The Rule of Preoperative Pentacam Photographic Imaging for Optimizing Visual Outcome of Cataract Surgery
Ahmed Fouad Ahmed;
Abstract
The Pentacam is the first instrument to use a rotating Scheimpflug camera to take multiple images of the anterior segment and use these to generate three-dimensional images and calculate measurements of the eye that help in optimizing the outcome of cataract surgery as follows.
• The oculus pentacam is a multipurpose instrument that is capable of external ocular photography, corneal pachymetry, corneal topography, densitometry and anterior chamber analysis. The oculus pentacam provides the user with the ability to view, photograph and measure the anterior segment of the eye without invasive operation or direct contact with the eye.
• Pentacam topography is better than conventional topographer because the former is elevation based & not Placido disc based with showing an anterior & posterior elevation map in addition to curvature map to better analysis of the cornea.
• For calculating corneal thickness, the camera measures from the top of the epithelium to the anterior surface of the endothelium. Importantly, it does not measure the tear film. The corneal thickness is displayed as a color image and can be evaluated at any particular location by clicking on the area or by using the numerical function.
• Pentacam accurately measures the global corneal astigmatism, quantifies the nature of the astigmatism (i.e., symmetric ‘bow tie’ vs. asymmetric or ‘irregular’ astigmatism) and identifies the steep meridian of astigmatism and accordingly aids in the decision making for correction of astigmatism.
• In the “Holladay Report” incorporated in the Pentacam software the ratio between back and front power of the cornea is calculated for the current examination as well as the “Equivalent K-Readings” of the cornea.
• The Pentacam provides a comprehensive, precise and valid measurement of corneal power and optical aberrations that allows the ophthalmologist to make better decisions regarding the intraocular lens design and power, particularly in cases with abnormal corneas, either from ecstatic conditions or previous keratorefractive surgery. The measurement obtained from the Pentacam in abnormal corneas should be used in combination with formulas designed for this particular instrument.
• Opacification of the crystalline lens can be quantitatively imaged and analyzed using the Pentacam. The grading of lens density through Scheimpflug images has been found to correlate well with the Lens Opacification Classification System (LOCS) III grading system for cataracts. This densitometry helps in choosing the power modality during phacoemulsification. It is also excellent tool for identifying intralenticular foreign bodies.
• The Pentacam is useful in assessment of post cataract surgery patients as in cases of posterior capsular opacification (PCO) and intraocular lens dislocation. Another interesting application is in diagnosing Capsular Bag Distension Syndrome.
• The oculus pentacam is a multipurpose instrument that is capable of external ocular photography, corneal pachymetry, corneal topography, densitometry and anterior chamber analysis. The oculus pentacam provides the user with the ability to view, photograph and measure the anterior segment of the eye without invasive operation or direct contact with the eye.
• Pentacam topography is better than conventional topographer because the former is elevation based & not Placido disc based with showing an anterior & posterior elevation map in addition to curvature map to better analysis of the cornea.
• For calculating corneal thickness, the camera measures from the top of the epithelium to the anterior surface of the endothelium. Importantly, it does not measure the tear film. The corneal thickness is displayed as a color image and can be evaluated at any particular location by clicking on the area or by using the numerical function.
• Pentacam accurately measures the global corneal astigmatism, quantifies the nature of the astigmatism (i.e., symmetric ‘bow tie’ vs. asymmetric or ‘irregular’ astigmatism) and identifies the steep meridian of astigmatism and accordingly aids in the decision making for correction of astigmatism.
• In the “Holladay Report” incorporated in the Pentacam software the ratio between back and front power of the cornea is calculated for the current examination as well as the “Equivalent K-Readings” of the cornea.
• The Pentacam provides a comprehensive, precise and valid measurement of corneal power and optical aberrations that allows the ophthalmologist to make better decisions regarding the intraocular lens design and power, particularly in cases with abnormal corneas, either from ecstatic conditions or previous keratorefractive surgery. The measurement obtained from the Pentacam in abnormal corneas should be used in combination with formulas designed for this particular instrument.
• Opacification of the crystalline lens can be quantitatively imaged and analyzed using the Pentacam. The grading of lens density through Scheimpflug images has been found to correlate well with the Lens Opacification Classification System (LOCS) III grading system for cataracts. This densitometry helps in choosing the power modality during phacoemulsification. It is also excellent tool for identifying intralenticular foreign bodies.
• The Pentacam is useful in assessment of post cataract surgery patients as in cases of posterior capsular opacification (PCO) and intraocular lens dislocation. Another interesting application is in diagnosing Capsular Bag Distension Syndrome.
Other data
| Title | The Rule of Preoperative Pentacam Photographic Imaging for Optimizing Visual Outcome of Cataract Surgery | Other Titles | التصوير الفوتوغرافى بالكاميرا الخماسية لتحسين حدة الإبصار لجراحة المياه البيضاء | Authors | Ahmed Fouad Ahmed | Issue Date | 2014 |
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