with POD1-IOP elevation.

Results

The average preoperative IOP was 16.0±3.2 mm Hg and the average POD1-IOP was 19.3±7.1 mm Hg, reflecting a significant increase in IOP (P<0.001, paired t-test). The incidence of POD1-IOP elevation ≥23 mm Hg was 22.0% (244/1111). Presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length were frequently encountered variables in the POD1-IOP elevation group (all P<0.05). Using a multivariate analysis, presence of glaucoma (P=0.004, OR=2.38; 95% confidence interval (95% CI)=1.31–4.30), presence of ocular hypertension (P=0.003, OR=6.09; 95% CI=1.81–20.47), higher preoperative IOP (P<0.001, OR=3.73; 95% CI=1.92–7.25), and longer axial length (P=0.01, OR=1.15; 95% CI=1.03–1.29) were significant predictive factors for POD1-IOP elevation.

Conclusions

IOP elevation on the first postoperative day following resident-performed cataract surgery occurred frequently (22.0%). Increased early postoperative IOP was associated with presence of glaucoma and ocular hypertension, higher preoperative IOP, and longer axial length.     

Assessment of intraocular pressure measured by Reichert Ocular Response Analyzer, Goldmann Applanation Tonometry, and Dynamic Contour Tonometry in healthy individuals

AIM: To investigate the accuracy of intraocular pressure (IOP) as measured by a Reichert Ocular Response Analyzer (ORA), as well as the relationship between central corneal thickness (CCT) and IOP as measured by ORA, Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT). METHODS: A total of 158 healthy individuals (296 eyes) were chosen randomly for measurement of IOP. After CCT was measured using A-ultrasound (A-US), IOP was measured by ORA, GAT, and DCT devices in a randomized order. The IOP values acquired using each of the three tonometries were compared, and the relationship between CCT and IOP values were analyzed separately. Two IOP values, Goldmann-correlated IOP value (IOPg) and corneal-compensated intraocular pressure (IOPcc), were got using ORA. Three groups were defined according to CCT: 1) thin cornea (CCT<520μm); 2) normal-thickness cornea (CCT: 520–580μm); and 3) thick cornea (CCT>580μm) groups. RESULTS: In normal subjects, IOP measurements were 14.95±2.99mmHg with ORA (IOPg), 15.21±2.77mmHg with ORA (IOPcc), 15.22±2.77mmHg with GAT, and 15.49±2.56mmHg with DCT. Mean differences were 0.01±2.29mmHg between IOPcc and GAT (P>0.05) and 0.28±2.20mmHg between IOPcc and DCT (P>0.05). There was a greater correlation between IOPcc and DCT (r=0.946, P=0.000) than that between IOPcc and GAT (r=0.845, P=0.000). DCT had a significant correlation with GAT (r=0.854, P=0.000). GAT was moderately correlated with CCT (r=0.296, P<0.001), while IOPcc showed a weak but significant correlation with CCT (r=?0.155, P=0.007). There was a strong negative correlation between CCT and the difference between IOPcc and GAT(r=-0.803,P=0.000), with every 10μm increase in CCT resulting in an increase in this difference of 0.35mmHg. The thick cornea group (CCT>580μm) showed the least significant correlation between IOPcc and GAT (r=0.859, P=0.000); while the thin cornea group (CCT＜520μm) had the most significant correlation between IOPcc and GAT (r=0.926, P=0.000). The correlated differences between IOPcc and DCT were not significant in any of the three groups (P>0.05). CONCLUSION: Measurement of IOP by ORA has high repeatability and is largely consistent with GAT measurements. Moreover, the ORA measurements are affected only to a small extent by CCT, and are likely to be much closer to the real IOP value than GAT.     

Comparing acromegalic patients to healthy controls with respect to intraocular pressure,central corneal thickness,and optic disc topography findings

Aims:

The aim was to compare the intraocular pressure (IOP), central corneal thickness (CCT), and optic disc topography findings of biochemically controlled acromegalic patients and the control group and to evaluate the effect of the duration of acromegaly and serum growth hormone and insulin-like growth factor-1 (IGF-1) levels on these ocular parameters.

Materials and Methods:

IOP measurement with Goldmann applanation tonometry, CCT measurement with ultrasonic pachymetry, and topographic analysis with Heidelberg retinal tomograph III were performed on 35 biochemically controlled acromegalic patients and 36 age- and gender-matched controls.

Results:

Mean IOP and CCT were 14.7 ± 2.9 mmHg and 559.5 ± 44.9 μm in the acromegaly patients and 13.0 ± 1.6 mmHg and 547.1 ± 26.7 μm in controls (P = 0.006 and P = 0.15, respectively). A significant moderate correlation was found between the duration of acromegaly and CCT (r = 0.391) and IOP (r = 0.367). Mean retinal nerve fiber layer (RNFL) thickness was significantly lower in the acromegalic patients (0.25 ± 0.05 mm) as compared to controls (0.31 ± 0.09 mm) (P = 0.01). A significant moderate correlation was detected between IGF-1 level and disc area (r = 0.362), cup area (r = 0.389) and cup volume (r = 0.491).

Conclusion:

Biochemically controlled acromegalic patients showed significantly higher CCT and IOP levels and lower RNFL thickness compared to healthy controls and the duration of disease was correlated with CCT and IOP levels.     

Intraocular pressure and ocular pulse amplitude using dynamic contour tonometry and contact lens tonometry

Background

The new Ocular Dynamic Contour Tonometer (DCT), investigational device supplied by SMT (Swiss Microtechnology AG, Switzerland) allows simultaneous recording of intraocular pressure (IOP) and ocular pulse amplitude (OPA). It was the aim of this study to compare the IOP results of this new device with Goldmann tonometry. Furthermore, IOP and OPA measured with the new slitlamp-mounted DCT were compared to the IOP and OPA measured with the hand-held SmartLens^®, a gonioscopic contact lens tonometer (ODC Ophthalmic Development Company AG, Switzerland).

Methods

Nineteen healthy subjects were included in this study. IOP was determined by three consecutive measurements with each of the DCT, SmartLens^®, and Goldmann tonometer. Furthermore, OPA was measured three times consecutively by DCT and SmartLens^®.

Results

No difference (P = 0.09) was found between the IOP values by means of DCT (mean: 16.6 mm Hg, median: 15.33 mm Hg, SD: +/- 4.04 mm Hg) and Goldmann tonometry (mean: 16.17 mm Hg, median: 15.33 mm Hg, SD: +/- 4.03 mm Hg). The IOP values of SmartLens^® (mean: 20.25 mm Hg, median: 19.00 mm Hg, SD: +/- 4.96 mm Hg) were significantly higher (P = 0.0008) both from Goldmann tonometry and DCT. The OPA values of the DCT (mean: 3.08 mm Hg, SD: +/- 0.92 mm Hg) were significantly lower (P = 0.0003) than those obtained by SmartLens^® (mean: 3.92 mm Hg, SD: +/- 0.83 mm Hg).

Conclusions

DCT was equivalent to Goldmann applanation tonometry in measurement of IOP in a small group of normal subjects. In contrast, SmartLens^® (contact lens tonometry) gave IOP readings that were significantly higher compared with Goldmann applanation tonometer readings. Both devices, DCT and SmartLens^® provide the measurement of OPA which could be helpful e.g. for the management of glaucoma.

     

Comparison of postoperative intraocular pressure changes between 23-gauge transconjunctival sutureless vitrectomy and conventional 20-gauge vitrectomy

Purpose

To compare the intraocular pressure (IOP) after 23-gauge transconjunctival sutureless vitrectomy (TSV) and conventional 20-gauge vitrectomy for various vitreoretinal diseases.

Methods

This was a retrospective interventional case series including 338 cases of 23-gauge TSV and 476 cases of 20-gauge vitrectomy with minimum follow-up period of 1 month. Postoperative 1 day, 1 week and 1 month IOPs were compared. Multiple regression analysis to assess the actual effect of gauge of vitrectomy on postoperative IOP was performed including intraoperative and postoperative factors influencing postoperative IOP as covariates.

Results

The mean IOP of 20-gauge vitrectomy was significantly higher than that of 23-gauge TSV (20.6±8.02 mm Hg vs12.8±4.48 mm Hg, P<0.001) at postoperative day 1, but the differences were not significant at postoperative 1 week and 1 month. The IOP pattern of 23-gauge TSV demonstrated more stable course than that of 20-gauge vitrectomy. At 1 day post vitrectomy, the incidence of hypertony was higher in 20-gauge, whereas that of hypotony was higher in 23-gauge. Among risk factors, the 20-gauge vitrectomy showed the strongest association with postoperative 1 day IOP rise.

Conclusion

Twenty-three-gauge TSV has stable and lower IOP in the early postoperative period than the 20-gauge vitrectomy. In patients whose retina and optic nerves are vulnerable to higher or fluctuating IOP, 23-gauge TSV may be more beneficial.     

Size of the neuroretinal rim and optic cup and their correlations with ocular and general parameters in adult Chinese: the Beijing eye study

Aim

To measure the size of the neuroretinal rim, the major variable in the quantitative analysis of the optic nerve head, and its correlations in adult Chinese in a population based setting.

Methods

The Beijing eye study—a population based, cross sectional cohort study—included 4439 subjects from among 5324 of age of 40+ years invited to participate (response rate 83.4%). This study included a random sample of 781 subjects with normal intraocular pressure (IOP), normal visual fields, and a normal optic nerve head; and a random sample of 84 subjects with an IOP >21 mm Hg. Colour optic disc photographs (30°) were examined morphometrically.

Results

In the normal group, the mean (SD) neuroretinal rim area was 1.70 (0.30) mm². It was significantly correlated with optic disc area (rim area = 0.43*disc area+0.67; p<0.001). It was not significantly associated with age, sex, or a known diagnoses of diabetes mellitus, arterial hypertension or hypotension, hyperlipidaemia, coronary heart disease, or cerebral haemorrhage.

Conclusions

In adult Chinese, the neuroretinal rim area measures 1.70 (0.30) mm² on optic disc photographs. It is statistically independent of age. Compared with data from studies in Western countries, the neuroretinal rim is larger in adult Chinese than in adult white populations, corresponding to a larger optic disc size in the Chinese.