**4. Conclusion**

Acanthamoebic keratitis, first reported by Nagington et al. in Great Britain and by Jones et al. in the United States, is a painful progressive sight-threatening corneal disease. The infection is a rather frequently occurring disease all over the world which can still cause serious or even total loss of vision despite improved diagnostic and therapeutic options. *Acanthamoeba* spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide and have been isolated from soil, dust, air, natural and treated water, seawater, swimming pools, sewage, sediments, air-conditioning units, drinking water

Acanthamoeba keratitis is a potentially blinding condition of the eye, and any steps toward prevention of this disease are encouraged. It is recommended contact lens wearers to use daily disposable contact lenses to eliminate the contact lens case as a reservoir for Acanthamoeba. If daily disposable contact lens can not be used, then hydrogen peroxide cleaning solutions are preferred over the more common multipurpose solutions because of the increased efficacy of hydrogen peroxide against Acanthamoeba cysts. Planned replacement of contact lens storage cases may also help reduce contamination. It is important for eye care professionals not only to emphasize proper contact lens wear and hygiene in the prevention of infectious keratitis but also to maintain a high clinical suspicion for Acanthamoeba keratitis because an early diagnosis may lead to a better visual outcome (Tanhehco & Colby, 2010). The use of surfactant cleaner has been shown to be an effective way of removing Acanthamoeba trophozoites and cysts (Kilvington, 1993). In the light of these findings further research into the types of disinfectant used by patients with Acanthamoeba keratitis is required, with a view to calculating the relative risks of different lens type and disinfectant combinations. This series also show the importance of the fact that contact lens practitioners should ensure at the time of prescribing lenses that patients have understood all the disinfectant procedures (Illingworth et al., 1995). Gray et al. suggest leaving contact lens case open to dry air after heat disinfection. If hydrogen peroxide disinfection is the preferred solution, one has to use a two step hydrogen peroxide system. It is necessary to call one's attention to wash hands properly before handling contact lens cases and what is more important is to avoid homemade saline. The contact lens case should be replaced regularly. Nowadays the use of more frequently disposable contact lenses is highly recommended (Gray et al., 1995). Also the rub and rinse step should be mentioned as the critical part of the disinfection that may reduce significantly the microbiological load (Shih et al., 1985). Detailed education of contact lens wearers concerning of the entire disinfection procedure could reduce the incidence of Acanthamoeba keratitis further on. There is a persistent need to educate contact lens wearers continuously about the possible risk factors of Acanthamoeba keratitis, and since the frequency of Acanthamoeba keratitis appears to be largely determined by the ever changing trends in contact lens use, continued monitoring is indicated (Radford et al., 1998). All of the eye care practitioners have to call attention of all contact lens users to aware the wearing of soft contact lenses in case of swimming so as to reduce the number of patients with Acanthamoeba keratitis (Kaji et al., 2005; Kettesy et al., 2010). If even a soft contact lens wearer wants to swim, then daily disposable contact lens

Acanthamoebic keratitis, first reported by Nagington et al. in Great Britain and by Jones et al. in the United States, is a painful progressive sight-threatening corneal disease. The infection is a rather frequently occurring disease all over the world which can still cause serious or even total loss of vision despite improved diagnostic and therapeutic options. *Acanthamoeba* spp. are among the most prevalent protozoa found in the environment. They are distributed worldwide and have been isolated from soil, dust, air, natural and treated water, seawater, swimming pools, sewage, sediments, air-conditioning units, drinking water

**3. Prevention**

and swimming spectacles should be used.

**4. Conclusion**

treatment plants, bottled water, dental treatment units, hospitals and dialysis units, eyewash stations, and contact lenses and lens cases and as contaminants in bacterial, yeast, and mammalian cells. It mainly affects contact lens wearers with poor hygiene. In non contact lens wearers history of trauma in a garden is a risk factor. Patients' ages range from 4 to 64 years, with a mean age of 30 years, with no difference in genders. Infection usually affects only one eye, although it is occasionally bilateral. Most patients complain of symptoms of photophobia, pain, and tearing. The earliest signs may be non-specific and may take the form of epithelial micro erosions, irregularities, opacities or microcystic oedema, often with patchy anterior stromal infiltrates. There may be no fluorescein staining at the onset. Commonly, there is a dendriform keratitis that is often initially treated as herpes simplex infection. A ring infiltrate, usually with an overlying epithelial defect, is commonly seen. The ring may be incomplete, or occasionally it is double and concentric. The importance of early diagnosis cannot be overemphasized. We have to consider Acanthamoeba keratitis when symptoms associated with trauma especially involving vegetable matter or exposure to contaminated water, such as lake-, sea-, or spring water are mentioned. Acanthamoebic keratitis has to be differentiated from bacterial or fungal or herpes simplex virus keratitis. Diagnosis may be achieved by using different methods, including non invasive confocal microscopy, staining corneal scrapings with acridine orange, corneal scrapes or corneal biopsy specimens onto no nutrient agar containing *E. coli.,* cytological various staining methods, like indirect immunofluorescent-antibody assay, polymerase chain reaction (PCR) based method. The goals of medical therapy in Acanthamoeba keratitis include the eradication of viable cysts and trophozoites and rapid resolution of the associated inflammatory response. There is no single drug capable of eliminating the infection therefore drug combinations have been suggested as a treatment regimen. There are currently no drugs that are effective as monotherapy in Acanthamoeba keratitis, hence combinations are suggested. Acanthamoeba trophozoites are sensitive to most available chemotherapeutic agents (antibiotics, antiseptics, antifungals, antiprotozoals including metronidazole, antiviral, and antineoplastic agents). The diamidines and biguanides are currently the most effective cysticidal antiamoebics. With respect to the severity of the disease as well as the complications accompanying it there is a range of surgical methods to choose from. Corneal abrasion, cryosurgery, deep lamellar keratectomy with a conjunctival flap, amnion membrane transplantation, keratoplasty, deep lamellar keratoplasty. In some cases enucleation or evisceration is needed, because of severe inflammation, infection or secondary glaucoma. Antiamoebic therapy should be used before surgery and be continued postoperatively using drugs and doses that will minimize or avoid signs of toxicity. PHMB 0.02% has low clinical toxicity in most patients and is clinically less than that with either of the diamidines. We use PHMB 0.02% 6 to 8 times daily immediately after surgery, with an adequate level of topical steroid to control inflammation. This should be continued for at least 3 weeks while results of culture of the host keratectomy specimen are awaited. If viable organisms are cultured it is prudent to continue antiamoebic therapy 4 times daily while high-doses of steroids are needed usually for 6 months after surgery, as recurrent Acanthamoeba keratitis has occurred up to 3 months after an initially successful transplant. If culture of the excised host cornea is negative after 3 weeks we assume that most viable amoebae have been treated, and the topical antiamoebic therapy is reduced to 4 times daily and stopped after 1 month.

Keratoplasty in Contact Lens Related Acanthamoeba Keratitis 49

Acanthamoeba keratitis is a potentially blinding condition of the eye, and any steps toward prevention of this disease are encouraged. For prevention contact lens wearers are recommended to use daily disposable contact lenses to eliminate the contact lens case as a reservoir for Acanthamoeba. Hydrogen peroxide cleaning solutions are preferred over the more common multipurpose solutions. Planned replacement of contact lens storage cases may also help to reduce contamination. The rub and rinse step should be mentioned as the critical part of the disinfection. Detailed education of contact lens wearers concerning the entire disinfection procedure could minimize the incidence of Acanthamoeba keratitis further on. All of the eye care practitioners have to call attention of all contact lens users to aware the wearing of soft contact lenses in case of swimming so as to diminish the number of patients with Acanthamoeba keratitis. If even a soft contact lens wearer wants to swim,

Amoils SP. & Heney C. (1999) Acanthamoeba keratitis with live isolates treatet with cryosurgery and Fluconazole. *Am. J. Ophthalmol*, Vol. 127, No. 6, pp. 718-720 Awwad ST., Parmar DN., Heilman M., Bowman RW., McCulley JP.& Cavanagh HD. (2005)

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Beattie TK., Tomlinson A., McFadyen AK. Seal DV. & Grimason AM. (2003) Enhanced

Bourcier T., Patteau F., Borderie V., Baudrimont M., Rondeau N., Bonnel S., Chaumeil C.&

Clarke DW. & Niederkorn J. (2006) The pathophysiology of Acanthamoeba keratitis. *Trends*

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Results of penetrating keratoplasty for visual rehabilitation after acanthamoeba

and second-generation silicone hydrogel contact lenses. *Ophthalmology*, Vol. 113,

attachment of Acanthamoeba to extended-wear silicone hydrogel contact lenses.

Laroche L. (2004) Amniotic membrane transplantation for the treatment severe

Contact lens and noncontact lens characteristic. *Ophthalmology,* Vol. 102, No.9, pp.

Acanthamoeba keratitis with deep lamellar keratectomy and conjunctival flap.

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PC., Coakley E., Piessens E. & Wanke CA. (1997) Parasitic sinusitis and otitis in

then daily disposable contact lens and swimming spectacles should be applied.

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**5. References**

No. 1, pp. 117-125

1369-1373

Between 2001 and 2006 we treated 11 patients with Acanthamoeba keratitis. The patients were all soft contact lens wearers. The right eye was affected in six and the left in five cases. 82% of the infections occurred in the summer period between June and September. Beside long-lasting conservative treatment perforating keratoplasty was performed nearly in half of the cases.

In every case the infection was caused by poor and improper contact lens hygiene. All lenses involved were hydrogel soft lenses: 1 daily, 4 monthly and 1 yearly disposable. None of the lenses were extended or continuous wear. The half of the patients got the lenses from opticians, the other half from ophthalmologists.

Significant visual decrease was seen in almost all cases. Slit lamp examination showed corneal infiltration in 2 cases, ring infiltration (Fig. 1. and 2.) in 3 cases and corneal abscess in 1 case. The diagnosis of Acanthamoeba keratitis was based on corneal scraping in 2 cases, histology in 2 cases, and clinical findings in 2 cases.

Treatment started with antiamoebic agents in all patients: dibromopropamide or propamidin and polihexamethilen biguanidine was administered hourly in the first week, and then 5 times/day for at least 6 months. All patients were administered antibiotic drops 5 times a day for 2 weeks. We used steroid or non-steroid agents against the inflammation in seven cases.

In one case we performed corneal abrasion, but as it proved ineffective we followed it up with perforating keratoplasty.

Altogether penetrating keratoplasty was performed in six cases. In four cases keratoplasty was performed as an emergency (because of descemetocele) to save the eyeball, in two cases the operations were scheduled for visual rehabilitation.

All keratoplasties were perforating (penetrating), and central. All surgical procedures were done by two experienced surgeons. All cases were performed under retrobulbar anaesthesia. The trephination was performed with modified Geuder trephines. Donor corneas were obtained from the Eye Bank of our department. Only grafts with an endothelial cell count above 2000 cells/mm² were used. Graft fixation was performed in all cases with running nylon 10/0 sutures. We have had no intraoperative complications.

At the last follow up visit the average visual acuity was 0.43. In 3 cases it was only light perception, but the other 3 patients had very good corrected visual acuity (0.7-1.0).

In the emergency cases the visual acuity was much worse (light perception in 3 cases and 0.9 in one case, respectively), then in the proposed cases (0.7 and 1.0). In 5 cases the cornea graft was clear, rejection and decompensation developed only in one case.

Emergency keratoplasty is often the only possible intervention to prevent complete and irreversible vision loss in some cases. The main indications for this urgent surgical procedure are corneal perforations or imminent perforations, maintaining the integrity of the eyeball. Performing penetrating keratoplasty before scleral or peripheral corneal extension can minimize the risk of recurrence and poor outcome. Clear graft survival is lower if penetrating keratoplasty was performed during the acute, inflamed period of the disease compared to much higher clear graft survival when penetrating keratoplasty was performed in a quiet state of the disease. Perforating keratoplasty for visual restoration after resolution of *Acanthamoeba* keratitis in quiet eyes that are judged cyst-free by preoperative confocal microscopy appears to have an excellent long-term prognosis. Waiting at least 3 months after the discontinuation of medical therapy also appears helpful to rule out latent infection because of cyst reactivation and to allow the active inflammation to cease. Acanthamoeba keratitis is a potentially blinding condition of the eye, and any steps toward prevention of this disease are encouraged. For prevention contact lens wearers are recommended to use daily disposable contact lenses to eliminate the contact lens case as a reservoir for Acanthamoeba. Hydrogen peroxide cleaning solutions are preferred over the more common multipurpose solutions. Planned replacement of contact lens storage cases may also help to reduce contamination. The rub and rinse step should be mentioned as the critical part of the disinfection. Detailed education of contact lens wearers concerning the entire disinfection procedure could minimize the incidence of Acanthamoeba keratitis further on. All of the eye care practitioners have to call attention of all contact lens users to aware the wearing of soft contact lenses in case of swimming so as to diminish the number of patients with Acanthamoeba keratitis. If even a soft contact lens wearer wants to swim, then daily disposable contact lens and swimming spectacles should be applied.

#### **5. References**

48 Keratoplasties – Surgical Techniques and Complications

Between 2001 and 2006 we treated 11 patients with Acanthamoeba keratitis. The patients were all soft contact lens wearers. The right eye was affected in six and the left in five cases. 82% of the infections occurred in the summer period between June and September. Beside long-lasting conservative treatment perforating keratoplasty was performed nearly in half of

In every case the infection was caused by poor and improper contact lens hygiene. All lenses involved were hydrogel soft lenses: 1 daily, 4 monthly and 1 yearly disposable. None of the lenses were extended or continuous wear. The half of the patients got the lenses from

Significant visual decrease was seen in almost all cases. Slit lamp examination showed corneal infiltration in 2 cases, ring infiltration (Fig. 1. and 2.) in 3 cases and corneal abscess in 1 case. The diagnosis of Acanthamoeba keratitis was based on corneal scraping in 2 cases,

Treatment started with antiamoebic agents in all patients: dibromopropamide or propamidin and polihexamethilen biguanidine was administered hourly in the first week, and then 5 times/day for at least 6 months. All patients were administered antibiotic drops 5 times a day for 2 weeks. We used steroid or non-steroid agents against the inflammation in

In one case we performed corneal abrasion, but as it proved ineffective we followed it up

Altogether penetrating keratoplasty was performed in six cases. In four cases keratoplasty was performed as an emergency (because of descemetocele) to save the eyeball, in two cases

All keratoplasties were perforating (penetrating), and central. All surgical procedures were done by two experienced surgeons. All cases were performed under retrobulbar anaesthesia. The trephination was performed with modified Geuder trephines. Donor corneas were obtained from the Eye Bank of our department. Only grafts with an endothelial cell count above 2000 cells/mm² were used. Graft fixation was performed in all cases with running nylon 10/0 sutures. We have had no intraoperative complications. At the last follow up visit the average visual acuity was 0.43. In 3 cases it was only light

In the emergency cases the visual acuity was much worse (light perception in 3 cases and 0.9 in one case, respectively), then in the proposed cases (0.7 and 1.0). In 5 cases the cornea graft

Emergency keratoplasty is often the only possible intervention to prevent complete and irreversible vision loss in some cases. The main indications for this urgent surgical procedure are corneal perforations or imminent perforations, maintaining the integrity of the eyeball. Performing penetrating keratoplasty before scleral or peripheral corneal extension can minimize the risk of recurrence and poor outcome. Clear graft survival is lower if penetrating keratoplasty was performed during the acute, inflamed period of the disease compared to much higher clear graft survival when penetrating keratoplasty was performed in a quiet state of the disease. Perforating keratoplasty for visual restoration after resolution of *Acanthamoeba* keratitis in quiet eyes that are judged cyst-free by preoperative confocal microscopy appears to have an excellent long-term prognosis. Waiting at least 3 months after the discontinuation of medical therapy also appears helpful to rule out latent infection because of cyst reactivation and to allow the active inflammation to cease.

perception, but the other 3 patients had very good corrected visual acuity (0.7-1.0).

was clear, rejection and decompensation developed only in one case.

the cases.

seven cases.

with perforating keratoplasty.

opticians, the other half from ophthalmologists.

histology in 2 cases, and clinical findings in 2 cases.

the operations were scheduled for visual rehabilitation.

Keratoplasty in Contact Lens Related Acanthamoeba Keratitis 51

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**Part 2**

**Lamellar Keratoplasties**


**5.1 Analysis of low Al-low indium alloys**

Results of experimental work on 88Sn▬7.5Zn▬2.5Al▬2In and 88Sn▬7Zn▬2Al▬2.5 in lead-free soldering alloys are presented below.

Microstructures taken at different locations in the prepared solders showed variations, and the detailed analysis of the microstructures is given below.

**Figure 1** shows the microstructure, and **Figure 2** shows the corresponding EDAX line spectrum. The weight % of sigma phase is 0.6%, when we consider the aluminium peak and 1.55% in the zinc peak. The indium cluster is seen in the middle and this showed 0.23% sigma phase. Sigma phase is a hard, brittle phase and generally not desirable. The presence of indium seems to have decreased the amount of sigma phase.

Indium peaks are not seen in **Figures 3** and **4**, when EDAX image is considered, and sigma phase is around 0.93% in both the Zn peak(first from the left) and the aluminium peak(second from the left). Sigma phase % age is more in this case compared to the previous microstructure (**Figures 5** and **6**).

**Figure 1.** *Spectrum 1 electron image.*

**Figure 2.** *Spectrum 1 EDAX graph.*

**15**

**Figure 7.**

*Spectrum 10 electron image.*

*Role of Intermetallics in Lead-Free Alloys DOI: http://dx.doi.org/10.5772/intechopen.85515*

**Figure 4.**

**Figure 5.**

**Figure 6.**

*Spectrum 3 EDAX graph.*

*Spectrum 3 electron image.*

*Spectrum 2 EDAX graph.*

**Figure 3.** *Spectrum 2 electron image.*

*Role of Intermetallics in Lead-Free Alloys DOI: http://dx.doi.org/10.5772/intechopen.85515*

**Figure 4.** *Spectrum 2 EDAX graph.*

*Lead Free Solders*

**Figure 1.**

**Figure 2.**

*Spectrum 1 EDAX graph.*

*Spectrum 1 electron image.*

Microstructures taken at different locations in the prepared solders showed

**Figure 1** shows the microstructure, and **Figure 2** shows the corresponding EDAX line spectrum. The weight % of sigma phase is 0.6%, when we consider the aluminium peak and 1.55% in the zinc peak. The indium cluster is seen in the middle and this showed 0.23% sigma phase. Sigma phase is a hard, brittle phase and generally not desirable. The presence of indium seems to have decreased the amount of sigma phase. Indium peaks are not seen in **Figures 3** and **4**, when EDAX image is considered, and sigma phase is around 0.93% in both the Zn peak(first from the left) and the aluminium peak(second from the left). Sigma phase % age is more in this case

variations, and the detailed analysis of the microstructures is given below.

compared to the previous microstructure (**Figures 5** and **6**).

**14**

**Figure 3.**

*Spectrum 2 electron image.*

**Figure 5.** *Spectrum 3 electron image.*

**Figure 6.** *Spectrum 3 EDAX graph.*

**Figure 7.** *Spectrum 10 electron image.*

**Figure 8.** *Spectrum 10 EDAX graph.*

It is seen that 1.91% sigma phase is present in the Zn peak, whereas the indium peak, which occurs as two small peaks in the tin cluster, shows 0.20% sigma phase.

**Figures 7** and **8** show the microstructure and EDAX at another location. Here, sigma phase is 1.50% in the Zn peak and 0.55% in the aluminium peak. Indium peaks show 0.1% sigma and 1.425 sigma, respectively.


**5. Manufacturing of composite board from oil palm fronds**

The oil palm frond composite boards used in this study were made on a laboratory scale but follow the ISO standard. The oil palm fronds had been processed as compressed oil palm fronds to form such a potential composite board in this topic. The leaflets and epidermis are first manually removed from the fronds by a scraper. They were then sliced longitudinally into thin layers and compressed into 2-3 mm in thickness. The material was then air-dried under the shed before added with 12-15% of phenol and urea-formaldehyde resins and hot-pressed into composite boards.

**Figure 19.** *Layers of palm oil fronds being compressed using a hotpress machine.*

**Figure 20.** *Composite board from compressed oil palm fronds were trimmed.*

Hardner NH4Cl at 1% later added forming layers which were compressed into 350 mm (length)350 mm (width) x 20 mm (thickness) boards. This was done by transferring the material to a single-opening hydraulic hot-pressed machine with a platen temperature of 1255°C for phenol-formaldehyde resin and 1005°C for urea-formaldehyde resin and pressed into the desired shape for subsequent testing.

The composite board from compressed oil palm fronds was pressed using a three-step-down method of pressing among 40 secs/mm for phenol-formaldehyde resin, meanwhile 30 secs/mm for urea-formaldehyde resin. Thickness spacing bars of 20 mm thick were inserted between the hot platens during hot pressing to ensure the desired board thickness is shown in **Figure 19**. All these composite boards were trimmed as shown in **Figure 20** and cut into various size test specimens and then conditioned at 203°C and 653% relative humidity (RH) for 72 hours prior for testing to produce equilibrium moisture content of about 121%. More samples of the composite board from compressed oil palm fronds were shown in **Figures 21**–**24**.

**Figure 21.** *Front view of the compressed oil palm fronds board.*

**Figure 22.** *The compressed oil palm fronds boards can be laminating with veneers.*

*Processing and Properties of Oil Palm Fronds Composite Boards from* Elaeis guineensis *DOI: http://dx.doi.org/10.5772/intechopen.98222*

**Figure 23.** *The compressed oil palm fronds boards at differences thickness.*

#### **Figure 24.**

*High-performance micrograph of the phenol-formaldehyde composite board from compressed oil palm fronds at the longitudinal sectional view (2 magnification).*