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Initial summary: This patient was a 22-year single vision rigid gas permeable lens wearer who presented with reduced wearing time, near and distance problems and lens awareness. History: 41-year-old bank executive, mother of two without any allergies and is on no medications. Family history unremarkable. Anterior segment evaluation: Contact lenses grade 2+ scratches and central SPK O.U. without vascular changes and no 3:9 staining. Trace hyperemia. Central positioned lens design with little movement. Presenting rigid gas permeable design: 9.5 polycon design Manual keratometry:
Refraction: Pupil size 4.5 Mesopic 5.0 Scotopic Patient required improved intermediate and near vision to perform work at the bank, especially with computers. Patient required improve intermediate and near vision to help the kids with homework. Distance vision seemed to diminish over the last six months. Patient wants to know, "Why all of a sudden have my vision and comfort changed?" What do I tell her? What is the etiology of SPK without three-nine staining and with minimal hyperemia? What fitting philosophy would you use (soft, rigid)? What lens design would you use? (Single vision contacts with over refraction, Push plus, Monovision, Reading glasses, Bifocals) Patient was seen by my associate and his initial lens design ordered and dispensed: First Follow-up Visit Patient requested I take a look at the case due to continued distant and near visual problems and comfort issues not resolved. Fluorescein: Typical spherical lens on a with-the-rule toric cornea. Dumb-bell pattern. How would you explain to the patient the visual and comfort problems she is experiencing after 22 years of wearing gas permeable rigid lenses? What modifications to the lens design would you employ next? Lens design: Toric Base Eccentric Front Aspheric Bifocal Fluorescein pattern of a toric base curve on an astigmatic cornea looked spherical. Discussion: Patients with myopia require a bifocal add earlier and more add power in contact lens Rx compared to their spectacles. Hyperopic patients require a bifocal add earlier and increased add power in their spectacle Rx compared to their contact lenses. Utilizing the front and back surfaces of a contact lens for power increases your options for success with bifocals. The back surface of the contact lens is reserved for improved corneal/lens relationship.
A retired gentleman presented himself with complaints of inadequate near vision. He is tired of carrying his glasses around with him in order to perform near point tasks. He has never worn contact lenses before, and he has reading-only glasses. His wife is a GP lens wearer of 20 years. He would like to wear soft bifocal contact lenses. Systemic medications include triamterene, terazosin, altace, allopurinol, potassium. Family history remarkable for glaucoma (father) for this 63-year-old male. Patient needs improved near vision for computer and newspaper. Refraction: Manual keratometry:
Pupil size 4.5 Mesopic 6.0 Scotopic Patient preference is to wear soft bifocal disposable lenses. How would you communicate to the patient your fitting options? What lens design would you use? (Single vision contacts with over refraction, Push plus, Monovision, Reading glasses, Bifocal) Dispensed: Visual acuity: First Follow-up One Week Appointment Patient not comfortable with distance or near vision. Patient enjoys not having to wear glasses. Would like distant vision a little better. Willing to compromise vision in order not to wear glasses. Patient had no problems with lens comfort, lens cleaning/disinfection and application/removal. Dispense second soft lens design and reappoint for one week follow-up visit: Visual acuity: Patient still not happy with visual outcome. Right eye sees better at distance and left eye sees better at near. Nighttime glare with halos around lights. Patient requires reading glasses for reading small print. Happy with intermediate and distant vision. How would you communicate to this patient his next fitting options? Does he have to compromise his vision or comfort in order to get a complete solution? What lens design would you use? (Single vision contacts with over refraction, Push plus, Monovision, Reading glasses, Bifocal) Dispense Tangent Streak Alternating Bifocal: One Week Follow-up Visual acuity: Patient had no problems with lens comfort, lens cleaning/disinfection and application/removal. Patient enjoys not having to wear glasses with adequate distant and near vision. Discussion: Rigid gas permeable alternating designs work best on patients who have near plano prescriptions. Lower lid positions below the limbus are not always contraindications for translating rigid gas permeable lens designs. Lenses can always be designed larger in order to produce proper lens translation. Loose flabby lids present more of a contraindication.
Summary: LS, a 61-year-old woman, has worn rigid contact lenses for 38 years. She presented for her most recent examination with a complaint of difficulty with near vision. History: A very active grandmother has unremarkable ocular and general health, however did indicate that she is on hormone replacement therapy. Her daily activities include computer and desk work related to bookkeeping three hours a day. Her hobbies include tennis and reading. Anterior segment evaluation: Lids, lashes and corneas were clear. There were not any significant signs of dry eye or tear film deficiencies. Presenting gas permeable lens design: She was currently wearing an aspheric multifocal with an
effective add of +1.75 D. The lens centered well and gave adequate distance vision. Keratometry: Corneal Topography:
Refraction: Ocular measurements: Considerations for lens designs: LS needed an improved range of near vision to allow her to read small print. She also needed to have the intermediate range of vision to meet her computer vision requirements. Patient concerns: She wants to be able to read small print without using supplemental reading spectacles. She has a real concern for the possibility of "Not being able to continue wearing contact lenses." What are the advantages to staying with aspheric design multifocal gas perm contact lenses? Would there be any advantages to switching to disposable lenses ("S" lenses) or to a translating (alternating) design? Treatment: An evaluation of various lens designs was considered. I chose to stay with the aspheric design because she was able to get good distance vision and also achieved acceptable midrange vision. I refit the patient in the Essentials III CSA design that utilizes an expanded reading power by applying an additional +0.50 add on the front surface and as a result was able to get an effective +2.25 reading add power. Lens design: Spherical base curve with aspheric peripheral curves with an additional add effect on
the front surface. In this design it is necessary to steepen the base curve to allow for the flatter aspheric peripheral curve system. Follow-up visits: There was some difficulty with stability with distance, requiring the patient to turn her head at distance to get good distance vision. Fluorescein pattern/riding position evaluation confirmed that there was excessive lens movement causing intermittent blurred vision at distance. It was determined that there was too much edge lift and a change in the lens edge design to lower the edge lift. New lenses were dispensed with the new edge design and improved lens position was confirmed at a subsequent follow-up visit. Discussion: This case demonstrates that an aspheric multifocal with a high add can be effective when the lens centers well and does not cause corneal distortion. Summary: LM, a 54-year-old female, has worn contact lenses since age 14. She is having difficulties with small print and with distance vision when driving, especially at night. History: LM is a training specialist for a large utility company. Her vision demands require her to give PowerPoint presentations and also do up to six hours a day of computer use. Her ocular health history is unremarkable except for minimal side effects to seasonal pollens. Her general health is good; however, she does use hormone replacement therapy. Her hobbies include walking and reading. Anterior segment evaluation: Lids, lashes and corneas were clear. There were not any signs of dry eye or tear film deficiencies. The current gas permeable contact lenses are three+ years old and appear to have some deposits and scratches. Presenting gas permeable contact lens design: LM was wearing single vision gas permeable contact lenses in
monovision design. Her dominant right eye was designated as the distance eye, and her left eye was the near eye. She was
wearing a thin lens design in Boston ES material. Her near eye had an effective +1.75 add. Keratometry: Topography:
Refraction: Ocular measurements: Consideration for lens design: LM needed more effective reading add in addition to an effective mid range for computer. Her symptoms at distance can be related to the blurred vision in the non-dominant eye, especially when driving at night. Patient concerns: LM is unhappy with the limited range of vision at near and the associated discomfort associated with sustained near point tasks. Considerations: Would she be happy wearing spectacles to correct the left eye for driving at night? What about a pair of single vision specs for near that would make her binocular? Would she be successful switching to aspheric multifocal contact lenses or some type of translating contact lens that provides a midrange for computer use? Treatment: A contact lens work-up utilizing various lens designs was performed. I chose an annular translating design with defined distance optics, an effective midrange and a full +2.00 add for near. After considering an aspheric design and modified monovision approach, I utilized a Mandell Seamless Multifocal in Boston XO material. She was able to achieve binocular distance vision and an improved ability to read small text at reading distance. Lens design: Follow-up visits: The lenses centered well. The distance central zone (seg) was centered within the pupil in the primary gaze position, and the lens translated upward slightly upon downward gaze position, allowing for adequate near vision. Visual acuities are 20/20-, OD, OS and OU @ distance and 20/20 at near, OU. The patient adapted well to binocular distance vision. The lens translates adequately at near, giving good near vision. Learning to position head for midrange vision was effectively managed. Discussion: This case demonstrates the advantages of multifocal contact lenses in occupational settings, as well as the importance of selecting the suitable candidate. It is extremely important to recognize that happy (asymptomatic) monovision wearers do not make suitable multifocal contact lens patients! It is also important to utilize a higher dk lens material when going to a design that requires a thicker lens. | |||||||||||||||
