Cornea Volume 34, Number 4, April 2015
Letters to the Editor
All Sweeping May Not Be Equal. A Comment on “Factors Affecting DSAEK Graft Lenticle Adhesion: An In Vitro Experimental Study” To the Editor: We read with great interest the article by Vaddavalli et al, 1 “Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study,” published in the June edition of Cornea. The authors have done an excellent job in this small in vitro study of identifying and evaluating several potential intraoperative variables affecting adherence of DSAEK grafts. In this study, the authors used an in vitro model to assess the interface gap (IG) present between DSAEK grafts and the recipient cornea. This IG was used to gauge graft adherence, a presumed corollary for graft dislocation in vivo. Intraoperative corneal massage (sweeping the corneal surface) was a variable studied in the fourth experimental set up. In this group, corneal sweeping was performed against a constant anterior chamber intraocular pressure (AC IOP) of 30 mm Hg. The authors found that corneal message did not improve adherence. Instead, it seemed to result in increased IG, leading the authors to hypothesize that this surgical maneuver “.may negatively influence DSAEK graft lenticule adhesion to the recipient cornea.” We disagree with the above statement. We view corneal message as a critical step and use this maneuver following a standard published DSAEK technique by Terry et al. 2 Using this same technique, our group found a very low dislocation rate of
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only 2%,3 similar to the 1.5% rate published by Terry et al. However, we massage the cornea against a much higher presumed AC IOP, close to 60 to 65 mm Hg (not described in previous articles) as approximated by a Barraquer Gravity tonometer (Ocular Instruments, Bellvue, WA) intraoperatively. We believe that sweeping against a much higher IOP is necessary to better facilitate egress of fluid as increased posterior pressure on the graft allows for less deformation of the cornea while sweeping. Conversely, sweeping with a lower posterior pressure (30 mm Hg) may actually succeed in deforming the cornea, separating the graft from the host, and allowing the influx of more interface fluid, as was found by these authors. It would be informative if the authors could repeat this arm of the study with a much higher AC IOP. Otherwise, it is concerning to dismiss sweeping as a useful surgical technique with only the information provided in this study. Financial disclosures/conflicts of interest: None reported. Paul Phillips, MD Valliammai Muthappan, MD Sightline Laser Ophthlamic Associates, Sewickley, PA
REFERENCES 1. Vaddavalli PK, Diakonis VF, Canto AP, et al. Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study. Cornea. 2014;33:552–554. 2. Terry MA, Shamie N, Chen ES, et al. Endothelial keratoplasty: a simplified technique to minimize graft dislocation, iatrogenic graft failure and pupillary block. Ophthalmology. 2008;115:1179–1186. 3. Phillips PM, Phillips LJ, Much JW, et al. Descemet’s stripping endothelial keratoplasty: six month results of the first 100 consecutive performed solo by a surgeon using 1 technique with 100% follow-up. Cornea. 2012;31: 1361–1364.
Tear Osmolarity in Ocular Graft-Versus-Host Disease To the Editor: We congratulate Berchicci et al1 for their study entitled “Tear Osmolarity in Ocular Graft-Versus-Host Disease.” The authors studied 56 patients with ocular chronic graft-versus-host-disease (cGVHD). They found that tear osmolarity was significantly inversely correlated with the tear film break-up time (TBUT) and Schirmer test and positively correlated with the ocular surface disease index (OSDI) score. The study may be evaluated as a cornerstone study in the understanding of ocular cGVHD. The ocular surface disease index includes 12 questions about signs and symptoms of dry eye. We wonder whether any one of these signs or symptoms correlate with tear osmolarity. We ask the authors to investigate the correlation between tear osmolarity and OSDI questions. Second, we wonder whether the etiologies of cGVHD (acute myeloid leukemia, acute lymphoblastic leukemia, etc) are related to the osmolarity and OSDI results. Is the etiologic disease predictive of cGVHD severity? We think that these new statistics may explore surprising results. Financial disclosures/conflicts of interest: None reported. Abdullah Ilhan, MD* Umit Yolcu, MD† *Ophthalmology Service, Erzurum Military Hospital, Erzurum, Turkey †Ophthalmology Service, Sarikamis¸ Military Hospital, Kars, Turkey
REFERENCE 1. Berchicci L, Iuliano L, Miserocchi E, et al. Tear osmolarity in ocular graft-versus-host disease. Cornea. 2014;33:1252–1256.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Letters to the Editor
All Sweeping May Not Be Equal. A Comment on “Factors Affecting DSAEK Graft Lenticle Adhesion: An In Vitro Experimental Study” To the Editor: We read with great interest the article by Vaddavalli et al, 1 “Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study,” published in the June edition of Cornea. The authors have done an excellent job in this small in vitro study of identifying and evaluating several potential intraoperative variables affecting adherence of DSAEK grafts. In this study, the authors used an in vitro model to assess the interface gap (IG) present between DSAEK grafts and the recipient cornea. This IG was used to gauge graft adherence, a presumed corollary for graft dislocation in vivo. Intraoperative corneal massage (sweeping the corneal surface) was a variable studied in the fourth experimental set up. In this group, corneal sweeping was performed against a constant anterior chamber intraocular pressure (AC IOP) of 30 mm Hg. The authors found that corneal message did not improve adherence. Instead, it seemed to result in increased IG, leading the authors to hypothesize that this surgical maneuver “.may negatively influence DSAEK graft lenticule adhesion to the recipient cornea.” We disagree with the above statement. We view corneal message as a critical step and use this maneuver following a standard published DSAEK technique by Terry et al. 2 Using this same technique, our group found a very low dislocation rate of
e12
| www.corneajrnl.com
only 2%,3 similar to the 1.5% rate published by Terry et al. However, we massage the cornea against a much higher presumed AC IOP, close to 60 to 65 mm Hg (not described in previous articles) as approximated by a Barraquer Gravity tonometer (Ocular Instruments, Bellvue, WA) intraoperatively. We believe that sweeping against a much higher IOP is necessary to better facilitate egress of fluid as increased posterior pressure on the graft allows for less deformation of the cornea while sweeping. Conversely, sweeping with a lower posterior pressure (30 mm Hg) may actually succeed in deforming the cornea, separating the graft from the host, and allowing the influx of more interface fluid, as was found by these authors. It would be informative if the authors could repeat this arm of the study with a much higher AC IOP. Otherwise, it is concerning to dismiss sweeping as a useful surgical technique with only the information provided in this study. Financial disclosures/conflicts of interest: None reported. Paul Phillips, MD Valliammai Muthappan, MD Sightline Laser Ophthlamic Associates, Sewickley, PA
REFERENCES 1. Vaddavalli PK, Diakonis VF, Canto AP, et al. Factors affecting DSAEK graft lenticle adhesion: an in vitro experimental study. Cornea. 2014;33:552–554. 2. Terry MA, Shamie N, Chen ES, et al. Endothelial keratoplasty: a simplified technique to minimize graft dislocation, iatrogenic graft failure and pupillary block. Ophthalmology. 2008;115:1179–1186. 3. Phillips PM, Phillips LJ, Much JW, et al. Descemet’s stripping endothelial keratoplasty: six month results of the first 100 consecutive performed solo by a surgeon using 1 technique with 100% follow-up. Cornea. 2012;31: 1361–1364.
Tear Osmolarity in Ocular Graft-Versus-Host Disease To the Editor: We congratulate Berchicci et al1 for their study entitled “Tear Osmolarity in Ocular Graft-Versus-Host Disease.” The authors studied 56 patients with ocular chronic graft-versus-host-disease (cGVHD). They found that tear osmolarity was significantly inversely correlated with the tear film break-up time (TBUT) and Schirmer test and positively correlated with the ocular surface disease index (OSDI) score. The study may be evaluated as a cornerstone study in the understanding of ocular cGVHD. The ocular surface disease index includes 12 questions about signs and symptoms of dry eye. We wonder whether any one of these signs or symptoms correlate with tear osmolarity. We ask the authors to investigate the correlation between tear osmolarity and OSDI questions. Second, we wonder whether the etiologies of cGVHD (acute myeloid leukemia, acute lymphoblastic leukemia, etc) are related to the osmolarity and OSDI results. Is the etiologic disease predictive of cGVHD severity? We think that these new statistics may explore surprising results. Financial disclosures/conflicts of interest: None reported. Abdullah Ilhan, MD* Umit Yolcu, MD† *Ophthalmology Service, Erzurum Military Hospital, Erzurum, Turkey †Ophthalmology Service, Sarikamis¸ Military Hospital, Kars, Turkey
REFERENCE 1. Berchicci L, Iuliano L, Miserocchi E, et al. Tear osmolarity in ocular graft-versus-host disease. Cornea. 2014;33:1252–1256.
Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
