Jonathan E. Moore

The Development of an Instrument to Measure Quality of Vision: The Quality of Vision (QoV) Questionnaire

PURPOSE To develop an instrument to measure subjective quality of vision: the Quality of Vision (QoV) questionnaire. METHODS A 30-item instrument was designed with 10 symptoms rated in each of three scales (frequency, severity, and bothersome). The QoV was completed by 900 subjects in groups of spectacle wearers, contact lens wearers, and those having had laser refractive surgery, intraocular refractive surgery, or eye disease and investigated with Rasch analysis and traditional statistics. Validity and reliability were assessed by Rasch fit statistics, principal components analysis (PCA), person separation, differential item functioning (DIF), item targeting, construct validity (correlation with visual acuity, contrast sensitivity, total root mean square [RMS] higher order aberrations [HOA]), and test-retest reliability (two-way random intraclass correlation coefficients [ICC] and 95% repeatability coefficients [R(c)]). RESULTS Rasch analysis demonstrated good precision, reliability, and internal consistency for all three scales (mean square infit and outfit within 0.81-1.27; PCA >60% variance explained by the principal component; person separation 2.08, 2.10, and 2.01 respectively; and minimal DIF). Construct validity was indicated by strong correlations with visual acuity, contrast sensitivity and RMS HOA. Test-retest reliability was evidenced by a minimum ICC of 0.867 and a minimum 95% R(c) of 1.55 units. CONCLUSIONS The QoV Questionnaire consists of a Rasch-tested, linear-scaled, 30-item instrument on three scales providing a QoV score in terms of symptom frequency, severity, and bothersome. It is suitable for measuring QoV in patients with all types of refractive correction, eye surgery, and eye disease that cause QoV problems.

Multifocal intraocular lens with a surface-embedded near section: Short-term clinical outcomes

PURPOSE: To evaluate the visual and refractive outcomes and quality of life after implantation of a multifocal intraocular lens (IOL) with a surface‐embedded near section. SETTING: Private practice, United Kingdom. DESIGN: Case series. METHODS: This study comprised patients who had implantation of a Lentis Mplus multifocal IOL after phacoemulsification. The main outcome measures were refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities (logMAR), uncorrected (UNVA) and corrected (CNVA) near visual acuities (M notation), reading speed (Radner reading chart), contrast sensitivity (Pelli‐Robson), and Quality of Life Impact of Refractive Correction (QIRC) questionnaire scores. A +3.00 diopter (D) reading addition (add) IOL was placed in the nondominant eye and a +1.50 D add IOL in the dominant eye. RESULTS: The study enrolled 44 eyes of 22 patients (mean age 59.9 years). The mean values 3 months postoperatively were UDVA, 0.04 logMAR ± 0.25 (SD); contrast sensitivity, 1.57 ± 0.13 logCS; near vision, M0.75 ± 0.33 at 32 cm and M0.90 ± 0.27 at 66 cm; reading speed, 161.74 words/minute; sphere, 0.08 ± 0.58 D; astigmatism, −0.60 ± 0.50 D; CDVA, −0.08 ± 0.07 logMAR. With best correction, intermediate (66 cm) and near (32 cm) vision were M0.89 ± 0.26 and M0.74 ± 0.32, respectively. The mean binocular UNVA at the preferred viewing distance was M0.57 ± 0.18, improving to M0.54 ± 0.19 with distance correction. The mean QIRC score improved from 42.15 ± 4.66 to 51.14 ± 8.22. CONCLUSIONS: Postoperative visual acuity was good with high‐level contrast sensitivity, producing significant improvement in quality of life. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Quality of vision after myopic and hyperopic laser-assisted subepithelial keratectomy

PURPOSE: To assess quality of vision after laser‐assisted subepithelial keratectomy (LASEK). SETTING: Private practice, United Kingdom. DESIGN: Case series. METHODS: Consecutive patients having bilateral LASEK with a Schwind Amaris laser for myopia, hyperopia, or astigmatism completed the Quality of Vision (QoV) questionnaire preoperatively and 5 days, 2 weeks, and 1 and 3 months postoperatively. The outcome measures were QoV scores for symptom frequency, severity, and bothersome. The QoV scores range from 0 to 100; higher scores indicate poorer quality of vision. RESULTS: The study enrolled 100 consecutive patients (68 myopic, 32 hyperopic). For frequency of symptoms, the mean preoperative QoV score was 6.78 ±11.45 (SD). Postoperatively, the mean scores at 5 days, 2 weeks, 1 month, and 3 months were 70.71 ± 11.26, 50.55 ± 14.63, 7.15 ± 12.49, and 2.45 ± 6.01, respectively. For severity of symptoms, the mean preoperative QoV score was 6.22 ± 10.52 and the mean postoperative scores were 54.85 ± 12.19, 38.95 ± 11.42, 4.38 ± 7.80, and 1.94 ± 4.64, respectively. For bothersome nature of symptoms, the mean preoperative QoV score was 4.91 ± 9.48 and the mean postoperative scores were 38.97 ± 24.18, 21.90 ± 16.50, 3.61 ± 7.01, and 1.44 ± 4.91, respectively. Post hoc tests found statistically significant differences for all comparisons except between preoperatively and 1 month postoperatively. There were no statistically significant differences between the 2 groups at any time interval. CONCLUSION: The quality of vision worsened in the early postoperative period but returned to preoperative levels by 1 month and was better than preoperative levels by 3 months post LASEK. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Comparison of higher order aberrations after LASIK and LASEK for myopia.

PURPOSE To compare the change in higher order aberrations (HOAs) after LASIK and laser epithelial keratomileusis (LASEK). METHODS This prospective comparative study measured HOAs preoperatively and 3 months postoperatively in 65 eyes (41 patients) that underwent LASIK and 65 eyes (50 patients) that underwent LASEK. Preoperative refraction was limited to myopia up to -5.00 diopters (D) and astigmatism <or=-0.75 D. Patients were matched for age, manifest refraction, and HOAs. All procedures were wavefront-guided using the VISX S4 Star excimer laser (Abbott Medical Optics). Laser in situ keratomileusis flap creation was performed with a Moria ONE Use-Plus disposable microkeratome creating a nasal hinge. Laser epithelial keratomileusis flap creation was performed with 18% v/v unpreserved ethanol instilled for 40 seconds. The epithelium was displaced with an epi-peeler, creating a 6- to 8-mm superior hinge. Higher order aberrations were measured with the NIDEK OPD-Scan II. RESULTS Statistically significant (P<.05) changes in five Zernike polynomial terms following LASIK ( Z4-4, Z40, Z44, Z5-3, Z60) were noted. There was a decrease in Zernike term Z5-3 and increases in the remaining four Zernike terms. Statistically significant changes in five Zernike polynomial terms following LASEK ( Z3-1, Z40, Z5-5, Z5-1, Z60) were noted. There was a decrease in Zernike term Z3-1 and increases in the remaining four Zernike terms. CONCLUSIONS Wavefront-guided LASIK and LASEK caused increases in spherical aberration, with LASIK additionally causing increases in two fourth order HOAs and LASEK additionally causing increases to two fifth order HOAs. As the same laser treatment was applied, it is presumed that the differences relate to the method of flap creation.

Subscale Assessment of the NEI-RQL-42 Questionnaire with Rasch Analysis

PURPOSE To explore the psychometric properties of the 13 subscales of the NEI-RQL-42 questionnaire using Rasch analysis. METHODS The NEI-RQL-42 is a refractive error-related quality of life (QoL) questionnaire with a complex design; its 13 subscales contain 42 questions, which include 16 different question/response category formats. It was completed by 100 laser refractive surgery subjects (spectacle and contact lens wearers) pre- and postoperatively. Rasch analysis was used to assess the use of response categories, success in measuring a single trait per subscale (unidimensionality), ability to discriminate persons (precision), and targeting of the questions to person QoL. RESULTS Response categories were misused in four subscales (clarity of vision, diurnal fluctuation, symptoms, and appearance), which required repair before further analyses. Six subscales contained items that did not contribute to a single trait measurement (multidimensional). All subscales were found to be inadequate at distinguishing between persons (person separation >2.0), and targeting of the questions to QoL was poor for six subscales. CONCLUSIONS The NEI-RQL-42 questionnaire is deficient for all psychometric properties tested. Clinicians or researchers wishing to measure QoL related to refractive error correction should consider other questionnaires that have been rigorously developed and meet standard psychometric properties.

Effect of Tear Hyperosmolarity and Signs of Clinical Ocular Surface Pathology upon Conjunctival Goblet Cell Function in the Human Ocular Surface

PURPOSE To investigate the effect of tear hyperosmolarity and signs of clinical ocular surface pathology on conjunctival goblet cell population. METHODS 111 participants were assessed using tear osmolarity (TO) measurements and a comprehensive selection of clinical ophthalmic tests. The resultant clinical database was assessed for evidence of patterns of composite increasing pathology. The total, filled, and empty goblet cell numbers were measured: total number of goblet cells as per cytokeratin 7 (CK7) immunofluorescence and number of filled goblet cells as per periodic acid Schiffs reagent (PAS) or lectin helix pomatia agglutinin (HPA). Goblet cell profile was correlated with composite clinical pathologic grades. RESULTS No significant correlation was found between TO and goblet cell number or function (as indicated by number of filled or unfilled goblet cells). Distinct composite clinical pathologic groups 0-IV with increasing pathology were created based on the frequency of positive pathologic signs, which adhered to the Dry Eye Workshop purported mechanism. Only in group IV was there significantly increased mean tear osmolarity of 344 mOsm/L (P < 0.000) along with significantly decreased empty goblet cell number (CK7+ and HPA-) compared to filled (CK7+ and HPA+, P = 0.000). When the number of filled goblet cells (PAS+) was analyzed there was significant increase in tear osmolarity for the two most severe grades; 3 and 4. CONCLUSIONS The goblet cell population does not appear to be affected by isolated tear hyperosmolarity. Hyperosmolarity when combined with other ocular surface pathology or inflammation alters the goblet cell population.

Staphylococcus aureus Activates the NLRP3 Inflammasome in Human and Rat Conjunctival Goblet Cells

The conjunctiva is a moist mucosal membrane that is constantly exposed to an array of potential pathogens and triggers of inflammation. The NACHT, leucine rich repeat (LRR), and pyrin domain-containing protein 3 (NLRP3) is a Nod-like receptor that can sense pathogens or other triggers, and is highly expressed in wet mucosal membranes. NLRP3 is a member of the multi-protein complex termed the NLRP3 inflammasome that activates the caspase 1 pathway, inducing the secretion of biologically active IL-1β, a major initiator and promoter of inflammation. The purpose of this study was to: (1) determine whether NLRP3 is expressed in the conjunctiva and (2) determine whether goblet cells specifically contribute to innate mediated inflammation via secretion of IL-1β. We report that the receptors known to be involved in the priming and activation of the NLRP3 inflammasome, the purinergic receptors P2X4 and P2X7 and the bacterial Toll-like receptor 2 are present and functional in conjunctival goblet cells. Toxin-containing Staphylococcus aureus (S. aureus), which activates the NLRP3 inflammasome, increased the expression of the inflammasome proteins NLRP3, ASC and pro- and mature caspase 1 in conjunctival goblet cells. The biologically active form of IL-1β was detected in goblet cell culture supernatants in response to S. aureus, which was reduced when the cells were treated with the caspase 1 inhibitor Z-YVAD. We conclude that the NLRP3 inflammasome components are present in conjunctival goblet cells. The NRLP3 inflammasome appears to be activated in conjunctival goblet cells by toxin-containing S. aureus via the caspase 1 pathway to secrete mature IL1-β. Thus goblet cells contribute to the innate immune response in the conjunctiva by activation of the NLRP3 inflammasome.

Mathematics of Zernike Polynomials: A Review

Monochromatic aberrations of the eye principally originate from the cornea and the crystalline lens. Aberrometers operate via differing principles but function by either analysing the reflected wavefront from the retina or by analysing an image on the retina. Aberrations may be described as lower order or higher order aberrations with Zernike polynomials being the most commonly employed fitting method. The complex mathematical aspects with regards the Zernike polynomial expansion series are detailed in this review. Refractive surgery has been a key clinical application of aberrometers; however, more recently aberrometers have been used in a range of other areas ophthalmology including corneal diseases, cataract and retinal imaging.

Visual and refractive outcomes following myopic laser-assisted subepithelial keratectomy with a flying-spot excimer laser

PURPOSE: To investigate the visual and refractive outcomes following laser‐assisted subepithelial keratectomy (LASEK) surgery with a flying‐spot excimer laser. SETTING: Private practice, Ireland. DESIGN: Case series. METHODS: In this prospective study, the mean manifest spherical equivalent (SE), sphere, and cylinder were measured preoperatively. All eyes had LASEK surgery with an aberration‐free algorithm with the Schwind Amaris excimer laser. Outcomes measured at 1 month, 6 months, and 1 year were uncorrected distance visual acuity (UDVA), manifest refraction, corrected distance visual acuity, contrast sensitivity, aberrometry, and complications. Accuracy, efficacy, and safety were evaluated at 1 year. RESULTS: Preoperatively, the mean SE, sphere, and cylinder in the 80 eyes (48 patients) were −3.58 diopters (D) ± 2.00 (SD), −3.23 ± 1.93 D, and −0.85 ± 0.65 D, respectively. One year postoperatively, the mean SE was −0.00 ± 0.22 D; 57 eyes (71%) were within −0.13 to +0.13 D of the SE, and 71 eyes (98%) were within ±0.50 D. The mean UDVA was −0.06 ± 0.07 logMAR, with an efficacy index of 1.04. The postoperative SE was stable between 1 month, 3 months, and 1 year. One eye (1%) had a change in SE by more than 0.50 D at 6 months and 1 year. There were no statistically significant differences in any aberrations at 1 year. The contrast sensitivity improved from 1.66 ± 0.17 log units preoperatively to 1.72 ± 0.15 log units at 1 month postoperatively (P=.0003), which was unchanged at 6 months and 1 year. CONCLUSION: This study demonstrated the effectiveness of LASEK for the treatment of myopia with this flying‐spot excimer laser. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Hyperopic LASEK treatments with mitomycin C using the SCHWIND AMARIS.

PURPOSE To investigate the outcomes of hyperopic laser epithelial keratomileusis (LASEK) with mitomycin C (MMC) using the SCHWIND AMARIS platform. METHODS Prospective study of 28 eyes of 14 patients. Mean preoperative manifest spherical equivalent refraction was +2.71±0.72 diopters (D) (range: +1.50 to +4.50 D). All eyes underwent LASEK with an Aberration-Free™ algorithm with the SCHWIND AMARIS followed by a 35-second application of MMC with a 6.7-mm optical zone size. RESULTS At 1 year, mean manifest spherical equivalent refraction was 0.03±0.30 D (range: -0.53 to +0.50 D), with 13 eyes within -0.13 to +0.13 D and all 28 eyes within ±0.50 D. Mean uncorrected distance visual acuity was -0.03±0.09 logMAR, and the efficacy and safety indices were 1, respectively, at 1 year. The postoperative manifest spherical equivalent refraction was stable between 1 and 3 months and 1 year. CONCLUSIONS Hyperopic LASEK with MMC using the SCHWIND AMARIS provided good outcomes in terms of accuracy, efficacy, safety, and stability.