Mayank A. Nanavaty

Analysis of patients with good uncorrected distance and near vision after monofocal intraocular lens implantation

PURPOSE: To analyze factors contributing to uncorrected visual acuity of at least 6/12 for distance and at least J4 for near (pseudoaccommodation) after monofocal intraocular lens (IOL) implantation. SETTING: Iladevi Cataract and IOL Research Center, Ahmedabad, India. METHODS: In a case‐controlled study of 30 eyes (30 patients) that had phacoemulsification, those with pseudoaccommodation were assigned to cases and 30 eyes (30 patients) without pseudoaccommodation were designated as controls. Controls were matched by identical best corrected visual acuity, age, and postoperative duration. Subjective refraction was done with retinoscopy. Factors analyzed included corneal astigmatism, pupil size, axial IOL movement, amplitude of accommodation, axial length (AL), and age. Corneal astigmatism was noted on topography and interpreted as against the rule (ATR) (180 ± 15 degrees), with the rule (WTR) (90 ± 15 degrees), and oblique (OB) (45/135 ± 30 degrees). Pupil size was noted on topographic display and AL and anterior chamber depth (ACD) on immersion A‐scan. The axial IOL movement was calculated as the difference in ACD after instillation of cyclopentolate 1% (Cyclopent) and subsequently pilocarpine nitrate 2% (Carpinol) at separate visits, and amplitude of accommodation was measured with static and dynamic retinoscopy. Multivariate logistic regression and odds ratio with 95% confidence intervals were determined. RESULTS: Mean spherical equivalent was −0.45 ± 0.63 diopter (D) in cases and −0.35 ± 0.83 D (P = .61) in controls. Multivariate logistic regression in cases versus controls: corneal astigmatism (ATR versus WTR and OB collectively): 10.19 [1.8,57.44], P = .009; pupil size: 0.45 [0.07,2.71], P = .38; axial IOL movement: 1.39 [0.51,0.77], P = .514; amplitude of accommodation: 2.95 [0.93,9.3], P = .065; AL: 0.55 [0.29,1.02], P = .058; and age: 0.98 [0.5,1.95], P = .963. CONCLUSION: The study suggests a significant role of ATR corneal astigmatism in good uncorrected distance and near vision after monofocal IOL implantation.

Outcomes of pseudophakic toric intraocular lens implantation in Keratoconic eyes with cataract.

PURPOSE To evaluate the outcomes of pseudophakic toric intraocular lens (IOL) implantation in eyes with stable keratoconus and cataract. METHODS Retrospective, noncomparative, case series of 12 eyes from 9 patients (mean age: 63.4±3.5 years) with stable mild to moderate keratoconus and cataract who underwent pseudophakic toric IOL implantation (AT TORBI 709M, AcriTec). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, keratometric findings, adverse events, and postoperative complications were recorded for all eyes. RESULTS Mean postoperative follow-up was 9.0+8.8 months. At last postoperative follow-up, UDVA was 20/40 or better in 75% and CDVA was 20/40 or better in 83.3% of eyes. Postoperative mean refractive sphere (pre- vs postoperative: -4.80±5.60 vs 0.30±0.50 diopters [D]) and cylinder (pre- vs postoperative: 3.00+1.00 D vs 0.70+0.80 D) were significantly better (P<.01 for both). No intra- or postoperative complications occurred. No eyes had progression of keratoconus or significant IOL rotation at postoperative follow-up. CONCLUSIONS Pseudophakic toric IOLs are an effective option and provide good vision in eyes with stable mild to moderate keratoconus and cataract.

Effect of trypan blue staining on the density and viability of lens epithelial cells in white cataract

PURPOSE: To assess the effect of anterior capsule staining with trypan blue 0.0125% on the density and viability of the lens epithelial cells (LECs). SETTING: Iladevi Cataract and IOL Research Center, Ahmedabad, India. METHODS: This randomized prospective study comprised 40 eyes having phacoemulsification for white mature cataract. Patients were randomized to have the anterior capsule stained with 0.1 mL trypan blue 0.0125% solution before the anterior capsulorhexis (Group 1, n = 20) or to have no anterior capsule staining before the anterior capsulorhexis (Group 2, n = 20). The density and viability of LECs were analyzed. The first 20 samples (10 from Group 1, 10 from Group 2) were stained with hematoxylin–eosin for cell density analysis using image‐analysis software. The remaining 20 samples (10 from each group) were stained with a solution containing 0.5 μM calcein AM and 5 μM propidium iodide for 10 minutes at 37°C for viability assay. RESULTS: The mean cell density in Group 1 (with staining) was 3533.15 cells/mm2 ± 664.01 (SD). This was significantly lower than the mean of 4235.59 ± 414.93 cells/mm2 in Group 2 (no staining) (P = .01). The mean capsule area covered with LECs (80.75% ± 8.04% versus 94.63% ± 3.78%) and the mean live LECs in the covered area (51.69% ± 11.54% versus 68.67% ± 9.15%) were also significantly lower in Group 1 (P = .002). CONCLUSION: Staining the anterior capsule with trypan blue affected the density and viability of LECs.

Effect of hydrodissection alone and hydrodissection combined with rotation on lens epithelial cells: Surgical approach for the prevention of posterior capsule opacification

PURPOSE: To evaluate the impact of corticocleaving hydrodissection alone and hydrodissection combined with rotation on lens epithelial cells (LECs) and residual cortical fibers (RCFs). SETTING: Iladevi Cataract and IOL Research Center, Ahmedabad, India. METHODS: An experimental laboratory study of 20 fresh human cadaver eyes (10 pairs) was conducted. A single eye from each pair was assigned to the control group, in which no hydrodissection and no rotation were performed (control). The other eye was randomized to corticocleaving hydrodissection alone (Group 1) or corticocleaving hydrodissection with rotation (Group 2). Cataract extraction was standardized. Capsule polishing was omitted. Area of LEC loss (%) in the preequatorial zone (PZ) and equatorial zone (EZ) was calculated as: [Area of capsule without cells/Total area of capsule] × 100. Area of presence of RCFs (%) was calculated as: [Circumference of EZ of capsule with RCF/Total circumference of EZ of the capsule] × 100. The Mann‐Whitney U and the Wilcoxon signed rank tests were applied. RESULTS: In the control group, area of cell loss (%) was 3.9 ± 3.2 in the PZ and 2.7 ± 0.8 in the EZ; presence of RCFs (%) was 83.8 ± 1.7. Area of LEC loss (%) in Groups 1 and 2 was 24.8 ± 4.5 and 42.6 ± 5.4 (P = .008) in the PZ and 22.4 ± 2.1 and 54 ± 2.5 (P = .008) in the EZ, respectively. Area of presence of RCFs (%) in Groups 1 and 2 was 34.2 ± 3.7 and 23.7 ± 3.7 (P = .008), respectively. CONCLUSION: Corticocleaving hydrodissection combined with rotation removed significant quantities of LECs and RCFs.

Safety and efficacy of epithelium removal and transepithelial corneal collagen crosslinking for keratoconus

This review aims to assess the efficacy and safety of epithelial removal (ER) and transepithelial (TE) corneal collagen crosslinking (CXL) for the treatment of keratoconus. We used MEDLINE to identify all ER and TE CXL studies on keratoconic eyes (n≥20, follow-up ≥12 months). Ex vivo and studies for non-keratoconus indications or in conjunction with other procedures were excluded. Data on uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refractive cylinder, maximum keratometry (Kmax), and adverse events were collected at the latest follow-up and 1 year. Only one randomised controlled trial (RCT) qualified inclusion. Forty-four ER and five TE studies were included. For logMAR UDVA, CDVA, mean spherical equivalent, refractive cylinder and Kmax, at latest follow-up 81, 85, 93, 62, and 93% ER studies vs 66.7, 80, 75, 33, and 40% TE studies reported improvement, respectively. Whereas at 1 year, 90, 59, and 91% ER studies vs 80, 50, and 25% TE studies reported improvement, respectively. The majority of studies showed reduced pachymetry in both groups. Treatment failure, retreatment rates, and conversion to transplantation were reported to be up to 33, 8.6, and 6.25%, respectively, in ER studies only. Stromal oedema, haze, keratitis, and scarring were only reported in ER studies, whereas endothelial cell counts remained variable in both groups. Both ER and TE studies showed improvement in visual acuity, refractive cylinder but Kmax worsened in most TE studies. Adverse events were reported more with ER studies. This review calls for more high quality ER and TE studies with comparable parameters for further assessment of safety and efficacy.

AcrySof Natural SN60AT versus AcrySof SA60AT intraocular lens in patients with color vision defects.

PURPOSE: To determine whether implantation of the AcrySof Natural intraocular lens (IOL) worsened the severity of existing color deficit in congenital partial red–green color deficient individuals (CPRG). METHODS: A prospective controlled randomized double‐masked analysis of 30 consecutive patients with CPRG defect and bilateral cataracts received a Natural IOL (test group) in 1 eye and a single‐piece AcrySof IOL (control group) in the other eye. Patients were tested unilaterally to detect CPRG defect using Ishihara pseudoisochromatic plates and the Farnsworth D‐15 test. Plates 1 to 21 measured the Ishihara error score; plates 22 to 25 indicated severity of defect based on clarity of both numerals as partial mild/moderate (both visible), partial severe defect (only 1 visible). The D‐15 test is based on number of diametrical crossings on the circular diagram; severity is graded as mild (1 crossing), moderate (2 crossings), or severe (>2 crossings). Tests were performed before and after IOL implantation at 1, 3, and 6 months. At mean follow‐up of 6.13 months ± 1.2 (SD), analysis of variance test judged the difference in error scores and cross tabulation represented change in number of diametrical crossings. RESULTS: The mean age was 62.3 ± 8.5 years. All patients were men. Before IOL implantation, all patients had moderate CPRG defect on both tests. The Ishihara error score in the test and control groups did not reveal statistically significant differences (P = .505 and P = .119, respectively). With D‐15, none of the patients in the test or control group showed >2 crossings. CONCLUSION: The implantation of AcrySof Natural IOL did not worsen the preexisting severity of color defect in CPRG individuals.

Translenticular hydrodissection, lens fragmentation, and influence on ultrasound power in femtosecond laser–assisted cataract surgery and refractive lens exchange

Purpose To compare ultrasound time (UST) during femtosecond laser–assisted and conventional cataract surgery or refractive lens exchange and evaluate UST during femtosecond laser surgery with and without a new technique, translenticular hydrodissection. Setting Centre for Sight, East Grinstead, West Sussex, United Kingdom. Design Comparative case series. Method This single‐surgeon study compared consecutive femtosecond laser–assisted surgery (with and without translenticular hydrodissection to assist lens mobilization) and consecutive conventional surgery performed immediately before adoption of femtosecond laser technology. The mean US power, UST, and effective phacoemulsification time (EPT) in the 2 groups were compared. Further analysis of the femtosecond group compared translenticular hydrodissection and no translenticular hydrodissection. Results The mean US power, UST, and EPT were significantly longer in the conventional group (n = 108) than in the femtosecond group (n = 108) as follows: 7.30% ± 2.56% (SD) versus 5.32% ± 2.48% (P=.000); 9.89 ± 5.32 seconds versus 8.58 ± 4.66 seconds (P=.044); 0.87 ± 0.85 seconds versus 0.57 ± 0.51 seconds (P=.002), respectively. In the femtosecond group, parameters were significantly higher in eyes without translenticular hydrodissection (n = 27) than in eyes with translenticular hydrodissection (n = 81) as follows: 5.78% ± 2.23% versus 5.16% ± 2.56% (P=.046); 10.95 ± 4.66 seconds versus 7.78 ± 4.41 seconds (P=.046); 0.72 ± 0.26 seconds versus 0.52 ± 0.53 seconds (P=.002), respectively. Conclusion Femtosecond laser capsulotomy and lens fragmentation statistically significantly reduced UST over conventional surgery. Translenticular hydrodissection further reduced UST. Financial Disclosure Dr. Daya is a consultant to Bausch & Lomb and Technolas Perfect Vision GmbH. No author has a financial or proprietary interest in any material or method mentioned.

Use of the Double-Pass Technique to Quantify Ocular Scatter in Patients with Uveitis: A Pilot Study

Purpose: To assess whether the double-pass technique can be employed to quantify the amount of light scattering in patients with uveitis. Methods: 56 eyes of 44 patients with intraocular inflammation were consecutively recruited from the uveitis clinic over 9 months. The degree of intraocular inflammation was recorded according to the Standardization of Uveitis Nomenclature criteria and the eyes were grouped as having anterior, intermediate, posterior or panuveitis. Objective scatter index (OSI) was assessed using a double-pass technique with the Optical Quality Analysis System II. Results: Twenty-four eyes had anterior uveitis, 9 eyes had intermediate uveitis, 10 eyes had posterior uveitis and 13 eyes had panuveitis. The OSI was significantly different between all 4 groups (p = 0.0005). The mean OSI was highest in eyes with anterior uveitis (2.6 ± 3.1) and lowest in posterior uveitis (1.9 ± 1.3). Anterior chamber cells significantly correlated with OSI (R2 = 0.8726, p = 0.007), unlike posterior chamber cells (R2 = 0.0189, p = 0.588) and flare (R2 = 0.0048, p = 0.471). Conclusion: Patients with anterior uveitis have more ocular scatter, and anterior chamber cells scatter more light. This pilot study opens new avenues for research in use of the double-pass technique to assess light scattering in uveitis.

Perioperative antibiotic prophylaxis during phaco-emulsification and intraocular lens implantation: national survey of smaller eye units in England.

Purpose:  To evaluate the commonest routinely used perioperative antibiotic, the preferred route of administration and the choice of antibiotic in ‘penicillin allergy’ by consultant ophthalmic surgeons in England. Methods:  A postal survey was conducted, between December 2008 and April 2009, among consultant ophthalmic surgeons working in smaller National Health Service Ophthalmic departments in England. Smaller units were defined by having a maximum of eight consultant surgeons and tend to be based in district general hospitals. The questionnaires were sent to all consultant ophthalmic surgeons irrespective of special interests. The three questions asked were: (i) Which antibiotic(s) do you use routinely for phaco-emulsification and intraocular lens implantation? (ii) What is your usual route of administration? and (iii) Which antibiotic(s) do you use when the patient states that they have ‘penicillin allergy’? Results:  The questionnaire was sent to 401 consultant ophthalmic surgeons and 262 consultants (65.34%) replied. Further analysis showed, 44.7% used only intracameral cefuroxime, 31.7% used only subconjunctival cefuroxime, 2.3% used only subconjunctival gentamicin, 6.9% used subconjunctival gentamicin or cefuroxime, 0.4% used subconjunctival cefotaxime, 0.4% used subconjunctival ceftazidime and 0.8% used no antibiotic prophylaxis. One hundred and three (37%) used cefuroxime in patients allergic to penicillin and 47% switched to gentamicin in this situation. Conclusion:  Routine phaco-emulsification and intraocular lens implantation is the commonest elective surgical procedure undertaken in the National Health Service and yet there is a wide variation in the use of prophylactic antibiotics in patients with or without ‘penicillin allergy’ despite The European Society of Cataract and Refractive Surgeons recommendations in 2007. Less than half of the surgeons working in smaller ophthalmic units routinely used intracameral cefuroxime and in ‘penicillin allergy’ only one-third used cefuroxime. This survey highlights the reluctance of using cefuroxime in patients allergic to penicillin despite evidence to the contrary.Purpose:  To evaluate the commonest routinely used perioperative antibiotic, the preferred route of administration and the choice of antibiotic in ‘penicillin allergy’ by consultant ophthalmic surgeons in England.

Sterile keratitis after combined riboflavin-UVA corneal collagen cross-linking for keratoconus

PurposeTo investigate patient risk factors and to look for potential causes of sterile infiltrates following an unexpected cluster of sterile keratitis after a routine collagen cross-linking (CXL) list.MethodsThe records of all 148 cases of CXL were reviewed retrospectively. The equipment and solutions used and our clinic’s standard operating procedure for CXL were reviewed. An in-vitro experiment to explore the variation in ultraviolet A (UVA) irradiance from fluctuations in the working distance of the UVA lamp was conducted.ResultsThe four patients who developed sterile infiltrates had steeper maximum corneal curvatures (68.0±7.3 D) and thinner pachymetry (389.9±49.0 μm) than the 144 who did not (57.0±8.2 D, P=0.05; 454.6±45.4 μm, P=0.08). A corneal curvature of >60 Dand a pachymetry of <425 μm were significant risk factors. All four affected cases obtained a complete resolution with topical antibiotics and steroids. The unaided VA and the maximum K improved from their pre-operative levels in three out of four patients. A 2-mm reduction in distance of the VEGA C.B.M. X-Linker from a treated surface increased irradiance to 3.5–3.7 mW/cm2, which is above the threshold for endothelial toxicity.ConclusionPatients with thinner and steeper corneas are at an increased risk of developing sterile keratitis. The visual outcomes despite this complication are good.