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Late Detachment of Descemet's Membrane After Subconjunctival THC:YAG (Holmium) Laser Thermal Sclerostomy Ab Externo
514
AMERICAN JOURNAL OF OPHTHALMOLOGY
October, 1993
the vitreous in idiopathic preretinal macular fibrosis. Am. J. OphthalmoI. 101:166, 1986. 2. Kado, M., and Trempe, C. L.: Role of the vitreous in branch vein occlusion. Am. J. OphthalmoI. 105:20,1988. 3. Akiba. J., Yoshida, A., and Trernpe, C. L.: Risk of developing a macular hole. Arch. OphthalmoI. 108:1088,1990. 4. Takahashi, M., Trempe, C. L., and Schepens, C. L.: Biomicroscopic evaluation and photography of posterior vitreous detachment. Arch. OphthalmoI. 98:665,1980. 5. Kakehashi, A., Akiba, J., and Trempe, C. L.: Vitreous photography with a +90-diopter double aspheric preset lens vs the El-Bayadi-Kajiura preset lens. Arch. OphthalmoI. 109:962, 1991.
Fig. 2 (Hikichi, Wajima, and Trempe). Vitreous photograph obtained with the wide-angle, preset slit-lamp lens. The posterior vitreous membrane (A) is attached to the fibrovascular proliferative tissue (B). Artifactual reflection from the preset lens is noted.
magnification and some reflection from the lens. However, these do not cause problems in clinical examination or in photographing the vitreous. Additionally, although a high-power preset lens has a short working distance and sometimes touches the patients' eyelashes." the design of this lens provides a convenient working distance from the patients' eyelashes even when focusing on the more anterior portions of the vitreous. This wide-angle, preset slit-lamp lens is useful in photographing the vitreous and can help determine the role of the vitreous in many vitreoretinal disorders.
References 1. Hirokawa, H., [alkh, A. E., Takahashi, M., Takahashi, M., Trernpe, C. L., and Schepens, C. L.: Role of
Late Detachment of Descemet's Membrane After Subconjunctival THC:YAG (Holmium) Laser Thermal Sclerostomy Ab Externo Vernon K. W. Wong, M.D., Steven B. Koenig, M.D., Erin S. Fogel, M.D., and Mark I. Freedman, M.D. Department of Ophthalmology, Medical College of Wisconsin (V.K.W.W., S.B.K., E.S.F.); and Eye Care Specialists, S.c. (M.I.F.).
Inquiries to Steven B. Koenig, M.D., Medical College of Wisconsin, 8700 W. Wisconsin Ave., Milwaukee, WI 53226.
Subconjunctival thulium, holmium, chromium (THC):YAG laser thermal sclerostomy is becoming an increasingly popular method of full-thickness filtering surgery. 1 The corneal complications associated with this technique have been uncommon. 1 We treated a patient who developed a detachment of Descemet's membrane eight months after THC:YAG laser sclerostomy. A 78-year-old white man with chronic openangle glaucoma underwent subconjunctival THC:YAG laser thermal sclerostomy ab externo in his pseudophakic left eye as described by Hoskins and associates.! An attempt to create a sclerostomy at the 6 o'clock meridian was stopped when Descemet's membrane striae were noted secondary to thermal contraction.
Vol. 116, No.4
Letters to The Joumal
515
Fig. 1 (Wong and associates). Slit-lamp photograph demonstrating corneal edema of temporal one half of cornea and underlying Descemet's detachment.
Fig. 2 (Wong and associates). Gonioscopic view of the inferior angle of the left eye demonstrating sclerostomy site (arrow) anterior to Schwalbe's line and a localized peripheral anterior synechia.
The probe was repositioned at the 5 o'clock meridian and a more anterior sclerostomy was performed with a total of 173 bursts at 100 m] per burst. The patient did well until eight months postoperatively, when he had decreased vision and ocular discomfort in his left eye. Ophthalmoscopy demonstrated a best-corrected visual acuity of R.E.: 20/30 and L.E.: 20/300. The intraocular pressure was 11 mm Hg in the left eye with a regimen of methazolamide, 25 mg, three times a day. Slit-lamp examination of the left eye disclosed an uninflamed bulbar conjunctiva with a thin, cystic conjunctival bleb at the inferior corneoscleral limbus. The temporal one half of the cornea, including the visual axis, demonstrated microcystic epithelial edema, stromal edema, and an underlying detachment of Descemet's membrane (Fig. 1). Gonioscopy disclosed a grade 4 angle (::=:: 40-degree iridocorneal angle) for 360 degrees and a sclerostomy site anterior to Schwalbe's line at the 5 o'clock meridian (Fig. 2). A small, localized peripheral anterior synechia was present immediately posterior to the sclerotomy. Previously reported complications of subconjunctival THC:YAG laser thermal sclerostomy ab externo include conjunctival burns, early hypotony, shallow anterior chamber, flat anterior chamber, early iris incarceration, late iris reincarceration, late lens changes, endophthalmitis, choroidal hemorrhage, and intraoperative hypherna.' Corneal complications include
transient folds in Descemet's membrane secondary to thermal contraction of the cornea and sclera, transient worsening of corneal edema in a patient with Fuchs' endotheliopathy, and bacterial keratitis.' Our patient had a detachment of Descemet's membrane after subconjunctival THC:YAG laser thermal sclerostomy ab externo. Although the mechanism remains unclear, it is possible that perforation and heat-induced contraction of Descemet's membrane resulted in eventual detachment of Descemet's membrane and subsequent corneal edema. Late detachment of Descemet's membrane may be associated with a sclerostomy site anterior to Schwalbe's line and should be recognized as a potential complication of subconjunctival THC:YAG laser thermal sclerostomy ab externo.
References 1. Iwach, A. G., Hoskins, H. D., jr., Drake, M. V., and Dickens, C. J.: Subconjunctival THC:YAG ("holmiurn") laser thermal sclerostomy ab externo. Ophthalmology 100:356, 1993. 2. Hoskins, H. D., Jr., Iwach, A. G., Vassiliadis, A., Drake, M. W., and Hennings, D. R.: Subconjunctival THC:YAG laser thermal sclerostomy ab externo. Ophthalmology 98: 1394, 1991.
AMERICAN JOURNAL OF OPHTHALMOLOGY
October, 1993
the vitreous in idiopathic preretinal macular fibrosis. Am. J. OphthalmoI. 101:166, 1986. 2. Kado, M., and Trempe, C. L.: Role of the vitreous in branch vein occlusion. Am. J. OphthalmoI. 105:20,1988. 3. Akiba. J., Yoshida, A., and Trernpe, C. L.: Risk of developing a macular hole. Arch. OphthalmoI. 108:1088,1990. 4. Takahashi, M., Trempe, C. L., and Schepens, C. L.: Biomicroscopic evaluation and photography of posterior vitreous detachment. Arch. OphthalmoI. 98:665,1980. 5. Kakehashi, A., Akiba, J., and Trempe, C. L.: Vitreous photography with a +90-diopter double aspheric preset lens vs the El-Bayadi-Kajiura preset lens. Arch. OphthalmoI. 109:962, 1991.
Fig. 2 (Hikichi, Wajima, and Trempe). Vitreous photograph obtained with the wide-angle, preset slit-lamp lens. The posterior vitreous membrane (A) is attached to the fibrovascular proliferative tissue (B). Artifactual reflection from the preset lens is noted.
magnification and some reflection from the lens. However, these do not cause problems in clinical examination or in photographing the vitreous. Additionally, although a high-power preset lens has a short working distance and sometimes touches the patients' eyelashes." the design of this lens provides a convenient working distance from the patients' eyelashes even when focusing on the more anterior portions of the vitreous. This wide-angle, preset slit-lamp lens is useful in photographing the vitreous and can help determine the role of the vitreous in many vitreoretinal disorders.
References 1. Hirokawa, H., [alkh, A. E., Takahashi, M., Takahashi, M., Trernpe, C. L., and Schepens, C. L.: Role of
Late Detachment of Descemet's Membrane After Subconjunctival THC:YAG (Holmium) Laser Thermal Sclerostomy Ab Externo Vernon K. W. Wong, M.D., Steven B. Koenig, M.D., Erin S. Fogel, M.D., and Mark I. Freedman, M.D. Department of Ophthalmology, Medical College of Wisconsin (V.K.W.W., S.B.K., E.S.F.); and Eye Care Specialists, S.c. (M.I.F.).
Inquiries to Steven B. Koenig, M.D., Medical College of Wisconsin, 8700 W. Wisconsin Ave., Milwaukee, WI 53226.
Subconjunctival thulium, holmium, chromium (THC):YAG laser thermal sclerostomy is becoming an increasingly popular method of full-thickness filtering surgery. 1 The corneal complications associated with this technique have been uncommon. 1 We treated a patient who developed a detachment of Descemet's membrane eight months after THC:YAG laser sclerostomy. A 78-year-old white man with chronic openangle glaucoma underwent subconjunctival THC:YAG laser thermal sclerostomy ab externo in his pseudophakic left eye as described by Hoskins and associates.! An attempt to create a sclerostomy at the 6 o'clock meridian was stopped when Descemet's membrane striae were noted secondary to thermal contraction.
Vol. 116, No.4
Letters to The Joumal
515
Fig. 1 (Wong and associates). Slit-lamp photograph demonstrating corneal edema of temporal one half of cornea and underlying Descemet's detachment.
Fig. 2 (Wong and associates). Gonioscopic view of the inferior angle of the left eye demonstrating sclerostomy site (arrow) anterior to Schwalbe's line and a localized peripheral anterior synechia.
The probe was repositioned at the 5 o'clock meridian and a more anterior sclerostomy was performed with a total of 173 bursts at 100 m] per burst. The patient did well until eight months postoperatively, when he had decreased vision and ocular discomfort in his left eye. Ophthalmoscopy demonstrated a best-corrected visual acuity of R.E.: 20/30 and L.E.: 20/300. The intraocular pressure was 11 mm Hg in the left eye with a regimen of methazolamide, 25 mg, three times a day. Slit-lamp examination of the left eye disclosed an uninflamed bulbar conjunctiva with a thin, cystic conjunctival bleb at the inferior corneoscleral limbus. The temporal one half of the cornea, including the visual axis, demonstrated microcystic epithelial edema, stromal edema, and an underlying detachment of Descemet's membrane (Fig. 1). Gonioscopy disclosed a grade 4 angle (::=:: 40-degree iridocorneal angle) for 360 degrees and a sclerostomy site anterior to Schwalbe's line at the 5 o'clock meridian (Fig. 2). A small, localized peripheral anterior synechia was present immediately posterior to the sclerotomy. Previously reported complications of subconjunctival THC:YAG laser thermal sclerostomy ab externo include conjunctival burns, early hypotony, shallow anterior chamber, flat anterior chamber, early iris incarceration, late iris reincarceration, late lens changes, endophthalmitis, choroidal hemorrhage, and intraoperative hypherna.' Corneal complications include
transient folds in Descemet's membrane secondary to thermal contraction of the cornea and sclera, transient worsening of corneal edema in a patient with Fuchs' endotheliopathy, and bacterial keratitis.' Our patient had a detachment of Descemet's membrane after subconjunctival THC:YAG laser thermal sclerostomy ab externo. Although the mechanism remains unclear, it is possible that perforation and heat-induced contraction of Descemet's membrane resulted in eventual detachment of Descemet's membrane and subsequent corneal edema. Late detachment of Descemet's membrane may be associated with a sclerostomy site anterior to Schwalbe's line and should be recognized as a potential complication of subconjunctival THC:YAG laser thermal sclerostomy ab externo.
References 1. Iwach, A. G., Hoskins, H. D., jr., Drake, M. V., and Dickens, C. J.: Subconjunctival THC:YAG ("holmiurn") laser thermal sclerostomy ab externo. Ophthalmology 100:356, 1993. 2. Hoskins, H. D., Jr., Iwach, A. G., Vassiliadis, A., Drake, M. W., and Hennings, D. R.: Subconjunctival THC:YAG laser thermal sclerostomy ab externo. Ophthalmology 98: 1394, 1991.