Lan-Hsin Chuang

Choroidal Thickness and Biometric Markers for the Screening of Lacquer Cracks in Patients with High Myopia

Objectives Validation of choroidal thickness and other biometrics measured by spectral domain optical coherence tomography (SD-OCT) in predicting lacquer cracks formation in highly myopic eyes. Methods Patients with a refractive error worse than −8 diopters and moderate myopic maculopathy were recruited into two groups based on the presence or absence of lacquer cracks (36 eyes without and 33 eyes with lacquer cracks). Choroidal thickness, refractive error, and axial length were measured and subjected to receiver operating characteristic curve analysis to identify the optimal cutoff values at predicting lacquer crack formation. The width of the retinal pigment epithelium (RPE), RPE to the inner segment/outer segment line, RPE to the external limiting membrane were also measured and compared to the subfoveal choroidal thickness to assess their relationships as potential markers of lacquer crack formation. Results Lacquer crack is associated with decreased choroidal thickness, lower best-corrected visual acuity, longer axial length and higher refractive errors. Choroidal thickness has the strongest association with lacquer crack formation versus axial length and refractive error. In eyes with lacquer cracks, stellate lacquer cracks are associated with thinner choroidal thickness compared to eyes with linear lacquer cracks. Subfoveal choroidal thickness less than the width of the retinal pigment epithelium to the inner segment/outer segment line is also associated with lacquer crack formation (sensitivity 78.8%, specificity 88.3%, and accuracy 81.2%). Conclusions This study suggests that choroidal thickness and other SD-OCT measurements could be employed clinically to predict the development and severity of lacquer cracks in patients with high myopia.

Classification of Early Dry-Type Myopic Maculopathy with Macular Choroidal Thickness

PURPOSE To compare the macular choroidal thickness in 2 types of early dry-type myopic maculopathy. DESIGN Prospective, observational, comparative study. METHODS Patients with a refractive error of less than -8 diopters were included and were classified into 2 groups. Group 1 consisted of 24 eyes with a tessellated fundus, and group 2 consisted of 33 eyes with diffuse chorioretinal atrophy, but not to the extent of patchy chorioretinal atrophy. These 2 groups were compared with regard to their clinical characteristics, refractive error, axial length, macular choroidal thickness, and best-corrected visual acuity (BCVA). Linear regression was used to evaluate the explanatory variables in terms of macular choroidal thickness and BCVA. RESULTS Patients in group 1 were significantly younger and had better BCVA, less myopia, shorter axial length, and less staphyloma than those in group 2. Refractive error, axial length, and BCVA correlated significantly with macular choroidal thickness in group 2. However, no such significant correlations were observed in group 1. Multiple linear regression analysis showed that age and macular choroidal thickness were the variables that associated most strongly with BCVA, whereas neither refractive error nor axial length was a significant predictor of BCVA. In group 2, eyes with lacquer cracks showed worse BCVA and thinner macular choroidal thickness than eyes without lacquer cracks. CONCLUSIONS Macular choroidal thickness is an important factor in myopic maculopathy and can be a better indicator of its severity. These findings suggest that BCVA reduction in eyes with dry-type myopic maculopathy can be related to a thinner macular choroidal thickness and to the development of lacquer cracks.

Secondary Ocular Hypertension After Intravitreal Injection with 2 mg or 4 mg of Triamcinolone in Retinal Vein Occlusion

PURPOSE To evaluate secondary ocular hypertension after intravitreal injection of triamcinolone acetonide (IVTA) with 2 mg/0.05 mL or 4 mg/0.1 mL for macular edema associated with retinal vein occlusion (RVO). METHODS A retrospective chart review was performed. Patients with RVO, including central RVO and branch RVO, were divided into 2 groups. Group 1 was patients who received 2 mg IVTA and group 2 received 4 mg IVTA. The dose of IVTA was dependent on individual surgeons decision. Secondary ocular hypertension was defined as intraocular pressure (IOP) >21 mmHg. Long-term antiglaucoma medication referred to eyes that required antiglaucoma agents for >6 months. RESULTS Thirty-six eyes in group 1 and 32 eyes in group 2 were included in the analyses. The mean age of all the patients was 58.6 years, and 52.9% of patients were men. The mean follow-up period was 12.4 months. A wide range (from day 7 to month 8) of time until the onset of the IOP spike was recorded after the injection. The incidence of secondary ocular hypertension was not significantly different between group 2 and group 1 (38.9% vs. 50%, P = 0.36). However, group 2 had a higher proportion of long-term antiglaucoma medication usage than group 1 (5.6% vs. 40.6%; Pearson chi-square, P < 0.001). Ultimately, 2.9% of patients underwent filtration surgery. Macular edema diminished and best-corrected visual acuity improved at 3 months later in both groups. CONCLUSIONS With a similar effect on vision recovery and alleviating macular edema associated with RVO, 2 mg IVTA required a shorter duration of medical control for secondary ocular hypertension than 4 mg IVTA.

Serum concentration of bevacizumab after intravitreal injection in experimental branch retinal vein occlusion.

Aim: To compare the serum concentration of bevacizumab after intravitreal injection of bevacizumab (IVB) in an experimental model of branch retinal vein occlusion (BRVO) with control injections in albino rats. Methods: BRVO was created in one eye of each of the 24 albino rats. Another 24 rats served as controls. The BRVO was generated by argon laser photothrombosis after intravenous injection with Rose Bengal. Three days later, IVB (5 µl) was administered to both BRVO and control eyes. The serum concentration of bevacizumab was examined at baseline, 6 h, 1 day, 3 days, 7 days, 14 days, and 28 days after IVB. Results: At baseline, no serum bevacizumab was detected in either group. The serum concentration of bevacizumab reached a peak concentration at 1 day with 5,020 ± 1,602 ng/ml in the BRVO group and 4,103 ± 1,790 ng/ml in the control group (p < 0.001). The concentration decreased subsequently on days 3, 7, 14 and 28. The serum concentration of bevacizumab was significantly higher in BRVO rats up to 28 days after IVB. Conclusions: The serum concentration of bevacizumab after IVB reached its peak on day 1 in both BRVO and control eyes. This value was significantly higher in BRVO rats than in control rats up to 28 days after intravitreal injection.

Associations between chronic glycosylated haemoglobin (HbA1c) level and macular volume in diabetes patients without macular oedema

Acta Ophthalmol. 2010: 88: 753–758

Outcomes of Outpatient Fluid-Gas Exchange for Open Macular Hole After Vitrectomy

PURPOSE To report the efficacy and safety of outpatient fluid-gas exchange for open macular hole after primary vitrectomy. DESIGN Retrospective interventional case series. METHODS setting: Institutional. patients: Thirty-six patients with primary failed closure or reopened holes after primary vitrectomy. intervention: Fluid-gas excahnge with 15% perfluoropropane (C3F8) or 20% sulfur hexafluoride (SF6) was performed to reclose the hole under topical anesthesia. main outcome measures: The hole closure rate and type, pre- and postexchange best-corrected visual acuity (BCVA), and complication rates were assessed. RESULTS Thirty-two eyes (89%) achieved anatomic success from 1-3 weeks after the fluid-gas exchange. Twenty-two eyes (61%) achieved type 1 closure, 10 eyes (28%) achieved type 2 closure, and 4 eyes (11%) did not achieve closure. The BCVA for type 1 closure improved significantly from logarithm of the minimal angle of resolution (logMAR) 1.66 ± 0.41 to 0.84 ± 0.41, with a P value <.001. The BCVA for type 2 closure improved from logMAR 1.77 ± 0.41 to 1.52 ± 0.41, with a P value of .05. All patients with an unclosed hole after fluid-gas exchange had a stage IV macular hole before the primary vitrectomy and a hole size larger than 1000 μm. The complication related to fluid-gas exchange procedure was transient high intraocular pressure, which responded well to topical antiglaucoma medications. There were 2 retinal detachment cases following the exchange; surgery to reattach the retina was performed, with visual acuity recovery. CONCLUSION Outpatient fluid-gas exchange is an effective treatment option for eyes with open holes following vitrectomy.

The long-term anatomical and visual effect of intravitreal triamcinolone injection during vitrectomy for the treatment of idiopathic macular epiretinal membrane.

Purpose: To compare the long-term anatomical and visual outcomes of patients with idiopathic epiretinal membrane (ERM) removed by vitrectomy and membrane peeling with or without the use of intravitreal injection of triamcinolone acetonide (IVTA). Methods: A retrospective chart review was performed. Subjects who underwent vitrectomy and who were followed over 12 months were included. The study included two groups of patients. In group 1 (71 eyes), the patients underwent vitrectomy and membrane peeling without the use of IVTA. In group 2 (27 eyes), 2 mg of IVTA was given at the end of the surgery. The main outcome measures were best-corrected visual acuity (BCVA), central foveal thickness (CFT) determined by optical coherence tomography (OCT), the number of cataract surgeries, and the use of anti-glaucomatous drugs during the follow-up period. Results: This study included 98 eyes with ERM from 98 patients. There was no significant difference between the two groups with respect to age, gender, pre- and postoperative lens status, BCVA, CFT, or length of the follow-up period. The mean age for all of the patients was 62.45 ± 10.01 (mean ± SD) years, and the mean follow-up length was 20.58 ± 9.64 (mean ± SD) months. In all cases, the mean best-corrected logarithm of minimum angle of resolution (logMAR) acuity improved from a preoperative value of 0.91 ± 0.32 [Snellen equivalent (SE), 0.16 ± 0.14] to a postoperative value of 0.46 ± 0.36 (SE, 0.46 ± 0.29) (P < 0.0001). The CFT was reduced from a preoperative value of 473.46 ± 96.91 μm to a postoperative value of 302.44 ± 69.80 μm (P < 0.0001). Six patients (22.2%) in group 2 required anti-glaucomatous drugs to control intraocular pressure (IOP) during the follow-up period, and three patients (4.2%) in group 1 required drugs to control IOP (P = 0.012). Conclusions: The postoperative visual outcomes for patients with idiopathic ERM were favorable, but CFT did not return to a normal level, even in eyes in which 2 mg IVTA was used. The IVTA use after ERM removal produced no significant benefits during long-term follow-up, but IVTA did increase the risk of increased IOP.

Vitrectomy and panretinal photocoagulation reduces the occurrence of neovascular glaucoma in central retinal vein occlusion with vitreous hemorrhage.

Purpose: The purpose of this study was to evaluate the best-corrected visual acuity and occurrence of neovascular glaucoma with vitrectomy (VT) and panretinal photocoagulation or without VT in central retinal vein occlusion (CRVO) associated with vitreous hemorrhage (VH). Methods: The charts from patients diagnosed as having CRVO with VH at Chang Gung Memorial Hospital (Taiwan) were reviewed. They were grouped based on whether they also underwent VT. The main outcome measurements were the best-corrected visual acuity and incidence of neovascular glaucoma. Results: There were 83 eyes that had CRVO with VH from 83 patients (VT group, 56 eyes; non-VT group, 27 eyes). There was no significant difference between the VT and non-VT groups in terms of age, gender, diabetes, hypertension, lens status, and follow-up period. The non-VT group had a better best-corrected visual acuity (P = 0.018) and less VH (P = 0.025) than the VT group at baseline; however, the VT group had a better best-corrected visual acuity at the end of the follow-up than the non-VT group (P < 0.001). Most importantly, there was a higher neovascular glaucoma development (37%) in the non-VT group compared with that (14.3%) in the VT group (P = 0.025). Conclusion: The visual outcomes of CRVO with VH are unfavorable whether VT was performed. However, VT and panretinal photocoagulation improved visual acuity and reduced the incidence of neovascular glaucoma in CRVO with VH.

Macular hole repair by vitrectomy and internal limiting membrane peeling in highly myopic eyes.

Purpose: To evaluate the surgical outcomes of macular hole (MH) repair by vitrectomy and internal limiting membrane peeling in highly myopic eyes. Methods: In this retrospective interventional case series, 30 highly myopic eyes with MH in 29 consecutive patients who underwent vitrectomy and internal limiting membrane peeling to repair MH were studied. The mean follow-up time was 36.4 months. The anatomical outcomes of the MH were evaluated by optical coherence tomography. The best-corrected visual acuities before and after surgery were compared as the functional outcome. Results: Women accounted for 69% of MH in highly myopic eyes. The mean age was 49 years. The mean refraction error and mean axial length were −9.80 (±2.93) diopter and 28.13 (±2.41) mm, respectively. Myopic foveoschisis was observed in 3 eyes (10%). The MHs were closed by a single surgery in 26 eyes (87%), and the final closure rate was 97% (29/30 eyes). Macular hole surgery significantly improved best-corrected visual acuity from 1.20 ± 0.70 to 0.77 ± 0.51 logarithm of the minimum angle of resolution (P = 0.003). However, rhegmatogenous retinal detachment developed in 3 eyes (10%) during the follow-up. Conclusion: Vitrectomy with internal limiting membrane peeling is effective to repair MH in highly myopic eyes in terms of anatomical and functional outcomes, although visual acuity may continue to improve slowly until 3 years after successful MH-closing surgery. In addition, a small proportion of MH cases were associated with myopic foveoschisis. Delayed hole closure and rhegmatogenous retinal detachment may occur in these highly myopic eyes after surgery.

Axial length and proliferative diabetic retinopathy.

Purpose. To determine the correlation between axial length and diabetic retinopathy (DR) in patients with diabetes mellitus for 10 years or more. Methods. This study was a prospective, observational, cross-sectional study. Patients with diabetes for 10 years or more were included. We excluded eyes with any other significant ocular disease or any prior intraocular surgery, except uncomplicated cataract surgery. Only one eye of each patient was included as the study eye. The severity of DR was graded as no DR, non-proliferative DR (NPDR), or proliferative DR (PDR). Axial length was measured by A-scan ultrasound (10 MHz Transducer, AL-2000 Biometer/Pachymeter; Tomey, Phoenix, AZ). Univariate logistic regression models were used to evaluate the relationship between the dependent variables (any DR, PDR) and all potential risk factors. Axial length and other factors with p value <0.1 were included in multivariate logistic regression models. Backward selection based on the likelihood ratio statistic was used to select the final models. Results. We included 166 eyes from 166 patients (93 female and 73 male; mean age, 68.8 years). The mean diabetes duration was 15.4 years. Fifty-four (32.5%) eyes had no DR, 72 (43.4%) eyes had NPDR, and 40 (24.1%) eyes had PDR. In univariate analysis, hypertension (p = 0.009), renal impairment (p = 0.079), and insulin use (p = 0.009) were associated with developing any DR. Hypertension (p = 0.042), renal impairment (p = 0.014), insulin use (p = 0.040), pseudophakia (p = 0.019), and axial length (p = 0.076) were associated with developing PDR. In multivariate analysis, hypertension (p = 0.005) and insulin use (p = 0.010) were associated with developing any DR. Hypertension (p = 0.020), renal impairment (p = 0.025), pseudophakia (p = 0.006), and axial length (p = 0.024) were associated with developing PDR. Conclusions. This observational study suggests an inverse relationship between axial length and the development of PDR in patients with diabetes for 10 years or more. No relationship was found between axial length and the development of any DR.