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Bitoric rigid gas permeable contact lenses to improve vision following iris melanoma excision
Clinical Article
Bitoric Rigid Gas Permeable Contact Lenses to Improve Vision Following Iris Melanoma Excision Barry A. Weissman,
OD,
PhD,
Wilson
Bitoric rigid gas permeable knses were fitted to one eye each of two femak patients who had both prewiously undergone iris melanoma surgical excision. The surgical process resulted in the genesis of cornea1 and refractive astigmatism, which was not optimally optically corrected with spectucks. Bitoric rigid gas permeabk contact lenses were both physiologically tokrated and improved vision in these instances. Keywords: Rigid contact lenses; astigmatism; power effect; cylindrical
bitoric; power effect; iris melanoma
spherical
Introduction Bitoric rigid contact lens designs have been used for many years to improve mechanical contact lens application in instances of cornea1 astigmatism. The descriptions of “spherical power effect” (SPE) and “cylinder power effect” (CPE) (bitoric rigid contact lenses) were introduced by Sarver to simplify the design of such lenses.’ SPE implies that toricity is produced on the base-curve side of the lens to address the fitting requirements of the astigmatic cornea1 surface, and then the overall power of the lens is adjusted by toricity on its front surface in each of the two principal meridians to exactly neutralize the lens/tear layer interface power change. The result is a lens that, while offering improved fitting characteristics on an astigmatic cornea1
Wu,
MD,
PhD,
and Bartly
J. Mondino,
MD
surface, simulates the optical power effect of a spherical rigid lens. If residual refractive astigmatism is still manifest, however, and in alignment with the meridians of optical pow&, a CPE lens may be prescribed with the same mechanical fitting properties but with different powers in the major meridians to address the optical requirements; the only disadvantage is a loss of optical stability with lens rotation in this latter case. A third type of toric rigid lens would be a front surface toric, but this will not be further considered here. Sarver et a1.,2 and later Weissman and Chun,3 applied this concept to new rigid gas permeable lenses, and both suggested that more than 80% of patients requiring toric rigid lenses could be managed with the simpler SPE design. Weissman and Chun reported the application of both bitoric designs to a large series of both “developmental” and “acquired” (through some disease or surgical process) astigmatic eyes.3 The disease processes that induced cornea1 astigmatism discussed in this latter study included keratoconus, cornea1 grafts, cataract extraction, and cornea1 trauma. This report adds an additional indication to this group: Two patients are described who acquired cornea1 astigmatism following the removal of iris melanomas and who were visually rehabilitated with these rigid contact lens designs.
Case Reports Address reprint requests to Dr. Barry A. Weissman at the Jules Stein Eye Institute, and Department of Ophthalmology, UCLA School of Medicine, Los Angeles, CA 90024-7003. Accepted for publication May 11, 1992.
210
ICLC, Vol. 19, September/October
1992
Case 1 A 28-year-old woman was examined initially on January 28, 1990, on referral for contact lens fitting of her left eye.
0 1992 Butterworth-Heinemann
Bitoric RGPs: Weissman et al. She had undergone excision of an iris melanoma from her left eye on October 2, 1975. Surgery was performed through a 5 clock-hour limbal scleral incision (12:45 to 5:45 o’clock meridians). Visual rehabilitation had only been attempted on one occasion; a Saturn II@ lens had been applied by another practitioner but was not physically tolerated by the patient. Unaided visions were OD 20/20 and OS 20/300, and vision in the left eye improved with an astigmatic refraction: OS +3.00
= +2.00
Cornea1 curvatures
x 180
20180.
were measured at
OD 43.00/44.00/180 OS 41.25/47.00/180. Keratometry mires were clear in both eyes. The clarity of cornea1 topography of the left eye, and its with-the-rule astigmatic nature, were confirmed by photoelectrokeratoscopy (PEK) (FigLcre 1). External ocular evaluation was unremarkable. Biomicroscopy disclosed a sector temporal iridectomy that extended from 12:45 to 5:30, consistent with the previous surgery (see Figure 1). Use of a diagnostic spherical power effect bitoric lens (8.13/7.58 pl/- 3.00 9.0 Polycon II@) suggested an excellent with-the-rule band alignment fit, with good movement and centration. Overrefraction suggested need for spherocylindrical correction: OS +2.25
= +l.OO
x 90
20120.
This patient was very pleased with the visual and comfort results of the diagnostic analysis. She was primarily interested in visual rehabilitation; she understood that this effort would not be to cosmetically improve the appearance of her iris abnormality. A cylinder power effect bitoric rigid gas permeable lens was therefore ordered for this patient’s left eye:
Figure 2. Bitoric rigid gas permeable contact lens on the left eye of Case 1. Note excellent centration and position, uniform fluorescein pattern, and inferior dot. A superior dot is hidden under the upper lid. These dots serve to identify the steep axis of the lens for the clinician, to assist in optical power and fit modifications. OS 8.13/7.58 +3.75/-0.25 9.4 STD edge RGP, dark blue with UV filter, DK’ 30. The specific material was elected because it allowed the clinician to combine good oxygen transmissibility with a dark blue tint and a UV filter to decrease both subjective glare and, prophylactically, UV exposure to the patient’s ocular tissues s-7 with the lens in place. This lens was dispensed on February 16, 1990. Vision was 20/20and improved slightly with an optical power change of - 0.50 DS to 20/20 + . The patient was trained in lens care and advised to slowly increase wearing time to a maximum of 4 hours/day. On progress evaluation on March 6, 1990, however, the patient presented at 6 hours/ day wear and with vision of 20/15 without overcorrection. No change in lens was therefore made. No mechanical or physiological difficulties were noted, and tolerance was excellent. Progress continued through several additional progress evaluations (final examination was in November 1990), at which time the patient was comfortably wearing this lens 11 hours/day without difficulties. Figure 2 shows the final lens in place on this eye. Case 2 Our second patient, also female, was 22 years of age at initial presentation on July 6, 1982, with an iris tumor of the right eye. Progressive growth was documented, and she underwent excisional biopsy on April 13, 1990. She had no
Dk is defined as oxygen permeability of the contact lens material used, here as originally specified by the manufacturer. Units are x 1O-9 cm ml O,/second ml mmHg. Such values were not confirmed here, and, indeed, in general, have been found to vary from that originally presented by the manufacturer.4 ??
Figure 1. Photokeratogram of the cornea1 surface from the left eye of Case 1. Note the temporal loss of iris and the highly astigmatic, with-the-rule, but regular nature of the mires.
ICLC, Vol. 19, September/October
1992
211
ClinicalArticles forward spectacles were also ordered with pl in the right and maximum correction determined above by refraction in the left, to be made from polycarbonate to maximize physical protection to both eyes. On dispensing of the contact lens on March 14, 1991, OD vision was found to be 20/30 - , but improved with an additional -0.50 DS to 20/25. The lens was seen to ride somewhat superior and temporal, and central bearing was considered slightly excessive (Figure 4). The patient was instructed in lens care, and this lens was dispensed to be used for minimum wear (l-2 hours/day only) while a second lens was ordered:
Figure 3. Photokeratogram of the comeal surface from the right eye of Case 2. Note the loss of iris tissue from the nasal to the inferior aspect of the cornea and the highly astigmatic nature of the mires. Also (at black arrow), note localized distortion peripherally.
history of any previous contact lens experience and was referred for contact lens consideration on January 24, 1991. Unaided visions were OD 20/125 and OS 20120 - . Refraction was OD -2.00 = +4.50 OS - 1.00 = +0.50
x 40 x 10
20180 + 20/15.
Comeal curvatures were OD 48.00/39.50/30 (slightly dis torted) and OS 44.50/44.25/180 (clear mires). Photokeratoscopy confirmed cornea1 astigmatism OD (Figure 3); reflection off the right cornea showed some irregularity, especially over the inferionasal aspect of the car, nea. It was known that the surgeon had removed a portion of the cornea1 endothelium and Descemet’s membrane, which could not be separated from the tumor, in this area. Some cornea1 staining and scarring were observed in this same site. Biomicroscopy of this eye also showed a loss of iris over about 250”, in this instance centered about the inferionasal aspect (see Figure 3). A diagnostic bitoric lens was used: 8.3317.76 pV- 2.00 9.0 Polycon II. With this diagnostic lens on the eye, +3.00 DS subjectively resulted in 20/30 vision. Fluorescein evaluation suggested some irregular central touch but good movement, tear exchange, and centration. Again this patient, after discussion, elected visual rehabilitation over cosmesis, and a spherical power effect (SPE) bitoric lens fitting was initiated after obtaining informed consent. The first lens order was OD 8.39/7.76 + 3.25/pl 9.2 STD edge RGP, dark blue with UV filter, DK 60. Because the patient took some minor refractive correction in the left eye (see refraction results above), and with full optical contact lens correction OD did not achieve 20/20,
212
ICLC, Vol. 19, September/October
1992
OD 8.3917.76 +2.75/-0.25 9.45 STD edge RGP, dark blue with UV filter, Dk 60. This lens differed from the first lens only in optical power, incorporating the refractive change noted above, and in slightly increased diameter to improve mechanical centration and alignment. The patient was seen for a progress evaluation on March 28, 1991, at which the above were confirmed, and as the patient appeared to be successfully tolerating the lens fit, the second lens was dispensed. This showed a clearly improved mechanical fit (Figure 5), and vision improved to 20130 + . Tolerance improved and vision was stable over the next several months. A suture was noted to have eroded through the conjunctiva on April 25, 1991, and was removed by her referring ophthalmologist. Most recently, a bullae formed in the inferiotemporal scar seen previously, and lens wear has had to be temporarily discontinued. Wearing time in June 1991, however, was 12 hours per day, with good tolerance and vision of 20/25 + .
Figure 4. The first bitoric rigid gas permeable lens on the right eye of Case 2. The lens decenters temporally; also shown is staining and distortion of the peripheral nasal cornea (at black arrow) corresponding to the site of damage to the endothelium and Descemet’s that was necessitated during surgical removal of the entire tumor.
Bittic
Figure 5. The second bitoric lens on the right eye of Case 2. This lens shows improved centration; see text for fitting changes. Light pan-cornea1 stain was a minor asymptomatic contact lens solution reaction that was effectively managed by changing care systems.
Discussion
RGPs: Weissrnun et al.
should be high on the list of possible treatment modalities when a clinician is faced with difficulties in improving vision in any instance of regular or irregular, developmental or acquired, cornea1 astigmatism. It is also important to note that such lens care does not assist in the cosmetic rehabilitation of such patients. The appearance of iris defects such as our patients presented are not in any way improved by use of rigid lenses, although glare and UV exposure may be minimized by appropriate choice of lens tints and dyes. Alternatives for cosmetic enhancement are available in opaque hydrogel lens formats,8 but do not necessarily assist in visual improvement. For the present level of technology, in many instances, patients and clinicians are forced to choose between visual or cosmetic correction. Recent studies of patients who have had iridocyclectomy procedures for iris melanomas suggest that the outcomes are generally favorable. 9, lo We present two patients who, following successful surgical iris melanoma removal, suffered visual loss that was addressed clinically by use of bitoric rigid gas permeable lenses with restoration of vision to normal levels. References
Neither
of these
patients
had
been
prior
to
Comparison of cur, rent keratometry values between the two eyes of each patient, and history of previously normal vision, however, suggests that the astigmatism found in both these eyes was indeed surgically induced. It is also interesting to note that both of these eyes obtained maximum visions of 20/80 with best spectacle correction, but improved to almost normal vision in both instances with rigid contact lens correction; it is clear that the contact lenses not only addressed the and probable secondary aniseikonia, but anisometropia, also improved vision by regularizing the cornea1 surface. This occurred even in the eye in which neither keratometry nor photokeratoscopy detected cornea1 surface irregularity. The clinical efficacy of such contact lens care in these two instances is clear. Visual rehabilitation would not have occurred without the use of contact lenses and probably would have been less satisfactory with other contact lens alternatives such as spherical rigid, toric hydrogel, or hybrid designs (the latter, indeed, had failed to help the first patient)-although, to be fair, it is possible that any of these options might be indicated in any specific case, depending on clinical circumstances. Thus, we believe that SPE and CPE design rigid lenses their
intraocular
tumors
and surgery.
examined
1. Sarver MD: A toric base curve comeal contact lens with spherical power effect. J Am Optom Assoc 1963;34:11361137. 2. Sarver MD, Kame RT, Williams CT: A bitoric gas permeable hard contact lens with spherical power effect. J Am Opom Assoc 1985;56:184-189. 3. Weissman BA, Chun MW: The use of spherical power effect bitoric rigid contact lenses in hospital practice. J Am OPtom Assoc 1987;58:626-630. 4. Fatt I, Rasson JE, Melpolder JB: Measuring oxygen permeability of gas permeable hard and hydrogel lenses and flat samples in air. lCLC 1987;14:389-401. 5. Young RW: Solar radiation and age-related macular degeneration. Sure OPhthalmol 1988;32:252-269. 6. Zigman S, Datiles M, Torczynski G: Sunlight and human cataracts. Invest OPhthulmol Vis Sci 1979;18:462467. 7. Pitts DG, Bergmanson JP, Chu LW-F: Ultrastructural analysis of comeal exposure to UV radiation. Acm Ophthulmol 1987;65:263-273. a. Shovlin JP, Meshel LG, Weissman BA, DePaolis MD: Tinted contact lenses: Cosmetic and prosthetic application, in Bennett ES, Weissman BA (Eds): Clinical Contact Lens Practice. Philadelphia, J. B. Lippincott, 1991. 9. Arentsen JJ, Green WR: Melanoma of the iris: Report of 72 cases treated surgically. Ophtkrl Surg 1975;6:23-37. 10. Memmen JE, McLean IW: The long term outcome of patients undergoing iridocyclectomy. Ophthalmology 199~97: 429432.
ICLC, Vol. 19, September/October
1992
213
Clinical Articles Dr. Barry A. Weissman was educated at the School of Optometry, University of California, Berkeley, receiving his OD in 1972 and PhD in physiological optics in 1979. He has experience in private practice and was also a member of the Contact Lens Service of HadassahHebrew University Hospital, Jerusalem, Israel, for over 1 year. Dr. Weissman is currently a professor of ophthalmology at the Jules Stein Eye Institute, UCLA School of Medicine, and chief of Contact Lens Service there. He is a Fellow of the American Academy of Optometry and a Diplomate in its Cornea-Contact Lens Section and a member of the International Society for Contact Lens Research. Current research interests include oxygen delivery to the cornea, mathematical modeling of hydrogel flexure, and complications (especially infection) associated with contact lens wear. He is author of a manual on contact lens care: Contact Lens Primer, co-editor of a textbook Clinical Contact Lens Practice with Edward S. Bennett, OD, MSEd, published by J.B. Lippincott in 1991, and also coauthor with Professor Irving Fatt of the second edition of Physiology of the Eye; CMIIntroduction to Vegetative Functions to be published by Butterworth-Heinemann in 1992. Dr. Wu received his bachelor of science degree in biochemistry from the University of California, Los Angeles. He obtained his medical training at Harvard Medical School. He also completed graduate train+ ing and obtained a PhD in biochemistry and molecular biology from the California Institute of Technology. After this training, he was awarded the Jane Coffin Childs Foundation Research Fellowship and spent 2 years conducting basic research in synaptic transmission at the Yale University School of Medicine. Dr. Wu is currently a Heed clinical fellow, specializing in comeal and external disease, at the Jules Stein Eye Institute. He is an author of 23 original publications. Dr. Bartly J. Mondino received his BA and MD from Stanford University. After completing his internship, he was a resident in ophthalmology at New York Hospital-Cornell University. Afterward, he was a fellow at the University of Pittsburgh for 1 year and continued there as an assistant and then an associate professor. For the past 10 years, Dr. Mondino has been on the faculty of the Jules Stein Eye Institute, UCLA School of Medicine. He is currently Wasserman Professor of Ophthalmology and vice-chairman of the Department. He is a member of the Cornea-External Disease Division of which he is chief. He has over 150 full-length publications and several research grants. He is interested in cornea-external diseases, anterior segment surgery, and immunologic and inflammatory diseases of the eye.
214
ICLC, Vol. 19, September/October
1992
Bitoric Rigid Gas Permeable Contact Lenses to Improve Vision Following Iris Melanoma Excision Barry A. Weissman,
OD,
PhD,
Wilson
Bitoric rigid gas permeable knses were fitted to one eye each of two femak patients who had both prewiously undergone iris melanoma surgical excision. The surgical process resulted in the genesis of cornea1 and refractive astigmatism, which was not optimally optically corrected with spectucks. Bitoric rigid gas permeabk contact lenses were both physiologically tokrated and improved vision in these instances. Keywords: Rigid contact lenses; astigmatism; power effect; cylindrical
bitoric; power effect; iris melanoma
spherical
Introduction Bitoric rigid contact lens designs have been used for many years to improve mechanical contact lens application in instances of cornea1 astigmatism. The descriptions of “spherical power effect” (SPE) and “cylinder power effect” (CPE) (bitoric rigid contact lenses) were introduced by Sarver to simplify the design of such lenses.’ SPE implies that toricity is produced on the base-curve side of the lens to address the fitting requirements of the astigmatic cornea1 surface, and then the overall power of the lens is adjusted by toricity on its front surface in each of the two principal meridians to exactly neutralize the lens/tear layer interface power change. The result is a lens that, while offering improved fitting characteristics on an astigmatic cornea1
Wu,
MD,
PhD,
and Bartly
J. Mondino,
MD
surface, simulates the optical power effect of a spherical rigid lens. If residual refractive astigmatism is still manifest, however, and in alignment with the meridians of optical pow&, a CPE lens may be prescribed with the same mechanical fitting properties but with different powers in the major meridians to address the optical requirements; the only disadvantage is a loss of optical stability with lens rotation in this latter case. A third type of toric rigid lens would be a front surface toric, but this will not be further considered here. Sarver et a1.,2 and later Weissman and Chun,3 applied this concept to new rigid gas permeable lenses, and both suggested that more than 80% of patients requiring toric rigid lenses could be managed with the simpler SPE design. Weissman and Chun reported the application of both bitoric designs to a large series of both “developmental” and “acquired” (through some disease or surgical process) astigmatic eyes.3 The disease processes that induced cornea1 astigmatism discussed in this latter study included keratoconus, cornea1 grafts, cataract extraction, and cornea1 trauma. This report adds an additional indication to this group: Two patients are described who acquired cornea1 astigmatism following the removal of iris melanomas and who were visually rehabilitated with these rigid contact lens designs.
Case Reports Address reprint requests to Dr. Barry A. Weissman at the Jules Stein Eye Institute, and Department of Ophthalmology, UCLA School of Medicine, Los Angeles, CA 90024-7003. Accepted for publication May 11, 1992.
210
ICLC, Vol. 19, September/October
1992
Case 1 A 28-year-old woman was examined initially on January 28, 1990, on referral for contact lens fitting of her left eye.
0 1992 Butterworth-Heinemann
Bitoric RGPs: Weissman et al. She had undergone excision of an iris melanoma from her left eye on October 2, 1975. Surgery was performed through a 5 clock-hour limbal scleral incision (12:45 to 5:45 o’clock meridians). Visual rehabilitation had only been attempted on one occasion; a Saturn II@ lens had been applied by another practitioner but was not physically tolerated by the patient. Unaided visions were OD 20/20 and OS 20/300, and vision in the left eye improved with an astigmatic refraction: OS +3.00
= +2.00
Cornea1 curvatures
x 180
20180.
were measured at
OD 43.00/44.00/180 OS 41.25/47.00/180. Keratometry mires were clear in both eyes. The clarity of cornea1 topography of the left eye, and its with-the-rule astigmatic nature, were confirmed by photoelectrokeratoscopy (PEK) (FigLcre 1). External ocular evaluation was unremarkable. Biomicroscopy disclosed a sector temporal iridectomy that extended from 12:45 to 5:30, consistent with the previous surgery (see Figure 1). Use of a diagnostic spherical power effect bitoric lens (8.13/7.58 pl/- 3.00 9.0 Polycon II@) suggested an excellent with-the-rule band alignment fit, with good movement and centration. Overrefraction suggested need for spherocylindrical correction: OS +2.25
= +l.OO
x 90
20120.
This patient was very pleased with the visual and comfort results of the diagnostic analysis. She was primarily interested in visual rehabilitation; she understood that this effort would not be to cosmetically improve the appearance of her iris abnormality. A cylinder power effect bitoric rigid gas permeable lens was therefore ordered for this patient’s left eye:
Figure 2. Bitoric rigid gas permeable contact lens on the left eye of Case 1. Note excellent centration and position, uniform fluorescein pattern, and inferior dot. A superior dot is hidden under the upper lid. These dots serve to identify the steep axis of the lens for the clinician, to assist in optical power and fit modifications. OS 8.13/7.58 +3.75/-0.25 9.4 STD edge RGP, dark blue with UV filter, DK’ 30. The specific material was elected because it allowed the clinician to combine good oxygen transmissibility with a dark blue tint and a UV filter to decrease both subjective glare and, prophylactically, UV exposure to the patient’s ocular tissues s-7 with the lens in place. This lens was dispensed on February 16, 1990. Vision was 20/20and improved slightly with an optical power change of - 0.50 DS to 20/20 + . The patient was trained in lens care and advised to slowly increase wearing time to a maximum of 4 hours/day. On progress evaluation on March 6, 1990, however, the patient presented at 6 hours/ day wear and with vision of 20/15 without overcorrection. No change in lens was therefore made. No mechanical or physiological difficulties were noted, and tolerance was excellent. Progress continued through several additional progress evaluations (final examination was in November 1990), at which time the patient was comfortably wearing this lens 11 hours/day without difficulties. Figure 2 shows the final lens in place on this eye. Case 2 Our second patient, also female, was 22 years of age at initial presentation on July 6, 1982, with an iris tumor of the right eye. Progressive growth was documented, and she underwent excisional biopsy on April 13, 1990. She had no
Dk is defined as oxygen permeability of the contact lens material used, here as originally specified by the manufacturer. Units are x 1O-9 cm ml O,/second ml mmHg. Such values were not confirmed here, and, indeed, in general, have been found to vary from that originally presented by the manufacturer.4 ??
Figure 1. Photokeratogram of the cornea1 surface from the left eye of Case 1. Note the temporal loss of iris and the highly astigmatic, with-the-rule, but regular nature of the mires.
ICLC, Vol. 19, September/October
1992
211
ClinicalArticles forward spectacles were also ordered with pl in the right and maximum correction determined above by refraction in the left, to be made from polycarbonate to maximize physical protection to both eyes. On dispensing of the contact lens on March 14, 1991, OD vision was found to be 20/30 - , but improved with an additional -0.50 DS to 20/25. The lens was seen to ride somewhat superior and temporal, and central bearing was considered slightly excessive (Figure 4). The patient was instructed in lens care, and this lens was dispensed to be used for minimum wear (l-2 hours/day only) while a second lens was ordered:
Figure 3. Photokeratogram of the comeal surface from the right eye of Case 2. Note the loss of iris tissue from the nasal to the inferior aspect of the cornea and the highly astigmatic nature of the mires. Also (at black arrow), note localized distortion peripherally.
history of any previous contact lens experience and was referred for contact lens consideration on January 24, 1991. Unaided visions were OD 20/125 and OS 20120 - . Refraction was OD -2.00 = +4.50 OS - 1.00 = +0.50
x 40 x 10
20180 + 20/15.
Comeal curvatures were OD 48.00/39.50/30 (slightly dis torted) and OS 44.50/44.25/180 (clear mires). Photokeratoscopy confirmed cornea1 astigmatism OD (Figure 3); reflection off the right cornea showed some irregularity, especially over the inferionasal aspect of the car, nea. It was known that the surgeon had removed a portion of the cornea1 endothelium and Descemet’s membrane, which could not be separated from the tumor, in this area. Some cornea1 staining and scarring were observed in this same site. Biomicroscopy of this eye also showed a loss of iris over about 250”, in this instance centered about the inferionasal aspect (see Figure 3). A diagnostic bitoric lens was used: 8.3317.76 pV- 2.00 9.0 Polycon II. With this diagnostic lens on the eye, +3.00 DS subjectively resulted in 20/30 vision. Fluorescein evaluation suggested some irregular central touch but good movement, tear exchange, and centration. Again this patient, after discussion, elected visual rehabilitation over cosmesis, and a spherical power effect (SPE) bitoric lens fitting was initiated after obtaining informed consent. The first lens order was OD 8.39/7.76 + 3.25/pl 9.2 STD edge RGP, dark blue with UV filter, DK 60. Because the patient took some minor refractive correction in the left eye (see refraction results above), and with full optical contact lens correction OD did not achieve 20/20,
212
ICLC, Vol. 19, September/October
1992
OD 8.3917.76 +2.75/-0.25 9.45 STD edge RGP, dark blue with UV filter, Dk 60. This lens differed from the first lens only in optical power, incorporating the refractive change noted above, and in slightly increased diameter to improve mechanical centration and alignment. The patient was seen for a progress evaluation on March 28, 1991, at which the above were confirmed, and as the patient appeared to be successfully tolerating the lens fit, the second lens was dispensed. This showed a clearly improved mechanical fit (Figure 5), and vision improved to 20130 + . Tolerance improved and vision was stable over the next several months. A suture was noted to have eroded through the conjunctiva on April 25, 1991, and was removed by her referring ophthalmologist. Most recently, a bullae formed in the inferiotemporal scar seen previously, and lens wear has had to be temporarily discontinued. Wearing time in June 1991, however, was 12 hours per day, with good tolerance and vision of 20/25 + .
Figure 4. The first bitoric rigid gas permeable lens on the right eye of Case 2. The lens decenters temporally; also shown is staining and distortion of the peripheral nasal cornea (at black arrow) corresponding to the site of damage to the endothelium and Descemet’s that was necessitated during surgical removal of the entire tumor.
Bittic
Figure 5. The second bitoric lens on the right eye of Case 2. This lens shows improved centration; see text for fitting changes. Light pan-cornea1 stain was a minor asymptomatic contact lens solution reaction that was effectively managed by changing care systems.
Discussion
RGPs: Weissrnun et al.
should be high on the list of possible treatment modalities when a clinician is faced with difficulties in improving vision in any instance of regular or irregular, developmental or acquired, cornea1 astigmatism. It is also important to note that such lens care does not assist in the cosmetic rehabilitation of such patients. The appearance of iris defects such as our patients presented are not in any way improved by use of rigid lenses, although glare and UV exposure may be minimized by appropriate choice of lens tints and dyes. Alternatives for cosmetic enhancement are available in opaque hydrogel lens formats,8 but do not necessarily assist in visual improvement. For the present level of technology, in many instances, patients and clinicians are forced to choose between visual or cosmetic correction. Recent studies of patients who have had iridocyclectomy procedures for iris melanomas suggest that the outcomes are generally favorable. 9, lo We present two patients who, following successful surgical iris melanoma removal, suffered visual loss that was addressed clinically by use of bitoric rigid gas permeable lenses with restoration of vision to normal levels. References
Neither
of these
patients
had
been
prior
to
Comparison of cur, rent keratometry values between the two eyes of each patient, and history of previously normal vision, however, suggests that the astigmatism found in both these eyes was indeed surgically induced. It is also interesting to note that both of these eyes obtained maximum visions of 20/80 with best spectacle correction, but improved to almost normal vision in both instances with rigid contact lens correction; it is clear that the contact lenses not only addressed the and probable secondary aniseikonia, but anisometropia, also improved vision by regularizing the cornea1 surface. This occurred even in the eye in which neither keratometry nor photokeratoscopy detected cornea1 surface irregularity. The clinical efficacy of such contact lens care in these two instances is clear. Visual rehabilitation would not have occurred without the use of contact lenses and probably would have been less satisfactory with other contact lens alternatives such as spherical rigid, toric hydrogel, or hybrid designs (the latter, indeed, had failed to help the first patient)-although, to be fair, it is possible that any of these options might be indicated in any specific case, depending on clinical circumstances. Thus, we believe that SPE and CPE design rigid lenses their
intraocular
tumors
and surgery.
examined
1. Sarver MD: A toric base curve comeal contact lens with spherical power effect. J Am Optom Assoc 1963;34:11361137. 2. Sarver MD, Kame RT, Williams CT: A bitoric gas permeable hard contact lens with spherical power effect. J Am Opom Assoc 1985;56:184-189. 3. Weissman BA, Chun MW: The use of spherical power effect bitoric rigid contact lenses in hospital practice. J Am OPtom Assoc 1987;58:626-630. 4. Fatt I, Rasson JE, Melpolder JB: Measuring oxygen permeability of gas permeable hard and hydrogel lenses and flat samples in air. lCLC 1987;14:389-401. 5. Young RW: Solar radiation and age-related macular degeneration. Sure OPhthalmol 1988;32:252-269. 6. Zigman S, Datiles M, Torczynski G: Sunlight and human cataracts. Invest OPhthulmol Vis Sci 1979;18:462467. 7. Pitts DG, Bergmanson JP, Chu LW-F: Ultrastructural analysis of comeal exposure to UV radiation. Acm Ophthulmol 1987;65:263-273. a. Shovlin JP, Meshel LG, Weissman BA, DePaolis MD: Tinted contact lenses: Cosmetic and prosthetic application, in Bennett ES, Weissman BA (Eds): Clinical Contact Lens Practice. Philadelphia, J. B. Lippincott, 1991. 9. Arentsen JJ, Green WR: Melanoma of the iris: Report of 72 cases treated surgically. Ophtkrl Surg 1975;6:23-37. 10. Memmen JE, McLean IW: The long term outcome of patients undergoing iridocyclectomy. Ophthalmology 199~97: 429432.
ICLC, Vol. 19, September/October
1992
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Clinical Articles Dr. Barry A. Weissman was educated at the School of Optometry, University of California, Berkeley, receiving his OD in 1972 and PhD in physiological optics in 1979. He has experience in private practice and was also a member of the Contact Lens Service of HadassahHebrew University Hospital, Jerusalem, Israel, for over 1 year. Dr. Weissman is currently a professor of ophthalmology at the Jules Stein Eye Institute, UCLA School of Medicine, and chief of Contact Lens Service there. He is a Fellow of the American Academy of Optometry and a Diplomate in its Cornea-Contact Lens Section and a member of the International Society for Contact Lens Research. Current research interests include oxygen delivery to the cornea, mathematical modeling of hydrogel flexure, and complications (especially infection) associated with contact lens wear. He is author of a manual on contact lens care: Contact Lens Primer, co-editor of a textbook Clinical Contact Lens Practice with Edward S. Bennett, OD, MSEd, published by J.B. Lippincott in 1991, and also coauthor with Professor Irving Fatt of the second edition of Physiology of the Eye; CMIIntroduction to Vegetative Functions to be published by Butterworth-Heinemann in 1992. Dr. Wu received his bachelor of science degree in biochemistry from the University of California, Los Angeles. He obtained his medical training at Harvard Medical School. He also completed graduate train+ ing and obtained a PhD in biochemistry and molecular biology from the California Institute of Technology. After this training, he was awarded the Jane Coffin Childs Foundation Research Fellowship and spent 2 years conducting basic research in synaptic transmission at the Yale University School of Medicine. Dr. Wu is currently a Heed clinical fellow, specializing in comeal and external disease, at the Jules Stein Eye Institute. He is an author of 23 original publications. Dr. Bartly J. Mondino received his BA and MD from Stanford University. After completing his internship, he was a resident in ophthalmology at New York Hospital-Cornell University. Afterward, he was a fellow at the University of Pittsburgh for 1 year and continued there as an assistant and then an associate professor. For the past 10 years, Dr. Mondino has been on the faculty of the Jules Stein Eye Institute, UCLA School of Medicine. He is currently Wasserman Professor of Ophthalmology and vice-chairman of the Department. He is a member of the Cornea-External Disease Division of which he is chief. He has over 150 full-length publications and several research grants. He is interested in cornea-external diseases, anterior segment surgery, and immunologic and inflammatory diseases of the eye.
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1992