The Right Contact - Up to date information regarding contact lenses, Hyrid lenses, Soft lenses, button materials, gas permable lens and contact lens care products.
Presbyopic Contact Lenses: Bifocals and MultifocalsRabindraAdhikary
This document discusses presbyopic contact lenses and their history, principles, types, designs, fitting considerations, and tips for success. It provides an overview of bifocal contact lens options including simultaneous vision, alternating vision, monovision, multifocal, and non-refractive designs. Key aspects of the fitting process like determining the ideal candidate, measuring important parameters, and troubleshooting vision outcomes are summarized.
Multifocal contact lenses can correct both near and distance vision and are an alternative to bifocal glasses for people with active lifestyles. There are several types of multifocal contact lens designs, including soft, gas permeable, and hybrid lenses. The most common design is a diffractive lens with concentric circles of different optical powers. Multifocal contact lenses provide clear vision at multiple distances but may cause glare or hazy vision during adjustment. They also have advantages like less need for extra eyewear but disadvantages such as greater difficulty adapting to them.
Contact Lenses Management in PediatricsKaylie Ling
The post-surgical management of the pediatric aphakic is important. Contact lens is the best optical device in the post-operative aphakia to provide good visual quality.
Special contact lenses include:
Daily-wear lenses are removed nightly and replaced on an individualized schedule. Extended-wear lenses are worn overnight but removed at least weekly for cleaning. Disposable lenses are removed nightly and replaced daily, weekly, biweekly, or monthly.
Colored lenses change eye color appearance and circle lenses make the iris appear bigger, but over-the-counter colored contacts pose health risks. Toric lenses correct astigmatism but sometimes not as well as rigid gas permeable lenses. Bifocal or multifocal lenses correct nearsightedness, farsightedness, astigmatism, and presbyopia but visual quality is often not as good as
This document provides information on contact lenses, including their indications, contraindications, types, fitting procedures, parameters, complications, and special considerations. It discusses rigid gas permeable, soft, therapeutic, extended wear, disposable, and cosmetic contact lenses. Key details include the materials used to manufacture different contact lens types, advantages and disadvantages, fitting considerations like base curve and power, and potential post-fitting complications.
This document discusses different types of tinted contact lenses, including prosthetic, cosmetic, and visibility tints. Prosthetic tints are used to improve the appearance of a disfigured eye or help correct vision in a poorly functioning eye. Cosmetic tints are used to enhance or change eye color and come in transparent or opaque varieties. Visibility tints have a light blue or green tint to help with lens handling but do not affect eye color. Considerations for fitting and using tinted contact lenses include measuring iris diameter and determining tint requirements. Potential risks are similar to standard soft lenses and include toxic effects and corneal edema.
Spherical RGP contact lens fitting and prescribingPabita Dhungel
RGP contact lenses provide better oxygen permeability than soft lenses, making them a good option for higher prescriptions or conditions like keratoconus. Key factors in fitting RGP lenses include assessing the patient's cornea, measuring their prescription, pupil size, and lid characteristics to select the appropriate trial lens. During the fitting, the practitioner evaluates the lens's dynamic movement, static position, centration, and the patient's vision to determine the right lens parameters to order.
Scleral lens is a large rigid contact lens with a diameter range of 15mm to 25mm. Its resting point is beyond the
corneal borders, and are believed to be among the best vision correction options for irregular corneas. Wearing scleral lens also can postpone or even prevent surgical intervention as well as decrease the risk of corneal scarring.
Presbyopic Contact Lenses: Bifocals and MultifocalsRabindraAdhikary
This document discusses presbyopic contact lenses and their history, principles, types, designs, fitting considerations, and tips for success. It provides an overview of bifocal contact lens options including simultaneous vision, alternating vision, monovision, multifocal, and non-refractive designs. Key aspects of the fitting process like determining the ideal candidate, measuring important parameters, and troubleshooting vision outcomes are summarized.
Multifocal contact lenses can correct both near and distance vision and are an alternative to bifocal glasses for people with active lifestyles. There are several types of multifocal contact lens designs, including soft, gas permeable, and hybrid lenses. The most common design is a diffractive lens with concentric circles of different optical powers. Multifocal contact lenses provide clear vision at multiple distances but may cause glare or hazy vision during adjustment. They also have advantages like less need for extra eyewear but disadvantages such as greater difficulty adapting to them.
Contact Lenses Management in PediatricsKaylie Ling
The post-surgical management of the pediatric aphakic is important. Contact lens is the best optical device in the post-operative aphakia to provide good visual quality.
Special contact lenses include:
Daily-wear lenses are removed nightly and replaced on an individualized schedule. Extended-wear lenses are worn overnight but removed at least weekly for cleaning. Disposable lenses are removed nightly and replaced daily, weekly, biweekly, or monthly.
Colored lenses change eye color appearance and circle lenses make the iris appear bigger, but over-the-counter colored contacts pose health risks. Toric lenses correct astigmatism but sometimes not as well as rigid gas permeable lenses. Bifocal or multifocal lenses correct nearsightedness, farsightedness, astigmatism, and presbyopia but visual quality is often not as good as
This document provides information on contact lenses, including their indications, contraindications, types, fitting procedures, parameters, complications, and special considerations. It discusses rigid gas permeable, soft, therapeutic, extended wear, disposable, and cosmetic contact lenses. Key details include the materials used to manufacture different contact lens types, advantages and disadvantages, fitting considerations like base curve and power, and potential post-fitting complications.
This document discusses different types of tinted contact lenses, including prosthetic, cosmetic, and visibility tints. Prosthetic tints are used to improve the appearance of a disfigured eye or help correct vision in a poorly functioning eye. Cosmetic tints are used to enhance or change eye color and come in transparent or opaque varieties. Visibility tints have a light blue or green tint to help with lens handling but do not affect eye color. Considerations for fitting and using tinted contact lenses include measuring iris diameter and determining tint requirements. Potential risks are similar to standard soft lenses and include toxic effects and corneal edema.
Spherical RGP contact lens fitting and prescribingPabita Dhungel
RGP contact lenses provide better oxygen permeability than soft lenses, making them a good option for higher prescriptions or conditions like keratoconus. Key factors in fitting RGP lenses include assessing the patient's cornea, measuring their prescription, pupil size, and lid characteristics to select the appropriate trial lens. During the fitting, the practitioner evaluates the lens's dynamic movement, static position, centration, and the patient's vision to determine the right lens parameters to order.
Scleral lens is a large rigid contact lens with a diameter range of 15mm to 25mm. Its resting point is beyond the
corneal borders, and are believed to be among the best vision correction options for irregular corneas. Wearing scleral lens also can postpone or even prevent surgical intervention as well as decrease the risk of corneal scarring.
The document summarizes key aspects of contact lens fitting and evaluation. It discusses the anatomy relevant to contact lenses including the tear film and cornea. It then covers common contact lens materials and parameters like oxygen permeability. The document outlines a typical contact lens examination including case history, fitting evaluation, and patient education on proper lens care.
This document provides information about contact lenses, including their specifications, types, uses, and complications. It defines a contact lens as an artificial device that substitutes for the front surface of the cornea to correct refractive errors and corneal irregularities. The main types discussed are hard, rigid gas permeable, and soft lenses. Uses include optical correction as well as therapeutic, preventative, diagnostic, operative, cosmetic, and occupational indications. Complications that can occur involve the eyelids, conjunctiva, and cornea. Contraindications for contact lens use include certain eye diseases and conditions.
This document discusses therapeutic contact lenses (TCLs). It defines TCLs as lenses fitted to maintain or restore ocular tissues. The main aims of TCLs are relief of pain, promotion of healing, mechanical protection, maintenance of hydration, and drug delivery. The document describes various TCL types and their applications for conditions like corneal ulcers, dry eye, trauma, surgery recovery, and more. Complications are also addressed. In summary, it provides an overview of TCLs, including their definition, aims, types, fitting considerations, and clinical applications.
This document discusses paediatric contact lens fitting, including indications for use such as aphakia, pseudophakia, and refractive errors. It covers lens selection considerations like silicone hydrogel and silicone elastomer soft lenses as well as rigid lenses. Examination techniques are outlined, focusing on special approaches needed for babies and young children. Factors specific to fitting soft lenses, silicone rubber lenses, and rigid lenses in paediatric patients are also described.
This document provides an overview of contact lenses, including their history, uses, types, fitting parameters, and indications/contraindications. Some key points:
- The first contact lenses were developed in the late 1800s but were uncomfortable scleral lenses. Modern soft and rigid gas permeable lenses emerged later.
- Contact lenses are used for vision correction, therapy, prevention of eye issues, diagnosis, surgery assistance, cosmetic purposes, and occupations like sports or acting.
- Lens types include soft hydrogel lenses, silicone hydrogel lenses, rigid gas permeable lenses, and the now obsolete hard PMMA lenses. Parameters like material, diameter, base curve, and thickness must be selected properly.
The document discusses strategies for improving rigid gas permeable (RGP) lens fitting practices. It notes declining RGP prescription rates and argues they remain a good option for many patients. It provides tips for practitioners, including improving RGP knowledge, using correct terminology with patients, starting difficult cases with RGPs, using anesthetic at fittings, ensuring proper edge shape and fit, charging appropriate fees, and not prejudging patients' ability to adapt to RGPs. The overall aim is to remind practitioners why RGPs are valuable and give ways to improve RGP prescription rates.
Contact lens fitting in keratoconus copykamal thakur
This document discusses keratoconus and contact lens fitting options for keratoconus patients. It begins by describing the different types and stages of keratoconus cones. It then discusses the various contact lens options including soft lenses, rigid gas permeable lenses, and scleral lenses. For rigid gas permeable lenses, it explains the different fitting philosophies of apical bearing, apical clearance, and three point touch. Specific lens designs like Rose K2 and scleral lenses are also summarized. Key factors for determining the appropriate contact lens are also listed.
1) A 58-year-old male office worker with keratoconus presented with irritation and dryness when wearing RGP lenses. He had a history of extended computer use in an air-conditioned environment.
2) Examination found punctate staining, neovascularization, nasal dellen, and hyperemia in both eyes. Corneal topography showed increased steepening. Fitting a new scleral lens provided better cone clearance and movement.
3) The patient continued having discomfort from dryness likely caused by his medications, work environment, mild MGD, and tight-fitting lenses. Scleral lenses or modifying the RGP lens parameters were recommended to improve comfort.
This document provides an overview of orthokeratology (orthokeratology), which aims to temporarily reshape the cornea through the overnight use of specialized contact lenses to reduce or eliminate the need for refractive correction. It discusses the history of orthokeratology from its origins in the 1960s using conventional geometry lenses to more modern techniques employing reverse geometry lenses made of high Dk materials. The mechanisms by which orthokeratology reshapes the cornea, patient selection criteria, potential indications and contraindications are described. Advantages include reversibility and potentially slowing myopia progression in children, while disadvantages include its non-permanence and risk of non-compliance.
This document discusses the use of bandage contact lenses after refractive surgery procedures like LASIK and PRK. It describes how bandage contact lenses can help reduce pain, promote healing of the epithelium, and prevent complications like striae or epithelial in-growth after surgery. Different types of bandage contact lens materials are reviewed, including hydrogels, silicone hydrogels, collagen shields, and scleral lenses. Factors like oxygen transmissibility, diameter, and disposable versus reusable lenses are discussed when selecting a bandage contact lens. Potential complications are also mentioned.
The document discusses rigid gas permeable contact lenses, including their benefits, applications, fitting process, and lens design considerations. Some key points covered include:
1. RGP lenses can automatically correct astigmatism, provide good vision and eye health benefits like increased oxygen transmission.
2. The fitting process involves evaluating the lens-cornea relationship using fluorescein dye to identify any bearing, clearance or sealing issues.
3. Important lens design factors are the overall diameter, optical zone size, base curve, thickness, and peripheral curve to achieve a proper alignment fit.
It contains Examination Protocol for Contact Lenses along with information about pre-requisites for fitting a Contact Lens. A helpful guide for all Students, Eye Care Practitioners (Optometrist, Ophthalmologist).
This document discusses various topics related to contact lenses, including:
1. Soft contact lens materials have evolved from HEMA to silicone hydrogels with higher oxygen permeability. The major manufacturers and their market shares are also mentioned.
2. Contact lens optics differ from spectacles in that there is no vertex distance. Accommodative demand and convergence demand are affected differently in contact lenses versus glasses.
3. Rigid gas permeable contact lenses utilize a tear lens between the contact lens and cornea. Parameters like base curve, power, and diameter can be independently adjusted for fitting. Complications like giant papillary conjunctivitis are also discussed.
4. Specialty contact lenses are mentioned for conditions
Scleral contact lenses , types, uses in various ocular conditions.
An in-depth and unbiased details of these lenses as a therapeutic and also as a drug - delivery system in modern ophthalmology.
A must read for all Ophthalmologists and Optometrists.
A glimpse through scleral contact lenses (PROSE)GREESHMA G
This document provides an overview of scleral contact lenses. It discusses what scleral lenses are, their evolution and uses, indications for fitting, anatomy considerations, fitting principles, and care and maintenance. Scleral lenses are large diameter gas permeable lenses that completely cover the cornea and rest on the sclera. They are used for conditions like corneal ectasia, scars, and degenerations to create a liquid bandage over the ocular surface and mask irregular astigmatism. Fitting involves assessing total diameter, clearance, landing zone alignment, and vault to provide a fluid reservoir and stabilize the lens.
Contact lenses were first used in 1880 and were made of glass, but modern contact lenses are made of soft hydrogel or rigid gas-permeable materials. Contact lenses have several optical advantages over glasses such as a larger field of vision, smaller changes in image size with different viewing angles, and less induced astigmatism and prism. The tear layer between a contact lens and the cornea acts as an optical lens (tear lens) that partially corrects astigmatism and influences the final refractive power. Characteristics of different types of contact lenses like soft, rigid gas-permeable and scleral lenses are described for correcting various refractive errors and irregular corneas.
This document outlines the protocol for prescribing contact lenses which involves several steps: patient screening to determine suitability, preliminary examinations and measurements, trial lens fitting to determine the final lens specifications, dispensing the lenses with instructions, and follow-up after-care visits. The trial fitting process aims to select trial lenses that closely match the final prescription parameters and involves assessing the fit and vision until a satisfactory fit is achieved. Desired characteristics of a good contact lens fit include centration, adequate movement, complete corneal coverage, comfort, and good stable vision.
Therapeutic contact lenses are used for therapeutic, diagnostic and cosmetic purposes to treat various ocular surface diseases and conditions. They provide mechanical protection and support to the cornea, maintain corneal epithelial hydration, and can be used to deliver medications to the eye. The type of therapeutic contact lens chosen depends on the specific condition being treated and should aim to maximize oxygen to the cornea unless the eye has no vision. Common complications include ocular redness, minor corneal edema and lens deposits which require regular follow up visits.
This document discusses various options for correcting presbyopia using contact lenses, including monovision, bifocal contact lenses, and multifocal contact lens designs. It provides details on patient selection criteria and explains how different lens designs work, such as simultaneous vision designs that provide distance and near focus simultaneously, and alternating vision designs that translate on the eye to move the add power in and out of the line of sight. Fitting procedures and important considerations for adjustments are also summarized.
This document outlines the project management plan for designing and constructing a modular/residential construction project. It provides details on the project introduction, company profile, site analysis, client requirements, design approach, project management, and conclusions. Key aspects of the project management plan include defining success criteria based on quality, time, and cost objectives. It also discusses risk management and includes a work breakdown structure and Gantt chart to outline the project schedule and tasks. The document aims to provide a comprehensive plan for delivering the project on time and on budget while meeting the client's requirements.
This lab report details an experiment to study the efficient removal of turbidity, color, aluminum, and total suspended solids from river water by varying coagulant dosage, pH, settling time, and stirring speed of a flocculator. An optimum dosage of 0.1mL of polyaluminum chloride was selected with an optimum pH of 7.12, settling time of 1.5 hours, and stirring speed of 250 RPM. The experiment used a Lovibond flocculator and HACH spectrophotometer and colorimeter to test the water quality parameters. Experimental results for pH and coagulant dosage did not fully agree with literature values. Results for stirring speed and settling time agreed with theories from the literature review. Errors
The document summarizes key aspects of contact lens fitting and evaluation. It discusses the anatomy relevant to contact lenses including the tear film and cornea. It then covers common contact lens materials and parameters like oxygen permeability. The document outlines a typical contact lens examination including case history, fitting evaluation, and patient education on proper lens care.
This document provides information about contact lenses, including their specifications, types, uses, and complications. It defines a contact lens as an artificial device that substitutes for the front surface of the cornea to correct refractive errors and corneal irregularities. The main types discussed are hard, rigid gas permeable, and soft lenses. Uses include optical correction as well as therapeutic, preventative, diagnostic, operative, cosmetic, and occupational indications. Complications that can occur involve the eyelids, conjunctiva, and cornea. Contraindications for contact lens use include certain eye diseases and conditions.
This document discusses therapeutic contact lenses (TCLs). It defines TCLs as lenses fitted to maintain or restore ocular tissues. The main aims of TCLs are relief of pain, promotion of healing, mechanical protection, maintenance of hydration, and drug delivery. The document describes various TCL types and their applications for conditions like corneal ulcers, dry eye, trauma, surgery recovery, and more. Complications are also addressed. In summary, it provides an overview of TCLs, including their definition, aims, types, fitting considerations, and clinical applications.
This document discusses paediatric contact lens fitting, including indications for use such as aphakia, pseudophakia, and refractive errors. It covers lens selection considerations like silicone hydrogel and silicone elastomer soft lenses as well as rigid lenses. Examination techniques are outlined, focusing on special approaches needed for babies and young children. Factors specific to fitting soft lenses, silicone rubber lenses, and rigid lenses in paediatric patients are also described.
This document provides an overview of contact lenses, including their history, uses, types, fitting parameters, and indications/contraindications. Some key points:
- The first contact lenses were developed in the late 1800s but were uncomfortable scleral lenses. Modern soft and rigid gas permeable lenses emerged later.
- Contact lenses are used for vision correction, therapy, prevention of eye issues, diagnosis, surgery assistance, cosmetic purposes, and occupations like sports or acting.
- Lens types include soft hydrogel lenses, silicone hydrogel lenses, rigid gas permeable lenses, and the now obsolete hard PMMA lenses. Parameters like material, diameter, base curve, and thickness must be selected properly.
The document discusses strategies for improving rigid gas permeable (RGP) lens fitting practices. It notes declining RGP prescription rates and argues they remain a good option for many patients. It provides tips for practitioners, including improving RGP knowledge, using correct terminology with patients, starting difficult cases with RGPs, using anesthetic at fittings, ensuring proper edge shape and fit, charging appropriate fees, and not prejudging patients' ability to adapt to RGPs. The overall aim is to remind practitioners why RGPs are valuable and give ways to improve RGP prescription rates.
Contact lens fitting in keratoconus copykamal thakur
This document discusses keratoconus and contact lens fitting options for keratoconus patients. It begins by describing the different types and stages of keratoconus cones. It then discusses the various contact lens options including soft lenses, rigid gas permeable lenses, and scleral lenses. For rigid gas permeable lenses, it explains the different fitting philosophies of apical bearing, apical clearance, and three point touch. Specific lens designs like Rose K2 and scleral lenses are also summarized. Key factors for determining the appropriate contact lens are also listed.
1) A 58-year-old male office worker with keratoconus presented with irritation and dryness when wearing RGP lenses. He had a history of extended computer use in an air-conditioned environment.
2) Examination found punctate staining, neovascularization, nasal dellen, and hyperemia in both eyes. Corneal topography showed increased steepening. Fitting a new scleral lens provided better cone clearance and movement.
3) The patient continued having discomfort from dryness likely caused by his medications, work environment, mild MGD, and tight-fitting lenses. Scleral lenses or modifying the RGP lens parameters were recommended to improve comfort.
This document provides an overview of orthokeratology (orthokeratology), which aims to temporarily reshape the cornea through the overnight use of specialized contact lenses to reduce or eliminate the need for refractive correction. It discusses the history of orthokeratology from its origins in the 1960s using conventional geometry lenses to more modern techniques employing reverse geometry lenses made of high Dk materials. The mechanisms by which orthokeratology reshapes the cornea, patient selection criteria, potential indications and contraindications are described. Advantages include reversibility and potentially slowing myopia progression in children, while disadvantages include its non-permanence and risk of non-compliance.
This document discusses the use of bandage contact lenses after refractive surgery procedures like LASIK and PRK. It describes how bandage contact lenses can help reduce pain, promote healing of the epithelium, and prevent complications like striae or epithelial in-growth after surgery. Different types of bandage contact lens materials are reviewed, including hydrogels, silicone hydrogels, collagen shields, and scleral lenses. Factors like oxygen transmissibility, diameter, and disposable versus reusable lenses are discussed when selecting a bandage contact lens. Potential complications are also mentioned.
The document discusses rigid gas permeable contact lenses, including their benefits, applications, fitting process, and lens design considerations. Some key points covered include:
1. RGP lenses can automatically correct astigmatism, provide good vision and eye health benefits like increased oxygen transmission.
2. The fitting process involves evaluating the lens-cornea relationship using fluorescein dye to identify any bearing, clearance or sealing issues.
3. Important lens design factors are the overall diameter, optical zone size, base curve, thickness, and peripheral curve to achieve a proper alignment fit.
It contains Examination Protocol for Contact Lenses along with information about pre-requisites for fitting a Contact Lens. A helpful guide for all Students, Eye Care Practitioners (Optometrist, Ophthalmologist).
This document discusses various topics related to contact lenses, including:
1. Soft contact lens materials have evolved from HEMA to silicone hydrogels with higher oxygen permeability. The major manufacturers and their market shares are also mentioned.
2. Contact lens optics differ from spectacles in that there is no vertex distance. Accommodative demand and convergence demand are affected differently in contact lenses versus glasses.
3. Rigid gas permeable contact lenses utilize a tear lens between the contact lens and cornea. Parameters like base curve, power, and diameter can be independently adjusted for fitting. Complications like giant papillary conjunctivitis are also discussed.
4. Specialty contact lenses are mentioned for conditions
Scleral contact lenses , types, uses in various ocular conditions.
An in-depth and unbiased details of these lenses as a therapeutic and also as a drug - delivery system in modern ophthalmology.
A must read for all Ophthalmologists and Optometrists.
A glimpse through scleral contact lenses (PROSE)GREESHMA G
This document provides an overview of scleral contact lenses. It discusses what scleral lenses are, their evolution and uses, indications for fitting, anatomy considerations, fitting principles, and care and maintenance. Scleral lenses are large diameter gas permeable lenses that completely cover the cornea and rest on the sclera. They are used for conditions like corneal ectasia, scars, and degenerations to create a liquid bandage over the ocular surface and mask irregular astigmatism. Fitting involves assessing total diameter, clearance, landing zone alignment, and vault to provide a fluid reservoir and stabilize the lens.
Contact lenses were first used in 1880 and were made of glass, but modern contact lenses are made of soft hydrogel or rigid gas-permeable materials. Contact lenses have several optical advantages over glasses such as a larger field of vision, smaller changes in image size with different viewing angles, and less induced astigmatism and prism. The tear layer between a contact lens and the cornea acts as an optical lens (tear lens) that partially corrects astigmatism and influences the final refractive power. Characteristics of different types of contact lenses like soft, rigid gas-permeable and scleral lenses are described for correcting various refractive errors and irregular corneas.
This document outlines the protocol for prescribing contact lenses which involves several steps: patient screening to determine suitability, preliminary examinations and measurements, trial lens fitting to determine the final lens specifications, dispensing the lenses with instructions, and follow-up after-care visits. The trial fitting process aims to select trial lenses that closely match the final prescription parameters and involves assessing the fit and vision until a satisfactory fit is achieved. Desired characteristics of a good contact lens fit include centration, adequate movement, complete corneal coverage, comfort, and good stable vision.
Therapeutic contact lenses are used for therapeutic, diagnostic and cosmetic purposes to treat various ocular surface diseases and conditions. They provide mechanical protection and support to the cornea, maintain corneal epithelial hydration, and can be used to deliver medications to the eye. The type of therapeutic contact lens chosen depends on the specific condition being treated and should aim to maximize oxygen to the cornea unless the eye has no vision. Common complications include ocular redness, minor corneal edema and lens deposits which require regular follow up visits.
This document discusses various options for correcting presbyopia using contact lenses, including monovision, bifocal contact lenses, and multifocal contact lens designs. It provides details on patient selection criteria and explains how different lens designs work, such as simultaneous vision designs that provide distance and near focus simultaneously, and alternating vision designs that translate on the eye to move the add power in and out of the line of sight. Fitting procedures and important considerations for adjustments are also summarized.
This document outlines the project management plan for designing and constructing a modular/residential construction project. It provides details on the project introduction, company profile, site analysis, client requirements, design approach, project management, and conclusions. Key aspects of the project management plan include defining success criteria based on quality, time, and cost objectives. It also discusses risk management and includes a work breakdown structure and Gantt chart to outline the project schedule and tasks. The document aims to provide a comprehensive plan for delivering the project on time and on budget while meeting the client's requirements.
This lab report details an experiment to study the efficient removal of turbidity, color, aluminum, and total suspended solids from river water by varying coagulant dosage, pH, settling time, and stirring speed of a flocculator. An optimum dosage of 0.1mL of polyaluminum chloride was selected with an optimum pH of 7.12, settling time of 1.5 hours, and stirring speed of 250 RPM. The experiment used a Lovibond flocculator and HACH spectrophotometer and colorimeter to test the water quality parameters. Experimental results for pH and coagulant dosage did not fully agree with literature values. Results for stirring speed and settling time agreed with theories from the literature review. Errors
The document describes the anatomy and physiology of the human lens and different types of cataracts. It discusses the causes, symptoms, signs, and stages of various cataracts. Treatment options covered include non-surgical management with corrective lenses and surgery using techniques such as intracapsular cataract extraction, extracapsular cataract extraction, small incision cataract surgery, and phacoemulsification. Preplacement testing and postoperative care are also outlined.
The document discusses bifocal lenses, including their history and types. It describes the key components of bifocal lenses: the distance and near portions, and the four basic construction types - fused, solid, cemented, and split bifocals. It provides details on specific bifocal styles like round segment, D segment, and E-style bifocals. The document also covers factors to consider when fitting bifocals, including segment inset, width, and height.
There are several important factors to consider when dispensing bifocal lenses. The optic axis should pass through the center of rotation of the eye. The segment optical centers should be decentered inwards from the distance fitting point. The frame size, shape, and lens material as well as the distance and near prescription powers must be considered. When ordering bifocal lenses, the lab order needs to specify the distance and near powers, type of bifocal, segment size and position, frame details, and lens material.
The document discusses refractive surgeries and provides details on LASIK (Laser-Assisted In Situ Keratomileusis) specifically. It summarizes that LASIK combines lamellar corneal surgery using a microkeratome to create a corneal flap with excimer laser ablation of corneal stroma beneath the flap. The procedure involves creating a corneal flap using a microkeratome, ablating the stroma with an excimer laser according to a calculated profile, and repositioning the flap. Complications are minimized as the flap protects underlying tissues from the laser.
Multi focal lens design, history and optical principlesGauriSShrestha
Multi-focal lens designs provide both distance and near vision correction. The total power is the distance power plus the reading addition power. Early bifocal designs like Franklin's bifocal had separate distance and near lenses but dividing lines were annoying. Later solid bifocals had an upper flatter curve to make the reading segment less conspicuous. Cemented Kryptok bifocals used a higher index wafer for an optically satisfactory result. Modern designs aim to minimize optical issues like prismatic effects, chromatic aberration, and shifting optical centers between viewing distances.
This document discusses LASIK complications and their management. It describes potential intraoperative complications such as incomplete cuts, thin cuts, and free caps. Early postoperative complications include flap-related issues like displacement, wrinkling, and striations. Late complications include epithelial ingrowth, diffuse lamellar keratitis, microbial keratitis, and corneal ectasia. Refractive complications like irregular astigmatism, undercorrection, overcorrection, regression, and ectasia are also reviewed. Prevention and management strategies are provided for each complication.
The frame holds the lenses and prescription in front of the eyes. It generally consists of a front that contains the lenses and temples that hook over the ears. Frame types include plastic, metal, nylon cord, combination, half-eye, and various mounting styles. Bridges can be plastic or metal in different shapes like saddle or keyhole. Endpieces and temples come in different constructions for comfort and fit.
This document summarizes different types of corneal refractive surgery procedures. It describes the anatomy and physiology of the cornea, including its layers and shape. It then discusses various laser eye surgery procedures like LASIK, PRK, LASEK, Epi-LASIK, and intrastromal corneal ring implants. For each procedure, it provides a brief overview and lists the advantages and disadvantages. The goal of these surgeries is to correct refractive errors like myopia, hyperopia, and astigmatism by reshaping the cornea through ablation or incisions.
Pediatric Ophthalmic dispensing in different visual problemsRaju Kaiti
Pediatric dispensing, introduction, different from adult dispensing, frame selection, lens selection, special case fitting, Do's and Dont's, Measurements, Down's syndrome, albinism, aphakia, strabismus, syndromes
The National Academy of Opticianry is dedicated to educating and training dispensing opticians. It provides various membership benefits, educational materials for certification exams, and seminars to help opticians advance in their careers and stay updated in the field. The Ophthalmic Career Progression Program is a multi-volume program that increases opticians' competency through skills training and examinations. The Academy also works with state licensing boards and industry groups to develop standards and regulations for the profession.
The document provides an introduction to refractive surgery, describing different types of refractive errors and methods used to correct them. It discusses procedures like LASIK, PRK, and lens implants. LASIK involves creating a corneal flap then sculpting the cornea with an excimer laser. PRK removes the outer corneal layer then applies the laser. Lens implants are for higher refractive errors or when other methods don't work. The risks, recovery times, and potential outcomes are outlined for each procedure.
Objective, subjective and cyclopegic refractionGauriSShrestha
This document discusses objective, subjective, and cycloplegic refraction. Objective refraction uses optical principles to obtain a measurement without accommodation. Subjective refraction finds the lenses that place the far point at infinity for best visual acuity. Cycloplegic refraction determines the total refractive error during paralysis of the ciliary muscles by cycloplegic drugs. Cycloplegic refraction is indicated for children, accommodative esotropia, and suspected hyperopia or pseudomyopia. Cyclopentolate is commonly used but the appropriate drug and dosage varies by age. Spectacle prescription from cycloplegic findings is an art considering emmetropization in children.
This document provides information about optometry and the optometric education process. It defines optometry as primary eye care and outlines the roles and responsibilities of optometrists. The document discusses the education path to becoming an optometrist, including undergraduate prerequisites, optometry school curriculum, clinical rotations, residencies, and licensing requirements. It also highlights features of the New England College of Optometry such as their clinical education model, research opportunities, and campus location in Boston.
Genetic disorders are not rare and can be classified as cytogenetic, Mendelian, or multifactorial. Cytogenetic disorders involve changes in chromosome number or structure and examples include Down syndrome, Edwards syndrome, and Patau syndrome. Mendelian disorders can be autosomal dominant, autosomal recessive, or X-linked and examples are neurofibromatosis, cystic fibrosis, and retinitis pigmentosa. Multifactorial disorders are influenced by multiple genetic and environmental factors.
This document discusses success with premium intraocular lenses (IOLs) after cataract surgery. It notes that careful patient selection and managing expectations are important but that the primary determinant of patient satisfaction is achieving the desired refractive outcome, which depends on surgeon performance. The discussion emphasizes minimizing surgeon-induced errors through accurate biometry, proper wound construction based on preoperative astigmatism measurements, and precision in lens placement. Multifocal and toric IOLs are described as options to reduce spectacle dependence, while their benefits and risks are outlined. Overall the document stresses the importance of the surgeon generating an accurate refractive outcome to optimize vision and patient satisfaction after cataract surgery.
A cataract is a cloudy area in the lens of the eye that can cause blurred or dim vision. It is the leading cause of blindness worldwide and a common cause of vision impairment in the United States. Cataracts develop due to aging, sun exposure, smoking, poor nutrition, eye trauma, certain diseases, and some medications. Diagnosis involves an eye exam using a slit lamp microscope. Treatment is typically cataract surgery to remove the cloudy lens and replace it with an artificial intraocular lens. The decision for surgery depends on the degree of vision impairment and its impact on quality of life. Modern cataract surgery is a low risk outpatient procedure with rapid recovery of clear vision.
The document discusses considerations for selecting premium intraocular lenses (IOLs). It emphasizes listening to patients' desires and managing expectations. Various IOL options are suitable for different patients depending on their visual needs, personality, and ocular health factors. Careful preoperative evaluation, surgical technique, and postoperative management can help optimize outcomes and patient satisfaction.
1) Intraocular lenses (IOLs) are artificial lenses implanted during cataract surgery to replace the clouded natural lens and correct vision. 2) IOLs have evolved over generations from rigid PMMA lenses to modern foldable designs made of silicone, acrylic, or hydrogel materials. 3) IOLs can be mono-focal, providing a single vision correction, or multi-focal, attempting to provide both near and distance vision without glasses. Accommodating IOL designs also aim to restore the eye's ability to focus at different distances.
Presbyopia is the loss of accommodation that occurs with aging. It results in a decreased ability to focus on near objects and is caused by lenticular and extralenticular changes within the eye. Symptoms typically begin around age 40 and accommodation is completely lost by ages 50-60, affecting 100% of the population. Treatment options include reading glasses, bifocal and multifocal contact lenses, refractive surgery such as LASIK, and intraocular lens implants. Newer treatments being researched include corneal inlays and injectable accommodating intraocular lenses.
Multifocal IOLs provide both near and distance vision without glasses by utilizing concentric zones of different optical powers (refractive MFIOLs) or diffractive properties to split light between two focal points. While eliminating need for glasses, they can cause visual side effects like glare and reduced contrast sensitivity. Careful patient selection and counseling, accurate biometry and surgical technique are important for successful multifocal IOL implantation outcomes.
Orthokeratology, also known as corneal reshaping therapy, uses specially designed contact lenses to temporarily reshape the cornea and reduce or eliminate refractive errors. It allows patients to have clear unaided vision for most of the day by modifying the corneal curvature through overnight lens wear. Studies have shown orthokeratology can slow the progression of myopia in children by an average of 50%. A trial fitting is performed to assess the fluorescein pattern and ensure proper centration, bearing, and tear reservoir before beginning overnight wear to achieve the desired refractive change. Orthokeratology provides an alternative to glasses or surgery and is reversible.
This journal club discussed a study that evaluated the visual outcomes of binocular implantation of a new extended depth of focus intraocular lens called the Supraphob Infocus IOL. The study aimed to assess the safety and efficacy of this lower cost IOL in patients undergoing cataract surgery compared to the FDA approved TECNIS Symfony IOL. The study found that the Supraphob Infocus IOL provided good visual acuity, contrast sensitivity, and stereoacuity outcomes comparable to the TECNIS Symfony IOL. It also induced less ocular aberrations. Based on its safety, efficacy and lower cost, the study concluded that the Supraphob Infocus IOL can
Update knowledge about Muntifocal IOL made by Asaduzzaman
Working as Associate Optometrist in Ispahani Islamia Eye Institute &Hospita, Dhaka 1215
Email:asad.optom92@yaho. com
Th e use of premium IOLs requires more specifically than standard monofocal IOLs a thorough clinical and para clinical examination using modern equipments.
We will only mention micro-incision premium IOLs that are used
in our daily practice. All information regarding the characteristics of all available and especially multifocal IOLs are available in the SFO 2012 Report on presbyopia
This document discusses different types of multifocal intraocular lenses (IOLs) used in cataract surgery. There are three main types: refractive, diffractive, and a combination. Refractive IOLs use concentric rings of different optical powers while diffractive IOLs use diffraction optics to create two focal points. Combination IOLs can provide the advantages of both refractive and diffractive technologies. The document also covers specific multifocal IOL models and considerations for patient selection.
This document discusses different types of intraocular lenses (IOLs) used in cataract surgery. It covers various factors that influence IOL choice such as material, design, and patient needs. The main materials discussed are polymethylmethacrylate, hydrophobic acrylic, hydrophilic acrylic, and silicone. IOL designs include multifocal, toric, and aspherical lenses. Special considerations are mentioned for choosing IOLs in cases of incomplete capsule support, high myopia, or uveitis. The document provides details on characteristics and indications for different IOL materials and designs.
This document discusses cataracts and presbyopia, as well as treatment options performed by Dr. Helga Fuenfhausen Pizio. A cataract is a clouding of the eye's lens that causes vision problems and is common in older adults. Symptoms include blurry or faded vision. Surgery is the only treatment and involves removing the clouded lens and replacing it with an artificial lens. For presbyopia, which causes near vision issues, multifocal lenses can provide both near and distance vision after cataract surgery without glasses. Dr. Pizio performs cataract surgery using small incisions and ultrasound and was the first in Nevada to implant a new multifocal lens.
Dissatisfied patient after cataract surgery: How to AvoidSeshu Gosala
This document discusses planning considerations for premium cataract surgery using multifocal or toric intraocular lenses (IOLs). It outlines the importance of detailed preoperative evaluation and counseling of patients. Key factors in patient selection include personality, lifestyle needs, and ocular health. The document also discusses technologies like femtosecond lasers and image guidance systems that can improve astigmatism correction and IOL placement for optimal visual outcomes.
Accommodative and multifocal intraocular lensesBijan Farpour
This document discusses accommodative and multifocal intraocular lenses (IOLs) that are surgically implanted to replace the eye's natural lens and help restore vision and the ability to focus at different distances. It provides information on how the eye works, common refractive errors, the IOL procedure, types of IOLs including multifocal and accommodative IOLs, risks and considerations, and whether refractive surgery is right for a given patient.
Richard L. Lindstrom, MD's "Thoughts on Corneal and Lens based Refractive Surgery to Enhance Near Vision in the USA: 2015" presentation from OIS@ASCRS 2015
- A cataract is a clouding of the lens in the eye that can cause vision loss. It is often related to aging but may be caused by other factors like smoking.
- Symptoms include decreased vision, glare from lights, and frequent changes to prescriptions. Cataract surgery is usually done to replace the cloudy lens with an artificial lens implant.
- There are different types of intraocular lenses that provide varying levels of vision correction and independence from glasses after surgery. Conventional lenses correct one distance while newer lenses aim to provide multifocal vision.
Mercurius is named after the roman god mercurius, the god of trade and science. The planet mercurius is named after the same god. Mercurius is sometimes called hydrargyrum, means ‘watery silver’. Its shine and colour are very similar to silver, but mercury is a fluid at room temperatures. The name quick silver is a translation of hydrargyrum, where the word quick describes its tendency to scatter away in all directions.
The droplets have a tendency to conglomerate to one big mass, but on being shaken they fall apart into countless little droplets again. It is used to ignite explosives, like mercury fulminate, the explosive character is one of its general themes.
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5-hydroxytryptamine or 5-HT or Serotonin is a neurotransmitter that serves a range of roles in the human body. It is sometimes referred to as the happy chemical since it promotes overall well-being and happiness.
It is mostly found in the brain, intestines, and blood platelets.
5-HT is utilised to transport messages between nerve cells, is known to be involved in smooth muscle contraction, and adds to overall well-being and pleasure, among other benefits. 5-HT regulates the body's sleep-wake cycles and internal clock by acting as a precursor to melatonin.
It is hypothesised to regulate hunger, emotions, motor, cognitive, and autonomic processes.
- Video recording of this lecture in English language: https://youtu.be/Pt1nA32sdHQ
- Video recording of this lecture in Arabic language: https://youtu.be/uFdc9F0rlP0
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8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
The skin is the largest organ and its health plays a vital role among the other sense organs. The skin concerns like acne breakout, psoriasis, or anything similar along the lines, finding a qualified and experienced dermatologist becomes paramount.
DECLARATION OF HELSINKI - History and principlesanaghabharat01
This SlideShare presentation provides a comprehensive overview of the Declaration of Helsinki, a foundational document outlining ethical guidelines for conducting medical research involving human subjects.
4. During cataract surgery, your eye's natural
lens is removed and replaced with an IOL.
Standard monofocal IOLs probably will give
you great distance vision
Many times… patients require glasses after the procedure
5. Available IOL Technology:
◦ Toric IOLs
◦ Presbyopic IOLs
Multifocal
Accommodating
These options are considered PREMIUM
because they can provide a better visual
outcome after cataract surgery than a
standard IOL.
6. ◦ Staar Toric IOL (Staar Surgical)
Available in two powers
Staar Toric IOL
Silicone Material FDA Approval – 1998
Up to 3.5D.
◦ Acrysof Toric IOL (Alcon)
Corrects 1.5D to 3.0D astigmatism
Acrylic Single Piece Lens Acrysof Toric IOL
Increased Stability FDA Approval – 2005
◦ Acrysof IQ Toric IOL (Alcon)
Corrects 1.5D to 6.0D astigmatism
Enhanced Aspheric optics Acrysof IQ Toric IOL
UV blocker FDA Approval – 2009
7. Powers Range
◦ -1.50D to -6.00D
Effective Power
◦ up to -4.11D
Accurate Measurements
◦ Lenticular / Refractive / Corneal
cylinder measurements
Keratometry
Topography
Toric Calculator
The AcrySof® Toric IOL Calculator is an easy-to-
use, highly accurate tool that helps surgeons to select the
appropriate IOL model and provides recommended axis
placement of the IOL in the capsular bag
8. Stability of the bag is in question
◦ An unstable capsular bag with pseudoexfoliation.
◦ In these patients, the lens may rotate once
implanted, altering the patient’s vision.
9. Corneal topography shows anything other than the "bow-tie"
pattern of regular astigmatism
◦ A toric IOL will probably not treat astigmatism successfully if the cornea is
irregular
11. Since the mid 1980s, dozens
of FDA trials have examined
the efficacy and safety of
presbyopia-correcting IOLs.
Many early lenses
demonstrated only moderate
patient satisfaction.
Today’s advanced and
extensively tested technologies
are yielding outstanding
postoperative outcomes.
12. Multifocal IOLs
Use technology called diffractive and refractive optics.
This design provides both a distance and near focus
at all times. Your brain will learn to automatically
select the focus that is required at that time.
Accommodating IOLs
This design mimics the movement of the natural crystalline
lens of the eye. Accommodating IOLs are able to move
and/or change shape inside the eye to allow focus at
multiple distances.
13. Second-generation, refractive
multifocal lens.
Aspheric transitions between
zones provide intermediate
vision
+3.50D at IOL plane
+2.85D at the spectacle
plane
Previously the ReZoom was
considered the strongest
multifocal IOL for enhancing
intermediate vision, but now
it has competition…
FDA approval in March 2005
14. Uses an aspheric optic
design to offset the
spherical aberration of the
cornea.
+4.00 at the IOL plane
According to FDA
data, the Tecnis Multifocal
IOL provides both good
near and distance vision.1
Study found patients’ reading
speeds to be 175 words per
minute in bright light and
142 words per minute in low FDA approval in January 2009
light.
15. Most frequently implanted
presbyopia-correcting IOL for
cataract patients worldwide
since 2005
Its design is based on the
optical principle of
apodization—a series of
graduated steps that result in
diffraction of light
ReSTOR 4.0
◦ +4.00 Add at the IOL plane
ReSTOR 3.0
◦ +3.00 Add at the IOL plane
◦ +2.50 Add at the spectacle plane
The result is ability to focus on
items at
distance, intermediate, and
near. FDA approval in March 2005
17. First and only FDA-approved
accommodating IOL
Designed to move within the
eye, to provide focusing at
all distances.
Crystalens HD’s haptic acts
as ―hinge‖ that allows the
lens to move forward and
flex secondary to vitreous
pressure during
accommodation.
Aberration Free
18. Multifocal IOLs
• These designs work because the brain learns to select the appropriate zone to
"look" through to provide sight at near, intermediate or far ranges.
• Diffractive multifocal IOLs, are great for distance and near vision, but are not
optimal for intermediate distance and may cause minor amounts of distortion.
• Major drawback is low contrast sensitivity.
Accommodating IOLs
• With one focusing zone it is less likely than multifocal IOLs to produce visual side
effects for distance vision such as night vision problems including glare and halos.
• At long distance, it is possible that vision may be crisper with accommodating IOLs.
• May not provide as much of a range of focus (near to far) as multifocal IOLs, and
this might lead to the need for reading glasses.
20. Getting involved in
cataract procedure
presents a great
opportunity for the
doctor/patient relationship
Layout the options but
make a recommendation
Who knows more about
the refractive status, eye A patient who reads a lot of
health and complete eye paperback novels may be a
better candidate for the
care of the patient than ReSTOR, while a heavy computer
the optometrist? user might be best served with a
Crystalens.
21. Standard vs Premium IOL The final decision should
be made between the
patient and the
optometrist, and then that
decision should be
communicated to the
surgeon.
◦ Obviously this may be altered
by the surgeons
recommendations but having
the patient already informed
about their options is always
welcome.
22. Good candidates are generally
◦ Easy-going
◦ Realistic in their expectations
◦ Willing to accept a few tradeoffs
Patient must be aware of the cost of cataract surgery
involving premium lenses.
◦ While most Medicare and private insurance will cover basic
cataract surgery costs, you still will need to pay out-of-pocket the
extra price of "premium" IOLs that are considered cosmetic and
not medically necessary. These costs can be as high as $2,500 per
eye.
Several factors determine the IOL that best suits each
patient. These include the patient’s
occupation, hobbies, daily activities, pupil size and retinal
health.
23. Clean Ocular Surface
◦ All of these common conditions must be addressed prior to multifocal IOL
implantation to maximize patient outcomes.
Dry eye
Blepharitis
Allergies
Pathology
◦ Anterior segment
Pterygium
Corneal Abnormalities
Chalazion
◦ Posterior segment
Epiretinal membrane
Macular Degeneration
Glaucoma
Etc.
Understanding Astigmatism
◦ Keratometry
◦ Topography
24. Always mention glare and halos.
◦ Remind them of their current cataract
symptoms of glare and halos, and that they
may continue to see halos at night post-
surgically, but to a much lesser extent.
Nothing’s ever going to work as well as
the natural accommodation system
◦ Remind them this is the best available
technology at this time.
They may occasionally need a pair of
glasses from time to time.
◦ Especially when reading for long periods of
time or in dim illumination
25. • The Optometrist should be able to recognize potential problems
and be prepared for the possibility of other necessary surgeries.
• These extra procedures should not be viewed as a complication of
cataract surgery but as part of the process in obtaining good vision.
• An Optometrist who is vigilant before and after surgery plays a
major role in IOL surgery success!
LRI (Limbal Relaxing Incision)
◦ This performed by making a pair of deep incisions at the corneal limbus, anterior to
the vascular arcade. The length and placement of the incision is dependent upon the
axis and amount of astigmatism. LRIs work well if the spherical equivalent is close to
plano, and the astigmatism is under two diopters.
LASIK or PRK
◦ Postoperatively, if the patient has residual myopia, hyperopia or astigmatism—may
be a candidate for a touch-up LASIK or touch-up PRK.
Piggyback IOLs
◦ This procedure can correct small or large spherical refractive errors after cataract
surgery, but they are rarely utilized.
IOL exchange
◦ Replacement of the IOL is always the last resort
26. ◦ AcrySof IQ ReSTOR Multifocal Toric The company has said that it plans to
file a pre-market application with the FDA in early 2012 for possible U.S.
approval.
◦ The At Lisa Toric Multifocal IOL. An aspheric, toric, diffractive bifocal IOL that
corrects combined refractive errors.
◦ Synchrony Dual-Optic Accommodating IOL. This is a dual-optic system.
When the ciliary body is relaxed, the optics remain close together for
distance vision. When the ciliary body contracts, the optics move apart, which
increases lens power and provides optimum near acuity.
◦ Tetraflex Accommodating IOL. Tetraflex (Lenstec, Inc) has two haptics and
moves anteriorly secondary to vitreous pressure. This action, in
turn, enhances near acuity.
◦ The NuLens Accommodating IOL (NuLens Ltd.) Stated as having potentially
up to 10 diopters of accommodation for a wider range of focus, compared to
only about two diopters provided by currently approved IOLs.
◦ FluidVision Accommodating IOL (PowerVision) uses fluid-based mechanics to
change its shape in response to the movement of eye muscles. The lens is in
the early stages of human clinical trials, but so far appears capable of
providing more than 5 diopters of accommodation.
◦ The Light Adjustable Lens. The Light Adjustable Lens is comprised of a
photosensitive silicone material that can be postoperatively reshaped with
ultraviolet light to correct any residual refractive error.
28. Historically, multifocal contact lenses have
been perceived as complex and providing
limited success.
But the truth is, they are relatively easy to
fit, enjoy higher—if not much higher—
success rates compared to 10 to 20 years ago
Multifocal lenses represent the best option
for the majority of presbyopic patients who
are interested in contact lens wear.
32. Diffractive designs
◦ Diffractive lenses utilize concentric phase plates to
diffract light.
◦ This lens design induces significant ghosting of
images.
Due to these limitations, there are no current diffractive multifocal
contact lenses on the market
The Hydron Echelon lens [CooperVision] was discontinued in March 2006
33. Aspheric designs offer a gradual change in
power from the center to the periphery.
◦ Anterior surface
◦ Posterior surface
Aspheric multifocal lenses in general provide
a smooth progressive vision effect that
simulates pre-presbyopic vision function.
34. Anterior Aspheric
◦ Plus power is greatest in the center of the lens progressing
to more minus in the periphery.
For very small pupils, the near power will be emphasized and
distance vision will be compromised.
For very large pupils the near vision will be compromised
Posterior Aspheric
◦ Plus power increases toward the periphery.
For very small pupils, the distance power will be emphasized and
near vision will be compromised.
For very large pupil the distance vision will be compromised
35. This design uses a distance or near optical
zone, which makes pupil size and lens
centration critical for the fit.
◦ Distance-centered
◦ Near-centered
◦ Pupil-intelligent
◦ Aspheric-blended varieties.
This design incorporates distinct annular
zones of power to create their multifocal
effect.
37. Alternating or translating designs have the
advantage of distinct and separate areas
dedicated to vision for distance and for near.
The positioning of the line of sight in
alternating multifocals is entirely dependent
on lens positioning in primary gaze and
translation upon inferior gaze.
The distance and near portions of the lens are
never used simultaneously.
Lens stability controlled by either prism or
truncation.
38. With appropriate base curve selection and
proper lid interaction, the lens will translate
up during downward gaze allowing the
patient to utilize the add in the lens
During primary gaze, the segment is
positioned below the pupil allowing the
patient to utilize only the distance portion
of the lens
39.
40. Most GP multifocal lenses utilize alternating
vision effects to some degree because they
move with the blink and will translate to
varying degrees with inferior gaze.
With isolated exceptions, soft and hybrid
multifocal lens designs are simultaneous
designs because they do not move
significantly with the blink or translate with
inferior gaze.
41. Advantages
◦ Offers intermediate vision
◦ Near can be viewed without using downward gaze
◦ Lens design is thinner and more comfortable to wear
◦ Stereopsis is maintained
◦ Lid positioning is not as important to the success
Disadvantages
◦ Pupil size is a consideration to success
◦ Patients may experience flare and ghosting
◦ May experience reduced night vision
42. Advantages
◦ Gives sharp distance and near vision
◦ Not as dependent on pupil size
◦ Interferes less with night vision
Cons
◦ Less comfortable due to edge thickness
◦ No intermediate vision
◦ Lid tension and position must be
appropriate for design to work
◦ Can only view near on downward gaze
43. The soft multifocal contact lens market is
dominated by the silicone hydrogel designs
from the major manufacturers.
44. Back of your mind Baseball Player
◦ Distance Lawyer
#1 Mechanic
◦ Intermediate
Drive at night
◦ Near Waiter in restaurant
Security Guard
#2 ◦ High Light (small pupil) Photographer
◦ Low Light (large pupil)
Anterior Aspheric Posterior Aspheric Distance Center Concentric Near Center Concentric Alternating
45. The key to fitting success is to appropriately
match an individual patient's vision demands
and with the proper design.
Success is based on the realization that no
one lens design is superior to another.
47. If a patient is not motivated psychologically…
it is going to make your job that much harder.
Appearance - Patients wear contact
lenses because they want to lose the
glasses.
◦ Multifocal lenses psychologically hide this
aging process.
Convenience -Presbyopia is especially
frustrating when its new. These
patients never had a problem to read
a menu, sign a check, etc.
48. What are the patients' vision expectations?
How and when do they want to wear
multifocal lenses?
Does the patient want to wear contact lenses
full time, daily yet limited hours, or
occasionally?
What specific activities are most important?
Consider the vision demands of those
responses and how the various designs
might perform under those circumstances.
49. Discuss
◦ Comfort
◦ Cost
◦ Acceptance
If you are able to discover
that a given patient is not
able to afford multifocal
lenses, or that he would not
accept the vision outcomes
available, or would not be
able to tolerate physical lens
adaptation, then you could
avoid wasting his time and
yours.
50. There are certain anatomical factors that will
help you choose an appropriate lens design
◦ Corneal Abnormalities
◦ Tear film quality and quantity.
◦ Lid margins
Anterior and/or posterior blepharitis.
◦ Allergic conditions
Also be aware of all prescribed that can affect
the corneal surface.
Pupil size is important, especially in
extremes.