Fig. 5.1
Case 1 (a) OD Kmax 47.4 D. (b) OD 2 months after: Kmax 48.7 D. (c) OS Kmax of 45.4 D. (d) OS 2 months after: Kmax 47.3 D
A 14-old-child was referred to eye examination after routine eye examination at school. He had never been examined by an optometrist or ophthalmologist in the past. In August 2014, he was examined in our eye clinic. He is constantly rubbing his eyes. His cousin has KC. His uncorrected distance visual acuity (UDVA) was 6/9 in OD and 6/10 in OS. Manifest refracted vision in OD was 6/6 with a correction of +1.00 / −1.50 D × 55°, and in OS the vision was 6/7.5 with a correction of +1.00 / −1.75 D × 20°. Topography evaluation showed KC with Kmax 47.4 D in OD and 45.4 D in OS. Central corneal thickness (CCT) was 458 μm in OD and 460 μm in OS. The corneas were clear. We offered CXL in both eyes. The mother was surprised and asked for reexamination, which was done in October 2014. Topographic evaluation showed increase of Kmax to 48.7 D in OD and 47.3 D in OS. Bilateral CXL scheduled: first in OS.
Decision-making
This is a problematic case. A child who never had complaints regarding visual function is diagnosed as having progressing KC in both eyes. The advantages and the disadvantages of CXL should be explained in detail to the parents, particularly the risks of a decrease of CDVA as a result of CXL in 6/6 eye. However, the mother was extremely surprised and concerned, and the delayed reexamination after 2 months is justified and recommended to help the parents accept the facts. In this particular case, there was no debate as for the need for CXL, and the decision is clear after corneal steepening of more than 1 D occurred within 2 months. In some of these cases, the progression may be slower and parents might further delay the procedure. A consultation with a reputable expert is suggested in such a case.
Case 2 (Fig. 5.2)
Fig. 5.2
Case 2 (a) OD before CXL with Kmax 51.7 D. (b) OD Kmax 51.5 D 15 months post-CXL. (c) OS Kmax 46.7 D. (d) OS Kmax progression to 49.4 D after 15 months
A 17-year-old female with KC from age 15 felt a decrease of vision during the last year. Her current spectacles were prescribed 7 months ago: in OD with a correction of −0.75 / −3.50 D × 56° the vision was 6/24, in OS with a correction of −0.25 / −1.50 D × 56° the vision was 6/12. Manifest refraction presented vision of 6/18 in OD with a correction of −0.50 / −4.50 D × 80° and in OS the vision was 6/10 with a correction of plano / −3.00 D × 80°. There were no previous records of topography. Our topography evaluation showed central KC with Kmax 51.7 D in OD and 46.7 D in OS. CCT was 463 μm in OD and 462 μm in OS.
Decision-making
This is a young patient with advanced KC. During 7 months, the spectacles-refracted astigmatism changed by 1.00 D in OD and by 1.50 D in OS indicating progression of KC in a young age which is a classical indication for CXL. We performed CXL in the OD with more advanced KC and followed OS. A year later the Kmax in OD did not change (51.5 D) and the CDVA improved to 6/12. On the other hand, the progression of KC in the OS continued: the refracted astigmatism increased by extra 0.75 D (plano / −3.75 × 90°), the topographic Kmax increased by 2.70 D (49.4 D), and the CDVA decreased to 6/12. CXL was performed.
Critical point: in a case of evidence-based bilateral progression of KC (increase in cylinder) in a young patient, treatment of the fellow eye should be done as soon as functional vision is achieved in the first treated eye.
Case 3 (Fig. 5.3)
Fig. 5.3
Case 3 (a) OD Kmax 48.1 D before CXL. (b) OS Kmax 51.5 D before CXL
A 31-year-old male, a computer technician, was first examined in our clinic in November 2013. He knows of KC for about 3 years. He uses scleral contact lenses (SCL), with the same dioptric power during the past 3 years, and does not have spectacles. He claimed his vision decreased in the last year particularly during driving and at nighttime. The patient was very concerned about further deterioration of vision in the future. The patient has no access to any refractive data regarding his vision in the past. His UDVA was 6/18− in each eye. With SCL his vision was 6/15 in OD and 6/12 in OS. Manifest refraction improved his OD vision to 6/10 with a correction of +0.25 / −2.75 D × 5° and to 6/10+ in OS with a correction of +0.50 / −4.00 D × 145°. The corneas were clear. The CCT was 485 μm in OD and 462 μm in OS. Topography evaluation indicated KC with Kmax 48.1 D in OD and 51.5 D in OS.
Decision-making
In November 2013, we decided to do CXL in OS and to follow OD. There was no topographic or refractive evidence of KC progression. However, the patient felt deterioration of driving vision, was emotionally scared, and demanded CXL be done immediately. His CDVA with spectacles was 6/10 in each eye, just enough for driving.
At the age of 31, a subjective claim of decreased vision without refractive information of KC progression on one hand and emotional status with marginal CDVA for driving on the other hand requires clinical judgment. We thought that KC should be followed but due to emotional status we offered Epi-On CXL, which would not interfere with his current work. However, the patient was very concerned and insisted on having standard CXL procedure, which was done in OS.
On October 2014, the refraction remained unchanged in OS with unremarkable improvement in topography. In the OD, there was a 0.75 D increase of refractive cylinder, but the topography and CDVA were stable. Patient was worried of OD KC progression but also from the long-term rehabilitation after standard CXL. He preferred Epi-On CXL procedure with an optional standard CXL in case of further progression in OD.
Case 4 (Fig. 5.4)
Fig. 5.4
Case 4 (a) OD Kmax 47.4 D. (b) OD after 7 months: Kmax 49.8 D. (c) OS Kmax 45.9 D. (d) OS Kmax after 7 months: 48.8 D
A 25-year-old female used spectacles from the age of 10 years. Her vision was stable during the last years; she used the same spectacles during the past 2 years and did not remember when the latest change in spectacles prescription was done. On August 2011, during the early stages of her first pregnancy, she started complaining of decrease of vision and discomfort. She was examined by an optometrist. Following topographic evaluation KC was diagnosed and she was referred to our cornea clinic. We examined her in November 2011, at 5th month of normal pregnancy. She used old spectacles with a correction of −1.00 / −1.75 D × 117° and 6/15 vision in OD and −0.50 / −0.50 D × 22° with vision of 6/7.5 in OS. Manifest refraction in OD was −1.00 / −2.50 D × 130° with vision improving to 6/10. In OS the correction and the vision remained unchanged. Topography showed bilateral KC with Kmax 47.4 D in OD and 45.9 D in OS. CCT was 460 μm in OD and 487 μm in OS. The rest of the eye examination was within normal limits.
Decision-making
A diagnosis of “surprise KC” during pregnancy is always problematic because the patient was considered normal with stable refraction, and it is usually not possible to retrieve any refractive data from the past. There is also no evidence that the KC process started during and not before pregnancy.
We assumed that OD had mild but stable KC which started progressing during the pregnancy. We decided not to CXL during pregnancy and suggested a follow-up after the delivery. Patient returned to clinic after 7 months in July 2012, still using the old spectacles. The manifest refraction in OD showed further progression of astigmatism and was −0.75 / −3.75 D × 120° without a change of CDVA. In OS the refraction changed to Plano / −1.25 D × 5° and vision was 6/6. Topographic Kmax was 49.8 D in the OD and 48.8 D in OS. CCT showed corneal thinning to 450 μm in OD and 470 μm in OS. The corneas were clear. The data indicated KC progression in both eyes. We offered standard CXL procedure in OD and thereafter in OS, which still maintained almost 6/6 vision. Patient refused the standard painful CXL procedure with a long rehabilitation period and preferred Epi-On CXL, which was immediately done. In OS Epi-On CXL was done 5 months later.
Case 5 (Fig. 5.5)
Fig. 5.5
Case 5 (a) OD Kmax 60.6 D. (b) Nine months after OD Kmax 66.0 D. (c) OD slit-lamp and (d) OD broad beam pictures of KC with corneal thinning and scar. (e) OS broad beam and (f) OS slit-lamp pictures of KC with corneal thinning and scar
A 21-year-old male with KC from the age of 15 years first examined in our clinic 2 years earlier in November 2010. Per his history, in 2008 he used RGP CL and his vision was in OD: 6/5 and in OS: 6/9+. He already had bilateral corneal scars. His vision decreased and in January 2010 he did corneal topography evaluation and started using SCL. In our examination, his CDVA with a SCL was in OD: 6/9 and in OS: 6/10−, he could not use other types of lenses or spectacles. The CCT was in OD: 354 μm and in OS: 391 μm. There were remarkable corneal scars in both central corneas. His OD Kmax was 66 D as compared to 60.6 D, 10 months earlier. In OS the Kmax was 61.6 D with nonsignificant difference during the last 10 months. He was a candidate for corneal transplantation in two hospitals.
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