- Email: [email protected]
March consultation #3
556
CONSULTATION SECTION
initially and treatment only in the case of a change in visual acuity or more pronounced topographic progression. Federico Badala, MD Milan, Italy
REFERENCES 1. Belin MW, Asota IM, Ambrosio R Jr, Khachikian SS. What’s in a name: keratoconus, pellucid marginal degeneration, and related thinning disorders. Am J Ophthalmol 2011; 152: 157–162 2. Millodot M, Shneor E, Albou S, Atlani E, Gordon-Shaag A. Prevalence and associated factors of keratoconus in Jerusalem: a cross-sectional study. Ophthalmic Epidemiol 2011; 18:91–97 3. McMonnies CW. Mechanisms of rubbing-related corneal trauma in keratoconus. Cornea 2009; 28:607–615 P, Malet F, Garra C, Gallois A, 4. Asri D, Touboul D, Fournie Malecaze F, Colin J. Corneal collagen crosslinking in progressive keratoconus: multicenter results from the French National Reference Center for Keratoconus. J Cataract Refract Surg 2011; 37:2137–2143 5. Angunawela RI, Arnalich-Montiel F, Allan BD. Peripheral sterile corneal infiltrates and melting after collagen crosslinking for keratoconus. J Cataract Refract Surg 2009; 35:606–607
Figure 4. Difference maps. Top: Right eye. Bottom: Left eye.
Should the patient's medical history be significant for intense eye rubbing, eye atopy, and related symptoms, I would counsel him regarding the possibility that simply stopping the eye rubbing might halt progression.3 I would then have him return 2 months after he begins topical treatment for atopy. Collagen crosslinking (CXL) would be my first-line intervention in the absence of a history of significant eye rubbing. Whether to recommend unilateral or bilateral CXL is a tough call in this case. I would start CXL the right eye and watch closely for further change in visual acuity or topography in the left eye. Should that happen, immediate CXL in the left eye is warranted. At present, the long-term effects of CXL for keratoconus are unknown; the ultraviolet-A (UVA) light might damage the corneal endothelial cells, lens, or retina, even though there is no evidence of this in published clinical studies. In addition, although rare, complications of the CXL procedure have been reported. These include corneal haze, corneal burns,4 bacterial and herpetic keratitis, and corneal melting.5 The patient's UDVA in the left eye is 20/20 . Thus, I would recommend follow-up visits every 2 months
- Corneal topography and scanning-slit elevation maps at baseline and 4 months later show little, if any, changes. Keratometry at 3.0 mm is 44.7 D in the right eye and 43.3 D in the left eye. The central corneal thickness (CCT) is 491 mm and 495 mm, respectively. The difference maps also appear stable with respect to axial power. Optical coherence topography confirms the presence of anterior and posterior elevation and inferotemporal thinning bilaterally. Axial curvature maps show a typical crab-claw pattern consistent with pellucid marginal degeneration (PMD). An additional test could be keratoscopy or the use of a simple handheld keratoscope, from which a pattern of “flat-flat-steep-steep-steep” ring mires can be observed progressively from the center to the inferior periphery. The progressive decline in vision could be due to an increase in accommodative demand from the intensive examinations. Nevertheless, the pattern of PMD is a concern. Despite the apparent stability of the objective tests, it is known that PMD presents in the 20- to 40-year age group and tends to progress over time. Furthermore, when inferior thinning occurs, optical and surgical options become limited. The following aspects are encouraging for surgical intervention in this case: keratometry readings less than 55.0 D, CCT greater than 400 mm, and good UDVA and CDVA. Because there is more cylinder in the right eye and the CDVA has begun to decline
J CATARACT REFRACT SURG - VOL 38, MARCH 2012
CONSULTATION SECTION
from 20/20, my approach would be summarized as follows: In the right eye, perform intrastromal corneal ring segment (ICRS) implantation inferiorly, which would be immediately followed by corneal CXL. In the left eye, perform CXL alone. The goals would be to improve UDVA and CDVA and to stabilize both eyes. For CXL, I would follow the protocol initially reported by Wollensak et al.1 In brief, a riboflavin 0.1% solution in dextran 20.0% is instilled on the deepithelialized cornea every 2 minutes for 30 minutes. This is followed by continued riboflavin instillation in the presence of UVA light (370 nm) for 30 minutes and a radiant exposure of 5.4 mJ/cm2, which corresponds to an irradiance of 3 mW/cm2. In brief, the ICRS implantation technique2 would be as follows: Create intrastromal channels using a 150 kHz femtosecond laser. Place a single 0.35 mm segment inferiorly at 400 mm depth, with a 6.8 mm internal diameter and a 7.8 mm external diameter. The location of the incision would be determined preoperatively based on the axis location of the plus cylinder on manifest refraction, topographic axis, and the location of the cone on elevation imaging. In this case, the incision would be oriented at 15 degrees and sutured securely after ICRS implantation. The final result may take up to 4 to 6 months. Guillermo Rocha, MD, FRCSC Brandon, Manitoba, Canada
REFERENCES 1. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003; 135:620–627 ~ero DP, Alio JL, Morbelli H, Uceda-Montanes A, El Kady B, 2. Pin Coskunseven E, Pascual I. Refractive and corneal aberrometric changes after intracorneal ring implantation in corneas with pellucid marginal degeneration. Ophthalmology 2009; 116: 1656–1664
- This is am interesting case of irregular against-therule (ATR) astigmatism. Considering the young age of the patient, I would not exclude future evolution toward clear PMD.1 The signs of this tendency in both eyes are evident, as seen in the corneal topography. Although the report does not mention corneal ultrasound pachymetry evaluations, the OCT images suggest a corneal thickness of approximately 500 mm or less with evident decentration of the corneal apex. All these elements are strongly indicative of an irregular cornea that would not be amenable to classic resolution of the visual defect.
557
In my opinion, the possible options are as follows: 1. Wait and ask the patient to return in 6 months. At that time, reexamine both eyes by performing corneal map tests, OCT, and ultrasound corneal pachymetry. I would also measure UDVA and CDVA and would expect potential evolution of the irregular astigmatism in the left eye as well. 2. Perform standard corneal CXL with deepithelialization in the right eye.2–5 Do not treat the left eye to allow time for the probable evolution of the disease, which might be very similar to that in the right eye. 3. Perform transepithelial CXLA,B in both eyes and after 1 month, perform a custom photorefractive keratectomy ablation in the right eye only.6 However, considering the fast evolution of CXL techniques,C,D,7 I would not treat this patient at the present time. Roberto Pinelli, MD Brescia, Italy
REFERENCES 1. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998; 42: 297–319 2. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003; 135:620–627 3. Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE. Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: longterm results. J Cataract Refract Surg 2008; 34:796–801 4. Kohlhaas M, Spoerl E, Speck A, Schilde T, Sandner D, Pillunat LE. Eine neue Behandlung der Keratektasie nach LASIK durch Kollagenvernetzung mit Riboflavin/UVA-Licht [A new treatment of keratectasia after LASIK with riboflavin/UVA light crosslinking]. Klin Monatsbl Augenheilkd 2005; 222:430–436 5. Kohlhaas M, Spoerl E, Schilde T, Unger G, Wittig C, Pillunat LE. Biomechanical evidence of the distribution of cross-links in corneas treated with riboflavin and ultraviolet A light. J Cataract Refract Surg 2006; 32:279–283 6. Krueger RR, Kanellopoulos AJ. Stability of simultaneous topography-guided photorefractive keratectomy and riboflavin/UVA cross-linking for progressive keratoconus: case reports. J Refract Surg 2010; 26:S827–S832 7. Raiskup F, Pinelli R, Spoerl E. Riboflavin osmolar modification for transepithelial corneal cross-linking, In press, Curr Eye Res 2012
OTHER CITED MATERIAL A. Boxer Wachler BS, “Corneal Collagen Crosslinking with Riboflavin,” Cataract & Refract Surg Today, January 2005, pages 73-74. Available at: http://www.crstoday.com/PDF%20Articles/0105/ PDFs/f12_boxerwaqchler.pdf. Accessed December 28, 2011 B. Pinelli R, “Corneal Cross-linking with Riboflavin: Entering a New Era in Ophthalmology,” Ophthalmology Times Europe, September 2006, pages 36-38. Available at: http://www.oteurope. com/ophthalmologytimeseurope/Cornea/Corneal-cross-linkingwith-riboflavin-entering-a-n/ArticleStandard/Article/detail/368411. Accessed December 28, 2011
J CATARACT REFRACT SURG - VOL 38, MARCH 2012
CONSULTATION SECTION
initially and treatment only in the case of a change in visual acuity or more pronounced topographic progression. Federico Badala, MD Milan, Italy
REFERENCES 1. Belin MW, Asota IM, Ambrosio R Jr, Khachikian SS. What’s in a name: keratoconus, pellucid marginal degeneration, and related thinning disorders. Am J Ophthalmol 2011; 152: 157–162 2. Millodot M, Shneor E, Albou S, Atlani E, Gordon-Shaag A. Prevalence and associated factors of keratoconus in Jerusalem: a cross-sectional study. Ophthalmic Epidemiol 2011; 18:91–97 3. McMonnies CW. Mechanisms of rubbing-related corneal trauma in keratoconus. Cornea 2009; 28:607–615 P, Malet F, Garra C, Gallois A, 4. Asri D, Touboul D, Fournie Malecaze F, Colin J. Corneal collagen crosslinking in progressive keratoconus: multicenter results from the French National Reference Center for Keratoconus. J Cataract Refract Surg 2011; 37:2137–2143 5. Angunawela RI, Arnalich-Montiel F, Allan BD. Peripheral sterile corneal infiltrates and melting after collagen crosslinking for keratoconus. J Cataract Refract Surg 2009; 35:606–607
Figure 4. Difference maps. Top: Right eye. Bottom: Left eye.
Should the patient's medical history be significant for intense eye rubbing, eye atopy, and related symptoms, I would counsel him regarding the possibility that simply stopping the eye rubbing might halt progression.3 I would then have him return 2 months after he begins topical treatment for atopy. Collagen crosslinking (CXL) would be my first-line intervention in the absence of a history of significant eye rubbing. Whether to recommend unilateral or bilateral CXL is a tough call in this case. I would start CXL the right eye and watch closely for further change in visual acuity or topography in the left eye. Should that happen, immediate CXL in the left eye is warranted. At present, the long-term effects of CXL for keratoconus are unknown; the ultraviolet-A (UVA) light might damage the corneal endothelial cells, lens, or retina, even though there is no evidence of this in published clinical studies. In addition, although rare, complications of the CXL procedure have been reported. These include corneal haze, corneal burns,4 bacterial and herpetic keratitis, and corneal melting.5 The patient's UDVA in the left eye is 20/20 . Thus, I would recommend follow-up visits every 2 months
- Corneal topography and scanning-slit elevation maps at baseline and 4 months later show little, if any, changes. Keratometry at 3.0 mm is 44.7 D in the right eye and 43.3 D in the left eye. The central corneal thickness (CCT) is 491 mm and 495 mm, respectively. The difference maps also appear stable with respect to axial power. Optical coherence topography confirms the presence of anterior and posterior elevation and inferotemporal thinning bilaterally. Axial curvature maps show a typical crab-claw pattern consistent with pellucid marginal degeneration (PMD). An additional test could be keratoscopy or the use of a simple handheld keratoscope, from which a pattern of “flat-flat-steep-steep-steep” ring mires can be observed progressively from the center to the inferior periphery. The progressive decline in vision could be due to an increase in accommodative demand from the intensive examinations. Nevertheless, the pattern of PMD is a concern. Despite the apparent stability of the objective tests, it is known that PMD presents in the 20- to 40-year age group and tends to progress over time. Furthermore, when inferior thinning occurs, optical and surgical options become limited. The following aspects are encouraging for surgical intervention in this case: keratometry readings less than 55.0 D, CCT greater than 400 mm, and good UDVA and CDVA. Because there is more cylinder in the right eye and the CDVA has begun to decline
J CATARACT REFRACT SURG - VOL 38, MARCH 2012
CONSULTATION SECTION
from 20/20, my approach would be summarized as follows: In the right eye, perform intrastromal corneal ring segment (ICRS) implantation inferiorly, which would be immediately followed by corneal CXL. In the left eye, perform CXL alone. The goals would be to improve UDVA and CDVA and to stabilize both eyes. For CXL, I would follow the protocol initially reported by Wollensak et al.1 In brief, a riboflavin 0.1% solution in dextran 20.0% is instilled on the deepithelialized cornea every 2 minutes for 30 minutes. This is followed by continued riboflavin instillation in the presence of UVA light (370 nm) for 30 minutes and a radiant exposure of 5.4 mJ/cm2, which corresponds to an irradiance of 3 mW/cm2. In brief, the ICRS implantation technique2 would be as follows: Create intrastromal channels using a 150 kHz femtosecond laser. Place a single 0.35 mm segment inferiorly at 400 mm depth, with a 6.8 mm internal diameter and a 7.8 mm external diameter. The location of the incision would be determined preoperatively based on the axis location of the plus cylinder on manifest refraction, topographic axis, and the location of the cone on elevation imaging. In this case, the incision would be oriented at 15 degrees and sutured securely after ICRS implantation. The final result may take up to 4 to 6 months. Guillermo Rocha, MD, FRCSC Brandon, Manitoba, Canada
REFERENCES 1. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003; 135:620–627 ~ero DP, Alio JL, Morbelli H, Uceda-Montanes A, El Kady B, 2. Pin Coskunseven E, Pascual I. Refractive and corneal aberrometric changes after intracorneal ring implantation in corneas with pellucid marginal degeneration. Ophthalmology 2009; 116: 1656–1664
- This is am interesting case of irregular against-therule (ATR) astigmatism. Considering the young age of the patient, I would not exclude future evolution toward clear PMD.1 The signs of this tendency in both eyes are evident, as seen in the corneal topography. Although the report does not mention corneal ultrasound pachymetry evaluations, the OCT images suggest a corneal thickness of approximately 500 mm or less with evident decentration of the corneal apex. All these elements are strongly indicative of an irregular cornea that would not be amenable to classic resolution of the visual defect.
557
In my opinion, the possible options are as follows: 1. Wait and ask the patient to return in 6 months. At that time, reexamine both eyes by performing corneal map tests, OCT, and ultrasound corneal pachymetry. I would also measure UDVA and CDVA and would expect potential evolution of the irregular astigmatism in the left eye as well. 2. Perform standard corneal CXL with deepithelialization in the right eye.2–5 Do not treat the left eye to allow time for the probable evolution of the disease, which might be very similar to that in the right eye. 3. Perform transepithelial CXLA,B in both eyes and after 1 month, perform a custom photorefractive keratectomy ablation in the right eye only.6 However, considering the fast evolution of CXL techniques,C,D,7 I would not treat this patient at the present time. Roberto Pinelli, MD Brescia, Italy
REFERENCES 1. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998; 42: 297–319 2. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003; 135:620–627 3. Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE. Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: longterm results. J Cataract Refract Surg 2008; 34:796–801 4. Kohlhaas M, Spoerl E, Speck A, Schilde T, Sandner D, Pillunat LE. Eine neue Behandlung der Keratektasie nach LASIK durch Kollagenvernetzung mit Riboflavin/UVA-Licht [A new treatment of keratectasia after LASIK with riboflavin/UVA light crosslinking]. Klin Monatsbl Augenheilkd 2005; 222:430–436 5. Kohlhaas M, Spoerl E, Schilde T, Unger G, Wittig C, Pillunat LE. Biomechanical evidence of the distribution of cross-links in corneas treated with riboflavin and ultraviolet A light. J Cataract Refract Surg 2006; 32:279–283 6. Krueger RR, Kanellopoulos AJ. Stability of simultaneous topography-guided photorefractive keratectomy and riboflavin/UVA cross-linking for progressive keratoconus: case reports. J Refract Surg 2010; 26:S827–S832 7. Raiskup F, Pinelli R, Spoerl E. Riboflavin osmolar modification for transepithelial corneal cross-linking, In press, Curr Eye Res 2012
OTHER CITED MATERIAL A. Boxer Wachler BS, “Corneal Collagen Crosslinking with Riboflavin,” Cataract & Refract Surg Today, January 2005, pages 73-74. Available at: http://www.crstoday.com/PDF%20Articles/0105/ PDFs/f12_boxerwaqchler.pdf. Accessed December 28, 2011 B. Pinelli R, “Corneal Cross-linking with Riboflavin: Entering a New Era in Ophthalmology,” Ophthalmology Times Europe, September 2006, pages 36-38. Available at: http://www.oteurope. com/ophthalmologytimeseurope/Cornea/Corneal-cross-linkingwith-riboflavin-entering-a-n/ArticleStandard/Article/detail/368411. Accessed December 28, 2011
J CATARACT REFRACT SURG - VOL 38, MARCH 2012