Sanjay Mantry

Corneal pachymetry in normal and keratoconic eyes: Orbscan II versus ultrasound

Purpose: To compare corneal thickness measurements using Orbscan II (OII) and ultrasonic (US) pachymetry in normal and in keratoconic eyes. Setting: Eye Department, Heartlands and Solihull NHS Trust, Birmingham, United Kingdom. Methods: Central corneal thickness (CCT) was measured by means of OII and US pachymetry in 1 eye of 72 normal subjects and 36 keratoconus patients. The apical corneal thickness (ACT) in keratoconus patients was also evaluated using each method. The mean of the difference, standard deviation (SD), and 95% limits of agreement (LoA = mean ± 2 SD), with and without applying the default linear correction factor (LCF), were determined for each sample. The Student t test was used to identify significant differences between methods, and the correlation between methods was determined using the Pearson bivariate correlation. Bland‐Altman analysis was performed to confirm that the results of the 2 instruments were clinically comparable. Results: In normal eyes, the mean difference (± 95% LoA) in CCT was 1.04 &mgr;m ± 68.52 (SD) (P>.05; r = 0.71) when the LCF was used and 46.73 ± 75.40 &mgr;m (P = .0001; r = 0.71) without the LCF. In keratoconus patients, the mean difference (± 95% LoA) in CCT between methods was 42.46 ± 66.56 &mgr;m (P<.0001: r = 0.85) with the LCF, and 2.51 ± 73.00 &mgr;m (P>.05: r = 0.85) without the LCF. The mean difference (± 95% LoA) in ACT for this group was 49.24 ± 60.88 &mgr;m (P<.0001: r = 0.89) with the LCF and 12.71 ± 68.14 &mgr;m (P = .0077; r = 0.89) when the LCF was not used. Conclusions: This study suggests that OII and US pachymetry provide similar readings for CCT in normal subjects when an LCF is used. In keratoconus patients, OII provides a valid clinical tool for the noninvasive assessment of CCT when the LCF is not applied.

Ocular response analyser to assess hysteresis and corneal resistance factor in low tension, open angle glaucoma and ocular hypertension

Purpose:  The aim of this study is to compare the hysteresis and corneal resistance factor (CRF) in normal tension glaucoma (NTG), primary open angle glaucoma (POAG) and ocular hypertension (OHT) eyes measured by the ocular response analyser (ORA).

Subjective and objective performance of the Lenstec KH-3500 "accommodative" intraocular lens

Aim: To determine whether eyes implanted with the Lenstec KH-3500 “accommodative” intraocular lenses (IOLs) have improved subjective and objective focusing performance compared to a standard monofocal IOLs. Methods: 28 participants were implanted monocularly with a KH-3500 “accommodative” IOL and 20 controls with a Softec1 IOL. Outcome measures of refraction, visual acuity, subjective amplitude of accommodation, objective accommodative stimulus response curve, aberrometry, and Scheimpflug imaging were taken at ∼3 weeks and repeated after 6 months. Results: Best corrected acuity with the KH-3500 was 0.06 (SD 0.13) logMAR at distance and 0.58 (0.20) logMAR at near. Accommodation was 0.39 (0.53) D measured objectively and 3.1 (1.6) D subjectively. Higher order aberrations were 0.87 (0.85) μm and lower order were 0.24 (0.39) μm. Posterior subcapsular light scatter was 0.95% (1.37%) greater than IOL clarity. In comparison, all control group measures were similar except objective (0.17 (0.13) D; p = 0.032) and subjective (2.0 (0.9) D; p = 0.009) amplitude of accommodation. Six months following surgery, posterior subcapsular scatter had increased (p<0.01) in the KH-3500 implanted subjects and near word acuity had decreased (p<0.05). Conclusions: The objective accommodating effects of the KH-3500 IOL appear to be limited, although the subjective and objective accommodative range is significantly increased compared to control subjects implanted with conventional IOLs. However, this “accommodative” ability of the lens appears to have decreased by 6 months post-surgery.

Nidek OPD-scan analysis of normal, keratoconic, and penetrating keratoplasty eyes

PURPOSE To determine by wavefront analysis the difference between eyes considered normal, eyes diagnosed with keratoconus, and eyes that have undergone penetrating keratoplasty METHODS The Nidek OPD-Scan wavefront aberrometer was used to measure ocular aberrations out to the sixth Zernike order. One hundred and thirty eyes that were free of ocular pathology, 41 eyes diagnosed with keratoconus, and 8 eyes that had undergone penetrating keratoplasty were compared for differences in root mean square value. Three and five millimeter root mean square values of the refractive power aberrometry maps of the three classes of eyes were compared. Radially symmetric and irregular higher order aberration values were compared for differences in magnitude. RESULTS Root mean square values were lower in eyes free of ocular pathology compared to eyes with keratoconus and eyes that had undergone penetrating keratoplasty. The aberrations were larger with the 5-mm pupil. Coma and spherical aberration values were lower in normal eyes. CONCLUSION Wavefront aberrometry of normal, pathological, and eyes after surgery may help to explain the visual distortions encountered by patients. The ability to measure highly aberrated eyes allows an objective assessment of the optical consequences of ocular pathology and surgery. The Nidek OPD-Scan can be used in areas other than refractive surgery.

Combined amniotic membrane transplant and anterior stromal puncture in painful bullous keratopathy: clinical outcome and confocal microscopy.

OBJECTIVE To report the outcomes of anterior stromal micropuncture (ASP) combined with amniotic membrane transplantation (AMT) in the management of painful bullous keratopathy (BK) with poor visual potential, and to assess amniotic membrane (AM) retention. DESIGN Case series, retrospective review. PARTICIPANTS Twelve eyes of 12 patients with BK causing intractable pain or discomfort and poor visual potential, treated between March 2006 and October 2008 at Gartnavel General Hospital, Glasgow. METHODS Epithelial debridement was followed by ASP and the amniotic membrane was stabilized with a purse-string 10/0 nylon corneal suture and a bandage contact lens. During a mean follow-up of 67 weeks (range, 27-139 weeks), pain relief, epithelial healing, visual changes, confocal microscopy, and appearance of new bullae were evaluated. Success was defined as complete resolution or significant improvement in pain. RESULTS Twelve eyes of 12 patients, mean age 61 years (range, 40-88 years), were identified. Corneal epithelial healing was complete in 11 eyes 1 month postoperatively. Pain and conjunctival inflammation resolved in 11 patients (91.67%) and improved from severe to mild in the remaining patient. Incorporation of the AMT was observed on slit-lamp biomicroscopy in all eyes and was confirmed using confocal microscopy at final follow-up. CONCLUSIONS ASP combined with AMT is safe and effective, alleviates pain and discomfort, reduces ocular inflammation, and promotes epithelial healing and resolution of bullae in patients with BK with poor visual potential. There was long-term evidence of amniotic membrane graft retention in all eyes after the procedure, suggesting that ASP may improve the long-term retention rate of AM.

Delayed dislocation of an injectable hydrophilic acrylic lens after Nd:YAG capsulotomy in anterior capsular contraction syndrome

Posterior dislocation of IOLs has been reported following Nd:YAG laser for anterior capsule contraction in only 3 cases and these involved plate haptic silicone lenses; while the dislocation of IOLs into the vitreous cavity following posterior Nd:YAG laser capsulotomy have been reported in plate haptic silicone lenses and single piece hydrophilic acrylic (polymacon) lenses. We report a patient who suffered the delayed dislocation of an injectable hydrophilic acylic IOL (SlimFlex-m 123 IOL, PhysIOL, Liège, Belgium) following combined Nd:YAG laser anterior and posterior capsulotomy. We also explore the factors that may predispose to anterior capsular contraction syndrome and IOL dislocation.

Aspheric Ablation With the Nidek EC-5000 CX II With OPD-Scan Objective Analysis

PURPOSE To analyze the efficacy, predictability, stability, and safety of laser in situ keratomileusis (LASIK) to correct myopia and myopic astigmatism using the Nidek EC-5000 CX II laser and the Customized Aspheric Transition Zone (CATz) profile. METHODS We conducted a retrospective analysis of 100 eyes (50 patients) with myopic astigmatism. A CATz profile was used in all eyes (profile 4) with an ablation zone of 5 mm and a transition zone of 9 mm, using Nidek FinalFit software. RESULTS Average patient age was 39 years (range 21 to 69 yr). Preoperative mean spherical equivalent refraction was -4.70 +/- 2.53 D (range -11.88 to -0.50 D), mean preoperative sphere was -4.31 +/- 2.53 D (range -11.25 to -0.25 D), and mean preoperative cylinder was -0.78 +/- 0.69 D (range -3.25 to 0). Postoperative mean spherical equivalent refraction at 6 months was 0.12 +/- 0.53 D (range -1.63 to +0.88 D), mean postoperative sphere was 0.02 +/- 0.56 D (range -1.50 to +2.00 D), and mean postoperative cylinder was -0.29 +/- 0.50 D (range 0 to -1.75 D). Uncorrected visual acuity was 6/6 or better in 58% (58 eyes) and better than 6/12 in 93% (93 eyes). CONCLUSION LASIK with the Nidek EC-5000 CX II laser and the CATz profile was effective, reasonably predictable, stable, and safe for correction of myopic astigmatism with a spherical component between -0.25 and -11.25 D, and a cylindrical component up to 3.25 D, using the techniques in this study. Astigmatism was undercorrected with the current algorithm.

Correlation of Nidek OPD-Scan objective refraction with subjective refraction.

PURPOSE The aim of this study was to quantify how closely the Nidek OPD-Scan objective refraction correlated with subjective refraction. METHODS A retrospective audit of the preoperative refraction of 80 myopic and myopic astigmatic eyes before laser in situ keratomileusis (LASIK) or laser supepithelial keratomileusis (LASEK) was performed. Objective refraction in the 5-mm zone was performed using a Nidek OPD-Scan. Subjective refraction was performed by a senior optometrist. Statistical analysis of sphere, cylinder, and spherical equivalent refraction measurements was then performed. RESULTS Spherical measurements correlated well with a linear regression equation, with a correlation coefficient of 0.97. Cylinder measurements correlated less well, with a correlation coefficient of 0.85. Spherical equivalent refraction measurements correlated well, with a correlation coefficient of 0.97. Analyzing the numerical difference between each objective refraction and its corresponding subjective refraction, the majority of values were only 0.50 D apart for sphere, cylinder, and spherical equivalent refraction. CONCLUSION There was good correlation between objective OPD-Scan and subjective refraction, especially for sphere and spherical equivalent refraction measurements, with regression gradients and correlation coefficients close to 1.

Novel matrix ReGeneraTing Agent promotes rapid corneal wound healing.

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A case for single-use disposable corneal forceps: equipment reliability should be the primary concern

Disposable, single-use surgical instruments are increasingly being used to reduce cross-contamination and infection risks.1–3 Despite the hidden financial and environmental disposal costs, this approach avoids the problems associated with instrument damage during reprocessing. Cataract surgery already benefits from such disposable instruments.4 We wish to detail our experience with corneal forceps and graft management to highlight practical issues within the current financial climate. Currently, our instruments are sterilised off-site, with an anticipated 24 h turn around. A snapshot audit of all ophthalmic instruments available in the outpatients revealed numerous problems, including damaged instruments with non-opposing tips, incorrect labelling, instruments unidentifiable without opening of …