Author: Ophthalmology

Functional Improvement after One- and Two-Eye Cataract Surgery in the Salisbury Eye Evaluation

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Purpose:
To determine the impact that cataract and cataract surgery have on clinical measurements of vision, reading speed, objective mobility performance, and subjective visual functioning.

Design:
Prospective, population-based study.

Participants:
A total of 1739 Salisbury Eye Evaluation (SEE) participants without previous cataract surgery with bilateral baseline best-corrected visual acuity (BCVA) of logarithm of the minimum angle of resolution (logMAR) ≤0.3 (≥20/40) or cataract surgery between rounds 1 and 2.

Methods:
Participants were categorized on the basis of cataract surgery by round 2 into no surgery, unilateral surgery, or bilateral surgery. Visual performance, mobility-based tasks, and the Activities of Daily Vision Scale (ADVS) were measured at baseline and 2 years. Mobility score was converted into a z score by subtracting the participant’s time from the population baseline average and then dividing by the standard deviation. Comparisons were made between the no surgery and surgery groups using multivariate linear regression.

Main Outcome Measures:
Change in bilateral BCVA in logMAR, contrast sensitivity, reading speed in words per minute (wpm), mobility score, and ADVS.

Results:
During the study period, 29 participants had cataract surgery on both eyes, 90 participants had unilateral surgery, and 1620 participants had no surgery. After adjusting for baseline value, demographics, depression, and mental status, the unilateral surgery group’s BCVA improved 0.04 logMAR (P = 0.001) and the bilateral group’s BCVA improved 0.13 compared with no surgery (P<0.001). Overall mobility declined in all groups. The unilateral group’s z score decreased 0.18 more than that of the no surgery group (P = 0.02), whereas the bilateral group showed a 0.18 z score improvement compared with no surgery (P = 0.19). Change in reading speed significantly improved in the unilateral and bilateral groups compared with no surgery (12 and 31 wpm, respectively). The bilateral surgery group showed significant positive change in ADVS compared with no surgery (5 points of relative improvement; P = 0.01), whereas the unilateral group showed a 5-point relative decline (P<0.001).

Conclusions:
Cataract negatively affects both subjective quality of life and objective performance measures. Unilateral cataract surgery improves visual functioning, but the largest gains are found in patients who undergo second-eye cataract surgery. This finding supports second-eye cataract surgery for patients with visual or functional symptoms even after successful first-eye surgery.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Seasonal Changes in Visual Field Sensitivity and Intraocular Pressure in the Ocular Hypertension Treatment Study

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Purpose:
Longitudinal testing plays a key role in glaucoma management. Variability between visits hampers the ability to monitor progression. It has previously been shown that average intraocular pressure (IOP) exhibits seasonal fluctuations. This study examines whether visual field sensitivity also exhibits seasonal fluctuations and seeks to determine whether such fluctuations are correlated to seasonal IOP effects.

Design:
Comparative case series.

Participants:
A total of 33 873 visits by 1636 participants enrolled in the Ocular Hypertension Treatment Study. Participants were split into 6 geographic zones according to the prevailing climate in their location.

Testing:
At each visit, standard automated perimetry was conducted on each eye, and IOP was measured.

Main Outcome Measures:
Mixed effects regression models were formed to look for sinusoidal periodic effects on the change in perimetric mean deviation since the last visit (ΔMD) and on IOP, both overall and within each zone.

Results:
When all the data were included, a significant seasonal effect on ΔMD was found with magnitude 0.06 dB, peaking in February (P < 0.001). Five of the 6 geographic zones exhibited significant seasonal effects on ΔMD, peaking between January and April, with magnitudes ranging from 0.04 dB (P = 0.049) to 0.21 dB (P < 0.001). Zones with greater climactic variation showed larger seasonal effects on ΔMD. All 6 zones exhibited a seasonal effect on IOP, peaking in January or February, with magnitudes ranging from 0.14 to 0.39 mmHg (P ≤ 0.02 in all cases). However, there was no evidence of a significant association between the magnitudes or dates of peaks of the 2 seasonal effects.

Conclusions:
The mean deviation was significantly higher in winter than in summer. There is no evidence of an association with seasonal IOP fluctuations. The cause of the seasonal effect on visual field sensitivity is unknown. These findings may help shed light on the glaucomatous disease process and aid efforts to reduce test–retest variability.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Progression of Intermediate Age-related Macular Degeneration with Proliferation and Inner Retinal Migration of Hyperreflective Foci

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Purpose:
Drusen and migrating retinal pigment epithelium have been associated with hyperreflective foci (HF) detected by spectral-domain optical coherence tomography (SD-OCT). This study sought to quantify the change in intraretinal HF distribution and its correlation with age-related macular degeneration (AMD) disease progression.

Design:
Prospective observational study from the multicenter Age-Related Eye Disease Study 2 (AREDS2) Ancillary SD-OCT Study.

Participants:
Patients (n=299) with 1 enrolled eye with intermediate AMD and baseline SD-OCT, followed by SD-OCT imaging at 1-year and 2-year visits.

Methods:
The number and location of HF were scored in SD-OCT scans of all 299 eyes. The change in transverse (horizontal) and axial (vertical) distribution of HF in the macula were evaluated with pairwise signed-rank tests. Two-year inner retinal HF migration was determined by the change in HF-weighted axial distribution (AxD) score calculated for each eye. The correlation of HF with SD-OCT features of AMD progression was evaluated with logistic regression analysis.

Main Outcome Measures:
The mean change in number of HF, transverse and axial distribution of HF in the macula, and AxD per eye.

Results:
In 299 study eyes, the 2-year increase in the number of HF (P<0.001) and the AxD (P<0.001) per eye represented longitudinal proliferation and shift to inner retinal layers, respectively. Eyes with geographic atrophy (GA) at 2 years were correlated with the presence of baseline HF (P<0.001; odds ratio [OR], 4.72; 95% confidence interval [CI], 2.43–9.80), greater number of baseline HF (P<0.001; OR, 1.61 per HF; 95% CI, 1.32–2.00), and greater baseline AxD (P<0.001; OR, 1.58 per AxD point; 95% CI, 1.29–1.95).

Conclusions:
Proliferation and inner retinal migration of SD-OCT HF occurred during follow-up in eyes with intermediate AMD. These characteristics were associated with greater incidence of GA at year 2; therefore, SD-OCT HF proliferation and migration may serve as biomarkers for AMD progression.

Financial Disclosure(s):
Proprietary or commercial disclosure may be found after the references.

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Spectral-Domain Optical Coherence Tomographic Assessment of Schlemm’s Canal in Chinese Subjects with Primary Open-angle Glaucoma

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Purpose:
To evaluate in vivo features of Schlemm’s canal (SC) in patients with primary open-angle glaucoma (POAG) with spectral-domain optical coherence tomography (SD-OCT) and to investigate the relationship of SC size with intraocular pressure (IOP) and glaucoma severity.

Design:
Prospective, comparative study.

Participants:
Fifty Chinese patients with newly diagnosed POAG who had not undergone surgery and 50 normal Chinese subjects from a population-based, cross-sectional study in Shanghai.

Methods:
All participants underwent SD-OCT. The diameter and area of SC were examined in the temporal and nasal sections and measured with customized software.

Main Outcome Measures:
Patient demographics, repeatability and reproducibility assessed with the coefficient of variation (CV) and the intraclass correlation coefficient (ICC), SC parameters and their correlation with IOP, and the mean deviation (MD) of the visual field were analyzed.

Results:
The percentage of sections in which SC was observable was similar between eyes with POAG and normal eyes, and ranged from 78% to 86%. For intraobserver repeatability, the CV and ICC values were 7.9% and 0.97 for diameter, and 13.8% and 0.83 for area, respectively. For interobserver repeatability, the CV and ICC values were 13.6% and 0.89 for diameter, and 13.4% and 0.80 for area, respectively. Significant differences between the 2 groups were found for the average SC area (11332±2015 μm2 vs. 13991±1357 μm2; P<0.001), but not for the SC diameter (40.2±7.1 μm vs. 45.2±4.0 μm; P = 0.195). In addition, the mean IOP values correlated well only with the SC area (ρ = −0.674, P<0.001), not with the SC diameter (ρ = −0.103, P = 248). No significant correlations were found between the MD values and the SC parameters.

Conclusions:
Eyes with POAG have a decreased SC area compared with normal eyes. A correlation between the SC area and the IOP also was observed. However, the degree of glaucoma damage was not consistently associated with the SC area. Spectral-domain OCT could be used for investigating SC changes in patients with glaucoma.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Use of Corneal Power-Specific Constants to Improve the Accuracy of the SRK/T Formula

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Purpose:
To evaluate the effect of average corneal power (K) and axial length (AL) in a data-adjusted A-constant for improving the refractive outcome in the Sanders–Retzlaff–Kraff (SRK)/T formula.

Design:
Retrospective, consecutive, case series.

Participants:
A total of 637 patients (637 eyes) who underwent uncomplicated phacoemulsification with implantation of the Acrysof IQ (IQ; Alcon, Fort Worth, TX; 314 eyes) or Akreos AO (AO; Bausch & Lomb, Rochester, NY; 323 eyes) intraocular lens (IOL) by a single surgeon.

Methods:
The correlation among the K, AL, and predicted refractive error in the SRK/T formula was analyzed. Patients were divided into 2 subgroups, the first to calculate the different data-adjusted A-constants based on the K and the second to compare the median absolute error (MedAE) based on different A-constants with the traditional A-constant in the SRK/T formula.

Main Outcome Measures:
The data-adjusted A-constant and the MedAE (diopters [D]).

Results:
The data-adjusted A-constant showed a decreasing trend as K increased. The data-adjusted A-constant was 119.04 in the IQ group and 118.27 in the AO group. The calculated A-constant was 119.33 in the IQ group and 118.57 in the AO group when the cornea was flatter than 43.0 D and 43.2 D, respectively. The A-constant was 118.71 in the IQ group and 117.96 in the AO group when the cornea was steeper than or equal to 44.7 D and 45.0 D, respectively. The MedAE decreased from 0.29 D to 0.23 D in the IQ group (P = 0.001) and from 0.44 D to 0.38 D in the AO group (P < 0.001) when different A-constants were used. The MedAE further decreased from 0.36 D to 0.24 D in the IQ group (P = 0.005) and from 0.58 D to 0.37 D in the AO group (P < 0.001) when subjects with K 1.00 D or more above or 1.00 D below the most accurate K in each group were compared.

Conclusions:
For a steep cornea, the calculated A-constant was smaller than that of the entire K, but for a flat cornea, a larger A-constant was calculated. Using different A-constants based on the K improved the refraction outcomes relying on the SRK/T formula.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Visualization of Blebs Using Anterior-Segment Optical Coherence Tomography after Glaucoma Drainage Implant Surgery

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Objective:
The current study investigated the internal structure of blebs using anterior-segment optical coherence tomography (AS-OCT) in patients who had undergone Ahmed glaucoma valve (AGV) (New World Medical Inc, Rancho Cucamonga, CA) implantation and compared the differences between successful and failed surgeries.

Design:
Cross-sectional, observational study.

Participants:
A total of 76 patients who had undergone AGV implantation.

Methods:
The blebs after AGV implantation were examined using AS-OCT. The relationship between intraocular pressure (IOP) or the number of glaucoma medications and intrableb parameters was evaluated. Success was defined as IOP ≤21 mmHg with a maximum of 2 glaucoma medications, and the remaining cases were assigned to the “failed surgery group.” Logistic regression was used to determine the predictive value of various bleb parameters measured by AS-OCT for bleb success.

Main Outcome Measures:
The bleb wall thickness (minimum and maximum) and the reflectivity of the bleb wall (mean, modal value, minimum, and maximum).

Results:
Blebs from 46 successful (60.5%) and 30 failed (39.5%) AGV implantation surgeries were analyzed. The AS-OCT imaging of the intrableb configuration revealed a relatively regular surface and a homogeneous and hyperreflective bleb wall. The maximum and minimum bleb wall thicknesses were significantly different between the 2 groups (P<0.001, P<0.005). No significant differences were observed between the 2 groups in mean, modal, maximum, or minimum reflectivity of the bleb wall. The maximum and minimum bleb wall thicknesses were significantly correlated with the postoperative maximum IOP (r = 0.402, P<0.001; r = 0.280, P = 0.014). The maximum and minimum bleb wall thicknesses showed a significant correlation with the number of postoperative glaucoma eye drops (r = 0.452, P<0.001; r = 0.327, P = 0.004). Maximum bleb wall thickness was significantly associated with the success of AGV surgery by multivariate analysis (P<0.001).

Conclusions:
Anterior-segment OCT can be used for bleb imaging after glaucoma valve implantation. The AS-OCT results revealed that the maximum bleb wall was significantly thinner in successful AGV implant surgeries compared with unsuccessful AGV implant surgeries. This technique may facilitate the investigation of surgical outcomes and pathogenesis in patients receiving glaucoma valve implants.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Scleral Necrosis after Plaque Radiotherapy of Uveal Melanoma: A Case-Control Study

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Purpose:
To identify risk factors and outcome of scleral necrosis after plaque radiotherapy of uveal melanoma.

Design:
Case-control study.

Participants:
A total of 73 cases with scleral necrosis and 73 controls without necrosis after plaque radiotherapy. Controls were matched for anteroposterior tumor epicenter and follow-up duration.

Intervention:
Plaque radiotherapy with iodine-125, cobalt-60, iridium-192, or ruthenium-106.

Main Outcome Measures:
Scleral necrosis.

Results:
Of 5057 patients treated with plaque radiotherapy for uveal melanoma, 73 (1%) developed radiotherapy-induced scleral necrosis. Scleral necrosis occurred in <1% of patients (3/1140) when plaque radiotherapy was used for tumors <3 mm in thickness, 1% of patients (33/3155) with 3- to 8-mm tumor thickness, and 5% of patients (37/762) with >8-mm-thick tumors. On the basis of tumor location, scleral necrosis was detected after plaque radiotherapy of iris melanoma in 0% of patients (0/91), ciliary body melanoma in 29% of patients (67/235), and choroid melanoma in <1% of patients (6/4731). The mean time interval between plaque radiotherapy and scleral necrosis was 32 months (median, 23 months; range, 4–126 months). The mean basal dimension of scleral necrosis was 4 mm (median, 3 mm; range, 1–15 mm), equivalent to 29% of mean tumor base (median, 24%; range, 6%–100%) and 22% of mean plaque size (median, 19%; range, 5%–75%). Multivariate analysis of factors that predicted clinically evident scleral necrosis included ciliary body (P = 0.0001) and pars plana to ora serrata (P < 0.0001) locations of anterior tumor margin, tumor thickness ≥6 mm (P = 0.0001), and radiation dose ≥400 Gy to the outer sclera (P = 0.0455). Scleral necrosis remained stable in 48% of patients (35/73), increased in size/severity in 48% of patients (35/73), or progressed to scleral perforation in 4% of patients (3/73) over a mean follow-up of 79 months (median, 54 months; range, 5–351 months). Treatment of scleral necrosis included observation in 81% of patients (59/73), scleral patch graft in 14% of patients (10/73), and enucleation in 5% of patients (4/73).

Conclusions:
Scleral necrosis after plaque radiotherapy of uveal melanoma was detected in 1% of cases. Factors predictive of scleral necrosis included increasing tumor thickness, ciliary body and peripheral choroidal location, and higher radiation dose to sclera. Most patients (81%) did not require treatment, and 4% evolved to full-thickness perforation.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Effect of Corneal Collagen Cross-Linking on Corneal Innervation, Corneal Sensitivity, and Tear Function of Patients with Keratoconus

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Purpose:
To evaluate the effect of corneal collagen cross-linking (CXL) on corneal innervation, corneal sensitivity, and tear function in patients with keratoconus.

Design:
Prospective, interventional case series.

Participants:
Twenty-four patients with bilateral keratoconus (30 eyes) who presented to the Institute of Vision and Optics, University of Crete, from May 2008 to October 2008.

Methods:
Patients underwent CXL. Confocal microscopic analysis of corneal sub-basal nerve plexus (total nerve length per image), corneal sensitivity (assessed with the Cochet–Bonnet esthesiometer), basic tear secretion (assessed with Schirmer’s I test with anesthesia), and tear film stability (evaluated by means of tear film break-up time [TFBUT]) were assessed preoperatively and at 1, 3, 6, 9, 12, 18, and 24 months postoperatively.

Main Outcome Measures:
Comparisons between preoperative and each postoperative value of total nerve length per image, corneal sensitivity, Schirmer’s I test results, and TFBUT.

Results:
Total nerve length per image and corneal sensitivity were significantly decreased until postoperative month 6 (for both parameters: P<0.05 paired-samples t test at 1, 3, and 6 months postoperatively). Total nerve length per image tended to increase up to 2 years postoperatively, when it reached the preoperative level, but differences with the preoperative values after the sixth post-CXL month were insignificant. The results of Schirmer’s I test and TFBUT had no statistically significant difference at any time point.

Conclusions:
A transient decrease in corneal innervation and corneal sensitivity can be observed up to 6 months after CXL. No significant effect of CXL could be detected on basic tear secretion and tear film stability in our group of patients.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Clinical Classification of Age-related Macular Degeneration

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Objective:
To develop a clinical classification system for age-related macular degeneration (AMD).

Design:
Evidence-based investigation, using a modified Delphi process.

Participants:
Twenty-six AMD experts, 1 neuro-ophthalmologist, 2 committee chairmen, and 1 methodologist.

Methods:
Each committee member completed an online assessment of statements summarizing current AMD classification criteria, indicating agreement or disagreement with each statement on a 9-step scale. The group met, reviewed the survey results, discussed the important components of a clinical classification system, and defined new data analyses needed to refine a classification system. After the meeting, additional data analyses from large studies were provided to the committee to provide risk estimates related to the presence of various AMD lesions.

Main Outcome Measures:
Delphi review of the 9-item set of statements resulting from the meeting.

Results:
Consensus was achieved in generating a basic clinical classification system based on fundus lesions assessed within 2 disc diameters of the fovea in persons older than 55 years. The committee agreed that a single term, age-related macular degeneration, should be used for the disease. Persons with no visible drusen or pigmentary abnormalities should be considered to have no signs of AMD. Persons with small drusen (<63 μm), also termed drupelets, should be considered to have normal aging changes with no clinically relevant increased risk of late AMD developing. Persons with medium drusen (≥63–<125 μm), but without pigmentary abnormalities thought to be related to AMD, should be considered to have early AMD. Persons with large drusen or with pigmentary abnormalities associated with at least medium drusen should be considered to have intermediate AMD. Persons with lesions associated with neovascular AMD or geographic atrophy should be considered to have late AMD. Five-year risks of progressing to late AMD are estimated to increase approximately 100 fold, ranging from a 0.5% 5-year risk for normal aging changes to a 50% risk for the highest intermediate AMD risk group.

Conclusions:
The proposed basic clinical classification scale seems to be of value in predicting the risk of late AMD. Incorporating consistent nomenclature into the practice patterns of all eye care providers may improve communication and patient care.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Photoreceptor Outer Segment Length: A Prognostic Factor for Idiopathic Epiretinal Membrane Surgery

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Purpose:
To investigate prognostic factors for visual improvement in patients undergoing vitrectomy for epiretinal membrane (ERM) using spectral domain (SD) optical coherence tomography (OCT).

Design:
Prospective cohort study.

Participants:
A total of 41 eyes of 38 patients.

Methods:
A total of 41 eyes of 38 patients with idiopathic ERM underwent ERM resection. Ophthalmic evaluations included best-corrected visual acuity (BCVA) and OCT parameters before and 1, 3, and 6 months after surgery. Correlations between OCT parameters and BCVA were assessed at each time point. Correlations between postoperative BCVA and preoperative factors were evaluated, including age, preoperative BCVA, photoreceptor outer segment (PROS) length, central foveal thickness (CFT), outer foveal thickness (OFT), and outer nuclear layer thickness (ONLT). The factors influencing postoperative BCVA were evaluated using multiple regression analysis.

Main Outcome Measures:
The BCVA at 6 months postoperatively.

Results:
The PROS length had the most significant correlation with BCVA at each time point (baseline: P = 0.0098, r = −0.409; 1 month: P = 0.0002, r = −0.586; 3 months: P < 0.0001, r = −0.642; 6 months: P = 0.0002, r = −0.577). The PROS length 1 month postoperatively was significantly decreased compared with that preoperatively (P = 0.0325), and the PROS length at 3 months recovered to the baseline length. Preoperative BCVA and PROS length were significantly correlated with postoperative BCVA at 6 months (P = 0.0055, r = 0.439 and P = 0.0089, r = −0.414, respectively). Other parameters, including age, CFT, OFT, and ONLT, were not significantly correlated with postoperative BCVA. Multiple regression analysis showed that preoperative PROS length yielded the highest regression coefficient with postoperative BCVA (P = 0.0363, standard regression coefficient = −0.335, overall R2 = 0.289).

Conclusions:
Imaging of PROS length with SD-OCT was found to be a good indicator of BCVA at each time point after surgery and a predictor of postoperative BCVA in patients with idiopathic ERM. The PROS length changes after surgery may indicate surgical injury and restoration of the macular outer layer.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Rheumatoid Arthritis–Associated Corneal Ulceration: Mortality and Graft Survival

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Purpose:
To investigate mortality and graft survival in patients undergoing penetrating keratoplasty (PKP) for rheumatoid arthritis–associated corneal ulceration (RACU), Fuchs’ endothelial dystrophy (FED), and pseudophakic bullous keratopathy (PBK).

Design:
Case-control study.

Participants and Controls:
Patients listed on the UK Transplant Registry who had undergone a PKP for RACU, FED, or PBK between January 4, 1999, and January 4, 2006. Comparative standardized mortality ratios (SMRs) and causes of death were obtained from the Office for National Statistics.

Methods:
Outcome data were collected from the UK Ocular Tissue National Transplant database and supplementary questionnaires at transplantation and at 1, 2, and 5 years. Institutional review board approval for the National Health Service Blood and Transplant to undertake the study was obtained.

Main Outcome Measures:
Mortality and graft survival.

Results:
A total of 3665 patients were included: RACU (117), PBK (1701), and FED (1847). Five-year survival of patients with RACU was 42% (95% confidence interval [CI], 26–56) compared with 76% (95% CI, 72–78) for FED and 55% for PBK (95% CI, 50–60; P < 0.01). The SMRs for female and male patients with RACU were 43.5 (95% CI, 19.5–63.3) and 12.2 (95% CI, 7.1–19.5), respectively, in comparison with 1.84 and 1.45 for patients with RA, respectively (P < 0.01). There were no significant differences in the causes of death among patients with RACU, FED, or PBK (P > 0.9), with infection the most common cause. The 5-year graft survival rate was 48% (95% CI, 32–62) for RACU, 59% (95% CI, 56–62) for PBK, and 84% (95% CI, 82–86) for FED (P < 0.01).

Conclusions:
Mortality and ocular morbidity were significantly increased in patients with RACU. Accelerated immunosenescence should be considered in the differential diagnosis of patients presenting with RACU, and a multidisciplinary approach to management is required.

Financial Disclosure(s):
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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