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Biomedical subjects

Sanjay Mantry

Publications and source records attributed to Sanjay Mantry.

10 recordsLinked to original sources
PubMed2006

The use of the Reichert ocular response analyser to establish the relationship between ocular hysteresis, corneal resistance factor and central corneal thickness in normal eyes.

PURPOSE: The aim of this study was to measure ocular hysteresis and corneal resistance factor (CRF), novel methods of analysing ocular rigidity/elasticity and to determine the relationship between central corneal thickness (CCT), hysteresis and CRF in normal subjects. DESIGN: Prospective, cross-sectional, clinical trial. PARTICIPANTS: The study included 207 normal eyes. METHODS: Hysteresis and CRF were measured by the ocular response analyser. The CCT was measured using a hand held ultrasonic pachymeter. MAIN OUTCOME MEASURES: Ocular hysteresis and CRF in normal patients and their relationship with CCT. RESULTS: The mean hysteresis was 10.7+/-2.0 mmHg standard deviation (S.D.) (range 6.1-17.6 mmHg); the mean CRF was 10.3+/-2.0 (range 5.7-17.1 mmHg). The mean CCT was 545.0+/-36.4 microm (471-650 microm). The relationship between hysteresis and CCT; CRF and CCT; CRF and hysteresis were significant (p<0.0001). CONCLUSION: This study demonstrated that corneal hysteresis increased with increasing CCT, however, the correlation was moderate. It would appear that CCT, hysteresis and CRF may measure different biomechanical aspects of ocular rigidity and are likely to be useful additional measurement to CCT in the assessment of ocular rigidity when measuring intraocular pressure (IOP). This may be of particular importance when trying to correct IOP measurements for increased or decreased ocular rigidity.

Adolescent↗
PubMed2006

Alcohol delamination of the corneal epithelium: an alternative in the management of recurrent corneal erosions.

PURPOSE: To investigate the efficacy of alcohol delamination in the management of recurrent corneal erosions (RCEs). DESIGN: Prospective single-center consecutive descriptive case series. PARTICIPANTS: Twelve patients with RCEs who did not respond to conservative management were treated with alcohol delamination. METHODS: A consecutive case series of 12 patients with RCEs who did not respond to conservative management were treated by alcohol delamination. A pain score was generated based on a visual analog scale of pain intensity. The duration of pain and frequency were also recorded. Patients were followed up at 1 week, 4 weeks, 3 months, 6 months, and 1 year and then at yearly intervals and monitored for recurrence of symptoms and corneal morphology. The removed epithelial sheet was examined by electron microscopy in 4 patients. INTERVENTION: The affected area of epithelium was peeled off after an application of 20% alcohol for 40 seconds under topical anesthesia. Eyes of patients were treated with an antibiotic and preservative-free artificial tear medication, and a bandage contact lens was inserted until epithelial healing was complete. MAIN OUTCOME MEASURES: Frequency of recurrence of erosions and duration and intensity of symptoms after alcohol delamination were studied. RESULTS: Eleven of the 12 eyes of patients had dramatic relief of symptoms over the follow-up period, ranging from 6 to 40 months. Eight patients were symptom free, and 1 patient had 2 mild symptom episodes in the first posttreatment month before becoming symptom free. The average follow-up period was 23.5 months. There were no residual effects from the application of alcohol noted in any patient. Electron microscopy of removed epithelium showed features of the underlying pathology. The separation of the epithelium occurred at the interface of the subepithelial abnormal deposit and the surface of Bowman's zone. CONCLUSION: Alcohol delamination appears to be a novel, simple, inexpensive treatment for RCEs. Unlike other methods, the removed epithelium is available as a sheet that may be subjected to further examination, though some of the changes observed may reflect the effect of alcohol on the epithelium.

Adult↗
PubMed2006

Objective accommodative amplitude and dynamics with the 1CU accommodative intraocular lens.

PURPOSE: To compare the objective accommodative amplitude and dynamics of eyes implanted with the one-compartment-unit (1CU; HumanOptics AG, Erlangen, Germany) accommodative intraocular lenses (IOLs) with that measured subjectively. METHODS: Twenty eyes with a 1CU accommodative IOL implanted were refracted and distance and near acuity measured with a logMAR (logarithm of the minimum angle of resolution) chart. The objective accommodative stimulus-response curve for static targets between 0.17 and 4.00 D accommodative demand was measured with the SRW-5000 (Shin-Nippon Commerce Inc., Tokyo, Japan) and PowerRefractor (PlusOptiX, Nürnberg, Germany) autorefractors. Continuous objective recording of dynamic accommodation was measured with the SRW-5000, with the subject viewing a target moving from 0 to 2.50 D at 0.3 Hz through a Badal lens system. Wavefront aberrometry measures (Zywave; Bausch & Lomb, Rochester, NY) were made through undilated pupils. Subjective amplitude of accommodation was measured with the RAF (Royal Air Force accommodation and vergence measurement) rule. RESULTS: Four months after implantation best-corrected acuity was -0.01 +/- 0.16 logMAR at distance and 0.60 +/- 0.09 logMAR at near. Objectively, the static amplitude of accommodation was 0.72 +/- 0.38 D. The average dynamic amplitude of accommodation was 0.71 +/- 0.47 D, with a lag behind the target of 0.50 +/- 0.48 seconds. Aberrometry showed a decrease in power of the lens-eye combination from the center to the periphery in all subjects (on average, -0.38 +/- 0.28 D/mm). Subjective amplitude of accommodation was 2.24 +/- 0.42 D. Two years after 1CU implantation, refractive error and distance visual acuity remained relatively stable, but near visual acuity, and the subjective and objective amplitudes of accommodation decreased. CONCLUSIONS: The objective accommodating effects of the 1CU lens appear to be limited, although patients are able to track a moving target. Subjective and objective accommodation was reduced at the 2-year follow-up. The greater subjective amplitude of accommodation is likely to result from the eye's depth of focus of and the aspheric nature of the IOL.

Accommodation, Ocular↗
PubMed2005

Scotopic measurement of normal pupil size with the Colvard pupillometer and the Nidek auto-refractor.

PURPOSE: To compare prospectively, pupil size with the Nidek AR700A auto-refractor and the Colvard pupillometer. METHODS: Pupil diameter was measured in 46 eyes at 2 min intervals in a low mesopic and under photopic light conditions. RESULTS: The mean pupil diameter was 4.8+/-1.0mm with the Colvard pupillometer and 4.8+/-0.9mm with the Nidek auto-refractor in low mesopic light conditions. The mean photopic pupil diameter was 3.3+/-0.8mm with the Colvard pupillometer and 3.9+/-0.8mm with the Nidek auto-refractor. CONCLUSION: The pupil sizes are very similar with both instruments.

Adult↗
PubMed2004

Surgical management of presbyopia.

Presbyopia is age-related reduction in amplitude of accommodation and the loss of the ability to change the eye's focus from far to near. It is the one of the most common age-related ailment. Traditional methods such as spectacle glasses or contact lenses are still the most widely used for correction of the problem. This article is an attempt to review the surgical options available for presbyopia.

Journal Article↗
PubMedDate not supplied

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.

Corneal Topography↗
PubMedDate not supplied

Higher order aberrations with aspheric ablations using the Nidek EC-5000 CX II laser.

PURPOSE: To analyze the change in higher order aberrations in myopic and myopic astigmatic eyes following an aspheric ablation profile for laser in situ keratomileusis (LASIK) using a Nidek EC-5000 CX II excimer laser system. METHODS: We performed a retrospective audit of 38 eyes (19 patients) with myopia and myopic astigmatism. A customized aspheric transition zone profile (CATz) was used in all eyes (profile 4) with an ablation zone of 5 mm and a transition zone of 9 mm using FinalFit software and a Nidek EC-5000 CX II excimer laser system. RESULTS: Mean higher order aberrations (RMS) increased from 0.42 microm at baseline to 0.57 microm at 6-month follow-up. Mean spherical aberrations (Z12) increased from 0.02 microm at baseline to 0.33 microm after LASIK. Mean spherical aberration defocus equivalent (DEQ) increased from 0.56 microm at baseline to 1.54 at 6 months after surgery. Mean trefoil (Z6) was -0.11 microm at baseline and -0.14 microm at the 3-month examination. Mean coma (Z7) was -0.09 microm at baseline and -0.10 microm after surgery. Mean coma (Z8) was -0.03 at baseline and 0 at the 3-month examination. Mean trefoil (Z9) was -0.03 at baseline and -0.12 at the 3-month examination. CONCLUSION: The amount of postoperative higher order aberrations in these myopic eyes was acceptable. However, the clinical significance of these numerical changes in aberrations is not known.

Adult↗
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

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.

Astigmatism↗