Mini-incision cataract surgery and toric lens implantation for the reduction of high myopic astigmatism in patients with pellucid marginal degeneration

Purpose

To evaluate the clinical outcomes, safety, and efficacy of cataract surgery with the implantation of a toric intraocular lens (IOL) in eyes with stable pellucid marginal degeneration (PMD).

Methods

Eleven eyes (eight patients) diagnosed as stable PMD and cataract underwent mini-incision 2.2 mm cataract surgery followed by the implantation of hydrophobic toric aspheric IOL (AcrySof IQ Toric IOL, Alcon, Fort Worth, TX, USA). Perioperative variables of interest included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and corneal topography. Paired samples t-tests were used to analyze preoperative and postoperative visual acuity, astigmatism, and spherical equivalent (SE) parameters. Follow-up was 6 months.

Results

The mean CDVA was 0.62±0.26 logMAR preoperatively and 0.07±0.07 logMAR postoperatively. The mean preoperative sphere and cylinder was −3.14±3.58D and −4.84±2.02D, respectively. The mean postoperative manifest refractive sphere and cylinder was −0.30±0.51D and −0.81±1.51D, respectively. There was a significant reduction in refractive astigmatism after toric IOL implantation (P<0.002). The toric IOL axis rotation was <5° in all cases at the final follow-up.

Conclusions

Implantation of hydrophobic toric IOL was a safe and effective surgical procedure to correct mild to moderate stable PMD.     

Accuracy of axial length measurements from immersion B-scan ultrasonography in highly myopic eyes

AIM:To evaluate the accuracy of axial length (AL) measurements obtained from immersion B-scan ultrasonography (immersion B-scan) for intraocular lens (IOL) power calculation in patients with high myopia and cataracts.METHODS:Immersion B-scan, contact A-scan ultrasonography (contact A-scan), and the IOLMaster were used to preoperatively measure the AL in 102 eyes from 102 patients who underwent phacoemulsification and IOL implantation. Patients were divided into two groups according to the AL:one containing patients with 22 mm≤AL<26 mm(group A) and the other containing patients with AL≥26 mm (group B). The mean error (ME) was calculated from the difference between the AL measurement methods predicted refractive error and the actual postoperative refractive error.RESULTS:In group A, ALs measured by immersion B-scan (23.48±1.15) didn’t differ significantly from those measured by the IOLMaster (23.52±1.17) or from those by contact A-scan (23.38±1.20). In the same group, the standard deviation (SD) of the mean error (ME) of immersion B-scan (-0.090±0.397 D) didn’t differ significantly from those of IOLMaster (-0.095±0.411 D) and contact A-scan (-0.099±0.425 D). In group B, ALs measured by immersion B-scan (27.97±2.21 mm) didn’t differ significantly from those of the IOLMaster (27.86±2.18 mm), but longer than those measured by Contact A-scan (27.75±2.23 mm, P=0.009). In the same group, the standard deviation (SD) of the mean error (ME) of immersion B-scan (-0.635±0.157 D) didn’t differ significantly from those of the IOLMaster (-0.679±0.359 D), but differed significantly from those of contact A-scan (-0.953±1.713 D, P=0.028).CONCLUSION:Immersion B-scan exhibits measurement accuracy comparable to that of the IOLMaster, and is thus a good alternative in measuring AL in eyes with high myopia when the IOLMaster can’t be used, and it is more accurate than the contact A-scan.     

Agreement analysis of LENSTAR with other techniques of biometry

Purpose

To assess the agreement of the optical low-coherence reflectometry (OLCR) device LENSTAR LS900 with partial coherence interferometry (PCI) device IOLMaster and applanation and immersion ultrasound biometry.

Methods

We conducted the study at the Ophthalmology Clinic, University of Malaya Medical Center, Malaysia. Phakic eyes of 76 consecutive cataract patients were measured using four different methods: IOLMaster, LENSTAR and A-scan applanation and immersion ultrasound biometry. We assessed the method agreement in the LENSTAR-IOLMaster, LENSTAR-applanation, and LENSTAR-immersion comparisons for axial length (AL) and intraocular lens (IOL) power using Bland–Altman plots. For average K, we compared LENSTAR with IOLMaster and the TOPCON KR-8100 autorefractor-keratometer. SRK/T formula was used to compute IOL power, with emmetropia as the target refractive outcome.

Results

For all the variables studied, LENSTAR agreement with IOLMaster is strongest, followed by those with immersion and applanation. For the LENSTAR-IOLMaster comparison, the estimated proportion of differences falling within 0.33 mm from zero AL and within 1D from zero IOL power is 100%. The estimated proportion of differences falling within 0.5 D from zero average K is almost 100% in the LENSTAR-IOLMaster comparison but 88% in the LENSTAR-TOPCON comparison. The proportion of differences falling within 0.10 mm (AL) and within 1D (IOL power) in the LENSTAR-IOLMaster comparison has practically significant discrepancy with that of LENSTAR-applanation and LENSTAR-immersion comparisons.

Conclusions

In phakic eyes of cataract patients, measurements of AL, average K, and IOL power calculated using the SRK/T formula from LENSTAR are biometrically equivalent to those from IOLMaster, but not with those from applanation and immersion ultrasound biometry.     

Phakic intraocular lenses outcomes and complications: Artisan vs Visian ICL

Purpose

To evaluate the safety and visual outcomes of two phakic intraocular lenses (IOLs) for correction of high myopia: Artisan and Visian ICL (ICL).

Patients and methods

In this retrospective study, a phakic IOL was implanted in 68 highly myopic eyes of 34 patients; 42 eyes received an Artisan IOL, and 26 eyes received ICL IOL.

Results

All patients completed a 1-year follow-up. The mean preoperative spherical equivalent (SEQ) was −12.89±3.78, and −12.44±4.15 diopters (D) for Artisan and ICL (P=0.078), respectively. The mean postoperative (1-year) uncorrected distance visual acuity was 0.39±0.13 and 0.41±0.15 logMAR for Artisan and ICL, respectively (P=0.268). The mean postoperative (1-year) corrected distance visual acuity was 0.36±0.12 and 0.31±0.12 logMAR for Artisan and ICL, respectively (P=0.128). The mean postoperative SEQ was −0.86±0.5 and −0.63±0.38 D for Artisan and ICL, respectively (P=0.67). Intraocular pressure change at 1 year was 0.64±2.7 and 1.88±0.6 mm Hg for Artisan and ICL, respectively (P=0.77).

Conclusion

Artisan and ICL showed equal and comparable safety, predictability, and efficacy.     

Visual and Refractive Outcomes after Cataract Surgery with Implantation of a New Toric Intraocular Lens

Purpose

The aim of this study was to evaluate and report the visual, refractive and aberrometric outcomes of cataract surgery with implantation of the new aspheric Tecnis ZCT toric intraocular lens (IOL) in eyes with low to moderate corneal astigmatism.

Methods

We conducted a prospective study of 19 consecutive eyes of 17 patients (mean age: 78 years) with a visually significant cataract and moderate corneal astigmatism [higher than 1 diopter (D)] undergoing cataract surgery with implantation of the aspheric Tecnis ZCT toric IOL (Abbott Medical Optics). Visual, refractive and aberrometric changes were evaluated during a 6-month follow-up. Ocular aberrations as well as IOL rotation were evaluated by means of the OPD-Station II (Nidek).

Results

The six-month postoperative spherical equivalent and power vector components of the refractive cylinder were within ±0.50 D in all eyes (100%). Postoperative logMAR uncorrected and corrected distance visual acuities (UDVA/CDVA) were 0.1 (about 20/25) or better in almost all eyes (94.74%). The mean logMAR CDVA improved significantly from 0.41 ± 0.23 to 0.02 ± 0.05 (p < 0.01). No significant changes were found in corneal astigmatism (p = 0.73). The mean IOL rotation was 3.33 ± 1.94°. This parameter did not correlate with higher-order aberrations (r = −0.09, p = 0.73). A significant improvement in the Strehl ratio was also observed (p < 0.01), which was consistent with the significant reduction in higher-order aberrations (p = 0.02).

Conclusion

Cataract surgery with implantation of the aspheric Tecnis ZCT IOL is a predictable and effective procedure for visual rehabilitation in eyes with cataract and low to moderate corneal astigmatism, providing an excellent postoperative ocular optical quality.Key words: Tecnis ZCT, Aspheric toric intraocular lens, Cataract surgery, Higher-order aberrations     

Changes in choroidal thickness,axial length,and ocular perfusion pressure accompanying successful glaucoma filtration surgery

Purpose

To investigate the changes in choroidal thickness (CT), axial length (AL), and ocular perfusion pressure (OPP) accompanying intraocular pressure (IOP) reduction after trabeculectomy.

Methods

Thirty-nine eyes of 39 patients with primary open-angle glaucoma uncontrolled by medical therapy were included in this prospective and interventional study. All patients underwent a fornix-based trabeculectomy. The CT was measured by enhanced depth imaging-optical coherence tomography. IOP, AL, and systolic/diastolic blood pressure were also measured, and OPP was calculated. All measurements were performed at baseline and 1 month after surgery.

Results

The mean IOP was 25.0±5.8 mm Hg at baseline and 11.7±2.6 mm Hg after trabeculectomy (P<0.001), and the mean subfoveal CT was 295±84 mm Hg at baseline and 331±82 mm Hg after trabeculectomy (P<0.001). The mean AL was 23.64±0.98 mm at baseline and 23.54±0.96 mm after trabeculectomy (P<0.001), whereas the mean OPP was 38.8±6.2 mm Hg preoperatively, and 51.1±7.3 mm Hg postoperatively (P<0.001). The change in CT negatively correlated with the change in IOP (r=−0.785, P<0.001) and AL (r=−0.693, P<0.001), whereas it positively correlated with the change in OPP (r=0.418, P=0.008).

Conclusion

These results suggest that the large IOP decrease following trabeculectomy causes choroidal thickening. In addition, CT changes are associated with IOP and AL reduction as well as OPP increase.     

Prediction of Refractive Error in Combined Vitrectomy and Cataract Surgery With One-Piece Acrylic Intraocular Lens

Purpose

To compare the predicted and actual refractive errors of hydrophilic, one-piece, C-flex®570C (C-flex) intraocular lens (IOL) implantation in simultaneous vitrectomy and lens extraction in various conditions.

Methods

One hundred fifty-nine eyes of patients who had lens extraction between March 2004 and September 2005 were enrolled in a retrospective study. Group 1 had lens extraction and IOL implantation, and Group 2 had lens extraction and IOL implantation with vitrectomy. IOL calculation was done with axial length and keratometry measurements. The actual and predicted refractive errors were compared at 1 and 6 months postoperatively. The factors influencing the postoperative refractive outcomes were analyzed.

Results

The mean refractive predictive error (i.e., the actual minus predicted spherical equivalent) was +0.19±0.39 D (Diopter) and -0.26±0.45 D at 1 and 6 months postoperatively (all: p<0.001) in group 1, and -0.22±0.39 D and -0.06±0.62 D at 1 and 6 months postoperatively (p=0.013, p=0.399 respectively). In group 2, all surgical factors related to refractive errors were not statistically significant (all: p>0.05).

Conclusions

Refractive errors in combined surgery showed myopic shift of -0.50 D and -0.32 D at 1 and 6 months postoperatively compared with C-flex IOL implantation alone. With the hyperopic tendency of IOL and myopic tendency of vitrectomy, the combined surgery made postoperative refractive errors near emmetropia.     

Observing implantable collamer lens dislocation by panoramic ultrasound biomicroscopy

Purpose

Observe the image characteristics and dislocation of implantable collamer lenses (ICL) following their use to correct high myopia.

Methods

A total of 127 patients (242 eyes); 64 females (50.3%) and 63 males (49.7%) were included in this retrospective study with ICL V4 implantation and mean spherical equivalent −9.08±2.04 diopters (D). Panoramic ultrasound biomicroscopy (UBM) was utilized to observe anterior segment morphology and ICL location at various follow-up periods (1 week preoperative, followed by 1, 3, 6, and yearly postoperative).

Results

Twenty-eight ICL eyes (11.2%) were noted to have abnormal postoperative positioning. The central vault of 12 eyes was too high with ICL decentration, mean central vault 1.14±0.39 mm; 10 eyes were too low but without ICL decentration, mean central vault 0.13±0.11 mm. The remaining subjects were only ICL decentration without abnormal central vault, mean central vault was 0.54±0.28 mm.

Conclusions

This study shows the abnormal characteristics regarding ICL locations. The ICL dislocation closely correlates with the central vault. The ICL dislocation is the primary cause of several postoperative complications. Panoramic UBM is one of the most effective imaging means to observe the ICL positioning and its stability after implantable surgery.     

Comparison of the visual outcomes between PRK-MMC and phakic IOL implantation in high myopic patients

Purpose

To compare the visual outcomes between PRK-MMC and phakic IOL in patients with more than 8 diopter (D) of myopia.

Methods

This comparative study was performed on 23 eyes under treatment with Artiflex (group A) and 23 eyes under treatment with PRK-MMC (group B). Artiflex phakic IOL (Ophtec BV) was used in group A, and the VISX STAR S4 Excimer Laser (Abbott) was used for PRK-MMC in group B.

Results

The safety index was 1.11±0.23 and 1.05±0.25 (P=0.100) and the efficacy index was 1.02±0.11 and 0.98±0.10 (P=0.266) in group A and B, respectively. At 1 year after surgery, the manifest refraction spherical equivalent was −0.17±1.18 and −0.25±0.18 D in group A and B, respectively (P=0.471). Mesopic CS showed no significant difference between the two groups in any spatial frequency. Total coma was 0.24±0.17 and 0.67±0.40 μm (P<0.001), spherical aberration was −0.11±0.11 and 0.41±0.18 μm (P<0.001), and RMS HOA_T was 0.50±0.20 and 0.96±0.45 μm (P<0.001) in group A and B, respectively.

Conclusion

Phakic IOL implantation was better than PRK-MMC in the correction of high myopia in terms of visual quality, but the two methods had no difference with regard to visual acuity. Therefore, PRK-MMC can be used when the anterior chamber depth is a limiting factor in the implantation of phakic IOLs.     

Intra-ocular lens power calculation in patients with high axial myopia before cataract surgery

Purpose

To evaluate the accuracy of different formulas used for IOL power calculation in patients with high axial myopia undergoing cataract surgery.

Methods

A prospective clinical study was carried out on 53 eyes of 51 patients with an axial length from 25.5 to 31.4 mm including 21 males (41.2%) and 30 females (58.8%). Calculation of the IOL power to be implanted was done by three available IOL power formulas; Haigis formula, SRK/T formula, and Holladay I formula. The mean error (ME) was calculated from the difference between the formula predicted refractive error and the actual post operative refractive error.

Results

There was no statistically significant difference between the mean error of the three formulas used in the overall performance or in the axial length subcategories. SRK/T formula caused the smallest mean error, (+0.17 D). Haigis formula showed a higher ME (+0.21 D) and Holladay formula caused a myopic postoperative refractive error (−0.20 D).

Conclusion

The calculation of IOL power in patients with high axial myopia using the third or the fourth generation formulas help in improvement of the accuracy of the calculation and decreasing the post operative refractive error. SRK/T formula showed the lowest mean error, however, there was not statistically significant difference between the three formulas used, neither in the overall performance, nor in axial length subcategories.     

Lens thickness assessment: anterior segment optical coherence tomography versus A-scan ultrasonography

AIM: To assess lens thickness measurements with anterior segment-optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US). METHODS: There were 218 adult subjects (218 eyes) aged 59.2±9.2y enrolled in this prospective cross-sectional study. Forty-three eyes had open angles and 175 eyes had narrow angles. Routine ophthalmic exam was performed and nuclear opacity was graded using the Lens Opacities Classification System III (LOCS III). Lens thickness was measured by AS-OCT (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA). The highest quality image was selected for each eye and lens thickness was calculated using ImageJ software. Lens thickness was also measured by A-scan US. RESULTS: Interclass correlations showed a value of 99.7% for intra-visit measurements and 95.3% for inter-visit measurements. The mean lens thickness measured by AS-OCT was not significantly different from that of A-scan US (4.861±0.404 vs 4.866±0.351 mm, P=0.74). Lens thickness values obtained from the two instruments were highly correlated overall (Pearson correlation coefficient=0.81, P<0.001), and in all LOCS III specific subgroups except in grade 5 of nuclear opacity. Bland-Altman analysis revealed a 95% limit of agreement from -0.45 to 0.46 mm. Lens thickness difference between the two instruments became smaller as the lens thickness increased and AS-OCT yielded smaller values than A-scan US in thicker lens (β=-0.29, P<0.001) CONCLUSION: AS-OCT-derived lens thickness measurement is valid and comparable to the results obtained by A-scan US. It can be used as a reliable noncontact method for measuring lens thickness in adults with or without significant cataract.     

Combined 23-gauge microincisonal vitrectomy surgery and phacoemulsification with AcrySof toric intraocular lens implantation: a comparative study

Aim

To compare AcrySof toric intraocular lens (IOL) and non-toric IOL in patients who had combined 23-gauge microincisional vitrectomy surgery (MIVS) and phacoemulsification for vitreoretinal diseases and cataract with pre-existing corneal astigmatism.

Methods

This is a prospective comparative study comprised of 30 patients (30 eyes) who had combined 23-gauge MIVS and phacoemulsification for vitreoretinal diseases and cataract with pre-existing regular corneal astigmatism greater than 1 diopters (D). In all, 15 eyes had AcrySof toric IOL (Alcon Laboratories) and 15 eyes had non-toric IOL (Akreos AO MI60; Bausch & Lomb) implantation. Main outcome measures were uncorrected visual acuity (UCVA), refractive cylinder, surgically induced astigmatism (SIA), and IOL misalignment during 6 months.

Results

The mean UCVA of the toric IOL group was better than the non-toric IOL group at postoperative months 1, 3, and 6 (P<0.001, respectively). The mean absolute residual refractive cylinder of the toric IOL group at postoperative week 1, and months 1, 3, and 6 was less than the non-toric IOL group (P=0.008, <0.001, <0.001, and <0.001, respectively). There was no difference in the mean SIA between the two groups (P>0.05, respectively). The mean toric IOL axis rotation was 3.52±2.75°, which was within 5° in 66.7% of the toric IOL group and within 10° in 100%.

Conclusions

Combined 23-gauge MIVS and phacoemulsification with AcrySof toric IOL implantation is an effective method of correcting vitreoretinal diseases and cataract and pre-existing corneal astigmatism, and the toric IOL showed good rotational stability, even in vitrectomized eyes for 6 months.     

Comparision of surgical outcomes of intraocular lens refixation and intraocular lens exchange with perfluorocarbon liquid and fibrin glue-assisted sutureless scleral fixation

Aim

The purpose of this study was to compare the surgical outcomes of intraocular lens (IOL) refixation with intraocular lens exchange using perfluorocarbon liquid (PFCL) and fibrin glue-assisted sutureless scleral fixation surgery in patients with dislocation of the IOL.

Methods

Twenty-five eyes of 25 patients who underwent surgery for dislocated IOLs with PFCL and fibrin glue-assisted scleral fixation were studied; 13 eyes experienced IOL refixation (in-the-bag and out-of-the-bag), and 12 eyes experienced IOL exchange. Preoperative and postoperative clinical features from patient charts and 25 eyes with >6 months'' follow-up information were reviewed and analyzed.

Results

At postoperative 6 months, best-corrected visual acuity (BCVA) and spherical equivalent of IOL refixation and exchange were significantly improved (P=0.042, P=0.001), and endothelial cell density was significantly decreased in the two groups with no significant difference between them. Surgically induced astigmatism of IOL refixation improved from 0.90±0.47 to 0.61±0.37 (P=0.012), and IOL exchange improved from 1.17±0.64 to 0.73±0.37 (P=0.037) at postoperative 6 months, with no significant difference between the two groups. Complications occurred in four eyes in the IOL refixation group and in three eyes in the IOL exchange group.

Conclusion

PFCL and fibrin glue-assisted IOL sutureless scleral refixation or exchanged fixation was an effective surgical treatment for IOL dislocation. Also, because postoperative BCVA, surgical outcomes, and complications did not differ significantly between IOL refixation and exchange surgery, if IOL exchange surgery is not indicated, IOL refixation surgical techniques should be considered.     

Long-Term Efficacy and Rotational Stability of AcrySof Toric Intraocular Lens Implantation in Cataract Surgery

Purpose

To evaluate the long-term efficacy and rotational stability of the AcrySof toric intraocular lens (IOL) in correcting preoperative astigmatism in cataract patients.

Methods

This prospective observational study included 30 eyes from 24 consecutive patients who underwent implantation of an AcrySof toric IOL with micro-coaxial cataract surgery between May 2008 and September 2008. Outcomes of visual acuity, refractive and keratometric astigmatism, and IOL rotation after 1 day, 1 month, 3 months, and long-term (mean, 13.3±5.0 months) follow-up were evaluated.

Results

At final follow-up, 73.3% of eyes showed an uncorrected visual acuity of 20/25 or better. The postoperative keratometric value was not different from the preoperative value; mean refractive astigmatism was reduced to -0.28±0.38 diopter (D) from -1.28±0.48 D. The mean rotation of the toric IOL was 3.45±3.39 degrees at final follow-up. One eye (3.3%) exhibited IOL rotation of 10.3 degrees, the remaining eyes (96.7%) had IOL rotation of less than 10 degrees.

Conclusions

Early postoperative and long-term follow-up showed that implantation of the AcrySof toric IOL is an effective, safe, and predictable method for managing corneal astigmatism in cataract patients.     

The association of vitamin D deficiency with tear break-up time and Schirmer testing in non-Sj?gren dry eye

Purpose

To investigate the effect of vitamin D deficiency on tear break-up time (TBUT) and Schirmer test scores and to assess their relationship in non-Sjögren dry-eye patients.

Methods

Thirty-four patients with serum vitamin D deficiency and 21 control subjects with normal vitamin D levels were included in this study. The TBUT and Schirmer-1 test without topical anesthesia were performed to all patients.

Results

The mean TBUT were 5.18±2.15 and 7.36±3.10 s and Schirmer scores were 12.18±6.44 and 18.57±8.99 mm in the study and control groups, respectively. TBUT scores and Schirmer-1 results of the study group were significantly lower than the control group (P=0.01 and 0.007, respectively). The mean vitamin D levels were 11.50±1.8 ng/ml in the study group and 32.8±8.72 ng/ml in control group (P=0.001). Dry-eye symptoms were detected in all patients in the study group and 15% of the patients in the control group.

Conclusions

We demonstrated that vitamin D deficiency decreases the TBUT and Schirmer test values and may be associated with dry-eye symptoms in non-Sjögren syndrome.     

Biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy

Purpose

To determine the biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy (TAO).

Methods

Retrospective, observational study (between October 2012 and September 2014) was performed. Patients with TAO undergoing orbital decompression for stable proptosis received ophthalmic examinations, including Hertel exophthalmometry, A-scan biometry, autorefraction measures, corneal topography, and wavefront aberration measures, before orbital decompression and again 2 months after surgery.

Results

Included in the study were 43 eyes from 23 patients. The mean exophthalmometric value decreased by 4.1 mm 2 months after orbital decompression (P<0.001). On average, axial length (AL) increased significantly by 0.08 mm (P<0.001); specifically, 37 (86%) of the 43 eyes had increased AL. Whereas anterior chamber depth and lens thickness showed no significant changes (P=0.086 and P=0.905, respectively), the mean spherical refraction and spherical equivalent (SE) decreased by 0.35 and 0.48 D, respectively (P=0.008 and P<0.001, respectively). However, cylindrical refraction and axis showed no significant changes (P=0.057 and P=0.218, respectively). The changes in AL and SE were significantly correlated (R=−0.411, P=0.009). Notably, there were no changes in corneal topography or wavefront aberration after orbital decompression.

Conclusions

TAO patients who underwent orbital decompression showed myopic refractive change via increase in AL. Possible refractive changes should be considered in cases of TAO complaining of decreased visual acuity after orbital decompression.     

Ocular residual astigmatism's effect on high myopic astigmatism LASIK surgery

Purpose

To analyze the effect of ocular residual astigmatism (ORA) on the effectiveness of LASIK for treating high myopic astigmatism.

Methods

This is an observational, cross-sectional study. We studied 116 consecutive myopic eyes with −3 diopters (D) or more of astigmatism that underwent LASIK surgery. The magnitude of uncorrected residual refractive astigmatism 3 months postoperatively was measured.

Results

The mean preoperative cylinder was −4.0±0.83 D (range, −7.5 to −3 D) and the mean preoperative ORA was 0.82±0.5 D. The mean residual refractive cylinder 3 months postoperatively was −0.78±0.83 D (range, −3 to 0 D). No correlation was found between ORA and the refractive cylinder 3 months postoperatively (P=0.6).

Conclusion

In eyes with high myopic astigmatism undergoing LASIK, ORA was not correlated with the residual postoperative cylinder.     

Retinal nerve fiber layer and optic disc measurements by spectral domain OCT: normative values and associations in young adults

Purpose

To determine normative values and associations of retinal nerve fiber layer (RNFL) and optic disc parameters in normal eyes measured by spectral domain optical coherence tomography (OCT).

Methods

In a population-based setting, 1521 young adults were examined as part of the Sydney Adolescent Vascular and Eye Study (SAVES). Their mean age was 17.3±0.6 years. RNFL and optic disc parameter measurements were made using Cirrus HD-OCT 4000.

Results

The average RNFL was found to be 99.4±9.6 μm. RNFL thickness was least for the temporal quadrant (69.9±11.2 μm), followed by the nasal (74.3±12.8 μm), superior (124.7±15.7 μm) and inferior (128.8±17.1 μm) quadrants. The mean disc area in this population was 1.98±0.38 mm² with a mean rim area of 1.50±0.30 mm² and a mean cup/disc ratio of 0.44±0.18. Multivariate-adjusted RNFL thickness was marginally greater in East Asian than in white participants (100.1 μm vs 99.5 μm; P=0.0005). The RNFL was thinner with greater axial length (P<0.0001), less positive spherical equivalent refractions (P<0.0001), smaller disc area and rim area (P<0.0001).

Conclusion

This study documents normative values for the RNFL and optic disc measured using Cirrus HD-OCT in young adults. The values and associations reported in this study can inform clinicians on the normal variation in RNFL and optic disc parameters.     

The Correlation between Angle Kappa and Ocular Biometry in Koreans

Purpose

To investigate normative angle kappa data and to examine whether correlations exist between angle kappa and ocular biometric measurements (e.g., refractive error, axial length) and demographic features in Koreans.

Methods

Data from 436 eyes (213 males and 223 females) were analyzed in this study. The angle kappa was measured using Orbscan II. We used ocular biometric measurements, including refractive spherical equivalent, interpupillary distance and axial length, to investigate the correlations between angle kappa and ocular biometry. The IOL Master ver. 5.02 was used to obtain axial length.

Results

The mean patient age was 57.5 ± 12.0 years in males and 59.4 ± 12.4 years in females (p = 0.11). Angle kappa averaged 4.70 ± 2.70 degrees in men and 4.89 ± 2.14 degrees in women (p = 0.48). Axial length and spherical equivalent were correlated with angle kappa (r = -0.342 and r = 0.197, respectively). The correlation between axial length and spherical equivalent had a negative correlation (r = -0.540, p < 0.001).

Conclusions

Angle kappa increased with spherical equivalent and age. Thus, careful manipulation should be considered in older and hyperopic patients when planning refractive or strabismus surgery.     

Corneal changes after a single session of selective laser trabeculoplasty for open-angle glaucoma

Purpose

To investigate the changes in endothelial cell count, central corneal thickness (CCT), and refractive error after a session of selective laser trabeculoplasty (SLT) for open angle glaucoma (OAG).

Methods

This prospective cohort study recruited 111 eyes of 66 consecutive subjects with OAG. Subjects received SLT to 360° of the trabecular meshwork. Endothelial cell count, CCT, and spherical equivalent were measured at baseline before SLT as well as at 1 week and 1 month post SLT. A repeated measure nested ANOVA with Tukey''s multiple comparison test was performed to compare the outcome measures before and after SLT.

Results

In 111 eyes of 66 subjects, the mean number of laser applications per treatment was 166.9±41.4 with a mean energy level of 1.0±0.07 mJ. The mean endothelial cell count decreased significantly from 2465.0±334.0 cells/mm² at baseline to 2355.0±387.0 cells/mm² at 1 week (P=0.0004) but increased to baseline levels at 1 month post SLT (2424.0±379.4 cells/mm², P=0.3). The CCT, which decreased from a baseline of 549.4±37.6 to 543.9±40.2 μm at 1 week post SLT (P=0.02), also returned to the baseline level by 1 month (P=0.2). The spherical equivalent was static from baseline. A positive correlation was found between total laser energy and CCT at 1 month post treatment (r=0.3, P=0.005).

Conclusion

The transient reductions in endothelial cell count and CCT following SLT returned to baseline levels 1 month after the procedure. Patients undergoing SLT should be aware of the risk of potential corneal changes.