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Macula Photocoagulation Lens
Letters to the Journal
Vol. 101, No.5
619
4. Weinmann, J. P., and Correll, J. T.: Histologic studies on the in vivo absorption of slightly and highly insolubilized gelatin films. Oral Surg. 4:891, 1951. 5. Schroder, M., WiIIumsen, H., Hart Hansen, J. P., and Hart Hansen, 0.: Peritoneal adhesion formation after the use of oxidized cellulose (Surgigel) and gelatin sponge (Spongostan) in rats. Acta Chir. Scand. 148:595, 1982.
Macula Photocoagulation Lens Fig. 2 (Antoszyk and associates). Early postoperative appearance after trabeculectomy combined with subconjunctival implantation of Gelfoam in patient with neovascular glaucoma, showing mottled appearance of gelatin material.
Follow-up was seven to ten months (average, nine months). All six patients had large filtering blebs and good intraocular pressure control in the early postoperative period. Both implant materials appeared to be well tolerated with no evidence of excessive inflammation or implant migration (Fig. 2). During the ensuing weeks, however, progressive scarring and eventual failure of the blebs occurred in the eye with the Gelfilm implant and in four of the five eyes with Gelfoam. Our histologic studies in rabbits were consistent with other reports that gelatin materials in various tissues throughout the body produce foreign-body reactions, with replacement of the gelatin by fibrous tissue.v' In addition, our experience in high-risk human eyes undergoing filtering surgery did not support the idea that gelatin implants are beneficial in the promotion of successful glaucoma filtering blebs.
References 1. Laval, J.: The use of absorbable gelatin film in glaucoma filtering surgery. Arch. Ophthalmol. 54:677, 1955. 2. Wilson, S. R.: New absorbable explants using gelatin and synthetic materials. Trans. Am. Ophthalmol. Soc. 81:966, 1983. 3. Stewart, R. H., Kimbrough, R. L., Bachh, H., and Allbright, M.: Trabeculectomy and modifications of trabeculectomy. Ophthalmic Surg. 10:76, 1979.
Lawrence A. Yannuzzi, M.D., and Jason S. Slakter, M.D. LuEsther T. Mertz Retinal Research Foundation, Manhattan Eye, Ear and Throat Hospital. Inquiries to Lawrence A. Yanuzzi, M.D., 525 Park Ave., New York, NY 10021.
The macula photocoagulation lens was developed by one of us (L.A.Y.) to treat lesions of the posterior pole of the retina, particularly those close to the fovea. This lens was designed to meet the requirements for optimal therapy of macular disease. These include enhanced fixation of the eyelids and immobilization of the globe, optimum clarity of the retinal image, and controlled increases in intraocular pressure to reduce choroidal blood flow, with minimal distortion of the corneal surface and altered visibility of the fundus. The macula photocoagulation lens is a modification and refinement of the Kreiger widefield fundus lens, which has been used extensively since 1966. The macula lens is constructed of lightweight, high-impact plastic. It incorporates a 14-mm hood used for insertion and removal of the lens as well as manipulation during treatment, and a 20-mm scleral flange for self-retention and fixation of the eyelids (Figure). The radius of the base curve has been steepened to 7.45 mm and the diameter of base curve area increased to 13.25 mm. This places the surface of the lens external to the corneosclerallimbus and minimizes contact with the cornea. The concave anterior curvature of the Kreiger lens has been replaced by a plano surface, to which a broad-band antireflective coating has been affixed. These modifications allow positive pressure to be applied against the sclera while minimizing pressure on the cornea. This enhances immobilization of the globe, essential for delicate macular laser therapy adjacent to the fovea. We
620
May, 1986
AMERICAN JOURNAL OF OPHTHALMOLOGY
BROADBAND ANTI-REFLECTIVE COATING
12.25MMR SCLERAL FLANGE 201'11'1 OVERALL DIA. 7.45MMR CORNEAL CURVE 13.251'11'1 CORNEAL CURVE DIA.
Figure (Yannuzzi and Slakter). Schematic drawing of the macula photocoagulation lens.
have found that the resultant ocular stability eliminates the need for retrobulbar anesthesia in most patients treated for juxtafoveal subretinal neovascularization. A second advantage of this design is that it permits a mild increase in intraocular pressure through indentation of the sclera by the surface ofthe lens without inducing corneal deformity. The small incremental increase in the intraocular pressure results in reduced blood flow through the low-pressure choroidal circulation. (The changes in choroidal flow with this induced intraocular pressure may be seen in eyes with atrophic or hypopigmented retinal pigment epithelium, such as in the myopic fundus.) This technique may prove to be successful in the reduction of subretinal hemorrhages during photocoagulation of sub retinal neovascularization, particularly when a wavelength, such as krypton red (647-nm), which penetrates deeply into the choroid is used. Another major feature of the macula photocoagulation lens is the substitution of a plano anterior surface for the concave surface of the Kreiger lens. While there is a decrease in the fundus field of view, there is an increase in the magnification of macular detail. This refinement also permits a broad antireflective coating to the applied to the anterior lens surface, thus increasing resolution and visibility of the macula. In addition, the antireflective coating maxi-
mizes laser transmission in the' visible spectrum, permitting efficient and consistent delivery of laser energy to the area being treated.
The x16 Slit-Lamp Eyepiece, a High Plus Lens for Indirect Biomicroscopy Elisha Bartov, M.D., Joseph Moisseiev, M.D., and Michael Blumenthal, M.D. Department of Ophthalmology, Goldschleger Eye Institute, Sheba Medical Center. Inquiries to Elisha Bartov, M.D., Department of Ophthalmology, Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel.
Lundberg! described biomicroscopic examination of the ocular fundus with a strong convex lens. In the 32 years since El-Bayadf first advocated the use of such a lens, others have reported the advantages of this technique. 2-5 It is easy to perform, it is easy to examine a moving eye, and it offers a large viewing field. Roserr' wrote:
Vol. 101, No.5
619
4. Weinmann, J. P., and Correll, J. T.: Histologic studies on the in vivo absorption of slightly and highly insolubilized gelatin films. Oral Surg. 4:891, 1951. 5. Schroder, M., WiIIumsen, H., Hart Hansen, J. P., and Hart Hansen, 0.: Peritoneal adhesion formation after the use of oxidized cellulose (Surgigel) and gelatin sponge (Spongostan) in rats. Acta Chir. Scand. 148:595, 1982.
Macula Photocoagulation Lens Fig. 2 (Antoszyk and associates). Early postoperative appearance after trabeculectomy combined with subconjunctival implantation of Gelfoam in patient with neovascular glaucoma, showing mottled appearance of gelatin material.
Follow-up was seven to ten months (average, nine months). All six patients had large filtering blebs and good intraocular pressure control in the early postoperative period. Both implant materials appeared to be well tolerated with no evidence of excessive inflammation or implant migration (Fig. 2). During the ensuing weeks, however, progressive scarring and eventual failure of the blebs occurred in the eye with the Gelfilm implant and in four of the five eyes with Gelfoam. Our histologic studies in rabbits were consistent with other reports that gelatin materials in various tissues throughout the body produce foreign-body reactions, with replacement of the gelatin by fibrous tissue.v' In addition, our experience in high-risk human eyes undergoing filtering surgery did not support the idea that gelatin implants are beneficial in the promotion of successful glaucoma filtering blebs.
References 1. Laval, J.: The use of absorbable gelatin film in glaucoma filtering surgery. Arch. Ophthalmol. 54:677, 1955. 2. Wilson, S. R.: New absorbable explants using gelatin and synthetic materials. Trans. Am. Ophthalmol. Soc. 81:966, 1983. 3. Stewart, R. H., Kimbrough, R. L., Bachh, H., and Allbright, M.: Trabeculectomy and modifications of trabeculectomy. Ophthalmic Surg. 10:76, 1979.
Lawrence A. Yannuzzi, M.D., and Jason S. Slakter, M.D. LuEsther T. Mertz Retinal Research Foundation, Manhattan Eye, Ear and Throat Hospital. Inquiries to Lawrence A. Yanuzzi, M.D., 525 Park Ave., New York, NY 10021.
The macula photocoagulation lens was developed by one of us (L.A.Y.) to treat lesions of the posterior pole of the retina, particularly those close to the fovea. This lens was designed to meet the requirements for optimal therapy of macular disease. These include enhanced fixation of the eyelids and immobilization of the globe, optimum clarity of the retinal image, and controlled increases in intraocular pressure to reduce choroidal blood flow, with minimal distortion of the corneal surface and altered visibility of the fundus. The macula photocoagulation lens is a modification and refinement of the Kreiger widefield fundus lens, which has been used extensively since 1966. The macula lens is constructed of lightweight, high-impact plastic. It incorporates a 14-mm hood used for insertion and removal of the lens as well as manipulation during treatment, and a 20-mm scleral flange for self-retention and fixation of the eyelids (Figure). The radius of the base curve has been steepened to 7.45 mm and the diameter of base curve area increased to 13.25 mm. This places the surface of the lens external to the corneosclerallimbus and minimizes contact with the cornea. The concave anterior curvature of the Kreiger lens has been replaced by a plano surface, to which a broad-band antireflective coating has been affixed. These modifications allow positive pressure to be applied against the sclera while minimizing pressure on the cornea. This enhances immobilization of the globe, essential for delicate macular laser therapy adjacent to the fovea. We
620
May, 1986
AMERICAN JOURNAL OF OPHTHALMOLOGY
BROADBAND ANTI-REFLECTIVE COATING
12.25MMR SCLERAL FLANGE 201'11'1 OVERALL DIA. 7.45MMR CORNEAL CURVE 13.251'11'1 CORNEAL CURVE DIA.
Figure (Yannuzzi and Slakter). Schematic drawing of the macula photocoagulation lens.
have found that the resultant ocular stability eliminates the need for retrobulbar anesthesia in most patients treated for juxtafoveal subretinal neovascularization. A second advantage of this design is that it permits a mild increase in intraocular pressure through indentation of the sclera by the surface ofthe lens without inducing corneal deformity. The small incremental increase in the intraocular pressure results in reduced blood flow through the low-pressure choroidal circulation. (The changes in choroidal flow with this induced intraocular pressure may be seen in eyes with atrophic or hypopigmented retinal pigment epithelium, such as in the myopic fundus.) This technique may prove to be successful in the reduction of subretinal hemorrhages during photocoagulation of sub retinal neovascularization, particularly when a wavelength, such as krypton red (647-nm), which penetrates deeply into the choroid is used. Another major feature of the macula photocoagulation lens is the substitution of a plano anterior surface for the concave surface of the Kreiger lens. While there is a decrease in the fundus field of view, there is an increase in the magnification of macular detail. This refinement also permits a broad antireflective coating to the applied to the anterior lens surface, thus increasing resolution and visibility of the macula. In addition, the antireflective coating maxi-
mizes laser transmission in the' visible spectrum, permitting efficient and consistent delivery of laser energy to the area being treated.
The x16 Slit-Lamp Eyepiece, a High Plus Lens for Indirect Biomicroscopy Elisha Bartov, M.D., Joseph Moisseiev, M.D., and Michael Blumenthal, M.D. Department of Ophthalmology, Goldschleger Eye Institute, Sheba Medical Center. Inquiries to Elisha Bartov, M.D., Department of Ophthalmology, Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel.
Lundberg! described biomicroscopic examination of the ocular fundus with a strong convex lens. In the 32 years since El-Bayadf first advocated the use of such a lens, others have reported the advantages of this technique. 2-5 It is easy to perform, it is easy to examine a moving eye, and it offers a large viewing field. Roserr' wrote: