Takayuki Momose, Nobuko Ito, Atsushi Kanai, Yasuo Watanabe, Minoru Shibata
Noemi Lois, Jorge L. Dias, Elisabeth J. Cohen
Frank A. Bucci, Jr., Patti J. Myers, Ruth E. Evans, Jay B. Tanner, Kurt J. Moody, Marta O. Lopatynsky
Lakshmi Ramachandran, Devipriya Janakiraman, Savitri Sharma, Gullapalli N. Rao
Patrick McConville, James M. Pope, Joseph W. Huff
Lyndon Jones, Kathryn Evans, Reyhaneh Sariri, Valerie Franklin, Brian Tighe
María Josefa Valasco Cabrera, José García Sánchez, Francisco Javier Bermúdez Rodríguez
Li Lim, Tze Pin Ng, Donald Tiang Hwee Tan
Kiyoshi Watanabe, Hikaru Hamano
H. Jay Bruninga, Robert W. Enzenauer, Randall S. Robbs
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Copyright 1997 Contact Lens Association
of Ophthalmologists, Inc.
Takayuki Momose, MD; Nobuko Ito, MD; Atsushi Kanai, MD; Yasuo Watanabe, MD; Minoru Shibata, MD
Purpose: We evaluated the adsorption of levocabastine (LEV) eye drops onto soft contact lenses in rabbit eyes to confirm the safety of this antihistaminic and antiallergic agent.
Methods: Low- and high- water-content soft contact lenses were placed on the eyes of three rabbits for each type of soft contact lens (total: six rabbits) for 8 hours daily. LEV eye drops and physiological saline solution (used as a control) were instilled into the experimental eye and the fellow eye at a dosage of 0.1 mL per eye, at 1 hour intervals, eight times daily, for 6 consecutive days. Severity of possible eye injury was evaluated before soft contact lens insertion and after removal.
Results: After completion of the study, the amounts of LEV and the preservative benzalkonium chloride (BAK) adsorbed onto the soft contact lenses were assayed using high-performance liquid chromatography. There were no significant differences between the experimental solution and the control solution using Draize's method scores or slit lamp evaluation.
Conclusion: LEV and BAK accumulated only slightly in the soft contact lenses, leading us to conclude that LEV eye drops could be used safely by soft contact lens wearers for about 1 week.
Noemi Lois, MD; Jorge L. Dias, MD; Elisabeth J. Cohen, MD
Purpose: The purpose of this study was to describe the outcome of patients with filtering blebs who were fit with contact lenses.
Methods: We retrospectively studied patients with filtering blebs secondary to glaucoma or cataract surgery who were fit with contact lenses. Eight eyes from seven patients were identified.
Results: Five patients (six eyes) were fit with gas permeable contact lenses and two patients (two eyes) were fit with soft contact lenses. Successful fits were achieved in all patients. No complications were observed after a mean follow-up of 64.6±28.5 months.
Conclusions: No significant complications were recorded in our series of patients with filtering blebs who were fit with contact lenses. We think that when indications for fitting contact lenses are justified, patients with filtering blebs are acceptable candidates for contact lens use. However, adequate selection of cases, careful contact lens fitting, patient education, and close follow-up are necessary.
Frank A. Bucci, Jr., MD; Patti J. Myers, COT; Ruth E. Evans, COT; Jay B. Tanner, OD; Kurt J. Moody, OD; Marta O. Lopatynsky, MD
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Purpose: We characterized the clinical performance of the 1-Day Acuvue contact lens by direct comparison with four frequently prescribed daily wear lenses.
Methods: Forty-eight patients participated in four prospective, randomized masked clinical trials using the 1-Day Acuvue in one eye and the Medalist, Surevue, Acuvue (regular), and Biomedics 55 lenses in the other eye. Each trial lasted 2 weeks. Thirteen symptom variables and overall lens preference were evaluated using a patient preference questionnaire and a symptom-ranking questionnaire. Overnight corneal swell studies were also performed.
Results: In the non-allergic (58.4%) subgroup, the overall lens preference variable revealed a significant preference for the Medalist (P =.004), Surevue (P <.001), and Biomedics 55 (P <.001) lenses. In contrast, in the allergic (41.6%) subgroup, the overall lens preferences for the Medalist, Surevue, and Biomedics 55 lenses were completely absent. Multivariate regression analysis in the non-allergic subgroup revealed that lens comfort (.58, P <.001), lens handling upon insertion (.41, P <.001), and quality of vision (.35, P <.001) were significant variables contributing to patient responses regarding overall lens preference. However, in the allergic subgroup, only the lens comfort (.92, P <.001) variable is significant and appears to dominate the decision making. The overnight corneal swell evaluation revealed no significant differences between the 1-Day Acuvue and the Medalist lens. Patients wearing regular Acuvue had significantly less corneal swelling upon awakening (P =.005) and at 60 minutes after awakening (P =.003).
Conclusions: The Medalist, Surevue, and Biomedics 55 lenses out-performed the 1-Day Acuvue lens in the non-allergic subgroup. In the allergic subgroup, there was no statistically significant difference between the 1-Day Acuvue lens and all other lenses tested.
Lakshmi Ramachandran, B.opt; Devipriya Janakiraman, B.opt; Savitri Sharma, MD; Gullapalli N. Rao, MD
Purpose: This study was undertaken to determine the extent of adhesion of cysts and trophozoites of Acanthamoeba to worn disposable hydrogel lenses and to study the effect of time, lens material, and washing on the adhesion.
Methods: Etafilcon A (58% water content) and Polymacon (38% water content) lenses worn on a 6 night extended wear basis and collected aseptically in PBS pH 7.2, were used for the study. Unworn lenses of the same materials were used as controls. Segments of lenses were incubated in Acanthamoeba suspension (cysts and trophozoites) and examined at 0, 5, and 24 hours, either washed or unwashed, for adherent Acanthamoeba. The amoebae adherent per square mm surface of the lens were enumerated. Levels of adhesion in various groups were compared using Wilcoxon sign rank test.
Results: At 0 hours, unwashed worn Polymacon lenses showed significantly greater adherence than Etafilcon A lenses compared to the controls (P=0.0469). However, there was no difference at 5 and 24 hours exposure time between the lenses. At 24 hours the adhesion of Acanthamoeba was greater for washed worn lenses of both types compared to washed lenses of controls (P=0.002, 0.012).
Conclusions: Amoebae adhered with equal affinity to both types of lenses but adhered with greater affinity to worn lenses than unworn lenses. Adhesion of Acanthamoeba to worn disposable lenses may be a factor in the pathogenesis of Acanthamoeba keratitis in disposable lens wearers.
Patrick McConville, BSc (Hons); James M. Pope, DPhil; Joseph W. Huff, PhD
Purpose: The purpose of this study was to use in vitro dehydration and rehydration data to model the predicted hydration changes that may occur as a soft contact lens loses and gains water on the eye between blinks.
Methods: Using a recent in vitro data set for four lens materials dehydrated and rehydrated in saline, we derived a mathematical model to describe dehydration and rehydration time courses. The model further combined the dehydration and rehydration data iteratively, as a function of blink frequency, and pre-lens break-up time.
Results: The model showed that reduced break-up times or decreased blink frequencies significantly affected dehydration rates and steady state dehydration for lenses of a variety of water contents. However, the model did not agree with the commonly accepted clinical belief that high water content lens materials dehydrate more than low water content materials.
Discussion: The discrepancy of the model with historical observations may be accounted for by one or more of the following factors, which were not accounted for in the present model: 1) temperature dependent dehydration (as a lens is taken from a room temperature vial and warmed when placed on the eye); 2) the colloid osmotic pressure, ionicity, pH, and chemical potential of tears (compared to saline); and 3) dehydration by other non-evaporative mechanisms.
Lyndon Jones, BSc, FCOptom; Kathryn Evans, BSc; Reyhaneh Sariri, MSc, PhD; Valerie Franklin, PhD; Brian Tighe, PhD
Purpose: The purpose of this study was to investigate the degree of protein and lipid deposition that occurs on N-vinyl-2-pyrrolidone (NVP) containing group II (non-ionic, high water content) and NVP containing group IV (ionic, high water content) frequent replacement hydrogel contact lens materials.
Methods: Twenty subjects were fitted with Group II (Vasurfilcon A) and Group IV (Vifilcon A) contact lenses, which were replaced monthly. The lenses were worn as a contralateral pair for 3 consecutive monthly periods. At the end of each monthly period, the lenses were collected for analysis of protein and lipid deposits. Protein deposition (following extraction) was examined by transmission UV and lipoidal deposition was examined using fluorescence spectrophotofluorimetry.
Results: There was a significant difference in the lipid and protein deposition profiles between the two materials. The Group II lens deposited approximately 2x more lipid (38 versus 73 fluorescence units; P<0.0001) and the Group IV lens deposited approximately 17x more protein (488µg versus 28µg; P<0.0001). Whilst the mean results across months were not significantly different for either protein or lipid (P=NS), the results revealed significant inter- and intra-subject variation.
Conclusions: Protein deposition was predominantly controlled by the ionic charge of the lens materials, whereas the lipid deposition was predominantly determined by the NVP content. This study demonstrates that inter-subject variation and material characteristics significantly influence the deposition profile of hydrogel contact lens materials.
María Josefa Velasco Cabrera; José García Sánchez; Francisco Javier Bermúdez Rodríguez
Purpose: The purpose of this study was to examine the concentration of lactoferrin in 126 healthy subjects before being fitted with contact lenses. We obtained repeat measurements 9 months following contact lens fitting in patients who developed giant papillary conjunctivitis and in those who were successful contact lens wearers.
Methods: We accomplished tear stimulation by the use of Allyl sulphide, a non-toxic organic compound. We measured lactoferrin by the radial immuno-diffusion technique.
Results: We found a significant decrease of lactoferrin levels in the tears of patients with giant papillary conjunctivitis.
Li Lim, FRCS; Tze Pin Ng, MFPHM, FACOM, MD; Donald Tiang Hwee Tan, FRCS, FRCOphth
Purpose: The purpose of this study was to evaluate a modified technique of Goldmann applanation tonometry without the use of fluorescein or anesthesia in normal eyes with contact lenses and to compare this technique with Tono-Pen tonometry.
Methods: The intraocular pressure (IOP) of 40 normal eyes from 20 volunteers (mean age 25.6 years, range 22–35 years) was measured with and without –1.0 D disposable soft contact lenses in a prospective, masked, randomized study using Goldmann and Tono-Pen tonometry. Goldmann tonometry was performed without fluorescein or anesthesia with contact lenses on. IOP measurement using conventional Goldmann tonometry with fluorescein and without contact lens wear was employed as the standard for comparison.
Results: Goldmann tonometry without fluorescein underestimated IOP levels in a consistent manner, with a bias of –2.15 mmHg ( SD ± 1.97). Goldmann tonometry without fluorescein, in the presence of a contact lens, consistently underestimated IOP levels by –2.90 mmHg (SD ± 2.37), suggesting that IOP measurement is largely unaffected by the presence of a –1.00 D soft contact lens on the eye. In contrast, Tono-Pen tonometry consistently overestimated IOP levels by +3.93 mmHg (SD± 2.17). Given the limits of agreement, these results were fairly consistent.
Conclusions: The modified technique of Goldmann tonometry without fluorescein reflects standard Goldmann tonometry with fluorescein after a correction factor of +2 mmHg in normal eyes. IOP measurement by this technique does not appear to be significantly affected by the presence of a –1.0 D soft contact lens on the cornea.
Kiyoshi Watanabe, MD ;Hikaru Hamano, MD
Purpose: We investigated both the incidence and types of corneal epithelial complications associated with extended wear of the Acuvue disposable soft contact lens, in particular with respect to risk factors for the typical pattern of superficial punctate keratopathy (SPK).
Methods: We conducted a retrospective study of 5,478 eyes. Clinical characteristics of the corneal epithelial complications, tear volumes, and patient compliance were analyzed.
Results: A total of 3.6% (197 eyes/5,478 eyes) were observed to have a corneal epithelial complication on at least one examination during the entire follow-up period. Among the 197 eyes, 112 eyes were observed to have a complication during the initial 2 weeks of trial lens use. This included nine eyes that developed SPK with only daily wear use of the lenses. Sixty-eight eyes were beginners with no previous contact lens experience. SPK was observed in 193 eyes and corneal infiltrates in four eyes, although there were no cases of corneal epithelial erosion or corneal ulcer. With respect to type of SPK, a "smile mark" pattern confined to the area below the pupil was observed in 179 eyes (3.3%).
Conclusions: The typical pattern of SPK was observed in 3.3% of users of extended wear disposable soft contact lenses, although the condition usually improved with the use of artificial tears.
H. Jay Bruninga, MD, OD; Robert W. Enzenauer, MD, MPH; Randall S. Robbs, MBA
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Purpose: To determine opinions and knowledge of southern Illinois eyecare patients about the different types of eyecare providers and the services they perform.
Methods: A two page survey (Appendix) was presented to 500 consecutive patients registering at the Southern Illinois University Eye Center in April, 1995. Patients were asked to respond to questions which tested their knowledge of the type of provider they were to visit, i.e., ophthalmologist, optometrist, or optician and the services provided.
Results: There was pronounced confusion and uncertainty especially with regard to the terms "ophthalmologist" and "optometrist." Approximately one-quarter of those polled believed an optometrist to be a physician, and another one-quarter was unsure. Only one-third of those surveyed reported that "OD" referred to "optometrist." Approximately one-third were unsure if an optician was a physician. Over eighty percent felt there was confusion concerning the different types of eyecare providers and only 49% felt they were well informed with regard to providers and their services.
Conclusion: The public, even among eyecare patients, is poorly informed with regard to the different types of eyecare providers and their services.
Having just returned from participating in the 42nd Annual Contact Lens Society of America (CLSA) Meeting I want to offer my congratulations to Mark Andre of Portland, Oregon for organizing a quality scientific program. The breadth and depth of the educational content offered at the meeting was truly impressive. The Association of Technical Personnel in Ophthalmology's (ATPO) presence at the meeting allowed an even wider scope of workshops and courses.
A highlight of the Meeting was a session taught by Pat Caroline and Mark Andre, both familiar faces to those of you who regularly attend the CLAO Annual Meeting. Their presentation, entitled "Contact Lens Options on Video...You Make the Call," used video to educate contact lens fitters. This format effectively showed the dynamic aspects of the contact lens fitting process, the various contact lens options for the patient, and the interaction between patient and fitter.
The annual Kevin Tuohy Lecture was given by Susan Connelly of Minneapolis, also an active participant in CLAO. Her presentation, "Communication is a Two Way Speak," cleverly used audience participation and video interaction to convey to the audience the do's and don'ts of effective communication. The content of her presentation, as well as her delivery, was superb.
This year's CLSA Meeting added a new feature—the Manufacturers Breakfast Seminar—which has been so successful at the CLAO Annual Meeting. This program, as it is at CLAO, was very attractive to both the attendees and the manufacturers. The attendance at the breakfast seminars far exceeded the expectations of the CLSA program committee.
CLAO and CLSA have a long and synergistic relationship, with education as their common goal. Each organization takes pride in the variety and quality of its educational programs and each organizes a symposium as part of the other's annual meeting. The CLSA symposium at the CLAO Annual Meeting has become an integral part of the meeting; likewise, the CLAO symposium at the CLSA Meeting is an added benefit to the attendees. These forums provide an excellent opportunity for learning from each organization's specific area of expertise. CLAO's symposium at the CLSA Meeting was entitled "Refractive Surgery Today and Tomorrow" and consisted of lectures by Dr. Bruce Bodner (Radial Keratotomy: Current and Future Trends); Dr. Peter Kastl (Contact Lens Fitting After Refractive Surgery); and myself (Refractive Surgery Beyond Radial Keratotomy). The symposium provided a well balanced discussion on the present status of refractive surgery and the continued need for contact lenses as an option for correcting vision, both as an alternative to refractive surgery and as a means for refining, if not actually solving, complications following refractive surgery.
The mission of CLAO—"To enhance quality medical eyecare by providing comprehensive ophthalmologists and other eyecare professionals with education and training in contact lenses, refractive surgery, and related eyecare science"— is fulfilled by the activities of CLAO in its publications, its Annual Meeting, its Journal, and its participation in meetings such as the CLSA Meeting.
Congratulations again to the CLSA organizers for a very informative and enjoyable meeting. The dedication of the leadership and the enthusiasm of their membership make it a truly dynamic organization. I look forward to the continued relationship between CLAO and the CLSA.
Peter C. Donshik, MD, Editor-in-Chief
the American population that bodes well for ophthalmology now and for the foreseeable future. Just as baby boomers caused more elementary schools to be built in 1957 than in any other year before or since and were the reason more colleges were opened in 1967 than in any other year, these same individuals are now swelling the ranks of the presbyopic population. With 77 million individuals born between 1946 and 1964, every seven seconds between 1996 and 2014 another baby boomer will turn 50.
Many in this population may have never experienced vision problems prior to their presbyopic symptoms and thus may have had few, if any, regular eye examinations. But as we know from past experience, presbyopes regularly visit our offices so that they may upgrade their reading glasses, bifocals, or contact lenses. So a significant increase in the presbyopic population is good news for ophthalmology. In an era in which subspecialties like pediatrics are less in demand because of population demographics, and with fewer surgical subspecialties required because of managed care, ophthalmology is well-positioned to reap the benefits from treating the baby boom generation.
What we learned about presby-opes during our ophthalmology residency training ten, twenty, thirty, or even forty years ago should be pushed aside, and we must learn again about age related vision changes, especially decline of accommodation, senile miosis, loss of visual acuity, lowered contrast sensitivity, increased lighting sensitivity, and slower speed of visual processing and how these affect this emerging new population of presbyopes differently than previous generations. This generation of presbyopes looks, acts, and feels differently than any previous generation. We cannot dismiss or make light of their concerns with growing older if we expect to keep them as patients. They are individualistic, curious, and information-oriented, demanding of value, embracing of technology, impulsive, opinionated, educated, active, environmentally aware, health conscious, and interested in quality, consistency, convenience, and comfort.
We must explain to them what presbyopia is and what we can do about it. While they might resent presbyopia and deny it as long as possible, we must let them know that we appreciate and value their decision to seek treatment in our practice. We need to educate patients about the need for regular vision examinations. It is much less expensive to keep an established patient in your practice than to admit a new patient. Remember that today's presbyope is tomorrow's cataract patient. Think of the increased number of potential cataract patients in your practice 10 or 20 years from now if you see and treat these patients now.
Sometimes people go looking far and wide for what may be right under their noses. What is happening in ophthalmology right now is a case in point. Ophthalmologists are looking hither and yon for ways to return their incomes to pre-1985 levels, before the significant reductions began in Medicare reimbursements for cataract surgery. One irrefutable fact of managed care's impact upon medicine is that proceduralists such as surgeons are no longer needed in such numbers and will no longer be paid as much as they once were. Unlike other subspecialists who may find themselves having to be retrained into a primary care specialty, ophthalmologists in the new managed care environment can simply take their skills and use them on the emerging presbyopic population. Ophthalmology should consider itself fortunate and take advantage of this emerging opportunity.
James D. Atwood, MD, Sacramento, CA
1994 CLAO President
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Copyright 1997 Contact
Lens Association of Ophthalmologists, Inc.