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An Accurate Method to Determine Bowmans Layer Thickness In Vivo in the Human Cornea
Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
Linköping University, Department of Clinical and Experimental Medicine, Ophthalmology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Ophthalmology UHL/MH.
Linköping University, Department of Clinical and Experimental Medicine, Ophthalmology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Ophthalmology UHL/MH.
Linköping University, Department of Clinical and Experimental Medicine, Ophthalmology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Ophthalmology UHL/MH.
2012 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 53, no 4, 2354-2359 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE. To determine an accurate value for Bowmans layer (BL) thickness in vivo in humans. less thanbrgreater than less thanbrgreater thanMETHODS. Seventeen corneal transplant patients were examined preoperatively by laser-scanning in vivo confocal microscopy (IVCM), and corneal buttons were removed post-operatively and sectioned for light microscopy (LM). Nine corneas with uniformly thick BL by LM were used for thickness measurement. In the uniformly thick samples, probable overestimation of BL thickness in vivo by a first in vivo method (Method 1) led to the development of a revised in vivo method (Method 2). Method 2 was used to measure BL thickness in 20 healthy volunteers. less thanbrgreater than less thanbrgreater thanRESULTS. In nine patients, mean BL thickness prior to transplantation was 13.7 +/- 1.6 mu m by IVCM (Method 1) while BL thickness of the removed corneal button was 9.7 +/- 1.7 mu m by LM (P andlt; 0.001). The correlation of BL thickness between IVCM (Method 1) and LM was poor (P = 0.226). In 20 right eyes of 20 normal corneas, both in vivo methods were used to determine BL thickness. Mean BL thickness by Method 1 was 13.2 +/- 1.6 mu m and by Method 2 was 9.1 +/- 1.4 mu m (P andlt; 0.001). BL thickness measurements by both in vivo methods were highly correlated (P andlt; 0.001). less thanbrgreater than less thanbrgreater thanCONCLUSION. BL thickness by a revised in vivo method was close to LM values in this study and to values reported in fixed tissue in other studies. The authors believe this revised method provides the most accurate estimates of BL thickness in vivo to date.

Place, publisher, year, edition, pages
Association for Research in Vision and Ophthalmology (ARVO) , 2012. Vol. 53, no 4, 2354-2359 p.
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-78278DOI: 10.1167/iovs.11-8565ISI: 000303669400076OAI: oai:DiVA.org:liu-78278DiVA: diva2:531827
Note

Funding Agencies|European Union||

Available from: 2012-06-08 Created: 2012-06-08 Last updated: 2017-12-07
In thesis
1. Surgical outcomes of phototherapeutic keratectomy on Epithelial basement membrane dystrophy, and the characterisation of Bowman´s Layer
Open this publication in new window or tab >>Surgical outcomes of phototherapeutic keratectomy on Epithelial basement membrane dystrophy, and the characterisation of Bowman´s Layer
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background. Epithelial basement membrane dystrophy (EBMD) is a common disease of the anterior cornea that can lead to problems with vision and/or painful recurrent erosions of the corneal epithelium. Several treatment options have been used, but recurrence of EBMD after treatment is a problem. Excimer laser phototherapeutic keratectomy (PTK) has become an increasingly popular surgical option in recent years due to its accuracy, reproducibility, and good clinical outcomes. When treating EBMD with PTK, the anterior corneal structures including the epithelium, Bowman´s layer (BL), and subbasal nerves are disrupted or removed completely. Little is known about how BL, nerves, and the stroma recover after PTK treatment, or how they could influence recurrence of EBMD symptoms. Additionally, very little is known about the properties and actual thickness of BL in-vivo.

Aims. To improve the understanding and management of EBMD by investigating the clinical diagnosis and treatment of EBMD and its relationship to Bowman´s layer.

Method. An excimer laser was used to treat EBMD patients at the Department of Ophthalmology during the period 2001-2010. IVCM was used to perform pre- and postoperative examinations. In particular, images of anterior corneal structures, cells, and nerves in high-resolution were obtained. Additionally, a group of over 100 healthy volunteers underwent a full ophthalmic examination including IVCM. Other subjects examined in this work included a group of 17 patients who underwent full-thickness transplantation of the cornea.

Results and conclusions. Clinical follow-up revealed that PTK is an effective method of alleviating the clinical symptoms of EBMD, but the dystrophy can recur with time. Recurrence can be divided into clinical and morphologic types, and may depend upon treatment parameters including the type and depth of ablation. IVCM was found to be a useful screening tool pre- and postoperatively, and could prevent patients with symptoms, but no visible signs of EBMD on slit lamp examination, to go undiagnosed and untreated. BL was found to play a role in regenerative wound healing after PTK, and was also found to be important regarding the treatment and recurrence of EBMD. BL may present a physical barrier that protects the subepithelial nerve plexus thereby facilitating sensory recovery, and BL may also serve as a barrier that prevents direct traumatic contact with the corneal stroma, avoiding a stromal wound healing response. To aid in accurate assessment of BL in patients, an in vivo method for determining BL thickness was developed. This method could be an important tool to aid in clinical assessment and planned treatments of the anterior cornea. Using this tool, a large inter-individual variability in BL thickness and a strong negative correlation of BL thickness with age were found in a healthy population. Using IVCM, it was also found that subbasal nerves are pathologically reduced in EBMD compared to a healthy population, and that this nerve deficit does not improve in the long term after PTK treatment.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. 69 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1397
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-106248 (URN)10.3384/diss.diva-106248 (DOI)978-91-7519-391-5 (ISBN)
Public defence
2014-05-23, Nils-Holgersalen, Campus US, Linköpings universitet, Linköping, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2014-04-30 Created: 2014-04-30 Last updated: 2014-05-16Bibliographically approved

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Germundsson, JohanFagerholm, PerKoulikovska, MarinaLagali, Neil
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