Peripapillary retinal nerve fiber layer thickness as a diagnostic tool for pseudophakic cystoid macular edema.

PURPOSE: To investigate the effects of pseudophakic cystoid macular edema (PCME) on retinal nerve fiber layer (RNFL) thickness before and after treatment using optical coherence tomography (OCT). METHODS: A retrospective, observational study of consecutive patients diagnosed with PCME after cataract surgery. Patients underwent macular and RNFL OCT imaging at time of diagnosis and during follow up. OCT was performed for both the study eye and the contralateral healthy eye which served as control. All patients were followed for a period of at least 6 months. RESULTS: Overall, 40 eyes of 40 patients with a mean age of 71.1 ± 8.1 years of which 45% (n = 18) were of male gender were included in this study. At presentation, the central thickness in the PCME eye was significantly higher than in the contralateral eye (515.7 ± 127.9µm versus 238.1 ± 41.8µm, p < 0.001). Similarly, all macular measurements were significantly higher in the PCME eye compared to the contralateral eye (p < 0.001 for all). In terms of RNFL measurements, the PCME eyes had greater global (p < 0.001), superonasal (p = 0.001) and superotemporal (p = 0.005) thickness values. PCME eyes demonstrated a significant decrease in thickness for all macular and RNFL parameters following resolution of CME (p < 0.05 for all). CONCLUSIONS: PCME patients presents with greater global, superotemporal and superonasal RNFL thickness in comparison to the other healthy eye. After resolution of PCME, there is significant thinning of RNFL. Peripapillary RNFL thickness may serve as an additional parameter for diagnosis and follow-up of PCME.

Sensory Changes in the Ocular Surface After Pterygium Removal.

Purpose: We measure changes in ocular surface sensation after pterygium surgery with a conjunctival autograft. Methods: This prospective, interventional study was carried out in patients, with nasal primary pterygium undergoing pterygium surgery with conjunctival autograft. Sensation was measured by applying the tip of the Cochet-Bonnet esthesiometer filament perpendicular to the ocular surface in the cornea and conjunctiva. Patients were tested preoperatively (baseline), and at 2 weeks, 2 and 4 months, postoperatively. Results: Nineteen eyes of 18 patients completed the 4-month follow-up. Mean age was 61±10.1 (range 36-76) years. Corneal sensation returned to normal values in all at 2 and at 4 months. The central cornea was significantly more sensitive compared to the average of the four peripheral measurements pre- (59.2 mm vs 48.3 mm, p=0.000) and postoperatively (59.2 mm vs 48.4 mm, p=0.000). Conjunctival sensation was reduced significantly 2 months postoperatively in the inferior region (p=0.04). Four months postoperatively, it was more sensitive in the superior area (13.9 mm vs 17.1 mm, p=0.01) and the inferior area (13.7 mm vs 19.5 mm, p=0.003). In each matching area, the cornea was significantly more sensitive than the conjunctiva pre- and postoperatively (p=0.00). Sensation was not significantly different between the sexes or age groups. Conclusion: This study demonstrates the presence of inferior and superior conjunctival hyperesthesia at conjunctival autograft sites after pterygium surgery. The healing process, sensory input, tear film instability and epitheliopathy of the ocular surface are possible explanations for these novel findings.

Long-term outcomes of anti-vascular endothelial growth factor treatment in peripapillary choroidal neovascularisation due to age-related macular degeneration.

OBJECTIVE: To report the long-term outcomes of anti-vascular endothelial growth factor (VEGF) treatment in eyes with peripapillary choroidal neovascularisation (PPCNV) associated with age-related macular degeneration (AMD). METHODS: A retrospective cohort study included patients with AMD-related PPCNV. Eyes were treated with anti-VEGF according to pro re nata regimen. Inactivation index was calculated as the proportion of disease inactivity from the total follow up time. RESULTS: Sixty-seven eyes of 66 consecutive patients were included in the study; mean follow-up time was 53.2 months. Best corrected visual acuity (BCVA) remained stable for the first four years of follow up, with a significant deterioration in BCVA thereafter. Baseline BCVA was a significant predictor of final BCVA (p < 0.001). The mean inactivation index was 0.38 ± 0.23. Subretinal fluid (SRF) at presentation was significantly associated with decreased inactivation index (p < 0.05). Worse baseline BCVA, SRF and pigment epithelium detachment (PED), male sex, and younger patient age were associated with increased risk for recurrence after first inactivation (p < 0.05). CONCLUSION: The use of anti-VEGF agents in the treatment of AMD-related PPCNV managed to preserve BCVA in the first four years of follow-up. Male sex, SRF and PED at presentation and baseline BCVA are associated with increased risk for PPCNV recurrence after the first inactivation, and should prompt careful follow-up in these patients.

The Orbital Bones Protect the Globe From Sharp Periorbital Trauma Injuries.

BACKGROUND: The bones of the orbit hold the globe and periocular structures and protect it and other periocular contents. This has been shown in blowout orbital fractures, as well as in high-energy injuries to the periorbital region. However, there is little information regarding how the orbital bones protect the globe after periorbital trauma from sharp objects. OBJECTIVES: This study reports 4 cases of traumatic injury from sharp objects to the periorbital area and eyelids to demonstrate the protective features of the orbital bones. RESULTS: The anatomy of the periorbital bones clearly protected the globe from direct trauma in all the 4 cases. CONCLUSIONS: There was no harm to the orbit or visual impairment after the successful treatment with definitive surgery.

Optical Coherence Tomography Biomarkers Predicting Visual Acuity Change after Intravitreal Bevacizumab Injections for Macular Edema Secondary to Branch Retinal Vein Occlusion.

PURPOSE: This study aimed to identify baseline optical coherence tomography (OCT) factors in branch retinal vein occlusion (BRVO) that predict response to bevacizumab injections. METHODS: It is a retrospective case series of consecutive patients that underwent OCT at diagnosis, and the central macular thickness (CMT), extent of disorganized retinal inner layers, and outer retinal layers including external limiting membrane, ellipsoid zone (EZ), and cone outer segment tips (COST) were measured. Patients received 3 consecutive monthly injections of bevacizumab followed by pro re nata treatment. The main outcome measure was improvement in best-corrected visual acuity (BCVA) after 1 year. Results are expressed as mean ± SD, and p value <0.05 was considered statistically significant. RESULTS: Overall, 66 eyes of 66 patients, with an average age of 68.5 ± 11.4 years, were included. The mean BCVA improved significantly from 0.68 logMAR at baseline to 0.50 logMAR at 1 year (p < 0.001). Baseline logMAR BCVA (r = 0.41, p < 0.001) and CMT (r = 0.23, p = 0.04) were associated with improvement while EZ (r = -0.24, p = 0.05) and COST (r = -0.32, p = 0.01) disruption with deterioration in BCVA. CONCLUSION: In patients with naïve BRVO treated with bevacizumab, BCVA improvement at 1 year can be predicted from baseline BCVA, CMT, extent of COST disruption, and EZ disruption.

Optical Coherence Tomography Prognostic Factors in Age-Related Macular Degeneration Patients with Peripapillary Choroidal Neovascularization.

PURPOSE: The aim of the study was to investigate the correlation between optical coherence tomography (OCT) findings and visual acuity outcomes after treatment with intravitreal bevacizumab (IVB) injections for age-related macular degeneration (AMD) patients with peripapillary choroidal neovascularization (PPCNV). METHODS: The study involved a retrospective case series of consecutive patients diagnosed with PPCNV secondary to AMD. All patients were treated with IVB injections with a follow-up time of 1 year. Data collected included best-corrected visual acuity (BCVA) and automated and manually measured OCT parameters. RESULTS: A total of 68 eyes were diagnosed with PPMV. Of them, 30 eyes of 30 patients aged 84.3 ± 6.9 years of which 63.3% female gender were included. Baseline BCVA was 0.46 ± 0.62 logMAR (Snellen 20/57), average choroidal thickness was 193.2 ± 22 µm, and mean number of IVB injections was 7.2 ± 1.9. After 1 year, BCVA was 0.56 ± 0.78 logMAR (Snellen 20/72) (p = 0.28). Eyes with greater central retinal thickness (r = -0.36, p = 0.05), greater subretinal hyper-reflective material (SHRM) area (r = -0.37, p = 0.05), and greater sub-retinal fluid (SRF) area (r = -0.73, p < 0.001) had a significantly smaller improvement in BCVA. Eyes with pigment epithelium detachment (PED) (0.68 ± 0.90 vs. 0.21 ± 0.12, p = 0.03) had a significantly worse BCVA. CONCLUSIONS: Our data suggest that AMD-related PPCNV with greater foveal thickness, PED size, SHRM, and SRF areas have worse final BCVA prognosis.

Predicting response of ischemic central retinal vein occlusion to bevacizumab injections: 1 year follow-up.

PURPOSE: To identify baseline optical coherence tomography (OCT) factors in ischemic central retinal vein occlusion (CRVO) that predict response to bevacizumab injections. METHODS: Patients underwent OCT at diagnosis and the central macular thickness, subretinal fluid width and height as well as the presence of intraretinal cysts were measured. The extent of disorganized retinal inner layers, outer plexiform layer (OPL), external limiting membrane, ellipsoid zone and cone outer segment tips (COST) was recorded. Patients received three consecutive monthly injections of bevacizumab followed by pro re nata treatment. RESULTS: Overall 32 eyes of 32 patients aging 69.4 ± 12.7 years were included. In univariate correlational analyses baseline OPL disruption (- 41, p = 0.02), EZ disruption (r = - 0.36, p = 0.05) and COST disruption (r = - 0.37, p = 0.04) correlated with deterioration in BCVA at 1 year. Partial least squares demonstrated that the factors most largely associated with deterioration in BCVA were COST disruption and OPL disruption followed by EZ disruption, while worst vision at baseline was associated with improvement in vision. CONCLUSION: In patients with ischemic CRVO treated with bevacizumab, BCVA improvement at 1 year can be partially predicted from baseline OCT measurements by the extent of COST, OPL and EZ disruption.

Age- and Gender-Related Characteristics of Corneal Refractive Parameters in a Large Cohort Study.

PURPOSE: To characterize age- and sex-related changes in corneal refractive parameters in myopic and hyperopic patients undergoing refractive surgery. DESIGN: A retrospective cross-sectional study. METHODS: Analysis of demographic and refractive parameters of myopic and hyperopic patients who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between January 2000 and December 2014 at the Care-Vision Laser Centers, Tel-Aviv, Israel. RESULTS: A total of 62,422 eyes of 31,211 patients were included. With advancing age, refractive surgery was performed for lower magnitudes of myopia and hyperopia. The magnitude of cylinder was higher in men than in women in both myopic and hyperopic patients. In comparison, women were significantly more myopic than men (spherical equivalent of -3.73 diopter [D] versus -4.07 D; P < 0.01). The myopic group sphere (r = 0.044; P < 0.001) had a positive correlation with age, whereas other parameters had a negative correlation with age: astigmatism (r = -0.09; P < 0.001), best-correct visual acuity (BCVA) (r = -0.04; P < 0.001), flat K (r = -0.09; P < 0.001), steep K (r = -0.06; P < 0.001), average K (r = -0.07; P < 0.001), and J0 (r = -0.05; P < 0.001). For hyperopic patients, astigmatism (r = 0.35; P < 0.001), BCVA (r = 0.11; P < 0.001), flat K (r = 0.30; P < 0.001), average K (0.14; P < 0.001), and central corneal thickness (r = 0.10; P < 0.001) correlated positively with age, whereas sphere (r = -0.23; P < 0.001), J0 (r = -0.31; P < 0.001), and overall blurring strength (r = -0.31; P < 0.001) had negative correlations with age. CONCLUSIONS: This large cohort study shows age- and sex-related refractive parameters among myopic and hyperopic patients seeking refractive surgery. These parameters can explain and predict trends in patients attending refractive surgery.

Primary Lash Ptosis.

INTRODUCTION: Lash ptosis is often an overlooked sign that may coexist with congenital and acquired blepharoptosis. This is a report of case series of patients presented in an oculoplastic clinic with visual field loss associated with lash ptosis. On examination, the primary pathology was attributed to lash ptosis dehiscence. METHODS: All patients underwent anterior lamellar repositioning and were followed for an average of 15 (10-24) months. RESULTS: All patients had resolution of visual field loss and heaviness of eyelids. CONCLUSIONS: Lash ptosis is associated with abnormalities such as floppy eyelid syndrome. However it may be a primary condition, with no background eyelid pathology and no external explanation for the eyelash ptosis. The condition might result from anatomical changes in the orbicularis oculi, Riolan's muscle, and tarsal plate. Patients in this series complained of upper lid visual field restriction. Anterior lamellar repositioning resulted in complete resolution of complaints. Additional studies are needed to learn about the pathophysiology of this entity.

Brow Ptosis: Is Transblepharoplasty Internal Browpexy Suitable for Everyone?

PURPOSE: Transcutaneous internal browpexy can provide patients with mild-to-moderate lateral brow ptosis, stabilization and modest lift of the lateral brow. Questions regarding effectiveness of this procedure and appropriate indications remain. METHODS: The authors measured consecutive patients who underwent upper eyelid blepharoplasty with transblepharoplasty internal browpexy (TIB) September 2014 to December 2017. Pre- and postoperative brow elevation was assessed based on before and after photographs of each patient. Patient photographs were assessed for medial and lateral brow elevation, brow contouring and asymmetry. Optimal lateral brow elevation was classified as bilateral symmetrical and above the supraorbital rim for women, and symmetrical and at the supraorbital rim for men. RESULTS: A total of 239 patients underwent bilateral TIB and 39 underwent unilateral TIB (517 eyelids in total). Pre- and post-operative measurements were taken in 98 patients (41%), with an average elevation of the lateral brow position of 2.54 mm.Six patients had an underlying infection in the first postoperative week that resolved completely. Three patients underwent a second stage direct brow lift repair and 3 needed unrecognized ptosis repair as a second stage. CONCLUSIONS: Transblepharoplasty internal browpexy is an important tool that can be used in most patients with lateral and central brow ptosis, asymmetric brow ptosis and irregular contour of the brow. Additionally, browpexy adds to the success and longevity of upper blepharoplasty, while preventing early recurrence of lateral upper eyelid hooding. Patients with significant ptosis, heavy brows, medial greater than lateral ptosis, and post-facial palsy may not be good candidates for this procedure.

Objective Measurement of Eyelid Force in Ptosis Versus Controls.

Thorough evaluation of the upper eyelid is essential for diagnosis and management planning in blepharoptosis. In a previous study, our group described a novel force gauge for direct assessment of upper lid force in healthy subjects. In this study, the authors apply the same technique for measuring muscle forces in ptotic eyelids.Patients scheduled to undergo surgical repair of aponeurotic blepharoptosis or dermatochalasis, from July 2017 to August 2018, in a tertiary care medical center, were enrolled in this prospective case series. When the eyelid disorder was unilateral, the normal eye was designated as control. The upward force generated by the eyelid was measured directly using a handheld dynamometer noninvasively attached to the upper eyelid. Measurements were conducted with and without fixation of the frontalis muscle, to differentiate between total lid force, levator force, and frontalis contribution.A total of 56 eyes was included in the study: 34 in the ptosis group, 11 in the dermatochalasis group, and 11 as controls. Both the ptosis group and the dermatochalasis group had significantly lower total muscle force and levator force measurements when compared with control (P <0.05). Calculated frontalis force contribution to upgaze did not differ significantly between groups. In the control group, calculated frontalis force contribution to upgaze strongly correlated to marginal reflex distance1 (r = 0.75, P = 0.05)In conclusion, the authors present a simple, inexpensive, new portable force gauge for direct eyelid force measurements in eyelid pathologies. Distinct differences between ptotic and healthy eyelids are demonstrated, suggesting potential applications in patient evaluation and management.

Sensory Changes in Periocular Skin After Upper Eyelid Surgery.

The aim of this interventional, prospective study is to estimate the change in periocular cutaneous sensation after upper eyelid surgery. The trial included 48 eyes of 24 patients undergoing upper eyelid blepharoplasty or upper eyelid blepharoplasty and blepharoptosis repair. Eyelid sensation was measured using a Cochet-Bonnet filament-type esthesiometer at 4 predetermined anatomical locations in the upper eyelid. The mean esthesiometry reading was calculated at the preoperative visit (4.06 cm), at 2-week postoperative visit (4.38 cm), and at final postoperative visit (4.52 cm). Paired t test showed no significant difference in sensation measurement at second visit compared with baseline (P = 0.205) or at final visit compared with baseline (P = 0.092). Paired t test showed no correlation between type of surgery and change in sensation. Sex and age did not influence change in sensation. In 40 of 42 eyelids, (95.24%), patients reported no reduction in subjective eyelid sensation. The authors conclude that eyelid sensation was not compromised objectively or subjectively by upper eyelid skin incision surgery. Surgeons can reassure patients contemplating surgery that it is very unlikely that cutaneous sensation will be damaged.

Isolated Superior Rectus Muscle Hematoma Following Blunt Orbital Trauma.

Isolated ocular muscle hematoma due to blunt trauma is very rare. In this study, a 15-year-old patient presented with an isolated superior rectus hematoma due to an orbital hit from a cellular phone. He was treated with oral corticosteroids alone. Marked improvement in symptoms and eye movements was observed.

Bevacizumab dosing every 2 weeks for neovascular age-related macular degeneration refractory to monthly dosing.

PURPOSE: To evaluate intravitreal bevacizumab every 2 weeks (biweekly) in refractory neovascular age-related macular degeneration (nAMD). STUDY DESIGN: Retrospective study. METHODS: A retrospective study of consecutive nAMD patients unresponsive to monthly intravitreal anti-vascular endothelial growth factor (VEGF) switched to 3-4 biweekly injections. RESULTS: Twenty-seven eyes of patients aged 82.08 ± 6.85 years were included. Prior to the 2-week interval bevacizumab injections, 74.1% (n=20) were treated with both bevacizumab and ranibizumab, 11.1% (3 eyes) also received aflibercept and 14.8% (4 eyes) had received prior treatment of monthly bevacizumab (average number of injections 21.5 ± 6.7). Best corrected visual acuity (BCVA) remained stable between baseline (logMAR 0.72± 0.60) and follow-up (0.76± 0.66) (p=0.41). Mean central macular thickness and macular volume did not change significantly between baseline and follow-up (p=0.35 and p=0.60, respectively). Six eyes (22.2%) showed morphologic anatomic improvements, while 19 eyes (70.4%) were stable and two eyes (7.4%) deteriorated from baseline. Subretinal fluid completely resolved in 3 of the eyes and improved in the other 3 eyes and in this group (22.2%) both central macular thickness (326.2 ± 101.4 versus 297.5 ± 97.2, p=0.002) and macular volume (8.69 ± 1.69 versus 8.22 ± 1.43, p=0.03) were significantly reduced. No adverse events were observed in any of the treated eyes. CONCLUSION: This study demonstrates that biweekly bevacizumab injections are effective in nearly one-quarter of nAMD non-responders with no adverse events reported. Switching earlier, rather than later, to this low cost modality may be of benefit for a portion of non-responders to conventional treatment.

Risk Factors for Epithelial Ingrowth Following Microkeratome-Assisted LASIK.

PURPOSE: To analyze the incidence and risk factors associated with epithelial ingrowth following uncomplicated microkeratome-assisted LASIK. METHODS: All patients who underwent microkeratome-assisted LASIK between January 2006 and December 2014 in a single surgical center were reviewed. Epithelial ingrowth cases were identified and associated factors were assessed. RESULTS: Overall, 149 (0.49%) of 30,574 cases developed epithelial ingrowth. The epithelial ingrowth group was older compared to controls (35.3 ± 12.3 vs 31.7 ± 10.3 years, P = .001) and had a higher percentage of moderate to high hyperopia (13.7% vs 5.3%, P < .001), early postoperative flap slippage requiring flap repositioning (9.4% versus 2.8%, P < .001), or flap lifting for enhancement (48.6% vs 4.3%, P < .001), were treated with a smaller optic zone (6 mm) (37.7% vs 15.2%, P < .001), with a Moria M2 microkeratome (Moria SA, Antony, France) (70.1% vs 55.5%, P = .02), by low volume surgeons (n < 1,000) (5.8% vs 1.3%, P < .001), in a lower operating room temperature (22.3 ± 1.8 vs 22.8 ± 1.6, P = .005), and with a greater maximum ablation depth (67.3 ± 29.7 vs 57.3 ± 30.3, P < .001). There was a high incidence of epithelial ingrowth in the enhancement group compared to primary LASIK (4.8% vs 0.2%, P < .001). The time between treatments (primary and enhanced LASIK) was significantly greater in the epithelial ingrowth group (mean: 1,110 ± 870 vs 626 ± 662 days, P < .001). There was a significant rise in epithelial ingrowth rates as time between primary and enhancement LASIK increased, peaking at 4 to 5 years (P < .001). In multivariate analysis, flap lifting for enhancement (odds ratio [OR] = 19.5, P < .001), 6-mm optic zone (OR = 2.2, P < .001), moderate to severe hyperopia (OR = 2.4, P = .005), greater ablation depth (OR = 1.005, P < .001), and low volume surgeon (OR = 3.9, P = .01) were associated with epithelial ingrowth (total R2 = 15.4). CONCLUSIONS: The potential risk factors described above may forewarn surgeons as to which individuals merit closer observation for this complication. [J Refract Surg. 2018;34(2):100-105.].

A Novel Technique for Measuring Eyelid Force.

PURPOSE: We present a novel technique to directly measure the eyelid upward force generation. This technique can be used during routine clinical examination using an inexpensive, portable force gauge. METHODS: This prospective case series was conducted January to June 2015 in an ophthalmology clinic affiliated with a tertiary care medical center. A convenience sample of 42 patients (40-90 years of age) without known eyelid pathology participated. The eyelid upward net force generated was measured directly using a handheld dynamometer noninvasively attached to the upper eyelid. Comparison of the eyelid-brow upward force generated with eyelid upward net force generated allowed us to assess the contribution of levator and frontalis muscles to the force generated during upgaze. Data were evaluated with relation to gender and age. RESULTS: Upper eyelid force generated was 53.3 g OD and 53.9 g OS; the generated force during frontalis muscle fixation was 38.4 g OD and 41.1 g OS. The levator and frontalis muscles showed a 3:1 ratio respectively in their contribution to the force generated during upgaze. Although no statistically significant differences were seen between eyes, gender, or within age groups, younger patients showed increased generating force which is attributed to the levator muscle. Interclass correlation coefficient showed virtually no correlation between clinical eyelid assessments and direct muscle force measurement. Reliability for repeated direct force measurements by the same physician was strong, with interclass correlation coefficient 0.951 to 0.969. No adverse events occurred. CONCLUSIONS: We describe a simple, reliable, inexpensive, new method for assessing upper eyelid upward force generation. Because the levator muscle serves as the primary contributor to eyelid elevation, this directly measurable eyelid assessment may help to increase understanding of its functional contribution and assessment when assessing eyelid pathologies.

PROGNOSTIC VALUE OF SUBRETINAL HYPERREFLECTIVE MATERIAL IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION TREATED WITH BEVACIZUMAB.

PURPOSE: To study the correlation between subretinal hyperreflective material (SHRM) seen on spectral domain optical coherence tomography at baseline and visual outcomes after intravitreal bevacizumab injection in neovascular age-related macular degeneration. METHODS: Consecutive patient charts with treatment-naive center-involved neovascular age-related macular degeneration treated with 3 monthly intravitreal bevacizumab's, continued as needed, from 2011 to 2014 were reviewed. Baseline spectral domain optical coherence tomography SHRM parameters (height, width, area, reflectivity, border definition, and homogeneity) and established optical coherence tomography biomarkers of neovascular activity (intraretinal fluid, subretinal fluid, retinal volume, central retinal thickness, and pigment epithelial detachment presence) were collected. These baseline parameters were correlated with visual acuity at baseline, 3 and 12 months. RESULTS: Seventy-three eyes of 73 patients, 47 (64.4%) having central SHRM at baseline, were studied. Mean age was 79.2 ± 8.9 years. Mean best-corrected visual acuity was 0.70 ± 0.57 logarithm of the minimum angle of resolution (20/100), 0.73 ± 0.55 (20/107), and 0.76 ± 0.63 (20/115) at baseline, 3 and 12 months, respectively. Baseline parameters with a significant predictive value of 12-month visual acuity by univariate analysis were presence of intraretinal fluid, presence of SHRM, highly reflective SHRM, well-defined SHRM borders, and thick SHRM. These parameters, with the exception of high reflectivity, were significant on multivariate regression analysis. The most predictive baseline parameter was well-defined SHRM borders. CONCLUSION: This study supports the use of SHRM as a prognostic biomarker when interpreting optical coherence tomography in neovascular age-related macular degeneration. Baseline parameters predicting poorer vision 1 year after intravitreal bevacizumab treatment were as follows: presence of central SHRM, well-defined SHRM borders, intraretinal fluid, and thicker SHRM.

Relationship between macular thickness measurement and signal strength using Stratus optical coherence tomography.

PURPOSE: To examine the relationship between signal strength and macular thickness as measured by Stratus optical coherence tomography (OCT)'s fast macular thickness protocol in healthy subjects. METHODS: In this prospective cross-sectional study 79 eyes of 42 healthy subjects were enrolled. The age, gender, and eye (right vs left) of each subject were recorded. The Stratus OCT fast macular thickness scan protocol was used and the macular thickness was measured with retinal thickness map analysis. Each eye was imaged at least six times to acquire images with signal strengths of 4, 5, 6, 7, 8, and 9 out of 10 via adjustment of the focusing knob. The OCT parameters included in the analysis were thickness in the central 1 mm and in the different quadrants in the 3-mm area. RESULTS: Overall 79 eyes of 42 patients with a mean age of 38.4±12.4 were included. There was no significant difference between the signal strength measurements obtained with different signal strengths in the central thickness (P=0.20). In the superior, nasal, inferior, and temporal quadrants, a signal strength of 8 demonstrated up to 3 µm thicker measurements than a signal strength of 5 (P<0.05). In general linear regression analysis, after accounting for age and gender, signal strength did not remain a significant predictor of thickness in any quadrant. CONCLUSIONS: When using fast map macular measurements, a signal strength of 5 is clinically as efficient as a signal strength of 8 in measuring macular thickness in all quadrants. Insisting on higher signal strength may not be necessary.