CONSULTATION SECTION
20/16 UDVA does not properly demonstrate the loss of contrast sensitivity and quality of vision. The patient’s cornea should be supported with nonpreserved tears and low-dose corticosteroids. I would wait a minimum of 1 year after the PRK, and probably longer, before considering surgical intervention. In my experience, PRK or lamellar keratectomy will not provide the quality of the vision the patient currently experiences, and I expect significant improvement over the next 6 months to a year. A gas-permeable contact lens would likely provide resolution of the visual symptoms if the patient is willing to consider this option. As for the left eye, I would not offer surgery until the right eye achieves maximum visual rehabilitation. At this time, based on the mildly thin cornea with normal topography and low myopia, I would offer the patient thin-flap laser in situ keratomileusis (LASIK), which generally removes the issue of healing from the postoperative course. Photorefractive keratectomy is not always the safest option in corneal refractive surgery. Eric Donnenfeld, MD Rockville Centre, New York, USA
- The right eye has regular topography (Figure 2), a central superficial stromal scar (Figure 1), and good uncorrected acuity. Thus, it would be reasonable to watch and wait for further surface remodeling and resolution of symptoms. If the patient is still symptomatic at 1 year, with the ocular surface having been optimized, transepithelial phototherapeutic keratectomy (PTK) guided by the depth of the scar on OCT and the original treatment diameter should help. In general, the first step in treating a visually symptomatic superficial corneal scar is to try fitting a rigid contact lens to neutralize irregular astigmatism. However, this patient has a history of contact lens intolerance and regular topography. Therefore, it would be reasonable to jump straight to PTK. The laser used for PRK in the right eye in this case has built-in compensation for hyperopic shift in transepithelial treatment. Thus, the ablation should be refractively neutral, and in terms of the final topography, using the epithelium as a mask should have advantages over PTK with previous epithelial removal. Transepithelial treatment also confines the area of epithelium removed to the stromal ablation diameter, minimizing the area of the initial posttreatment epithelial defect. Some localized scars can be peeled using manual keratectomy. However, this scar is barely visible on OCT (Figure 3), suggesting that manual keratectomy would be less likely to work. Applying mitomycin-C (MMC) at the end of the
503
PTKdnotionally 0.02 mg/mL for 20 secondsdshould reduce the risk for haze recurrence. Measures to accelerate epithelial healing after PTK include pretreatment of underlying ocular surface disease, lubrication, and a switch to unpreserved medication. The latter is particularly important in the context of bandage soft contact lens wear postoperatively because soft lenses can absorb preservatives (eg, benzalkonium chloride) and act as a depot, potentiating toxicity and retarding healing. Contact lenses based on a phosphoryl choline copolymer may have advantages over other bandage lenses for this indication because of the large hydration shell surrounding the phosphoryl choline head group; however, this has not been proved clinically. The topographic profile (Figure 2) does not suggest that problems with a tight fit would be likely, but this should be checked. If the patient is keen to proceed with treatment in the left eye, LASIK should avoid any issues with delayed epithelial healing. Bruce Allan, MD, FRCS London, United Kingdom
- Acyclovir 400 mg 5 times a day is my usual drug and dose in this situation. Many of these cases heal promptly with anti-herpetic therapy, suggesting a herpes simplex virus (HSV) etiology. Of course, one should try to reduce medications with preservatives and eliminate antibiotics such as tobramycin and other aminoglycosides in favor of antibiotics with less epithelial toxicity. Inflammation can inhibit epithelial healing; thus, I usually continue twice daily topical corticosteroidsdnonpreserved when available. Liberal lubrication with nonpreserved artificial tears is often of benefit. If the epithelial defect persists beyond 10 days, I often prescribe 50% autologous serum drops 8 times a day. During these efforts, I typically continue the use of a high-oxygen-transmissible bandage contact lens that shows good movement with blinking at the slitlamp. I would encourage the patient to wait a minimum of 1 year from the original PRK before considering surgical intervention for the anterior stromal scar, especially in an eye like this that is near plano with otherwise good vision. In my experience, many of these types of scars diminish (disappearance of myofibroblasts and reabsorption of disordered matrix they secreted) spontaneously over time to the point that intervention dwith the attendant risk for another, more severe, nonhealing epithelial defectdis not necessary. If a decision is ultimately made that intervention is needed, I tend to favor transepithelial PTK followed
J CATARACT REFRACT SURG - VOL 40, MARCH 2014
20/16 UDVA does not properly demonstrate the loss of contrast sensitivity and quality of vision. The patient’s cornea should be supported with nonpreserved tears and low-dose corticosteroids. I would wait a minimum of 1 year after the PRK, and probably longer, before considering surgical intervention. In my experience, PRK or lamellar keratectomy will not provide the quality of the vision the patient currently experiences, and I expect significant improvement over the next 6 months to a year. A gas-permeable contact lens would likely provide resolution of the visual symptoms if the patient is willing to consider this option. As for the left eye, I would not offer surgery until the right eye achieves maximum visual rehabilitation. At this time, based on the mildly thin cornea with normal topography and low myopia, I would offer the patient thin-flap laser in situ keratomileusis (LASIK), which generally removes the issue of healing from the postoperative course. Photorefractive keratectomy is not always the safest option in corneal refractive surgery. Eric Donnenfeld, MD Rockville Centre, New York, USA
- The right eye has regular topography (Figure 2), a central superficial stromal scar (Figure 1), and good uncorrected acuity. Thus, it would be reasonable to watch and wait for further surface remodeling and resolution of symptoms. If the patient is still symptomatic at 1 year, with the ocular surface having been optimized, transepithelial phototherapeutic keratectomy (PTK) guided by the depth of the scar on OCT and the original treatment diameter should help. In general, the first step in treating a visually symptomatic superficial corneal scar is to try fitting a rigid contact lens to neutralize irregular astigmatism. However, this patient has a history of contact lens intolerance and regular topography. Therefore, it would be reasonable to jump straight to PTK. The laser used for PRK in the right eye in this case has built-in compensation for hyperopic shift in transepithelial treatment. Thus, the ablation should be refractively neutral, and in terms of the final topography, using the epithelium as a mask should have advantages over PTK with previous epithelial removal. Transepithelial treatment also confines the area of epithelium removed to the stromal ablation diameter, minimizing the area of the initial posttreatment epithelial defect. Some localized scars can be peeled using manual keratectomy. However, this scar is barely visible on OCT (Figure 3), suggesting that manual keratectomy would be less likely to work. Applying mitomycin-C (MMC) at the end of the
503
PTKdnotionally 0.02 mg/mL for 20 secondsdshould reduce the risk for haze recurrence. Measures to accelerate epithelial healing after PTK include pretreatment of underlying ocular surface disease, lubrication, and a switch to unpreserved medication. The latter is particularly important in the context of bandage soft contact lens wear postoperatively because soft lenses can absorb preservatives (eg, benzalkonium chloride) and act as a depot, potentiating toxicity and retarding healing. Contact lenses based on a phosphoryl choline copolymer may have advantages over other bandage lenses for this indication because of the large hydration shell surrounding the phosphoryl choline head group; however, this has not been proved clinically. The topographic profile (Figure 2) does not suggest that problems with a tight fit would be likely, but this should be checked. If the patient is keen to proceed with treatment in the left eye, LASIK should avoid any issues with delayed epithelial healing. Bruce Allan, MD, FRCS London, United Kingdom
- Acyclovir 400 mg 5 times a day is my usual drug and dose in this situation. Many of these cases heal promptly with anti-herpetic therapy, suggesting a herpes simplex virus (HSV) etiology. Of course, one should try to reduce medications with preservatives and eliminate antibiotics such as tobramycin and other aminoglycosides in favor of antibiotics with less epithelial toxicity. Inflammation can inhibit epithelial healing; thus, I usually continue twice daily topical corticosteroidsdnonpreserved when available. Liberal lubrication with nonpreserved artificial tears is often of benefit. If the epithelial defect persists beyond 10 days, I often prescribe 50% autologous serum drops 8 times a day. During these efforts, I typically continue the use of a high-oxygen-transmissible bandage contact lens that shows good movement with blinking at the slitlamp. I would encourage the patient to wait a minimum of 1 year from the original PRK before considering surgical intervention for the anterior stromal scar, especially in an eye like this that is near plano with otherwise good vision. In my experience, many of these types of scars diminish (disappearance of myofibroblasts and reabsorption of disordered matrix they secreted) spontaneously over time to the point that intervention dwith the attendant risk for another, more severe, nonhealing epithelial defectdis not necessary. If a decision is ultimately made that intervention is needed, I tend to favor transepithelial PTK followed
J CATARACT REFRACT SURG - VOL 40, MARCH 2014
